This paper presents data on the diet of the musky octopus, Eledone moschata, caught with bottom-trawl nets in the northern Adriatic Sea from October 2001 to June 2003. A total of 1226 stomachs were examined, out of which 34.8% were empty. Several indices were used to describe the diet of the species. Crustaceans were found to be the most important prey category and their remains occurred in 65.0% of stomachs with food. Fish and cephalopods were present in 37.8% and 21.8% of stomachs, respectively. Differences in food composition between smaller and larger individuals were observed. In specimens with mantle lengths up to 80 mm crustaceans dominated, occurring in 79.4% of examined stomachs. Important prey categories of the larger specimens (>80 mm) were crustaceans, fish and cephalopods. No significant differences in the diet between males and females were found. Cannibalism occurred only occasionally and at larger sizes. Seasonal changes in the diet were observed, but seasonality did not seem to be a limiting factor in the feeding intensity of the species. Results indicate that the observed differences in the diet composition and feeding dynamics of the musky octopus are primarily due to the animals' changes in size.

A specimen of the musky octopus, Eledone moschata, of 188 mm mantle length and 1414 g total body weight, was caught on 12 February 2007 by trammel net in İzmir Bay. The given sizes are the maximal for this species at the present time.

Domoic acid (DA), the toxin responsible for the illness known as amnesic shellfish poisoning (ASP), is an algal toxin produced naturally by some species of the diatom genus Pseudo-nitzschia. The toxin has been detected in a diverse array of marine organisms from copepods to whales. Cephalopods, which are important members of the food chain and active predators of known toxin vectors such as bivalves, crabs and some fishes, have just recently been implicated in DA transfer or accumulation. Here we present data showing detectable values of DA determined by HPLC-UV (high-performance liquid chromatography and ultraviolet detection) and confirmed by HPLC-MS (mass spectrometric detection) in two octopus species collected along the Portuguese continental coast: Eledone cirrhosa and E. moschata. Domoic acid was frequently detected in the digestive gland of E. moschata and occasionally reached concentrations exceeding 100 µg g−1. In contrast, E. cirrhosa contained lower concentrations of DA on the few occasions that it was detected. This suggests that E. moschata is a potential vector for DA transfer to higher trophic levels in the coastal marine food web, not excluding humans. These data, combined with known aspects of the life history of the species, are a necessary step towards achieving an understanding of the accumulation of phycotoxins in cephalopods.