Sunday, June 14, 2015

Yellowhead Jawfish

Scientific name: Opistognathus aurifrons
Scientific classification: Animalia, Chordata, Actinopterygli, Perciformes, Opistognathidae, Opistognathus

These fish are given their name due to the yellow colour to the top of their pearlescent blue body. The Yellowhead Jawfish is found most often in sand or coral rubble where they can create burrows that they will retreat into to avoid predation. These fish make the burrows themselves by removing particles and small pebbles to create their home. They can be wary of divers if approached too quickly, but if you stay a few feet away and remain still they will hover above their burrow. The Yellowhead Jawfish retreats into the burrow tail first when intimidated by divers or predators, this allows them to still see their surroundings so they can feed on planktonic matter and small crustaceans that may be passing by. These fish are forced to continually dig out their burrows and can be seen with mouthfuls of sand as they remove debris from their homes. They are found at depths from 3m to 40m (10-130ft) and can grow to be 10cm (4in.) long. The male Jawfish incubates the eggs in its mouth until they are ready to hatch, this takes 7-10 days. The Spanish name for jaw fishes is 'bocas grandees' which literally translates to 'big mouths'!

Foureye Butterflyfish

Scientific name: Chaetodon capistratus
Scientific classification: Animalia, Chordata, Actinopterygil, Perciformes, Chaetodontidae, Chaetodon

As with many other creatures in the underwater world, the Foureye Butterflyfish is named because of its appearance. The black spot on the tail of this butterflyfish is to intimidate and confuse predators who are unsure of which way the fish is looking. These little fish are very populous on our reefs (they are one of the top ten most common reef fish in the Western Atlantic). We see them on almost every dive as they are happy in depths up to around 18m (60ft), and they are not too small at about 4 inches so everyone can spot them. They are most often seen in pairs.

Lettuce Sea Slug

Scientic name: Elysia crispata
Scientific classification: Animalia, Mollusca, Gastropoda, Plakobranchoidea, Plakobranchidae, Elysia
A marine gastropod mollusk. 

The lettuce sea slug is named because of the folded parapodia (ruffles) on its back that resemble lettuce leaves. They can grow up to 10cm (4in.), but the ones we predominantly see around Grenada are usually 6cm or smaller. The colour of the sea slug can be extremely variable - green, blue or pastel colours cream, brown and yellow. The lettuce sea slug has large pale spots on the side of its mantle (body) and the rhinopores (like antanae) are large in size compared to the size of the lettuce sea slug and are rolled. They are found on rocks and reefs to depth of around 12 metres (40 feet) and are common in Grenada, as well as throughout the Caribbean. 
They feed on algae found in the water, and then incorporate some of the chloroplasts (a subunit of a cell, found in plants, which allows the cell to create its own energy using the sun) from the algae to allow themselves to obtain part of their energy from photosynthesis (solar power). The chloroplasts survive in the lettuce sea slug for a little over a month, however the older chloroplasts are continually replaced by newer ones whilst food is in abundance. This evolutionary adaptation allows the lettuce sea slug a greater chance to survive if it's environment changes drastically and the food web is disturbed.

Sunday, February 1, 2015

An awesome few weeks as always at Aquanauts Grenada

A Happy New Year to you all. I hope everyone has recovered from Christmas and is ready for a fabulous 2015.

We have had some great sights over the last few weeks. 

Our dive site 'Kohani' didn't disappoint when it gave us two beautiful longsnout seahorses, as well as the usual viewings of Spotted Moray Eels, beautiful fish, crabs and lobsters of varying sizes, and gorgeous corals.

One of our deeper wrecks 'Shakem', a inter island cargo vessel that sunk once it started taking on water which reacted with the concrete on board (concrete and water doesn't mix well!), has had 2 resident frogfish on it for the last month. Frogfish are usually found as a mating pair; the female is larger than the male and when the pair is ready to move on to pastures new, the female will carry her mate on her back. Our pair consists of a red female and a green male. They are found near each other but not together. 

One of our most popular dive sites is 'Shark Reef'. It is as close to a guarantee to see sharks as we can give. Most often we will see multiple Nurse Sharks, mainly small ones who like to hang out under ledges, but we also get specimens who are up to 2m in length and free swimming on the reef. We also get to see large king crabs, lobsters, stingrays, turtles and octopus; including the image below which shows an octopus having a little lunch snack on a crab.

Our marine park trips are always busy with divers and snorkellers who love to see the marine life as well as the underwater sculptures at 'Molinere Bay' that Grenada is famous for. There is a new sculpture currently under construction that shall be installed soon, so watch this space for pictures when it is ready to be explored. The divers and snorkellers have been treated to some whitenose pipefish, large rainbow parrot fish, humongous Goliath Grouper and reef octopus.

Some other sights we have had over the past few weeks include a Bluespotted Cornetfish (looks similar to a trumpetfish, but the tail just grows out to a point) on 'Veronica L'; two fabulous night dives on 'Veronica L' where we saw many large king crabs, basket stars and an octopus who showed us his amazing colour changing abilities; 3 Caribbean Reef Squid were spotted on our shallow wreck site '1/4 Wreck'; and a leopard flatworm and small reef Scorpionfish out on our reef at 'Purple Rain'.

So what are you waiting for, book your diving trips with Aquanauts Grenada for 2015 now. And come and see some of the best diving the world has to offer!!!!

Friday, December 5, 2014

King Crabtopus

By Chrispin

Photo by Michael Wittkowski
On the 1st of December, going down with a few other divers on one of our most beautiful reefs called Windmill Shallows, there sits a fairly old wreck to the left of that reef if the currents going down, called the Rum Runner.
As we approached the wreck, we all saw the strangest thing.
It was a king crab and an octopus in a scuffle, but the octopus seemed to be winning as the king crab was defenseless under the strong master lock of the octopus. We all felt sorry for it but were also excited about how this was going to turn out.
We spent like 20 mins looking at them slowly move into the wreck with the scuffle as we were slowly running low on air--obviously we planned on seeing much more than that--so we decided to leave and hop back to the amazing reef and continue the dive.
Clearly, since Sci-Fi exists, At the end we all knew what we thought it was, "The King Crabtopus!"

Friday, January 3, 2014

Manta Rays - a not too common sight in Grenada; nevertheless a frequent visitor to our waters.

Manta rays are large eagle rays belonging to the genus Manta. The larger species, M. birostris, reaches 7 m (23 ft) in width while the smaller, M. alfredi, reaches 5.5 m (18 ft). Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Elasmobranchii (sharks and rays) and are placed in the eagle ray family Myliobatidae.
Both species are listed as Vulnerable by the International Union for Conservation of NatureAnthropogenic threats include pollution, entanglement in fishing nets, and direct harvesting for their gill rakers for use in Chinese medicine. Their slow reproductive rate exacerbates these threats. They are protected in international waters by the Convention on Migratory Species of Wild Animals, but are more vulnerable closer to shore. Areas where mantas congregate are popular with tourists. Only a few aquariums are large enough to house them. In general, these large fish are seldom seen and difficult to study