UC San Diego Library – Scripps Digital Collection

This bulletin is one of three large publications summarizing kelp investigations at the University of California's Institute of Marine Resources. The general objective of the bulletin is to assess the impact of man's past, present, and future activities on the kelp-bed environment. Possibilities for future improvement are examined in the opening chapters which describe the life history of the giant-kelp plant and show how this knowledge can be used for culturing and transplanting. Ecology of kelp-bed fishes is treated in detail as a background for evaluating influences of human activities. The distributions and ranges of physical parameters important to fishes are outlined with emphasis on temperature, wave action, visibility, and topography. Diets, behavior, preferred habitats, abundances, and life histories of kelp fishes are described, showing the ecological roles played by kelp as a food source, shelter, attractant, and vehicle for making phytoplankton productivity more available to associated fauna. It was found, however, that kelp was not a habitat requirement for most fishes, nor did it increase species diversity significantly. There was evidence that it may contribute to greater standing crops of fishes but bottom topography was considered a more important attractant. It was estimated that kelp harvesting removed an annual maximum of about 10 percent of the food supplies available for fishes. This was not considered serious because generally there appear to be ample food reserves in kelp beds.

Statistical correlations were sought between harvest returns and sportfish catches and catches per unit of effort. Neither statewide totals nor selected situations representing southern, northern, and island environments yielded any relation. Analyses were broken down to the more important groups or species of sportfishes and the only relation observed was a negative correlation between California barracuda catches and harvest yields. Since barracuda are pelagic the relation was considered to be indirect, resulting from interactions with ocean temperature. Fishing was better in beds harvested more frequently. Fishing in deteriorating beds was analyzed. Generally emphasis shifted to new groups of sportfish when more conventional fisheries declined. Statistical treatment was extended to comparisons of adjacent kelp beds that had been subjected to quite different intensities of harvesting. Harvest yield was not affected by harvesting intensity for the 11-year period examined.

Kelp was sampled as it came aboard a harvesting vessel and about one third of the motile canopy fauna was removed from the habitat. The attached fauna, however, was entirely removed. Physiological studies indicated that cutting did not influence photosynthesis in adjacent kelp tissues of the cut frond. Growth of young fronds was, in some cases, retarded for periods up to a month but in other cases growth was stimulated. The complex interplay of environmental variables probably determined the character of any changes in growth rate. The interplay was described by a mathematical model and five cutting experiments were undertaken to test model predictions. Results were considered satisfactory.

It was generally concluded that giant kelp encourages development of a rich associated fauna. No adverse influence of harvesting could be found among the statistics or field observations for the periods studied. The need for intelligent management is stressed to ensure that optimum utilization of the kelp resources will continue.

Sea surveys were initiated in the spring of 1965 to obtain estimates of population size, mortality rates, and growth rates of the northern California ocean shrimp population. From March 1965 through September 1968, nine surveys were conducted in a 270-square-mile area from off Mad River, California, north to Smith River, California. Four surveys were conducted in a 105-square-mile area off southern Oregon during 1967 and 1968. Estimates of the California population ranged from a low of 2.2 million pounds in the fall of 1966 to a high of 8.1 million pounds in the fall of 1967.

Survival rates, derived from natural mortality rates for ocean shrimp during their second winter of life, for the 1964 and 1965 year classes were 0.68 and 0.55 respectively. Lowest survival rates were obtained from the 1963 and 1964 year classes during their third winter of life. The highest fishing mortality rates were observed for shrimp during their third summer in the fishery. Survey data indicate a relationship between annual fishing mortality rates and total trawling hours expended by shrimp fishermen. Limited data suggest a relationship also exists between the number of spawners and 1-year-old recruits as well as the existence of a density dependent relationship between population size and survival of the incoming year class.

The Von Bertalanffy growth equation was applied to mean carapace lengths of 1964 and 1965 year class shrimp. Values for the constants L and K were very close while the values to t0 varied considerably.

I believe the spring and summer 1965 and fall 1966 surveys produced underestimates of abundance, possibly due in part to vertical migrations of shrimp during daylight in 1965 and a horizontal shift of the population north in 1966.

Catch bulletins provide records of California's commercial fisheries and their value to fishermen. They also summarize the marine partyboat angler's catch. The report for 1964 is the 24th in the series. Prior records have been published regularly beginning with those for 1926 and 1927. In recent years, catch bulletins have been published annually instead of biennially. Records are obtained from each wholesale fish dealer or processor who receives fish from fishermen or who processes fish. Partyboat operators record each trip's catch, and these records are also sent to the Department. Clerical personnel in strategic locations (Eureka, San Francisco, Monterey, Terminal Island, and San Diego) maintain contact with fish dealers and local Fish and Game wardens to insure that the records are accurate and transmitted promptly. All data are edited and subsequently processed by electric accounting machines. Published figures are of national and international concern, but they are used primarily by fisheries scientists and state legislators to manage and regulate California's important fisheries. Chambers of commerce, members of the fishing industry, educators, and others also find these catch statistics of value.

