| 05 January 2010
FWC solicits assistance from anglers to characterize the recreational fishery for gray (mangrove) snapper (Lutjanus griseus) and estimate discard mortality rates in the greater Tampa Bay region
The Florida Fish and Wildlife Conservation Commission’s (FWC) Fish and Wildlife Research Institute (FWRI) recently received federal funding (a Cooperative Research Program grant) to characterize recreational catch, effort, and discard mortality rates of gray snapper captured within Tampa Bay and nearshore Florida waters (Figure 1). We are soliciting help from recreational fisherman and Tampa Bay Florida Fishing Guides to help with this important research.
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Background
Gray (mangrove) snapper, Lutjanus griseus, reside within Florida’s estuaries during their first several years and are most often found in coastal and offshore waters near structure as adults. Juvenile gray snapper, like several other reef fishes, occupy estuarine nursery areas such as seagrass beds or mangrove shorelines during their early life history. Gray snapper tend to remain in mangrove habitats longer than other reef-associated fishes, and some mature individuals have been found in higher abundance in mangrove habitats than nearby coral reefs. Adult gray snapper are most often found in deeper channels or near structured hard-bottom habitats within the bay or near hard bottom and high relief areas in Gulf nearshore waters.
The FWRI Fisheries-Independent Monitoring (FIM) program is designed to monitor trends in the distribution and abundance of fish populations in Florida’s estuaries. Due to the logistics of traditional nets used in this scientifically-designed monitoring program, structured habitats within the estuary (e.g., bridges, limestone rock outcroppings, natural and artificial reefs) are undersampled, thus little is known regarding the relative importance of these habitats to estuarine-dependent reef species. Fisheries-independent sampling using hook-and-line gear does not have the same constraints as traditional nets and can provide information on reef fishes associated with structured habitats in addition to detailed disposition data on each fish. Targeting deeper water structure within the bay and nearshore gulf will likely collect large sub-adult and adult gray snapper and will provide an expanded understanding of size-specific habitat use. By conducting hook-and-line sampling using similar gear and methods employed by the recreational fishery, additional data will be collected on the composition of recreational catch, bycatch, and associated discards.
The bulk of gray snapper landings in the Gulf of Mexico occur in Florida, especially in the South. In addition to angling pressure on adult gray snapper, recreational fishers targeting other popular inshore fish (i.e., red drum, snook, etc.) may incidentally catch sub-legal gray snapper and other reef fishes within estuarine waters. Due to the extensive fishing pressure on gray snapper and other reef species, minimum size and bag limits have been employed to prevent overexploitation. It is likely that a substantial proportion of many reef fish species caught within estuarine waters are subsequently released due to minimum size limits. The effectiveness of minimum size limits depends heavily on the survival of released individuals; accordingly, it is critical to estimate the rate of discard mortality.
Fishing related mortality of undersized gray snapper may add to rates of natural mortality at sizes susceptible to fishing pressure. Discard mortality rates of undersized individuals may reduce subsequent recruitment into the fishery, while for legal individuals, discard mortality of individuals beyond established bag limits may influence population-level reproductive capabilities. Data on discard mortality have become even more important in recent years as fishing effort and subsequently the number of individuals released has increased. Discard mortality rates for various reef fishes have previously been estimated from tag return data, models, and cage experiments; however, specific discard mortality studies targeting gray snapper have not yet been conducted. Such estimates of discard mortality rates for gray snapper will be invaluable when fully assessing the effects of fishing on estuarine and nearshore populations.
The objectives of this research are to:
- Characterize recreational discard mortality rates of gray snapper captured within Tampa Bay and nearshore Florida waters.
- Develop sampling methods to more effectively collect detailed recreational catch, effort, and disposition data for gray snapper and other estuarine-dependent reef fishes associated with inshore and nearshore gulf habitats.
This Cooperative Research Project (CRP) aims to build collaborative partnerships between scientists and stakeholders to increase the exchange of information and improve the quality of data provided by research and monitoring programs. Working with recreational fishing guides and volunteer anglers will incorporate the variability in fishing expertise needed to accurately calculate fishery-applicable discard mortality estimates and will educate and involve the appropriate user groups in this type of research.
How can you help?
Report tag recaptures
If you catch a tagged gray snapper, please record the tag number, date and time of capture, where the fish was caught, fish length, and whether the fish was kept or released. If you release the fish, please do not remove the tag so that we may continue to gather data from that tagged fish. Please call the Fish Tag Hotline at 1-800-367-4461 or email This e-mail address is being protected from spambots. You need JavaScript enabled to view it with this information and you will receive a t-shirt!
Download/View Angler Questionnaire/SurveyFill out a questionnaire
To accurately characterize hook and line sampling effort and to gauge interest in participation in this project, we have put together a survey available above. Please fill the survey out, and we will contact you with additional details. On the survey you can designate if you are willing to:
Volunteer to hook and line fish on FWC vessels
We are looking for recreational fishing guides and anglers to volunteer on monthly hook and line trips conducted on weekdays by FWC scientists.
Allow an FWC observer on your vessel
If you are fishing for gray snapper within Tampa Bay or its nearshore waters, we would like to come with you to record data on the fish you are catching and methods you are using.
Participate in angling for mortality experiments
We will be conducting mortality experiments to determine short-term mortality rates of gray snapper that are caught and released. Volunteers participating in these studies will angle for fish and assist with the collection of valuable data.
For more information on this exciting project, please contact Mandy Tyler-Jedlund or Kerry Flaherty at (727) 896-8626, or email us at
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Figure 1. Map of inshore and nearshore Tampa Bay study regions.
