Seals in the Solent
The Wildlife Trusts South East Marine Conservation Manager, Jolyon Chesworth, gave a talk on our local seal population and how we can help look after them.
Solent seal traces
Seals are some of the most charismatic animals you can see in this country, the Solent area is home to a small but regionally unique population of seals.
There are two species of seals resident in the UK.
Grey seals tend to prefer rocky, exposed areas and so are more common in the South West and off the coasts of Wales and Scotland.
Seals are the largest predators we have in the UK, they can eat over 5% of their body weight each day and prey on a variety of creatures including flatfish, roundfish and even crabs, using their whiskers to help forage in the murky waters. When seals are not busy feeding, they rest on mud and sand banks, called haul-out sites, when the tide is out, although they do sometimes sleep at sea. When the tide comes in the seals move off to feed although they rarely travel more than about 60km from their haul-out sites to forage. However, occasionally they are known to travel further afield and a seal from Cherbourg was tracked swimming across the Channel to the Solent and along the coast to Kent!
UK home to 40% of harbour seals.
The UK is home to approximately 40% of the global population of harbour seals, however, in some places these populations are declining by as much as 50%, with serious implications for their survival. Nobody yet understands what may be contributing to these declines but all agree we need to increase our monitoring to get a better understanding. With the Solent population being so small, they are potentially very vulnerable. As a result, the South East Wildlife Trusts and Chichester Harbour Conservancy initiated a project to find out more about our local seal population.
Very little was known about the Solent seals, they are thought to have been living in the area for several decades, however it wasn’t until 1994 when people started recording their numbers, back then they were able to count just three! Regular counts continue and the population has increased over time to around 16-20. However, we had no idea as to where their most important sites were for resting, feeding and breeding. If these sites are not identified then we can’t protect them and therefore can’t protect the seals.
The data received from the tags has been hugely informative. We have now identified all of their haul-out sites, the most important of which are in Langstone and Chichester Harbours. We have also located 15 foraging grounds that are in regular use, they predominantly feed in the eastern Solent from Southampton Water to Selsey Bill. They regularly cross the Solent to the Isle of Wight, visiting Bembridge and Ryde.
The widest ranging seal swam to Worthing on a three day trip, sleeping at sea and diving down to depths of 60m. They have also been found to hold their breath for up to 25 minutes when feeding. This information is crucial if we are to ensure that the areas that the seals rely upon are considered in management and conservation plans and fed in to development proposals that may affect them.
We have a code of conduct on our website that should be followed when observing seals. Canoeists should aim to keep 50m away from seals, however, some animals can be very curious and we have had several reports of seals swimming right up to kayaks, mouthing toggles and even trying to clamber on, which when you consider they weigh over 100kg, can be a little disconcerting!
Seeing a seal resting on the shore or playing in the water is one of the great wildlife watching experiences you can have in this country. The work of the project will help ensure that seeing a seal in the Solent will remain a possibility for future generations.
Although the tags have given us an excellent understanding of our local seal population, they have now fallen off, so we are gathering data in other ways. We are very keen to receive any sightings of seals and have an online recording form on the website that you can fill in and submit.
For further information see the website:
Grey seal with 'roman nose'
Harbour seals (sometimes called common seals), as their name suggests, prefer sheltered harbours and estuaries. It is harbour seals that are most frequently found in the Solent due to the sheltered nature of our coast, although there are a couple of grey seals in the area as well.
Studying seals is a tricky business, they can range many kilometres to feed and spend significant amounts of time underwater, the best way is to deploy the latest technology. In March 2009 we attached GPS tracking devices to five harbour seals, these instruments are essentially mobile phones with a built in GPS to provide location data. They also provide information on seal diving behaviour such as depth of dive and dive duration. Once attached they last about 5 months until the seals moult and the tags fall off.
Harbour seal with 'dog' shaped nose
Distinguishing between the two species can be tricky, especially if seen from a distance or the seals are young. The easiest way is to look at the head and muzzle shape, grey seals have a ‘roman nose’ with no distinct forehead, harbour seals have a more dog shaped head with a distinct forehead separating their muzzle from their head.