Gobiidae
by P.J. Miller
A large family (perhaps to 1,800 species) of percomorph teleosts, chiefly tropical and warm temperate benthic, typically inshore marine but many estuarine and freshwater.
Clofnam gobies are small, mostly below 15 cm, all less than 28 cm, except by far the largest, Mesogobius barachocephalus at 34.5 cm. Among the smallest European fishes are the gobiids Corcyrogohius liechtensteini and Odondebuenia balearica, not exceeding 3.2 cm. In body form, gobies are typically moderately elongate, subcylindrical to compressed, with depressed head, dorsolateral eyes, narrow inter-orbit and prominent rounded cheeks. Two nostrils are present on each side of the snout, the anterior more or less tubular, sometimes with a rim process, the posterior usually pore-like, near the eye. There are 2 dorsal fins and 1 anal fin, the first dorsal usually with 6 or 7 flexible spines, the second dorsal and anal fins of a single spinous ray and typically about 8-14 branched rays, the last divided to the base. The caudal fin is usually rounded and slightly less than head length. The pelvic fins, each of a spine and 5 branched rays, are thoracic and typically united into a eakly suctorial disc with an anterior transverse membrane (frenum) between the spinous rays. Alone among Clofnam gobies, Odondebuenia and Vanneaugobius have pelvic fins separate except for a low membrane between the bases of the fifth branched rays. The pectoral fins are large, sometimes with free uppermost rays. Squamation is normally imbricate and ctenoid, with uniseriate ctenii, and scales in lateral series usually between 30 and 65 (25-85).
The lateral line system in gobies is much modified and provides important criteria for classification. A lateral line canal is absent from the side of the body and, on the head, at best development, only supraorbital, post-ocular and preopercular canals are present, with intermediate and terminal pores. Various degrees of reduction occur and all head canals may be lost. The head and body bear characteristic patterns of exposed neuromast organs (sensory papillae, ciathiform organs, genipores) of great systematic importance. The terminology (after Sanzo, 1911) for canals, canal pores and those sensory papillae series referred to in the present work is given in Figure 1. The sensory papillae and canal pores are best viewed by oblique lighting under a binocular microscope; canals may be injected with dye and the sensory papillae stained by chromic acid (Sanzo, 1911), ferric tannate (De Buen, 1923) or potassium permanganate (lljin, 1930), but treatment with acids in the first two techniques decalcifies at least superficial bony structures, and all these methods have a more or less deleterious effect on the appearance of the specimen.
In marine and brackish waters, many Clofnam gobies are very abundant, most species dwelling on or near the bottom in epibenthic or cryptobenthic ecotopes: a few are specialized neritic forms. Behaviour typically involves intermittent swimming, with short darting movements when disturbed. Territoriality may be evident. General trophic niche is that of a small predator, feeding on invertebrates, sometimes small fish. Breeding occurs in spring and summer, with repeat spawning. Eggs are pear-shaped, not more than 3-4 mm long, and deposited in a single-layered patch under stones and shells, or on other hard substrates, and guarded by the male. Young hatch as post-larvae, typically occurring in plankton above the sea-bed.
Commercial fisheries exist for larger species in estuaries of the northwestern Black Sea and especially in the Sea of Azov. Otherwise, gobies may feature among small fishes brought to Mediterranean markets by local fishing.
Genera about 200, in Clofnam area 32.
Note. The Clofnam area houses at least 52 Atlantic-Mediterranean species, a Black Sea element of 16 from the endemic Ponto-Caspian fauna, and two Indo-Pacific species of lessepsian origin. Forms new to science are still being found in the region.