Most lower elevation California lakes experience one yearly cycle of stratification. Thermal stratification generally starts about March and extends through November, greatly influencing chemical and biological stratification. The metalimnion and hypolimnion of eutrophic lakes often are devoid of oxygen. Concomitant with the oxygen deficit is the build-up of anaerobic decomposition products and the exclusion of biota from the oxygen deficient zones.

Artificial destratification by aeration reduces or eliminates thermal stratification. Oxygen is distributed to all depths and products of anaerobic decomposition are oxidized. Barriers to biotic distribution are minimal.

The diffuse aeration system is probably the most effective for destratifying large lakes. Other methods are discussed.

Artificial lake destratification increases the lakes's heat budget. The winter temperature regime is not affected by destratification. Summer surface temperatures during stratified and destratified periods are about equal. Bottom temperatures are greatly increased by destratification and may equal the surface temperatures. The coldest water temperature in a destratified lake may approach those found at the lake's surface during stratified periods. This increased heat content should benefit the fishery by increasing invertebrate forage production and decomposition of organic sediments. However, increased bottom temperatures may eliminate or preclude the establishment of a coldwater fishery.

Two hypolimnion aeration systems are discussed. These systems aerate the bottom waters without causing thermal destratification and enhance coldwater fisheries.

Lake aeration is economically feasible. Evaporation and chemical treatment savings alone may more than pay for the aeration system. Improved drinking water quality and fishery habitats results from aeration.

This report is the first of a series describing our El Capitan Reservoir destratification study. Subsequent reports will describe the effects of artificial destratification on the zoobenthos, phytoplankton and fishes.

Starting with the 1941–42 sardine season, a comprehensive age-reading program on the Pacific sardine or pilchard, Sardinops caerulea, was undertaken along the Pacific Coast of North America. These readings were based on scales from fish in the commercial catch with collections made by the Fisheries Research Board of Canada, the Washington State Department of Fisheries, the Fish Commission of Oregon, the California Division of Fish and Game and the U. S. Fish and Wildlife Service. The actual age interpretations were made jointly by the members of the latter two agencies and were published by Felin and Phillips (1948). Tables 1 – 6, reproduced from Felin and Phillips, list the number of fish, mean length and standard error of the mean for each year-class for each season, 1941–42 through 1946–47, by region of catch. In addition, Table 7 lists the number of fish and mean length for each age during the period 1941–42 through 1946–47, combined. In the presentation of figures that follow, no averages have been plotted for any year wherein fewer than 10 fish are represented. The left-hand vertical scale of each figure shows the body length2 in millimeters, while the righthand vertical scale shows the corresponding total length in inches. The horizontal scale at the bottom of each figure lists the actual number of observed rings and also the corresponding approximate age that each ring represents. As age is estimated from the number of annual rings present on the scale, 0-ring fish are those that are in their first year of life before the first winter ring is formed and 1-ring fish are those that have formed one winter ring between late fall and early spring, etc. Thus, a fish which is caught in the winter fishery and shows one annulus well inside the margin of the scale is in its second year of life. Since the commercial sardine fishery along the Pacific Coast is conducted almost entirely during the late summer, fall and winter months, the actual ages of the fish are approximately one year more than that indicated by the number of rings. Even though a second annulus has formed recently during a current winter, for example in a scale that already has one annulus formed during the previous winter, that fish is still referred to as a 1-ring fish, and the second annulus is indicated as "forming" or "new" until the end of that season. The following general observations concerning the life-history of the sardine are reviewed as an aid in interpreting the results of this study: This species ranges from southern Alaska to Cape San Lucas and into the Gulf of California. However, there is strong evidence that sardines found in southern Lower California and the Gulf of California constitute a separate population which rarely intermingles with the northern population but that a considerable, and perhaps variable, amount of interchange takes place throughout the range of the northern population from Alaska to Pt. San Eugenio in central Lower California. Exploratory work indicates that spawning may occur throughout the range of the sardine population, usually 50 to 200 miles offshore, but that the heaviest concentration is off Southern California. In this region, the spawning season extends from about January through June with a peak in April. Important nursery grounds are known off Southern California and Lower California and nursery areas of lesser importance may extend as far north as British Columbia. The young that result from the spring spawning in Southern California waters may remain on the nursery grounds in Southern California and Lower California for six months or a year. In their second year, if not earlier, they exhibit some northward movement and the extent of this northward movement increases year by year, with the largest and oldest fish eventually reaching the waters of the Pacific Northwest. A study of the size composition of samples and of tagging results indicates extensive migrations for a large portion of the stock, the largest and oldest fish undertaking the greatest movements. An influx of large fish into the Pacific Northwest fishery in the summer is followed by the appearance of these large fish in the California fishery in the winter preceding the spring spawning season. (Clark, 1935, 1940, 1947; Clark and Janssen, 1945; Hart, 1934, 1943; Scofield, 1934.)

