Improved Ability to Characterize Recruitment of Gray Snapper in Three Florida Estuaries along the Gulf of Mexico through Targeted Sampling of Polyhaline Seagrass Beds

Abstract

Estuarine-dependent Gray Snapper Lutjanus griseus support extensive recreational fisheries in estuarine and coastal waters throughout the eastern Gulf of Mexico. Multiyear fisheries-independent monitoring data collected in three Florida estuaries can be used to estimate the strength of juvenile Gray Snapper recruitment, which has been critical to assessments of other fish populations. Earlier evaluation of these data indicated that Gray Snapper inhabit polyhaline seagrass beds, which are underrepresented in ongoing monitoring efforts. During this study, in addition to the routine monitoring of shorelines and channel habitats, sampling of shoal and deepwater polyhaline seagrass habitats was implemented using 183-m haul seines and 6.1-m otter trawls. The incorporation of polyhaline seagrass surveys from 2008 through 2011 allowed a more thorough sampling of the Gray Snapper population, resulting in improved catch rates, increased frequency of occurrence, and a substantial reduction of the coefficient of variation for CPUE in most years and estuarine systems. Habitat-based sampling of polyhaline seagrass habitats also provided additional data for annual abundance indices and therefore improved the ability to characterize the strength of recruitment for Gray Snapper over time. These results demonstrated that periodically reevaluating habitat-based stratification approaches to estimate fish abundance indices from long-term surveys can lead to more precise estimates and greater numbers of measured individuals, which are key components of successful monitoring programs.

Received October 24, 2014; accepted May 14, 2015

ACKNOWLEDGMENTS

First and foremost, we acknowledge the countless personnel and volunteers of the Florida Fish and Wildlife Conservation Commission who have assisted with the collection and processing of data since the inception of this survey. Special thanks go to K. Fischer and A. Knapp for coordinating and selecting sites for the seagrass-sampling portion of this field study and to G. McLaughlin and J. P. Davis for logistical support and leadership in the field portion of the Marine Fisheries Initiative (MARFIN) grant that helped support this research. We also thank N. Cummings and R. Sadler (National Oceanic and Atmospheric Administration [NOAA], National Marine Fisheries Service [NMFS], Southeast Regional Office) for scientific insight and grant administration, respectively, during this project. Thanks to K. Fischer, P. W. Stevens, D. Chagaris, C. B. Guenther, B. Crowder, and two anonymous reviewers for providing feedback and useful editorial comments that greatly improved the quality of this manuscript, and to R. H. McMichael Jr., for his support and assistance. This project was supported in part by proceeds from sales of state of Florida saltwater recreational fishing licenses, by funding from the U.S. Department of the Interior, U.S. Fish and Wildlife Service, Federal Aid for Sportfish Restoration Project Number FL-F-F14AF00328, and from the U.S. Department of Commerce, NOAA, NMFS, MARFIN grant (NA09NMF4330152). The statements, findings, views, conclusions, and recommendations contained in this document are those of the authors and do not necessarily reflect the views of the Department of the Interior or the Department of Commerce and should not be interpreted as representing the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government.