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Didemnum sp.

Tunicates are a group of marine animals that spend most of their short lives attached to docks, rocks or the undersides of boats. To most people they look like small, coloured plantlike growth. It often comes as a surprise to learn that they are actually more closely related to vertebrates like ourselves, than to most other invertebrate animals.

Nothing can be seen of a vertebrate relationship in the adult animals, but the tadpole-like larva has a notochord, (a stiff rod) in its tail. After hatching, this little creature, rarely more than 5mm long, swims for a few hours to find a spot somewhere on a solid surface...

Codium fragile subspecies Tomentosoides

Green sea fingers (Codium fragile) is a pale to dark green algal plant with very bush-like appearance. The branches are 5 – 10 mm in diameter, and rise from a disk shaped pad, known as a holdfast. The holdfast is responsible for keeping the plant securely fastened to rocks on the seabed. As the plant grows, the branches sub-divide into two new branches. It is an annual plant and reproduces during the summer.

Believed to be native to Japan, the sub-species tomentosoides is known locally as dead man’s fingers and is one of the most invasive seaweeds in the world. It is principally sub-tidal in the waters of the region to depths of 15m, but can be found in the inter-tidal zone...

Homarus americanus

Because they belong to the invertebrate phylum Arthropoda (see our Help pages for an explanation of taxonomic classification), lobsters are actually closely related to insects.

This relationship arises because of two main characteristics that they share: they all have an exoskeleton (outer skeleton) and they all have joint appendages. Lobsters are farther categorized into the class Crustacea, along with other marine organisms like crabs and shrimp. These crustaceans are distinguishable from other Arthropods with hard exoskeletons, like mussels and clams, because their shell is softer and more flexible. As lobsters have ten legs they also belong to the order Decapoda (derived from the Latin word, ten feet).

The American lobster (Homarus americanus), also known ...

Lutjanidae

The snappers are a large and diverse group of robustbodied, carnivorous fishes. Most species possess relatively large mouths with stout canine teeth and bodies covered with relatively large, coarse scales. They are frequently brightly coloured. They are demersal (spending most time swimming close to the sea bed) in some cases down to 450m and are found in the tropical and sub topical waters of the Atlantic, Indian and Pacific Oceans.

There are over one hundred individual species globally, but within the North America – Atlantic Coast – temperate eco-region there are only a limited number of species that you are likely to see at diving depth, and these will tend to be in the warmer waters of the region.

The dog snapper (Lutjanus jocu) is the largest member of the f...

Scombridae

The Scombridae family of tuna and mackerel are fast-swimming, wide-ranging pelagic fishes. 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.

Albacore (Thunnus alalunga) can be distinguished from other tunas by a long pectoral (breast) fin that may reach to a point beyond the anal fin. Albacore are devoid of any stripes or spots on lower flanks and belly...

Sciaenidae

The sciaenids are a large family of primarily bottom associated, carnivorous fishes distributed throughout the Atlantic, Indian and Pacific oceans, in tropical and temperate inshore waters. The majority occur on open sand and mud bottoms and some are found only in brackish waters. The exact number of species is uncertain, but there are probably about 270.

Drums are also commonly called croakers, and for good reason. They have modified muscular swim bladders that they use to produce a drumming or croaking sound when they are excited. Drums are luminescent and appear pink when first removed from the water. A drum’s tail is slightly pointed, and it has faint stripes across its back and small chin barbels...

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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Gadidae

The family Gadidae of cods and haddocks is found primarily in the circumpolar and temperate seas of the Atlantic, Pacific and Arctic oceans, principally in the northern hemisphere. A commercially important fish, cods are normally found swimming in schools at moderate to deep depths and feed on a variety of invertebrates and other fishes. Some species are noted for their habit of long-distance migration.

One of the most common in the region is the Atlantic cod (gadus morhua), to be found in the benthopelagic zone and in brackish waters, at depths of 1 – 600m. This species is widely distributed in a variety of habitats from the shoreline to well down the continental shelf. It is omnivorous and feeds at either dawn or dusk.

Another common member of the family is the hadd...

Pterois volitans

A member of the Scopaenidae or scorpion fish family, the red lionfish (Pterois volitans) is commonly found in the Indian and Pacific oceans. The species ranges from western Australia and Malaysia to the Marquesas Islands. It is not a native of this eco-region, but in the last few years, there have been increasing reports of the species being seen off the coasts of Georgia and Eastern Florida. Research scientists want to document all sightings, collections and other incidents relative to this species as well as other non-native marine species. They would also like to learn more about their distribution, abundance and habitat preference in the region.

The red lionfish has distinctive red to purple color with vertical white stripes, fleshy tentacles above the eyes and be...

Lutjanidae

The snappers are a large and diverse group of robust-bodied, carnivorous fishes. Most species possess relatively large mouths with stout canine teeth and bodies covered with relatively large, coarse scales. They are frequently brightly coloured. They are demersal (spending most time swimming close to the sea bed) in some cases down to 450m and are found in the tropical and sub tropical waters of the Atlantic, Indian and Pacific Oceans. There are over one hundred individual species globally, but within the North Atlantic Coast Sub-tropical eco region there are only a limited number of species that you are likely to see at diving depth,

The cubera snapper (Lutjanus cyanopterus) is the largest member of the snapper family and the only one on our list that is on the IUCN R...