MAKING A SPLASH: SPERM WHALES & MANATEES IN ABACO WATERS


Sperm Whale, Abaco Bahamas (BMMRO)

MAKING A SPLASH: SPERM WHALES & MANATEES IN ABACO WATERS

After a quiet spell on the cetacean and sirenian front, there is exciting news to report. First, the BMMRO encountered two sperm whales just off Sandy Point.  I don’t know how close to the shore they actually were, but it was very friendly of them to come so near to the BMMRO HQ.Sperm Whale, Sandy Point, Abaco BMMRO3

When whales are sighted from the research vessel, one of the tasks is to collect feces. This job is often undertaken by interns, and is a good way to learn that serious research may well involve unattractive work… They practise with… er… coffee grounds and a net. For more on this important yet unappealing aspect of whale research, CLICK NICE TO SEE FAMILIAR FECES. Another essential part of any sighting is to take fluke photos to enable ID.  Every whale has different and distinctive patterning to the fluke, including general wear and tear. As a photo archive is built up, the researchers are able to recognise a particular whale and cross-reference it with previous sightings.

Sperm Whale, Sandy Point, Abaco BMMRO2Sperm Whale, Sandy Point, Abaco BMMRO1

The third task of a sighting is to record clicks made by an individual whale. This enables an estimate of the whale’s size to be made, and again a sound archive is gradually built up from which comparisons can be made.

Sperm Whale, Sandy Point, Abaco BMMRO4

A NEW MANATEE VISITS MARSH HABOUR

FRIENDS OF THE ENVIRONMENT has just reported the sighting of a new manatee at the head of Marsh Harbour harbour. I’m not aware of any other sightings in the last couple of days, but as they say,  “Please keep your eyes out and drive carefully! Contact Bahamas Marine Mammal Research Organization with any further sighting reports by calling 357-6666. You can also share photos with them on Facebook. Also, please do not feed the manatee. They are able to find their own food and anything else may make them unhealthy”.

This is Abaco’s third recent manatee. First there was GEORGIE, who as far as I know is still comfortably settled in the Cherokee area. Then RANDY arrived earlier this and got to within about a few miles of Georgie… High hopes of a meeting – and ‘friendship, maybe more’ – were dashed when Randy turned round and headed back to Castaway Cay. Let’s hope this newcomer stays around. I wonder what he – or she – will be named? My suggestion is Abby or Abi, which I think is unisex…

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Just as with the whale flukes, the tail of a manatee is an important means of identification. The new manatee’s tail has its own distinctive edge pattern, which will enable its future recognition. Here is an image of Randy’s tail, with its unique notch. 

Randy the Abaco Manatee - tail notch

Credits: BMMRO & FOTE with thanks as ever for use permissions

mantsw~1

NASSAU GROUPER: VULNERABLE, ENDANGERED… & NOW PROTECTED


Nassau Grouper ©Melinda Riger @ GB Scuba copy

NASSAU GROUPER: VULNERABLE, ENDANGERED… & NOW PROTECTED

The Nassau grouper Epinephelus striatus is one of a number of Caribbean grouper species found generally in the Northern Bahamas and specifically in Abaco waters. Others include the Black, Tiger, and Yellowfin groupers, the Red Hind,and the Graysby. The Nassau grouper is special, however, not least because (unlike the others) it is on the IUCN Red List as an Endangered Species and is also a US National Marine Fisheries Service Species of Concern. It is considered the most important of the groupers for commercial fishing in the Caribbean, and the IUCN listing data suggests that a population decline of 60% occurred over the last three generations (27-30 years), a startling rate. The current population size is estimated at >10,000 mature individuals.

Nassau Grouper ©Melinda Riger @ G B Scuba copy 2

The Nassau Grouper is a creature of the coral reefs in the Caribbean and adjacent seas, though it can also be found in deep water. It feeds in the daytime on small fish and small crustaceans such as shrimps, crabs and lobsters. It lurks in caves and recesses in the reef, sucking in the prey that passes unsuspecting by. The coloration of an individual fish may vary considerably with conditions, and it can adapt its colour to its surroundings as camouflage.  

