Fin whale
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetartiodactyla
Infraorder: Cetacea
Parvordine: Misticeti
Famiglia: Balaenopteridae
Genus: Balaenoptera
Species: Balaenoptera physalus (Linnaeus 1758)
Description
The fin whale is the largest cetacean in the Mediterranean Sea and the second largest animal on the planet after the blue whale (Balaenoptera musculus).
It is a Mysticetes, that is, a cetacean equipped with baleen. Baleens are a structure that replaces teeth and allows the animals to filter out tiny plankton organisms, krill. Baleen whales' bodies are tapered and hydrodynamic, their length can reach up to 22 meters, and their weight is about 70 tons; females are slightly larger than males.
During the breathing phase at the surface, the animal exhales long vertical cone-shaped blowholes up to 6-7 meters high; as with all Mysticetes, the fin whale blowhole has two orifices. Coloration is slate gray on the back and white on the belly and with an asymmetry in head pigmentation: the right mandibular region is white, and the left mandibular region is dark. Fin whales perform prolonged apneas varying from 5 to 15 minutes and, when diving, rarely show the caudal fin out of the water.
The fin whale is distributed throughout temperate, pelagic waters, although it is sometimes observed at shallower depths. It feeds on tiny plankton, crustaceans, and small fish.
Mediterranean Conservation Status
New population estimates, made in the last years, have re-evaluated the maximum number of mature individuals in the Mediterranean fin whale subpopulation: from <10,000 to <2,500. As a result of these new data, in 2021 the category on the IUCN Red List was upgraded from Vulnerable to Endangered.
The most significant threats to the species are anthropogenic: collisions and bycatches in fishing gear. Other disturbance factors include disturbance from marine traffic, chemical, and noise pollution.
Listed in
Bern Convention App. II
CMS App. I, App. II
CITES App. I
Barcelona Convention, SPA/BD Protocol, Annex II
EU Habitats Directive: Annex IV
Global status
Vulnerable
Fin whale in the waters of Ischia
The presence of fin whales in the waters of Ischia is inconstant. During 1997-2000, fin whale was the most frequently sighted species in the study area, with 66 sightings in three years. The animals were concentrated in the most coastal part of the Cuma Canyon system, north of the island, where they were observed feeding.
The animals spent more time at the surface around sunset, with probable relation to the vertical nictemeral migrations of the preyed euphasiaceans; on these occasions, they were seen swallowing their prey by emerging with their mouths wide open with ventral thrusts.
Analysis of fecal material revealed the predominance of euphasiaceans of the species Meganictyphanes norvegica, a key species in the pelagic trophic web, the main food of fin whales in the Mediterranean. M. norvegica plays an important role in the feeding of other groups of cetaceans, such as odontocetes, as it is also food for cephalopods and fish, prey for these marine mammals.
In later years, the presence of fin whales in the study area has become rarer.
The most recent distribution of fin whales in the study area shows that the animals are sighted in pelagic and coastal waters.
