The sea pens Virgularia mirabilis, Pennatula phosphorea and Funiculina quadrangularis: distribution and conservation issues in Scottish waters

Abstract

The sea pens Virgularia mirabilis, Pennatula phosphorea and Funiculina quadrangularis: distribution and conservation issues in Scottish watersThe distributions of the pennatulid anthozoans (sea pens) Virgularia mirabilis, Pennatula phosphorea and Funiculina quadrangularis in Scottish waters have previously only been extensively documented in sea lochs, by the Marine Nature Conservation Review (MNCR) surveys. Funiculina quadrangularis in particular was thought to be restricted to the deep basins of sea lochs and is classified as a nationally uncommon species. Sea pens are characterizing species in seven biotopes found in Scottish waters and are protected under the 'Mud in Deep Water Habitat Action Plan' of the UK Biodiversity Action Plan (UKBAP) and are also recorded in several Special Areas of Conservation. The present study has extended the existing information available on sea pens in Scottish waters. The distribution and abundance of the three sea pen species were mapped using GIS (Geographical Information System) by utilizing data from Nephrops norvegicus stock assessment video surveys carried out by Fisheries Research Services (FRS) Marine Laboratory. Distribution was shown to be aggregated for all species. Funiculina quadrangularis was present in areas outside the sea lochs, such as the South Minch and the outer mouths of most sea lochs. This study demonstrates that analysis of video footage derived from Nephrops stock assessment surveys can significantly extend our knowledge of sea pen distribution and population density. Future management of Nephrops stocks can be expected to consider impacts of fishing on non-commercial species such as sea pens as a part of the 'ecosystem approach' to management.

Sea pen (Pennatulacea) aggregations on the northern Spanish shelf: distribution and faunal assemblages

“…was more abundant, while on the outer shelf the sediments are sandier and have low organic content (López-Jamar et al 1992). Nevertheless, Greathead et al (2007) suggest that depth is a more important factor than sediment type in the distribution of F. quadrangularis.…”

“…was abundant from 100 to 200 m, while the few occurrences of F. quadrangularis were mainly between 200 and 300 m. Hughes (1998) and Greathead et al (2007) also suggest the preference of F. quadrangularis for deeper habitats where the conditions may be more stable. In addition, also relating depth to sediment particle size and organic content, finer and organic-rich sediments have been reported on the inner shelf off the Rías Bajas (Galicia, Spain), where Pennatula spp.…”

“…Techniques such as beam trawl and demersal otter trawl are often used in benthic community studies, although monitoring is extensively recommended for the management of sea pens and burrowing megafauna (Hughes 1998, Greathead et al 2007). Monitoring and assessment of vulnerable habitats have been carried out in the area with non-destructive monitoring techniques such as remotely-operated vehicles and photogrammetric sledges (Aguilar et al 2009, www.ecomarg.com, Sánchez et al 2009), but they were short-term or spatially isolated studies.…”

“…Moreover, in contrast with other corals, they are able to anchor in soft sediment (Hughes 1998), offering a shelter in a bare environment and acting as an indicator of the degradation of these sediments, which commonly sustain intensive fishing pressure or other disturbances (Thrush and Dayton 2002). The OSPAR Convention assessed the threatened habitat "sea pen and burrowing megafauna communities" in the northeast Atlantic affected by Nephrops trawling (Hughes 1998, Greathead et al 2007, OSPAR 2010. Moreover, sea pens are involved in the soft-bottom coral garden habitat that is also considered threatened and/or declining (OSPAR 2008).…”

Cold Temperate Coral Habitats

“…Bottom trawling is known to be one of the most destructive ways of fishing and causes reductions in habitat complexity, changes in species composition, and reductions in biodiversity [7][8][9]. These threats highlight that it is crucial to assess the ecological importance of these deepwater communities, to develop sound scientific advice for management of cold-water ecosystems [10,11].…”