2 results

Otolithic age determination of mature southern bluefin tuna (Thunnus maccoyii)

Project number: 1985-076
Project Status:
Completed
Budget expenditure: $0.00
Principal Investigator: John Thorogood
Organisation: John Thorogood
Project start/end date: 27 Jun 1986 - 29 Jun 1986
Contact:
FRDC

Objectives

1. Collect otoliths from SBT &gt
130 cm. Determine time & periodicity of otolith band formation, hence seasonal & yearly growth rates. Validate otolith age determination methods developed from juvenile SBT for mature SBT. Age determination method independent of

Final report

Author: John Thorogood
Final Report • 2011-08-01 • 2.78 MB
1985-076-DLD.pdf

Summary

Otoliths of Southern Bluefin Tuna (Thunnus maccoyii) taken from waters off New South Wales, South Australia, and Western Australia, of between 42 cm and 167 cm F.L. were prepared to reveal annual banding.

Methods of preparation and examination are detailed.

Otolith growth was demonstrated to be directly proportional to fish growth for the size range studied.

Sampling over 13 months provided validation of the annual nature of bands for fish in their 3rd, 4th and 5th year of growth. Band formation of fish in their 2nd, 6th, 7th, 8th and 9th years of growth also appeared to be annular, though samples were available from an insufficient number of months for confident validation.

Von Bertalanffy growth parameters were derived from determined age-at-length data.

Study of the reproductive biology of the southern bluefin tuna (Thunnus maccoyii (Castlenau)) off the coast of Australia

Project number: 1984-056
Project Status:
Completed
Budget expenditure: $0.00
Principal Investigator: John Thorogood
Organisation: John Thorogood
Project start/end date: 28 Dec 1986 - 31 Dec 1986
Contact:
FRDC

Objectives

1. Determine the age at first maturity for SBT from Aust waters. Update, enlarge knowledge & expertise relating to examination of SBT gonads.
2. Further knowledge of pattern & process of development of gonads, strategy of spawning, & fecundity in relation to age/size
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