Recent Submissions

  • Biological surveys of five southern artificial reefs: Oceanside #1, Oceanside #2, Carlsbad, Pacific Beach, and Mission Bay

    Bedford, Dennis; Kashiwada, Jerry; Walls, Greg (California Department of Fish and GameLong Beach, CA, 1995)
    (Document pdf contains 19 pages)
  • Sea Otter, Enhydra lutris, mortalities in California, 1968 through 1993

    Pattison, Christine A.; Harris, Michael D.; Wendell, Frederick E. (California Department of Fish and Game Marine Resources DivisonMorro Park, CA, 1997)
    Sea otter, Enhydra lutris, mortality in California and the relative contribution from specific causes was assessed for the 26 years from 1968 through 1993. There were 2,082 dead sea otters recorded from Tomales Bay (Marin County) south to Bluff Cove (Los Angeles County) during that period. The average number of carcasses recorded was 80 per year and seven per month. Sex was identified in 87% (n=1,819) of the cases and was composed of 47% female and 53% male. A relative age was assigned to 97% (n=2,017) of the cases and was composed of 28% pup, 18% subadult and 54% adult.Specific causes of death were determined for 26% (n=55 1) of the cases. The majority of these (n=381) were considered to be due to natural causes and included the following specific causes: shark bitten (n=78), probably shark bitten (n=106), other natural causes (n=140), and mating wounds (n=57). The remaining (n=170) were considered to be due to human-related causes and included the following specific causes: shot(n=72), probably shot (n=8), net drowned (n=76), and other human causes (n=14).The large proportion of carcasses without an identified specific cause of death prompted a more detailed necropsy effort in 1992 and 1993. During that period, 78 of the 232 recovered carcasses were examined by veterinary pathologists and a specific cause of death was determined in 76% (n=59) of the cases. This effort identified a wide range of specific causes of death that otherwise may have been categorized as "unknown without trauma". Considering the variety of diseases diagnosed in this expanded necropsy program, it would be prudent to continue this level of examination to refine our knowledge of sea otter pathology. (48pp.)
  • Southern California fisheries monitoring summary for 1993 and 1994

    McKee-Lewis, Kimberly K.; Read, Robert B. (California Department of Fish and Game Marine Resources DivisonSan Diego, CA, 1997)
    The southern California Monitoring and Management Units collectively gathered 803 discrete samples of 7,329 marine finfishes and invertebrates from local commercial fishmarkets or authorized fish transporters in 1993. Nineteen different species were sampled and biological information recorded for future summarization and use in formulating fisheries management strategies and decisions. Increased sampling efforts in 1994 resulted in 801 samples of 14,566 marine finfish and invertebrates representing 44 different species. Fisheries trends and threats to local fishing opportunities were identified. Results of Marine Recreational Fishery Statistics Survey interviews were also incorporated for a more complete overview of species targeted by both the sport and commercial industries. (26pp.)
  • Status of the Pacific Mackerel resource during 1996 management recommendations for the fishery

    Barnes, J. Thomas; Yaremko, Marci; Bishop, Traci (California Department of Fish and Game Marine Resources DivisonLa Jolla, CA, 1997)
    The California fishery for Pacific mackerel (Scomber japonicus) has declined precipitously since 1990. Statewide landings during 1995 continued the downward trend, and totaled only 9,185 short tons. During the last few years, the principal cause of reduced catches has been lowbiomass and poor availability on the traditional fishing grounds in southern California waters. Cannery closures since 1993 may have also affected demand.Several sources of information are available on the status of the Pacific mackerel stock, all of which suggest a decline in stock biomass compared to the late 1970's and 1980's. Landing statistics, available since 1978 for both the U.S. and Mexican fisheries, show reduced catchesduring recent years. Catch rates for the southern California Commercial Passenger Fishing Vessel (CPFV) fleet have also shown declining trends since the 1970's. Other fishery- independent data from spotter pilot aerial observations and California Cooperative Oceanic Fisheries Investigations (CalCOFI) ichthyoplankton surveys indicate lower abundance compared to the early 1980's.We used a tuned virtual population analysis (VPA) model called ADEPT to estimate Pacific mackerel biomass. The model finds the best statistical fit between fishery-based, age-structured biomass estimates and other data from aerial observations, plankton surveys, CPFV catch data, and a spawner-recruit relation. Based on the estimated number of fish in each year class during the last quarter of 1995 (including the 1995 year class), and using certain assumptions for expected fishing mortality during the first half of 1996, we project that the Pacific mackerel biomass will be 52,000 tons at the beginning of the 1996/97 fishing season, on July 1,1996. There is a large degree of uncertainty in our 1996 biomass estimate because the 1995 year class (fish of age one) comprises most of the biomass.The Fish and Game Code specifies that when the biomass is between 20,000 and 150,000 tons, the season's quota shall be 30 percent of the total biomass in excess of 20,000 tons. Using that formula and our projection for July 1,1996, we recommend a commercial fishery quota of 9,600 tons for the 1996/97 fishing season. (26pp.)
  • Pacific Herring, Clupea pallasi, spawning population assessment for San Francisco Bay, 1992-93

