Was Everything Bigger in Texas? Characterization and Trends of a Land-Based Recreational Shark Fishery

• Published in: Marine and coastal fisheries 2016-01, Vol.8 (1), p.553-566
• Main Authors: Ajemian, Matthew J, Jose, Philip D, Froeschke, John T, Wildhaber, Mark L, Stunz, Gregory W
• Format: Article
• Language: English
• Subjects: Carcharhinus leucas; Carcharhinus limbatus; Carcharhinus melanopterus; Catch composition; Exploitation; Fishery data; Fishing; Landing statistics; Marine fishes; National parks; Negaprion brevirostris; Population decline; Records; Recreation; Seasonal variations; Seasonality; Shark fisheries; Sharks; Species composition; Sport fishing; Stock assessment
• ISSN: 1942-5120; 1942-5120
• DOI: 10.1080/19425120.2016.1227404

Although current assessments of shark population trends involve both fishery-independent and fishery-dependent data, the latter are generally limited to commercial landings that may neglect nearshore coastal habitats. Texas has supported the longest organized land-based recreational shark fishery in the United States, yet no studies have used this “non-traditional” data source to characterize the catch composition or trends in this multidecadal fishery. We analyzed catch records from two distinct periods straddling heavy commercial exploitation of sharks in the Gulf of Mexico (historical period = 1973–1986; modern period = 2008–2015) to highlight and make available the current status and historical trends in Texas' land-based shark fishery. Catch records describing large coastal species (>1,800 mm stretched total length [STL])were examined usingmultivariate techniques to assess catch seasonality and potential temporal shifts in species composition. These fishery-dependent data revealed consistent seasonality that was independent of the data set examined, although distinct shark assemblages were evident between the two periods. Similarity percentage analysis suggested decreased contributions of Lemon Shark Negaprion brevirostris over time and a general shift toward the dominance of Bull Shark Carcharhinus leucas and Blacktip Shark C. limbatus. Comparisons of mean STL for species captured in historical and modern periods further identified significant decreases for both Bull Sharks and Lemon Sharks. Size structure analysis showed a distinct paucity of landed individuals over 2,000 mm STL in recent years. Although inherent biases in reporting and potential gear-related inconsistencies undoubtedly influenced this fishery-dependent data set, the patterns in our findings documented potential declines in the size and occurrence of select large coastal shark species off Texas, consistent with declines reported in the Gulf ofMexico. Future management efforts should consider the use of non-traditional fishery-dependent data sources, such as land-based records, as data streams in stock assessments.