African Journal of Marine Science

Log in or Register to get access to full text downloads.

Remember me or Register

DOWNLOAD FULL TEXT Open Access  DOWNLOAD FULL TEXT Subscription or Fee Access

Do dart tags suppress growth of dusky kob Argyrosomus japonicus?

MH Griffiths, CG Attwood


Growth rates of dusky kob Argyrosomus japonicus calculated from mark-recapture and otolith-reading methods were compared. Mark-recapture data showed that A. japonicus are resident in an area between the Breede River Estuary and Cape Agulhas on the southeast coast of South Africa. Maximum recapture length was 1 150mm. A von Bertalanffy growth curve, fitted to length-at-age data derived from otolith sections of 168 specimens (1–42 years) from the Breede Estuary and adjacent marine environment, was differentiated to provide instantaneous length-based growth rates. Comparison of mark-recapture and otolith-based growth rates revealed that external dart tags suppress growth of A. japonicus <750mm, but do not affect the growth of larger fish.

Keywords: growth rate; mark-recapture; movement; otolith sections

African Journal of Marine Science 2005, 27(2): 505–508
AJOL African Journals Online