Aspects of the life history of the Atlantic poacher, Leptagonus decagonus, in Svalbard waters

Abstract

The aim of the study is to describe aspects of the life history of the Atlantic poacher (Leptagonus decagonus) obtained during early October 2010 and late September 2011 from the Hinlopen Strait, located between Nordaustlandet and the Spitsbergen Archipelago. Length was measured for 142 individuals, and 82 out of these were weighed, sexed and the age in years determined. The sex distribution in the population was 45% females and 55% males. Gut content examination revealed the domination of the mesopelagic and hyper−benthic calanoid Bradyidius similis that was recorded in 87% of the stomachs analysed. Overall there was a significant difference in size (length and weight) between the sexes, and a difference in length and weight at age between the sexes. There was no difference in age distribution between the sexes, but there was a larger age range within the male population than in the female population. The sexual dimorphism in size is likely linked to different reproductive strategies. This study represents the first data on the life history of the Atlantic poacher in Svalbard waters.