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Two Arctic seminars on Tuesday 11 October

In connection with the GreenEdge project, two researchers visit Roskilde and present their research

2016.10.07 | Susanna Pakkasmaa

Date Tue 11 Oct
Time 13:30 14:15
Location Pavillion, Roskilde & ARC Meeting room

Mathieu LeBlanc, Université Laval

Pelagic fish assemblage and ecology in the eastern Canadian Arctic in a context of climate change

In the eastern Canadian Arctic, the ice-free season is lengthening, while anthropogenic activities are increasing. However, fish communities of the region are poorly documented, even though they are part of the intermediate trophic levels and thus play a pivotal role in the ecosystem equilibrium.

The main objective of this PhD project is to document the pelagic fish assemblage and ecology in the eastern Canadian Arctic using hydroacoustics and scientific nets. To achieve this objective, a scientific multi-frequency (38, 120 and 200 kHz) echosounder hull-mounted aboard the research icebreaker CCGS Amundsen is operated in the eastern Canadian Arctic since 2004 to detect fish aggregation.

Post-analysis of the acoustic backscatter will allow estimating length, abundance and biomass of pelagic fish along the track of the ship. Ichthyoplankton nets, midwater and benthic trawls will be deployed to document the fish assemblage and to validate the acoustic echoes. This study will contribute to anticipate the impacts of the on-going changes on the Arctic marine ecosystem in a context of climate change and anthropogenic development.

 

Marine Cusa, UiT The Arctic University of Norway

Effects of seasonality and spatial heterogeneity on polar cod (Boreogadus saida) diet and feeding strategy in Svalbard waters

The key Arctic fish species polar cod (Boreogadus saida) is often referred to as an opportunistic feeder yet concerns remain regarding its ability to cope with climate change induced modifications in prey phenology and composition, and with growing competition. A diet analysis could shed the light on polar cod’s plasticity and the extreme seasonal light variations at high latitudes calls for a seasonal dietary examination.

This study focuses primarily on the impact of seasonality on adult polar cod diet and foraging strategy. We hypothesized that adult polar cod feed actively throughout the year but that their feeding success might vary depending on the season and be slightly lower during the polar night. We further hypothesized that adult polar cod’s opportunistic feeding strategy may depend on season and that dietary prey diversity will increase during the polar night because of visual constraints on selectivity of preferred prey. 

 

Read more about the GreenEdge project

Arctic Research Centre