Abundance and distribution of the harbour porpoise (Phocoena phocoena) on the north coast of Anglesey, Wales, UK

Abstract

A three year study was undertaken during 2002 to 2004 from May to September to estimate abundance and density of harbour porpoises on the north coast of Anglesey, Wales, UK. There were no ecological data regarding the harbour porpoises in Anglesey waters so the ability to influence conservation measures was highly constrained.Boat based transects using distance sampling techniques were applied so a robust estimate of density and abundance could be attained. The study area consisted of a block approximately 489 km2 extending from the east of Point Lynas to the west of South Stack on north coast of Anglesey. The study area was divided into 5 blocks consisting of 31 perpendicular transect lines to the shore. Each of the transect lines were surveyed 1–5 times by the end of the three year study.Based on the assumption that g(0) = 1 the density of harbour porpoises for the 489 km2 study site was estimated to be 0.630 individuals/km2 (CV = 0.20) and the abundance is estimated to be 309 individuals (CV = 0.20). Heterogeneity in density and abundance was observed across the 5 blocks which showed Point Lynas and South Stack to have the highest densities. This distribution was closely associated to fine-scale oceanographic features which cause prey to be concentrated and may facilitate foraging for harbour porpoises. The study showed that Anglesey provides coastal habitats for the harbour porpoise and was the first study of this kind in North Wales, UK.

Habitat preferences and distribution of the harbour porpoise Phocoena phocoena west of Scotland

“…A similar preference for water over 50 m depth has been recorded in other studies around the region (MacLeod et al 2007, Goodwin & Speedie 2008, Marubini et al 2009, Isojunno et al 2012. Depth has also been an important predictor in other studies further afield, though the preferred depths have varied considerably (Raum-Suryan & Harvey 1998, Carretta et al 2001, Tynan et al 2005, Shucksmith et al 2009. The habitat preference observed here could be explained by the availability of prey species in these regions.…”

Habitat preferences and distribution of the harbour porpoise Phocoena phocoena west of Scotland

“…A similar preference for water over 50 m depth has been recorded in other studies around the region (MacLeod et al 2007, Goodwin & Speedie 2008, Marubini et al 2009, Isojunno et al 2012. Depth has also been an important predictor in other studies further afield, though the preferred depths have varied considerably (Raum-Suryan & Harvey 1998, Carretta et al 2001, Tynan et al 2005, Shucksmith et al 2009. The habitat preference observed here could be explained by the availability of prey species in these regions.…”

Predictions from harbor porpoise habitat association models are confirmed by long-term passive acoustic monitoring

“…Consequently, we were unable to determine whether harbor porpoises in the Moray Firth are associated with areas of high tidal strength or areas around islands which other studies have shown to be important (Marubini et al, 2009;Shucksmith et al, 2009;Embling et al, 2010). Instead, as expected from studies of other predators in this region (Mudge and Crooke, 1986;Greenstreet et al, 1998), we found high numbers of harbor porpoise sightings over areas such as the Smith Bank, which are likely to contain suitable habitat for potential prey such as sandeels (Hopkins, 1986;ICES, 2007).…”

“…Harbor porpoises Phocoena phocoena are widely distributed across European waters (Reid et al, 2003), occurring in a variety of habitats that range from offshore sandbanks in open waters (Hammond et al, 2002;Todd et al, 2009) to complex tidal streams around island archipelagos (Marubini et al, 2009;Shucksmith et al, 2009;Embling et al, 2010). Their protected status under the European Habitats Directive (ECC, 1992), frequent interactions with fisheries (e.g., Vinther and Larsen, 2004;Leeney et al, 2008), and use of areas identified for offshore energy developments (Bailey et al, 2010b;Thompson et al, 2010;Scheidat et al, 2011) have led to a number of studies that have used habitat association modeling to identify key management areas (Bailey and Thompson, 2009;Embling et al, 2010).…”

Distribution and Abundance of the East Asian Finless Porpoise in the Coastal Waters of Shandong Peninsula, Yellow Sea, China

“…The assumption that g ( 0 ) = 1, implying that all animals are detected directly on the trackline, is a critical premise of line transect sampling [22]. However, in practice, we could hardly detect groups that were under the surface, and we may even have missed some of the surfacing groups on the trackline; thus, g ( 0 ) < 1 [25,26]. Consequently, the estimates presented here could be considered conservative.…”

Habitat preferences and distribution of the harbour porpoise Phocoena phocoena west of Scotland

