On March 5 started a new meeting of U.S.-Russian Marine Mammal Working Group in Seattle, USA and ended on March 7. We took our chance to represent the results of the Commander Islands Reserve Science Department work.
In the beginning of March the 24th meeting of Marine Mammal Working Group took place. The group is acting in the framework of Area V of Agreement between the Government of the United States of America and the Government of the Russian Federation on Cooperation in the Field of Protection of the Environment and Natural Resources signed on June 23, 1994. The cooperation between the two countries in the field takes its origins on May 23, 1972, when the first agreement was signed. Therefore, the 1st meeting of the Working Group was organized in October 1973. Since then, the meetings are held on a regular basis once every two years to discuss joint research projects and to share scientific data to increase the efficiency of population control and protection of marine mammals registered in both countries.
Northern fur seal is the most numerous marine mammal of the Commander Islands Nature and Biosphere Reserve
The Commander Islands Reserve is a home for tens of marine mammals’ species and we take part in the Working Group in different forms. This year we participated in absentia. The Science Department of the reserve prepared a number of presentations, which depict the results of marine mammals monitoring in two past years. The contributions concentrated on northern fur seal, harbor seal and sea otter monitoring and were presented during the session.
Northern fur seal pup is also called "black".
Rookeries of the Commander Islands are traditional areal for one fifth of the global population of the northern fur seal. Therefore, the importance of monitoring on the islands is evident. Previous full population counts were held in 2011. Last year we shared the work of Science Department, which uses quadrotors for counts on rookeries.
Photos make pups counts easier
In 2017 we conducted fur seal pups counts on all the four reproductive rookeries. Around 60 000 pups was born and the total population of the fur seal on the islands is estimated at 200 000 individuals. After 1978 – the year of the highest population numbers – we see a gradual decrease. Today the numbers are stable or decreasing moderately. The decrease is seen in the whole areal of the species.
Northern fur seal population dynamics on the Commander Islands in 1957-2017
Last year our team has also conducted counts of harbor seal population – species included in the Red Data Book of Russia. We used a new method, which consists in counting animals on photos made by a quadrotor.
Harbor seal counts with use of quadrotor
This method was used for the first time ever for the harbor seals group on the Commander Islands and gave us data on the number of pups. The counts were made on all the haulouts on Bering and Topokov Islands. For the other islands we used the extrapolation method to discover the overall numbers.
Harbor seal haulout on the reefs
The total population of the harbor seal on the islands is estimated at about 4 000 individuals with 22% of pups. Today it is hard to analyze the dynamics throughout the time, because the previous data need to be processed, as they were collected with different methods.
A newborn harbor seal pup
As for sea otter data, we presented information collected in 2016. The research of the water area around the islands gives us a possibility to estimate the number of sea otters at 3 650 individuals. The number is still low after the decrease, which started in 2009, and now is comparable with the level registered in the 80s.
The sea otter population density off the coasts of the Commander Islands
The data we sent to be presented during the Working Group is a part of the whole work of our scientific team in the field of marine mammal research on the Commander Islands. Modern methods and technologies open new horizons for future research and raise marine mammal monitoring on a new level.