Skip to content
Hatch MatchHook the Horizon · field intelligence

Evidence

Where all of this came from.

39 reference records rest on 166 published pages, and 88 of those come from state and provincial natural-resources departments. That suits a set of records about what lives in the water those departments survey. The rest is federal survey work, university and extension guides, and interagency reports; the counts are below, and so is every claim the app makes, with the sources standing behind its record.

Carrier reviewed
2026-09-04
Next review due
2026-12-03
Review cadence
90 days
Publication state
approved preview

How to read this

Attribution is to a record, not to a sentence.

The carrier attaches a set of sources to a whole record. It does not say which page carried which line, so a claim below shows the sources standing behind its record rather than one citation of its own. Printing a single source per claim would look more precise and would be a mapping nobody checked. Per-claim attribution is on the list of things this app does not have yet.

  • National

    39

    A federal or national government body — USGS, NOAA, EPA, the Fish and Wildlife Service, the Park Service, Fisheries and Oceans Canada.

  • State

    88

    A state, provincial or commonwealth natural-resources department. Most of this carrier rests here, which suits it: these are the bodies that survey the water the records describe.

  • Interagency

    12

    A commission or joint survey run across several agencies, such as the Great Lakes Fishery Commission's forage task groups.

  • University

    27

    A university research programme, cooperative extension service or Sea Grant office. Published work, but not the agency that manages the water.

Showing 1023 of 1023 claims and 166 of 166 sources.

Claims

Every reviewed line in the app.

  • Mayfly →30 lines

    • What you can seeaquatic nymph with two or three tail filaments
    • What you can seeplate-like or feather-like abdominal gills
    • What you can seesegmented abdomen with developing wing pads on mature nymphs
    • What you can seewinged stages commonly hold wings upright
    • What you can seelong tail filaments remain visible on winged stages
    • What you can seetrailing shuck can support emergence-stage observation
    • What argues against ithairy wings held tent-like over the body suggest caddisfly
    • What argues against ittwo tails alone do not separate every mayfly from a stonefly
    • What argues against itchunky larva with legs clustered near hardened head and terminal hooks is more consistent with caddisfly
    • What argues against itportable case or case-like structure points away from mayfly
    • What argues against itlegless soft body with only prolegs and no true tails points toward midge rather than mayfly
    • Declared limitA mayfly result means the observation is broadly consistent with Ephemeroptera, not that this exact species is hatching here now.
    • Declared limitMayflies vary considerably; the most useful field result combines life stage, silhouette, tails, gills or wings, size, position, and movement.
    • Declared limitThis preview does not claim a current emergence, distribution, or fish feeding focus.
    • Size bandnymph: 3-25 (most trout-stream species 6-18) mm
    • Size bandsubimago: 4-20 mm
    • Size bandadult: 4-20 mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Life stagenymph
    • Life stagesubimago
    • Life stageadult
    • Where it sitssubsurface (nymph)
    • Where it sitssurface film (emergence/dun)
    • Where it sitsspent on surface (spinner)
    • How it movesswimming undulation
    • How it movescrawling on substrate
    • How it movesdrifting with current
    • How it movesupright wings resting

  • Caddisfly →32 lines

    • What you can seelarva may be associated with a portable case, a fixed retreat, or no case at all (free-living and net-spinning forms are common)
    • What you can seehardened head and part of the thorax with a softer, often worm-like abdomen
    • What you can seethree pairs of thoracic legs bunched near the head
    • What you can seeterminal prolegs or hooks at the rear that grip rock, debris, or the case
    • What you can seepupal stage precedes the winged adult
    • What you can seehairy wings held tent-like or inverted-V over the body when at rest
    • What you can seeno long tail filaments on winged stages
    • What argues against itthree tail filaments point away from caddis larva
    • What argues against ita winged insect near water is not sufficient for a caddis identification
    • What argues against itupright sailboat wings and long tails point toward mayfly
    • What argues against itwings held flat and parallel along the body favor stonefly adult over caddis
    • What argues against ittwo long tails on a nymph without case or terminal hooks favors stonefly or mayfly
    • What argues against itlarge robust larva with prominent lateral filaments and strong mandibles favors hellgrammite over caddis
    • Declared limitCase-building behavior varies and absence of a visible case does not rule out caddis.
    • Declared limitThis preview does not claim a current emergence or recommend a specific pattern.
    • Declared limitBroad group only; many families exist.
    • Size bandlarva: 3-40 (most 5-25) mm
    • Size bandpupa: 4-30 mm
    • Size bandadult: 4-25 mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Life stagelarva
    • Life stagepupa
    • Life stageadult
    • Where it sitssubsurface (larva/pupa)
    • Where it sitssurface or near-surface (emergence)
    • Where it sitsresting with tent wings
    • How it movescrawling with case
    • How it movesswimming pupa
    • How it movesfluttering adult flight
    • How it movescase-dragging

  • Stonefly →31 lines

    • What you can seeaquatic nymph with two tail filaments
    • What you can seetwo long antennae on the nymph
    • What you can seethread-like gills often at the thorax or leg bases rather than leaf-like gills down the abdomen
    • What you can seenymph often associated with flowing freshwater and submerged stone or debris
    • What you can seewinged adult remains near aquatic habitat
    • What you can seeadult wings held flat and parallel along the body at rest (not upright, not tent-like)
    • What you can seetwo pairs of wing pads on mature nymphs
    • What you can seegenerally two claws on each leg
    • What argues against itthree tail filaments point toward many mayfly nymphs rather than stonefly
    • What argues against itplate-like or feather-like gills along the abdomen favor mayfly over stonefly
    • What argues against ita two-tail observation without body and gill detail remains ambiguous
    • What argues against itportable case points strongly away from stonefly
    • What argues against itupright wings and delicate body favor mayfly
    • What argues against ittent-like or inverted-V wings at rest favor caddisfly adult over stonefly
    • What argues against itlaterally flattened shrimp-like form that swims on its side is a scud, not a stonefly
    • Declared limitHabitat and emergence timing vary by species.
    • Declared limitThis record cannot establish a current observation, site-specific water status, or fishing success.
    • Declared limitTwo tails alone do not separate every stonefly from every mayfly.
    • Size bandnymph: 5-50 (many western species large) mm
    • Size bandadult: 6-50 mm
    • Water typeriver
    • Water typestream
    • Water typespring
    • Life stagenymph
    • Life stageadult
    • Where it sitssubsurface under stones or debris
    • Where it sitscrawling on rock edges
    • Where it sitsadult near aquatic habitat
    • How it movescrawling on rock or debris
    • How it movespoor swimming
    • How it movesstraight heavy flight

  • Midge (non-biting) →29 lines

    • What you can seesoft-bodied larva with a distinct sclerotized head capsule
    • What you can seepair of anterior prolegs under the head and posterior prolegs on the last segment (no segmented true legs)
    • What you can seeoften held in a C- or J-shape when collected
    • What you can seeno long filamentous tails comparable to mayfly or stonefly cerci
    • What you can seemany forms lack a portable case; some construct simple tubes but not the classic caddis portable case
    • What argues against itthree or two long tail filaments point strongly away from Chironomidae
    • What argues against ita portable case of plant or mineral material with the classic caddis architecture points to Trichoptera
    • What argues against itplate-like or feather-like abdominal gills characteristic of many mayfly nymphs are absent
    • What argues against itupright sailboat wings with long tails favor mayfly adults over midges
    • What argues against itlarge robust form with lateral abdominal filaments and powerful mandibles is consistent with hellgrammite, not midge
    • Declared limitChironomidae is an enormous and morphologically diverse family; this record supports only a broad non-biting midge hypothesis.
    • Declared limitBlood-red forms (hemoglobin) are common in low-oxygen sediments but color alone is not diagnostic.
    • Declared limitThis preview never claims a current hatch, density, or fishing pattern. Size and absence of insect tails/cases are the strongest field separators.
    • Size bandlarva: 2-20 (most commonly 3-12; many <10) mm
    • Size bandpupa: 2-15 mm
    • Size bandadult: 2-12 mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Water typespring
    • Life stagelarva
    • Life stagepupa
    • Life stageadult
    • Where it sitssubsurface in sediment or on vegetation
    • Where it sitsdrifting
    • Where it sitssurface film (emergence)
    • How it moveswriggling or undulating
    • How it movesanchored by posterior prolegs
    • How it movesadult weak flight near water

  • Hellgrammite (dobsonfly larva) →22 lines

    • What you can seelarge aquatic larva with three pairs of thoracic legs
    • What you can seeeight pairs of lateral filamentous appendages on the abdomen, each often with a gill tuft at the base
    • What you can seepowerful, visible mandibles (pincers)
    • What you can seeterminal pair of prolegs or appendages bearing claws
    • What you can seetypically found under rocks in well-oxygenated flowing water
    • What argues against itlong filamentous cerci (two or three tails) without the full set of lateral abdominal filaments favor stonefly or mayfly
    • What argues against itportable case points away from Megaloptera
    • What argues against ittiny or small soft larva without lateral filaments and with only prolegs is consistent with midge, not hellgrammite
    • What argues against itwinged stages of dobsonflies are terrestrial adults and are outside this aquatic-larva reference
    • What argues against itlaterally flattened shrimp-like swimming form is a scud, not a hellgrammite
    • Declared limitHellgrammite refers specifically to the aquatic larva of dobsonflies (Corydalidae); related alderfly larvae (Sialidae) are smaller and differ in filament arrangement.
    • Declared limitSize and the combination of lateral filaments + strong mandibles are the primary field separators; this is not a species-level identification.
    • Declared limitThis record does not imply current density, fishing utility, or site-specific presence.
    • Size bandlarva: 25-100 (commonly 40-80 when mature) mm
    • Water typeriver
    • Water typestream
    • Life stagelarva
    • Where it sitsunder stones in riffles and runs
    • Where it sitssubsurface crawler
    • How it movesstrong crawling on rock
    • How it movespoor swimmer
    • How it movescan deliver a defensive pinch

