Andres Navarro Martinez
The population status of most elasmobranchs has shown a decline in recent decades because certain life-history traits make them vulnerable to threats such as overexploitation. The juvenile stages of elasmobranchs are the most vulnerable; for this reason, the study of nursery areas is important.
It has been proposed that a nursery area must meet three criteria: 1) there is a higher abundance of neonates, and young-of-the-year juveniles compared to adjacent areas, 2) individuals tend to remain in the nursery area, and 3) the nursery area is used repeatedly over the years.
Some studies suggest that Ascensión Bay may serve as a nursery area for elasmobranchs. However, despite being a protected area, Ascensión Bay lacks studies regarding its potential role as a nursery area for elasmobranchs.
This study aims to determine whether Ascensión Bay functions as a nursery area. An independent fishery survey will be carried out using bottom longlines consisting of 300 m of braided silk mainline, with 50 branch lines of 1 m each, fitted with 12/0 circle hooks. The longlines will be deployed at various points in the bay for one hour, in cooperation with local fishers, during five trips at different times of the year. Sampling points will be selected using a stratified random design.
The analyses to be performed for each species are: comparing the abundances of neonates and young-of-the-year juveniles within the bay and in adjacent areas, comparing size distributions and mean sizes to infer whether growth occurs within the bay, and finally, detecting at least two birth pulses.