In speaking of the habits of fishes, it deserves notice that they have their particular grounds and shores which they frequent; for while the vessels attending the works at the Bell Rock were stationed there, different kinds of fish were caught as the depth and bottom varied. About high-water, and especially during ebb-tide, when the sea is smooth on the rock, the _Podley_ (chiefly the fry of the coal-fish, but including also the young of the _Gadus virens_) is so numerous, as almost entirely to cover it from view. Near the rock, the small red cod is often found in abundance: at some distance, as the bottom, which is covered with marine plants near the rock, alters to coral, gravel, shell sand, fine sand and mud, all of which occur in a range of depths from 4 to 23 fathoms towards the north, different kinds of fish are found; first, the codling, which ceases to be wholly red, but becomes only speckled with reddish spots; then, upon the finer or mud grounds in the track of the tides of the Firth of Tay, whiting, haddock, flounder, and occasionally the sole. On the southern side of the rock, where the water deepens to 35 fathoms, the large white cod, in company with ling, conger-eel, halibut, skate, thornback, plaise, turbot, wolf-fish and large coal-fish are found. The dog-fish appears to be very general, and seems to prey chiefly upon the haddock and cod. The mackerel and gurnard are found together near the surface, and do not seem to be confined to particular grounds, but occur wherever the water is of a considerable depth. Herrings are found in the bays of the opposite shores in great abundance at the fishing season, when they are understood to be migrating towards the south. It has often been observed, in the course of the Bell Rock operations, that, during the cold weather of spring and autumn, and even at all seasons, in stormy weather, when the sea is much agitated by wind, the fishes disappear entirely from the vicinity of the rock, probably retreating into much deeper water, from which they do not seem to return, until a change of weather has taken place; so much was this attended to by the seamen employed on this service, that they frequently prognosticated and judged of the weather from this habit of the fishes, as well as from the appearances of the sky. _Depth of Water._ [Sidenote: Depth of Water.] [Sidenote: Depth of Water upon the Bell Rock.]