Helene Thorstensen (UiO) collected genetic samples on a snow crab cruise, but she also had time to have fun.

Snow crab changes species composition and function in benthic animals

NORWAY
Wednesday, January 13, 2021, 20:00 (GMT + 9)

The EISA (Ecology and Management of Invasive Snow Crab) project has been running for a year and a half and focuses on snow crabs in the Barents Sea.

The project studies the following conditions:

1.     Effects on the community of organisms on the seabed of the snow crab
2.     The dynamics of the snow crab population in the Barents Sea and where the crab comes from
3.     What predictions can we make regarding the spread and impact on ecosystems, especially in a future characterized by changing environmental conditions due to climate change?

The project began in 2019 with a "kickoff" meeting and the appointment of Helena Michelsen as Post Doc. A 12-day cruise was then carried out in the middle of the Barents Sea. The cruise was a great success collecting epifauna and infauna samples along a snow crab density gradient, as well as samples for molecular analysis of stomach contents and population genetic studies.

Sediment washing on deck during the EISA cruise (Photo: Christian Skauge)

The situation generated by COVID-19 in 2020 offered several delays due to closed laboratories and canceled trips. Despite this, the project has progressed and several exciting results. The samples of infauna and epifauna that were collected on the cruise have been completed. In areas with lots of snow crabs, the EISA team found changes in the species composition and function of the benthic animals. The most important findings are that the number of species was somewhat lower, the distribution and number of individuals changed and that in areas with a lot of snow crab there were fewer visible signs of the type of alteration of the bottom sediment that contributes to oxygen in the sediment due. that the crab has grazed bottom animals.

In collaboration with researchers around the world, the project has compiled reference genomes from various populations of snow crabs. These reference genomes will be used in population genetic studies to compare samples from the Barents Sea with other geographic areas. This fall, DNA was also extracted from the stomachs of crabs and the results of this are expected to be ready in early 2021. In this way, we can get one step closer to solving the riddle of where the snow crab comes from and find out what species of animals they eat.

Researchers study the color of the bottom sediment on the EISA cruiser (Photo: Christian Skauge)

Modeling work that will assess the spread and effects of snow crab on the food web now and in the future during various climate changes is also underway. The data, time series, and maps that form the basis of the modeling work are collected from reports and from various research institutions and experts. The project works with the goal of having all models up and running during the summer of 2021. Overall, all the EISA project partners are very satisfied with the progression and look forward to a productive 2021.

The national partners in the EISA project are Akvaplan-niva (project manager), NIVA, UiT Norwegian Arctic University and the Institute for Marine Research. The international partners are CSIC Spain and the University of British Columbia, Canada.

Source:Paul Renaud/ Akvaplan-niva (translated from original in norwegian)

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