Whales and Dolphins
in Shetland Waters
Peter Evans
The Shetland isles, lying close to the edge of the European continental
shelf and encircled by the waters of the North Atlantic, are amongst the
richest areas for whales and dolphins (cetaceans) in the entire British
Isles. Most of the larger whales in the region normally inhabit deep
oceanic waters north and west of the shelf. However, since the edge of the
shelf is only a short distance away from the northern shores of Unst it is
not surprising that individuals stray into Shetland coastal waters. This
was capitalised upon in the past centuries by Shetlanders who would drive
ashore the normally pelagic Pilot Whales (known locally as Caain' Whales)
just as the Faroese islanders do to this day.
Photo above: Humpback Whale off Sumburgh Head in 1995 - Lorne Gill /
Scottish Natural Heritage
In 1903, two whaling
stations, operated by Norwegian whaling companies, started in Shetland at
Ronas Voe on northwest Mainland (Thompson 1928). The Shetland Whaling
Company began whaling in April 1903 with a single whale catcher, the Frithjof. The Norrona Company started in June with the catcher
Norrona,
They both operated until September and each boat caught just over 60 whales In the following year, two more stations commenced operations, the
Norwegian Alexandra Company from a station in Colla Firth, Yell Sound,
using one boat in the first year and two boats in each subsequent year,
and the Olna Whaling Company, owned by Christian Salveson & Company,
opened a station in Olna Firth on the west Mainland coast. Four boats were
used in most seasons (five in 1906 & 1907).
All
four stations operated in each year from 1904 to 1914 when whaling was
suspended in British waters for the war years by order of the Admiralty.
The whaling season generally spanned April to September, and the grounds
extended in an arc northwards from west to east of the islands and as far
as 150 nautical miles from the stations. Between 1903 and 1914, a total of
around 4,900 whales were caught. Two-thirds of these were Fin Whales, 30%
were Sei Whales, and the rest of the catch comprised small numbers of
Blue, Humpback, Right, Sperm and Northern Bottlenose Whales. The whale
populations in the region clearly were unable to support such exploitation
and catches in post-war years, 1920-29, numbered around 1,900 whales. Fin
Whales, followed by Sei Whales, continued to be the main species caught
whilst only two Humpbacks and no Right Whales were taken. These last two
species remain rare in Shetland, indeed British waters and populations of
the other large whales are also remnants of their former size.
Besides direct exploitation of whales, humans have probably affected
Shetland cetacean populations by competing for the same food resources.
Major changes in fish stocks have occurred this century, particularly with
respect to North Sea herring whose stocks crashed by the mid-1960's. Most
recently, concern has been expressed over possible effects of the rise in
the industrial fisheries for sprat and sandeel, both of which have shown a
decline in the spawning stock, although other oceanographic changes may
also play a part. In addition, changes in the population sizes of small
cetaceans are difficult to determine since their presence in coastal
waters is usually ephemeral and unpredictable. The inshore harbour
porpoise is the only species which can consistently be seen around the
coasts of Shetland (although this species in fact does appear to have
declined in our waters during recent years, and one possible reason for
this is changes to its food supply), with records of other species
irregular although increasing in frequency. Notable increases in records
during recent years have included Killer Whales with a long-staying pod at
Cat Firth in December 1992 giving many people the chance to view these
animals at close range. In addition, at least one humpback whale has
frequented the area around Sumburgh Head during the last few summers,
often giving spectacular views as it swims close inshore; and large pods
of up to 100 dolphins have been seen regularly during the summer months at
many localities around the isles.
With
the increased awareness of cetaceans around Shetland generated by the
formation of the Shetland Sea Mammal Group the number of sightings of
these animals in Shetland waters continues to increase - hopefully it will
continue to do so for many years to come. To date, 22 species of whales &
dolphins have been recorded in Shetland waters, they are as follows:
Northern Right Whale Eubalaena glacialis
Between 1903 and 1914, a total of six Right Whales were taken in Shetland
whaling operations, all close to the shelf edge north of Shetland.
However, since then, there have been no sightings or strandings of this
species in the region.
Humpback Whale
Megaptera novaeangliae
Another species whose population size must already have been small at the
start of modern whaling in Shetland water, 49 Humpbacks were taken between
1903-14, but only two between 1920-29. Since then, there have been a few
records, in June 1992, May 1993, September 1993, and throughout the summers
of 1994-98. Together with a recent handful of
records elsewhere in Western Britain we may be seeing the first signs of
recovery of this species in British waters.
