The Caithness side the firth extends from Dunnet Head in the west to Duncansby Head in the east. On the Orkney side it extends from Tor Ness (Hoy) in the west to Old Head (South Ronaldsay) in the east.
In the middle of the Firth are two significant islands, Stroma and Swona, with another small group called the Pentland Skerries in the east.
Dunnet Head is also the most northerly point of mainland Britain. John o’Groats, Mey (site of the Castle of Mey), and many smaller villages are also to be found on the Caithness side of the firth along with the town of Thurso on its western fringe.
(Text adapted courtesy of Wikipedia)
The Pentland Firth and Orkney Waters area has been identified as one with significant renewable energy resources, as well as being of exceptional environmental quality. It is also an important resource to both national and local economies. There is a need to examine how future developments can be taken forward in this area in a manner that avoids conflicts with other users of the seas and which ensures that the marine environment is protected. This will be achieved by the preparation and implementation of regional marine plans. However, the process of developing regional marine plans is still in its early stages and marine spatial planning at a regional level is being piloted in the Pentland Firth and Orkney Waters.
To ensure that progress is made while the marine planning process is concluded, a Marine Spatial Plan (MSP) Framework has been created, which sets out a process for the development of future plans. This work, which will have three stages, is being undertaken by a working group consisting of representatives from Marine Scotland, Orkney Islands Council and Highland Council.
(Text courtesy of the Scottish Government)
Seals can be seen at all times of the year in all parts of the firth. They usually bask on the rocks on the ebb (falling) tide since it saves them having to move as the water rises. Large groups of seals can be seen at the north of Stroma, from the lighthouse round to the north-west part of the island and at the south end in the area of the beacon and to the east between the old jetty and the lighthouse. On Swona they can be seen around the midpoint of the west coast. The common seal come in various colours with spots and have their pups in May, June and July. They are of a similar colour to the adults and can swim from birth, The grey seal, which is more common in this area having one of the largest British populations, also comes in a number of colours and live in colonies giving birth to white pups from October through to January. These pups do not swim at first until they shed their white coat. When giving birth seals can often be seen inland.
Porpoises can be seen all year round in all parts of the firth although they tend to favour shallower water. They grow to about 1.5m and are black with a broad based triangular fin which can be seen as they surface. They have a small, rotund body with a short, blunt head, no beak, and a small, triangular dorsal fin. They are usually seen singly or in small numbers although in the autumn many groups may be seen in Gills Bay. When in groups, they tend to swim in a more random fashion than Dolphins who swim together.
Dolphins are not very common but seen from time to time. Many different types visit the firth and may be seen anywhere at any time. Larger than porpoises, 2-3m depending on the type, black, with the rear edge of the fin curved back at the top unlike the straight edge of the Porpoise. Head has a distinct beak. Often swim alongside the bow of vessels and frolic in the bow waves. Probably more than one usually swimming together in a more synchronised manner, sometimes leaping out of the water.
Killer whales are mostly seen around May to July although may be sighted at any time of the year. Usually swim in a pod of a maximum of from six to twelve individuals led by a matriarchal female. Males can grow up to 9m long and can be about 25% larger than females and juveniles in the pod. They tend to be fairly distinctive due to their size, fin and markings. The male has a very tall, triangular and erect dorsal fin which is sometimes tilted forwards. Juveniles and adult females both have a smaller, sickle-shaped dorsal fin. When surfacing the grey saddle shows up over the black back, behind the dorsal fin. It has a conical-shaped black head, with a distinctive white oval patch above and behind the eye, an indistinct beak, white throat and large paddle-shaped flippers.
Minke whales are quite often seen in June and occasionally through to October but also at other times of the year. Tend to feed in the up-welling water of the tidal races but can be seen elsewhere. Usually seen singly but may be in pairs. Grows to 7-8.5m, black with diagonal white band on flipper and a slender, pointed triangular head. Relatively small dorsal fin curved back at top at rear part of body. Will probably see the long back with small fin to rear breaking the surface although they are known to bow and stern ride the waves of vessels.
Basking shark. Rare but being seen more often around May to August. A fish rather than a marine mammal, it spends most of its time cruising on the surface filter feeding. The dorsal fin can be seen moving steadily through the water with the tip of the tail moving from side to side behind it. Usually seen feeding inshore at high tide around here in the Gills Bay, Stroma, area though may be seen in deeper water. Generally around 8m long, greyish brown to bluish black with pale belly. Seen in northern waters in the summer, southern in winter. Often in groups of three or four.
Turtles. Very rarely seen, however, they are occasionally found caught in fishing nets in this area. The leatherback is the most frequently recorded species in UK waters and probably the only one in this area. Grows to about 2.9m with an elongated black shell spotted with white, which tapers to a blunt spike. Migrates to UK waters from the tropics in the summer to feed on jellyfish. There are four other species less frequently encountered in UK waters where they usually occur as stray juveniles carried by currents from warmer seas.
(Text courtesy of Wikipedia)