In lieu of an abstract, here is a brief excerpt of the content:

Marine mammals Large whales Five species of large whales are regularly encountered around the islands, including the SpermWhale, a toothed whale that hunts at depth for large squid, and four similar-looking baleen whales, which sieve the rich waters for fish and crustaceans .The commonest baleen whale is Bryde’sWhale, which occurs throughout the year and frequents shallower coastal waters . Other large whales, including BlueWhale, HumpbackWhale and North Atlantic RightWhale, are sighted very occasionally in deeper waters offshore from both sets of islands .These records are thought to relate to groups of whales migrating through the islands, although the distribution of these species remains poorly known in the area, and some species may yet prove to be more regular visitors . 1 SpermWhale L 11–18m Sperm Whales are present all year round in the seas surrounding Madeira, although are most common in the spring and summer months, from March to September. They are also seen in smaller numbers around the Canaries in spring and summer. These are gregarious whales that often travel in pods of up to 20 animals, spending much time in social interactions, including regular breaching at the surface. They can be slate grey or dark brown above, and the skin is deeply corrugated – like a shrivelled prune. Sperm Whales are easily separated from the other large whales by the absence of a dorsal fin, showing just a small hump instead. They also have a much more massive head (roughly one-third of the animal’s overall length!) and a broader back, although these features are hard to make out when viewed from a distance. Unlike the baleen whales, Sperm Whales normally raise their large triangular tail flukes vertically above the water prior to diving. They also release a highly distinctive blow that is angled forwards and leftwards to the sea surface. Animals often rest at the surface for long periods between dives, blowing infrequently as they do so. VU 1 2 MinkeWhale L 7–10m This smaller baleen whale occurs regularly in small numbers off Madeira from June to August and less regularly around the Canaries in the same months. Although it is generally smaller than the other large whales, size is not always easy to determine at sea. The Minke is another dark grey whale with a long narrow back. However, the tall but small sickleshaped dorsal fin is located only about two-thirds of the way along the back, so Minkes show a much longer tail stock between the dorsal fin and the tail. Upon surfacing, the rather pointed head often breaks the surface revealing a pale lower jaw, and there is a single central ridge along the snout, which forms a distinct bump in front of the blowhole. The blow is small, low and easily missed. Minkes usually occur singly or more rarely in very small groups and typically appear or roll at the surface five to eight times between dives. Cetaceans Sperm Whales prefer deep waters, even if fairly close to land. 140 direction of travel Sperm Whales often raise their tail flukes before a deep dive Large Whales 141 2 1 direction of travel direction of travel 1 Bryde’sWhale L 11–15m This is the common large baleen whale around all of the islands and occurs mostly from April to October, although can be seen in any month. It favours shallower waters than Sei Whale, diving in depths of up to 300m, so is often seen closer inshore and is more likely to be encountered from inter-island ferries and coastal boat trips. Bryde’s Whale can be seen singly or in pairs but at favoured spots can also occur in loose groups of up to 20 animals. It is very similar to Sei Whale but is dark smoky grey above rather than blue-grey and shows three parallel ridges between the blowhole and the start of the snout. The dorsal fin is upright and sickle-shaped, as in Sei Whale, but Bryde’s Whale is much more active at the surface than Sei Whale and can often be watched engaging in social behaviour. The blow of Bryde’s Whale is variable; it can be low and bushy like that of Sei Whale but also tall and column-like, as in Fin Whale. DD 2 SeiWhale L 12–16m A large whale that is easily confused with Bryde’s Whale, although it is much less common, and sightings are more restricted to the May–September period. Sei Whale also tends to...

pdf

Back To Top

This website uses cookies to ensure you get the best experience on our website. Without cookies your experience may not be seamless.