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The life cycle of common snook

Common snook, Centropomus undecimalis is one of five snook species found in Florida and the only one we see here in southwest Florida.

Where they live

Snook occur from South Carolina to Brazil, including Florida to Texas along the Gulf of Mexico. They can live in most any habitat, provided they have moderate to good water quality and water temperatures that generally stay above 60 degrees Fahrenheit. Snook are euryhaline, meaning they can move freely between fresh and salt water. But that doesn’t mean they count as freshwater fish. If you are targeting them, you need a saltwater fishing license.


Snook are protandrous hermaphrodites, meaning males may change to females as they age. This transition takes place when snook are between one and seven years, or 12-35 inches in total length. The transition happens quickly and is identified by both male and female sex cells present in the gonads. In transitioning snook, female gonads mature directly from male gonads shortly after spawning. As such, it’s possible for snook to spawn once as a male and then again as a female within the same season.

Snook spawning occurs between April and October, with peek spawning during long day light days in June and July. During this time, snook congregate in spawning areas. Salinity is important for spawning snook. Saltwater is dense, making eggs buoyant. The more buoyant the environment, the greater chance of eggs and newly hatched larvae getting carried to suitable habitats.

Once spawning begins, a snook can spawn every other day, releasing 1.5 million eggs each spawn. Snook spawning typically occurs during a new or full moon. Released eggs hatch after about 28 hours. Newly hatched larvae drift towards the closest estuary on incoming tides, where they settle out after finding suitable habitat.

Early life stage

During the early life, baby snook seek quiet back bay waters away from predators

In their early life stages, snook prefer low salinity to freshwater backwater habitats with an adequate supply of planktonic insects, molly’s and mosquito fish to prey on. They require dense, overhanging vegetation or emergent plants to protect them from birds and other predators, and prefer quiet, sheltered areas with little to no flow. At this early stage, snook have physiological adaptations that allow them to tolerate low oxygen waters. Few fish can endure low oxygen conditions, affording young snook refuge from many fish predators.

After about a year, snook must move out to the lower estuary. They are now losing their tolerance for low oxygen conditions and require larger food prey. At around 10-12 inches in size, snook are found in the same habitat as adults. But young snook must be careful. Big snook are cannibalistic. As such, small snook generally choose docks and other structures to hide. At this age, a snook’s diet consists of fish, shrimp, crabs and plant tissue.

Adult snook

Male snook may reach sexual maturity at one year, but typically by two to three years of age. Female maturity is around three to four years. The probability that common snook of a particular size will be female increases with length and age. On the west coast of Florida, at age five, there’s about a 50% mix of males to females. Although most male snook do transition to female, not all will. In Florida, the oldest female recorded was 15 years on the Gulf coast and 18 years on the Atlantic coast. The oldest male was 12 years on the Gulf coast and 15 years on Atlantic coast. Although the oldest snook recorded was 18 years, it’s thought they can live at least 20 years and probably closer to 30 years.


In southwest Florida, seventy percent of an adult snook’s diet consists of fish with pinfish (20%) and minnows (16%) rounding out the top two positions for prey items, followed by shrimp at 13%. Snook eat greater than ten times more pinfish in the summer months than in the winter even though more pinfish are available to them in the winter. This is likely because pinfish recruit to the estuary in the winter and are very small. Studies have shown that snook prefer prey 14% their own body length, so in the winter months, pinfish are much too small to be attractive to an adult snook. Snook feed on shrimp year-round but more so in the winter.

During winter months, snook stomachs contain only about a quarter of what is in them in the summer. This is likely because cold water causes their metabolic rate to slow, resulting in decreased feeding. In fact, snook are extremely cold sensitive and become lethargic and may die when water temperatures dip below 60 degrees for any length of time.

Snook management

Typically we have two closed seasons for snook, one corresponding to their spawning cycle, and the other to protect them during the winter when water temperatures drop. Anglers may continue to catch and release snook during closed seasons. Right now however, snook are catch-and-release only in all coastal counties from the Pasco/Hernando county line south through Gordon Pass in Collier County through Aug. 31, 2020 (UPDATE: extended through May 31, 2022 for Sarasota Bay through Gordon Pass), as a proactive measure due to impacts of red tide in this area.

19 Comments on “The life cycle of common snook

  1. Thanks for a great article. By the way, is your Florida fishing laws article of November 1, 2016, still good authority? Does the closed season on snook simply mean that it is catch and release or can one be cited for simply fishing for snook. I note that it is catch and release ion all coastal counties at all times currently.

    • Hi Steve. I’m glad you enjoyed the article. Yes, the November 2016 article is still correct. The closed season on snook means you can not possess one. You may still target them for catch and release. Thank you for that question! I will reword my blog to make that clearer. Betty

  2. Thank you for your excellent review of Snook. You mention that a major portion of snook diet is pinfish and minnows as the top tow prey items. I was under the impression that mullet fingerlings were a major prey fish due to their massive numbers in the Charlotte Harbor Estuary. If not, what is the role of mullet in our Estuary.

