Evidence
Where all of this came from.
39 reference records rest on 224 published pages, and 109 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. Every reviewed line sits behind a record or a search, with the sources standing behind its record.
How to read this
A line is cited as precisely as someone checked it.
Where a reviewer traced a line to the pages that carry it, the line names those pages and, when the evidence is narrower than the record, where it comes from — one coast, one lake, one region. 605 of 1049 of the lines below are traced that way. The rest show the sources standing behind their whole record, marked “record’s sources”, because nobody has yet checked which page carried which line, and printing a single citation there would be a mapping nobody made.
National
52
A federal or national government body — USGS, NOAA, EPA, the Fish and Wildlife Service, the Park Service, Fisheries and Oceans Canada.
State
109
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
45
A university research programme, cooperative extension service or Sea Grant office. Published work, but not the agency that manages the water.
Journal
6
A peer-reviewed paper, or a curated scientific register such as the World Register of Marine Species. Added with the 2026-09-25 evidence review, which went to the primary study where no agency page said what a claim needed.
Probe leftovers
What the weekly check could not treat as ordinary.
These addresses are still the citations. The check named what it saw. None of them is a gone page in the MISIN sense, so the records were not rewritten to hide a redirect, a timeout, or a bot wall.
Iowa DNR — BluegillMoved
The cited address answers through a permanent redirect. GET on the page that lands still names Bluegill.
A same-site move that still names the animal is not the MISIN case. The citation stays until a reviewer reads the new address into the record.
CASG — market squidUnreachable from this network
The California Sea Grant market-squid page times out from the probe network.
NOAA still covers the same animal on this record. The CASG address stays; a timeout is not a reason to drop a citation.
Mass.gov — menhaden and longfin squidRefused the probe
Both creature-feature pages answered 403 from the probe network.
A bot wall is not evidence the page is gone. The citations stay; the weekly check does not fail the build on unverifiable.
Michigan DNR — crayfish identification PDFRefused the probe
The cited PDF answered 403 from the probe network.
A refused PDF is not a 404. The citation stays on the crayfish record until a reviewer can open it.
Smithsonian Tropical Research Institute — silversidesRefused the probe
The Menidia page answered 500 from the probe network.
A 500 is not a 404, and it is not a 403. The citation stays.
Claims
Every reviewed line in the app.
Shad (gizzard and threadfin) →30 lines
- What you can seeSharp-edged scutes along the midline of the belly give a sawtooth keel you can feel by running a finger forwardMDC-GIZZARD-SHAD, IOWA-DNR-GIZZARD-SHAD
- What you can seeLast dorsal ray is drawn out into a long trailing filament — the single most useful character in this groupMDC-GIZZARD-SHAD, USGS-NAS-GIZZARD-SHAD, IOWA-DNR-GIZZARD-SHADEvidence from: Gizzard and threadfin shad (Dorosoma)
- What you can seeIn gizzard shad, a blunt snout with a small inferior mouth; the upper jaw projects beyond the lowerTPWD-GIZZARD-SHAD, USGS-NAS-GIZZARD-SHAD, IOWA-DNR-GIZZARD-SHADEvidence from: Gizzard shad only; threadfin has a pointed snout
- What you can seeDark shoulder spot behind the upper edge of the gill cover, strongest on young fish; it may be faint or absent on large adultsIOWA-DNR-GIZZARD-SHAD, MDC-GIZZARD-SHAD
- What you can seeDeeply forked tail and a deep, slab-sided silvery bodyMDC-GIZZARD-SHAD, IOWA-DNR-GIZZARD-SHAD
- What you can seeOne dorsal fin of 10 to 12 soft raysIOWA-DNR-GIZZARD-SHADEvidence from: Gizzard shad
- What argues against itAn adipose fin between dorsal and tail points to cisco or a smelt, not to shadDFO-BAITFISH-PRIMER, MANITOBA-BAITFISH-GUIDE
- What argues against itNo trailing dorsal filament points to alewife or another Alosa herring, not to shadMDC-GIZZARD-SHAD, ILDNR-ALEWIFE
- What argues against itA spiny front dorsal fin rules shad out — the shad dorsal is a single fin of soft raysIOWA-DNR-GIZZARD-SHAD, MDC-GIZZARD-SHAD
- What argues against itThreadfin shad are separated from gizzard shad by yellow fins and a black-speckled chin and mouth floor; agency pages disagree on which jaw projects, and this record does not try to split them in the fieldUSGS-NAS-GIZZARD-SHAD, MDC-GIZZARD-SHAD, MDC-THREADFIN-SHAD, ILDNR-THREADFIN-SHADEvidence from: Threadfin vs gizzard shad
