Role of scavenging in a synaphobranchid eel (Diastobranchus capensis, Barnard, 1923), from northeastern Chatham Rise, New Zealand

Scavengers perform an important role in deep-sea ecosystems, recycling carrion. However, scavenged material can be difficult to discern from predation. The synaphobranchid eel Diastobranchus capensis Barnard, 1923, is common bycatch in deep-water fisheries for orange roughy (Hoplostethus atlanticus Collett, 1889) in New Zealand waters. Despite anecdotal reports of scavenging in D. capensis, their ecology and feeding are little known. Scavenged material was estimated to be approximately 39 per cent (by weight) of the diet of D. capensis from northeastern Chatham Rise, New Zealand, from water depths of 1062–1196m. Scavenged material was defined as fragmentary food items from animals and plants either not normally available to the eel, or from animals larger than the eel consuming them (e.g., fish heads and tails, spent squid spermatophores, beaks and tentacle crowns, and seaweed). D. capensis were primarily piscivorous, with the diet supplemented by squid, natant decapods and mysids. The weight or number of food items did not increase with the size of the eel, nor was there any major ontogenetic shift in the composition of the diet. D. capensis probably plays an important role in mid-slope communities, recycling carrion. •We describe the diet of the synaphobranchid eel, Diastobranchus capensis, Barnard, 1923, from New Zealand waters at mid-slope depths.•Up to 39.1% of the diet by weight of D. capensis was estimated to be scavenged material.•Diastobranchus capensis probably plays an important role in the consumption of carrion at mid-slope depths.