This final report is the result of research during the five and one-half year period from September 1948 to March 1954. Throughout the investigation the apparent decline of sport fish was causing sport fishermen great concern. Among other factors, kelp harvesting was blamed for the poor catch of the sportsman. More than a year after the beginning of this investigation, the Kelco Company approached the Scripps Institution of Oceanography of the University of California, with the request that the problems of kelp cutting in relation to the fish supply be attacked by the University under a fellowship grant, by unprejudiced research. The Company wanted to determine whether the kelp operations were adversely affecting fishing, and if so, how harvesting methods might be altered to prevent this.
The first phase of the program was concerned with observation and identification. Thousands of hours were spent above and below the surface observing the organisms in their own environment. Extensive use was made of scuba diving equipment for observations, collection, and placing of equipment. Underwater photography was developed to a point where many observations could be recorded.
The second phase of the program was to appraise the effects of kelp harvesting on fish life. Because of the lack of pertinent published data on the ecology of the inshore waters, it was necessary to investigate not only the beds of the main commercial kelp (Macrocystis pyrifera), but also many other regions, in order to obtain comparative data. Such areas included bays, rocky areas below the levels where kelp grows, rocky areas with no kelp, the surf zones, sandy areas, and regions outside the West Coast range of Macrocystis. Kelp beds were studied as far north as Monterey and as far south as the San Benito Islands, Baja California. Diving observations in the kelp were made at Monterey, Morro Bay, Goleta, Santa Barbara, Point Dume, Palos Verdes, Newport, Laguna, Dana Point, San Clemente, Del Mar, Solana Beach, La Jolla, Point Loma, Ensenada, Punta San Carlos, Punta Blanca, Punta Santa Rosalia, and numerous other points along the mainland; also at San Miguel, Santa Rosa, Santa Cruz, Anacapa, Santa Catalina, Coronado, San Martin, and San Benito Islands. Intensive studies of the problem were carried out in Orange and San Diego Counties, with special concentration on the nearby La Jolla kelp beds.
One portion of the La Jolla kelp beds was left uncut as a control. Little difference has been noted in the fish life within the bed as contrasted with harvested beds. The kelp itself became more sparse, probably because of reduced light penetration through the heavy canopy that developed temporarily. In the 1952-53 winter season much of the kelp was destroyed by storms. These studies yielded a vast amount of information bearing not only on the kelp problem but also on the life ways of the fishes.
As a result of these long and thorough studies, it is concluded that kelp harvesting, as cutrrently practiced, has no seriously detrimental effects on fishing. The various claims as to the ways in which kelp harvesting was supposed to destroy fish life and to decrease the fish catch were completely investigated and found to be in error. Spawning and nursery grounds of fish are not being destroyed. Sufficient cover and food are always available during and after harvesting. The kelp beds are not destroyed by harvesting methods. Harvesters do not frighten sportfish from an area.
For several decades California has experienced a tremendous increase in population. Cities have grown where deserts and foothills were the homes of deer, rabbits, ground squirrels, ground owls, doves,and quail. In most places these animals have largely disappeared, and with them the intertidal mollusks — Pismo clams, butter clams, abalone, and many other species. The shore fishes such as corbina and spotfin croaker are less common in the individual fisherman's catch. Over kelp beds where a man might have fished alone a decade or two ago, we may see 50 sport boats with a total of 1000 anglers. Thus, even though the annual catch may be the same as or higher than 10 or 20 years ago, the catch per fisherman is much lower.
The kelp industries have arisen indirectly from our social-economic needs for new raw materials to fill new markets. They have become established in our economy and are essential for the production of certain new products. As is typical of modern, young industries, they have conducted research to determine the maximum sustained yield. The industry naturally has no desire to destroy kelp.
The sportfishing industry is large and provides recreation, necessary for our nation's health, to thousands of persons. With the addition of thousands of newcomers to sportfishing and the reduction of catch per unit of effort, it is not difficult to understand the fishermen's concern over factors supposedly destroying their sport. It is necessary, however, to determine the real reason for the apparent decline of fish before any constructive action can be taken. It may be a problem of overfishing or of natural population fluctuations, but the blame cannot be laid to the kelp harvesting.