How do cephalopods become available to seabirds: can fish gut contents from tuna fishing vessels be a major food source of deep-dwelling cephalopods?

Abstract

Xavier, J. C., Cherel, Y., Roberts, J., and Piatkowski, U. 2013. How do cephalopods become available to seabirds: can fish gut contents from tuna fishing vessels be a major food source of deep-dwelling cephalopods? – ICES Journal of Marine Science, 70:46–49. Cephalopods are important prey for numerous seabird species. However, the physical mechanisms by which cephalopods (particularly species considered as deep-dwelling) become available to seabirds are poorly understood, and it has recently been suggested that the discarded stomachs of gutted fish captured by tuna longliners can be a major source of deep-dwelling species. Here, we identify some deep-dwelling cephalopods that appear in the diet of seabirds, review the current knowledge of their vertical distribution, and compare the stomach contents of commercially captured tuna with those of seabirds foraging in the same area. The limited available information leads us to conclude that tuna longliners are unlikely to be a major source of deep-dwelling cephalopods for seabirds. However, much more information is required on the ecology of seabird prey, particularly commercially unexploited cephalopod species, which may be obtained from scientific cruises devoted to cephalopod biological research. In addition multispecies/foodweb modelling studies may be required to explore potential interactions between seabirds, their predators and prey, and commercial fishing operations.

Biogeography of Cephalopods in the Southern Ocean Using Habitat Suitability Prediction Models

“…Further, the absence of a prey item from a 119 predator's diet may be due to factors such as availability (e.g. deep prey beyond the diving 120 reach of air-breathing predators) or prey preference, rather than disjunct spatial distributions 121 (Xavier et al, 2013). 122…”

The significance of cephalopod beaks in marine ecology studies: Can we use beaks for DNA analyses and mercury contamination assessment?

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From Ice to Penguins: The Role of Mathematics in Antarctic Research

“…application of such methods (Xavier et al 2003a;Xavier et al 2005;Xavier et al 9! 2007;Xavier et al 2011;Xavier et al 2013b;Xavier et al in press).…”