If You Want Better Recruitment Estimates, Stratify Your Sampling by Habitat

By Jeff Schaeffer | AFS Co-Chief Science Editor. E-mail: [email protected]

Grey_snapper_-_Lutjanus_griseusManagement of many fish species requires good recruitment estimates; this is especially true for Gulf Coast reef fishes that are harvested intensively. One of the most important of these is Gray Snapper Lutjanus griseus, which are a primary target of nearshore fisheries in Florida. Gray Snapper have been assessed annually during routine surveys, but Kerry Flaherty-Walia and her colleagues at the Florida Fish and Wildlife Conservation Commission’s Fish and Wildlife Research Institute have discovered a new way to improve estimates by deploying a novel approach in a habitat that had been undersampled. They used a large (183 m) haul seine to sample deep polyhaline seagrass beds and found that they were hotspots for juvenile Gray Snapper; numbers there were greater than obtained from standard surveys, and larger juveniles were abundant. Their data improved confidence in recruitment estimates as well as provided a window into a life stage for which few data were available. But they did this by developing an open-water sampling approach using a gear that had generally been used on shorelines. This is an important article because it not only had a positive outcome for managers concerned with recruitment, but it demonstrates the value of stratified sampling across habitats and, most of all, the value of deeper seagrasses as habitat, not only for Gray Snapper, but other fishes as well. Their work also makes us think that haul seines would be useful sampling techniques in other habitat types.

REFERENCE

Flaherty-Walia, K. E., T. S. Switzer, B. L. Winner, A. J. Tyler-Jedlund, and S. F. Keenan. 2015. Improved ability to characterize recruitment of Gray Snapper in three Florida estuaries along the Gulf of Mexico through targeted sampling of polyhaline seagrass beds. Transactions of the American Fisheries Society 144:911-926. dx.doi.org/10.1080/00028487.2015.1054516

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