5 research outputs found
Sex-Specific Growth and Reproductive Dynamics of Red Drum in the Northern Gulf of Mexico
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 sexâspecific 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 threeâparameter von Bertalanffy growth function (VBGF) was the best candidate lengthâatâage model. No significant difference in growth between sexes was observed with the threeâparameter VBGF, despite the femaleâspecific curve having a larger mean asymptotic length than the maleâspecific curve. All seven candidate growth models predicted similar mean lengthâatâage estimates, and four of them exhibited significant differences in sexâspecific mean length at age, with females reaching a larger length at age than males after age 5. There was no significant difference between the sexâspecific weightâatâlength 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 5â6. 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