Photos - (left)
Humpback Whales off Sumburgh Head in 1996 - Hugh Harrop, (right) Humpback
Whale breaching 3 miles east of of Sumburgh Head in 1995 - Paul Harvey.
Fin
Whale Balaenoptera physalus
This
is probably the most common large whale in Shetland waters, and between
1903-14 and 1920-29, over 4,300 Fin Whales were taken, particularly off
the edge of the continental shelf in the Faeroe Channel north of Shetland,
Small numbers continue to be seen in this region during pelagic cruises,
but the species is scarcely ever recorded in Shetland coastal waters.
Catches took place between April and October, mainly from May to August,
with little indication for any latitudinal migration. The only recent
record was off Noss on the 11th August 1994.
Blue
Whale Balaenoptera musculus
At
least 85 Blue Whales were taken by the Shetland Whaling industry between
1903-14 and 1920-29, but as with the Humpback and Northern Right Whales,
populations of this species almost certainly had been over exploited by
1930, Since then, there have been no sightings or strandings in Shetland
waters.
Sei
Whale Balaenoptera borealis
The
second most commonly recorded large whale in Shetland waters, the Sei Whale was hunted extensively in the early years of this century, with over
1,800 taken between 1903-14 and 1920-29, Catches were predominantly from
deep waters in the Faeroe Channel along the edge of the continental shelf.
It is clear that the population in the region was quickly depleted. Up to
1914, annual catches per boat averaged 15.5, but after the respite caused
by the war, within one year of activities numbers had declined to average
annual catches of 5.0 Sei Whales per boat. The whale fishery started in
April and continued through to October. However, very few Sei Whales were
caught in April or September-October, with by far the most occurring in
June. As with the Fin Whale, once the species entered the region in
April/May, it remained there through the summer. The only recent record in
Shetland waters was one off Muckle Skerry, Out Skerries, on the 27th August
1993.
Minke
Whale Balaenoptera acutorostrata
Of
all the baleen whales, the Minke Whale is the most frequently observed
species in Shetland coastal waters. It may be seen close to many headlands
and small islands, mainly on the east side of Shetland, although there
have also been several records from Fair Isle. Most sightings occur
between April and October, particularly July to September.
Photo: Minke Whale
stranded at Levenwick in 1997 - Paul Harvey
Sperm
Whale Physeter macrocephalus
Although a deep-water species, the Sperm Whale has been recorded fairly
regularly in Shetland waters, presumably because of its proximity to the
Faroe Channel and Norwegian Trench. No strong seasonal pattern of
occurrence is evident with sightings/strandings in most months, although
unlike other large whales, numbers have been reported through the winter
months. Most records are of adult males or immatures.
Photos: Sperm
Whale in Weisdale Voe 1999 - Hugh Harrop
Narwhal Monodon monoceros
The
Narwhal is also an arctic species which occurs in British waters only as a
vagrant. The only Shetland record is that of one 'driven ashore' at
Weisdale after being observed entangled amongst rocks in September 1808.
It subsequently died.
Northern Bottlenose Whale Hyperoodon ampullatus
Another deep-water species, the Northern Bottlenose Whale has been subject
to intensive exploitation in the Northeast Atlantic by a modern small
whale fishery operating mainly west and north of Norway though some were
also caught in the region of Shetland and the Faroe Islands. At the end
of the last century, the species was described as 'very common' by Evans
and Buckley (1899), animals being exclusively females or young males,
Between 1903-28, 25 bottlenose whales were taken by the Shetland whaling
vessels, mainly around North Rona and the north of Shetland. However,
whereas an average of 0.24 whales were caught per catcher boat per year
between 1903-14, in the period 1920-29 an average of only 0.07 whales per
catcher boat per year were taken, suggesting that the population was
already well in decline. Similarly, marked reductions in catches occurred
elsewhere in the Northeast Atlantic in the first half of this century, and
now the species appears to be relatively scarce. Since 1913, there have
been only four strandings (in March 1946, the winter of 1982/83, September
1983, and June 1984).
