Mussel Community Studies [Year Three].

The communities associated with Mytilus californianus (mussel) beds from 20 geographic sites in southern California were examined. The study areas included six mainland sites - Government Point, Goleta Point, Ventura, Corona del Mar, Carlsbad, and San Diego,and two sites on opposite sides of seven offshore islands - San Miguel Island, Santa Rosa Island, Santa Cruz Island, Anacapa Island, San Nicholas Island, Santa Cruz Island and San Clemente Island. : The mussel communities from all areas contributed to the master species list which now encompasses conservatively, 610 species of animals and 141 species of algae. The most diverse collection came from Cat Rock, Anacapa Island where the mussel beds supported 174 species of invertebrates. The lowest diversity was recorded for mussel beds from Ben Weston, Santa Catalina Island which contained 46 species. In general, the island mussel beds supported a greater diversity of both animals and plants. Mussel community samples were collected from upper and lower intertidal areas occupied by the mussel beds within a locality. Community differences in both composition and abundance were associated with these collections. Overall. community similarity analysis revealed five major patterns which corresponded to characteristic species assemblages occupying the mussel beds from the various geographic areas. The patterns included: (1) clusters of localities which display a north-south geographic pattern with respect to the similarity of their respective mussel communities, (2) a separation of selected island and mainland communities because of dissimilarities in their species composition, (3) differences between mussel communities. on opposite sides of the offshore islands, (4) clusters of species whose highest abundances characterize selected localities, (5) species groups ubiquitous to all mussel beds examined. The results of the community analysis further suggest that predictions can be made delineating the probable mussel community inhabitants of areas not sampled. The species distribution patterns observed appear to correspond in part to the influence of currents and water masses which bear planktonic larvae and impinge on selected localities. The most important mussel bed features associated with community differences were quantitative and qualitative differences in the potential microhabitats. Those features associate~ with greater species diversity include the pore base of coarse fraction shell and rock debris, skewness and kurtosis of the sediment grain-size distributions and mussel bed thickness. Those features associated with lower species diversity included the quantity of tar. and rock and shell debris trapped within the mussel bed. (PDF contains 51 pages)

Cruise Report 62-S-2 - California Halibut

(PDF contains 2 pages.)

Final Supplemental Environmental Document Pacific herring commercial fishing regulations (Sections 163, 163.1, and 164, Title 14, California Code of Regulations)

(PDF contains 63 pages.)

Environmental Studies of Monterey Bay and Central California Coastal Zone. First half-year of operation, July 1970-February 1971

(PDF contains 141 pages)

Some aspects of the temperature, oxygen and nutrient distributions in Monterey Bay, California. Annual Report, Part 1, 1973

Seasonal variations in temperature, dissolved oxygen, and nutrients in the nearshore areas and in the canyon area of Monterey Bay, California during 1971-1972 were similar~ During upwelling periods, however, water in the nearshore areas was higher in temperature and oxygen and lower in nutrients than water in the canyon area~ This was caused by upwelled water moving north and south of the canyon into counterclockwise and clockwise flow in the northern and southern ends of the bay respectively. The water was heated by insolation and depleted of its nutrients by photosynthesis during this movement. The residence time of water in the nearshore northern and southern bay during upwelling is estimated to be 3 to 8 days, and this fits well into the above circulation pattern and average measured current velocities of 10 to 15 cm/sec~ There is sorne evidence that this circulation pattern and the estimated residence time may be also valid for on-upwelling periods. Upwelling apparently occurred in Monterey Submarine Canyon at rates of 0.4 to 2.9 m/day and was stronger in 1971 than 1972. (PDF contains 107 pages)

California Cooperative Fisheries Investigations. Hydrographic data report. Monterey Bay. July to December, 1974

In July 1974 Moss Landing Marine Laboratories began the continuation of the bi-weekly hydrographic observations in Monterey Bay. From 1951 to this date, these stations were sampled by personnel at Hopkins Marine Station in Pacific Grove. Small changes were made in the sampling routine: 1) to facilitate squid (Loligo opa1escens) studies, our observations were made at night, and 2) stations 1125 and 1154 are sampled in addition to five stations originally used by Hopkins Marine Station (2201, 2202, 2203, 2204, and 2205). These additional stations will provide important data of the nearshore environment. PDF contains 86 pages)

