Feeding ecology of capelin (Mallotus villosus) in a fjord impacted by glacial meltwater (Godthåbsfjord, Greenland)
Capelin (Mallotus villosus) is an important trophic node in many Arctic and sub-Arctic ecosystems. In Godthåbsfjord, West Greenland, the zooplankton community has been shown to change significantly from the inner part of the fjord, which is impacted by several glaciers to the shelf outside the fjord. To what extent this gradient in zooplankton composition influences capelin diet during their summer feeding in the fjord is yet unknown. To investigate this, we analysed stomach content of capelin (8–14 cm) sampled using a pelagic trawl at three stations in outer (GF3), mid (GF7) and inner (GF10) part of Godthåbsfjord in May and August 2013. In May, the copepod nauplii numerically dominated the diets, but euphausiids contributed > 92% by carbon mass at all stations. In August, calanoid copepods were the most important prey numerically and by carbon mass. Smaller copepod species became more important towards the inner stations, whereas the large Calanus species dominated in the outer stations. There was also a trend in decreasing stomach carbon content towards the inner stations, and on the individual level, variation in stomach content was strongly negatively related to the proportion of small copepods in the diet. This suggests that the inclusion of small copepods in the diet cannot compensate for the absence of larger euphausiids and copepods. Therefore, any change in the ecosystems that favours these at the expense of larger zooplankton and euphausiids is likely to impact capelin feeding negatively with consequences for the whole ecosystem.
KeywordsCapelin Zooplankton Diet Glacial meltwater Greenland Climate
We gratefully acknowledge the contributions of the Arctic Research Centre (ARC), Aarhus University. Support was also provided by the Canada Excellence Research Chair (CERC). Financial support was provided by the Greenland Self-government and the Greenland Climate Research Centre (GCRC). We acknowledge the MarineBasis-Nuuk programme, part of the Greenland Ecosystem Monitoring (GEM), for contributing to the sample collection. Data from the Greenland Ecosystem Monitoring Programme were provided by the Greenland Institute of Natural Resources, Nuuk, Greenland in collaboration with Department of Bioscience, Aarhus University, Denmark. This work is a contribution to the Arctic Science Partnership (ASP) and GEM. The authors thank the crew of the RV ‘Sanna’ for sampling assistance
Funding was provided by Greenland Self-government and Greenland Climate Research Centre (GCRC).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
Human and animal studies
All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.
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