THE TANG OF THE BAHAMIAN SEAS… BLUE TANG, IN FACT


Blue Tang School ©Melinda Riger @ G B Scuba copy

THE TANG OF THE BAHAMIAN SEAS… BLUE TANG, IN FACT 

The Blue Tang Acanthurus coeruleus is a species of Atlantic surgeonfish mostly found on coral reefs. They are known as surgeonfish because they can slice you with their sharp, spiny caudal fins. Adults are blue, ranging from a deep blue or even purplish to much paler blue.fish28Blue Tang ©Melinda Riga @ G B ScubaBlue Tang ©Melinda Riger @ GB Scuba

Surprisingly, as juveniles, Blue Tang are bright yellow.Blue Tang (juv) © Melinda Riger @ Grand Bahama Scuba Blue Tang (juv yellow form) © Melinda Riger @ G B Scuba

As they grow, they become blue, with the tail being the last part to lose the yellow.Blue Tang (Juvenile) ©Melinda Riger@ G B Scuba Blue Tang (juv, changing colour) © Melinda Riger @ G B Scuba

Blue Tang are herbivores, cruising constantly round reefs feeding on algae. They also act as cleaners of other fish species, removing parasites. They themselves may be cleaned by gobies by visiting so-called ‘cleaning stations’. These piscine beauty parlours have a medicinal purpose as well, since cleaning helps to cure minor wounds.

These fish often move around reefs in large schools, as shown in the header image. Apart from having some value as an aquarium fish, they are not generally of use to humans. Their spiny caudal fins can cause a nasty wound. They have an unpleasant smell. Their flesh supposedly contains toxins, and they carrying a risk of the disease CIGUATERA. I can’t even find a recipe for them online – now, that is a bad sign, there are some people who will try anything. I guess best to boil them for an hour or two, drain the water, allow to cool, and throw away the fish.

FUN FACT In the Disney/Pixar film Finding Nemo, the character Dory (voiced by Ellen DeGeneres) is a blue tang.

Blue Tang, Abaco fish22

BLUE TANG: THE MOVIE [RE-RELEASE]

“RECIPE Take one incompetent swimmer who hasn’t snorkelled in, oh, nearly 40 years. Place him over a coral reef for his first time ever. Add a small underwater camera totally alien to him. Immerse for 30 minutes in warm briny water. Lessons have been learnt for next time. Mainly, don’t keep waving the camera about; let the fish move round you rather than vice versa; and most important of all, remember to keep breathing or else…

Here is BLUE TANG: THE MOVIE (music by Adrian Legg), 45 secs of advanced camera-shake with some beautiful fish more or less in shot for most of the time. If you are prone to sea-sickness, do not enlarge the video. If you are allergic to poor photography… well, thanks for visiting.”

Credits: Good pictures, Melinda; bad pictures and execrable movie, not Melinda

LIONFISH: FURTHER RESEARCH INTO THE CARIBBEAN POPULATION EXPLOSION


LIONFISH – MARMITE DENIZENS OF THE OCEAN

A short time ago I posted in some detail about the poisonous LIONFISH. I included material about the rapid increase of this Pacific species in Caribbean and Floridian waters following accidental / deliberate releases in recent years. I also included videos from Grand Bahama scuba-expert FRED RIGER to balance the anti-lionfish orthodoxy, showing that the fish in fact do some good on the reefs. The post provoked a few comments, and had a surprising number of hits. Here is some further research courtesy of the excellent SEA MONSTER which adds a dimension to the debate and concludes with a very good point… Incidentally, in a recent morning snorkelling at Fowl Cay Marine Preserve, Abaco, I did not encounter a single one of these creatures (Mrs RH was unluckily stung by a jellyfish, though…). But I guess the Preserve is well policed against such intrusive species, which are otherwise found in large numbers in the area.

Why are lionfish populations exploding across the Caribbean?

Author: John Bruno on June 6, 2012

Lionfish are an exotic fish now found throughout the Greater Caribbean and eastern Atlantic that have become incredibly abundant on many reefs, especially in the Bahamas and off North Carolina. Lionfish are piscivores (fish that eat other fish) and were introduced from the Indo-Pacific by the aquarium trade in the late 1990s off Florida. Mostly likely, someone got tired of their fish and released them purposefully.

One hypothesis explaining their great success is the absence of natural enemies; predators, parasites and competitors.  This is probably compounded by the fact that few Caribbean reefs have any predators left that could eat them (thanks to overfishing).

Another – and I think much more likely explanation – is because there is so much to eat in the Caribbean! Not because there are more fish, but because it is so much easier to catch them. Unlike fish in the Indo-Pacific, native Caribbean fishes do not appear to recognize lionfish as a potential threat.  So the lionfish gobble them up, grow faster, make more babies, spread to new islands, etc.

Case in point: My lab group was working in Belize last week on the lionfish invasion. One of the things we were doing was collecting the otoliths and gonads from lionfish that we speared on a number of reefs to compare their fitness across the Caribbean (e.g., on reefs with and without native predators, etc).  We also looked at stomach contents and many of them had parrotfishes in their tummies or still in their throats!  The photo above is of the eggs from one lionfish we caught near Glovers Reef Atoll and the partial contents of it’s stomach (a juvenile striped parrotfish)!

Lionfish appear to be little more than machines that convert parrotfishes to baby lionfishes. Which is pretty much the purpose of all animals (consuming others and transforming them into your own genotype and species).  But jeez, couldn’t those aquarium hobbyists have released a herbivore that could be converting macroalgae to fish biomass? That would have been much more useful.

THE NATIONAL PARKS OF ABACO


The National Parks of Abaco

Abaco National Park Created in 1994, it encompasses over 20,500 acres of pine forest / coppice and is the principal habitat for the endangered Bahama Parrot and other important species of Bahamian wildlife. The tract covers a large area of the Great Abaco water table and has significant recreational value for the people of Abaco. 

Black Sound Cay Nature Reserve This two acre mangrove reserve is nestled in the harbour of Abaco’s historic Green Turtle Cay. The reserve was established in 1988 to protect a vital waterfront ecosystem and wildlife.

Pelican Cays Land & Sea Park A 2,100 acre area just north of Cherokee Sound in Great Abaco that contains stunning undersea caves, extensive coral reefs and is noted for its fish, plant and bird life.

Tilloo Cay National Park Acquired by the Trust through private donation, this 11 acre area encompasses a tropical wilderness shoreline of outstanding beauty. Exposed to the Atlantic Ocean, the area is an important sea bird nesting site.

Fowl Cay Land and Sea Park Recently created in 2009, an excellent place for reef snorkelling [I will be posting about this in due course…] 

CLICK LINK for Article (Abaconian March 3 2011): The Two Abaco Sea Parks, Fowl Cay & Pelican Cay (BNT)

(Info mostly courtesy of Bahamas National Trust; Article “The Abaconian”)