Diet of the blue marlin, Makaira nigricans, off the south coast of Portugal

Abstract

The blue marlin, Makaira nigricans (Istiophoridae), is a large, top predator with a worldwide distribution whose feeding ecology is still unknown in the northeast Atlantic. The stomach contents of 24 Atlantic blue marlin, caught by the Big Game fishing fleet (between 2007 and 2010) off the south coast of Portugal, were studied. All marlin fed exclusively on pelagic fish, with a total of 180 prey items recorded, belonging to 6 identified species. The most important family in the blue marlin diet was Scombridae, representing 70% of the total prey items. Among the Scombridae, the chub mackerel, Scomber colias, was the most important prey species (47.9% by weight, 51.1% by number, 58.3% by frequency of occurrence). The length of prey found in the stomachs ranged from 136 to 727 mm in length, and a significant positive correlation was found between prey and blue marlin size. Our results suggest that in this geographical area (NE Atlantic) marlin feed on a small spectrum of species, with a preference for foraging on seamounts.

Keywords:

• Billfishes
• diet
• Makaira nigricans
• northeast Atlantic
• Portugal

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

The authors would especially like to thank Big Game Clube de Portugal (in particular Mr. Augusto Figueira) for their support, and all the Big Game anglers of the Algarve who provided the specimens. Many thanks also to all the Coastal Fisheries Research Group researchers, for all their support and valuable ideas. This study was supported by a PhD grant awarded to Pedro Veiga by the ‘Portuguese Foundation for Science and Technology (FCT)’: PhD grant (SFRH/BD/28723/2006). José Xavier was also supported by the FCT.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark