Category Africa – north west – Atlantic – temperate

Scombridae

This is a family of fast-swimming, wide-ranging pelagic fishes who are primarily swift predators of open seas. They have a number of special adaptations for this lifestyle, including a streamlined body form and recessible dorsal and anal fins. Some species are partly endothermic, maintaining a higher body temperature in the swimming muscles. Scombrids often swim in schools and prey on other fishes. Many species are very important as sport fishes and in commercial harvest.

The northern bluefin tuna (Thunnus thynnus) is an oceanic fish, but seasonally comes close to shore and is able to tolerate a wide range of temperatures. They school by size, sometimes together with albacore, yellowfin, bigeye, skipjack...

Sparidae

Seabream or porgies are members of the Sparidae family of carnivorous bony fishes. Porgies are carnivores of hard-shelled benthic (bottom dwelling) some have male and female gonads simultaneously. Others change gender as they get larger.

The structure of the fins of Porgies is essentially the same as in the family Serranidae of seabasses with which they can be confused. There are important anatomical differences, however, most obvious of which are that the edge of the gill cover does not end with a sharp spine in the porgies but is rounded or at most bluntly angular; and that the maxillary bone (the bone forming the margin of the upper jaw) is sheathed and hidden when the mouth is closed...

Lobsters, like shrimps and crabs, are decapods – literally meaning 10 legs – and can be found in all of the world’s tropical and sub-tropical seas as well as more temperate waters. They are predatory, nocturnal animals 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. As with all crustaceans, the lobster moults or sheds its shell to grow.

Lobsters have recently suffered a dramatic demographic decline; intensive fishing has annihilated entire populations, especially where tourism abounds.

The lobster families that you may encounter are the spiny rock lobsters, Palinuridae...

Octopus vulgaris

Octopuses belong to the class of marine molluscs known as the Cephalopoda, with both the octopus and the squid having evolved into intelligent mobile forms of the class, with a range of complex behaviours. They are the most advanced of all the marine invertebrates, with both long and short-term memory functions and the ability to ‘learn’. Although cephalopods are molluscs, most species have evolved to the point where only a diminished internal shell exists, as for example the cuttlebone of the cuttlefish, or as in the case of the octopus, the shell has been completely lost.

The common octopus (Octopus vulgaris) is found world wide in tropical to temperate waters, from near-shor shallows to as deep as 200m. Most scientists believe that the Octopus vulgaris ...

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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