Age, Growth, Reproduction, and Diet of the Finetooth Shark, \u3ci\u3eCarcharhinus isodon\u3c/i\u3e, in the Northern Gulf of Mexico

The current study examined life history parameters of the finetooth shark, Carcharhinus isodon, in the northern Gulf of Mexico (nGOM) to provide an accurate description of the species’ reproductive biology, age, growth and diet composition. A total of 1,489 finetooth sharks (830 female; 659 male) were collected from coastal waters of the nGOM between Apalachicola Bay, Florida (29.873° N and 84.514° W) and East Bay, Louisiana (28.959° N and 89.279° W) from June 2006 through October 2013. Peak reproductive development occurred during May/June for both males and females, which was followed by mating and an 11-12 month gestation period. It was noted that mature females exhibited both annual and biennial reproductive periodicity, and it appears that the amount of energy reserves present could be driving this. The maximum observed age was 9.4 and 6.5 years and the age at 50% maturity was 4.1 and 3.6 years for females and males, respectively. The von Bertalanffy growth model estimates for females and males were L∞ = 1308-mm FL and k = 0.26/yr and L∞ = 1164-mm FL and k = 0.32/yr, respectively. Diet analysis was conducted on 518 sharks and revealed that teleosts dominated the diet, with Gulf menhaden, Brevoortia patronus, being the most important prey species. The results of this comprehensive study better defines finetooth shark life history in the nGO