    • Hi Bill… Thank you for your comment. Finger mullet are prey for many different fish species including red fish, bluefish, tarpon, Spanish mackerel, jack crevalle, and snook… so they are vey ecologically important. And certainly if snook find finger mullet at the right size they are going to gorge themselves on them. Finger mullet however tend to have a particular habitat so they are not as big of a driver as pinfish are in the Charlotte Harbor estuary. For snook it’s all about prey size and there’s much more pinfish and minnow available to them in their preferred size range. This is not the same for all estuaries. In the Indian River estuary for instance, finger mullet are the primary driver. That is much more of a eutrophic system and doesn’t support the seagrass that we have here. Because we have much more seagrass habitat, we have much more pinfish and other bait species that depend on seagrass habitats. Hope this help. I am glad you enjoyed the post. Betty

  3. When a snook changes from male to female – do they change back to male?

    • Hi Dan… no, once transition from male to female occurs, it is permanent.

  4. Hello,

    Great article! What about he effects of water temps and the beginning of the spawn? 75 degrees? Also, is it safe to assume that they will only spawn on an incoming tide? TIA!

    • Hi Matt… Sorry for the delay. A paper by Ron Taylor says the annual reproductive cycle is confined to that period between the vernal (March) and autumnal (Sept) equinoxes when day length and water temperatures are maximal (he doesn’t give a specific water temp. and I haven’t seen one, but if I do I’ll post back here). Day length probably controls the duration of the annual reproductive cycle, and temperature serves as moderator as in other fishes. The beginning of the spawn correlates strongly with the maximum size of the eggs. As for tides, spawning episodes occur during the late afternoon and early evening hours during all lunar phases and all tidal stages. I’m glad you enjoyed the article!

      • Have never caught a mature snook during spawning season with eggs in tact. Could you comment on why this is occurring? Have caught well over 200 plus fish over the years during this time and have never encountered any eggs.

        • Hi Don… Snook season has been closed during peak spawning months (May through August) for many years. It would have been a long time ago when you could cut open a spawning snook during the peak months. So I suspect you are not seeing it because snook season is closed during most of the spawning season. Research scientists often find female snook loaded with eggs during the spawning seasons. Females will typically be a little larger than males and those fish caught closer to the Gulf passes will be more likely to have developed gonads.

        • Can you send a pic of a spawning snook? If fishing in freshwater and catching freshwater snook, is there a season on harvesting freshwater snook?

          • Hi Patrick… Thanks for your questions. I do not have a pic, but basically would look like streaks of milky water. Scientist confirm spawns by pulling a very fine mesh net and looking for eggs under the microscope. Regarding your second question, snook are considered a saltwater fish regardless of where they are fished, so saltwater rules apply including seasons, bag limits, size and saltwater fishing license with snook endorsement. See this blog on fishing license rules:

  5. Do snook return to the same river year after year after spawning example if I caught a 40in fish under a certain bridge what are the chances said fish would return to the same bridge after spawning?

    • Hi Anthony… Good question and it depends. Snook on the east coast of Florida tend to move around a lot whereas snook on the west coast tend to have a natal estuary. Some work in the Peace River showed that migrations to the river tends to be strongly associated with river levels and prey availability (see A couple studies in SWFL have looked at site fidelity in rivers. One in the Shark River (unpublished) suggests between 20-50% return to river (same spot which would be where a receiver was placed) presumably after spawning (data over 4 years). Another in the Caloosahatchee found that snook that do return to the river leave for approximately 3 months (June-August) presumably to spawn before returning. This study did not indicate the percentage that returned but did say the percentage that did not leave (skipped a spawning year) was about 40% (data over 3 years). Best regards… B

      • Wonderful article. So informative. May I ask for clarification of the localization of Red Tide? Pasco and Hernando had very little, if any tide detected, even in the most devastating season.

        • Hi Jillian… the closure is related to the prolonged 2017-2019 red tide. I don’t work on the regulatory side so can’t speak to why Pasco was included, but I understand the closure was in response to angler concern and fisheries data. That said, FWC is currently seeking angler input regarding the red tide closure of snook, redfish and spotted seatrout via virtual workshops to be held in early April (5, 6 & 8, with the 8th focused on the Tampa Bay area). Your question might be answered during the workshop. See link for details:

  6. Can snook reproduce in fresh water and still be fine? I’ve been told it can’t happen. Can anyone help me please.

    • Hi Justin… Snook need at least 28 parts/thousand salinity (80% strength of ocean salinity) in order to successfully spawn. Sperm gets activated at these salt levels and the eggs become buoyant. According to snook scientist Dave Blewett, snook that choose to skip spawning and spend their summer in a freshwater river on in the low salinity brackish waters of the bay will not even gear up at all physically for spawning. Both males and females remain dormant and don’t even try to spawn in these habitats. Most spawning along the Gulf coast, occurs near the passes in SWFL from May thru October, but locations can expand depending on the salinity levels within a given estuary during any given year.