    Watters, Diana L.; Oda, Kenneth T. (California Department of Fish and Game Marine Resources DivisonMenlo Park, CA, 1997)
    We conducted hydroacoustic surveys, spawn surveys, and sampled schools and fishery landings from 8 November 1992 through 18 March 1993 to assess the status of San FranciscoBay's Pacific herring spawning population. Our spawning biomass estimate of 21,186 tons is the lowest since 1978 when subtidal spawns were included in estimates; it alsorepresents a third consecutive season of decline. The principal reason for this very low estimate is a lack of two-, three-, and four-year-old herring in the spawning population from the 1991,1990, and 1989 year-classes. Although four-year-olds were the most abundant cohort, their actual number was very low. Five-year-olds from the highly successful 1988 year-class were the second most abundant cohort.Warm-water conditions and poor upwelling associated with the 1991-92 El Nino are likely causes of the low spawning biomass, although adverse impacts on the condition andgrowth of spawners were not apparent. Warm water may have displaced herring to the north of San Francisco Bay.We also continued to collect data for a herring young-of-the-year abundance index during April, May, and June of 1993. The index was low for the 1990 and 1991 year-classes, but high for the 1989 year-class. The 1989 and 1990 year-classes appear poor; however, the success of the 1991 year-class will not be known until next season when it fully recruits to the spawning population.The index for the 1992 year-class is relatively low as is the index for 1993.The season's 5,555-ton quota (based on the previous season's biomass estimate) exceeded our harvest goal of no more than 20% of spawning biomass for the first time since the 1970s. The number of three-year-old fish in gill net catches increased substantially this season, possibly indicating the use of smaller mesh.Because of the extremely low spawning biomass and uncertainty about future recruitment, our recommendation to the Fish and Game Commission was to close the herring roefishery in San Francisco Bay until the season following a spawning biomass estimate of 26,000 tons. (30pp.)
  • Onboard sampling and the rockfish and lingcod commerical passenger fishing vessel industry in Northern and Central California, January through December 1994

    Wilson-Vandenberg, Deb; Reilly, Paul N.; Wilson, Carrie E. (California Department of Fish and Game Marine Resources DivisionMonterey, CA, 1996)
    The Central California Marine Sport Fish Project has been collecting angler catch data on board Commercial Passenger Fishing Vessels (CPFVs) fishing for rockfish or lingcod since 1987. The program depends on the voluntary cooperation of CPFV owners and operators. This fourth report in a series presents data collected in 1994, refers to historical data from 1987 to 1993, and documents trends in species composition, angler effort, catch per unit effort (CPUE), and, for selected species, mean length and length frequency.Angler catches on board central and northern California CPFVs were sampled from 14 ports, ranging from Crescent City in the north to Port San Luis (Avila Beach) in the south. Technicians observed a total of 2053 anglers fishing on 237CPFV trips. These observed anglers caught 24,731 fish of which samplers determined 22,615 were kept. Over 63% of these fish were caught at Monterey or Morro Bay area ports.Only 18 of the 53 species each comprised at least one percent of the catch. The top ten species in order of abundance were blue, yellowtail, rosy, chilipepper, canary, and black rockfishes, lingcod, and widow, starry and greenspotted rockfishes. Blue and yellowtail rockfishestogether comprised approximately 44% of the observed catch. Overall, rockfishes represented 32 species or 60% of the 53 identified species.In general, 1994 data showed continued evidence of sustainability of the CPFV rockfish fishery with a few exceptions for some species in each port area sampled. We identified areas of concern for three nearshore species (black, blue, and brown rockfishes), three offshore species(bocaccio, chilipepper, and widow rockfish), and two wide-depth range species (canary and yelloweye rockfishes). Declining trends in CPAH in at least one port area were identified for each of these species except black and bluerockfishes, some of which may be related to natural variability in year class strength or stock movement. Mean length decreased in at least one port area for black, blue, brown, and canary rockfishes and chilipepper, although for black rockfish and chilipepper this was attributed toincreased recruitment of juveniles.Positive trends identified included increased CPAH for black rockfish in the San Francisco and Monterey areas, for canary rockfish in the San Francisco area, and for brown rockfish in the Morro Bay area.Total northern and central California CPFV catch estimates, based on logbook data and adjusted by sampling data and compliance rates, indicated that port area-specific decreases have occurred since 1988 for yellowtail rockfish and lingcod (San Francisco), chilipepper (Monterey),and blue rockfish (Monterey and Morro Bay).The competing influences of the nearshore commercial hook-and-line fishery were apparent when comparing relative species composition to that of the CPFV fishery. Declines in CPAH in the CPFV fishery for some shallow water species, such as brown rockfish in the Bodega Bay area, may be related to increased commercial fishing effort. (98pp.)
  • Sea otter, Enhydra lutris, containment management: field studies and feasibility assessment

