‘WELL SPOTTED’ (2): ATLANTIC SPOTTED DOLPHINS IN ABACO


Atlantic Spotted Dolphins in Abaco Waters (BMMRO)

‘WELL SPOTTED’ (2): ATLANTIC SPOTTED DOLPHINS IN ABACO

No sooner have I posted about PANTROPICAL SPOTTED DOLPHINS sighted during the current BMMRO whale research program, than the other Bahamas spotted dolphin species shows up as well. These are the more numerous Atlantic Spotteds Stenella frontalis, more confined in range (as the names suggest) than the Pantropicals. 

Atlantic Spotted Dolphins in Abaco Waters (BMMRO)

The BMMRO caption reads “Atlantic spotted dolphins today! Small social group playing with sargassum – they swam past what looked like a plastic mattress cover – one dolphin whacked it with its tail as it swam by…”

Atlantic Spotted Dolphins in Abaco Waters (BMMRO)

Just because it can…Atlantic Spotted Dolphin leaping in Abaco Waters (BMMRO)

RUBBISHING RUBBISH: A RANT

Behold a large plastic bag, made by humans and dumped by humans into a place that is not theirs to use as a trash repository. It will take some 500 years to break down completely. But when people say that they don’t really mean it will have harmlessly disappeared over that period and become salt water. Far rom it. It will just break down into smaller and smaller pieces, to bite-sized bits for turtle, fish and seabirds who will idiotically mistake them for food (duh!), then to micro-plastic that will become part of the evolving plastic soup that will be ingested by tiny sea creatures and coat the reefs in polyethylene gunk. [End of rant. Ed.]

Atlantic Spotted Dolphins in Abaco Waters - marine trash (BMMRO)

Behold an Atlantic Spotted Dolphin giving the bag a passing whack with its tail. It won’t do anything to help with marine pollution, but is shows a robust disdain for a piece of man-made rubbish that has made it into the creature’s home environment.

Atlantic Spotted Dolphins in Abaco Waters - marine trash (BMMRO)

Below is a short GoPro shoot of a pair of ASDs, that I took from the BMMRO research boat last year. Marvel at the grace and elegance of these beautiful animals as they swim just below the surface (wonder, too, at the incompetence of the cameraperson who, to be fair, was leaning over the side of the RHIB with the camera on a stick…)

All photos BMMRO; video from the Rolling Harbour achives, intemperate rant all my own

‘WELL SPOTTED’: PANTROPICAL SPOTTED DOLPHINS IN ABACO


Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

‘WELL SPOTTED’: PANTROPICAL SPOTTED DOLPHINS IN ABACO

Two species of spotted dolphin are found in Bahamas waters. The most common is the ATLANTIC SPOTTED DOLPHIN Stenella frontalis, a species confined to the Atlantic. Less commonly seen – though with a global range – are Pantropical Spotted Dolphins Stenella attenuata

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

The BMMRO research boat is out whale-spotting right now, and the team is finding a good variety of cetacean species, from dolphins right up to SPERM WHALE mother and calves. A couple of days ago, the pantropicals surfaced and these great shots of them were taken.

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

The two spotted dolphin species are very similar to the untrained eye. Identification is further complicated by the fact that both species start life without spots and go through stages ranging from no spots at all to completely spotted. These stages are sometimes referred to as ‘two-tone, speckled, mottled, and fused’. The pantropicals are relatively small, reaching lengths up to 7 feet and weighing c250 pounds at adulthood. Their beaks are longer and more slender than the familiar but larger bottlenose dolphin. The beak has a white tip, a useful identifier.

Atlantic Spotted and Pantropical Spotted range maps for comparison

The pantropicals favour shallower water by day, and at night they move to deeper water where they can dive down for food such as squid. Although they are IUCN listed as ‘Least Concern’ and their world-wide numbers are estimated to be abundant, they face the usual man-related threats to the species throughout their range, especially in the Pacific region. As we see time after time, complacency can turn to concern in a very short time.

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

THREATS TO THE SPECIES

  • Entanglement in fishing gear – captured as bycatch in the course of commercial fishing
  • Entangled in discarded fishing gear
  • Illegal feeding and harassment – this is a problem in particular locations eg Hawaii
  • Overexposure to and interaction with eager tourists in inshore areas
  • Hunting – these dolphins are prolifically hunted for food in several parts of the world
  • Hunting – they are caught ‘accidentally’ in large numbers in nets set for tuna
  • Persecution in eastern tropical Pacific fisheries, according to WDC
  • Pollution, plastic ingestion etc – basically, mankind’s negligence over 60 years or so
  • General habitat degradation, disturbance and marine noise pollution – mankind again

Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)Pan-tropical Spotted Dolphins, Abaco Bahamas (BMMRO)

Credits: BMMRO for all photos; research credits NOAA; WDC

SPERM WHALES – BMMRO FIELD TRIP, BAHAMAS


Sperm Whales, Bahamas (BMMRO)

SPERM WHALES – BMMRO FIELD TRIP, BAHAMAS

I can never quite get my head around the fact that the waters around Abaco are home to the twin leviathans, sperm whales and humpback whales. And before anyone points it out, I realise they can’t actually be twins: sperms whales (cachelots) are TOOTHED WHALES whereas humpback whales are BALEEN WHALES

Sperm Whales, Bahamas (BMMRO)

During November, the Bahamas Marine Mammal Research Organisation (BMMRO) undertook a rather special field trip. Using sophisticated devices, the scientists first located a group of sperm whales, and then tracked them through the night using the communications between the creatures – ‘vocalisations’ – to follow them. Later analysis of the recordings will have made it possible to identify the individuals through their unique vocal patterns – and so to recognise them again. 

