Rockpooling in Guernsey



 
Sunday, 15 January 2006 was another good day for rock pooling in
Guernsey.

I decided to visit Belle Greve Bay to the north of St. Peter Port. Wind
direction was from the south south-east gusting to 21 mph but declining
throughout the afternoon.  Air temperature was 9 degrees C and there was
no rain.  The wind made photography difficult.

Although the spring tide wasn't very big, 2.0 metres at 1336, the first
boulder I turned over exposed the beautiful yellow and white sea slug,
Limacia clavigera.  I found two small specimens within ten minutes.
Berthella plumula was common and I saw also Jorunna tomentosa.

On 1 January at La Valette I found male worm pipefish, Nerophis
lumbriciformis, carrying eggs.  At Belle Greve on the 15 January I found
on two occasions (six worm pipefish in total) an ovigerous female worm
pipefish escorted by two male worm pipefish with their concave abdomens.
The two males courting for egg delivery were dissimilar in size.  Worm
pipefish arrive on the shore at this time of year to breed.

On a shore of grey silt and shell gravel that is littered with boulders
and cobbles I found many cypris barnacle larvae.  Some of the boulders
were embedded in the substrate.  As I turned the rocks over a pool of
water filled the depression left by the rock.  Floating on this pool
were hundreds of minute golden cypris larvae.

I found one gelatinous scale worm, Alentia gelatinosa, in this area.
Most boulders I turned over had at least one species of scale worm
underneath.

Long-clawed porcelain crabs, Pisidia longicornis, dominate the mobile
fauna on the underside of cobbles and boulders lying on this grey silt.
 

The only broad-clawed porcelain crabs, Porcellana platycheles, I saw
(and they were large) were in a clear upper-shore tide-pool lined with
crustose and branched coralline algae, Codium sp. and Anemonia viridis.
The ratio of broad-clawed to long-clawed porcelain crabs differs from
the rocky shore at La Valette further south. At La Valette broad-clawed
porcelain crabs far outnumber long-clawed porcelain crabs.

On the shore of grey silt and broken shell I saw one gelatinous ribbon
containing rows of eggs belonging to an unknown species of ribbon worm.
This gelatinous matrix of eggs was narrower than the red ribbon worm
eggs seen on the Guernsey shore in March.

I found some interesting ascidians - more small colonies of Botryllus
schlosseri and several individuals that could be indigenous Styela sp.

I collected two elegant Turbonilla sp. mollusc shells - probably
Turbonilla lactea but haven't confirmed id yet.

I saw some mysid shrimp and many palaemonids.

Ps Does anyone know of a key to cypris barnacle larvae?

Best Wishes,
Yours sincerely,
Richard
Richard Lord
Guernsey GY1 1BQ
Email: fishinfo@guernsey.net


On 1 January 2006 ormers (Haliotis tuberculata) with a minimum shell
length of 80 mm could be legally collected from the shores of Guernsey.
 

I had found an ormer of shell length 11.75 cm on 18 October 2005 on the
shore at La Valette on Guernsey's east coast - south of St. Peter Port.
I wanted to find out if this ormer was still under the same rock. I was
not disappointed. (It was under the same rock.) This is the second
time I have found an ormer in the autumn which has remained under the
same rock through to the New Year. I did not collect it but hope it
survives the ormer collecting season which continues during large spring
tides until the end of April. Because of weather conditions I saw only
one ormer gatherer at La Valette and after he left I found only about a
dozen large boulders overturned.

Low tide was about 1.3 metres at 1339. Wind mean direction was
North-west (320°) and mean wind speed was 20 knots with gusts up to 31
knots. Air pressure was about 1008 mb and air temperature was 8.9 °C.
There were occasional showers. Light levels were low. 

Even with these conditions I saw more variety of animal life than I
usually see during the summer months.

The first cobble I turned over revealed three large male Xantho incisus
crabs. Two metres away I found a smaller female Xantho incisus. I
found a fourth and larger male Xantho incisus crab under another cobble
one metre away.

I found two large pre-nuptial butterfish, Pholis gunnellus, wrapped
around each other under a cobble on muddy sand and shell fragments. One
individual had 12 conspicuous white ringed black spots along the dorsal
surface, with yellow/olive coloured pectoral fins and edged dorsal fin.
The body was brown with white blotches. The other individual had fewer
spots along the dorsal surface (4?) and had finer white speckling on a
redder body. 

There were two juvenile spaghetti-thin 4 cm long butterfish under an
adjacent cobble. 

I found a tompot blenny, Parablennius gattorugine, in the same area and
three worm pipefish, Nerophis lumbriciformis. Two of the worm pipefish
were males carrying fertilised eggs on their abdomen and the other was
an ovigerous female. Rock gobies, Gobius paganellus were abundant.
Under some cobbles there were pairs of them.

Pilumnus hirtellus, Galathea squamifera, Athanas nitescens, and
Porcellana platycheles were abundant under cobbles. I saw also Cancer
pagurus, Necora puber, and Pisidia longicornis.

In a gully with many crevices I saw six groups of Nucella lapillus egg
capsules. One crevice contained three individual dog whelks with egg
capsules. One of the dog whelks was extended out of her shell and I
presume in the process of producing an egg capsule.

I find two gelatinous scale worms, Alentia gelatinosa (length about 4
cm). One of them was in the same gully as one found last year on 11
January 2005.

I saw two contracted Berthella plumula under dry rocks.

Hippolyte varians were abundant in tufts of seaweed (Fucus and reds).
Also captured and released - a juvenile ballan wrasse, Labrus bergylta,
a small headed clingfish, Apletodon dentatus, a two-spotted goby,
Gobiusculus flavescens, and several shanny, Lipophrys pholis.

I saw several daisy anemones, Cereus pedunculatus, and a dahlia anemone,
Urticina felina, which I had not noticed at the present location before.
I have now been monitoring three beadlet anemones, Actina equina, for
two years (it seems longer) but they remain in place.

Just below the Fucus serratus zone I found under a boulder in a shallow
pool 22 stars of the star ascidian Botryllus schlosseri.

A good start to the year lets rock . and pool our resources!

Best Wishes,
Yours sincerely,
Richard
Richard Lord
Guernsey GY1 1BQ

Tel: 01481 700688
Fax: 01481 700686
Email: fishinfo@guernsey.net 
 


 
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