Sand Smelts (family Atherinidæ) resemble the true smelts previously described, but may be readily distinguished by the anterior dorsal fin, which is small and spinous. We have two species of this family, of which Atherina presbyter is by far the more common. It is a very pretty fish, about five inches long, with a broad silvery stripe along each side. It is very common on the sandy coasts of the south, where it also enters the brackish waters of estuaries. Young anglers catch them in considerable numbers by means of rod and line; but the professional fisherman, taking advantage of the fact that sand smelts swim in shoals, captures them in large, round, shallow nets. The net is baited with bread, crushed mussels, or offal of almost any kind, and is then lowered several feet below the surface by means of a long pole, to the end of which it is suspended. It is raised to the surface at short intervals, and will often enclose dozens of fish in a single haul.
The shallow waters of our southern coasts, including the estuaries and harbours, are also frequented by the Grey Mullet (Mugil capito), of the family Mugilidæ. This fish may be distinguished from other similar species by the four stiff spines of the front dorsal fin, and by the absence of a lateral line. The mouth is small, and without teeth, and the mode of feeding is somewhat peculiar. The food consists of worms, molluscs, and various organic matter contained in the sand or mud of the bottom. It is sucked into the mouth, together with more or less of the mud and sand, and the former is strained through a special straining apparatus situated in the pharynx.
The Grey Mullet may be taken with rod and line, and bites freely when the rag-worm is employed as bait. It is often taken in the fisherman’s drag net; but, being a splendid jumper, it frequently makes its escape as the net is drawn on the beach.
Few of our littoral fishes are so well known as the Little Blennies (family Blenniidæ), which are to be found hiding amongst the weeds in almost every rock pool, and under stones as they await the return of the tide. Their bodies are generally cylindrical, and are either naked or covered with very minute scales. The dorsal fin runs along the whole length of the back, and each pelvic has one spine and two soft rays. When taken out of the water the gill-cavities widen considerably, and the eyeballs will be seen to move independently of each other, like those of the chamæleon.
Most of the blennies are very active and voracious fishes, often giving considerable trouble to the angler when fishing with a rod among the rocks. They will bite at almost anything that moves, and, completely swallowing the angler’s hook, will immediately rush into a crevice from which it is often difficult to remove them.
Most of them have tentacles on the head by which they assist their movements among the rocks and stones; and some actually creep up the rugged surfaces of rocks by means of their ventral fins. They can all live for a long time out of the water, being able to retain a supply of water in their expanded gill-chambers to keep the gills moist.
Fig. 239.—The Smooth Blenny
The Smooth Blenny or Shanny (Blennius pholis) is one of the commonest species. It reaches a length of four or five inches, and has no tentacles on the head. The Eyed Blenny or Butterfly Blenny (B. ocellatus) may be distinguished by the conspicuous spot on the spinous portion of the dorsal fin. The Large Blenny (B. gattorugine) inhabits deeper water, chiefly off the south-west coast, and reaches a length of a foot or more. The Crested Blenny (B. cristatus) is named from the small crest on the head which can be raised and depressed; and the Viviparous Blenny (Zoarces viviparus), as its name implies, brings forth its young alive. The last species often exceeds a foot in length, and is found principally on the north and east coasts. The newly-born young are so transparent that the circulation of the blood within the body may be seen under the microscope quite as easily as in the web of the frog’s foot and in the tail of the tadpole.