“…A similar preference for water over 50 m depth has been recorded in other studies around the region (MacLeod et al 2007, Goodwin & Speedie 2008, Marubini et al 2009, Isojunno et al 2012. Depth has also been an important predictor in other studies further afield, though the preferred depths have varied considerably (Raum-Suryan & Harvey 1998, Carretta et al 2001, Tynan et al 2005, Shucksmith et al 2009. The habitat preference observed here could be explained by the availability of prey species in these regions.…”

Predictions from harbor porpoise habitat association models are confirmed by long-term passive acoustic monitoring

“…Consequently, we were unable to determine whether harbor porpoises in the Moray Firth are associated with areas of high tidal strength or areas around islands which other studies have shown to be important (Marubini et al, 2009;Shucksmith et al, 2009;Embling et al, 2010). Instead, as expected from studies of other predators in this region (Mudge and Crooke, 1986;Greenstreet et al, 1998), we found high numbers of harbor porpoise sightings over areas such as the Smith Bank, which are likely to contain suitable habitat for potential prey such as sandeels (Hopkins, 1986;ICES, 2007).…”

“…Harbor porpoises Phocoena phocoena are widely distributed across European waters (Reid et al, 2003), occurring in a variety of habitats that range from offshore sandbanks in open waters (Hammond et al, 2002;Todd et al, 2009) to complex tidal streams around island archipelagos (Marubini et al, 2009;Shucksmith et al, 2009;Embling et al, 2010). Their protected status under the European Habitats Directive (ECC, 1992), frequent interactions with fisheries (e.g., Vinther and Larsen, 2004;Leeney et al, 2008), and use of areas identified for offshore energy developments (Bailey et al, 2010b;Thompson et al, 2010;Scheidat et al, 2011) have led to a number of studies that have used habitat association modeling to identify key management areas (Bailey and Thompson, 2009;Embling et al, 2010).…”

Distribution and Abundance of the East Asian Finless Porpoise in the Coastal Waters of Shandong Peninsula, Yellow Sea, China

“…The assumption that g ( 0 ) = 1, implying that all animals are detected directly on the trackline, is a critical premise of line transect sampling [22]. However, in practice, we could hardly detect groups that were under the surface, and we may even have missed some of the surfacing groups on the trackline; thus, g ( 0 ) < 1 [25,26]. Consequently, the estimates presented here could be considered conservative.…”

Habitat preferences and distribution of the harbour porpoise Phocoena phocoena west of Scotland

“…A similar preference for water over 50 m depth has been recorded in other studies around the region (MacLeod et al 2007, Goodwin & Speedie 2008, Marubini et al 2009, Isojunno et al 2012. Depth has also been an important predictor in other studies further afield, though the preferred depths have varied considerably (Raum-Suryan & Harvey 1998, Carretta et al 2001, Tynan et al 2005, Shucksmith et al 2009. The habitat preference observed here could be explained by the availability of prey species in these regions.…”

Predictions from harbor porpoise habitat association models are confirmed by long-term passive acoustic monitoring

“…Consequently, we were unable to determine whether harbor porpoises in the Moray Firth are associated with areas of high tidal strength or areas around islands which other studies have shown to be important (Marubini et al, 2009;Shucksmith et al, 2009;Embling et al, 2010). Instead, as expected from studies of other predators in this region (Mudge and Crooke, 1986;Greenstreet et al, 1998), we found high numbers of harbor porpoise sightings over areas such as the Smith Bank, which are likely to contain suitable habitat for potential prey such as sandeels (Hopkins, 1986;ICES, 2007).…”

“…Harbor porpoises Phocoena phocoena are widely distributed across European waters (Reid et al, 2003), occurring in a variety of habitats that range from offshore sandbanks in open waters (Hammond et al, 2002;Todd et al, 2009) to complex tidal streams around island archipelagos (Marubini et al, 2009;Shucksmith et al, 2009;Embling et al, 2010). Their protected status under the European Habitats Directive (ECC, 1992), frequent interactions with fisheries (e.g., Vinther and Larsen, 2004;Leeney et al, 2008), and use of areas identified for offshore energy developments (Bailey et al, 2010b;Thompson et al, 2010;Scheidat et al, 2011) have led to a number of studies that have used habitat association modeling to identify key management areas (Bailey and Thompson, 2009;Embling et al, 2010).…”

Distribution and Abundance of the East Asian Finless Porpoise in the Coastal Waters of Shandong Peninsula, Yellow Sea, China

“…The assumption that g ( 0 ) = 1, implying that all animals are detected directly on the trackline, is a critical premise of line transect sampling [22]. However, in practice, we could hardly detect groups that were under the surface, and we may even have missed some of the surfacing groups on the trackline; thus, g ( 0 ) < 1 [25,26]. Consequently, the estimates presented here could be considered conservative.…”