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Abyssal scavenging demersal fauna at two areas of contrasting productivity on the Subantarctic Crozet Plateau, southern Indian Ocean

Lookup NU author(s): Dr Benjamin Wigham

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Abstract

The Crozet Plateau is situated below typical high-nutrient, low-chlorophyll (HNLC) waters of the southern Indian Ocean. The area to the east of the Crozet Islands experiences high levels of surface productivity during the austral summer due to natural iron enrichment from terrestrial sources and favourable light conditions. The demersal scavenging fauna at two areas of contrasting productivity, to the east and south of the islands, were investigated using two landers equipped with baited cameras and traps. Five species of scavenging fish were observed along with five groups of invertebrates during a single deployment of the RObust BIOdiversity (ROBIO) lander. Further deployments of the Fish RESPirometry (FRESP) video lander yielded no additional scavenging fish species. A modelled arrival and departure curve for the abyssal grenadier Coryphaenoides armatus suggests a region of low food availability compared to other regions worldwide. The ROBIO-derived abundance estimate for C. armatus of 187 ind. km(-2) is comparable with published trawl-derived estimates. Significantly more amphipods were collected to the south of the islands, which was subject to lower organic matter supply. Reasons for this are unknown but may be due to differing current direction/velocities, or increased fish predation at the enriched site. The numerically dominant amphipod species present was Paralicella caperesca, followed by Eurythenes gryllus and Orchomenella gerulicorbis. A further five species were observed in low numbers, some occurring only once. One, Paracallisoma sp. nov, was a new species.

Publication metadata

Author(s): Cousins NJ, Horton T, Wigham BD, Bagley PM

Publication type: Article

Publication status: Published

Journal: African Journal of Marine Science

Year: 2013

Volume: 35

Issue: 2

Pages: 299-306

Print publication date: 12/08/2013

ISSN (print): 1814-232X

ISSN (electronic): 1814-2338

Publisher: National Inquiry Services Centre

URL: http://dx.doi.org/10.2989/1814232X.2013.802747

DOI: 10.2989/1814232X.2013.802747

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