Understanding the Distribution of Marine Megafauna in the English Channel Region: Identifying Key Habitats for Conservation within the Busiest Seaway on Earth

The temperate waters of the North-Eastern Atlantic have a long history of maritime resource richness and, as a result, the European Union is endeavouring to maintain regional productivity and biodiversity. At the intersection of these aims lies potential conflict, signalling the need for integrated, cross-border management approaches. This paper focuses on the marine megafauna of the region. This guild of consumers was formerly abundant, but is now depleted and protected under various national and international legislative structures. We present a meta-analysis of available megafauna datasets using presence-only distribution models to characterise suitable habitat and identify spatially-important regions within the English Channel and southern bight of the North Sea. The integration of studies from dedicated and opportunistic observer programmes in the United Kingdom and France provide a valuable perspective on the spatial and seasonal distribution of various taxonomic groups, including large pelagic fishes and sharks, marine mammals, seabirds and marine turtles. The Western English Channel emerged as a hotspot of biodiversity for megafauna, while species richness was low in the Eastern English Channel. Spatial conservation planning is complicated by the highly mobile nature of marine megafauna, however they are important components of the marine environment and understanding their distribution is a first crucial step toward their inclusion into marine ecosystem management

Index of marine megafauna biodiversity.

<p>Colour scale indicates number of umbrella groups (large pelagic fish, cetaceans, marine turtles, seabirds and pinnipeds) present per cell where warmer colours point to hotspots.</p

Northern gannet distributions.

<p>Empirical observations and Maxent predictions of probable and suitable habitat (left to right) in spring (A), summer (B), autumn (C), and winter (D). Warmer colours in middle plots indicate a higher probability of presence.</p

Study area.

<p>The study regions of the English Channel and North Sea indicated by dashed lines. Depth contours (30 and 100 m) in light grey. Areas <30 m are white.</p

Stranding summaries.

<p>Graphical summaries of strandings' composition (pie chart), effort-uncorrected trends (country-specific, time-series duration indicated by dotted lines along x-axis) and status (main bar chart), and cause (bar chart on far right) for marine turtles (top) and cetaceans (bottom).</p

Harbour porpoise distributions.

<p>Empirical observations (left column) and Maxent predictions of probable (middle column) and suitable habitat (right column) in spring (A), summer (B), autumn (C), and winter (D). Warmer colours in middle plots indicate a higher probability of presence.</p

Auk distributions.

<p>Empirical observations and Maxent predictions of probable and suitable habitat (left to right) in spring (A), summer (B), autumn (C), and winter (D). Warmer colours in middle plots indicate a higher probability of presence.</p

Dolphin distributions.

<p>Empirical observations and Maxent predictions of probable and suitable habitat (left to right) in spring (A), summer (B), autumn (C), and winter (D). Warmer colours in middle plots indicate a higher probability of presence.</p