Juvenile snook research in four Florida estuaries

juvenile snook
A juvenile snook is measured prior to releasing it back into the Manatee River. This fish is approximately one-year-old.

The common snook (Centropomus undecimalis) is arguably the most popular game fish in the state of Florida. With the popularity and reputation this fish has among anglers and scientists alike, it’s important to have the data needed to effectively manage this species on both of Florida’s coasts. Over the past three decades, our Fisheries-Independent Monitoring (FIM) program has collected data that has proven valuable and necessary to assess common snook populations in the state.

As FIM’s knowledge expanded on essential fish habitats for young-of-the-year and juvenile common snook, it became clear that the habitats into which these age classes recruited differed among estuaries. For example, habitats sampled as part of the FIM core program would produce hundreds of juvenile snook in Tampa Bay. Similar efforts along the same habitat types in Charlotte Harbor yielded little to no juvenile snook. Based upon these results, it was evident that more research was needed to better define the primary nursery areas for juvenile snook in Charlotte Harbor and other less productive estuaries. Furthermore, lack of size-at-age data on age-1 snook was recognized by the FWC when a snook stock assessment was released in 2013, warranting further research and more collections of this important age class of snook.

men in water pulling in net

With support from the Snook Stamp fund, the FIM program began sampling in new backwater habitats in 2014 and developed and initiated standardized sampling protocols to address this data gap for the four estuaries sampled by the FIM program in which common snook frequently occur. These estuaries included Tampa Bay, Charlotte Harbor, Northern Indian River Lagoon and Southern Indian River Lagoon. Short-term grants allowed the FIM program to better understand juvenile common snook habitats by extending sampling into smaller tidal tributaries and creeks where the standard FIM program rarely sampled as part of the core program.

During a one-year pilot study, FIM staff tested various types of seine nets in these four estuaries to collect data on juvenile snook and other species that were sampled. The data collected during this gear testing phase have been important in informing common snook stock assessments and setting a standard for the continued sampling of juvenile snook in Florida. Biologists continue to conduct routine snook sampling year-round on a monthly basis.

measuring snook
An FWC scientist measures a juvenile snook caught in the Manatee River.

Since more focus has been placed on Age 0-1 fish in recent years, researchers have discovered some interesting things about juvenile snook and the habitats they use. Age-0 common snook recruitment, or the number of fish surviving to enter the fishery, varies from year to year. Habitats to which Age-0 common snook recruit differ between estuaries, and very small tidal tributaries and creeks are vital habitats for young snook.

Continuing to monitor annual abundance and collect size-at-age data are the most important things that the FIM program can do to inform snook stock assessments in years to come. Any break in that sampling jeopardizes FWRI’s ability to adequately assess and manage this stock.

The FIM program will continue their sampling into smaller tidal creeks and estuaries to better understand the habitats for juvenile common snook and how these habitats differ between estuaries. Anglers, researchers and other stakeholders around the state are invested in this fishery for the long-term, and learning more about snook at each stage of life will ensure their habitats and future generations are well managed and protected for years to come.

 

Additional Information
2015 Common Snook Stock Assessment