The megaepifauna of the Dogger Bank (North Sea): species composition and faunal characteristics 1991–2008

Abstract

During a long-term study in the summer months of the years 1991-2008, 176 megaepifaunal species were recorded through a series of beam trawl surveys on a grid of fixed stations on the Dogger Bank (central North Sea). This paper gives a qualitative overview on species composition throughout the research period, determined from samples collected during 15 cruises. In recent years, a number of species with more oceanic distribution patterns (e.g. species from SW British coasts) has been collected. In spite of these newcomers, there was a slight decrease in total species numbers during the research period.

Environmental influence on the bottom and near-bottom megafauna communities of the Dogger Bank: a long-term survey

“…2 exhibit a clear downward trend, at least since the year 2002. This result is further supported by a previously detected decrease in species richness across the research period (Sonnewald and Türkay 2011). Although species richness is not totally identical with biodiversity (Spellerberg and Fedor 2003), it is-together with species abundance-an important measurable key factor.…”

“…This list (with a few exceptions) was published in Sonnewald and Türkay (2011). Only a part of all determined species was considered as generating a quantitative dataset.…”

“…To provide the best possible temperature resolution, surface and water column temperature data collected on our Sonnewald and Türkay (2011). Stations 1, 2 and 19 were abandoned after the first cruise in 1991 due to coarse sediments, being unsuitable for beam trawl sampling cruises were combined with publicly available CTD data provided online by the International Council for the Exploration of the Sea (ICES).…”

“…The Dogger Bank builds the northern end of a ''southern'' species community cluster with its northern edge being adjacent to faunal assemblages typical for the northern North Sea (Frauenheim et al 1989, Jennings et al 1999a. As introduced and summarised in Sonnewald and Türkay (2011), several detailed and ongoing studies concerning the infauna of the Dogger Bank have been undertaken ever since, but concerning the typical faunal assemblages caught by beam trawl, only sparse information was available.…”

Recent spreading of Xandarovula patula (Mollusca: Gastropoda: Ovulidae) towards the central North Sea suggests a link to rising water temperatures

“…It was chosen for long-term monitoring because of its uniform depth and sediment composition, providing an ideal place to study its epibenthic faunal assemblages and associated changes over time. Since 1991, the epifauna is monitored yearly with a 2 m beam trawl (Sonnewald & Türkay, 2011a, 2011b. Due to the fact that until 2009, the surveys were only undertaken during summer, the composition of the epifauna of the Dogger Bank during winter remained unclear.…”