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

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 densi...

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Bibliographic Details
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
Description
Summary: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.

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