Length-At-Age in Juvenile Patagonian Toothfish (Dissostichus eleginoides)

• Main Authors: Ashford, J., Jones, C., Bobko, S., Everson, I.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: ODU Digital Commons 2002
• Subjects: Age validation; CCAMLR; Length-frequency modal analysis; Population age structure; South Georgia; Southern Ocean; Antarctic region; Antarctica; Notothenioid fish; Aquaculture and Fisheries; Biology; Oceanography; Antarctic; Antarc*; Patagonian Toothfish
• Online Access: https://digitalcommons.odu.edu/oeas_fac_pubs/345; https://digitalcommons.odu.edu/context/oeas_fac_pubs/article/1354/viewcontent/Ashford2002LengthatAgeinJuvenilePatagonianOCR.pdf

We used the otoliths from a sample of Dissostichus eleginoides pre-recruits, whose length density was distinctly polymodal, to see whether ages estimated by reading otoliths were congruent with the length modes observed. Length densities by age were compared graphically with the overall length density observed. Additionally, ages were predicted for each fish based on length, and compared with ages estimated from reading otoliths in a goodness-of-fit test. The majority of the otoliths (83.6%) were estimated to be from fish 1+ or 2+ years old, with mean total lengths of 32.5 cm and 41.3 cm respectively. No difference was found between predicted and estimated ages. We conclude that the two dominant modes observed in the length density represent different age cohorts separated by one year.