This bulletin is meant to be a guide to the fishes of the west-central coast of North America that commonly occur in kelp beds and adjacent areas. The fishes described are common species, and this report is not meant to include all species that occur in the kelp environment and adjacent zones. In all, 97 species are described; key identification features are given. Colors listed for each species refer to how that specimen would appear in the live and/or recently captured state; underwater behavioral characteristics are given wherever possible to aid the underwater diving enthusiast. Description of the kelp environment is given, which includes a brief explanation pertaining to the three major ecological zones within the kelp ecosystem. A brief explanation and description of the kelp bed flora is included, along with geographical considerations. The kelp environment as a habitat type for fishes is discussed; three habitat regions in the kelp bed are given special attention, these are: 1) the canopy, 2) intermediate regions, and 3) kelp bottom holdfast region. Accounts of each species of fish then follow which include identification, distribution, size, habitat habits, and life history inclusive of food and reproductive biology whenever available. Four appendix tables include listings of the organisms frequently observed by diving in the various kelp bed habitat regions.

In 1926 a few complaints and several petitions were received by the Division of Fish and Game from the fishing industries regarding damage to fishing by seals and sea lions. Early in 1927 the complaints became more numerous. This was the direct result of propaganda by sea lion hunters from Oregon. These men have hunted sea lions for several seasons for a bounty in the state of Oregon. As the sea lions in Oregon are becoming scarce, due to their activities, they made a trip along the coast of California, stopping at all the principal fishing centers, locating the rookeries, and talking to the fishermen, with a view to hunting in California. As there was no possibility that the Division of Fish and Game would consider a bounty on seals and sea lions, the hunters tried to interest the fishermen to the extent of raising a fund with which to pay a small bounty. The fishermen's organizations agreed to raise the fund, but nothing has been done toward it to date. The fishing industries, in their complaints, set forth as their grievances that the seals and sea lions are very numerous; that they are on the increase, and that they take enormous quantities of fish and cause considerable damage to gear. There are two species of sea lions: Steller's sea lion (Eumetopias stelleri); the California sea lion (Zalophus californianus), and the one species of seal, the harbor seal (Phoca vitulina), found on the coast of California.

This study of the variation in certain commercially important clupeoid fishes of western North America is one of a series by which it is designed to determine the relation which the varying characters of fishes bear toward the physical features of their environment. Although other characters and other environmental factors are receiving attention in these investigations, chief stress is now being laid on the correlation between the average number of vertebrae and the temperature of the water. The average surface temperature of the coast waters of San Francisco Bay (Golden Gate), Monterey Bay (Pacific Grove) and San Diego (off Coronado Beach) is indicated for the whole year by the three curves on Plate I. The marked difference in temperature between the ocean water of southern California and central California is illustrated by the curves for the San Diego region and for Monterey Bay, which is really a very open gulf. The usual maximum temperature for Monterey is lower than the ordinary minimum off San Diego. These is not an even gradation of temperature between these two localities, Point Conception marking the boundary between the cold waters of the central coast and the warmer waters of southern California. In each region, moreover, there is much local variation in temperature conditions, due not only to differences in protection and depth, but also, probably, to the differential upwelling of deep, cold water (McEwen, 1912, 1916). The curve for San Diego is taken from McEwen's 1916 paper; that for Monterey is smoothed from unpublished data supplied by Director Walter K. Fisher of the Hopkins Marine Station at Pacific Grove. The temperature curve at the entrance to San Francisco Bay, constructed by slightly smoothing Davidson's (1886) monthly averages, is intermediate between the San Diego and the Monterey Bay curves. The higher temperatures at San Francisco as compared with the Monterey records are due to the greater warming of the waters in the shallows of San Francisco harbor. As the fishes here treated are of great importance from the standpoint of the commercial fisheries, this paper is published in the present form largely as a contribution to the fishery-biology of these species. An attempt to determine definitely the racial status of the various populations of each form would, however, be beyond the scope of the present paper. Our data, however, are brought to bear on such problems. This is done to suggest conclusions, and to make our data available to the fishery investigators. We have applied to our data on the herring and the anchovy a method of analysis which we have found useful in studying the seasonal variation in the number of segments in freshwater fishes (Hubbs, 1922, 1924). By this method the correlation between individual variations and environmental factors is determined. Measure is obtained, also, of the degree to which the average number of segments fluctuates on a purely individual, as contrasted with a racial basis. The results so secured are of value in interpreting the significance of observed differences in the average number of segments for samples from different localities.

