Evidence for seasonal cycles in deep-sea fish abundances: A great migration in the deep SE Atlantic?

Autor: Milligan RJ; Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.; Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, Dania Beach, FL, USA., Scott EM; School of Mathematics and Statistics, University of Glasgow, Glasgow, UK., Jones DOB; National Oceanography Centre, Southampton, UK., Bett BJ; National Oceanography Centre, Southampton, UK., Jamieson AJ; School of Natural and Environmental Science, Newcastle University, Newcastle Upon Tyne, UK., O'Brien R; BP Exploration Operating Company Limited, Sunbury on Thames, UK., Pereira Costa S; BP Angola (Block 18) BV, BP International Centre for Business & Technology, Sunbury on Thames, UK., Rowe GT; Texas A&M University at Galveston, Galveston, TX, USA., Ruhl HA; National Oceanography Centre, Southampton, UK.; Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA., Smith KL Jr; Monterey Bay Aquarium Research Institute, Moss Landing, CA, USA., de Susanne P; BP Angola (Block 18) BV, BP International Centre for Business & Technology, Sunbury on Thames, UK., Vardaro MF; School of Oceanography, University of Washington, Seattle, WA, USA., Bailey DM; Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK.
Jazyk: angličtina
Zdroj: The Journal of animal ecology [J Anim Ecol] 2020 Jul; Vol. 89 (7), pp. 1593-1603. Date of Electronic Publication: 2020 Apr 11.
DOI: 10.1111/1365-2656.13215
Abstrakt: Animal migrations are of global ecological significance, providing mechanisms for the transport of nutrients and energy between distant locations. In much of the deep sea (>200 m water depth), the export of nutrients from the surface ocean provides a crucial but seasonally variable energy source to seafloor ecosystems. Seasonal faunal migrations have been hypothesized to occur on the deep seafloor as a result, but have not been documented. Here, we analyse a 7.5-year record of photographic data from the Deep-ocean Environmental Long-term Observatory Systems seafloor observatories to determine whether there was evidence of seasonal (intra-annual) migratory behaviours in a deep-sea fish assemblage on the West African margin and, if so, identify potential cues for the behaviour. Our findings demonstrate a correlation between intra-annual changes in demersal fish abundance at 1,400 m depth and satellite-derived estimates of primary production off the coast of Angola. Highest fish abundances were observed in late November with a smaller peak in June, occurring approximately 4 months after corresponding peaks in primary production. Observed changes in fish abundance occurred too rapidly to be explained by recruitment or mortality, and must therefore have a behavioural driver. Given the recurrent patterns observed, and the established importance of bottom-up trophic structuring in deep-sea ecosystems, we hypothesize that a large fraction of the fish assemblage may conduct seasonal migrations in this region, and propose seasonal variability in surface ocean primary production as a plausible cause. Such trophic control could lead to changes in the abundance of fishes across the seafloor by affecting secondary production of prey species and/or carrion availability for example. In summary, we present the first evidence for seasonally recurring patterns in deep-sea demersal fish abundances over a 7-year period, and demonstrate a previously unobserved level of dynamism in the deep sea, potentially mirroring the great migrations so well characterized in terrestrial systems.
(© 2020 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.)
Databáze: MEDLINE
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