Nursery grounds and maturation of the sandbar shark in the western North Atlantic

• Main Author: Merson, Rebeka Rand
• Format: Text
• Language: English
• Published: DigitalCommons@URI 1998
• Subjects: Oceanography|Zoology; South Bay; North Atlantic
• Online Access: https://digitalcommons.uri.edu/dissertations/AAI9921548

Surveys were conducted in selected coastal bays from Delaware to New York to describe sandbar shark (Carcharhinus plumbeus) essential habitat, assess abundance, growth during the nursery season, and length-at-birth in Delaware Bay, and to delimit the current northern limit of pupping grounds along the US east coast. Additionally, reproductive tracts from sandbar sharks were sampled to describe development, length-at-maturity, litter size and gonadal cycle. Neonate and juveniles (n = 943) ranging from 40 to 120 cm fork length (FL) were captured in Delaware Bay from June to October between 1995 and 1997. Results from gillnet and longline sampling and tag-recaptures show the main pupping area is located along the southwest coast of Delaware Bay. Mean length-at-birth is 50 cm FL in Delaware Bay. No sandbar sharks were caught in the historical pupping grounds of Great South Bay, New York. Seventeen sandbar shark neonates ranging in length from 42 to 52 cm FL were captured by gillnet in Great Bay, New Jersey. Results support that Great Bay, New Jersey is the current northern boundary of sandbar shark pupping grounds along the US east coast. In males and females, marked increases in reproductive tract anatomy occurs at about 140 cm fork length (FL), indicating the transition between juvenile and subadult stages. The smallest mature female was 148 cm FL and the largest immature was 175 cm FL. The smallest mature male was 139 cm FL and the largest immature was 153 cm FL. Probit analysis was used to produce comprehensive maturity schedules for males and females. Length-at-maturity in both female and male sandbar sharks are consistent with reports in the literature, but the maturity schedules produced here describe the range in length-at-maturity.