Field Reports

Monday 31st July  2017 - Seal Walk

Leader John Arnott

 

On a luckily dry day, 31 enthusiastic people (including 15 non-members) set off with the hope of seeing our local seals. John had calculated that, with a neap tide, this would be a prime time and we were not disappointed.

As we reached Marker Point we could make out grey humps – were they rocks or seals? Further on and with telescopes and binoculars out and John’s expertise, we could clearly make out 32 common or harbour seals (including pups) and 5 grey seals. 

As we gazed (simultaneously enjoying our picnics) we learnt more – A common seal was first noted in the harbor in 1993 but they had probably been about before that. In 2009, 17 common and a couple of grey seals were recorded. Oar rithe is their main haul out with other satellite haul outs at Nutbourne Marsh and in Langstone Harbour. In June, July, August and September each year, numbers are recorded and on 17th July this year, 43 common and 4 grey seals were in Chichester Harbour and 3 common and 2 grey in Langstone.

Common seal pups arrive in June/July and are able to swim from birth. They proceed to grow very quickly, being weaned after just 4 weeks. (Note - for a period of 3-4 weeks in August/September the adults moult and grow new fur. They prefer to stay out of the water at this time as their blood will then flow closer to the skin surface and follicles, aiding hair growth – making it a great time to count them.)

Grey seal pups, however, are born in the Autumn/Winter, at progressive times around the british coast, starting in the SW England and proceeding clockwise, with Blakeney in Norfolk peaking in January. These pups have long white hair and cannot swim, which means they and their mums are land bound, with the mum having to fast for 17 – 18 days while she feeds the pup with milk that has 60% fat (common seals only slightly less at 45% fat). John told us that a grey seal mum loses approx. 4 kgs in weight per day (the equivalent of 131 Mars bars!) These grey seal pups are then abandoned (with no knowledge of how to swim/ catch food!) while the adults mate and return to the water. As a result, nowhere is safe enough for grey seals to breed in Chichester Harbour.

However, Great Britain is very important, having 38% of the world’s population of grey seals, with 80% of those in Scotland. This year, approx. 1000 grey seals were seen at Blakeney (in 2006 it was 213). Promise to self - must visit Blakeney.

It is interesting that when 5 seals (4 male and 1 female) were tagged in Chichester Harbour, they were recorded as visiting as far as Southampton Water, the I.O.W. and one all the way to Shoreham.

Many thanks go to John from everyone who attended, for telling us more about our local seal population and rewarding us with a very special sight. 

As a foot note, ruddy darter and emperor dragon flies were seen en route. Also noted were holly blue, common blue, gatekeeper, meadow brown, small heath and small copper (thank you, Philippa). 

Gill Hance

 

John telling us about the Seals in the harbour.
Golden Samphire (Limbarda crithmoides)

        Golden Samphire
 

Female Ruddy Darter

       Female Ruddy Darter 
 

Seals in Chichester Harbour

       Seals at their main haul out
 

Chichester, West Sussex

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