The Salton Sea is the largest inland body of water in California. Prior to 1950 the Sea contained only four species of fishes, and two of these never exceed two inches in length. The nearest approach to a sportfishery was a snag-fishery for striped mullet which attracted a considerable number of local residents each year. However, by 1950 even this fishery had started to decline.

Situated near one of the greatest centers of population in the United States and in a region of scarcity of inland water resources, the Salton Sea provided a constant challenge to those men interested in the full utilization of resources for the sportsman. Several attempts to introduce game fishes met with failure. The problem was a difficult one, for the waters of the Sea were salty, but the relative amounts of constituent salts were different from those found in the oceans. In addition, the temperature fluctuated greatly. The little that was known about the environmental variables did not provide much hope for establishing a sportfishery.

In spite of the difficulties and poor prospects, the California Department of Fish and Game, with encouragement from Harvey A. Hastain (then Fish and Game Commissioner from Brawley) renewed its attempts to establish new species of fishes in 1948. Philip A. Douglas, Willis A. Evans (both in 1948), and John E. Fitch (in 1950) were assigned the tasks of locating, capturing, and transplanting desirable species. Attempts were made to secure anchovies and anchovetas through commercial channels but mortalities were high and there seemed little likelihood for success. Consequently, other sources of stock were investigated. The greatest chance for success seemed to lie in the Gulf of California at San Felipe, Baja California. In May 1950, several thousand fishes of a dozen species were transported to the Salton Sea from San Felipe. Because knowledge was inadequate for making selected plantings, these and subsequent operations were on a "shotgun" basis: all species not undesirable were taken with the hope that one or more might adapt to Salton Sea. By the end of 1951, some 7,000 fishes from San Felipe had been introduced into the Salton Sea by the California Department of Fish and Game. The success of the 1950 and 1951 plants is now history. In July 1952, Jack Bechtel of the California Department of Fish and Game, took the first bairdiella, a 1¾-inch fish, from the Salton Sea. Douglas also reported additional collections of young-of-the-year bairdiella, and the capture of an adult corvina. Indications of the success of the introduced species gave hope that a fishery might become established.

Shortly after these discoveries and after it was certain that bairdiella were reproducing at a remarkable rate, the University of California, Los Angeles, contracted with the California Department of Fish and Game to do research basic to developing a sportfishery in the Sea: Funds were supplied by the Wildlife Conservation Board, and in March 1954, work commenced under the contract W. C. B. 126. This project was continued, on an annual basis, through 1955 and 1956, and research activities were discontinued in the fall of 1957.

A laboratory was set up in a rented motel cabin at Fish Springs. Later, as operations expanded, a second cabin was added. Construction and maintenance of research facilities were on a strictly "do-it-yourself" basis. The researchers thus had to double as handymen, and a significant portion of each man's time was occupied by such duties. Help was difficult to get, and more difficult to keep, because of the rigorous conditions for work.

From the outset it was obvious that the kinds of information gathered and analyzed by the project would need to be highly restricted. A complete job on a lake of 340 square miles could never be done in a few years' time by a staff of only three full-time researchers. We chose to do those things which we thought would produce information most apt to be useful in future management. In making these decisions, we were ably advised by a committee representing the California Department of Fish and Game and the Wildlife Conservation Board.

There were many phases of work which we wished to do but could not because of practical considerations. Sometimes seemingly essential information could be sought only in an indirect or incomplete manner, or not at all, because we lacked manpower. The researchers were forced to cover exceedingly wide areas of investigation, and therefore many of the results are incomplete. We did try, however, to carry the most essential phases to a reasonable conclusion.

The story of the spawning habits of the grunion has been worked out in some detail by Thompson (1919) and Clark (1925). Their data are entirely sufficient to give the general picture. However, there is little in their data which points toward the mechanism by which the timing of the spawning runs of the grunion is controlled. Notably lacking are continuous observations on runs, to determine exactly when they do and do not occur. This information would appear to be essential if the controlling factors and mechanism of timing are to be found. In the present work the results of continuous observations on grunion runs for a period of three years are given. The times of observed runs are correlated with various physical phenomena, in order to suggest which of these phenomena may be important agents in the timing. Since these observations extended over a period of three years, it is natural that many new details about the general life history of Leuresthes have come to light.