Gonzalez, J.A1, Wiederwohl, C.2, Guneralp, I.3 and Steichen, J.L1
1Dept of Marine Biology, Texas A&M University, Galveston, TX; 2Dept of Oceanography, 3Dept of Geography, Texas A&M University, College Station, TX
Abstract:
Adult Atlantic blacktip sharks (Carcharhinus limbatus) rely on Texas bay ecosystems, yet increasing recreational fishing pressure may be influencing their distribution and ecological dynamics. This study examines how recreational fishing effort relates to adult blacktip shark abundance and prey availability across Galveston, Matagorda, and San Antonio Bays. Long‑term Texas Parks and Wildlife Department (TPWD) gill‑net surveys (1984–2023) were used to quantify adult shark abundances (>1400 mm), while bay trawl datasets provided measures of five key prey species: Red drum, Spotted seatrout, Atlantic croaker, Sand trout, and Gulf menhaden. Environmental variables, including salinity and temperature, were recorded during gill‑net deployments, and TPWD creel surveys supplied recreational angler‑hour estimates for high‑use months (May–November). Results indicate substantial variation among bays, with Matagorda Bay exhibiting the highest blacktip shark abundances, while Galveston and San Antonio Bays showed greater prey availability. Sharks occur more frequently in moderate to high salinity waters and at temperatures above 20°C. Preliminary patterns suggest a converse relationship between recreational fishing effort and blacktip shark abundance, highlighting potential indirect anthropogenic effects on coastal food webs. Understanding these dynamics is essential for effective coastal management as environmental change and human activity continue to reshape Gulf ecosystems.
