Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
RESEARCH ARTICLE

Occurrence of juvenile bull sharks (Carcharhinus leucas) in the Navua River in Fiji

Diego Cardeñosa A , Kerstin B. J. Glaus B and Juerg M. Brunnschweiler C D

A School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY 11794, USA.

B School of Marine Studies, Faculty of Science, Technology & Environment, The University of the South Pacific, Private Mail Bag, Laucala Campus, Suva, Fiji.

C Independent researcher, Zurich, Switzerland.

D Corresponding author. Email: juerg@gluecklich.net

Marine and Freshwater Research - http://dx.doi.org/10.1071/MF16005
Submitted: 7 January 2016  Accepted: 9 March 2016   Published online: 24 May 2016

Abstract

Effective species conservation requires the protection of all stages of its life-cycle. The Shark Reef Marine Reserve (SRMR) in Fiji is a marine protected area where large numbers of adult bull sharks (Carcharhinus leucas) congregate due to food provisioning. At the end of a calendar year bull sharks leave the area for reproductive activity, but parturition sites are still unknown. Between February 2014 and January 2015, we interviewed local fishermen and conducted a fishing survey, so as to assess presence and abundance of bull sharks in the Navua River near the SRMR. In total 84% of fishermen reported either seeing or catching sharks up to 8 km upriver from the river mouth. They described them as small sharks having a rounded snout and being grey–brown in colour with a white belly, morphological characteristics that match juvenile bull sharks. During the fishing survey, a total of nine juvenile bull sharks were captured, including two that were recaptured after 108 and 92 days at liberty. Our findings confirmed the presence of bull sharks in the Navua River and provide a preliminary characterisation of a potential shark parturition or nursery area from a data-poor region.

Additional keywords: local ecological knowledge, nursery area, shark conservation.


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