Tiger grouper meets Nassau grouperNassau & Tiger Grouper ©Melinda Riger @ Grand Bahama Scuba  copy

Spawning takes place in December and January as the seawater cools, always at full moon, and always in the same place. In the moonlight, huge numbers of the grouper gather together to mate in a mass spawning aggregation. This may continue for several days. However, the species is slow breeder, which is why overfishing is particularly damaging to the population as the depleted stock cannot readily be replaced.

3846_aquaimages Wiki

CONSERVATION ISSUES

There are other besides factors commercial overfishing that make the Nassau grouper so vulnerable, including fishing during the breeding season; taking undersized fish; pollution and reef decline; habitat loss; and invasive species. The spawning areas are especially vulnerable to exploitation. In the Bahamas, as elsewhere,  the government has now instituted a closed fishing season for the Nassau grouper. Here is the BREEF  flyer, just circulated – and in fact the reason for this post, which reminded me that I had planned to write about this fish! 10382222_10152869346685953_7443797899832698038_o

THREATS

The Bahamas National Trust sums up the multiple threats in this uncompromising way:

Nassau grouper is eaten by barracudas, lizard fish, dolphins, sharks and other large predators of the reef community. But the predators that have the biggest impact on the grouper population are humansPeople are fishing groupers before they can grow to maturity and reproduce. Sex change may also cause a problem. In undisturbed areas there are usually equal numbers of male and females. In heavily fished areas there are often three or more times more females than males. This means many eggs will not be fertilized during spawning. Other threats include, habitat destruction, coral breakage from divers, siltation from construction, runoff from logging and agriculture, dredging, sewage, oil spills and other contaminants that harm coral reefs where Nassau Groupers live.

grouperEpinephelus_striatus_2

There’s an extent to which a country can be judged on its attitude to wildlife from the stamps it chooses to issue. It’s something to do with appreciation and promotion of the country’s natural resources. For example, North Korea rates nil in this respect, with stamps involving scary weaponry, flags, marching and eerily glowing leaders – not a single sparrow to be seen.  By fortunate contrast the Bahamas and its Postal Service score very highly in celebrating the diversity of the wildlife of the islands. The Nassau Grouper was first featured on Bahamas stamps as long ago as 1971, some 25 years before the IUCN Red Listing, and probably before the sharp decline in population numbers had even begun.

bahamas-1971-nassau-grouper-sg-363-fine-used-19448-p

In 2012 the Bahamas Postal Service released ‘a new definitive 16 stamp series’ depicting the marine life of The Bahamas. The Nassau has been promoted from 5c in 1971 to 70c in 2012. That’s inflation for you.

bahamas-marine-life-stamps2

Finally in 2013 BREEF’s 20 years of marine conservation was commemorated with a distinguished and colourful set of 8 stamps, noting in their release: ‘Two of the new stamps feature the Nassau Grouper, a now endangered species that has experienced severe population decline throughout the region… BREEF is well known as an advocate for an annual closed season for the iconic Nassau Grouper during its winter breeding period. The push for the closed season was based on scientific evidence of population collapses throughout the region due to overfishing. BREEF is calling on the government to implement a fixed closed season for the Nassau Grouper in order to protect the species and the fishing industry. The closed season traditionally runs during the spawning season from December 1st until February 28th, to allow the fish to reproduce.  BREEF is calling urgently for the announcement of this year’s Nassau Grouper closed season….’ And so it came to pass… Not only is the Nassau grouper now worth 2 x 65c; it is strictly protected for 3 months during its breeding season. Maybe philately even had a hand in getting somewhere…

BREEF_Comemorative_stamps_PastedGraphic-3

Nassau Grouper (Rick Smit wiki)

