Translator Disclaimer
1 April 2007 Overlap in utilization of juvenile Cape horse mackerel by Cape fur seals and the purse-seine fishery in Namibia
Author Affiliations +
Abstract
The Cape horse mackerel Trachurus trachurus capensis is one of Namibia's most valuable fish stocks, and an important component to the diet of Cape fur seals, Arctocephalus pusillus pusillus, off northern Namibia. The level of overlap in the utilization of this resource between seals and the purse-seine fishery was investigated using two overlap indices. For high overlap measures, seals and the purse-seine fishery utilized age-2 horse mackerel. For low overlap measures, seals mainly consumed age-0 fish whereas the fishery caught age-2 fish. Both indices were adjusted by the proportion of horse mackerel in the seal diet, with the assumption that the proportion consumed by the seals reflects the abundance of horse mackerel in the coastal waters of Cape Cross, Namibia. Both unadjusted and adjusted overlap indices showed that overlap between seals and the fishery in their utilization of juvenile horse mackerel was high only at times when horse mackerel abundance was high, and low when abundance was small. Confidence intervals and significance testing were included. Overall, there was little overlap between seals and the purse-seine fishery. This study provides important information that should be taken into account in the management of the horse mackerel resource.
Silvia Mecenero, Les G. Underhill, Jens-Otto Krakstad, Stephen P. Kirkman and Jean-Paul Roux "Overlap in utilization of juvenile Cape horse mackerel by Cape fur seals and the purse-seine fishery in Namibia," South African Journal of Wildlife Research 37(1), (1 April 2007). https://doi.org/10.3957/0379-4369-37.1.17
Received: 31 July 2006; Accepted: 1 November 2006; Published: 1 April 2007
JOURNAL ARTICLE
13 PAGES


SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top