California Cooperative Fisheries Investigations. Hydrographic data report, Monterey Bay, January to December 1977

The data contained in this report were obtained as a continuance of the nearly bi-weekly hydrographic observations initiated by personnel at Hopkins Marine Station over two decades ago. These observations have been supported through the years by the State of California Marine Research Committee, California Cooperative Oceanic Fisheries Investigations. Since July 1974, the hydrographic sampling program has been carried out by the investigators at Moss Landing Marine Laboratories. From July 1974 to June 1976, this work was done in conjunction with an interdisciplinary study of the squid, Loligo opalescens, supported by the National Office of Sea Grant 'via the University of California Sea Grant College Project Number R/F-15. Five of the original CalCOFI stations (2201, 2202, 2203, 2204 and 2205) have been-retained in our sampling routine and additional inner-bay stations have been added (1154 and 1121) Sampling was conducted on a monthly basis for the entire year. All observations were made ab9ard R/V OCONOSTOTA. (PDF contains 93 pages)

Chinook salmon spawner stocks in California's Central Valley, 1989: annual report

This report covers the 37th annual inventory of chinook salman, Oncorhynchus tshawytscha, spawner populations in the Sacramento-San Joaquin River system.-It is a compilation of reports estimating the fall-, winter-, late-fall-, and spring-run salmon spawner populations for streams which were surveyed. Estimates were made from counts of fish entering hatcheries and migrating past dams, froro surveys of dead and live fish and redds on spawning areas, and from aerial counts. The estimated 1989 total escapement of chinook salmon in the Central Valley was 205,990 fish. This total consisted of 181,864 fall-, 12,171 spring-, 539 winter-, and 11,416 late-fall-run spawners. All of the spring-, late-fall-, and winter-run salmon were estimated to be in the Sacramento River system, while 3,493 fish of the fall run were in the San Joaquin River system. Due to decreases of spawner populations in most Central Valley tributaries, the total 1989 salmon stock was 32% lower than in 1988; however, late-fall salmon in the upper Sacramento River had a run size similar to that of 1988. The winter run in the mainstem Sacramento River was at a record low level. (PDF contains 44 pages.)

Feeding Ecology of Humpback Whales in Continental Shelf Waters near Cordell Bank, California

Daytime feeding behavior of humpback whales (Megaptera novaeangliae) in Gulf of the Farallones, California, and adjacent waters was observed during autumn of 1988 to 1990. Bodega Canyon, Cordell Bank, and the Farallon Islands were the primary sites of feeding activity. Fecal samples of whales and zooplankton tows contained euphausiids exclusively, dominated by Thysanoessa spinifera (79%), with lesser amounts of Euphausia pacifica (14%), Nyctiphanes simplex (4%), and Nematoscelis difficilis (3%). In 1988 and 1990, whales also were infrequently observed feeding on small schooling fish, presumably Pacific herring (Clupea pallasii), northern anchovy (Engraulis mordax), and juvenile rockfish (Sebastes spp.). Feeding was the most common behavior observed (52%), and less frequently traveling (23%), milling (21 %), and resting (4%). Whales used different methods to consume euphausiid prey at the surface (0-10 m), in shallow water (11-60 m), and deep water (61-140 m). Humpback whales fed at the surface 56% of time in 1988 and 32% of time in 1990, using primarily lateral lunges to capture swarms of euphausiids. In 1989, no surface feeding was observed; however, deep, long-duration dives were followed by extended surface intervals with many respirations. These 1989 observations coincided with increased prey depth as indicated by depth sounder records of diving whales and prey scattering layers. In 1989, increased prey depth and associated feeding behaviors were strongly associated with unusually high surface temperatures, calm seas, and changes in water circulation. Environmental conditions in 1989 triggered the most intense and wide-spread occurrence of red tide in this region since 1980. Red tide samples collected throughout this period contained Alexandrium (=Gonyaulax) catenella and Noctiluca scintillans. Surface feeding was observed only in 1988 and 1990, when surface prey were available and red tides were very limited in extent, duration, and intensity. Annual variations in humpback whale feeding behavior were related to prey availability which is affected by corresponding environmental conditions. (PDF contains 94 pages)

