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Echinometra lucunter

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...

Especially Spiny Lobster Palinurus argus

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; intensive fishing has annihilated entire populations, especially where tourism abounds.

Please record all sightings of lobsters, identifying individual species where possible.

However, we would particularly appr...

Serranidae (Epinephelus marginatus E. itajara and Mycteroperca acutirostris)

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 economically most important fishes of the coral reef, because of their popularity as food.

Yet without the coral reef there would probably be no groupers. For this reason, groupers are an extremely important indicator species and your record of their existence or non-existence during your dive tells us a lot. Like all indicators, it is valuable if you can record the particular species you sight. However, recording the total number of groupers is just as important. The species that we
would...

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.

earthdive wants you...

Pagrus pagrus

Known as the Red Porgy or the Common Sea Bream, this indicator is classified ‘Endangered’ on the IUCN (International Union for Conservation of Nature and Natural Resources) Red List of threatened species. Found over rocky, rubble, or sandy bottoms, this indicator feeds on crustaceans, fish and mollusks. It can be found as deep as 250m, but we certainly don’t expect any observations at that depth! The body is pinkish silver with an indistinct yellow spot on each scale on the upper half of the body, these spots giving a yellowish striped effect. There is some yellow marking on the snout and upper lip. The dorsal, caudal and pectoral fins are pink.

Acanthistius brasilianus

A member of the Serranidae family, the Brazilian Sea Bass is related to Groupers and can be found in the Southwest Atlantic: Brazil, Argentina and Uruguay. It is up to 60cm long and is commercially fished. The mouth is large and slightly protractile, with well-developed fleshy upper lips. The lower jaw extends anterior to upper jaw. A brownish colour, with 3-4 dark bands on the lateral side of body, there are small irregular shaped dark spots on the body and dorsal and anal fins. The diet consists mainly of crustaceans (crabs) and moluscs (bivalves and small cephalopods) and smaller bony fish.

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.

Sea urchins are extremely sensitive to water conditions and are first to show signs of stress, seen when their spines are laid down or are shed. Sea urchins (echinoderms) are a group of marine invertebrates that can be found in almost every major marine habitat from the poles to the equator and from the inter-tidal zone to depths of more than 5,000 metres.

There are around 800 extant species and the group has a long and detailed fossil record stretching back many millions of years. All echinoderms have tube-feet and these play a very important role in feeding and respiration. Echinoids move by means of spines and climb and cling on to hard substrata by means of their tubefeet. The spines also offer the primary means of defence.

Sea urchins are herbivores and feed in a variety...

Concholepas concholepas

Gastropoda is the largest and most successful class of mollusks (phylum Mollusca), containing over 35,000 living species and 15,000 fossil forms. The shell of gastropods is of one piece (called univalve) and usually coiled or spiraled as in snails, periwinkles, conches, whelks, limpets, and abalones.  Concholepas concholepas is a gastropod and lives along the coasts of Peru and Chile in South America.

The inhabitants call it ‘loco’ and collect it for eating.

Haliotis spp.

Abalones are slow-growing, herbivorous marine snails. They belong to a large class of molluscs (Gastropoda) with singlestructured shells. There are over 100 species worldwide in the single genus Haliotis, which means ‘sea ear’, a reflection of the flattened shape of the shell. It is no surprise then that it is called ‘Oreille de Mer’ in France. Abalone shells can be oval or rounded, with a row of respiratory pores and large dome towards one end.

The strong, muscular foot generates enough suction to allow the abalone to fix itself firmly to rocky surfaces. They are found from the inter-tidal to the depth limit of marine plants, some 80 -100m, from tropical to cold waters. The related endemic Chilean Abalone or ‘Loco’ (Concholepas concholepas) is from a different gastropod fami...