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A cascade of warming impacts brings bluefin tuna to Greenland waters - MacKenzie - 2014 - Global Change Biology - Wiley Online Library

A cascade of warming impacts brings bluefin tuna to Greenland waters - MacKenzie - 2014 - Global Change Biology - Wiley Online Library

Bluefin tuna were captured in east Greenland waters (Denmark Strait) in August 2012. This location is far beyond the northern limit of their usual summer feeding areas and their capture here is the first report of their presence in these waters. The tuna were likely attracted by exceptionally warm sea temperatures in the region, which also stimulated a key tuna prey species, Atlantic mackerel, to enter the region. Warm conditions have been leading a trophic cascade into the region and altering foodwebs and predator-prey interactions.
The key biological interactions are shown in the journal cover image, which was prepared by Glynn Gorick (copyright G. Gorick and DTU AQUA).
Primary Research Article

Article first published online: 13 MAY 2014

DOI: 10.1111/gcb.12597

© 2014 John Wiley & Sons Ltd

Issue

Volume 20, Issue 8, pages 2484–2491, August 2014

Additional Information

MacKenzie, B. R.(1,2), Payne, M. R.(2), Boje, J.(3), Høyer, J. L.(4) and Siegstad, H.(5) (2014), A cascade of warming impacts brings bluefin tuna to Greenland waters. Global Change Biology, 20: 2484–2491. doi: 10.1111/gcb.12597

1) Center for Macroecology, Evolution and Climate, National Institute for Aquatic Resources (DTU Aqua), Technical University of Denmark, Charlottenlund, Denmark

2) Center for Ocean Life, National Institute for Aquatic Resources (DTU Aqua), Technical University of Denmark, Charlottenlund, Denmark

3) National Institute for Aquatic Resources (DTU Aqua), Technical University of Denmark, Charlottenlund, Denmark

4) Danmarks Meteorologisk Institut, Copenhagen Ø, Denmark

5) Greenland Institute for Natural Resources, Nuuk, Greenland

*Correspondence: Brian R. MacKenzie, tel. +4535883445; fax +4535883333, email: brm@aqua.dtu.dk

Rising ocean temperatures are causing marine fish species to shift spatial distributions and ranges, and are altering predatorprey dynamics in food webs. Most documented cases of species shifts so far involve relatively small species at lower trophic levels, and consider individual species in ecological isolation from others. Here, we show that a large highly migratory top predator fish species has entered a high latitude subpolar area beyond its usual range. Bluefin tuna, Thunnus thynnus Linnaeus 1758, were captured in waters east of Greenland (65°N) in August 2012 during exploratory fishing for Atlantic mackerel, Scomber scombrus Linnaeus 1758. The bluefin tuna were captured in a single nethaul in 9–11 °C water together with 6 tonnes of mackerel, which is a preferred prey species and itself a new immigrant to the area. Regional temperatures in August 2012 were historically high and contributed to a warming trend since 1985, when temperatures began to rise. The presence of bluefin tuna in this region is likely due to a combination of warm temperatures that are physiologically more tolerable and immigration of an important prey species to the region. We conclude that a cascade of climate change impacts is restructuring the food web in east Greenland waters. 


 
 
 
 
 
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