Sperm whale

Aquatic scientific names in the news …

Sperm whale

An unfortunate series of Sperm whale strandings occurred over the past weekend with one whale coming ashore at Hunstanton beach, Norfolk, and dying on Friday, a further three coming ashore at Skegness over Saturday night and Sunday morning, and one on Monday at Wainfleet in Lincolnshire, five miles south of Skegness. This comes in the wake of the 12 sperm whales that have washed up on the Dutch island of Texel and the German islands of Wangerooge and Helgoland since 11 January.

Sperm whale

One of the great whales*, the sperm whale is the largest toothed whale and largest toothed predator; adult males can measure up to 24 metres long (average 16 metres) and weigh up to 57,000 kilograms (56 UK tons) with mature males being a third to a half longer and three times as massive as females.
Sperm whales have a global distribution but show a preference for ice free waters over 1000 metres in depth. Distribution depends upon season and sexual/social status, however they are most likely to be found in waters inhabited by squid – at least 1,000 metres deep and with cold-water upwellings. They can be seen off the north west coasts of Ireland and Scotland.
Sperm whales can dive as deep as 3,000 metres in dives lasting more than an hour. They feed mainly on squid (including colossal squids and giant squids), octopuses and deepwater fishes, but may also prey on sharks and skates; much of what is known about deep sea squid has been learned from specimens found in the stomachs of sperm whales.

Physeter macrocephalus  Linnaeus, 1758, the Sperm whale or Cachalot.

Etymology

Physeter – Greek, physhthr (φυσητηρ), blowpipe or tube, blow-hole or spiracle of whales, a kind of whale.
macrocephalus – Greek, macro-, makros (μακρος), long, large; -cephalus, kefalos (κεφαλος), head; makrokephalos (μακροκεφαλος), long-headed. Loosely speaking long-headed or big-headed.

The sperm whale’s very large head represents one-quarter to one-third of the animal’s overall length.

* Surprisingly there does not seem to be a definitive meaning of the term ‘Great whale’.  At best the International Whaling Commission publishes a table listing the 13 great whales, 12 baleen whales plus the Sperm whale, which suggests that criteria for inclusion is a minimum average length of 10 metres.

Great white shark

Aquatic scientific names in the news …

Great white shark

A Great white shark estimated to be around 7m in length was spotted about 200m offshore at Marino Rocks, near Adelaide,  Australia on Sunday 17th Jan. Local newspaper, The Advertiser, reported that a Westpac Lifesaver Rescue helicopter tried to herd the shark out to sea where it made its way into deeper water and that it had not been seen again.

The size of this fish puts it on a par with the fictional shark from the Jaws movies and, if accurate, makes it one of the largest Great whites to have been photographed; the average length of a mature specimen is likely to be around 4 – 5.2m with females being larger than males, the maximum total length for this species is subject to speculation and is often grossly exaggerated but the largest reliable record is 6.4m.

Great whiteImage: Shark Alerts SA (click to enlarge)

Shark Alerts South Australia, an organisation that reports shark sightings in South Australia for swimmers, surfers and other coastal water users, confirmed the estimated size using their six-metre jet boat to provide a comparison finding the shark to be larger.

Carcharodon carcharias (Linnaeus, 1758), the Great white shark or White pointer

Etymology.

Carcharodon – Greek, Carchar-, carcharos (καρχαρος), saw-like, jagged; -odon (οδον), odous (οδους), tooth; καρχαροδους, with saw-like teeth.
carcharias (καρχαριας) – Greek, shark, so called from its saw-like teeth.

Linnaeus’s original name for the species before it was moved to the more recent genus was Squalus carcharia (Squalus – Latin, a kind of sea-fish (classical); shark (scientific Latin)) – loosely speaking, shark with saw-like teeth.

In common with a number of other carnivorous shark species, those preying on other sharks, cetaceans (dolphins, porpoises, whales), and pinnipeds (seals and sea-lions) they have a combination of pointed lower teeth with broad triangular serrated upper teeth. The lower teeth allow for the prey to be gripped whilst the upper teeth with their serrated edges cut it into smaller easily swallowed pieces.

