AFSC/ABL: NPRB project 1106 Improved aging estimates for spiny dogfish

The spiny dogfish (Squalus suckleyi, formerly Squalus acanthias, Ebert et al. 2010) is a small, long-lived and slow-growing shark, which is vulnerable to overfishing. Current methods for aging spiny dogfish are based on reading annuli from dorsal fin spines, which erode and may break. For the past 30 years, scientists have used an exponential relationship between the diameter of the spine and the number of annuli to estimate the number of missing annuli. Coupled with between-reader imprecision (CV = 19%), errors in estimation of worn annuli introduce uncertainty and bias into the aging process, resulting in large confidence intervals and imprecise growth, mortality, and recruitment estimates necessary for stock assessments. Using spines and vertebrae collected from spiny dogfish in the Gulf of Alaska, we aged the spines using conventional methods and vertebrae using the vertebral method. Data presented here includes the sample collection information, raw spine and vertebrae age read data and final annuli counts calculated from the multiple reads. This project was funded by NPRB and was a collaborative work between: AFSC age and growth lab, WA Dept Fish and Wildlife, NWFSC age and growth lab, Dr. Walter Bubley and UAF, and Bechtol Research