March 2016

Huge numbers of the large Sea Hares, Aplysia punctata, were discovered on the shore at Runswick Bay, North Yorkshire  "They are all over the shore, not just in rockpools, we had to be very careful not to step on them!"
They have also been found at Filey Brigg, Selwick Bay, Flamborough Head, South Bay Scarborough, Selwicks, South Landing and Boggle Hole, all on the Yorkshore coast. The first ones were found in November 2015.

The interesting and newsworthy aspect of this prevalence is that occurrences in these vast numbers are are highly variable from year to year.  Only in rare years are the spawning agggregations seen in such enormous numbers.

10 November 2014

A huge Sea Hare,Aplysia, laying eggs was discovered at Belcroute on the south coast of Jersey. It weighed in at a massive 900 grams which ruled out the normal species Aplysia punctata found around the shores of Britain. Its huge bulk and appearance almost certainly means it is the southern species Aplysia fasciata which is only rarely recorded around the Channel Islands with at least one record off Cornwall and others from Devon and Dorset. It was 30 cm in length.

8 April 2008
 

– Return adult Aplysia depilans to pool marked with ‘X’ and at the same time find another Aplysia depilans in the same pool, which appears larger than the one I am returning.  Photograph them together.  Photo above.

Notes:  The two Aplysia depilans are arrowed.  Within minutes of taking the photo attached to this email, the tide reached the pool and inundated it with turbid, grey water.  The water is more turbid this year than last, perhaps because of the storms in March.  Many tide pools are covered in a layer of fine particles which quickly produce a cloud of clay and silt when one walks in them.  There has been excessive harvesting of verm and razor clams from Belle Greve Bay during the last two years.  There are very few of these animals left inter-tidally.  Where ever the bait diggers have dug they have loosened the soil to such an extent that when I step on this loosened soil (by mistake) I can descend into it a foot or more.

6 April 2008
– Find adult Aplysia depilans in pool marked with ‘X’ on aside aerial view photo.  Collect Aplysia for home photography and weighing.  It weighed 236 grams.

22 February 2008
– Find Aplysia depilans egg strings in pool marked with ‘X’. (photo above)

The last boulder I turned over revealed the Aplysia depilans photographed above.
The Aplysia depilans was bigger than my fist and it was attached to the bottom of a boulder.

When I picked it up it did not produce any ink at all unlike Aplysia punctata.  When I first turned the boulder over I thought it was the holdfast of a Furbelows.  It had a similar colour and was about the same size.

There were large numbers of Aplysia on the Belle Greve Bay shore this afternoon and this surprised me as last year I didn’t see them until much later in the year.

I brought the Aplysia depilans home to photograph in an aquarium.  It has a broad, dark red/brown foot unlike Aplysia punctata, which has a narrow foot and is yellowish white.  The Aplysia depilans specimen weighed 162 grams live weight.  I returned it to Belle Greve Bay this afternoon and photographed some Aplysia punctata for comparison and to satisfy myself that my Aplysia depilans identification is correct.

I handled some Aplysia punctata and they didn’t ink me either.

16 October 2007
Large Helford Sea Hares
Tony Sutton was diving on the eelgrass bed at 5.7metres depth in the Helford Voluntary Marine Conservation Area, Cornwall, when he came across some exceptionally large greenish brown sea-hares (35 cm) which attracted his attention. When he returned a few days later with his camera he was able to take some excellent pictures which indicated the species Aplysia depilans. Confirmation of this identification was established by Dr Paul Gainey when one of the animals was taken briefly from the water.

Photographs by Doug Herdson

A specimen of 30 to 35 cm and weighing 1.5 kg was caught in Poole Bay, Dorset, just outside of Poole Harbour in a trammel net by John Green of the FV. Serendipity. It was caught in 3 - 4 metres of water on sand on a flooding tide, while fishing for sole and bass. Subsequently a further four large sea hares have been caught by fishermen in the same area.
It was brought into the National Marine Aquarium at Plymouth where it is now on show as our "Feature Creature" in our recently refurbished Shallow Waters, Hidden Depths exhibit, where it is devouring very large quantities of sea lettuce Enteromorpha latuca.
Previously, only six specimens of this southern species of sea hare have been recorded in British seas.

1800s - several in the Channel Islands
15/02/1949 - Salcombe Estuary
8/07/1971 - Galway Bay, Ireland
2/08/1971 - Killary Bay, Ireland
Late 70s or early 80s - Exmouth Beach, Devon
1990 - Gillan Creek, Helford, Cornwall
1997? - Saltstone, Salcombe Estuary, Devon

i.e. only six in the last hundred years.

Sea Hare, Aplysia fasciata

Aplysia, the size if which (between 30 & 35 cm) indicates that it is Aplysia fasciata. It was photographed swimming in Helford River, Cornwall. It was seen by Steve Potter.

