1. 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
Total lengths (TL) ranged from 145–1038 mm
Weights ranged from ,800.0 g
Most dominant size class: 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 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 , 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., 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.