THE ARTICULATE WHALE (1): TELLING A TALE AFTER DEATH


False Killer Whale (Endless Ocean-wiki)

THE ARTICULATE WHALE (1): TELLING A TALE AFTER DEATH

The ‘false killer whale’ Pseudorca crassidens has a somewhat misleading name: first (as implied), it is not a killer whale; second, it’s not actually a whale at all, but a large species of dolphin. However, it does have some killer whale tendencies – attacking and killing smaller marine mammals for example – and perhaps a passing resemblance, so the species has been given something of an upgrade, name-wise.

False Killer Whale (NOAA-wiki)

Although these fine creatures are distributed widely around the globe, the overall numbers are thought to be small, and relatively little is known about them in the wild. They are, of course, used as aquarium exhibits but the knowledge gleaned in captivity cannot provide much of an overview of their oceanic behaviour, which remains relatively unstudied.

False Killer Whale range map - wiki

However, there is one source of valuable data – the scientific study of stranded animals. And as it happens, Abaconians will very soon be able to obtain at least a skeleton knowledge of the FKW, the end-product of a long and complicated research project by the BMMRO in conjunction with Friends of the Environment. Just a quick word of warning before you read further – some images below are not especially pleasant to look at, so be prepared for them… They are illustrative and not intended for close inspection (unless you want).

Exactly a year ago an FKW was reported to have stranded on Duck Cay, off Cherokee Sound. BMMRO were quickly on the scene, and hoping to undertake the usual procedure of a necropsy, in which post-mortem samples are taken for analysis. However the poor creature was in an advancing state of decomposition, so only skin samples and photographs could be taken.

False Killer Whale, Abaco Bahamas (BMMRO)         False Killer Whale, Abaco Bahamas (BMMRO)

Telescoping the intervening months for the sake of brevity, the decision was made to cut up the carcass (note the face-masks) and bury it where it was, so that its integrity would be preserved for later retrieval, cleaning, reconstruction (‘re-articulation’) and exhibition for educational purposes.

False Killer Whale, Abaco Bahamas (BMMRO) False Killer Whale, Abaco Bahamas (BMMRO) False Killer Whale, Abaco Bahamas (BMMRO)

False Killer Whale, Abaco Bahamas (BMMRO)

In December, the remains were exhumed for the next phase of the animal’s decomposition – submersion in cages in the mangroves – before the final cleaning of the bones in readiness for its re-articulation and display.

False Killer Whale bones, Abaco Bahamas (BMMRO)False Killer Whale, Abaco Bahamas (BMMRO)False Killer Whale bones, Abaco Bahamas (BMMRO)

Cleaning the bones has been a meticulous process, leaving the resulting skeleton ready to reconstruct in situ at Friends of the Environment’s Kenyon Research Centre in Marsh Harbour. Adult FKWs can grow up to 6 metres long, so there are a great many bones from large to very small to place correctly – and plenty of teeth (see below). The re-articulation is nearly finished, and it is hoped that the completed skeleton will be on display in the very near future. I am planning to see it in about 2 weeks time, and – this sounds quite strange, I know – I’m very excited about it.

False Killer Whale bones, Abaco Bahamas (BMMRO)False Killer Whale bones, Abaco Bahamas (BMMRO)False Killer Whale tooth & bones, Abaco Bahamas (BMMRO)False Killer Whale skeleton, Abaco Bahamas (BMMRO)

This ambitious year-long project has involved BMMRO, FOTE, BEP (Bahamas Environment Protection Foundation), interns, and volunteers. I am keen to know whether, in the modern way, an affectionate name has been chosen for the skeleton. ‘Duck Cay’ doesn’t provide a very promising start. Well, maybe Donald is in vogue…? 

ARE STRANDINGS FREQUENT – AND WHY REPORT THEM?

