Distribution, Population Biology, and Trophic Ecology of the Deepwater Demersal Fish Halosauropsis macrochir (Pisces: Halosauridae) on the Mid-Atlantic Ridge

• Published in: PLoS ONE
• Main Authors: Bergstad, Odd Aksel, Clark, Laura, Hansen, Hege Ø., Cousins, Nicola
• Format: Article in Journal/Newspaper
• Language: English
• Published: PLoS ONE 2012
• Subjects: demersal fish; bunnfisk; stock assessment; bestandsberegning; sampling; prøvetaking; distribution; utbredelse; VDP::Mathematics and natural science: 400::Geosciences: 450::Oceanography: 452; VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923; VDP::Social science: 200::Library and information science: 320::Knowledge retrieval and organization: 323; VDP::Mathematics and natural science: 400::Mathematics: 410::Analysis: 411; Mid-Atlantic Ridge; Iceland; North Atlantic
• Online Access: http://hdl.handle.net/11250/109238; https://doi.org/10.1371/journal.pone.0031493

Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700–3500 m. All sizes, ranging from 10–76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2–36 years, but most individuals were ,20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size.