Page 145 - Alderney Regional Environmental Assessment of Renewable Energy: Environmental Report

Alderney Regional Environmental Assessment of Renewable Energy:
Environmental Report
Distribution and Abundance Around Alderney
No minke whale sightings were recorded in any of the recent monitoring surveys around
Alderney (ARE, 2009; Entec UK Limited, 2007; Alderney Wildlife Enterprise, 2011). The
species is therefore only likely to occur rarely in the Alderney area.
Grey Seal (Halichoerus grypus)
The grey seal is the larger of the two seal species found in British waters, with males reaching
a length of 2.45m and weigh over 300kg (SCOS, 2012). Grey seals predominantly inhabit
remote islands and coastline, breeding on undisturbed beaches of cobble and boulders or
within sea-caves along the coast. Pupping time occurs primarily from August through to
December with September generally being the busiest month. About 38% of the world
population of grey seals is found in Britain and over 88% of British grey seals breed in
Scotland, the majority in the Hebrides and in Orkney (SCOS, 2012).
Distribution and Abundance in the English Channel
Grey seals are on the southernmost limit of their range in the Northern France area. Colonies
of grey seals are also located along the coast of Brittany and Normandy (Molène archipelago,
Sept Îles archipelago, the Baie du Mont Saint Michel and the Baie de Somme) with a combined
population of approximately 105 grey seals (Härkönen et al. 2007).
In the Baie du Mont Saint Michel and the Baie de Somme, haul-out site numbers are small with
a maximum of about ten individuals typically recorded in each bay seasonally. In the Sept Îles
archipelago, numbers varied between 10 and 20 in the period 1997 to 2000 with data
suggesting numbers have increased since then. During the same period, the number of seals
hauling out in the Molène archipelago varied between 30 and 65 individuals (Härkönen et al.
2007.
Seals from these sites have shown evidence of regularly visiting other colonies in the Channel
Islands, Southwest England and Wales indicating that grey seals in France do not constitute a
separate population (Härkönen et al. 2007; Vincent et al. 2005). For example, individual
movements from the main colony of the Molène archipelago were assessed by using Satellite
Relay Data Loggers (SRDLs). Sixteen wild seals were tracked from 1999 to 2003. Fourteen
seals left the archipelago, of which 9 crossed the English Channel to Southwest England,
Wales, or the Channel Islands (Vincent et al. 2005). Two out of 4 rehabilitated juvenile grey
seals released in the vicinity of the Molène archipelago in 1997 also crossed the Channel, with
1 seal visiting a grey seal colony in South-east Ireland (Vincent et al. 2002). Overall, more than
half of the 20 seals tracked from western Brittany visited other grey seal colonies overseas
(Härkönen et al. 2007).
Distribution and Abundance Around the Channel Islands and Cotentin Coast
Small numbers of grey seals haul-out at sites on the Channel Islands. For example, a small
colony is also situated on the Humps off the north coast of Herm which comprises
approximately 3-8 individuals (GREC, 2011).
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