[MARMAM] New paper: Humpback dolphin bycatch in shark nets

Shanan Atkins shanan at vodamail.co.za
Tue Jan 29 00:27:55 PST 2013

Dear MARMAM list subscribers
We are pleased to let you know about our new publication: Atkins, S., Cliff,
G., & Pillay, N. (2013). Humpback dolphin bycatch in the shark nets in
KwaZulu-Natal, South Africa. Biological Conservation, 159, 442-449.

Humpback dolphins (Sousa plumbea) in South Africa are classified as
Vulnerable and one quantifiable threat is accidental mortality in the shark
nets in KwaZulu-Natal. We investigated the spatial, temporal and life
history patterns of this bycatch to guide mitigation strategies to decrease
humpback dolphin capture. A total of 203 individuals were caught between
1980 and 2009. We analysed patterns of captures in relation to the area of
capture (location) and year and month of retrieval from the nets. We also
analysed the distribution of the sex and size (body length) of humpback
dolphins. Most catches (61%) occurred at Richards Bay in the northern part
of their distribution in South Africa. Annual catch rate fluctuated
considerably and there was little seasonality. The sex ratio was male-biased
(1.55:1) and in particular skewed towards adolescents (56%) which
constituted the majority of the catch. We suggest that mitigation strategies
be focused at Richards Bay, throughout the year. Of the existing shark net
mitigation strategies, changing fishing gear from nets to baited hooks
(drumlines) could be useful to decrease humpback dolphin capture rates.

PDFs can be requested from shanan at vodamail.co.za
<mailto:shanan at vodamail.co.zaBest> 
Best wishes

Shanan Atkins

 <mailto:shanan at vodamail.co.za> shanan at vodamail.co.za



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