Life-History Characteristics and Fishery Dynamics of Red Drum (<i>Sciaenops ocellatus</i>), in the North-Central Gulf of Mexico

<p>Red Drum (<em>Sciaenops ocellatus</em>) are highly targeted recreationally in the Gulf of Mexico, and support a small commercial fishery in Mississippi. Despite their popularity, the stock is assessed using data limited approaches that necessitate accurate life history information. I estimated the year-specific and year-aggregated escapement rates for the Mississippi stock (years 2004 to 2015), which were sensitive to mortality estimation methods; year-aggregated estimates were 6.9 to 28.2 % depending on the method, but temporal patterns were consistent. I then addressed concerns with previously estimated life-history characteristics by describing the sex-specific growth and reproductive dynamics. The three-parameter von Bertalanffy growth function was the best candidate length-at-age model, with no significant difference in overall growth between sex-specific relationships, but females had a larger mean asymptotic length, and four candidate models showed significant sexual dimorphism. I described Red Drum as batch spawners, with 3.7 days between successive spawns during the spawning season (August and September). The age at 50% maturity was around age-3 y in both sexes, but spawning capability was not evident until around age-6 y. The carbon (delta C-13) and nitrogen (delta N-15) stable isotope composition of Red Drum muscle tissue was more enriched in carbon offshore and was significantly different with respect to reproductive phase. Mean and variance of delta N-15 and variance of delta C-13 was significantly different between fish < age-7 y and those older. When accounting for muscle turnover rates, this coincides with the age of spawning capability, indicating an ontogenetic migration at age-6 y.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Discipline thesis:degree_discipline

Coastal Sciences, Gulf Coast Research Laboratory

Year dc:date.available

2018

Author dc:creator

• Bennetts, Corbin

Contributors dc:contributor

• Robert T. Leaf
• Nancy J. Brown-Peterson
• Kevin S. Dillon

• age and growth
• reproduction
• stable isotope analysis
• escapement rate
• Marine Biology
• Population Biology
• Statistical Models

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/348

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1391