Dear all,
We are pleased to announce the publication of the following article:
Rabearisoa, N., Sabarros, P.S., Romanov, E.V., Lucas, V., Bach, P.,
2018. Toothed whale and shark depredation indicators: A case study from
the Reunion Island and Seychelles pelagic longline fisheries. PLOS ONE
13, e0202037. https://doi.org/10.1371/journal.pone.0202037
**Abstract**
Depredation in marine ecosystems is defined as the damage or removal of
fish or bait from fishing gear by predators. Depredation raises concerns
about the conservation of species involved, fisheries yield and
profitability, and reference points based on stock assessment of
depredated species. Therefore, the development of accurate indicators to
assess the impact of depredation is needed. Both the Reunion Island and
the Seychelles archipelago pelagic longline fisheries targeting
swordfish (Xiphias gladius) and tuna (Thunnus spp.) are affected by
depredation from toothed whales and pelagic sharks. In this study, we
used fishery data collected between 2004 and 2015 to propose depredation
indicators and to assess depredation levels in both fisheries. For both
fisheries, the interaction rate (depredation occurrence) was
significantly higher for shark compared to toothed whale depredation.
However, when depredation occurred, toothed whale depredation impact was
significantly higher than shark depredation impact, with higher
depredation per unit effort (number of fish depredated per 1000 hooks)
and damage rate (proportion of fish depredated per depredated set). The
gross depredation rate in the Seychelles was 18.3%. A slight increase of
the gross depredation rate was observed for the Reunion Island longline
fleet from 2011 (4.1% in 2007–2010 and 4.4% in 2011–2015). Economic
losses due to depredation were estimated by using these indicators and
published official statistics. A loss of 0.09 EUR/hook due to
depredation was estimated for the Reunion Island longline fleet, and
0.86 EUR/hook for the Seychelles. These results suggest a southward
decreasing toothed whale and shark depredation gradient in the southwest
Indian Ocean. Seychelles depredation levels are among the highest
observed in the world revealing this area as a “hotspot” of interaction
between pelagic longline fisheries and toothed whales. This study also
highlights the need for a set of depredation indicators to allow for a
global comparison of depredation rates among various fishing grounds
worldwide.
This is an open access publicationavailable from:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202037
Any request can be made to njaratiana.rabeari...@ird.fr
Cheers,
Njaratiana
--
Njaratiana RABEARISOA
IRD UMR 248 MARBEC, Ob7
Station Ifremer
Avenue Jean Monnet, CS 30171
34203 Sète cedex
Tél : +33 (0)4 99 57 32 04
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