Ragfish

Aquatic scientific names in the news …

Ragfish

A an adult female Ragfish measuring around 1.6 metres in length was found on the 7th of January washed ashore near the dock in Gustavus in Southeast Alaska (Alaska Dispatch News 7th Jan.).

Ragfish2Ragfish1

         Images: Glacier Bay National Park and Preserve/Facebook

A seldom seen deepwater fish whose life history is poorly documented, they are a North Pacific species with a distribution ranging from Southeastern Alaska to Japan. There is a difference in both morphology and habitat between juveniles and adults; as they grow they lose their pelvic fins and both the dorsal and anal fins reduce, at one time the different life stages were considered to be two separate species; adults occur near bottom usually at depths from 18 to 732 m (1420 m max. recorded) while juveniles can be found in shallow water or offshore near the surface.

RagfishPlate illustrating supposed species showing difference in morphology
(click to enlarge)

Icosteus aenigmaticus Lockington, 1880, the Ragfish

Etymology.

Icosteus – Greek, Ic-, eikw (εικω), yield, give way; –osteus (οστεον), bone. Loosely speaking – yielding bones.
aenigmaticus – Latin, like an enigma, obscure, enigmatic.

From the original description where the derivation of the common name can be seen:

Etymology: εικω, to yield; οστεον, bone.

Vertebrae numerous; vertebral column highly flexible and soft.
Cranial bones tolerably firm, those of the face and opercles, &c., highly, flexible.
Entire body characterized by a lack of firmness, as it can be doubled up as readily as a piece of soft, thick rag.

Lockington, W. N. 1880 Description of a new genus and some new species of California fishes (Icosteus aenigmaticus and Osmerus attenuatus). Proceedings of the United States National Museum v. 3

Ocean sunfish

Aquatic scientific names in the news …

An Ocean sunfish was found on New Year’s Day 2016 washed up on Whitstable beach (Canterbury Times 4th Jan). A subtropical species with a global distribution, they are by no means rare in British waters but are most often encountered around the southern and western coasts of the British Isles during the summer months.

beached sunfishPhoto Gunther Clasen

At a reported length of 80cm it would seem to be a young specimen given that the average size of an adult Mola mola is 1.8 m from the tip of the snout to the end of the tail fin. Famously the heaviest of all the bony fishes with an average weight of around 1 tonne and a maximum recorded weight of around 2.3 tonnes.

Mola mola (Linnaeus, 1758), the Ocean sunfish

Etymology.

Mola – Latin, mill, millstone; grinders, molar-teeth. Alluding to the fact that the fish is similar in shape to a millstone (G. Rondelet De Piscibus Marinis1554).

This scientific name is an example of a tautonym, that is where both the genus and species name are the same; permissible for zoological nomenclature but not allowable under the rules governing botanical names. The reason for this double naming is not clear, in keeping with the etymology of the word mola it may be a reference to its thick rough skin or possibly to its dentition with its teeth fused to form a parrot-like beak.

Giant squid

Aquatic scientific names in the news …

A giant squid surfaced in Toyama Bay harbour (300km west of Tokyo) on Christmas eve, 2015. A species that is rarely observed at the surface, this animal was a juvenile of around three and half metres in length, most likely in poor health and unlikely to survive.

Video by Takayoshi Kojima

The giant squid is the second-largest mollusc only exceeded in size by the colossal squid. Poorly documented in comparison to their smaller relatives they are are a widespread species, although rare in tropical and polar latitudes, with a vertical distribution of perhaps between 300 – 1000m, largely based on data from trawled specimens and sperm whale diving behaviour.

Known since ancient times (mentioned by Aristotle) mainly from mariner’s tales and the occasional beachings it wasn’t until 2004 that a well preserved specimen was available for study and, around the same time, the first images of live specimens were captured.

It has been suggested that there may be as many as eight species of giant squid but based on the latest DNA evidence it seems likely that there is only a single species –
Architeuthis dux Steenstrup, 1857.

Etymology.

Architeuthis – Greek, Archi-, arxi- (αρχι), chief, principal, first in authority or order (post-classical); -teuthis (τευθις), squid, cuttlefish. Loosely speaking – first squid over all other squid.
dux – Latin, commander, ruler, leader, chief, head.