  • Scud / Amphipod (crustacean lookalike) →23 lines

    • What you can seebody compressed from side to side (taller than wide when viewed from above)
    • What you can seeseven pairs of walking legs; first pairs often claw-like
    • What you can seeno wings, no wing pads, no insect-style cerci
    • What you can seedistinct black eyes on many forms
    • What you can seecharacteristically swims sideways
    • What argues against itany true insect tails (two or three long filaments) rule out Amphipoda
    • What argues against itportable case, abdominal gills of mayfly type, or upright/tent insect wings rule out scud
    • What argues against itsegmented true insect legs limited to three pairs (hexapod) plus possible prolegs differ from the seven-pair amphipod pattern
    • What argues against itthis record is provided only as a disambiguation aid; it is not an insect order and never a hatch match target
    • Declared limitScuds are crustaceans, not insects. This record exists solely to reduce false positive calls of mayfly, caddis, or stonefly nymphs when the observer sees a laterally flattened, side-swimming form.
    • Declared limitNever treat a scud result as a biological 'hatch' cue for trout or as an insect identification.
    • Declared limitBroad Amphipoda only; many genera exist and habitat preferences vary.
    • Size bandlarva: 3-20 (most 5-15) mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Water typespring
    • Life stagelarva
    • Where it sitsamong vegetation, leaf packs, or substrate
    • Where it sitsswimming in open water near cover
    • How it movesswims on its side (sideswimmer)
    • How it movesrapid darting
    • How it movescrawls among plants

  • Terrestrials (ants, beetles, hoppers) →25 lines

    • What you can seeThe animal is a land insect that has fallen, blown, or crawled onto the water — not an aquatic nymph that grew wings here
    • What you can seeHoppers: long jumping hind legs, blocky body, wings folded along the back if present
    • What you can seeAnts: distinct pinched waist, elbowed antennae; winged forms (alates) often raft in groups after a flight
    • What you can seeTerrestrial beetles: hard elytra meeting in a line; legs not bunched at a caddis-style head
    • What you can seeNo aquatic gills, no portable case, no long mayfly or stonefly cerci
    • What argues against itAbdominal plate gills, two or three long tail filaments, or a portable case point to an aquatic order, not a fallen terrestrial
    • What argues against itA labium mask or caudal lamellae point to Odonata, not a hopper or ant
    • What argues against itA fish-shaped silhouette with a school is forage, not a terrestrial insect
    • What argues against itHard diving-beetle adults that swim under water with an air bubble belong with Aquatic beetles, not this fallen-terrestrial group
    • Declared limitThis is a broad observation class for summer/early-fall bank and meadow insects on the water, not a species-level identification and not a hatch.
    • Declared limitHopper, ant, and beetle silhouettes differ; the useful field result is 'fallen terrestrial' plus the silhouette you actually saw.
    • Declared limitThis preview never claims a current fall, density, or a pattern that will catch fish here today.
    • Size bandant: 3-12 (most 4-8) mm
    • Size bandbeetle: 4-20 (many 6-14) mm
    • Size bandhopper: 10-40 (most 12-25) mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Life stageadult
    • Where it sitssurface film after a fall from bank or vegetation
    • Where it sitsbankside grass and riparian vegetation
    • Where it sitswindward lake margins in summer
    • How it movesstruggling or kicking on the surface
    • How it moveshopping on bank vegetation
    • How it movesdrifting inert after drowning

  • Baitfish / forage silhouette →26 lines

    • What you can seeA fish-shaped body with a distinct head, fins, and a forked or rounded tail fin — not six legs and not insect wings
    • What you can seeOften seen as a school or tight cluster rather than a single drifting insect
    • What you can seeSize is typically larger than trout-stream insects (often well over 20 mm)
    • What you can seeNo gills of insect type, no case, no cerci, no elytra
    • What you can seeThis group exists so a forage observation is not forced into an insect order
    • What argues against itAny true insect tails, portable case, abdominal gills, labium mask, or six jointed legs rules out forage fish
    • What argues against itA single tiny worm-like form without fins is a midge or worm, not baitfish
    • What argues against itA laterally flattened side-swimming crustacean is a scud, not a minnow
    • What argues against itNever treat a forage silhouette as a hatch match target
    • Declared limitThis is a silhouette observation class for forage fish, not a species identification and not a hatch.
    • Declared limitMany genera exist (shiners, dace, darters, shad, fry of gamefish). The useful field result is 'forage silhouette', not a named minnow.
    • Declared limitThis record never claims current bait presence, density, or that predatory fish are feeding on it now.
    • Size bandfry: 10-30 mm
    • Size bandjuvenile: 30-80 mm
    • Size bandadult: 40-150 (most observed forage 40-90) mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Water typespring
    • Life stageadult
    • Where it sitsmid-column or just under the surface
    • Where it sitsover weed edges and points
    • Where it sitsalong shade lines and drop-offs
    • How it movesflashing school
    • How it movescoordinated turns
    • How it movesdarting then holding

  • Damselfly / Dragonfly (Odonata) →27 lines

    • What you can seeAquatic nymph with an extendable grasping labium (mask) used to seize prey — the strongest single Odonata field tell
    • What you can seeDamselfly nymphs: slender body and three leaf-like caudal lamellae at the rear (these are gills, not mayfly cerci)
    • What you can seeDragonfly nymphs: robust, often flattened, no long external tail filaments; gills internal
    • What you can seeWing pads present on mature nymphs
    • What you can seeAdults: large compound eyes, two pairs of equal or near-equal wings; damselfly wings usually fold along the body, dragonfly wings stay out
    • What argues against itRound filamentous cerci without a labium mask favor mayfly or stonefly, not Odonata
    • What argues against itA portable case or hard-head/soft-abdomen caddis plan is not Odonata
    • What argues against itA tiny proleg-only worm is a midge, not a damselfly nymph
    • What argues against itA fish-shaped school is forage, not an odonate
    • Declared limitOdonata is a broad order. This record supports a damselfly/dragonfly hypothesis, not a family or species call.
    • Declared limitCaudal lamellae on damselfly nymphs are commonly mistaken for mayfly tails; the labium mask is the honest separator.
    • Declared limitThis preview does not claim a current emergence, density, or fishing pattern.
    • Size bandnymph: 8-50 (damselfly nymphs often 10-25; dragonfly nymphs often 15-45) mm
    • Size bandadult: 20-80 wingpread typical; body 25-70 mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Water typespring
    • Life stagenymph
    • Life stageadult
    • Where it sitsamong vegetation and stems (climbers)
    • Where it sitson or in substrate (sprawlers / burrowers)
    • Where it sitsadults hunting over stillwater and slow margins
    • How it movesclimbing vegetation
    • How it movesjet propulsion (dragonfly nymph)
    • How it movesside-to-side caudal lamellae swim (damselfly nymph)
    • How it movesstrong adult hunting flight

  • Aquatic beetles (Coleoptera) →27 lines

    • What you can seeAdult: hard elytra (wing covers) meeting in a straight line down the back — not tent wings, not upright sailboat wings
    • What you can seeMany adults carry a visible air bubble or silvery film under the elytra or at the posterior when diving
    • What you can seeLarva: elongate, often with a hardened head and visible mandibles, three pairs of thoracic legs, no portable case and no caddis terminal-hook plan as the primary tell
    • What you can seeNo long cerci of mayfly/stonefly type; no labium mask of Odonata
    • What argues against itA portable mineral or leaf case is caddis, not a beetle
    • What argues against itPlate-like abdominal gills and long tail filaments favor mayfly
    • What argues against itA labium mask favors Odonata
    • What argues against itA fallen hopper or ant on the film without elytra or an air bubble belongs with Terrestrials
    • What argues against itA fish school is forage, not Coleoptera
    • Declared limitColeoptera in water includes diving beetles, whirligigs, water scavengers and others; this is a broad group only.
    • Declared limitAdult elytra plus an air bubble is the strongest field combination; larvae are easier to confuse with other orders and need mandibles + lack of case/cerci.
    • Declared limitThis preview never claims current density or a fishing pattern.
    • Size bandlarva: 5-40 (many 8-25) mm
    • Size bandadult: 3-35 (predaceous diving beetles often 8-20) mm
    • Water typeriver
    • Water typestream
    • Water typelake-margin
    • Water typespring
    • Life stagelarva
    • Life stageadult
    • Where it sitsswimming in the water column (diving beetles)
    • Where it sitsat the surface film (whirligigs)
    • Where it sitsamong vegetation and on substrate
    • How it movesrowing with hind legs
    • How it movescarrying a silvery air bubble or film
    • How it moveswhirling at the surface
    • How it moveslarva crawling or swimming with mandibles forward

  • Shad (gizzard and threadfin) →27 lines

    • What you can seeSharp-edged scutes along the midline of the belly give a sawtooth keel you can feel by running a finger forward
    • What you can seeLast dorsal ray is drawn out into a long trailing filament — the single most useful character in this group
    • What you can seeBlunt snout with a small inferior mouth; the upper jaw projects beyond the lower
    • What you can seeDark shoulder spot behind the upper edge of the gill cover, strongest on young fish and often absent on adults
    • What you can seeDeeply forked tail and a deep, slab-sided silvery body
    • What you can seeOne soft dorsal fin with no spines
    • What argues against itAn adipose fin between dorsal and tail points to cisco or another salmonid, not to shad
    • What argues against itA large eye wider than the snout and no trailing dorsal filament points to alewife
    • What argues against itA spiny front dorsal fin rules shad out entirely — clupeids have none
    • What argues against itThreadfin shad are separated from gizzard shad by a terminal mouth, a projecting lower jaw and yellow fins; this record does not try to split them in the field
    • Declared limitThis record covers gizzard and threadfin shad together. Separating the two reliably needs anal-ray and lateral-scale counts on a fish in hand, which is not a field observation.
    • Declared limitShad are cold-sensitive and winter die-offs are a documented natural event in the Midwest, not a sign of pollution.
    • Declared limitAdult gizzard shad grow beyond the size most gamefish will take; young-of-year fish are the forage-relevant stage.
    • Size bandyoung-of-year: 100-180 mm
    • Size bandadult: 150-520 mm
    • Water typereservoir
    • Water typelake-open
    • Water typeriver
    • Water typelake-margin
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsnear surface in large moving schools
    • Where it sitsopen water of reservoirs and large rivers
    • Where it sitsshoreline and open water both used
    • How it movesconstantly moving schools
    • How it movesleaping or skittering across the surface when pressed
    • How it movesmost active at dusk and at night

