Thursday, September 13, 2012

IUCN Shark Specialist Group on the Oceanic Whitetip Shark


The IUCN, or International Union for Conservation of Nature, recently published the report from their Species Survival  Commission Shark Specialist Group.  The report can be downloaded in it’s entirety here.

Here’s an excerpt from their section on Oceanic Whitetip Sharks.  It’s scary to see the dramatic reduction of animals throughout the oceans, particularly what’s happening in the Nothwest and Western Central Atlantic.  The regional data their suggests a 99.3% reduction of the Oceanic Whitetip population over just the past 40 years.  While data varies in quality and there is not doubt insufficient data for precise measurements, fishing pressures need to be dramatically reduced while these calculations are fine-tuned.  The current pace is moving at a terrifyingly unsustainable pace.

Global: Vulnerable
The Oceanic Whitetip Shark (Carcharhinus longimanus) is a formerly widespread and abundant large oceanic shark subjected to fishing pressure virtually throughout its range. It is caught in large numbers as a bycatch in pelagic fisheries, with pelagic longlines, probably pelagic gillnets and handlines, and occasionally pelagic and even bottom trawls. Catches, particularly in international waters, are inadequately monitored. Its large fins are highly prized in international trade although the carcass is often discarded. Fishery pressure is likely to persist if not increase in the future. Outside of the areas detailed below, this species is under similar fishing pressure from multiple pelagic fisheries and there are no data to suggest that declines have not also occurred in these areas, given there are similar fisheries throughout the range. As such, a precautionary global assessment of Vulnerable is considered appropriate for the Oceanic Whitetip Shark. Efforts are underway to improve the collection of data from some regions and effective conservation and management of this species will require international agreements.

Northwest & Western Central Atlantic: Critically Endangered
The Oceanic Whitetip Shark is assessed as Critically Endangered in the Northwest and Western Central Atlantic because of the enormous declines that have been reported. Two estimates of trends in abundance from standardized catch rate indices were made from independent datasets. An analysis of the U.S. pelagic longline logbook data between 1992 and 2000, which covers the Northwest and Western Central Atlantic regions, estimated declines of 70%. An analysis of the Gulf of Mexico, which used data from U.S. pelagic longline surveys in the mid-1950s and U.S. pelagic longline observer data in the late-1990s, estimated a decline of 99.3% over this 40 year time period or 98% over three generations (30 years). However, changes in fishing gear and practices over this time period were not fully taken into account in the latter analysis, and there is currently debate as to whether or not these changes may have resulted in an under- or overestimation of the magnitude of these declines.
Published by:  IUCN Species Survival Commission Shark Specialist Group, Vancouver, Canada.
Copyright: © 2012 IUCN Species Survival Commission Shark Specialist Group.


...visit epicdiving.com for more pictures of Oceanic Whitetip Sharks



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