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Share your thoughts, experiences or questions and participate in discussions over our favorite topic : SCUBA diving!

Fish round-up: Meet the boss : the Triggerfish

by Ksso on September 20, 2011

Triggerfishes are members of the Balistidae family which accounts for about 40 species. The Triggerfish is a fairly common species that can be found all over the oceans in tropical and sub-tropical waters (I recently saw a bunch in Thailand). The indo-pacific ocean offers the most diverse set of species.Divers know the triggerfishes well, especially if you've been diving during their nesting seasons since they get really aggressive. I heard numerous reports of divers being chased by them for a long time (and enven during deco stops which can be a hassle) - in those circumstances do not hesitate to kick the triggerfish with your fins.The Triggerfish has a small but strong- jawed mouth...

Fish round-up : the Humpback Whale

by Ksso on August 25, 2011

When it comes to whale-watching, the Humpback whale likes to be the star. This gigantic animal, around 12 to 16m long, is friendly and curious about object entering its environments and can often come for minute drolling around a boat full of excited whale-watchers. The Humpback is totally harmless to humans, set aside its huge raw force (being hit by a whale finn must hurt...). It feeds exclusively on krill and small fish. The species is pretty well scattered around the oceans with about 80 000 specimens migrating up to 25 000 km yearly from the cold northern waters in summer down to tropical waters.It's easy to recognize with unusually long pectoral fins and a knobby head. Since it's...

Sci-fi Nudibranchs

by Ksso on July 26, 2011

I just got my attention drawn towards those two amazing nudibranchs... that just look like aliens from a Dragon Ball anime. (there's something of Frazer in them isn't it ? ). These Glaucus atlanticus (left) and Glaucilla marginata were washed up on Surfers Paradise Beach in Queensland Australia in 2007. The larger one is about 35 mm in length.The normal size of Glaucus atlanticus is between 5 and 8 cm in length. The maximum recorded length is 40 cm. It floats upside down on the surface tension of the ocean. G. atlanticus preys on other larger pelagic organisms: the dangerously venomous Portuguese Man o' War Physalia physalis; the by-the-wind-sailor Velella velella; the blue button Porpita...

Fish round-up: the Lionfish

by Ksso on June 13, 2011

Lionfish (Pterois) are beautful - and dangerous. Originating from the Indo-Pacific Ocean, they have been introduced by mistake in the Atlantic in mid-90s and have become invasive along the East Coast of the US. Lionfishes measure 6.2 to 42.4 cm with typical adults measuring 38 cm and weighing an average of 480 g.While beautiful, his tentacles ar poisonous making it a hazard to fishermen and divers. Pterois venom produced negative inotropic and chronotropic effects when tested in both frog and clam hearts and has a depressing effect on rabbit blood pressure. These results are thought to be due to nitric oxide release. In humans, Pterois venom can cause systemic effects such as vomiting,...

Fish round-up: Flying Gurnard

by Ksso on May 28, 2011

Flying gurnards are fast and sneaky. They camouflage on sandy bottom and the moment they feel they have been spotted they race their way away from you. I remember chasing one in Indonesia, Lombok at Meno Wall, and only managed to snap blurry pics after a few minutes of intense race.The Flying gurnards (Dactylopteridae) are fairly widespread as the GBIF map shows, yet they are fairly tough to spot usually (although apparently you now get a lot of those in Malta. They like to stay pretty deep (the oriental flying gurnard usually inhabits sandy bottoms at around 100m/330ft depth). The pectoral fins are normally held against the body, but when threatened the fins are expanded in to scare...

Fish round-up : the basking shark

by Ksso on May 25, 2011

While I never actually encountered one of those, basking sharks have fascinated me since I started scuba diving and learned about them. Basking sharks are the second largest living fish on earth, just after the whale shark.Wikipedia reports that the largest accurately-measured specimen was trapped in a herring net in the Bay of Fundy, Canada in 1851. Its total length was 12.27 metres (40.3 ft), and it weighed an estimated 19 short tons (17 t). Despite the fact that the beast is huge, it's perfectly harmless to humans : it's a slow mover that feeds by filtering water to catch plankton, small fish and invertebrates, basking in the warmer waters at the surface. The teeth in the basking shark...

Fish round-up : the Doplhinfish

by Ksso on May 20, 2011

Dolphinfishes are fairly big creatures (often over 1m) from the family of ray-finned fish. The family has only one genus, Coryphaena, which contains two species, the "Mahi-Mahi" and "Pompano Dolphinfish". They are unrelated to dolphins as they are no mammals.Mahi-mahi means very strong in Hawaiian. Mahi-Mahis can live up to 4 years, weight up to 18kg (40 lbs) and measure up to 2m and are usually bigger than Pompano Dolphinfishes which are often mistaken with teen Mahi-Mahis.Mahi-mahi can be found in the Caribbean Sea, on the west coast of North and South America, the Pacific coast of Costa Rica, the Gulf of Mexico, the Atlantic coast of Florida, Southeast Asia, Hawaii and many other...

Fish round-up: deep-sea "Tortugas Red" jellyfish

by Ksso on May 16, 2011

As I was researching jellyfishes, I ended up gazing on this "Tortugas red" species. As you may have realized, jellyfishes are usually transparent-ish. They can be bioluminescent, they can diffract the light creating rainbow effects... but a red jellyfish that's something really rare.The Tortugas red is part of the "Ctenophora" phylum (one of the 40 divisions of the animalia kingdom) and populates cold waters all over the globe. It lives in deep water which is probably what got it its strong pigmentation.Unfortunately, not much is know about this species that has not even been properly described. The picture above is one of the few proving its existence and dates back from 1984 in Boreal...

Fish round-up: (deep) Sea Pig

by Ksso on April 22, 2011

After a post on the Sea Cow and another one on the Sea Cucumber , I guess Sea Pig has to be next.The sea pig is a funny invertebrate than can be found at depth over 1000m (3000ft). He gets his chubby look because of his especially unusually large round feet and the pinky skin got him this common name. As you can see on the map below, it's pretty widespread, although due to the insane depth there are few records of his presence.

Sea cow round-up : the Dugong

by Ksso on April 18, 2011

Steve (see Steve's dives on Diveboard) who has been diving tens of times in Egypt's Red Sea told me last Friday about the Dugong, and I got absolutely fascinated by this huge mammal.The Dugong is a cousin of the Manatees and spends most of his time eating seagrass at the bottom of the sea. The Dugong and by extension the members of the Sirenians are more related to the elephants than to other marine mammals.Wikipedia tells us that the word "dugong" derives from the Tagalog term dugong which was in turn adopted from the Malay duyung, both meaning "lady of the sea." Other common local names include "sea cow," "sea pig" and "sea camel."Dugongs are found in warm coastal waters from the...