The Surrounding Sea - Gower - page 124

is evidence that the most common, the thornback ray Raja clavata , has declined in recent decades. The
Welsh Skate and Ray Group and the Shark Trust are therefore collecting information on past and present
catches to improve knowledge of the distribution and population trends of these important fish. Skates
andrayshavecommercial,anglingandconservationvalueandtheSouthWalesSeaFisheriesCommittee,
like some other Sea Fisheries Committees, has set a minimum catch size under a bye-law. Although this
is not the most popular method, it is hoped that the current bye-law will be replaced in due course, either
by a new bye-law or by European legislation covering the twelve-mile (22-kilometre) inshore zone. The
decline of most of these species is being used as a clear example of how the Common Fisheries Policy is
failing, and to promote the urgent need for a change.
The common stingray is still, however, found inshore in reasonable numbers during the summer and
must always be handled with great care, as there are venom sacs connected to spines along the slender
whip-like tail, and a wound inflicted by these spines can be extremely painful. Electric rays Torpedo no-
biliana have also been caught in Carmarthen Bay. These rays have rounded disc-like bodies and smooth
skin and two dorsal fins located on a short, thick tail. The upper surface of the ray is dark greyish-blue to
darkbrownandtheundersideiswhite.Thespecies cangrowupto2metres long.Theelectric raycatches
bottom-living fish in its pectoral fins and produces a powerful electric shock from specialised organs loc-
ated in the pectoral fins, which stuns or kills the fish before it is eaten. As a result it was known locally as
a 'numb fish', and Dillwyn records that:
One of these men (fishermen), who called it a Numb Fish, told me he has known it to lie quite
concealed in the mud, both in the weirs and in the sea, at low water, and that the shock creates a
great surprise when it is accidentally trod on .
Ever the enquiring naturalist, he acquired a 'torpedo' that had been caught alive on the 17 July 1840 and
kept it in a saltwater pool he had in his garden, but it soon died. Other rays common in the area include
the thornback ray, the painted ray R. microocellata and the spotted ray R. montagui . The spotted ray has a
flattened, diamond-shaped body with broad wing-like pectoral fins and a long tail. It is similar in size and
shape to the thornback ray, but the latter has characteristic large spines with button-like bases scattered
over its back.
PELAGIC SPECIES
As the Bristol Channel is funnel-shaped, faces southwest and has strong tidal currents it tends to act as a
trapforspecieswhichmaybebroughttothesouthwesternapproachesbytheGulfStreamandtheprevail-
ingwind,suchasthePortugueseman-o'-war Physalia physalia andtheby-the-wind-sailor Velella velella
(Fig.66).Bothareocean-dwellingspeciesthatareoftenwasheduparoundtheGowercoast.InJuly2003,
for example, numerous specimens of by-the-wind-sailor were stranded along the southern end of Rhos-
sili beach and there was a similar mass stranding, all along the South Wales coast, in September 2004.
Like the Portuguese man-o'-war, by-the-wind-sailor is a pelagic colonial hydroid, a complicated colony,
some elements of which specialise in feeding, some in attack or defence, some in reproduction and some
in movement. The float in this species, which is an oval disc, is deep blue in colour and can be up to 10
centimetres in length. Short tentacles hang down into the water from the float. A thin semicircular fin is
setdiagonallyalongthefloatactingasasail,whichgivestheanimalbothitsscientificname(from velum ,
a sail) and its common name. The colony feeds on pelagic organisms, including young fish, caught by
stingingcellsonitstentacles.Inturntheseaslug Fionapinnata ,violetsnail Janthinajanthina andsunfish
Mola mola prey upon the colony. Dillwyn records that in July 1824 there was a mass stranding of violet