title: Spatio-temporal variability in the cannibalistic behaviour of European hake Merluccius merluccius: the influence of recruit abundance and prey availability.
abstract: Cannibalistic behaviour of European hake Merluccius merluccius was studied through the analysis of 49 836 gut contents belonging to individuals from 6 to 82 cm in total length (L(T)). Samples were collected every autumn between 1993 and 2009. The results showed that the consumption of conspecific individuals was consistent over space and time. The abundance, spatial distribution patterns and L(T) structure of M. merluccius recruits were the main variables involved in M. merluccius cannibalism. A geographical pattern was found since increasing cannibalism was observed in areas of recruit aggregations. The L(T) spectrum of recruits in autumn was also a key factor and dependent on the spawning period. When adults spawned from late spring to summer, an increasing cannibalism trend was found in autumn, due to the ideal size structure of the prey (M. merluccius recruits) for predators. Depth was also a significant variable, and a cannibal peak was detected at depths ranging between 50 and 200 m, coinciding with a spatial overlap of predator (pre-adults) and prey (recruits). The cannibalistic behaviour of M. merluccius began at c. 12 cm, although 75% were mid-sized individuals between 16 and 30 cm. Additionally, 90% of prey-hake were recruits <18·5 cm. Some biological and ecological aspects such as growth rate, spawning period, predation and competition interactions and the effect of some oceanographic events on M. merluccius cannibalism are also discussed.
authors.affiliation: IEO Centro Oceanográfico de Santander, Promontorio San Martín, s/n, P. O. Box 240, 39080 Santander, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Preciado
authors.forename: A
authors.initials: A
authors.lastname: Punzón
authors.forename: F
authors.initials: F
authors.lastname: Velasco
mesh_terms: D000818:Animals; D049628:Body Size; D002190:Cannibalism; D020387:Food Chain; D048388:Gadiformes / Q000502:physiology*; D005766:Gastrointestinal Contents; D011235:Predatory Behavior; D012621:Seasons; D062211:Spatio-Temporal Analysis
keywords: density; feeding behaviour; recruitment; southern Bay of Biscay