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Cook Inlet belugas still not recovering National Marine Fisheries Service survey from summer 2016 indicates continuing low population with long-term downward trend Alan Bailey Petroleum News
The National Marine Fisheries Service has published the results of its summer 2016 aerial survey of Cook Inlet beluga whales. An analysis of the survey data has indicated a whale population of about 328. That lies within the population range of 284 to 375 whales estimated since 2006 and is consistent with a decline rate of about 0.5 percent per year during that period. However, the decline rate has fallen since 1999, when management of subsistence hunting of the whales began, the Fisheries Service says.
The Cook Inlet beluga whales form a distinct, isolated subpopulation of the belugas found around the Alaska coast. A sharp decline in the Cook Inlet whale population between 1994 and 1998, thought to be a consequence of the over-harvesting of the whales, led eventually in 2008 to the Cook Inlet belugas being listed as endangered under the Endangered Species Act. However, although regulation of the hunting began in 1999 and hunting of the animals ceased entirely after 2005, the beluga population has not rebounded as had been anticipated. The reason for the whales’ continuing misfortune remains an enigma.
Began in 1993 The Fisheries Service has been conducting summer beluga whale aerial surveys since 1993. The agency conducted these surveys annually until 2012, since when the surveys have been conducted biennially. The surveys involve flying a team of observers in a high-wing aircraft around the inlet at an altitude of around 800 feet. The surveys both follow the complete Cook Inlet coastline and use sawtooth patterns across the inlet. Multiple surveys are conducted across areas where belugas are consistently found. Video footage of the surveyed areas provides a further source of population counts. The Fisheries Service team uses statistical techniques to infer actual population sizes and size uncertainties from the observation data.
One curious finding from an analysis of survey results over the years is that the region of Cook Inlet in which the beluga whales are observed in the summer has gradually shrunk. In fact, in the 2016 survey whales were only observed in the more northerly part of upper Cook Inlet and in Turnagain Arm - no belugas were observed in lower Cook Inlet, in Knik Arm or in upper Cook Inlet south of North Foreland and Moose Point, the Fisheries Service says. In the late 1970s, on the other hand, Belugas were observed as far south as Kasilof on the Kenai Peninsula and Tuxedni Bay on the west side of the inlet, as well as in much of Knik Arm.
Satellite tagging of whales confirms the summer distribution of whales that has been observed from the aerial surveys, the Fisheries Service says.
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