Project number:
1995-039
Project Status:
Completed
Budget expenditure:
$23,174.00
Principal Investigator:
Ronald E. Thresher
Organisation:
CSIRO Oceans and Atmosphere Cleveland
Project start/end date:
16 Aug 1995
-
29 Oct 1996
Contact:
FRDC
1. To ensure continuity of monitoring gemfish recruitment in order to obtain better information on possible effects of environmental variability and overfishing on the stock
Final report
Author:
Ron Thresher and Derek Staples
Final Report
•
1996-03-06
•
1.68 MB
1995-039-DLD.pdf
Historically, monitoring of the eastern gemfish stock has been based on sampling at NSW fish markets, and carried out by NSW Fisheries Research Institute as part of its NSWs management responsibilities for the fishery. With the advent of AFMA, however, responsibility for monitoring of the fishery passed to the commonwealth, and its implementation has not been put on a firm footing. The need for continued monitoring of the fishery and the stock is particularly critical given the recent collapse of the fishery, at best qualitative indices of whether or not the condition of the stock is improving as a result of the closure, and continuing uncertainty about the future of the stock or the fishery. As a result of the uncertain plans by AFMA for monitoring the current gemfish by-catch, SETMAC recommended that a proposal be developed for submission to the FRDC to support an interim by-catch monitoring program for the 1995 spawning run, while longer term arrangements for monitoring the state of the stock could be developed.
Following a successful application, NSW FRI was contracted to continue its monitoring of the gemfish fishery and stock, as indicated by by-catch. The monitoring was completed as planned, based on on-board sampling, port sampling and market sampling. Data and samples collected include catch numbers, length frequencies and otoliths for age analysis.
The data indicate a continuing decline in the number of large, older fish in the stock. The by-catch is dominated by juveniles and small. adults from the 1990 and 1991 year-classes. The 1992 year-class continues to look weak, whereas 1993 appears to have produced a much stronger year-class. Interpretation of the relative sizes of the peaks in the length frequency data is difficult, however, due to uncertain effects of sampling biases.
These data have been provided to industry at meetings of the Eastern Gemfish By-catch Working Group, the Gemfish Stock Assessment Group and the Eastern Gemfish Workshop. The data were also provided to scientists doing the gemfish stock assessment and evaluating harvest strategies for Australian fisheries at the risk of economic collapse.