  • Alewife / river herring →27 lines

    • What you can seeBelly scutes are unusually sharp — the 'sawbelly' — stronger than on most other members of the herring family
    • What you can seeEye diameter is greater than the length of the snout; the folk name is big-eyed herring
    • What you can seeSingle dull dark shoulder spot just behind the upper margin of the gill cover
    • What you can seeLower jaw juts out beyond the upper
    • What you can seeNo adipose fin, and no trailing dorsal filament
    • What you can seeDeeply forked tail; slab-sided silvery body
    • What argues against itA small fleshy adipose fin behind the dorsal separates cisco from alewife — the cisco has one and the alewife does not
    • What argues against itA long thread trailing from the back fin and a short blunt snout point to gizzard shad
    • What argues against itA spiny front dorsal rules out every herring
    • What argues against itBlueback herring is separated by a dark body-cavity lining, which is not a field observation on a live fish
    • Declared limitLandlocked Great Lakes alewife run much smaller than the anadromous Atlantic form; the size bands here follow Great Lakes and survey figures.
    • Declared limitThe 100 mm total-length figure separating age-0 from older fish is a survey convention, not a hard biological boundary.
    • Declared limitThis record does not claim alewife are present in any particular water.
    • Size bandyoung-of-year: 55-100 mm
    • Size bandadult: 100-237 mm
    • Water typelake-open
    • Water typelake-margin
    • Water typeriver
    • Water typereservoir
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsopen water for most of the year
    • Where it sitsnear the lake bottom in winter and early spring
    • Where it sitsyoung-of-year fish stay above the thermocline by day
    • Where it sitsruns into tributaries and shallow water to spawn
    • How it movesschooling in open water
    • How it movesmoves shallow as water warms past about 15 degrees Celsius

  • Cisco / lake herring →20 lines

    • What you can seeA small fleshy adipose fin sits between the dorsal fin and the tail — this is a trout and salmon family character and no herring has one
    • What you can seeBody is elongate and nearly round in cross section rather than slab-sided
    • What you can seeSilvery with a deep blue-green back; fins largely clear
    • What you can seeDeeply forked tail
    • What you can seeNo belly scutes and no sawtooth keel
    • What argues against itA sharp sawtooth belly keel points to a herring — shad or alewife — not to cisco
    • What argues against itA deep, strongly slab-sided body points away from cisco
    • What argues against itA spiny front dorsal rules out cisco
    • What argues against itSources disagree on whether the cisco's lower jaw projects; do not use jaw position to separate it
    • Declared limitCisco need deep, cold lakes; this record is about what the animal looks like, not about whether your water holds them.
    • Declared limitSources conflict on jaw position and gill-raker counts vary by water body, so neither is offered as a field character.
    • Declared limitNo young-of-year size is given because no source consulted stated one.
    • Size bandadult: 170-400 mm
    • Water typelake-open
    • Water typelake-margin
    • Water typeriver
    • Life stageadult
    • Where it sitspelagic — open water, midwater in large and deep inland lakes
    • Where it sitsmoves shallow over rock to spawn
    • How it movesschooling in open water

  • Shiners and minnows →24 lines

    • What you can seeA single soft dorsal fin, never preceded by a spine — all fins of native species are soft-rayed
    • What you can seePelvic fins sit on the belly, beneath the dorsal fin, rather than forward under the throat
    • What you can seeThin lips and no teeth in the jaws
    • What you can seeNo sawtooth belly keel, and no adipose fin
    • What you can seeSpottail shiner carries a prominent dark spot at the base of the tail
    • What argues against itA spiny front dorsal fin rules out every native minnow — that is a perch or a sunfish
    • What argues against itA sawtooth belly keel points to a young shad or alewife rather than a shiner
    • What argues against itAn adipose fin points to the trout and salmon family
    • What argues against itCarp and goldfish are cyprinids but carry a stout spine at the front of the dorsal and anal fins
    • Declared limitThis record covers the family, not a species. Separating emerald from spottail from golden shiner in the field is beyond what this reference supports.
    • Declared limitThe size band spans four common forage species: fathead around 38-75 mm, emerald 64-89 mm, spottail 50-150 mm, golden shiner to about 200 mm.
    • Declared limitNo source consulted stated whether young-of-year minnows school separately from adults.
    • Size bandadult: 38-200 mm
    • Water typelake-margin
    • Water typelake-open
    • Water typeriver
    • Water typestream
    • Water typereservoir
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitslarge schools in midwater or at the surface
    • Where it sitsnear shore and around vegetation
    • How it movesschooling
    • How it movesspawning in shallow water over sand or mud

  • Yellow perch, young-of-year →23 lines

    • What you can seeTwo dorsal fins that do not join: the front one spiny, the rear one soft-rayed
    • What you can seeSix or seven broad dark vertical bars down a yellow to brassy flank — bars, not a horizontal stripe
    • What you can seeTwo spines at the front of the anal fin
    • What you can seeSpines on the tip of the gill cover
    • What you can seeSlightly forked tail and a small forward-pointing mouth
    • What argues against itA dark opercular ear flap and a much deeper, rounder body point to a young sunfish rather than a perch
    • What argues against itA single soft dorsal with no spines rules out perch — that is a minnow or a young herring
    • What argues against itA sawtooth belly keel rules out perch
    • Declared limitAgency trawl surveys put age-0 yellow perch at roughly 60 to 80 mm total length by late summer and autumn; earlier in the season they are much smaller, hatching at 4 to 7 mm.
    • Declared limitNo source consulted gave a school size specific to young-of-year perch, only 50 to 200 fish for perch schools in general.
    • Declared limitSeparating a young-of-year perch from a young sunfish is assembled here from family characters; no source consulted made the comparison directly.
    • Size bandyoung-of-year: 5-80 mm
    • Water typelake-margin
    • Water typelake-open
    • Water typeriver
    • Water typereservoir
    • Life stageyoung-of-year
    • Where it sitsnear-shore pelagic schools for the first 30 to 40 days after hatching
    • Where it sitsthen a shift to the bottom as littoral bottom dwellers
    • Where it sitsschools of young fish stay near shore while adults are farther out
    • How it movesschooling by size and age
    • How it movesfeeding in daylight and largely inactive at night
    • How it movesmoving deeper to overwinter

  • Sunfish, young-of-year (bluegill and kin) →21 lines

    • What you can seeSpiny and soft dorsal portions joined into one fin, or divided only slightly — not two separate fins
    • What you can seeA dark opercular flap, the ear flap, at the rear corner of the gill cover
    • What you can seeThree or more spines at the front of the anal fin
    • What you can seeVertical barring is prominent on young fish and fades on adults
    • What you can seeVery deep, slab-sided body and a small mouth
    • What argues against itTwo clearly separate dorsal fins with a gap between them, and spines on the gill-cover tip, point to a young perch
    • What argues against itSunfish lack the opercular serrations or spines that the perches carry
    • What argues against itA single soft dorsal with no spines rules out sunfish
    • Declared limitFirst-year bluegill average roughly 25 to 50 mm; fry return from open water to weed cover at about 21 to 25 mm.
    • Declared limitThis record covers Lepomis broadly; separating bluegill from pumpkinseed or redear as young fish is not supported here.
    • Declared limitSeparating a young sunfish from a young perch is assembled from family characters; no source consulted made the comparison directly.
    • Size bandyoung-of-year: 21-50 mm
    • Water typelake-margin
    • Water typereservoir
    • Water typeriver
    • Water typestream
    • Life stageyoung-of-year
    • Where it sitsfry stay pelagic for several weeks
    • Where it sitsthen move to littoral vegetation at about 21 to 25 mm
    • Where it sitswarm quiet water with at least moderate vegetation
    • How it movesholding in and around weed and cover rather than open-water schooling

  • Crayfish →27 lines

    • What you can seeOne pair of pincers, much larger than the walking legs
    • What you can seeA domed carapace over the fused head and thorax, with a triangular rostrum between the eyes
    • What you can seeAn obviously segmented abdomen ending in a flat, fan-like tail
    • What you can seeLong outer antennae and a shorter inner pair
    • What you can seeThe abdomen is flattened top to bottom, not side to side
    • What argues against itA body flattened side to side, with no enlarged pincers, points to a scud or amphipod
    • What argues against itFreshwater shrimp have a cylindrical abdomen with only slight side-to-side flattening and no greatly enlarged first claws
    • What argues against itA soft newly moulted crayfish is the same animal, not a different one — the shell stays soft for two to four days
    • Declared limitSources disagree on basic counts: whether crayfish have four pairs of walking legs plus chelipeds or five pairs with the first enlarged, and whether the abdomen has five or seven segments. Neither count is offered as a field character.
    • Declared limitSize varies with moult stage. Young crayfish moult six to fourteen times in the first year and adults only one to three times, and a single moult can add up to fifteen percent in length.
    • Declared limitNo source consulted stated that crayfish enter the invertebrate drift, so this reference makes no claim that they do.
    • Size bandyoung-of-year: 8-40 mm
    • Size bandadult: 25-150 mm
    • Water typestream
    • Water typeriver
    • Water typelake-margin
    • Water typereservoir
    • Water typespring
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitson and in the bottom
    • Where it sitsunder rocks and logs by day
    • Where it sitsburrowed into the substrate
    • Where it sitsrarely far from the bottom
    • How it moveswalking slowly forward on the legs
    • How it movesflicking rapidly backwards when threatened by curling the tail fan under the body
    • How it movesactive largely at night