Credits: Melinda Riger, Rick Smit, Open Source, BNT, BREEF, Wikimedia, Bahamas Postal Service

ABACO’S FOUR PROTECTED AREAS: THE PROPOSALS


ABACO (CUBAN) PARROT (Caroline Stahala)

ABACO’S FOUR PROTECTED AREAS: THE PROPOSALS

The latest version of the 40TH ANNIVERSARY OF THE BAHAMAS PROPOSAL FOR THE EXPANSION OF THE PROTECTED AREA SYSTEM OF THE COMMONWEALTH OF THE BAHAMAS has been published. It is a joint proposal by the Bahamas Government, The Nature Conservancy and the Bahamas National Trust. The breadth of the scheme is very ambitious, affecting all the principal Bahama Islands. To understand the objectives and scope of the project, you can see the whole 34-page project by clicking BAHAMAS PROPOSED PROTECTED AREAS 2014 It is in pdf format, so you should be able to save it if you wish to.

Many people will be familiar with the proposals as they affect Abaco. However since the latest version appears to be a final draft, I thought it might be helpful to show the 4 proposed areas of protection and conservation in their present form. These are, in summary:

  1. THE ABACO MARLS NATIONAL RESERVE A vast area of nearly 200,000 acres (300 square miles) of mangrove flats, sandbanks, creeks and wetland habitat
  2. EAST ABACO CREEKS NATIONAL PARK 13,000 acres (20 square miles) of wetland habitat that provides a vital wildlife nursery, and includes blue holes, creeks and a significant area for recreational activities (though Pete’s Pub at Little Harbour may be just outside the zone…)
  3. CROSS HARBOUR PROTECTED AREA 14,000 acres (21 square miles) in South West Abaco, a crucial breeding area for a number of species,including bonefish
  4. SOUTH ABACO BLUE HOLES CONSERVATION AREA  A huge 34,000 acre (53 square miles) swathe of South Abaco to the west of the E D Highway, incorporating 4 inland blue holes and important cave systems, and 13 offshore blue holes. This is an area of mainly pine forest on land and low waters at sea, with an anticipated value for eco-tourism

Here are the BNT maps showing the extent of each area. Far more information will be found via the link to the report given above. 

THE ABACO PROPOSALS

Abaco Preserves 1 copy

Abaco Preserves 2 copyjpg Abaco Preserves 3 copyjpg Abaco Preserves 4 copyjpg

Credits: Parrot, (ex-)parrot protector Caroline Stahala; Maps, BNT; acres to sq m conversion, Gizmo!

FLAMINGO TONGUE SNAILS: ALL YOU NEED TO KNOW


Cyphoma_gibbosum Clark Anderson - Aquaimages

FLAMINGO TONGUE SNAILS: ALL YOU NEED TO KNOW

I wrote about FLAMINGO TONGUE SNAILS Cyphoma gibbous more than two years ago. They have not changed noticeably since then but this site has – in scope, available material and audience. So I am revisiting these small marine gastropod molluscs, which are related to cowries. The live animal is brightly coloured and strikingly patterned, but that colour only exists in the ‘live’ parts – the ‘mantle’. The shell itself is usually pale and characterised by  a thick ridge round the middle. These snails live in the tropical waters of the Caribbean and the wider western Atlantic. Whether alive or dead, they are gratifyingly easy to identify.

FLAMINGO TONGUE SNAIL ON A PURPLE ROPE SPONGEFlamingo Tongue on purple rope sponge ©Melinda Riger @ GB Scuba copy

FEEDING ON A CORAL STEM

This snail is snacking on a coral stem, leaving a feeding track behind it. The structural shell ridge is clearly visible beneath the distinctively marked live tissue of these creatures.

