The Surrounding Sea - Gower - page 116

OYSTERS
Like the common blue mussel, another bivalve mollusc, the native or flat oyster Ostrea edulis , also has a
typical range of species associated with it. The polychaete worm Polydora ciliata burrows into the shell,
weakening it and increasing the oyster's vulnerability to predation and physical damage, whereas the re-
lated Polydora hoplura causes shell blisters. Boring sponges Cliona spp. may also weaken oyster shells
by boring into them, especially in older specimens
One of the earliest records of the oyster at Mumbles relates that Oystermouth villagers used to eat
them on a regular basis and that children were fed oysters from a very early age as a cheap and easily
obtainable supplement. The oyster beds were worked for their own needs until the early 1800s, when the
skills of the villagers were improving and the size of the settlement was growing. More boats were being
usedandtheircatchwasincreasingaspeoplehadbeguntorecognisethepotentialdemandforoysters.By
1830 the oysters were being sold along the South Wales coastline and were transported as far as Bristol.
Transporting oysters over these distances required temporary storage and the oyster fishermen overcame
the problem by building shallow holding pens called 'perches' in the intertidal shallows where they could
hold a week's catch alive, in natural conditions, until an order could be met. Good examples of these can
still be seen on the beach in front of the Salthouse at Port-Eynon. Each man's perch was safe from theft,
protected by an unwritten agreement among the villagers. The fishing period ran from the beginning of
September until the end of April. The oyster spawning months ran from May until August and the fisher-
menwouldrigidlyadheretothisrestperiod.Asinmostfisheries,however,astradeincreasedlargerboats
wereused,andthesmallrowingboatswerereplacedbylargersailingboatsinthemidnineteenthcentury.
The new boats increased the yield substantially and the industry appeared indestructible. In the 20 years
between 1850 and 1870 Swansea and Gower experienced an oyster boom. The boats in Swansea alone
were bringing in around 4,000 oysters per boat per day and the fishermen were making a lot of money. In
1871 when the trade peaked 10 million oysters were landed, fetching £50,000, and there were 600 men
employed in the trade.
The quality of the oyster, the amount of money being made and the huge increase in demand as the
fame of the shellfish spread began to cause problems. Boats arrived from London, Bristol and Liver-
pool and too many fishermen flooding what had been a very lucrative market began to cause a small, but
steady,decline intheprices.By1886thetradehadreacheditslowestebbwithpriceshittingrockbottom,
to the point where the fishermen were struggling to make a living. By 1890 the few fishermen still oper-
ating were bringing in catches of only 200 oysters. The fishery continued at this level until, in 1920 and
1921, the flagellate protozoan Heximata spp. infected the oyster beds, causing mass deaths. Many popu-
lations did not recover and this effectively ended the industry, although one or two boats persevered until
1930, more as a pastime than for employment. Although the oyster beds still exist they remain depleted.
Recovery of the populations is dependent on larval recruitment since the adults are permanently attached
and incapable of migration. This is sporadic, depending on local environmental conditions and the pres-
ence of suitable substrates, especially adult shells or shell debris. At present it seems that the oyster beds
will never improve significantly.
A recent survey of the two remaining oyster beds in Wales found oysters in many sites in the Milford
HavenwaterwayinPembrokeshireandnoneinSwanseaBay.Despitethisresultthereareoysterspresent,
but they are in low numbers, making them harder to find. Over-fishing, pollution and poor reproduction
has brought about a devastating decline in the population.