  • Leech →23 lines

    • What you can seeA sucker at each end of the body — the decisive character
    • What you can seeSegmented, with each segment further wrinkled into annuli
    • What you can seeNo bristles anywhere on the body
    • What you can seeFlattened in cross section, not round like an earthworm
    • What you can seeExpands and contracts dramatically, so any single length measurement is approximate
    • What argues against itBundles of fine bristles along the segments point to an aquatic worm, not a leech
    • What argues against itA flattened body with no segments and no suckers is a planarian or flatworm
    • What argues against itBoth leeches and planarians are flattened, so flattening alone separates nothing
    • Declared limitNo source consulted states whether leeches are nocturnal or day-active beyond the observation that they usually avoid light, and none addressed seasonal activity.
    • Declared limitNo source consulted reports leeches in the invertebrate drift.
    • Declared limitThe size range is very wide because leeches stretch; treat any observed length as approximate.
    • Size bandadult: 5-500 mm
    • Water typelake-margin
    • Water typeriver
    • Water typestream
    • Water typereservoir
    • Life stageadult
    • Where it sitson vegetation, under stones and logs, or in bottom muck
    • Where it sitswarm calm shallow water, especially where weed is thick
    • Where it sitstravels along the underside of the surface film
    • How it movesgraceful undulating swimming
    • How it moveslooping along like an inchworm using both suckers
    • How it movesusually avoids light

  • Aquatic worms →22 lines

    • What you can seeMany segments, round in cross section, with no legs and no hardened head
    • What you can seeBundles of fine bristles on most segments, sometimes visible
    • What you can seeColour from white through red and tan to brown or black
    • What you can seeBlunt at both ends with few other features
    • What argues against itA sucker at each end means a leech, not a worm
    • What argues against itA hard head capsule with prolegs at each end means a midge larva, which is an insect — red midge larvae and red worms are both called bloodworms
    • What argues against itA cranefly larva's head is concealed under the skin, so looking for a hard head will not separate a cranefly from a worm; use the fleshy lobes at its hind end instead
    • What argues against itNo segments at all, and a very long thin body, points to a horsehair worm
    • Declared limitThe upper size figure is uncertain: two readings of the same regional guide returned different mid-range values. Treat 1 to 150 mm as a wide envelope rather than a measurement.
    • Declared limitNo source consulted describes aquatic worms generally as free-swimming in the water column; one naidid species is recorded swimming with a wriggling motion.
    • Declared limitNo source consulted reports oligochaetes in the invertebrate drift, and none was found describing terrestrial earthworms washing into streams and being eaten there.
    • Size bandadult: 1-150 mm
    • Water typelake-margin
    • Water typeriver
    • Water typestream
    • Water typereservoir
    • Life stageadult
    • Where it sitsin soft sediment and silt
    • Where it sitshead buried in a tube in the bottom with the rest of the body extending upward into the water
    • Where it sitsquiet water with decaying organic material
    • How it movesstretching and pulling like an earthworm
    • How it moveswaving in the current while anchored in the sediment

  • Sand lance (sand eel) →33 lines

    • What you can seeNo pelvic fins anywhere on the underside — the single most useful character in the group
    • What you can seeOne dorsal fin running most of the length of the back, 49 to 69 rays, folding down into a groove
    • What you can seeLower jaw projects past the upper, with a sharp point at the chin
    • What you can seeNo teeth in the jaws at all
    • What you can seeFine oblique lines along the flank where the scales sit in dermal folds, and a loose fold of skin along the edge of the belly
    • What you can seeDeeply forked tail and a lateral line running high on the body
    • What argues against itPelvic fins of any kind rule out sand lance outright — the family has none
    • What argues against itTwo dorsal fins with a gap between them is a silverside, not a sand lance
    • What argues against itA short triangular dorsal near the middle of the back is the herring and menhaden pattern
    • What argues against itA snout overhanging the mouth is an anchovy; sand lance lead with the lower jaw
    • What argues against itSharp belly scutes forming a sawtooth keel is a clupeid; a sand lance has only soft skin folds there
    • Declared limitThe two Atlantic species cannot be separated by eye. Sources state that even DNA barcoding on the standard gene fails to split them, and that the difference rests on plicae and vertebral counts. This record does not offer an American-versus-Northern call.
    • Declared limitSources disagree on typical size by a wide margin: USGS describes three to six inches while the NOAA synthesis gives maxima of 20 cm and 30 cm for the two species. Both are shown rather than averaged.
    • Declared limitNo source consulted describes sand lance showering at the surface or being pushed onto beaches by predators, despite how often that is said. This record makes no such claim.
    • Declared limitNo source consulted states whether an adipose fin is present, or gives an eye-to-snout proportion.
    • Size bandyoung-of-year: 4-60 mm
    • Size bandadult: 76-300 mm
    • Water typesurf
    • Water typeinshore
    • Water typenearshore
    • Water typeoffshore
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsburied in clean coarse sand, or in the water column directly above it
    • Where it sitsover well-washed sand and fine gravel, never mud or rock
    • Where it sitsshallow nearshore water, often less than two metres
    • Where it sitsdense schools from the surface down to about twenty metres
    • How it movesdives head-first into the sand at sixty to seventy-five degrees and disappears
    • How it movesleaves the sand at twenty to sixty degrees, accelerating to about 120 cm per second within the first metre and a half
    • How it movesundisturbed schools cruise at 30-50 cm per second; feeding schools slow to 15-25
    • How it movespacks into a tight ball when threatened rather than scattering
    • Sources disagreeDiel burial runs both ways in the sources. Alaska Department of Fish and Game states Pacific sand lance feed and school by day and burrow at night; a NOAA Fishery Bulletin field study found substantially more buried during the day than at night, 119.8 per square metre against 47.7. Neither is offered here as the rule.
    • Sources disagreeThe Pacific species carries two names across agency sources: Ammodytes personatus in the NOAA systematic revision and on one Washington page, Ammodytes hexapterus on another Washington page and in Alaska's. Both travel with this record.

  • Silversides →28 lines

    • What you can seeTwo dorsal fins, clearly separated, the first small and spiny
    • What you can seeMouth angled upward, with the top jaw extendible — the lower jaw leads
    • What you can seeA thick, bright, iridescent silver stripe running the length of the flank
    • What you can seeTranslucent green above, often cross-hatched along the back, pale to translucent below
    • What you can seeLarge eye, forked tail
    • What argues against itOne dorsal fin instead of two, with a translucent body and a narrow faint stripe, is a bay anchovy
    • What argues against itA single short dorsal near midbody with sharp belly scutes is menhaden or a herring
    • What argues against itNo pelvic fins and one very long dorsal is a sand lance
    • What argues against itA blunt flattened head with a small mouth is a mullet, which also has two dorsals — the head settles it
    • Declared limitThis record covers the family, not a species. Connecticut's own guidance is that Atlantic and inland silverside are very difficult to distinguish without magnification, and the stated separators are anal-ray and scale counts. Those are not field observations.
    • Declared limitSources conflict on teeth: the Chesapeake Bay Program describes a small toothless mouth, the Smithsonian describes teeth well developed in bands. This record does not use teeth as a character.
    • Declared limitThe name “spearing” appears in no agency, Sea Grant or Smithsonian source consulted, so it is not offered here as sourced terminology.
    • Declared limitNo source consulted describes what a silverside school looks like from a beach, gives an eye-to-snout proportion, or states whether an adipose fin is present.
    • Size bandyoung-of-year: 25-76 mm
    • Size bandadult: 51-178 mm
    • Water typesurf
    • Water typeinshore
    • Water typenearshore
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitslarge schools close to the surface
    • Where it sitsover sandy bottom and grass beds in shallow estuaries and tidal creek mouths
    • Where it sitsalong the shoreline through the warm months, moving to deeper water in winter
    • How it movesschooling, close to the surface
    • How it movesmoves offshore in winter — one assessment records up to about ninety miles
    • Sources disagreeConnecticut's own size line is internally inconsistent as published: a state survey maximum of seven inches against a stated maximum reported elsewhere of 5.9 inches. The Smithsonian's 17.8 cm supports the larger figure.
    • Sources disagreeSpawning window differs by source — May to July in the Chesapeake Bay Program's account, late March through June in New York's, where it is also described as synchronised to full and new moons.
    • Sources disagree“Tidewater silverside” is applied to two different species by two approved sources: to Menidia beryllina by Connecticut and to Menidia peninsulae by the Smithsonian.

