Demersal Fish Assemblages in NE Atlantic Seagrass and Kelp

Evie Furness,Richard K.F Unsworth

doi:10.3390/d12100366

Abstract

Global fisheries are in decline, calling for urgent evidence-based action. One such action is the identification and protection of fishery-associated habitats such as seagrass meadows and kelp forests, both of which have suffered long-term loss and degradation in the North Atlantic region. Direct comparisons of the value of seagrass and kelp in supporting demersal fish assemblages are largely absent from the literature. Here, we address this knowledge gap. Demersal fish were sampled using a baited camera to test for differences between habitats in (1) the species composition of the fish assemblages, (2) the total abundance and species richness of fishes, and (3) the abundances of major commercial species. Seagrass and kelp-associated fish assemblages formed two significantly distinct groupings, which were driven by increased whiting (Merlangius merlangus) and dogfish (Scyliorhinus canicula) presence in seagrass and higher abundances of pollock (Pollachius pollachius) and goby (Gobiusculus flavescens) in kelp. The abundance, diversity, and species richness did not change significantly between the two habitats. We conclude that seagrass and kelp do support unique demersal fish assemblages, providing evidence that they have different ecological value through their differing support of commercial fish species. Thus, this study improves the foundation for evidence-based policy changes.

Highlights

The United Nations Food and Agriculture Organisations (FAO) estimated in 2015 that more than one third of global fish stocks were being fished at biologically unsustainable levels to support our ever-increasing human population [1,2,3]
The present study aims to provide a comparison of demersal fish species assemblages associated with seagrass and kelp ecosystems around the UK and identify the spatial and seasonal variation within
This study provides clear comparable evidence that both seagrass meadows and kelp forests support fish species of commercial significance; this is of importance, given the dearth of data on fish species-associated with kelp forests, in the NE Atlantic region

Summary

Introduction

The United Nations Food and Agriculture Organisations (FAO) estimated in 2015 that more than one third of global fish stocks were being fished at biologically unsustainable levels to support our ever-increasing human population [1,2,3]. Key to maintaining fishery stocks is understanding the habitats which are essential for supporting them [4,5,6,7] Nearshore ecosystems, such as the brown algae kelp (Laminaria spp.) and the marine angiosperm seagrass (Zostera marina), can be important fish nursery grounds, crucial for maintaining fish stocks [8,9,10,11]. Ribbon-like leaves of seagrass and large blades of kelp rise into the water column, serving to slow water flow through their respective habitats. This relatively benign environment decreases fish energy expenditure, allowing more energy for growth and success [14]

Methods

Results

Discussion

Conclusion