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 Structure
Contacts
Content
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Virtual Issues
Sample Issue
For Authors
General Information
Scope
Submit Article
Author Instructions
Open Access
For Referees
General Information
Review an 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 LinkedIn

 

Article << Previous     |     Next >>   Contents Vol 57(2)

Age, growth, maturity, longevity and natural mortality of the shortfin mako shark (Isurus oxyrinchus) in New Zealand waters

S. D. H. Bishop A D, M. P. Francis B, C. Duffy C, J. C. Montgomery A

A School of Biological Sciences and Institute of Aquatic and Atmospheric Sciences, Private Bag 92019, The University of Auckland, Auckland, New Zealand.
B National Institute of Water and Atmospheric Research Ltd, Private Bag 14-901, Kilbirnie, Wellington, New Zealand.
C Department of Conservation, Private Bag 68908, Newton, Auckland, New Zealand.
D Corresponding author. Email: s.bishop@auckland.ac.nz
 
PDF (637 KB) $25
 Export Citation
 Print
  


Abstract

Shortfin mako sharks were aged by counting growth bands in sectioned vertebrae (n = 256), and assuming annual band-pair deposition. No systematic ageing bias was present and count precision was high. 0+ juveniles were identified from length–frequency plots and assigned ages based on a theoretical birth date of 1 October and their date of capture. A Schnute generalised growth model fitted to the combined vertebral and 0+ data described the growth patterns best. Shortfin makos grow very rapidly initially, increasing by ~39 cm fork length in their first year. Thereafter, males and females grow at similar but slower rates until about age 7 years, after which the relative growth of males declines. Longevity estimates were 29 and 28 years for males and females respectively. Natural mortality (M) is probably in the range of 0.10–0.15. Median ages at maturity were 7–9 years for males and 19–21 years for females. Comparisons of growth curves reported here and elsewhere suggest no regional differences in growth rates. The shortfin mako is a late-maturing species with moderate longevity and low natural mortality. With these life history characteristics and an unknown stock size and structure worldwide, management should be of a precautionary nature.

Keywords: ageing, conservation, fisheries management, vertebrae.


   
Subscriber Login
Username:
Password:  

    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2015