Category America South – Pacific – Tropical

The state gem of Hawaii is black coral, but hold on to your hula skirt, because this jewel’s no rock! Black coral actually comes from the skeletons of live animals. Related to jellyfish, black coral is made up of thousands of tiny polyps. The polyps shoot out poison-filled microscopic barbs to harpoon, kill and swallow plankton.

Black coral isn’t black. The name refers to the color of the skeletons, which are built from tough protein. The living colonies are yellow, green and orange. Black corals are colonial cnidarians in the order Antipatharia that are most closely related to gorgonians and stony corals. There are over 200 described species.

They are found throughout the world’s oceans, but are most common in tropical deep water habitats from 30- 80 m depth...

Diadema spp.

Sea urchins are often used as indicator organisms in public aquariums to determine whether the system is functioning properly. These organisms are extremely sensitive to water conditions and are first to show signs of stress, seen when their spines are laid down or are shed.

Warning! Some sea urchins are covered with sharp venom-filled spines that can easily penetrate and break off into the skin – even through a wetsuit. The DAN (Divers Alert Network) website contains useful information on how to handle the unfortunate effects of accidental brushes with these and other poisonous marine organisms. Check out www.diversalertnetwork.org for any information that you need.

Sea urchins (echinoderms) are a group of marine invertebrates that can be found in almost every maj...

The Palinurus genus (frequently transcribed as Panulirus) is represented by numerous species in all of the world’s tropical and sub-tropical seas as well as more temperate waters. It is a predatory, nocturnal animal with a vividly decorated coat. They are often numerous locally; they linger in crevices (with their long antennae sticking out) during the day and hunt small benthic organisms at night, but they also feed on organic detritus whenever they happen across it.

Lobsters have recently suffered a dramatic demographic decline; entire populations have been annihilated by intensive fishing, especially where tourism abounds. Please record all sightings of lobsters, identifying individual species where possible...

Serranidae

When people talk about coral reefs, fishermen tend to shrug their shoulders and complain about snagged lines and torn nets. But when you talk about groupers, they suddenly sit up and pay attention. Groupers are among the economicallymost important fishes of the coral reef, because of their popularity as food. Yetwithout the coral reef there would probably be no groupers. For this reason, groupers are an extremely important indicator species and your record of theirexistence or non-existence during your dive tells us a lot.

The Goliath Grouper (Epinephelus itajara), sometimes called the jewfish, is classified as critically endangered on the IUCN Red List. Found in shallow, inshore waters to depths of 45m, this indicator prefers areas of rock, coral, and mud bottoms...

Identifying sharks in the wild is a great challenge! While scientists can spend weeks examining every detail of a species, divers may encounter a shark for only a few seconds or minutes. Many species look alike and one individual may not be identical to the next. There are, however, relatively few species in any one specific dive site and with some preparation and a little practice it is possible for all of us to recognise the more common and distinctive species. The key to successful shark identification underwater is a process of elimination, based on a mental checklist of the main features to look for in every animal encountered. One feature alone is rarely enough for a positive identification, so gather as much information as you can before drawing firm conclusions.

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