Below are some Sussex key species facts
Bass belong to the order Perciformes which are the ‘perch-like’ fishes]. They have two dorsal fins which are of similar size, the first being spiny-rayed the second being soft-rayed, the scales are a large thick ctenoid scale which means they have a toothed margin, this reduces hydrodynamic drag during swimming and their jaws are structured such that they can protrude/extend their mouth to create a large funnel-like cavity which facilitates in hunting. In addition they are thick bodied and streamlined, silvery in colour being slightly darker on their back and lighter on their belly and they have a dark patch on their gill covers [2 & 3]. Juveniles (up to 10 cm) often have many darker spots on their sides and back.
The common cuttlefish is a highly evolved mollusc with large eyes, tough jaws, 8 arms, 2 retractable tentacles and an internal cuttlebone . The body is flattened and oval in shape, with lateral fins running the entire length of the body . The cuttlebone is made of calcium carbonate and is used to control the animals’ buoyancy. The cuttlefish is capable of changing colour and texture very rapidly, this may be used in sexual or competitive behaviour or to camouflage.
Black bream have an elliptical, compressed body shape with a single dorsal fin which is spiny-rayed at the front, a tail fin which is forked and a small mouth which does not extend back to the level of the eye [1 & 2]. The adult colouration is silver, tinged with blue and may have broken golden longitudinal lines (although this is more common in juveniles) . Note, the seabreams are not related to freshwater breams.
Cancer pagurus is known locally in Sussex as the brown crab, it has an oval shaped body with a distinctive ‘piecrust' edge. It is reddish-brown in color with black tipped pincers.
Brill are flatfish with an oval body outline and eyes on the ‘left’ side of the head. The dorsal and anal fins run the length of the body but do not join the tail fin ; in addition the finrays at the front of the dorsal fin are branched, giving a ‘frilly’ appearance . Unlike turbot, brill have scales and no ‘tubercles’ (bony bumps) [1 & 2] but similarly they do have a lateral line which is strongly arched above the pectoral fin [1 & 2]. Their colouration and markings are variable depending on the colour of the seabed  but they are commonly greyish brown with an abundance of dark and light speckles on top and white underneath 
The European lobster is dark blue in colour with off-white markings and bright red antennae. It has two front claws that are different in shape, the right-hand claw being larger with blunt serrations used for crushing, the left-hand claw being more slender with sharper serrations used for cutting. It is a solitary animal and can be quite aggressive .
Cod are a typical fish shape with an elongated body however, quite uniquely they have; three dorsal fins, two anal fins, the upper jaw overhangs the lower jaw and the lower jaw possess a barbel . The lateral line is prominently curved and whitish in colour, above this is mottled brown in colour and below is paler, almost white . Cod often form large schools during the day .
Ostrea edulis has an oval or pear-shaped shell with a rough, scaly surface which is off-white in colour . The lower left valve is concave and fixed to the substratum, the right valve is flat and sits inside the left . The only commercial fishery for the native oyster in the Sussex IFCA district is in Chichester Harbour. It is likely that the individuals found here are part of the larger Solent population which exists in our neighbouring Southern IFCA district.
The Dover sole is a large elliptical shaped flatfish with eyes on the right side of the body, a rounded snout and a curved mouth . The dorsal and anal fin are united thus the fin runs from the eye down the whole length of the body . Generally Dover sole are greyish brown in colour with some darker blotches on the upper side  and white on the underside, but colour may vary depending on the substrate colour .
The great scallop, Pecten maximus is a bivalve mollusc (it has a shell consisting of two valves). The lower right valve is convex and off-white in colour whilst the upper left valve is flat and reddish-brown. It is has many common names including the great scallop, the king scallop, the giant scallop, escallop and Coquille St. Jacques.
The herring has the basic ‘fish’ form; one short dorsal fin, a deeply forked tail, no lateral line and a body covered in large round scales [1 & 2]. Herring are silver below and dark blue above and have a rounded belly unlike the sprats and shads which have a keel-like edge to their stomach . They are a pelagic, shoal forming, open-water species that perform extensive migrations and can be found all around the coast of the Britain . Herring is an oily fish and young herring are sold in restaurants and as whitebait .
The common whelk Buccinum undatum is a relatively large gastropod mollusc with a tall spired shell. The body of the animal is yellowish white, flecked with black and it is a popular sea food in countries around the Southern North Sea. It is common on all British coasts.
Mackerel have a long streamlined body which is rounded in section, with a row of characteristic bony scales along the lateral line [1 & 2]. There are two well separated dorsal fins and a single anal fin, small finlets extend from the second dorsal fin and anal fin to the tail, the tail is deeply forked [1 & 2]. Mackerel are iridescent blue-green on top crossed by narrow black curving bands, silvery on the flanks and white below .
The plaice is a flatfish with eyes on the right side of the body and a pointed snout/mouth. The head is less than 0.25 of the total fish length  and has line of 4 to 7 bony warts between the eyes extending to the lateral line . The upper side is dark brown with distinct orange blotches and the underside is pearly white . To some degree plaice can adapt their colour to match their substrate , thus increasing camouflage. .
Red mullet belong to the Mullidae family which are commonly known as the ‘goat fish’ and are generally associated with the tropics (despite the name they are not closely related to the grey mullet which is also found in UK waters). They have a moderately elongated body, with a steep snout and are easily recognized by their two long chemosensory barbels that protrude from the chin . They have two dorsal fins which are spaced well apart and large fragile scales [1 & 2]. Their colouration varies with depth, emotion and time of day but generally they are reddish to pink with three yellow strips along their sides [1 & 2].
Turbots are flatfish with a circular body outline and eyes on the ‘left’ side of the head. The dorsal and anal fins run the length of the body but do not join the tail fin . Turbot have no scales but they do have prominent ‘tubercles’, bony bumps that are scattered irregularly on their upper side [1 & 2]. Their lateral line is strongly arched above the pectoral fin [1 & 2] and their colouration and markings are variable depending on the colour of the seabed ; commonly they are greyish brown with an abundance of dark and light speckles on top and white underneath .