Any person associated with the sardine industry is well acquainted with the progressive increase in length of the sardines taken throughout a fishing season. Small and mixed sizes are taken in the summer months, while the winter fishery consists chiefly of large fish. Such a seasonal variation is not common or, at least, has not been reported for any other important commercial fish in California. It is of primary interest, then, to define this trend in the sizes of sardines throughout each season and to compare the trends from year to year. During the past eight years, 1919–1927, the California State Fisheries Laboratory has made a detailed study of the sardine catch at Monterey. These records supply data for lengths of a representative sample of the catch for the entire fishing season and thus reflect changes in size from day to day, week to week and month to month.

Prior to 1928, the Pacific mackerel fishery was of minor importance, the catch being almost wholly absorbed by the fresh fish trade. Since that year, a large scale canning industry has developed in Southern California with an almost unlimited demand for fish. The bulk of the catch is processed in the Los Angeles Harbor area though large tonnages are handled at Newport Beach, some thirty miles to the south. Small amounts are canned at San Diego and at Ensenada, Mexico, the southern limit of the fishery. In Central California, mackerel are sometimes landed mixed with sardines (Sardinops caerulea) caught by the San Francisco and Monterey purse seine fleets. The quantity taken is rarely sufficient to warrant segregation for canning, and the mixed loads are for the most part reduced as "sardines." As a result, there is no record of the actual tonnage of mackerel handled at these ports.

The Southern California fishery for the canneries was at first prosecuted largely by net boats, first the lampara and later the purse seine fleet accounting for most of the catch. Since 1939, the emphasis has shifted to a large fleet of small "scoop" boats. The crews of these vessels, usually two or three men, fish with ground bait and dip the mackerel with a long-handled brail. The total catch has fluctuated widely from year to year with little relation to economic demand. Monthly landings reach a peak in the fall and winter months; there is a period of scarcity, apparently associated with spawning, which usually occurs in the spring but sometimes extends from mid-winter to early summer. For the period covered by this report the season is regarded as commencing in June and closing the following March.

The biological range of the species far exceeds the commercial, extending from the Gulf of Alaska southward into the Gulf of California. Mackerel are known to be abundant along much of the Lower California coast and heavy spawning occurs in Mexican waters. The population is apparently limited north of Central California and does not support a fishery above Monterey Bay.

The mackerel fleet operating out of Los Angeles Harbor (including for this report the City of Long Beach as well as the San Pedro, Wilmington and Terminal Island districts which comprise Los Angeles Harbor proper) exploits a large portion of the waters off Southern California. The purse seine fleet for both mackerel and sardines ranges from near Pt. Conception in the north to the Oceanside region in the south, and offshore to the Channel Islands. The scoop fleet covers Santa Monica Bay, the mainland coast as far south as Newport Beach, and offshore around Santa Catalina Island. Virtually the entire catch landed at Newport Beach is made by scoop boats fishing along the mainland coast between Huntington Beach and San Onofre and at Santa Catalina Island. At times this fleet will work south to Oceanside. Fishing at San Diego is carried on within twenty-five miles of port and is generally of minor significance.

At the present time (1948), there is no regular mackerel fishery in Central California. Until about 1941, a small hook-and-line fleet operated in Monterey Bay, supplying the fresh fish markets. The sardine fleet, which takes mackerel incidentally, operates between Pt. Reyes (30 miles northwest of San Francisco) and Pt. Buchon, about 100 miles south of Monterey. The San Francisco fleet fishes from north of Pt. Reyes to Monterey Bay.

With the tremendous increase in the commercial importance of mackerel, the California Division of Fish and Game instituted a research program designed to provide sufficient knowledge of the species to permit its proper management. Of basic importance was an understanding of the movements of the fish — whether the Southern California fishery was exploiting one or more of several independent populations existing throughout the range or whether and to what degree fish from other areas contributed to the local catch. The tagging program was devised originally in 1935 with this question in mind. It later seemed possible that tag returns might be used in studies of abundance and an intensified program was pursued in 1940 and 1941. With the outbreak of war, field work was greatly curtailed, though a few fish were tagged in the winter of 1942–43. Tags were collected through the 1946–47 season.

Three progress reports have been issued. These papers give more detailed information as to fishing methods and tagging techniques than is contained in the present publication, which does summarize the more pertinent data.

The tagging program demonstrated that mackerel from as far north as Oregon and as far south as the central portion of Lower California eventually entered the Southern California fishery. There was no evidence of a cyclic movement, although tagging in Lower California was not so conducted as to show such movement. There were indications of gradual dispersion over a period of years from the point of release. No fish were tagged south of central Lower California. There were few returned from this region and it seems probable that mackerel from farther south contribute little to the fishery.