Sperm Whale, Bahamas (BMMRO)

The hydrophonic equipment used is extremely sensitive, and can pick up the sounds made by whales and dolphins over a great distance. The box of tricks looks deceptively modest – I took these photos on a previous trip when we were looking for beaked whales and dolphins. Charlotte Dunn holds the microphone submerged on a cable and underwater sounds are amplified so that the slightest chirrup of a dolphin can be heard by everyone on the vessel. The sounds are recorded and locations carefully logged.

Besides the sperm whales, the BMMRO team also had sightings of spotted dolphins, bottlenose dolphins and beaked whales during the field trip. These bonus sightings will also have been logged for future reference. It all adds to the detailed research data that assists the conservation of the prolific marine mammal life in Bahamian waters.

Atlantic Spotted DolphinsAtlantic Spotted Dolphins, Bahamas (BMMRO)

By the time one of the whales decided to breach, it was some distance away, so I’m afraid I can’t bring you a dramatic close-up from the trip. But just to see this view at all is breathtaking.

All photos BMMRO except the 2 hydrophone ones on the research boat (Keith Salvesen)

DOLPHINS DISPORTING IN THE BAHAMAS


Atlantic Spotted Dolphin, Bahamas (BMMRO)

DOLPHINS DISPORTING IN THE BAHAMAS

‘Disporting’. Not a word I’ve used very often. Or possibly ever. It looks a bit like ‘unsporting’, which is emphatically what dolphins are not. Basically, it just describes what dolphins are doing when you see them on the surface: amusing themselves, frolicking around in the waves, and simply enjoying themselves.Bottlenose Dolphin, Bahamas (BMMRO)

True, they are probably keeping an eye out for food… But when you have a group sociably following alongside the boat your are in, moving in front, dropping behind, diving under, and generally playing around, it’s quite hard to believe that these are completely wild creatures. They seem to be performing just for you, simply because they want to. You don’t even have to throw fish at them to earn this free display.

Atlantic Spotted Dolphin, Bahamas (BMMRO)Atlantic Spotted Dolphin, Bahamas (BMMRO) Atlantic Spotted Dolphin, Bahamas (BMMRO)

As is well-known, the BAHAMAS MARINE MAMMAL RESEARCH ORGANISATION (BMMRO) is the custodian for the welfare of these beautiful creatures for the entire Bahamas. However, being based on Abaco and carrying out the majority of the research from the HQ at Sandy Point means that many of the great images that get taken are from Abaco waters. Indeed some are taken within swimming distance (not mine) of the shore.  Bottlenose Dolphin, Bahamas (BMMRO)Bottlenose Dolphin, Bahamas (BMMRO)Bottlenose Dolphin, Bahamas (BMMRO)Bottlenose Dolphin, Bahamas (BMMRO)

The photographs featured here were taken during the last few weeks. Some are of the familiar bottlenose dolphins. The others – with speckled undersides clearly visible in the header image & below – are of Atlantic spotted dolphins. There’s even one of my own taken from the research vessel. Atlantic Spotted Dolphin, Abaco Bahamas (Keith Salvesen)Atlantic Spotted Dolphin, Bahamas (BMMRO)

For the researchers, the most important part of an individual dolphin is its dorsal fin. Unique patterns of cuts and scars mean that each dolphin sighted can be logged and their profiles built up. Some have been found in the same area for many years. They are not usually given jocular names – ‘Davy Jones’, ‘Finny Phil’ or whatever. The first time we went out on the research vessel we were slightly surprised by the practical, scientific calls during a sighting of a dolphin group: “there’s B4 again” and “over there – D5 is back”. All said fondly however – many of the dolphins are old friends.

This dolphin has a notable notch on the dorsal fin with a nick below, & a scar line – with a prominent white scar on the lower front edge Bottlenose Dolphin, Bahamas - Dorsal Fin Damage (BMMRO)

Notice how these 3 dolphins all have quite different fin profiles.  The nearest one’s fin looks unblemished, but has a paler tip. Powerful binoculars and a serious camera can pick out small  differences at a distance that the eye could notBottlenose Dolphin, Bahamas - Dorsal Fin Damage (BMMRO)

Coming soon: Manatees & Man in the Bahamas

All photos (bar one by me) BMMRO, with thanks to Diane & Charlotte, and a tip of the hat to the current interns involved in the research projects (Hi, UK Thomas!)

ATLANTIC SPOTTED DOLPHINS OFF ROCKY POINT, ABACO


Atlantic Spotted Dolphins off Rocky Point, Abaco

This pair was in a group of 8 Atlantic Spotted Dolphins that we encountered yesterday during a day’s expedition on the Bahamas Marine Mammal Research Organisation (BMMRO) research boat. We spent nearly an hour with them, and there will be a longer post about these magnificent creatures in due course. But right now, I’m still in single image posting mode while “on-island”…

Photo: Keith Salvesen / BMMRO

‘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)