  • Anchovies →26 lines

    • What you can seeOne dorsal fin and a forked tail
    • What you can seeBody translucent — grey-shaded above, and light passes through the flank
    • What you can seeA narrow silver stripe along the middle of the side, often faint or absent toward the front
    • What you can seeLarge eye and a large mouth
    • What you can seeThe vent sits well forward, nearer the tips of the pelvic fins than the start of the anal fin
    • What argues against itTwo dorsal fins and a thick bright stripe is a silverside, not an anchovy
    • What argues against itA deep body with sharp belly scutes and a shoulder spot is menhaden or a herring
    • What argues against itNo pelvic fins and a dorsal running most of the back is a sand lance
    • What argues against itA faded stripe on a dead fish is not evidence against anchovy — the stripe is documented to fade after death
    • Declared limitThe snout is the character most often overstated. Florida describes the bay anchovy's snout as very short and only slightly overhanging the mouth, while NOAA's page for the Pacific northern anchovy describes a long snout overhanging a large mouth. A pronounced overhang is not what the sources say about the bay anchovy specifically.
    • Declared limitSpawning windows differ across three sources and only one attributes its window to a region.
    • Declared limitNo source consulted gives an eye-to-snout proportion for the bay anchovy, states whether an adipose fin is present, or describes what an anchovy school looks like from a beach.
    • Size bandyoung-of-year: 20-55 mm
    • Size bandadult: 51-178 mm
    • Water typesurf
    • Water typeinshore
    • Water typenearshore
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsdense schools in shallow open water
    • Where it sitsmore common over muddy bottom in brackish water shallower than twenty-five metres
    • Where it sitssaltmarsh creeks, marsh tide pools, eelgrass beds and the surf zone
    • How it movesdense schools
    • How it movesspawning takes place in the evening
    • How it movesadults move into the lower reaches of large rivers in spring and stay through summer
    • Sources disagreeAbundance is described very differently in two places: New York's assessment records a range-wide decline since the early 1990s and a tenfold drop in the Hudson, while the Chesapeake Bay Program still calls the bay anchovy the most abundant fish in that bay. Both can be true of different waters; neither is a statement about yours.

  • Menhaden (bunker, pogy) →33 lines

    • What you can seeSharp belly scutes, thirty to thirty-five of them, forming a distinct sawtooth keel
    • What you can seeA dark shoulder spot behind the upper edge of the gill cover
    • What you can seeRows of smaller spots behind the shoulder spot — up to six irregular horizontal lines
    • What you can seeOne dorsal fin at about the middle of the back, short and triangular
    • What you can seeDeeply forked tail, lower lobe slightly the longer
    • What you can seeLarge mouth with a projecting lower jaw, reaching at least under the back of the eye in adults
    • What argues against itA shoulder spot on its own does NOT separate menhaden from a young river herring — alewife and blueback both carry one, and alewife has belly scutes too. The rows of smaller spots behind it are what the sources actually separate on
    • What argues against itTwo dorsal fins and a bright thick side stripe is a silverside
    • What argues against itA translucent body with a narrow faint stripe and one dorsal is an anchovy
    • What argues against itNo pelvic fins and a dorsal running most of the back is a sand lance
    • What argues against itAn eye wider than the snout is long, on a fish with scutes and no trailing spot rows, points at alewife
    • Declared limitAdult size is stated five incompatible ways across NOAA, Maine, Connecticut, the Chesapeake Bay Program and VIMS, one of them exceeding another's stated maximum. The band here spans them rather than picking one.
    • Declared limit“Peanut bunker” has no sourced length. Massachusetts ties the term to young-of-year fish and gives no measurement; the only sourced juvenile thresholds are a NOAA developmental staging — larva under 30 mm, prejuvenile 30 to 38 mm, juvenile above 38 mm.
    • Declared limitNo consulted source separates Atlantic from Gulf menhaden by any character. The distinction in the literature is geographic.
    • Declared limitNo source consulted states whether an adipose fin is present, or gives an eye-to-snout proportion for Brevoortia.
    • Declared limitThe rows of smaller spots are described as a varying number, and up to six — they are not guaranteed present, least of all on a small fish.
    • Size bandyoung-of-year: 30-150 mm
    • Size bandadult: 152-500 mm
    • Water typesurf
    • Water typeinshore
    • Water typenearshore
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsvery large, tightly packed schools at or just under the surface
    • Where it sitsestuaries and tidal creeks in the warm months
    • Where it sitsyoung fish spend most of a first year inside estuaries
    • How it movesdense schools that ripple or splash at the water surface
    • How it movesyoung fish corralled at the surface or tight to the shoreline in a feeding blitz
    • How it movesswims with its mouth open, straining plankton through its gill rakers
    • How it movessynchronised swimming inside a dense school
    • Sources disagreeMigration is framed two ways. NOAA states that while many menhaden are migratory, others stay resident; the interstate commission describes a coastwide autumn migration of all sizes and ages south around the North Carolina capes.
    • Sources disagreeSpawning season conflicts: an October to March South Atlantic peak in the commission's account, against a two-mode pattern in VIMS — spring spawners in northern waters and autumn spawners from Long Island to North Carolina.
    • Sources disagreePelvic ray counts are published differently: seven rays in Connecticut's description, six branched rays in VIMS'. The two are reconcilable but are not stated the same way.

  • Shrimp (grass and penaeid) →25 lines

    • What you can seeA pointed, serrated blade over the eyes — the rostrum, with teeth along its edges
    • What you can seeGrass shrimp are near-transparent: the female's egg mass shows straight through the body
    • What you can seeColoured pigment in the eyestalks — orange in one common grass shrimp, yellow in the other
    • What you can seeClaws on the front walking legs, much smaller than a crayfish's
    • What you can seeSegmented body, flattened side to side, with a tail fan behind
    • What argues against itClaws on the first TWO pairs of walking legs is a grass shrimp; claws on the first THREE of five pairs is a penaeid shrimp — this is the cleanest separation any source states
    • What argues against itUnder about 13 mm, flattened side to side, swimming on its side and living on rather than in the bottom, points to an amphipod or scud
    • What argues against itA pair of pincers far larger than the walking legs, on a bottom animal that flicks backwards, is a crayfish
    • What argues against itAn egg-shaped shell with no claws at all is a mole crab, not a shrimp
    • Declared limitNo source consulted describes how a grass shrimp swims, hovers or escapes. The movement line here is the only behaviour any consulted source states.
    • Declared limitSize is stated two ways for the same animal: about 38 mm in the Chesapeake account and rarely larger than 50 mm in the South Carolina one. Different waters and different phrasings; the band spans both.
    • Declared limitNo source consulted states the family Palaemonidae, or a total leg-pair count for grass shrimp.
    • Declared limitThe claim that grass shrimp swarm or run on a particular tide in a way an angler can time is stated by no source consulted.
    • Size bandyoung-of-year: 10-38 mm
    • Size bandadult: 38-203 mm
    • Water typeinshore
    • Water typesurf
    • Water typenearshore
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsamong submerged grass beds, cordgrass and oyster shell
    • Where it sitsshallow estuarine water; grass shrimp move to warmer deeper water in winter
    • Where it sitson the bottom of wetlands and creeks rather than buried in it
    • How it movesamong the cordgrass at high tide, where transparency makes them nearly invisible
    • Sources disagreePopular usage increasingly writes these animals as Palaemon. No source consulted states that transfer, and USGS gives Palaemonetes as the currently accepted genus. This record keeps Palaemonetes.

  • Mole crab (sand flea) →26 lines

    • What you can seeNo claws or pincers anywhere you can see — it cannot bite or pinch
    • What you can seeRounded, smooth, white to grey or greenish carapace with small transverse ridges across the front
    • What you can seeTwo feathery antennae sitting below the eyes
    • What you can seeFive pairs of legs, the first without claws, the second flattened and paddle-like, the last three very short
    • What you can seeA short triangular tail — the telson — that does the digging
    • What you can seeFemales carry an orange egg mass tucked under the tail
    • What argues against itVisible claws, a wide spined shell and paddle-shaped back legs is a true crab, not a mole crab
    • What argues against itAntennae three times the length of the body belong to Lepidopa, a less common sand crab, not to Emerita
    • What argues against itSpines on the shell and legs point to the spiny mole crab rather than this one
    • What argues against itA body flattened side to side that swims on its side is an amphipod — the other animal people call a sand flea
    • Declared limitWhich Emerita is “the” sand flea differs by source and by place. Florida's wildlife agency profiles one species statewide and a Florida extension office names a different one for the panhandle. This record does not offer a species call from a photograph.
    • Declared limitSize figures conflict substantially for the same animal in the same state: up to two inches in one Florida source, half an inch to an inch in another. The band spans both rather than choosing.
    • Declared limitNo source consulted gives an Atlantic coastwise range, a spawning season, or a description of a freshly moulted mole crab.
    • Declared limitNo source consulted states a tide stage that concentrates mole crabs in a way an angler could fish. The only sourced statement is that they stay in the swash zone as the tide advances and retreats.
    • Size bandyoung-of-year: 5-13 mm
    • Size bandadult: 13-51 mm
    • Water typesurf
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsburied in wet sand in the swash zone of an open beach
    • Where it sitstracks the waterline up and down the beach as the tide moves rather than holding one spot
    • Where it sitsin the sand, not on it
    • How it movesburrows rear-first, tail and abdomen going in before the head
    • How it movespops up out of the sand, rides a wave, and burrows again
    • How it movesunfolds its antennae into the retreating wave to feed, then folds them back under the mouth
    • Sources disagreeThree sources credit the digging to three different parts in three different words — tail first, the telson, and the abdomen. They describe one rear-first motion at different levels of precision, but they are not the same wording.

