Preliminary validation of age-at-length of red abalone, Haliotisrufescens, using bomb radiocarbon

摘要

Current methods to describe the age-at-length relationship of red abalone (Haliotis rufescens Swainson) are insufficient to determine the ages of large individuals because their shell lengths exceed those predicted by model L values. We evaluated the utility of analyzing atomic bomb generated radioisotope super(14)C in shell as a method to validate the age-at-length relationship of H. rufescens. Fabens' (1965) method was used to determine von Ber-talanffy growth function (VBGF) parameters (L 313 mm, k = 0.051 y super(-1) (0.042 to 0.059, 95% CI)) based on data from a multi-year, multi-site tag-recapture study. Shell carbonate was sampled at four locations on a single shell (251 mm, maximum shell length (MSL)) with the objective to bracket the rise of the radiocarbon signal, known to occur during similar to 1957 in the NE Pacific. There was close correspondence to the radiocarbon values of extracted shell carbonate and estimated dates of formation based on VBGF estimates. The 251 mm (MSL) red abalone specimen was predicted to be 27 to 38 years old. This study presents preliminary results from radiocarbon analysis of shell carbonate and demonstrates the utility of validating the age-at-length relationship of red abalone with this method.