Occasional sightings of fin whales have been reported off the Pembrokeshire coast in recent years, and those who see them are fortunate as they are an endangered species due to heavy whaling activities throughout the 20th century.
Also known as the finback, razorback or common rorqual, they are the second longest animal in the world and the second largest rorqual after the blue whale, often reaching 89-feet and weighing nearly 74 tons. Another attribute of the fin whale is its speed. At around 24mph, with bursts of 29mph, it is capable of outstripping the fastest ocean steamship and has been said to have the slender, hydrodynamic shape of a racing yacht. This has given it the nickname “Greyhound of the Sea.” Brownish grey with a paler underside, the fin whale is distinguishable by its backswept dorsal fine well back on the long curve of its back as it prepares to dive. Ship crews and passengers often see them in the Bay of Biscay, their dorsal fin surfacing seconds after the spout is spotted; a thin, vertical spray which often reaches a height of 20-feet. Fin whales are among the oldest cetaceans, reaching an age of 94 years, some exceptional specimens having been discovered to be between 135 and 140 years old. It is one of the more gregarious of the rorquals, often living in groups of six to 10 and in feeding groups of up to 100. The voices of fin and blue whales are said by experts to be the lowest-frequency sounds made by any other animal, and can be detected hundreds of miles from their source. When US biologists first recorded fin whale sounds they did not realise that these unusually loud, long, pure and regular sounds were coming from whales. At first they investigated the possibility that they were the result of malfunction of equipment, geophysical phenomena or emanating from a Russian system of detecting submarines. But eventually, they found irrefutable evidence that they were indeed the vocalisations of fin whales, and males only as they were evidently linked with the whales’ reproductive displays. They also decided that the slow recovery of the fin whale population from the depredations of whaling activity was possibly due to the increase in ocean noise from shipping and naval activity, particularly sonar, during the 20th century as it was interfering with the reproductive process by impeding communication between males and receptive females. Fin whales can dive to a depth of up to 1,540 feet when feeding, the average feeding dive lasting six minutes but the maximum duration up to 17 minutes. When travelling or resting the dive lasts only a few minutes. Fin whales very rarely leap out of the water or ‘breach.’ They are found in all the world’s major oceans, from polar to tropical, and perhaps surprisingly, their only known predator, apart from man, is their first cousin the killer whales or orcas, which have been recorded hounding and killing them in large packs.