Swordfish Found on South Wales Beach
The body of a large fish was found washed up on Barry Island beach in
the Vale of Glamorgan. It was a torpedo-shaped fish over six feet long
with a long snout, a crescent tail and curved back fin. It was
obviously a "billfish", one of the group containing swordfish and
marlins. The Marine Conservation Society were contacted and they in
turn contacted Doug Herdson at the National Marine Aquarium in
Plymouth, who manages the UK Marine Fish Recording Scheme. The records
show that while swordfish are rare, they do turn up from time to time
in the waters around the British Isles; but there have only ever been
three marlins found in the UK.
Photographs of the fish were sent to Plymouth and from these it was
possible to identify it as a Swordfish Xiphias gladius ("Pysgodyn
cleddyf" in Welsh) as expected. The fish has since been taken to the
National Museum Wales where it will enter the national collection. On
arrival, it was carefully examined by Dr Peter Howlett, the Curator of
Lower Vertebrates, who confirmed the identification and found it to be
a young specimen 2.24 metres long and between 60 and 80 kg in weight.
It had been dead only a few days, but it had been scavenged by other
creatures and it was not possible to determine the cause of death.
Swordfish can grow to 4.6 metres (16 ft) and weigh over 600 kg, so
this one was a tiddler in global terms. They are often called a
Broad-billed Swordfish, but there is only one species in the world.
They are found throughout the tropical and temperate waters of the
world but appear to prefer sea temperatures of 18°C to 22°C, migrating
to cooler waters to feed in the summer. These oceanic fish chase
herring and mackerel and are among the fastest fish reaching 56 mph.
This is in part due to their being warm-blooded, which allows not only
their muscles but also their brain and eyes to work more efficiently.
Swordfish stranded in Whales. Courtesy of Colin SmithPopulation down
by 65%
By 1998 the swordfish population of the North Atlantic was thought to
have declined, due to overfishing, to only 35% of its original size.
Once mature a female can produce 30 million eggs each year, giving the
stock the capability of rapid recovery. However the females do not
mature until they reach 70 kg, and the average size now landed is a
mere 40 kg. When the population was first commercially targeted in the
early nineteenth century the average fish landed weighed over 200 kg.
Such a decline is a classic feature of overfishing. Drastic fisheries
control measures are now in force for swordfish in the North West
Atlantic, but is disputed as to how effective these have been and it
is claimed that the stock is still at only half the level of a
sustainable population.
Unfortunately, with stocks at these levels swordfish steak must now be
on the "fish to avoid" list. It is to be hoped that effective
fisheries management can be enforced in both the West and the East
North Atlantic so that we can once again enjoy this delightful fish,
both in the wild and on the plate.
In Europe the swordfish have probably decline even more, but they are
still caught in the Mediterranean and Atlantic. Vessels fishing for
tuna in the Bay of Biscay and to the south and west of Ireland
occasionally catch swordfish and they are sometimes landed at Newlyn,
in Cornwall.
They do occur as far north as Sweden, and there are scattered records
of swordfish around Britain since the first one at Margate in 1841.
There are few Scottish records with only four or five in the twentieth
century. They are probably commonest on the south and west coasts, but
do turn up in the North Sea. Records held by the National Marine
Aquarium show that in 2006 one was photographed near Teignmouth, in
Devon and another seen leaping off Dorset, while a small (26 kg) one
was caught off the Northumberland; while in August 2007 an even
smaller one was caught south of the Lizard.
The first swordfish in Wales was off Newport back in 1905; while in
2003 one was stranded at Rhossili on the Gower, despite efforts to
rescue it, it died an hour later. So the present fish is the third
that Mr Herdson has details of in Wales, the National Marine Aquarium
would welcome any other reports.
Douglas Herdson, Information Officer at the National Marine Aquarium
in Plymouth, said "We have phenomenal life thriving in the seas around
the Britain, some of the richest areas being off the Welsh coast, west
of Scotland and the South West. It is great that fish like the
swordfish and sunfish are being seen along with the turtles, dolphins
and basking sharks. We have wonderful marine biodiversity and must
celebrate and protect it."
The UK Marine Fish Recording Scheme welcomes reports of any unusual
marine or estuarine fish seen around the British Isles; `phone 01752
275216 or email fishreports@national-aquarium.co.uk.
Wildlife Extra: September 2008