Flamingo Tongue LASZLO ILYES Cyphoma_gibbosum_(living)_2

The flamingo tongue feeds by browsing on soft corals. Adult females attach eggs to coral which they have recently fed upon. About 10 days later, the larvae hatch. They eventually settle onto other gorgonian corals such as Sea Fans. Juveniles tend to live on the underside of coral branches, while adults are far more visible and mobile. Where the snail leaves a feeding scar, the corals can regrow the polyps, and therefore the snail’s feeding preference is generally not harmful to the coral.

Flamingo_Tongue_Snail_on_Soft_Coral_LASZLO ILYES

The principal purpose of the mantle of  tissue over the shell is as the creature’s breathing apparatus.  The tissue absorbs oxygen and releases carbon dioxide. As I have seen it described (unkindly?) “it’s basically their lungs, stretched out over their rather boring-looking shell”. 

Flamingo Tongue, Abaco (Char Albury)

This snail species, once common, is becoming rarer. The natural predators include Hogfish, Pufferfish and Spiny Lobsters, though the spotted mantle provides some defence by being rather unpalatable. Gorgonian corals contain natural toxins and instead of secreting these, the snail stores them. This supplements the defence provided by its APOSEMATIC COLORATION, the vivid colour and /or pattern warning sign to predators found in many species.

It comes as little surprise to learn that man is now considered to be the greatest menace to these little  creatures, and the reason for their significant decline in numbers. The threat comes from snorkelers and divers who mistakenly / ignorantly think that the colour of the mantle is the shell of the animal, collect up a whole bunch from the reef, and in due course are left with… “boring-looking shells” (see photos below). Don’t be a collector; be a protector…
Flamingo Tongue, Abaco (Char Albury)

These photos are of flamingo tongue shells from the Delphi Club Collection. Until I read the ‘boring-looking shell’ comment, I believed everyone thought they were rather lovely… I did, anyway. You decide!

Flamingo Tongue Snail Shell, Keith Salvesen AbacoFlamingo Tongue Snail Shell, Keith Salvesen AbacoFlamingo Tongue Snail Shell, Keith Salvesen Abaco

Finally, a couple of videos. The first is rather charmingly titled ‘FLAMINGO TONGUES DOING…. SOMETHING’. Any (printable but amusing) suggestions via the Comment box are welcome. The second punchily summarises this post in 30 seconds. Maybe that’s all that was needed!

Image Credits: Clark Anderson, Melinda Riger, Laszlo Ilyes, Charmaine Albury, RH

Doh! Reading through this after posting I can’t remove from my mind the likeness of Homer Simpson on the snail in Melissa’s photo (2). I had to  check it out and… it’s uncanny!

Homer Simpson Flamingo Tongue copy images

WTF? (WHAT’S THAT FISH?) 2: STRANGE BAHAMAS REEF FISH


Scorpionfish Close-up ©Melinda Riger @GBS copy

WTF? (WHAT’S THAT FISH?) 2: STRANGE BAHAMAS REEF FISH

WTF 1 concerned the REMORA, the upside-down looking fish with the trainer-sole sucker on its head with which it attaches itself to sharks and other large undersea creatures. If you’ve ever seen a picture of a shark with one or more grey passengers hitching a ride, those are these.

Remora ©Melinda Riger @ GB Scuba

WTF 2 features some creatures found in the reef waters of the Bahamas that make you wonder just how and why they are as they are. They look unnecessarily complicated, and the design is somewhat outlandish. See what you think of these…

BURRFISH

Burrfish ©Melinda Riger @ G B Scuba

SLIPPER LOBSTER

Slipper Lobster ©Melinda Riger @ GB Scub.

