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

Cousins, N.J.; Horton, T. ORCID: https://orcid.org/0000-0003-4250-1068; Wigham, B.D.; Bagley, P.M.. 2013 Abyssal scavenging demersal fauna at two areas of contrasting productivity on the Subantarctic Crozet Plateau, southern Indian Ocean. African Journal of Marine Science, 35 (2). 299-306. https://doi.org/10.2989/1814232X.2013.802747

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

Abstract/Summary

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.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.2989/1814232X.2013.802747
ISSN:	1814-232X
Additional Keywords:	amphipods, Crozet Islands, deep water, marine fish, scavengers
Date made live:	08 Oct 2013 10:25 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/503433

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.2989/1814232X.2013.802747

ISSN:

1814-232X

Additional Keywords:

amphipods, Crozet Islands, deep water, marine fish, scavengers

Date made live:

08 Oct 2013 10:25 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/503433