Each year there may be half-a-dozen reports of cetacean strandings in Abaco waters, both whales and dolphins. As far as I can make out, the animals are almost invariably dead. If still alive, reporting is clearly urgent to ensure a quick response and to maximise the creature’s chances of survival. If dead, a carcass can provide scientists with valuable data on the biology and health of marine mammals and, in turn, the health of our marine ecosystems. This includes basic information, such as an animal’s age, its size, the types of prey it consumes, and the occurrence of diseases. Necropsies can provide more detailed information to add to the growing knowledge-base of marine mammal populations.

And a project like this one, with its great educational potential, can in effect enable a stranded marine mammal to tell its story even after death.

STRANDING NETWORK HOTLINE NUMBER +1 242 366 4155
(or +1 242 357 6666 / +1 242 577 0655)
False Killer Whale skull, Abaco Bahamas (BMMRO)

Credits: header image, Endless Ocean / wiki; #1 NOAA; all other photos BMMRO or FOTE, with thanks; range map wiki 

‘SPOTTED IN ABACO WATERS’: PANTROPICAL SPOTTED DOLPHINS


 Spotted Dolphins Abaco Bahamas (BMMRO)

‘SPOTTED IN ABACO WATERS’: PANTROPICAL SPOTTED DOLPHINS

The BMMRO has posted several reports of dolphin and whale activity around the coast of Abaco during August, with some outstanding photos to accompany them. I had been going to post rather generally about this until a couple of days ago, when an unusual dolphin species for the region was… er… spotted and some memorable images taken.

Spotted Dolphins Abaco Bahamas (BMMRO)

These are PANTROPICAL SPOTTED DOLPHINS Stenella attenuata, whose range encircles the globe but at a lower latitude than the far more frequently encountered resident  ATLANTIC SPOTTED DOLPHINS Stenella frontalis. Here are comparative range maps. The rarity of the Pantropical species in the Bahamas is indicated in the BMMRO report of a stranding in 2011 – see below.

ATLANTIC SPOTTED DOLPHIN                                                                    PANTROPICAL SPOTTED DOLPHIN

Verbreitungsgebiet des Zügeldelfins Stenella frontalis.PNG                                                Cetacea range map Pantropical Spotted Dolphin.PNG

Spotted Dolphin Abaco, Bahamas (BMMRO) copy 2

Spotted Dolphins Abaco  Bahamas (BMMRO)Spotted Dolphins  Abaco Bahamas (BMMRO) copy

The pantropical image below is from the BBC archive and not taken in the Bahamas. I’ve included it for illustrative purposes due to the close-up underwater view of the dolphin.Pantropical spotted dolphin (BBC)

This wonderful underwater video of pantropicals is by Jake Levenson, shot from a polecam. Although it is 6 minutes long, I highly recommend it for (a) the stunning views of these creatures at very close quarters (b) the excellent audio quality – you can clearly hear the dolphins communicating with ‘sonar’ clicks and squeaks, and (c) the strange sense of peace you may feel when you have watched it. 

[youtube http://youtu.be/-hXTYe58g34]

PANTROPICAL SPOTTED DOLPHIN STRANDING 2011

In May 2011 a dead dolphin was found on the sandbank at Casaurina Point, Abaco. BMMRO’s scientists established that it was a sub-adult male pantropical spotted dolphin with a stomach full of squid beaks, a known prey for the species. A full necropsy was conducted on the animal and samples were taken for scientific testing to determine the cause of death. At the time the BMMRO reported the find in their quarterly Newsletter:

Pantropical spotted dolphins are commonly found in off-shore waters, although they can be found close to Abaco’s coastline due to the close proximity of deep waters. They can occur in large group sizes of up to 100 animals. Adult males and females reach up to 2.6 m (8.5 ft) and 2.4m (7.9 ft) in length, respectively. Since our efforts began in 1991, BMMRO has records of only 28 sightings of pantropical spotted dolphins in The Bahamas (my rubric), although their cousin species, Atlantic spotted dolphin, is a common resident. This is the first recorded stranding of this species in The Bahamas.”

Credits: BMMRO / Diane Claridge; BBC; Jake Leveneson (video); Wiki (range maps)