Cuvier's Beaked Whale Ziphius cavirostris
In
the British Isles, the Cuvier's Beaked Whale is most frequently recorded
from the Outer Hebrides and west of Ireland, suggesting a generally
pelagic Atlantic distribution. There are only four records of the species
from Shetland: one was found stranded in August 1932 another was found in
a geo on the east side of Fair Isle in late February/early March 1949, one
stranded near Sandwick in April 1983, and one was found decomposed at Woodwick, along the west side of Unst in May 1993.
Sowerby's Beaked Whale Mesoplodon bidens
This
species appears to have its distribution centred upon the deep waters of
the Norwegian Basin and the adjacent Faeroe-Shetland Channel. Most
strandings in the British Isles come from northern North Sea coasts. In
Shetland. there have been seven strandings since 1913; in July 1923,
November 1948, December 1949, August 1984, May 1987, January 1989 and
December 1994. Like most beaked whales, the species is scarcely ever
sighted at the surface and indeed there have been no positive sightings in
Shetland waters.
Harbour Porpoise Phocoena phocoena
The
commonest of all cetaceans in Shetland waters, the Harbour Porpoise
nevertheless has shown distinct signs of decline during the 1980's. During
1982 and 1983, the entire coastline of Shetland was regularly covered by
Pete Ewins as part of an inshore survey for Black Guillemots. During 1990,
Lucy Gilbert and Peter Evans conducted fifty further land based watches
(each of 100 minutes duration). Both sets of results indicate that
although porpoises are widely distributed around Shetland, there are
definite areas where concentrations occur. These include East Yell Sound,
the Whalsay area, Mousa area, and Quendale Bay (the last particularly
between November and April). On the other hand, much of the west coast of
Shetland appears to have comparatively few porpoises, the only exceptions
being in the vicinity of Scalloway and West Burra Isle.
Common Dolphin Delphinus delphis
The
Common Dolphin has a predominantly warm temperate distribution in the
North Atlantic, so that in the British Isles, it is seen most frequently
off-shore from Southwest Britain. Nevertheless, particularly when there is
a strong flow of the relatively warm Gulf Stream, the species may be seen
in north Scottish waters. There are seven documented strandings of this
species in Shetland this century, February 1936, June 1966, May 1985,
December 1985, August 1986, May 1989 and March 1997. Other than these, a
common dolphin was captured at Urafirth in 1985. Since the UK Mammal
Society's sighting scheme was initiated in 1973, there have been several
sightings of Common Dolphins in Shetland waters, mainly between June and
September.
Bottle-nosed Dolphin Tursiops truncatus
This species has been
scarcely reported from Shetland (and Orkney). Neither Evans and Buckley
(1899) or Venables and Venables (1955) give any records and there have
been no strandings since the British Museum Stranding Scheme started in
1913. Although there are a number of recent sightings of unidentified
dolphins which may have been this species, there are very few definite
Bottle-nosed Dolphin sightings, all between April and September.
Atlantic White-sided Dolphin Lagenorhynchus acutus
As
indicated by its name, this species has a predominantly Atlantic
distribution, generally occurring further off-shore than its relative, the
white-beaked dolphin with which it is often confused, Occasionally groups
enter a voe in Shetland and some may strand, as occurred for example in
Clousta Voe in October 1987 and in Weisdale Voe in August 1929. Since
1913, at least 25 animals of this species have stranded along the coasts
of Shetland, mainly between July and November. The vicinity of Scalloway
on the west coast appears to be frequently visited by white-sided
dolphins. In July 1926, when at least 30 stranded at Scalloway,
'thousands' were said to be around the boat a mile off-shore. In July
1919, a group of about 100 White-sided Dolphins entered Scalloway harbour
and at least two of these were stranded. In October 1936, 30-40 were seen
over a period of several days between Burra Isle and Scalloway and in
September 1990 about 50 remained in Whiteness Voe for several days. Most
recent sightings also come from the west side of Shetland, although large
groups have been seen off the northeast of Shetland and between Sumburgh
Head and Fair Isle. Most sightings occur between June and November.
White-beaked Dolphin Lagenorhynchus albirostris
Although it is possible that this species has increased in Shetland waters
in recent years, it is likely that in former times it was under-recorded.