  • Blue crab (young) →29 lines

    • What you can seeNine marginal teeth along each side of the shell, the ninth a strong lateral spine
    • What you can seeThree pairs of walking legs plus a rear pair flattened into paddles
    • What you can seeClaws bright blue; mature females carry coloured tips
    • What you can seeShell bluish to olive green
    • What you can seeThe apron on the underside is triangular on a juvenile, tapered on a male, broad and rounded on a mature female
    • What argues against itNo claws at all, an oval shell and rear-first burrowing is a mole crab
    • What argues against itA square shell with three spines a side, banded legs and red claw spots is an Asian shore crab — common and abundant on the Atlantic intertidal at exactly this size
    • What argues against itA rectangular shell with hairy legs and no purple claw spots points to a Pacific shore crab rather than a blue crab
    • Declared limitNo source consulted describes what a megalopa or a soft-shell crab actually looks like in the field, so this record cannot help you call either from a photograph.
    • Declared limitNo source consulted gives a family name, or a tide stage at which young crabs are most exposed.
    • Declared limitThe claim that shedder crabs concentrate on particular moons or tides in a fishable way is stated by no source consulted. Moult intervals are published in days and tied to size, not to the moon.
    • Size bandlarva: 2-5 mm
    • Size bandyoung-of-year: 5-76 mm
    • Size bandadult: 127-254 mm
    • Water typeinshore
    • Water typenearshore
    • Water typesurf
    • Life stagelarva
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsthe smallest instars settle into seagrass and stay there to about 25 mm across the shell
    • Where it sitsabove about 25 mm across, out onto unvegetated mud and sand flats near salt marsh
    • Where it sitson the bottom; burrowed into soft sediment in winter
    • How it movesswims with paddle-shaped back legs, and walks as well as swims
    • How it movesthe postlarval stage is carried back into the estuary by wind and tidal current rather than swimming there
    • How it movesstops feeding and burrows into sediment below about 50 degrees Fahrenheit
    • Sources disagreeMating season is given as May through October in the Chesapeake account and as two peaks, March to July and October to November, in the South Carolina one. Different latitudes plausibly explain it; neither source says so.
    • Sources disagreeLarval staging conflicts: six or more stages before the megalopa in one source, two planktonic stages in another. One appears to count instars and the other stage types, but no source reconciles them.
    • Sources disagreeMature female claw tips are red in three sources and bright orange in a fourth.

  • Marine worms (clam worm, sandworm, bloodworm) →25 lines

    • What you can seeA row of leg-like flaps down both sides, one pair to each segment, fringed with fine bristles
    • What you can seeAn eversible proboscis that shoots out of the mouth carrying dark jaws — TWO amber or black jaws on a clam worm or sandworm, FOUR black jaws on a bloodworm
    • What you can seeA bloodworm is pink to red throughout; a clam worm is brown in front, greener behind, with a red line of blood vessel down the back
    • What you can seeThe swarming form has enlarged eyes — especially the males, which turn bright red with a white tail
    • What you can seeThe nereid head carries short antennae, two fleshy palps, four eyes and four pairs of long whip-like feelers; the bloodworm head is a long ringed cone with four tiny antennae and nothing else
    • What argues against itA sucker at each end of the body is a leech, not a polychaete
    • What argues against itNo flaps down the sides at all, and no proboscis, points to an aquatic worm rather than a marine one
    • What argues against itA short, bright red, big-eyed worm swimming at the surface is NOT a different species from the long brown worm in the mud — it is the same animal in breeding form
    • Declared limitThe name “cinder worm” is used by no agency, Sea Grant or university source consulted. It appears only in angling media. The Smithsonian does establish that Nereis limbata and Alitta succinea are the same animal, which is the strongest link available — but no consulted source says the animal anglers call a cinder worm is that species.
    • Declared limitNo source consulted gives the families Nereididae or Glyceridae, or a segment count for the bloodworm.
    • Declared limitNo source consulted describes the swimming motion of a swarming worm beyond gyrating and circling.
    • Declared limitThe claim that the swarm fires on a specific moon phase, on the evening flood, at a stated water temperature in Fahrenheit, or for a set number of nights, is made by no source consulted. The temperature figures that exist are laboratory metamorphosis rates, not a field trigger.
    • Size bandadult: 100-400 mm
    • Size bandswarming form: 14-75 mm
    • Water typeinshore
    • Water typesurf
    • Water typenearshore
    • Life stageadult
    • Where it sitsin a broad U-shaped burrow in mud and sand, or in galleries of tunnels in soft sediment
    • Where it sitssome build permanent tubes on mud flats; others move freely across the shallows
    • Where it sitsduring a swarm they leave the bottom entirely and swim at the surface
    • How it movesswarming adults swim at the surface; males swim faster in a gyrating motion, females circling with males close behind
    • How it movesbreaks apart easily when handled, and regrows the lost part
    • Sources disagreeTwo authoritative sources disagree outright about the swarm. The Smithsonian's synthesis records swarming both by day and at night, documents no lunar or tidal relationship, and found no photoperiod effect in experiment; the Marine Biological Laboratory's account from Woods Hole says the swarming is regulated by the lunar cycle and that fertile worms can be collected only on summer nights. This record carries both and settles neither.
    • Sources disagreeThe only tidal statement in any consulted source — spawning in swarms on afternoon high tides — is about bloodworms, a different animal from the nereid worm anglers actually fish over.

  • Inshore squid →28 lines

    • What you can seeFins running at least half the length of the mantle — the character the longfin's name is built on
    • What you can seeEight arms plus two much longer tentacles with spoon-shaped, sucker-covered ends
    • What you can seeLarge eyes covered by a clear cornea
    • What you can seeTypically pink or orange, mottled with brown or purple, and changing as you watch
    • What you can seeA stiff internal shell — the pen — inside the mantle
    • What argues against itEight arms and no long tentacles is an octopus, not a squid
    • What argues against itA segmented body with flaps down the sides and no arms is a marine worm
    • What argues against itFins shorter than half the mantle rule out the longfin specifically, though this record does not attempt to name the other species
    • Declared limitNo source consulted states an arm and tentacle count for the longfin squid specifically. The eight-plus-two count is sourced as a general squid character and for the Pacific market squid.
    • Declared limitAtlantic and Pacific inshore squid are separated in the consulted literature by ocean, not by any character. No source consulted gives a morphological separator.
    • Declared limitNothing in the consulted sources describes what a squid looks like from the surface, in the surf or in an estuary. NOAA states plainly that market squid are rarely found in estuaries, bays or river mouths. If you are watching bait flush in a bay, this record cannot tell you it was squid.
    • Declared limitMaximum mantle length is published as over 40 to 50 cm, as 47 cm, and as 1.6 feet. Roughly consistent, but no one figure is offered as definitive.
    • Size bandlarva: 1-15 mm
    • Size bandyoung-of-year: 15-80 mm
    • Size bandadult: 80-490 mm
    • Water typenearshore
    • Water typeinshore
    • Water typeoffshore
    • Life stagelarva
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitson the bottom by day, dispersing up into the water column at night
    • Where it sitsyoung squid abundant in the upper ten metres over water fifty to a hundred and fifty metres deep
    • Where it sitsinshore in spring through autumn, offshore along the shelf edge for winter
    • How it movesshoots backwards by pumping water in through the open mantle and forcing it out through the funnel
    • How it moveschanges colour and pattern by expanding and contracting pigment cells in the skin
    • How it movesschools
    • Sources disagreeSpawning windows for the Pacific market squid differ between two sources that also name different regions: April to October in central California in NOAA's account, April to November in northern California in California Sea Grant's.

  • Mullet (young) →30 lines

    • What you can seeTwo well-separated dorsal fins, the first carrying four spines
    • What you can seeBlunt, flattened head with a small mouth at the front and a bump at the tip of the lower lip
    • What you can seeSeen from below, the mouth reads as an inverted V
    • What you can seeA thick adipose eyelid over part of the eye, visible to the naked eye by about 42 mm
    • What you can seeFaint horizontal stripes along the flank, formed by a dark spot at the centre of each scale — absent on small fish
    • What argues against itOne dorsal fin and a sawtooth belly keel is the herring family, which includes menhaden
    • What argues against itTwo dorsals but a slim body with an upturned mouth and a bright thick stripe is a silverside — one source separates them by the anal fin sitting directly under the dorsal on a mullet
    • What argues against itA black blotch at the base of the pectoral fin, with no stripes, points to white mullet rather than striped
    • What argues against itA rounded tail on a stout blunt-headed fish in a marsh creek is a killifish, not a mullet
    • Declared limitBelow about six inches, striped and white mullet are genuinely hard to separate. The sourced characters are eight versus nine soft anal rays, a gold spot on the gill cover of a living white mullet that fades fast after capture, and scales extending onto the second dorsal and anal fins of white mullet only.
    • Declared limitThe phrase “mullet run” is used by no source consulted. The autumn movement is real and sourced; the name is vernacular. So is “finger mullet”, which appears in no consulted source.
    • Declared limitWhy mullet jump has four different sourced explanations and no settled one. Connecticut's page says flatly: for unclear reasons.
    • Declared limitStripe onset is stated two ways — evident after 40 mm in one source, absent below about 150 mm in another. They cannot both describe the same transition and no source reconciles them.
    • Declared limitNo source consulted states whether mullet have belly scutes, a keel, or an adipose fin, or names the family.
    • Size bandyoung-of-year: 15-178 mm
    • Size bandadult: 330-698 mm
    • Water typesurf
    • Water typeinshore
    • Water typenearshore
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitshuge schools near the surface over sand or mud
    • Where it sitsclose to shore around the mouths of streams and rivers, in brackish bays, inlets and lagoons
    • Where it sitsjuveniles move inshore into tidal creeks at about an inch long
    • How it movesleaps clear of the water, sometimes a metre up — the habit the fish is named for in half its nicknames
    • How it movesschools by day for protection, though it feeds around the clock
    • How it movesadults feed by sucking in bottom sediment and scraping at grass
    • How it movesautumn movement toward and along the coast, which sources tie to north or northwest winds and cold fronts
    • Sources disagreeTwo sources contradict each other on where the second dorsal fin starts relative to the anal fin — over its beginning in Florida's wildlife agency page, behind it in the Florida Museum's. This record does not use that character.
    • Sources disagreeMaximum size is published as 698 mm in North Carolina, 914 mm internationally, 1200 mm by the Florida Museum and 1194 mm by Connecticut. Different scopes, not blended here.

