Bottom Longline Survey in the Northeastern Gulf of Mexico: The Effectiveness of Cooperative Research Projects

As technology advances (e.g. fish finders and plotters) and increases in fishing effort on the west Florida shelf have occurred, inshore fisheries are becoming maximally exploited and fishers are being displaced into deeper water.  Given the lack of knowledge in the biology and ecology of deepwater fisheries, there is a concern of how these stocks will be affected by increased fishing pressure.  Stock assessments in the Gulf of Mexico have historically relied on biological sampling collected through the interception of commercial catches; however, deepwater species are gutted at-sea and limits the retrieval of reproductive tissue. The NOAA Fisheries Service Cooperative Research Program (CRP) involves commercial and recreational fishers in the collection of fundamental fisheries information, and thus provides a means to gather samples, and detailed habitat and spatial data unattainable at the docks.  We received funding from this program to better inform future stock assessments for deepwater tilefishes. This CRP consisted of a bottom longline survey conducted in the northeastern Gulf of Mexico monthly using a randomized sampling program stratified by depth (100-399 m), two bait types, with 200 #13/0 circle hooks evenly spaced along a three mile mainline.  A total of 51 longline sets were completed with 10,188 hooks deployed.  The catch consisted of a total of eight species of elasmobranches (296 sharks) and twelve species of teleosts (654 teleosts) with gulf hake (Urophycis cirrata) and golden tilefish (Lopholatilus chamaeleonticeps) as the dominant teleosts captured (CPUE 0.03/hook hr).  There were no differences between catch per unit effort (hook/hour) and bait type (scad or squid) regardless of the bait status (no bait, bait remained on the hook, or fish caught).  Positive catches of golden tilefish (n = 294) were associated with Cuban dogfish (Squalus cubensis) and gulf hake.  This project collected similar sized and aged golden tilefish compared to fish caught in the commercial fishery (length: CRP, 301 – 966 mm; CM, 274 – 1145 mm; age: CRP, 3 – 28 yr; CM, 3 – 25 yr).  Female golden tilefish were determined to spawn January – June, with peak spawning in April.  At a minimal cost ($115,000) this project provided vital information regarding the age, length, reproductive seasonality, temporal changes in catches by sex, and site specific capture information.  Cooperative Research Projects provide an essential link among biologists, analysts and fishers.