Seamount seascape composition and configuration shape Southwest Indian Ridge fish assemblages

Swanborn, D.J.B.; Huvenne, V.A.I. ORCID: https://orcid.org/0000-0001-7135-6360; Malpas, T.; Pittman, S.J.; Rogers, A.D.; Taylor, M.L.; Woodall, L.C.. 2022 Seamount seascape composition and configuration shape Southwest Indian Ridge fish assemblages. Deep Sea Research Part I: Oceanographic Research Papers, 103921. 10.1016/j.dsr.2022.103921

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Official URL: http://dx.doi.org/10.1016/j.dsr.2022.103921

Abstract/Summary

Seamounts are commercially important fishing grounds. Yet, little is known about their physical characteristics as fish habitat, important for informing conservation and ecosystem-based management. This study examines how multiscale seabed spatial heterogeneity influences commercially important fish families at three Southwest Indian Ridge seamounts (Coral Seamount, Melville Bank and Atlantis Bank). We quantified seascape heterogeneity from bathymetry and geomorphological habitat maps and identified 15 focal fish families from video data. Fish-habitat associations were examined using spatial pattern metrics that measured terrain morphology, seascape composition (variety and relative abundance of patch types) and seascape configuration (spatial arrangement of patches). Broader seascape context was characterised by geographic location and water depth. Multivariate regression trees and random forests modelled fish-habitat associations and identified the most influential explanatory variables. Assemblage characteristics and individual families were strongly influenced by geographic location and depth, and at finer scales (500 m buffers) seascape composition and configuration helped explain fish-habitat associations. Spatially continuous summit habitat and complex shaped ridge features supported high abundance and diversity of commercial fish families. Metrics of seascape composition and configuration (i.e., habitat size, shape and structural connectivity) had higher predictive power than the terrain metrics commonly used in developing proxies for deep-water fish species and biodiversity. These outcomes indicate that seascape metrics, commonly applied on land and in shallow marine environments, are also relevant environmental predictors of fish distributions in deep-sea environments. We highlight strong context dependency and depth-specific associations that hinder attempts to draw wider generalisations on fish-seascape linkages for seamounts.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.dsr.2022.103921
ISSN:	09670637
Date made live:	23 Nov 2022 13:53 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/533608

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.dsr.2022.103921

ISSN:

09670637

Date made live:

23 Nov 2022 13:53 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/533608