Suddenly,
the magnificent basking shark is once again appearing back in UK seas.
The Marine Conservation Society (MCS) has just received the first three
sightings reports for 2007, occurring on 22nd March, in Cardigan Bay,
West Wales; on 24th March, near Douglas on the Isle of Man; and most
recently, on 7th April, near Falmouth in Cornwall. Basking shark
numbers will increase dramatically over the next few months, and there
is every chance you might spot one from a beach, cliff top, boat or
surfboard. The Marine Conservation Society (MCS) is appealing to
everyone to report their sightings of these wonderful and endangered
creatures, the largest wild animal to regularly visit the
UK.
The basking shark (Cetorhinus
maximus) is the second largest fish in the world (after the whale
shark, which occurs only in tropical waters), reaching up to eleven
metres in length and weighing up to seven tonnes. They are easily
identified when feeding, swimming slowly with huge mouths agape to
filter the plankton which blooms at the sea’s surface during the warmer
months. This means they are often seen with their nose, dorsal fin and
tail all protruding above the surface. They are also easily identified
by their large, somewhat floppy, triangular dorsal fin, and five huge
gill slits on each side.
The basking sharks’
surface-feeding behaviour, large size and slow swimming speed makes
them extremely vulnerable to collision with vessels, accidental bycatch
in fishing nets and disturbance. Like most shark species, their life
history makes the population itself extremely vulnerable if at all
depleted by these impacts (they are slow growing, mature late and
produce few young). To make matters worse, we know very little about
the population size, and the basking shark is listed as ‘endangered’ in
the NE Atlantic.
The MCS Basking Shark Watch
project has collected information on public sightings of basking sharks
since 1987, and the database now contains over 10,000 sightings
records. 2006 was a record year, with over 2000 sightings, up from 1296
in 2005, itself a record year. The survey has identified ‘hotspots’ for
sightings, including the West Country (particularly Cornwall), Isle of
Man (IOM) and West Coast of Scotland. Sighting numbers generally peak
in June for the West Country and Channel Islands, July for the Isle Of
Man, and August for Scotland, suggesting a possible migration of sharks
from South to North. Very few sharks are seen between the months of
October and March, which had previously been linked with migration to
deeper waters for ‘hibernation’. However, recent tagging studies have
shown the sharks carry on feeding in deeper waters around the coasts of
France, England, Wales, Ireland, Northern Ireland and Scotland. They
have been recorded travelling significant distances (up to 3,400km) and
feeding at depths in excess of 750m.
Angus
Bloomfield, Biodiversity Projects Officer at MCS, said “Public
sightings records, collected and analysed by MCS, make a vital
contribution to our very limited knowledge of the population
distribution over time and space, enabling us to provide better
management and protection for this magnificent yet vulnerable animal.
This data was pivotal to the successful inclusion of basking sharks in
the Bonn Convention on Migratory Species (CMS) in 2005, which has since
resulted in European countries banning landing and trade in the
species. So please send us your sightings reports – they really do make
a difference!”
Sightings should be reported
online at www.mcsuk.org, by phoning MCS
on 01989 566017, or by filling in freepost report cards, available to
order from MCS. Marine turtle and jellyfish sightings should also be
reported to MCS. Posters promoting the sighting schemes, as well as
ID-guides and summary reports are also available free of charge.
Raising public awareness of basking sharks in our
waters is not without its drawbacks, as the species is now suffering
from its new status as a tourist attraction. Naive but
deliberate disturbance from a curious public is an increasing threat.
MCS has received numerous reports of sharks being surrounded by
speedboats, or approached far too close. Collisions with boats are not
unusual, as a feeding shark will not necessarily take evasive action.
But even without a collision, it is illegal to disturb a basking shark
in this way (under Schedule 5 of the Wildlife and Countryside
Act). Please report such incidents to us, at MCS, and also to
the local police force’s Wildlife Liason Officer (every force has one).
Observe the basking shark Code of Conduct (available from MCS) and use
a WiSe-accredited operator (www.wisescheme.org) for
any organised marine wildlife watching trips.
