Matthew Donaldson , and J. Read Hendon Preliminary assessment of black drum (Pogonias cromis) age and growth from Mississippi coastal waters William D. Dempster, Christopher M. Butler, Jason D. Tilley, Michael V. Buchanan, Gary Gray, Matthew Donaldson , and J. Read Hendon Center for Fisheries Research and Development, Gulf Coast Research Laboratory, The University of Southern Mississippi, Ocean Springs, MS Background Black drum (Pogonias cromis; Figure 1) support important recreational and commercial fisheries in Mississippi coastal waters Currently, directed fisheries of black drum in Mississippi waters are not restricted by size or catch limitations Statewide, black drum life history is limited to data collected from the 1980’s-early 2000’s Current age and growth information is required for future management initiatives for the species Yearly opaque rings were deposited from Jan-Jun (Figure 6) Majority of rings were deposited in April Data corroborates current estimated birthdate (April 1) Figure 3. Black drum otolith annuli (A) and incremental margin codes (B). Margin codes defined as: 1. opaque zone present on edge; 2. translucent zone forming to 1/3 complete; 3. translucent zone 1/3 to 2/3 complete; and 4. translucent zone 2/3 to fully complete Courtesy: S. VanderKooy A) B) Figure 4. Length frequency distribution (A) and length-weight relationship (B) for black drum used in this study Preliminary results 1,328 black drum collected between 2008-2015 Total lengths (TL) ranged from 145–1038 mm Weights ranged from 39.5-18,800.0 g Most dominant size class: 251-300 mm (n=405)(Figure 4A) Total length was highly correlated with weight (Figure 4B) B) Figure 6. Proportional margin code deposition by month Summary Majority of sampled black drum were sexually immature Fish in the 251-300 mm size class represented 33.7% of total black drum catch Black drum ages ranged from 0-29 years Age 1-2 fish were the dominant age class Otolith ring deposition occurs annually in early spring and appears to match current literature Courtesy: J. Franks Figure 1. Image of black drum A) =Male =Female =Unknown Objectives Examine black drum length-weight relationship Provide current age and growth parameters Compare monthly otolith ring deposition with age assessment guides1 Future work Increase sample size of small (<150 mm) and large (>600 mm) size classes Examine sex-dependent growth rates Compare growth parameters to those in other regions Examine reproduction of black drum in Mississippi coastal waters Materials and Methods From 2008-2015, black drum were sampled using a scientific gillnet and handline Recorded weight (g) and length measurements (mm) Otoliths were removed (Figure 2A), molded in epoxy using histological trays, cross-sectioned on an IsoMet® saw (Figure 2B), and mounted on microscope slides (Figure 2C) Annual growth bands (Figure 3A) and incremental margins (Figure 3B) were counted using a microscope Oldest observed age was 29 years (Figure 5) Majority of fish collected were <5 years Figure 5. von Bertalanffy growth curve of black drum (combined sexes) from Mississippi coastal waters L∞=1037mm k=0.11 t0=-1.33 =Male =Female =Unknown References 1VanderKooy, S., 2009. A practical handbook for determining the age of Gulf of Mexico fishes, 2nd ed. Gulf States Marine Fisheries Commission, Ocean Springs, MS. pp.156. 2A 2B 2C Acknowledgements This research was funded by the U.S. Fish and Wildlife Service’s Sportfish Restoration Program through the Mississippi Department of Marine Resources. J. Franks and S. VanderKooy provided images.