July 15, 2016
The Atlantic Walrus Nutritive Base Research
The Marine Research center specialists in collaboration with the Polar Expedition Kartesh project with the assistance of the Marine Mammal Council carried out research on the condition of the Atlantic walrus nutritive base. The research was conducted as part of the optimal Red Book Atlantic walrus condition and preservation research strategy program. The results of the expedition will specify the distribution of the basic benthic communities and nutritive resources of the Atlantic Walrus in the Pechora Sea.
The research location corresponds to the walrus haulout areas on the western coast of Vaygach Island and the eastern coast of Matveev Island. The research range was specified together with the Marine Mammal Council based on the series of their observations and tracking of the animals’ migration via satellite tags installed between 2011 and 2015. The research range covered the offshore area between Matveev, Vaygach, Dolgy islands, and cape Skahanin of Yuzhny Island of Novaya Zemlya; it corresponded to the areas of massive walrus agglomerations.
We had two objectives. The first one was to assess the condition and to forecast the macrozoobenthic community dynamics, as it is the basic prey item of a walrus. The objective implied description and quantitative characteristics of communities, specifically species and taxonomy composition, species occurrence, number of species, as well as the distribution of dominant species across the area. The second objective was to assess the nutritive reserves of the Atlantic walrus within the given water area by defining the number and biomass as well as characteristics and distribution of the key nutritive resource – large bivalve mollusks.
In the period from July 9 to July 12 we covered 19 stations with depth ranging from 10 to 60 meters. At each station we took three samples with a grab-sampler (Ocean-0.1 and Ocean-0.25) with the sampling surface of 0.1 m2 and 0.25 m2 correspondingly. We visually defined filling ratio of a grab sampler and the nature of a bottom sediment. Apart from that, we separately sampled filter-feeding bivalves tissue to assess the level of pollution of the benthic communities.
Additionally, we conducted underwater video recording of the sea bottom at 15 stations with a “SuperGNOM Pro” ROV to analyze the soil and assess the megafauna, which cannot be extracted with a sea grabber. The procured data will allow to make assertions about the density of mega- and macrozoobenthos in addition to the quantitative data of the bottom-grab recordings.
We expectthe processed data to allow us to revise the quantitative characteristics of the research region benthic communities, to assess the ecosystem condition and offer an optimal monitoring strategy in view of the bottom landscape, soil characteristics and mass forms of the invertebrates.
Relying on the results of biodiversity, biomass and other ecological characteristics of the walrus nutritive resources assessment, we will be able to forecast the condition and dynamics of the biocommunity and to specify qualitative characteristics and distribution of the basic benthic species, which are a part of the walrus nutritive base, and develop a macrozoobenthos regular eco-monitoring program in the areas of massive walrus aggregations.
Preliminary results of the research however indicate that the locations within the maximum satellite tag data aggregation cannot be characterized as ultimately productive. Thus, a vast number of questions, linked with the species research methodology and the walrus nutritive behavior aspects, arise. We expect a huge amount of work.
We need to develop an inclusive research program and attract marine mammal specialists to characterize walrus diet specifics, and the background of its nutritive base more accurately; it will be more accurate to forecast and assess nutritive resources and (to certain extent) the human impact on the given ecosystems.
Polar Expedition Kartesh Project Head Deputy for marine biology and ecology,
LMSU Marine Research Center CEO