Whales and dolphins

 

Original text by Peter Evans (1993). Updated by Paul Harvey (2019).

The Shetland Islands, 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.

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. Killer Whales started to occur more regularly during the 1990s and can now be seen year-round with four or more pods appearing inshore on a regular basis during the summer months. Larger pods, sometimes numbering up to 100 individuals, often attend trawlers as they draw their nets up when fishing further offshore. Humpback Whales have become annual visitors, Risso’s Dolphins are reported regularly and species that typically favour warmer water such as Common and Striped Dolphins are occurring more frequently.

With the increased awareness of cetaceans around Shetland generated by social media, 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, 23 species of whales & dolphins have been recorded in Shetland waters.

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.

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.

Minke Whale (Balaenoptera acutorostrata)

Of all the baleen whales, the Minke Whale is the most frequently observed species in Shetland coastal waters. It is most often seen off north Unst, between the Out Skerries, Fetlar and Whalsay, and off the east side of Yell and Mainland. Most sightings occur between April and October, particularly from July to September. Loose feeding aggregations comprising several individuals are not uncommon while several larger groups numbering over 10 individuals have been recorded in late summer.

Fin Whale (Balaenoptera physalus)

The Fin Whale was the principal catch at the Shetland whaling stations with as many as 372 landed in 1905 and over 4,300 taken in total during the two periods of operations (1903-14 and 1920-29). Most of these were taken off the edge of the continental shelf in the Faroe Channel north of Shetland where small numbers continue to be seen today. They are much rarer inshore, however, and in recent years the only reports have been off Noss on 11th August 1994, off Mid Yell on 15th October 1999, off Fetlar on 6th August 2012, off Foula on 12th August 2013, off Noss, which was confirmed when it stranded, on 14th September 2016, and off the Bard, Bressay, on 6th June 2018. Given the difficulties associated with identifying the large baleens whale some of these records may be best considered as unconfirmed.

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 records in Shetland waters are one off Muckle Skerry, Out Skerries, on the 27th August 1993 and one photographed in Firths Voe on 1st September 2011.

Humpback Whale (Megaptera novaeangliae)

Another species whose population size must already have been small at the start of modern whaling in Shetland waters, 49 Humpbacks were taken between 1903-14, but only two between 1920-29. The first recent record was in 1992 but since then sightings have occurred in all but four years, with annual records since 2008. Most have occurred during the winter months, particularly October through December, with as many as four individuals present in inshore waters simultaneously. One animal photographed in Shetland was a match for an individual photographed in the Caribbean suggesting that the Humpbacks seen in Shetland summer in the north-east Atlantic and winter in the Caribbean.  

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 has been an increase in reports since 1985, perhaps associated with a small increase in sea temperature in Shetland waters, with sightings in 19 years up until 2018. Most of these have been between May and September and on two different occasions an individual remained for several months (September 1993 to January 1994, and May to July 2012).

Common Dolphin
Long-finned Pilot Whale (Globicephala melaena)

This was once considered to be the most common whale in Shetland waters, occurring 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).

Both Killer and Minke Whales are now seen more frequently than this species around Shetland, although one or two pilot whales are still seen most years, and pods of 40 or more have been recorded six times since 2010.

Risso's Dolphin (Grampus griseus)

This species may well be resident in Shetland waters as it is recorded year-round, although most sightings are reported in the summer and autumn. Small calves are often seen among the small pods that occur here suggesting that breeding may take place in Shetland waters. It is now the most commonly encountered dolphin in the islands with Bluemull Sound, Noss/Bressay, Sumburgh Head and Fair isle the best places to encounter it.

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 sometimes confused. It is an annual visitor to Shetland waters seen most frequently in the summer and autumn. Schools of 100 or more have been recorded on a number of occasions with 800 seen off Hillswick on 22nd July 2013 and 500 off Sumburgh Head on 26th June 1995. Occasionally smaller groups enter a voe in Shetland and some animals strand, as occurred for example in Clousta Voe in October 1987 and in Weisdale Voe in August 1929.

White-beaked Dolphin   (Lagenorhynchus albirostris)

Back in the 1970s this species was considered to be the most commonly encountered dolphin in Shetland waters and was frequently encountered in late summer from the M V Good Shepherd plying between Grutness and Fair Isle. It appears to have become much scarcer in since the mid 2000s, with just 13 reports between 2015 and 2018! and has now been replaced by Risso’s Dolphin as the most commonly encountered dolphin in Shetland waters.

White-beaked Dolphin
Killer Whale (Orcinus orca)

This species has become a regular visitor to Shetland waters since the early 1990s and as the number of sightings has increased significantly, is now a familiar site to many island residents. It has been recorded year-round but with the majority of sightings between April and July, and at least four different pods now appear regularly in the islands. The pod size is typically between four and nine animals and these pods are often seen hunting seals very close inshore. Larger congregations (sometimes up to 100) gather at trawlers offshore when nets are hauled in – presumably having learnt that this activity is associated with large numbers of available fish. A very successful photoID project, based on dorsal fin shape and markings, continues around the islands.

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.

Striped Dolphin (Stenella coeruleoalba)

Striped Dolphin has a world-wide distribution in tropical and warm temperate waters (Evans 1991). In Britain, it was regarded as rare, normally being stranded in the south-west of England, but has been stranding further north in recent years. The first record in Shetland was of an animal that was initially alive but stranded itself at Bixter in 1993, after which another 14 animals stranded themselves, or were found dead, up until 2018. One of two animals seen at Dales Voe on 16th April 2013 may have swam back out to sea, while two in the East Voe of Scalloway from 22nd-24th October 2016 presumably left the area. It appears that this species has started to appear around Shetland as the sea temperature has risen.

Bottle-nosed Dolphin (Tursiops truncatus)

Although there have been a number of claims of this species in Shetland waters, the only confirmed record was of a stranded animal in south Yell in March 2017.

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. They were both white adults and could conceivably have been the same individual.

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.

Narwhal (Monodon monoceros)

Evans & Buckley (1899) reported that a young male was driven ashore in the Sound of Weisdale on 27th September 1808. The tooth measured 27 inches long externally.

Pygmy Sperm Whale (Kogia breviceps)

One originally seen in Aith Voe on 14th October 2007 and then at Voe, eventually stranded at Brae on 17th October where it was euthanased and was taken to landfill.

Harbour Porpoise (Phocoena phocoena)

Although still the most common cetacean in Shetland waters, the Harbour Porpoise nevertheless has shown distinct signs of decline since 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 and subsequent sightings information, indicate that although porpoises are widely distributed around Shetland, there are definite areas where concentrations occur. These include Orka Voe and off the Ness of Setter in Yell Sound, the Whalsay area, Mousa Sound, Noss Sound and the West Voe of Sumburgh/Quendale Bay (the last particularly between November and April).

Sperm Whale (Physeter macrocephalus)

Although this is a deep water species it is the most commonly stranded large cetacean around Shetland with around 40 recorded strandings since 1980. There have been four individuals seen close inshore in recent years (1989, 1995, 1999 and 2001) the last of which eventually live-stranded, and a further 10 records of animals a few miles offshore including several groups of males that were photographed: 12 between Fair Isle and Sumburgh on 14th July 1998, 12 south of Noss on 28th June 2005 and 6 off Burland, Trondra, on 29th July 2011.

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.

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 five strandings (in March 1946, the winter of 1982/83, September 1983, June 1984 and July 2017).

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.