Venables and Venables (1955) did not even list the species and instead
referred to the Atlantic White-sided Dolphin as 'the commonest dolphin to
be seen in Shetland waters'. However, observers frequently confuse the
species with White-beaked Dolphins since the latter also have conspicuous
areas of white on their flanks. Our own experience since the late 1970's
is that the white-beaked dolphin is by far the commonest dolphin in
Shetland coastal waters, as exemplified by ferry crossings between
Grutness and Fair Isle and research cruises we have conducted east of
Shetland (Evans 1981, Evans et al. 1986). Sightings occur in most months
of the year, but are most common between May and September. Despite the
high frequency of sightings, there have been only three strandings in
Shetland, in January 1960, February 1986 and March 1996.
Striped
Dolphin Stenella coeruleoalba
The
only records are four strandings. Singles stranded in Bixter Voe on the
14th July 1993, at Muckle Roe on the 1st January 1995, Whal Firth on the
2nd March 1998, and one was washed ashore freshly dead at Spiggie beach on
the 16th November 1999. Striped Dolphin has a world-wide distribution in
tropical and warm temperate waters (Evans 1991). In Britain, it is
regarded as rare, normally being stranded in the south-west of England,
and in recent years in Wales.
Photo: Striped Dolphin stranded at Bixter Voe - Neil Anderson
Killer
Whale Orcinus orca
This species is a
regular visitor to Shetland waters with the number of sightings in recent
years increasing significantly. Most sightings occur between April and
July when pods of up to half a dozen animals may be seen regularly,
although the species has also been observed occasionally during the winter
months November-February when many of the strandings have also taken
place. There have been eleven strandings since 1913; in December 1932,
September 1937, February 1944, March 1965, February 1966, March 1966,
August 1976, December 1980, December 1983, November and December 1994, and
April 1995.
Photo: Killer
Whales at Quendale Bay - Alan Blain
False
Killer Whale Pseudorca crassidens
This
species only occasionally comes onto coastal waters of the British Isles,
being normally a pelagic species living far off-shore. There has been only
one stranding of the species in Shetland, in February 1944, and no
sightings.
Long-finned Pilot Whale Globicephala melaena
This,
the commonest whale in Shetland waters, may be seen in most months of the
year, although it is generally a pelagic species and sightings in coastal
waters are most frequent in the winter months November to March. For
centuries, this species was the object of an opportunistic drive fishery
similar to that which exists to this day in the Faroe Islands. The last
drive organised in Shetland was a kill of 83 whales in Weisdale Voe in
February 1903 (Venables and Venables 1955) although there is a record of
the species being killed at Reawick in 1928. The largest catch on record
was of 1,540 animals in Quendale Bay in September 1845 (Evans and Buckley
1899). Since the British Museum stranding scheme was initiated in 1913
there have been at least 21 stranding events. Included amongst these are
two mass strandings, of 5 (probably more) at Basta Voe in December 1982,
and 32 (+8 successfully returned to the sea) at Ura Firth, Hillswick in
October 1983.
Risso's Dolphin Grampus griseus
This
species is a regular visitor to Shetland, mainly between April and
September. Sightings have been most frequent on the south and east sides
of Shetland, particularly Balta Sound, Yell Sound, Out Skerries and
Whalsay, and between Noss and Sumburgh Head. There have been at least
seven strandings of this species since 1913; in May 1947, February 1982,
May 1987, April 1988, May 1989, September 1989, September 1990, May 1993,
and July 1993. As with other small cetaceans, it is very likely that
strandings of this species are much under-recorded.
Beluga Delphinapterus leucas
There are two confirmed records. During the late afternoon of 4th
September 1996 a single animal fed in the waters between Hoswick, Broonies
Taing, Levenwick and Channerwick in the South Mainland. It was estimated
to measure around 12-14 feet in length. The other record also involved a
single animal - seen feeding in shallow water off Lunda Wick, Unst on the
18th August 1997.
Beluga Whales are distributed across the entire Arctic Ocean and rarely
penetrate temperate waters. There have been less than twelve records of
the species in British waters including an animal reported off Muness,
Unst during the summer of 1976 (Alan Whitfield pers.comm). There have also
been a number of recent sightings from the Danish, German and Dutch coast
suggesting that a small percentage of the Barent's Sea population may move
south and remain in North Sea waters.
Photo - the 1996 Beluga off Hoswick - Hugh Harrop
Nature in Shetland