  • Killifish (mummichog and striped killifish) →27 lines

    • What you can seeA single dorsal fin with no spines, and pelvic fins set well back near the anal fin
    • What you can seeFlattened head with the mouth tilted upward and the lower lip jutting past the upper
    • What you can seeRounded or squared-off tail — not forked
    • What you can seeMummichogs carry twelve to fifteen dusky vertical bars; breeding males darken and take on yellow and blue or orange in the fins
    • What you can seeStriped killifish are marked the other way round by sex: males carry fifteen to twenty vertical bars, females two or three irregular horizontal stripes
    • What argues against itA forked tail rules out killifish — every other small silver fish in the marsh has one
    • What argues against itTwo well-separated dorsal fins and a blunt head with a small terminal mouth is a young mullet
    • What argues against itA bright thick silver side stripe with two dorsals is a silverside
    • What argues against itHorizontal barring is not attributed to mummichogs of either sex by any source consulted; on a killifish it points to a female striped killifish
    • Declared limitNo source consulted compares killifish to young mullet or to silversides — the two look-alikes an angler actually faces in a marsh creek. One assessment notes striped killifish occur in mixed-species schools in intertidal pools, which makes this the largest gap in the record.
    • Declared limitNo source consulted states the striped killifish's dorsal fin count or tail shape. The single spineless dorsal is stated for the mummichog only.
    • Declared limitNo source consulted describes killifish behaviour at the water surface — only their position relative to the bank.
    • Declared limitNicknames like mud minnow and bull minnow appear in no consulted source.
    • Size bandyoung-of-year: 20-64 mm
    • Size bandadult: 64-203 mm
    • Water typeinshore
    • Water typesurf
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitsmuddy marshes, tidal creeks, grass flats and sheltered shores
    • Where it sitstight to the bank — one assessment measures a summer home range of 36 to 38 metres along one side of a creek
    • Where it sitsstriped killifish rarely more than a hundred yards from shore, and into the front of the beach
    • How it movesschools of a few fish to several hundred
    • How it movesa stranded striped killifish can flop head over tail across land for several yards to reach water
    • How it movesmummichogs burrow in mud or move deeper for winter; striped killifish burrow into sediment and stay
    • Sources disagreeMummichog barring by sex is contradicted inside one agency: its species gallery gives both sexes twelve to fifteen bars, while its own wildlife action plan supplement says breeding males have bars that females lack. Barring cannot be used as a sex character until that is resolved.
    • Sources disagreeMummichog maximum size is stated three ways — 12 cm, 17.8 cm, and five to six inches — by two agencies, one of them disagreeing with itself.

  • Sculpin →30 lines

    • What you can seeBroad, flattened, frog-like head with a large mouth
    • What you can seeLarge fan-shaped pectoral fins it props and scoots on
    • What you can seeNo scales — small prickles instead, and spines that can pierce a careless hand
    • What you can seeTwo dorsal fins, narrowly joined or nearly separate, the spines soft and flexible
    • What you can seeMottled brown to grey or green with dark blotches over body and fins; belly and pectorals sometimes tinted orange
    • What you can seeLateral line incomplete, stopping beneath the base of the second dorsal
    • What argues against itRough-edged scales and six or more stiff dorsal spines is a darter, not a sculpin
    • What argues against itChin barbels and a single adipose fin between the back fin and the tail is a catfish — a madtom or a young bullhead
    • What argues against itAbsence of a swim bladder does NOT separate sculpin from darters: sources state a darter's swim bladder is absent or much reduced too, and both sink and dash the same way
    • What argues against itNocturnal habit does not separate them either — madtoms forage at night as well
    • Declared limitThe most-repeated sculpin fact is the weakest separator. No swim bladder is true and well sourced, but a darter's is also described as absent or much reduced, so a sinking bottom fish is not automatically a sculpin. Scales, dorsal-spine stiffness and head width are the characters that actually work.
    • Declared limitOne agency notes slimy sculpin are sometimes mistaken for young burbot and gives no separating characters. Neither does any other source consulted.
    • Declared limitSize ceilings differ by source — about 4.5 inches for mottled sculpin, under five to six inches generally, usually under six inches. Compatible ranges, but no single number is offered.
    • Declared limitThe claim that sculpin suppress trout by eating trout eggs is not supported by the sources consulted. One state field guide reports bottom-dwelling aquatic insects at 99.7 percent of the diet, and a USGS diet study found fish eggs in only low numbers. No consulted source makes a population-level claim.
    • Size bandyoung-of-year: 20-50 mm
    • Size bandadult: 51-152 mm
    • Water typestream
    • Water typeriver
    • Water typespring
    • Water typelake-margin
    • Water typelake-open
    • Life stageyoung-of-year
    • Life stageadult
    • Where it sitson the bottom and under it — wedged among rocks, under cover, extremely cryptic
    • Where it sitsclear cold streams with gravel to cobble bottom and moderate to fast flow; spring branches
    • Where it sitsin the Great Lakes, on deep bottom — one survey finds peak abundance between fifty and ninety metres
    • How it moveslies motionless, then moves in short quick dashes
    • How it movesappears to hop along the bottom, scooting on the pectoral fins
    • How it movesnocturnal
    • How it movessinks when it stops swimming — there is no swim bladder to hold it up

  • Water boatmen →28 lines

    • What you can seeMouthparts form a broad triangular beak rather than chewing jaws — this is what makes it a bug and not a beetle
    • What you can seeFlat back ruled across by several narrow dark parallel lines
    • What you can seeFront feet shaped like scoops and fringed with hairs
    • What you can seeOne pair of long, flattened, oar-like hind legs
    • What you can seeA thin silvery bubble of air trapped against the body, carried under like a diving bell
    • What you can seeAntennae short and hidden beneath the eyes
    • What argues against itSwimming belly-up rules out a boatman — that is a backswimmer
    • What argues against itA back keeled like a boat hull, with no crosslines, is a backswimmer
    • What argues against itHard wing covers meeting in a straight seam, visible threadlike antennae and chewing mouthparts is a diving beetle
    • What argues against itA bite means you are not holding a water boatman. Sources call it one of the few aquatic true bugs that is not a predator and does not bite
    • Declared limitSize is stated three incompatible ways — usually under half an inch, about five millimetres, and a coarse bracket class running to 29 mm. The band spans them.
    • Declared limitWater boatmen are described as not predaceous and then immediately qualified: a few species do eat small aquatic animals. Almost all, not all.
    • Declared limitThe common claim that boatmen carry their air under the wing covers while backswimmers carry it in belly channels is supported by no source consulted. Both are described identically.
    • Declared limitNo source consulted states whether corixids row with alternating or simultaneous leg strokes, so stroke pattern cannot be used to separate them from a diving beetle.
    • Size bandnymph: 2-8 mm
    • Size bandadult: 5-13 mm
    • Water typelake-margin
    • Water typereservoir
    • Water typestream
    • Water typeriver
    • Water typespring
    • Life stagenymph
    • Life stageadult
    • Where it sitsponds and quiet corners of lakes and streams, clinging to submerged vegetation
    • Where it sitsa backswimmer rests tilted head-down at the surface with the tip of its abdomen through the film
    • How it movesrows with long oar-like hind legs fringed with fine hairs
    • How it movesswims the right way up, back uppermost
    • How it movesswims jerkily; flies strongly and comes to lights at night; clumsy out of water

  • Backswimmers →29 lines

    • What you can seeSwims on its back, belly upwards — two independent sources state it, and it is the settled answer
    • What you can seeBack keeled like a hull, with no crosslines across it
    • What you can seePiercing, tube-like mouthparts — a beak, not chewing jaws
    • What you can seeLarge dark red eyes
    • What you can seeFront and middle legs built for grasping; hind legs long and oar-like
    • What you can seeA thin silvery bubble of air trapped against the body
    • What argues against itSwimming right way up, with a flat back ruled by dark parallel crosslines and scoop-shaped front feet, is a water boatman
    • What argues against itHard wing covers meeting in a straight seam, with threadlike antennae you can see, is a diving beetle
    • What argues against itHead-down at the surface with the tail tip out of the water does NOT settle it — a diving beetle rests in exactly the same posture, and sources describe both that way
    • What argues against itCarrying a silvery air store does not settle it either. Both bugs and diving beetles do it
    • Declared limitSize is stated three incompatible ways — usually under half an inch, about 13 mm, and a bracket class of 15 to 29 mm. The band spans them.
    • Declared limitThe most detailed account consulted covers a Eurasian species. Its air-film duration, temperature behaviour and one-brood-a-year seasonality are not offered here as North American facts.
    • Declared limitNo source consulted states that backswimmers are important forage for fish. The same source describes them eating fish eggs and fry, which is the food web running the other way — worth knowing before you tie one on.
    • Declared limitNo source consulted describes whether they row with alternating or simultaneous strokes.
    • Size bandnymph: 2-10 mm
    • Size bandadult: 10-29 mm
    • Water typelake-margin
    • Water typereservoir
    • Water typestream
    • Water typeriver
    • Water typespring
    • Life stagenymph
    • Life stageadult
    • Where it sitsponds and quiet corners of lakes and streams, clinging to submerged vegetation
    • Where it sitsa backswimmer rests tilted head-down at the surface with the tip of its abdomen through the film
    • How it movesrows with long oar-like hind legs, belly upwards
    • How it movesrests tilted head-down at the surface with the tip of the abdomen through the film
    • How it moveswaits in ambush, usually part-way up a plant stem
    • Sources disagreeHow badly a backswimmer bites differs by source: painful if mishandled in one state field guide, very rare and usually the result of rough handling in a university extension account. Both agree it takes handling.

