CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Marine & Freshwater Research   
Marine & Freshwater Research
Journal Banner
  Advances in the Aquatic Sciences
 
blank image Search
 
blank image blank image
blank image
 
  Advanced Search
   

Journal Home
About the Journal
Editorial Board
Contacts
Content
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Sample Issue
For Authors
General Information
Instructions to Authors
Submit Article
Open Access
For Referees
General Information
Review Article
Referee Guidelines
Early Career Referee Mentoring
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with us
blank image
facebook twitter youtube

 

Article << Previous     |     Next >>   Contents Vol 51(7)

Ageing, catch-at-age and relative year-class strength for snapper (Pagrus auratus) in northern Spencer Gulf, South Australia

David McGlennon, G. Keith Jones, Janine Baker, W. Bruce Jackson and Martine A. Kinloch

Marine and Freshwater Research 51(7) 669 - 677
Published: 2000

Abstract

Commercial landings of Pagrus auratus declined to 25-year lows in South Australia in 1994, and sustainability of the fishery was questioned. This study investigated two potential explanations for the decline – changes in fishing effort and recruitment variability. Data for 1983–97 from northern Spencer Gulf, which contributes the majority of snapper catches in the State, showed that 74% of the variance in targeted catch was explained by catch per unit effort, and 20% by fishing effort. Recruitment variability was examined by analysis of age structures of the commercial catch. An ageing procedure was established by examining sectioned sagittal otoliths of 1046 snapper caught in 1991 and 1994/5; their use was first evaluated by assessing the bias and precision of multiple readings and by comparing annulus counts with ring counts from scales. The timing of annulus formation was determined by marginal increment analysis. Interpretation of the age structures suggests that year-class strength is highly variable and has a strong influence on catch patterns in the commercial fishery. A qualitative comparison of temperature with year-class strength did not show a strong relationship.

Keywords: otoliths, recruitment, catch and effort



Full text doi:10.1071/MF98095

© CSIRO 2000

blank image >
 
PDF (311 KB) $25
 Export Citation
 Print
  
  
Subscriber Login
Username:
Password:  

    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2014