Mutton Snapper: water temperature and season

Reef edges, and spawning runs after the spring and summer full moons. Anglrithm scores mutton snapper at reef and offshore spots, on the Atlantic, in the Keys and on the southwest Gulf coast. This page sets out what that score weighs and the cited studies behind it.

Water temperature

Evidence tier Well established

The score carries no water temperature factor for mutton snapper.

Season

Best Apr to Jun, by the score's season weight.

When they spawn

Spawning months on record: Apr, May, Jun and Jul. A calendar from the studies linked, months and moon only, never a site; not a catch forecast.

The score's season weight by month, from the studies cited in the species profile; the outlined months are at 90% of its peak or better.

What the score weighs

  • SeasonWell establishedkeeps 100%
  • CurrentSmall real effectkeeps 50%
  • TideReal, but localkeeps 100%
  • WindSmall real effectkeeps 50%
  • SeasSmall real effectkeeps 50%
  • MoonSmall real effectkeeps 50%
  • LightReal, but localkeeps 100%
Why each tier
  • Season: Season is the strongest single predictor in most recreational datasets, because it carries water temperature, migration and spawning together. Shaw et al. 2021, PLOS ONE 16:e0257882.
  • Current: No study we found ties a current speed or direction to catch for any fish in this app. Current decides whether you can hold a bait where you want it and how a drift sets up: off Southeast Florida the Gulf Stream runs fast close to the coast, and deep-drop boats stay under power to hold position. Treat a current pattern as a fact about your fishing more than about the fish. Davis, Cudney & Blankinship 2017, Bulletin of Marine Science 93:539-555. Lerner et al. 2013, Transactions of the American Fisheries Society 142:95-104.
  • Tide: Tide moves fish through cuts and over structure, and the effect can be strong at a particular spot. It is not a species-wide rule: the published work finds the pattern flips by species, site and season, and one high-velocity channel study found no link to current speed at all. Trust it where you fish; do not trust it as a fact about the fish. Becker et al. 2016, Estuaries and Coasts 39:1199. Milardi et al. 2018, ECSS. Viehman & Zydlewski 2017, PLOS ONE 12:e0176405.
  • Wind: Wind has a measurable effect on fish movement, apparently through dissolved oxygen, but it is small. The larger effect in any personal log is on you: wind decides where you can fish and whether you go at all, so a wind pattern in your own data is at least as likely to be about your choices as about the fish. Milardi et al. 2019, Aquatic Ecology 53:251-263. Shaw et al. 2021, PLOS ONE 16:e0257882.
  • Seas: Sea state mostly decides whether the trip happens and whether you can fish it well. Treat a sea-state pattern in your own log as a fact about your fishing, not about the fish. No direct angling-scale study found; labelled from mechanism.
  • Moon: Moonlight genuinely times spawning in many species through melatonin and clock genes, which is why aggregations key to the moon. For whether today is a good day, the measured effect is real but tiny, smaller than temperature and far smaller than where you fish. Ikegami et al. 2014, Marine Genomics 14:59-66. Shaw et al. 2021 found lunar effects significant but Cohen d below 0.20.
  • Light: Dawn and dusk are well documented as movement and feeding windows for many inshore and coastal species, and the effect interacts with tide rather than standing alone. Viehman & Zydlewski 2017, PLOS ONE 12:e0176405.

Each factor's weight is multiplied by its evidence tier: well established and real but local keep all of it, a small real effect keeps half, and a popular belief that is not supported keeps a fifth. Guidance from the studies sits beside the score, never in it.

Rules and depth

  • Released mutton snapper seen by charter observers: in the Keys 76.5% came from 0 to 30 ft; off Southeast Florida 92.3% came from 66 to 128 ft. Lazarre 2023

Seasons, sizes and bag limits change: check the FWC saltwater regulations before you keep a fish.

From the research programs

  • In the Gulf of America, mutton snapper spawn from May through August. GCOOS, no date (Gulf of America, outside South Florida)
  • Muttons gather the week before the full moon and usually spawn 2 to 5 days after it, late afternoon, in 33 to 98 ft. GCOOS, no date (Gulf of America, outside South Florida)The score's moon factor for mutton is labelled not supported and discounted; this line is spawning timing, not a catch rate.
  • Adult muttons may travel 216 nm or more to reach shelf-edge spawning sites. GCOOS, no date (Gulf of America, outside South Florida)
  • Mutton snapper rank among the most frequently shark-depredated species in Florida; 43 percent of surveyed anglers reported depredation. FAU, 2025
  • Bull and sandbar sharks were the top identified depredators; the Keys, southeast and southwest Florida saw the most events, peaking in spring. FAU, 2025

Findings in our own words from the programs linked, area and season only; cited, not endorsed. None of these lines is in the score.

The studies

  • Southeast Florida reefs hold fewer species and fewer young target fish than protected reference reefs; adult target fish are scarce in the Keys too.

    SE Florida; Florida Keys; Dry Tortugas · field · full text read

    Grove et al. 2024

  • During two Category 5 hurricanes, tagged nearshore fish shifted briefly toward deeper water, but most stayed in the bay for months.

    US Virgin Islands (out of region) (outside South Florida) · field · full text read

    Matley et al. 2019

  • Lower Keys snapper spawning runs mutton May-June, then cubera and gray snapper July-August, mostly on 12-37 m reef.

    Lower Florida Keys · survey · full text read

    Lindeman et al. 2000

  • Per trip, east Florida yellowtail peak September-October, gray snapper late summer, and mutton in winter.

    Florida Atlantic coast (MRIP South Atlantic Florida, excludes Monroe County) · agency · agency document

    NOAA Fisheries Marine Recreational Information Program 2025

  • In Florida's Gulf plus Keys domain, dolphin catch per trip peaks July-August and blackfin and wahoo peak September-October.

    Florida Gulf coast including Monroe County (Keys) as one MRIP domain · agency · agency document

    NOAA Fisheries Marine Recreational Information Program 2025

  • Anglers fishing reef-type bottom in Biscayne National Park caught a mutton snapper on about 1 in 7 trips; most trips caught none.

    Biscayne National Park · agency · agency document

    Muller 2023

  • Keys charter boats catch most mutton snapper shallower than 10 m; SE Florida boats catch them mostly at 20-39 m.

    Florida Keys; SE Florida · agency · agency document

    Lazarre 2023

  • About one in four released mutton snapper on for-hire trips shows impairment or deep hooking; deeper SE Florida fish are vented more.

    Florida Keys; SE Florida · agency · agency document

    Lazarre 2023

The whole evidence library

Entries read in full text or published by an agency. Entries read only in their abstract are listed on the science page with their numbers withheld.

Where it is scored

Today's score at any of them is free with an account; every fish has a page like this one.

Display only, not for navigation. Every figure here names its source; check the NWS marine forecast and the posted rules before you leave the dock.