A year ago, scientists from the Commander Islands Nature and Biosphere Reserve published data that show a twofold drop in sea otter population in the last four years. The grant money will be spent to help scientists find the causes of the negative trend and undertake necessary measures to prevent further degradation.

Sea otters were introduced to Bering Island in the early 1970s for the second time in history, which was approximately a hundred years after their extinction in the region due to unsustainable human hunting practices. For the next twenty years the sea otter population was constantly growing, impacting the whole ecosystem. Sea otters caused a population decline of crabs, king crabs, sea cucumbers, and octopuses. Sea urchin biomass dropped a hundredfold.

However, in the beginning of the 21^st century, scientific researchers revealed a twofold decline of the sea otter population in the island from 2007 to 2015. The next round of research proved the negative trend continuing, demonstrating a 54% decline of the population in the period from 2016 to 2019.

“We consider both natural and anthropogenic causes as possible drivers of this negative trend. A biomass shortage and inaccessibility of benthic forage are related to the former. General water pollution and climate change for the latter. The population decline can also be caused by outbreaks of diseases transmitted from pets. There is also some data showing orcas preying on sea otters in the region. We need to scrutinize every hypothesis before making any conclusions. The support from WWF-Russia and Kinder® is very helpful on this matter,” said Yevgeny Mamayev, the Deputy Director of the Commander Islands Nature Reserve.

The scientists of the Nature Reserve plan to run laboratory tests and large-scale research using drones and sonars studying the whole food chain from sea otters to urchins and seaweed. The researchers will map sea otter habitats within the Reserve’s boundaries defining the most vulnerable areas in the sea otter ecosystem.

“In 2020, WWF-Russia and Kinder® granted financial support to study sea otters in the northern Kuril Islands – Shumshu and Paramushir. The sea otter population in that region has been steadily declining for the last decade. This negative trend may be caused by similar phenomena. Thus, it is important to study sea otter population in both the Kuril Islands and the Commander Islands regions,” said Sergey Rafanov, the Director of WWF-Russia Kamchatka/Bering Sea Ecoregional Office.

The main research will be conducted in the summer-fall timeframe. Although the first data will be acquired in July, preliminary results are expected to become public in winter. It may even take several years to reach final conclusions.

As the result of this work, the scientists plan to present suggestions on sea otter conservation (if the population decline is caused by anthropogenic impact) or develop new approaches to population monitoring (if the population decline is caused by natural ecosystem degradation).

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WWF-Russia and Kinder® join efforts to support the Commander Islands Nature Reserve in studying of sea otter population