SCORPIONFISH (& header image) camouflaged against coralScorpionfish camouflaged against coral ©Melinda Riger copy

COWFISH

Cowfish ©Melinda Riger @ GB Scuba   Cowfish 2 ©Melinda Riger @ Grand Bahama Scuba copy

TRUNKFISH

Trunkfish ©Melinda Riger @GBS copy 3

PORCUPINE FISH 

“Watch this…”Porcupine Fish (Virginia Cooper via G B Suba)

“Ta Daaaaaa”porcupine-fish

 AIRPLANEFISH*

Airplane remains ©Melinda Riger @ GB Scuba

*Well, it’s really airplane wreckage. Besides a few other planes and a variety of ships that can be explored underwater, there are also two locomotives in Abaco waters that “fell off” a ship while being transported. Now recreate in your mind the subsequent conversation with an insurance company…

APOLOGIES Header image repeated to sort out FB visuals problem that’s driving me nutsScorpionfish Close-up ©Melinda Riger @GBS copy

Credits: Melinda Riger, Grand Bahama Scuba;Virginia Cooper;  itsnature.org

‘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. 

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)

‘TREAT WITH PATIENCE…’ – NURSE SHARKS IN THE BAHAMAS


Nurse Shark ©Melinda Riger @ GB Scuba

‘TREAT WITH PATIENCE…’ – NURSE SHARKS IN THE BAHAMAS

The scientific name for the nurse shark sounds like something Bilbo Baggins might have said to summon elves to his rescue: Ginglymostoma cirratum. Actually the name is a mix of Greek and Latin and means “curled, hinged mouth” to describe this shark’s somewhat puckered appearance. The origin of the name “nurse shark” is unclear. It may come from the sucking sound they make when hunting for prey in the sand, which vaguely resembles that of a nursing baby. Or it may derive from an archaic word, nusse, meaning cat shark. The most likely theory though is that the name comes from the Old English word for sea-floor shark: hurse.

Shark ©Melinda Riger @ GB Scuba

Nurse sharks are slow-moving bottom-dwellers and are, for the most part, harmless to humans. However, they can be huge—up to 14 feet (4.3 meters)—and have very strong jaws filled with thousands of tiny, serrated teeth, and will bite defensively if stepped on or bothered by divers who assume they’re docile. [There are recorded instances of injuries caused to divers who have tried to pull nurse sharks by the tail. And serve them right, I say. Treat them with patience – and respect!] 

Nurse_shark_with_remoras Duncan Wright (Sabine's Sunbird)

Notice that the nurse shark in the above photo, and in the header image, is being attended by REMORAS. Click the link to find out more about the strange relationship these ‘weird suckers’ have with larger marine creatures.

Nurse Shark ©Melinda Riger @ G B Scuba

They use their strong jaws to crush and eat shellfish and even coral, but prefer to dine on fish, shrimp, and squid. [And also stingrays, apparently. They have been observed resting on the bottom with their bodies supported on their fins, possibly providing a false shelter for crustaceans which they then ambush and eat.] They are gray-brown and have distinctive tail fins that can be up to one-fourth their total length. Unlike most other sharks, nurses are smooth to the touch. 

Nurse Shark ©Melinda Riger @ Grand Bahama Scuba

Nurse sharks are found in the warm, shallow waters of the western Atlantic and eastern Pacific oceans. They are abundant throughout their range and have no special conservation status, although the closeness of their habit to human activities is putting pressure on the species.

map-nurse-shark-160-20135-cb1321035858

Nurse sharks are nocturnal and will often rest on the sea floor during the day in groups of up to 40 sharks, sometimes piled on top of each other.

Shark, Nurse (young) ©Melinda Riger @ GB Scuba

FAST FACTS

  • Type: Fish 
  • Diet:  Carnivore
  • Size: 7.5 to 9.75 ft (2.2 to 3 m)
  • Weight: 200 to 330 lbs (90 to 150 kg)
  • Size relative to a 6-ft (2-m) man:
Illustration: Shark compared with adult manNurse Shark ©Melinda Riger @ G B Scuba copy

Credits: All photos Melinda Riger, Grand Bahama Scuba; range map and text mostly  NATIONAL GEOGRAPHIC  filled out with other pickings