I am also keen to hear of any other records of these two large
species of Aplysia. The only ones I am aware of for Aplysia
fasciata prior to August of this year are:

1800s - several in the Channel Islands
15/02/1949 - Salcombe Estuary
8/07/1971 - Galway Bay, Ireland
2/08/1971 - Killary Bay, Ireland
Late 70s or early 80s - Exmouth Beach, Devon
1990 - Gillan Creek, Helford, Cornwall
1997? - Saltstone, Salcombe Estuary, Devon

i.e. only six in the last hundred years.

You may be interested in the info I have gathered for the media -

Aplysia fasciata at the National Marine Aquarium

A specimen of 30 to 35 cm and weighing 1.5 kg was caught in Poole
Bay, Dorset, just outside of Poole Harbour on 14th October 2007, in
a trammel net by John Green of the FV. Serendipity. It was caught
in 3 - 4 m of water on sand on a flooding tide, while fishing for
sole and bass. Subsequently a further four large sea hares have
been caught by fishermen in the same area.

It was brought into the National Marine Aquarium where it is now on
show as our "Feature Creature" in our recently refurbished Shallow
Waters, Hidden Depths exhibit, where it is devouring very large
quantities of sea lettuce Enteromorpha latuca.

Aplysia fasciata is the largest and the rarest of the three species
of sea hare found in the British Isles. It is an Atlantic species,
found from the Channel to Angola (South west Africa and to Brazil)
and also throughout the Mediterranean. It appears to reach its
northern limit in Ireland and along the Channel coast of England.
It is one of the largest sea slugs in the world. The other two
British species are the relatively common Aplysia punctata variable
in colour and growing to 20 cm; and the uncommon Aplysia depilans
with different shaped back lobes, brown or green and growing to a
maximum of 30 cm.

There were several in the Channel islands in the mid 1800s, but the
first one in mainland Britain was found on the Saltstone in Salcombe
Estuary, Devon, at extreme low water in February 1949. Another was
found at the same place in 1997. They are very rare but have also
been found in Ireland and Cornwall. This year from late August to
mid October, a number of individuals have been found from south west
Cornwall to Dorset and in Jersey. Several were washed up on two
beaches on the south Devon coast (described as "purple, slug-like,
up to the size of a rugby ball"), and egg masses have been found in
a sheltered inlet.

They are impressive animals growing to 40 cm and weighing up to 2
kg. Most found in Britain have been smaller, but the specimen from
Poole was a large one of 30 to 35 cm and 1.5 kg.

While called sea slugs they are very different from garden slugs,
being some of the most spectacular and beautiful of molluscs.

The sea hares have a small thin internal shell, largely covered by
the large wing-like body flaps (parapodial lobes) which also protect
their gills. These give it a bat-like appearance when swimming.
They vary from bright red to brown in colour, have a clear head,
tiny eyes and have two pairs of tentacles, the larger of which look
like rabbit's ears. It is these tentacles along with its large size
and rounded body shape that give it a rabbit-like look and
consequently its common name. When stressed they release a purple
ink into the water which is contains the toxin opaline. The animals
are said to be mildly toxic but are eaten in some areas of the
world.

Most sea slugs feed on other animals including sea anemones, but the
sea hares are vegetarians preferring seaweed.

They come inshore to breed, most usually in the Spring. Each sea
hare is both male and female being a simultaneous hermaphrodite.
They are known to form long mating chains each animal being a male
to the one in front of it and female to the one behind. The penis
is on the side of the head just below the right anterior (cephalic)
tentacle. They then lay a pink to orange chain of eggs forming
large spaghetti-like masses at the bottom of the shore or in shallow
water. The young hatch from these, spend some time as a veliger
larva in the plankton and them settle on algae as a tiny 1-2 mm sea
hare. They grow rapidly reaching full size in a year, before
breeding and dying.

They are a rare southern species but a combination of climatic
conditions appear to have brought quite a few to our southern shores
this year. This is probably a one-off occurrence. There is no
reason at present to link it to climate change, though it could be
related to changes in oceanic currents.

Abridged:
Aplysia fasciata is the largest and the rarest of the three species of sea hare found in the British Isles. It is an Atlantic species, found from the Channel to Angola (South west Africa and to Brazil) and also throughout the Mediterranean. It appears to reach its northern limit in Ireland and along the Channel coast of England.
It is one of the largest sea slugs in the world. The other two British species are the relatively common Aplysia punctata variable in colour and growing to 20 cm; and the rare (in British seas) Aplysia depilans with different shaped back lobes, brown or green and growing to a maximum of 30 cm.

• 21 September 1998
• A Sea Hare, Aplysia depilans, floated into St. Peter Port harbour, Guernsey, British Channel Islands on September 21.  It weighed 242 grams and was 147 mm long and  80 mm wide.  The parapodia (conspicuous lateral lobes) of Aplysia depilans are fused posteriorly.
•  
• Aplysia depilans
•  

This is the first A. depilans I have seen although in June and July of this year I saw at least one hundred of the commoner A. punctata either spawning on seaweed or washed up on Guernsey beaches.  (Report by Richard Lord from Guernsey, EMail:fishinfo@guernsey.net).