  • Cranefly larvae →25 lines

    • What you can seeNo legs at all — flies are the only aquatic insect order whose larvae lack fully developed legs
    • What you can seeThe rear end finishes in a disc ringed by fleshy lobes or tentacle-like projections
    • What you can seeFleshy welts on the underside of some abdominal segments — swellings, not hooked prolegs
    • What you can seeA rounded head capsule that is present but usually withdrawn into the body and hard to see
    • What you can seeVery small hairs along either side, and a translucent skin with the gut line visible inside
    • What argues against itA hard dark head clearly sticking out in front, on a thin worm-like body with two pairs of hook-tipped prolegs, is a midge larva. Bright red also points to a midge
    • What argues against itNo head, thorax or abdomen distinction at all, with bristle bundles along the whole body, is an aquatic worm
    • What argues against itThree pairs of segmented legs rules out every fly larva
    • What argues against itSize does not separate cranefly from midge or from aquatic worm; neither does habitat. Use the head and the tail end
    • Declared limitSources disagree about the head. One state field guide says the larvae possess a definite head; a state assessment guide says the head capsule is often reduced, barely visible, and retracts so far that seeing it usually means cutting the thorax open. This record follows the second, and says so.
    • Declared limitSize brackets conflict substantially — 10 to 17 mm, 13 to 25 mm, 29 to 50 mm, and under 5 to over 50 mm, three of those from one agency's own publications.
    • Declared limitNo source consulted describes how cranefly larvae move, places them in the drift, or states that fish eat them. The angling picture of a cranefly larva tumbling helplessly down a riffle is supported by nothing consulted here. That is a real gap in a forage guide and is left visible rather than filled.
    • Declared limitNo source consulted describes gills, or names the tail structure a spiracular disc.
    • Declared limitThe name “leatherjacket” appears in no consulted source.
    • Size bandlarva: 5-50 mm
    • Water typestream
    • Water typeriver
    • Water typelake-margin
    • Water typespring
    • Water typereservoir
    • Life stagelarva
    • Where it sitson and in the substrate, where decaying vegetation and leaf debris collect
    • Where it sitsa crawler and burrower, in habitats from lakes and wetlands to fast water
    • How it movesclassified as a crawler and burrower; no source consulted describes how it actually moves
    • Sources disagreeHead visibility is a straight contradiction between two agencies, and it is the single character a beginner would reach for first.

  • Aquatic sowbug (aquatic isopod) →22 lines

    • What you can seebody flattened top to bottom, so it lies flat in a wet hand with its back uppermost
    • What you can seeseven pairs of walking legs, all of them much the same
    • What you can seetwo pairs of antennae, one pair conspicuously long
    • What you can seeno wings, no wing pads and no tail filaments
    • What argues against ita body flattened side to side, lying over on its flank, is a scud rather than a sowbug
    • What argues against ita C-curved body that flicks and darts is a scud
    • What argues against itthree pairs of legs, or any wing pads, put the animal among the insects
    • What argues against itpincers on the front legs point to a crayfish
    • Declared limitA sowbug result is the family level. It does not separate Caecidotea from Asellus, and it does not distinguish a surface-water animal from a groundwater one.
    • Declared limitSize is not a stage cue here: every stage looks the same, so a 6 mm animal and a 19 mm animal are the same shape and tell you nothing about age.
    • Declared limitSowbugs are crawlers rather than behavioural drifters. This record says nothing about when one would be available in the drift.
    • Size bandadult: 5-20 mm
    • Water typespring
    • Water typestream
    • Water typeriver
    • Water typelake-margin
    • Life stageadult
    • Where it sitsunder rocks, wood and debris on the bottom
    • Where it sitsamong sediment and vegetation in seeps and spring branches
    • How it movesslow deliberate crawl over rock and wood
    • How it movesdoes not swim in open water
    • How it movesstays flat and stable rather than rolling onto its side

  • Freshwater snail →22 lines

    • What you can seeone coiled shell, with a soft foot coming out of it
    • What you can seethe animal grazes over rock, wood and plants rather than swimming
    • What you can seegilled snails carry a horny trapdoor (operculum) that seals the shell mouth when the animal withdraws
    • What argues against ittwo hinged halves that close is a clam, not a snail
    • What argues against ita tube of glued sand, sticks or pebbles with a jointed head and legs coming out of it is a cased caddis
    • What argues against ita soft contractile body with a sucker at each end is a leech
    • What argues against itlegs of any kind rule out a snail
    • Declared limitThis is 'snail' and nothing finer. The gilled/lunged split turns on an operculum that is only visible when the animal is withdrawn and is marginal to see on a shell half an inch across, so this record does not attempt it.
    • Declared limitIt cannot tell a native snail from an invasive one. A New Zealand mudsnail is about 5 mm and is not identifiable in the hand.
    • Declared limitSnails have no emergence, so this record carries no timing information at all.
    • Size bandadult: 2-45 (most under 20) mm
    • Water typespring
    • Water typestream
    • Water typeriver
    • Water typelake-margin
    • Water typelake-open
    • Water typereservoir
    • Life stageadult
    • Where it sitsgrazing on rock, wood and plant stems
    • Where it sitspulmonates come up to the film to take air
    • How it movesglides slowly on a muscular foot
    • How it movesfalls rather than swims when dislodged

  • Clam (small freshwater bivalve) →22 lines

    • What you can seetwo hinged shell halves you can see the seam of, and feel close
    • What you can seeno head, no legs, no antennae
    • What you can seeconcentric growth ridges on the shell
    • What argues against ita single coiled shell is a snail
    • What argues against ita case of glued grit with an insect head and legs coming out of it is a cased caddis
    • What argues against ita thick, heavy, strongly ridged shell points away from a fingernail clam and toward an Asian clam or a young mussel
    • Declared limitThis record is honest at 'small bivalve' and no finer. Telling a fingernail clam from a juvenile Asian clam or a juvenile mussel rests on shell sculpture at five millimetres, which is a magnification character and not a field one — and that is the distinction with the ecological weight, because it is the native/invasive one.
    • Declared limitBivalves have no emergence and no hatch, so this record carries no timing information.
    • Declared limitA clam is buried, immobile forage. Recording one tells you about the substrate you are standing on rather than about what is in the drift.
    • Size bandadult: 3-15 for fingernail and pea clams; juvenile mussels overlap this range mm
    • Water typespring
    • Water typestream
    • Water typeriver
    • Water typelake-margin
    • Water typelake-open
    • Water typereservoir
    • Life stageadult
    • Where it sitsat or just under the bottom substrate
    • Where it sitssand, gravel and mucky bottoms
    • How it movesploughs slowly through sediment on a muscular foot
    • How it movesclamps shut when handled
    • How it movesdoes not swim or drift

  • Alderfly larva →23 lines

    • What you can seea single tail filament pointing straight back from the tip of the abdomen
    • What you can seeseven pairs of pointed lateral filaments along the sides of the abdomen, with no cottony gill tufts at their bases
    • What you can seelarge forward-projecting jaws on a hardened head
    • What you can seefound in soft, quiet, silty pockets rather than fast cobble
    • What argues against ita pair of hooked prolegs at the rear instead of one filament, with cottony gill tufts along the abdomen, is a hellgrammite
    • What argues against itthree tails point to a mayfly nymph; two tails with wing pads point to a stonefly
    • What argues against ita portable case or a fixed net points to a caddis
    • What argues against ita wormlike body with no thoracic legs points to a midge or cranefly larva
    • Declared limitThe pupa is terrestrial. Alderflies crawl out of the water and pupate ashore in soil or rotten wood, so there is no aquatic pupal drift and nothing hatches off the surface — the value of this record is as year-round subsurface forage, not as a hatch.
    • Declared limitA group-level call does not give the species, and emergence timing is species-dependent and happens out of the water where an angler will not see it.
    • Declared limitIt does not tell you the instar. This larva can be 5 mm or 25 mm and looks the same at both.
    • Size bandlarva: 5-25 mm
    • Size bandadult: body 10-20 mm
    • Water typestream
    • Water typeriver
    • Water typelake-margin
    • Water typelake-open
    • Life stagelarva
    • Life stageadult
    • Where it sitssilt-bottomed pools and quiet sections
    • Where it sitssoft detritus in lakes and ponds
    • How it movescrawls and burrows in silt and detritus
    • How it movesundulates the abdomen when swimming, but is not an open-water animal

  • Black fly larva →26 lines

    • What you can seea swollen rear end gripping the substrate, so the body stands up and waves downstream
    • What you can seedense colonies on one rock, all bending the same way in the current
    • What you can seea hardened rounded head, with a pair of brush-like fans on larger larvae
    • What you can seeno jointed thoracic legs — a single proleg at the front
    • What argues against ita wormlike larva of even diameter with no swollen rear, free-living or in a soft tube, is a midge
    • What argues against ita stone or stick case, or a fixed silk net, points to a caddis
    • What argues against itjointed thoracic legs rule out a black fly larva
    • What argues against itstill water points away from this group; these are animals of flowing water
    • What argues against ita plump legless grub with a rear disc ringed by fleshy lobes is a cranefly larva
    • Declared limitA group-level call is the family. It does not give the genus, and genera differ in seasonality, so this record does not date the observation.
    • Declared limitIt does not give the instar, and instar matters here: 5 mm and 15 mm are a threefold difference in imitation size.
    • Declared limitThe family spans a broad tolerance range, so finding these tells you the water is flowing over stable substrate and very little about its quality.
    • Size bandlarva: 5-15 mm
    • Size bandpupa: 4-8 mm
    • Size bandadult: 2-5 mm
    • Water typestream
    • Water typeriver
    • Life stagelarva
    • Life stagepupa
    • Life stageadult
    • Where it sitsattached rear-first to rock, wood and trailing weed in current
    • Where it sitsin dense colonies on the same stone
    • How it movesanchored and filtering rather than swimming
    • How it movesmoves by an inchworm looping gait
    • How it movesrelocates by paying out a silk thread and drifting on it
    • Sources disagree[object Object]

The pages themselves

All 166, and what each one is holding up.

Next