- Declared limitThis record covers gizzard and threadfin shad together. Anal-ray and scale counts on a fish in hand separate them reliably; yellow fins and a black-speckled chin on a live threadfin are field hints.MDC-GIZZARD-SHAD, USGS-NAS-GIZZARD-SHAD, MDC-THREADFIN-SHAD
- Declared limitShad are cold-sensitive and winter die-offs are a documented natural event in the Midwest, not a sign of pollution.INDNR-SHAD-DIEOFF, USGS-NAS-GIZZARD-SHADEvidence from: Midwest winters; higher latitudes
- Declared limitAdult gizzard shad grow beyond the size most gamefish will take; young-of-year fish are the forage-relevant stage.MDC-GIZZARD-SHAD, SCDNR-GIZZARD-SHAD
- Declared limitThreadfin shad are much smaller than gizzard shad, rarely over about 150 mm, and can spawn in their first summer; an adult threadfin falls inside the young-of-year size band here.MDC-GIZZARD-SHAD, MDC-THREADFIN-SHAD, ILDNR-THREADFIN-SHADEvidence from: Threadfin shad (Dorosoma petenense)
- Size bandyoung-of-year: 30-180 (100-180 by the end of the first year) mmUSGS-NAS-GIZZARD-SHAD, MDC-GIZZARD-SHAD, TPWD-GIZZARD-SHADEvidence from: Gizzard shad; end-of-year size in productive waters
- Size bandadult: 229-520 (gizzard shad, commonly 229-356) mmMDC-GIZZARD-SHAD, USGS-NAS-GIZZARD-SHAD, TPWD-GIZZARD-SHADEvidence from: Gizzard shad only; adult threadfin are smaller (see limitation)
- Water typereservoirrecord’s sources
- Water typelake-openrecord’s sources
- Water typeriverrecord’s sources
- Water typelake-marginrecord’s sources
- Life stageyoung-of-yearrecord’s sources
- Life stageadultrecord’s sources
- Where it sitsnear surface in large moving schoolsMDC-GIZZARD-SHAD
- Where it sitsopen water of reservoirs and large riversMDC-GIZZARD-SHADEvidence from: Missouri
- Where it sitsshoreline and open water both usedSCDNR-GIZZARD-SHADEvidence from: South Carolina reservoirs
- How it movesconstantly moving schoolsrecord’s sources
- How it movesleaping or skittering across the surface when pressedMDC-GIZZARD-SHAD, TPWD-GIZZARD-SHAD
- How it movesmost active at dusk and at nightMDC-GIZZARD-SHADEvidence from: Gizzard shad
- Sources disagreeThreadfin shad jaw position is described both ways. Missouri Department of Conservation's gizzard shad page and the USGS Nonindigenous Aquatic Species table say the threadfin's lower jaw projects; Missouri's own threadfin page and Illinois DNR say its upper jaw projects beyond the lower. Neither is used as a field character here.record’s sources
- Sources disagreeGizzard shad spawning dates differ by source and region. Missouri Department of Conservation gives early April through May; the USGS Nonindigenous Aquatic Species profile gives mid-May to mid-June; South Carolina DNR says March through August.record’s sources
- Missouri Department of ConservationMDC-GIZZARD-SHAD · State · read 2026-09-02
- U.S. Geological Survey Nonindigenous Aquatic SpeciesUSGS-NAS-GIZZARD-SHAD · National · read 2026-09-02
- Iowa Department of Natural Resources BioNetIOWA-DNR-GIZZARD-SHAD · State · read 2026-09-02
- Texas Parks and Wildlife DepartmentTPWD-GIZZARD-SHAD · State · read 2026-09-02
- South Carolina Department of Natural ResourcesSCDNR-GIZZARD-SHAD · State · read 2026-09-02
- Indiana Department of Natural ResourcesINDNR-SHAD-DIEOFF · State · read 2026-09-02
- Missouri Department of ConservationMDC-THREADFIN-SHAD · State · read 2026-09-25
- Illinois Department of Natural ResourcesILDNR-THREADFIN-SHAD · State · read 2026-09-25
- Fisheries and Oceans CanadaDFO-BAITFISH-PRIMER · National · read 2026-09-02
- Manitoba Natural Resources and Northern DevelopmentMANITOBA-BAITFISH-GUIDE · State · read 2026-09-02
- Missouri Department of ConservationMDC-GOLDEN-SHINER · State · read 2026-09-02
- Illinois Department of Natural ResourcesILDNR-ALEWIFE · State · read 2026-09-25
- Illinois Department of Natural ResourcesILDNR-CISCO · State · read 2026-09-02
- Maine Department of Marine ResourcesMAINE-DMR-ALEWIFE · State · read 2026-09-02
The pages themselves
All 224, and what each one is holding up.
- Fisheries and Oceans Canada
DFO-BAITFISH-PRIMER
- Illinois Department of Natural Resources
ILDNR-ALEWIFE
- Illinois Department of Natural Resources
ILDNR-CISCO
- Illinois Department of Natural Resources
ILDNR-THREADFIN-SHAD
- Indiana Department of Natural Resources
INDNR-SHAD-DIEOFF
- Iowa Department of Natural Resources BioNet
IOWA-DNR-GIZZARD-SHAD
- Maine Department of Marine Resources
MAINE-DMR-ALEWIFE
- Manitoba Natural Resources and Northern Development
MANITOBA-BAITFISH-GUIDE
- Missouri Department of Conservation
MDC-GIZZARD-SHAD
- Missouri Department of Conservation
MDC-GOLDEN-SHINER
- Missouri Department of Conservation
MDC-THREADFIN-SHAD
- South Carolina Department of Natural Resources
SCDNR-GIZZARD-SHAD
- Texas Parks and Wildlife Department
TPWD-GIZZARD-SHAD
- U.S. Geological Survey Nonindigenous Aquatic Species
USGS-NAS-GIZZARD-SHAD
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