Sex-Specific Growth and Reproductive Dynamics of Red Drum in the Northern Gulf of Mexico

• Main Authors: Bennetts, Corbin F., Leaf, Robert T., Brown-Peterson, Nancy J.
• Format: Text
• Language: unknown
• Published: The Aquila Digital Community 2019
• Subjects: Life Sciences; Marine Biology; Red drum; Sciaenops ocellatus
• Online Access: https://aquila.usm.edu/fac_pubs/16239; https://aquila.usm.edu/context/fac_pubs/article/17550/viewcontent/sex_specific_growth_and_reproductive_dynamics.pdf; https://aquila.usm.edu/context/fac_pubs/article/17550/filename/0/type/additional/viewcontent/mcf210071_sup_0001_tables1_s2.docx

The Red Drum Sciaenops ocellatus stock is heavily targeted in the Gulf of Mexico (GOM) by recreational fishers and supports a small commercial fishery in Mississippi. Despite their popularity, little recent work has been done to describe their life history. In this work, we describe sex‐specific growth and reproductive dynamics of Red Drum collected from the northern GOM from September 2016 through October 2017. We evaluated seven candidate growth models and found that the three‐parameter von Bertalanffy growth function (VBGF) was the best candidate length‐at‐age model. No significant difference in growth between sexes was observed with the three‐parameter VBGF, despite the female‐specific curve having a larger mean asymptotic length than the male‐specific curve. All seven candidate growth models predicted similar mean length‐at‐age estimates, and four of them exhibited significant differences in sex‐specific mean length at age, with females reaching a larger length at age than males after age 5. There was no significant difference between the sex‐specific weight‐at‐length relationships. Red Drum are batch spawners that spawn in northern GOM coastal waters during August and September. We estimated 3.7 d between spawns and 10.5 spawning events per female in 2017. Nearly 20% of fish collected during the spawning season were sexually mature but reproductively inactive, indicating the possibility of skipped spawning. The age at 50% maturity was around 3 years (length at 50% maturity = 670 mm TL) in both sexes, but fish were not spawning capable until age 4.5 (703 mm TL) in males and age 5.8 (840 mm TL) in females. Furthermore, elevated gonadosomatic indices were not observed until around age 5–6. The updated life history information presented in this work helps to address current data limitations and provides critical information for future assessments of Red Drum stocks in the northern GOM.