Northern range extension, abundance and distribution of Pacific coastal Bottlenose doplhins (Tursiops truncatus gilli) in Monterey Bay, California

Pacific coastal bottlenose dolphins (Tursiops truncatus gilli) have apparently moved to Monterey Bay as a result of a shift north of their known range. Between 1983 and 1993, 417 sightings were reported off central California. Eighty-four boat-based surveys, between October 1990 and November 1993, resulted in the photo-identification of 68 uniquely marked individuals. School size ranged between 2 and 35 animals (mean = 16.60, S.D. = 7.72). Forty-three (63%) of the dolphins identified were previously photographed in the Southern California Bight before 1989. Jolly-Seber population estimates indicated an increase in the Monterey Bay population from 1990 to 1993. At least 13 of the photo-identified dolphins were present in Monterey Bay throughout the study period. All but two of the calculated coefficients of association were 0.35, indicating a strong bond among resident animals. The occurrence of an El Niño from January 1992 to the end of 1993 may have affected the number of animals present in the bay: mean school size was significantly greater during El Niño.

Social ecology of bottlenose dophins in Monterey Bay, California

Between 1990 and 1995, Pacific coastal bottlenose dolphins (Tursiops truncatus gillii) were studied using photo-identification during 228 boat-based surveys of the coastal strip (<1 km offshore) between Marina and New Brighton Beach in Monterey Bay (18 km of coastline). The study period encompassed 3 regular (1990, 1991 and 1995) and 3 El Niño years (1992, 1993, 1994). Based on dorsal fin markings, 97 unique individuals were identified. Eighteen animals (19%) showed a high level of site fidelity (defined as presence in at least 5 of the 6 years), although their overall range was larger than the study area. Thirty-eight animals (39%) were transient, leaving for periods of time, and 41 (42%) were occasional encounters. The rate of discovery indicated a pulsed recruitment of new individuals into the study area, with periods of stable school composition, especially during non-El Nino years, and periods of high school fluidity. Encounter rate was significantly higher in El Niño (81%) than non-El Niño years (61%). School size averaged 16 individuals (C.I.3, =0.05) and was significantly larger in El Niño years. Schools where calves were present were twice as large (mean=15; S.D.=8) than schools without calves (mean=8; S.D.=6). Newborns represented 12% of the sightings and were seen year round with a peak in summer and fall. Crude birth rate ranged between 0.09 and 0.17 (mean=0.13; S.D.=0.03). Five females calved in consecutive years and a resident female calved once a year for the duration of the study, possibly indicating a high rate of mortality for calves in this area. Individuals often traveled as subgroups of more consistent composition than the school itself, possibly indicating that a stronger social bond exists within these units which may function as “bands” (sensu Wells 1991) of same sex individuals traveling within a larger school of mixed composition. (ppt file of poster)

Distribution, Abundance, and Biological Characteristics of Groundfish off the Coast of Washington, Oregon, and California, 1977-1986

We compare results of bottom trawl surveys off Washington, Oregon, and California in 1977, 1980, 1983, and 1986 to discern trends in population abundance, distribution, and biology. Catch per unit of effort, area-swept biomass estimates, and age and length compositions for 12 commercially important west coast groundfishes are presented to illustrate trends over the lO-year period. We discuss the precision, accuracy, and statistical significance of observed trends in abundance estimates. The influence of water temperature on the distribution of groundfishes is also briefly examined. Abundance estimates of canary rockfish, Sebastes pinniger, and yellowtail rockfish, S. Jlavidus, declined during the study period; greater declines were observed in Pacific ocean perch, S. alutus, lingcod, Ophiodon elongatus, and arrowtooth flounder, Atheresthes stomias. Biomass estimates of Pacific hake, Merluccius productus, and English, rex, and Dover soles (Pleuronectes vetulus, Errex zachirus, and Microstomus pacificus) increased, while bocaccio, S. paucispinis, and chilipepper, S. goodei, were stable. Sablefish, Anoplopoma fimbria, biomass estimates increased markedly from 1977 to 1980 and declined moderately thereafter. Precision was lowest for rockfishes, lingcod, and sablefish; it was highest for flatfishes because they were uniformly distributed. The accuracy of survey estimates could be gauged only for yellowtail and canary rockfish and sablefish. All fishery-based analyses produced much larger estimates of abundance than bottom trawl surveys-indicative of the true catchability of survey trawls. Population trends from all analyses compared well except in canary rockfish, the species that presents the greatest challenge to obtaining reasonable precision and one that casts doubts on the usefulness of bottom trawl surveys for estimating its abundance. (PDF file contains 78 pages.)

