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
Research Fronts
Sample Issue
For Authors
General Information
Instructions to Authors
Submit Article
Open Access
For Referees
General Information
Review Article
Referee Guidelines
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 58(9)

Variable growth band deposition leads to age and growth uncertainty in the western wobbegong shark, Orectolobus hutchinsi

Justin A. Chidlow A D, Colin A. Simpfendorfer B, Garry R. Russ C

A Western Australian Fisheries and Marine Research Laboratories, PO Box 20, North Beach, WA 6920, Australia.
B School of Earth and Environmental Sciences, James Cook University, Townsville, Qld 4811, Australia.
C School of Marine Biology and Aquaculture, James Cook University, Townsville, Qld 4811, Australia.
D Corresponding author. Email: justin.chidlow@fish.wa.gov.au
 
PDF (694 KB) $25
 Export Citation
 Print
  


Abstract

Age and growth parameters of Orectolobus hutchinsi were estimated using micro-radiographs of sectioned vertebrae from 182 wild caught individuals. Two fluorochrome marker dyes, calcein and oxytetracycline, were used to validate the timing and periodicity of vertebral band formation in nine individuals held in the laboratory for between 423 and 472 days. Growth bands were difficult to interpret and final counts were obtained from only 98 (53.8%) individuals ranging in total length (TL) from 63 to 146 cm. The timing of growth band formation in the vertebrae of captive animals had no predictable temporal pattern, with formation occurring during all seasons of the year, making age validation difficult. Growth band formation was hypothesised to be influenced by non-periodic changes in centrum or somatic growth rather than seasonal growth, as observed in many other elasmobranch species. Growth rates of nine O. hutchinsi held in captivity varied considerably, ranging from 3.5 cm year–1 to 13.8 cm year–1 in total length (mean = 7.03 cm year–1). Although the periodicity of vertebral band formation in captive animals did not support a synchronous annual pattern, captive growth rates matched those predicted when an annual band pattern was assumed for wild caught individuals. Von Bertalanffy growth parameters estimated from vertebral analysis assuming an annual banding pattern and a mean size of birth of 24.1 cm were: L = 149.45 cm and K = 0.117 year–1 for both sexes combined. These results illustrate the fundamental importance of validating the periodicity of growth band formation in elasmobranch age and growth studies as it has considerable implications for the management of fisheries that exploit shark and ray species that may exhibit asynchronous growth band deposition.

Keywords: fluorochrome marker dyes, micro-radiograph, vertebral ageing.


   
Subscriber Login
Username:
Password:  

    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2014