Description of Early Larvae of Four Northern California Species of Rockfishes (Scorpaenidae: Sebastes) from Rearing Studies

About 72 species of Sebastes (Family Scorpaenidae) are found along the eastern Pacific coast of North America, some of which are heavily exploited by both commercial and sport fisheries. Because of the large number of species, the identification of early life stages has progressed slowly. The objectives of this study were 1) to rear the larvae of four species of rockfish (Sebastes mystinus, S. carnatus, S. atrovirens, and S. rastrelliger); and 2) to describe the larvae using morphometric measurements, pigmentation patterns, and head spination. Pigmentation was the most useful feature for identification purposes. Two general patterns were found: 1) a short row of ventral midline melanophores on the tail, and none or very little postero-dorsal pigmentation (S. mystinus); and 2) complete ventral midline pigmentation on the tail, and anterior and postero-dorsal melanophores (S. carnatus, S. atrovirens, and S. rastrelliger). With the exception of very early stages of S. carnatus and S. atrovirens, these species can be readily identified. Morphometric proportions and head spination did not show major differences among species. Because of the great similarities found among species in this genus, descriptions from field studies are uncertain to some extent. Laboratory rearings, although difficult, can at least provide early larvae from known species which allow precise identification as well as an estimation ofvariability of characters (e.g., pigmentation) within and between broods.(PDF file contains 22 pages.)

Control of California sea lion predation of winter-run steelhead at the Hiram M. Chittenden Locks, Seattle, December 1985-April 1986 with observations on sea lion abundance and distribution in Puget Sound

A study/predation control program was conducted at the Hiram M. Chittenden Locks in Seattle, Washington from 20 December through 23 April 1986. The principal objectives were to document the rate and effects of predation on winter-run steelhead (Salmo gairdneri Richardson) by California sea lions (Zalophus californianus); to control and minimize predation in order to increase the escapement of wild winter-runs to the Lake Washington watershed; to evaluate and recommend potential long term procedures for control of steelhead predation; and to document the abundance and distribution of California sea lions in Puget Sound.

Life history aspects of 19 rockfish species (Scorpaenidae: Sebastes) from the Southern California Bight

The authors investigated various life history aspects of 19 rockfish species (Sebastes chlorostictus, S. constellatus, S. dalli, S. elongatus, S. ensifer, S. entomelas, S. flavidus, S. goodei, S. hopkinsi, S. levis, S. melanostomus, S. miniatus, S. ovalis, S. paucispinis, S. rosaceus, S. rosenblatti, S. rufus, s. saxicola, S. semicinctus) from the southern California Bight. These aspects included depth distribution, age-length relationships (of 7 species), length-weight relationships, size at first maturity, spawning season, and fecundity. Growth rates of female S. elongatus, S. hopkinsi, S. ova/is, S. saxicola, and S. semicinctus were higher than male conspecifics. Multiple spawning per season was found in 12 species. Generally, most species spawned between late winter and early summer, though there was some spawning within the genus throughout the year. Spawning season duration ranged from 2 (S. flavidus) to 10 months (S. paucispinis). Spawning seasons tended to start earlier in the year and be of longer duration in the southern California Bight, compared to published data on central California conspecifics. Males matured at a smaller length in 7 of the 17 species studied. Maximum fecundities ranged from 18,000 (S. dalll) to about 2,680,000 (S. levis). (PDF file contains 44 pages.)