    Wendell, Fred; Pattison, Christine; Harris, Michael (California Department of Fish and Game Marine Resources DivisionMorro Bay, CA, 1996)
    Limiting sea otter geographic distribution in California (containment management) has long been recognized as being necessary to preserve human recreational and commercialuses of shellfish resources. However, passage of federal legislation that focused preferentially on marine mammal protection and the 1977 listing of the California sea otter population as "threatened" effectively precluded any range-limiting management program.Research, however, that evaluated various non-lethal means of influencing sea otter movements and distribution was encouraged. Our research suggests that herding and acoustical devices may not have any real potential use in this context. Based on research-related capture success rates, capture and relocation techniques may be useful in influencing sea otter geographical distribution.The translocation of sea otters to San Nicolas Island provided the first opportunity to test the technical feasibility of maintaining a large area free of sea otters. Capture success rates were appreciably poorer than those achieved during research-related efforts. We identifyseveral logistical and behavioral influences that contributed to the relatively poor success rate. Based on this evaluation, we discuss the factors likely to limit application of these techniques in the future.We feel that capture techniques can be useful in a long-term management program, if used in conjunction with efforts to limit the sea otter population growth rate. Consequently, wefeel future research should focus on assessing individual health effects from using chemical contraceptives and assessing the feasibility of their use to safely control population growth. (12pp.)
  • Early life-history studies of nearshore rockfishes and lingcod off Central California, 1987-92

    VenTresca, David A.; Houk, James L.; Paddack, Michelle J.; Gingras, Marty L. (California Department of Fish and Game Marine Resources DivisionMonterey, CA, 1996)
    This study focused on the physical and biological processes that influence the distribution, abundance, growth, and survival of young-of-the-year (YOY) rockfishes and lingcod along the central California coast. The annual somatic and reproductive condition of adult female blue rockfish corresponded to annual upwelling. Resulting larval production may correspond to the reproductive potential of adults; however, ultimate recruitment success of YOY is also effected by oceanographic conditions during their planktonic stage. Within a year, each species of settled YOY was observed concurrently and in relatively similar abundances at all study dive sites along the central coast. Most species of YOY exhibited similar growth patterns amongstations and years. We found a high degree of interannual variability in the condition of adults and relativeabundances of YOY. We believe a large part of this variability is due to annual oceanographic conditions,specifically upwelling.Marine reserves, which would protect populations of reproductively mature rockfishes and lingcod and insure 1arval production, have been suggested as an alternative to present management strategies for these species. However, a crucial question is whether or not larvae from adult fish in reserves would significantly contribute to replenishing stocks in other areas. This study was undertaken to assist in determining the feasibility of reserves to enhance nearshore rockfish and lingcod populations. (78pp.)
  • Biological surveys of Santa Monica Bay artificial reef and Topanga artificial reef

    Bedford, Dennis; Kashiwada, Jerry; Walls, Greg (California Department of Fish and Game Marine Resources DivisionLong Beach, CA, 1996)
    This report details the development of the biological communities on 2 artificial reefs off southern California (Figure 1). Santa Monica Bay Artificial Reef(SMBAR) andTopanga Artificial Reef(TAR) were both constructed in 1987 with 20,000 and 10,000 tons of quarry rock respectively.SMBAR was constructed in the manner of replication reefs which were designed by researchers to study the effects ofenvironmental and structural variables on reef productivity in situ and TAR was built to promote kelp habitat. SMBAR iscomposed of 24 module pairs of varying height and rock size arranged along three depth strata while TAR was built in 3 piles along one depth strata (Table 1, Figure 2 & Figure 3).SMBAR is located at 34°00'47''N; 118°32'33" W approximately 5 nautical miles from the Marina del Rey entrance along a course of 290° magnetic. TAR is located at 34°01'38.10" N; 118°31'54.80"W; approximately 5.25 nautical miles from theMarina del Rey entrance along a course of302° magnetic.The modules of SMBAR cover 3.58 acres of the 256 acres allotted in the permit. Each module has a footprint of about 0.07 acres. The modules of TAR cover 2 acres of 13 acres allotted in the permit. Each module has a footprint of about 0.70 acres.During the late fall of 1995 both reefs were surveyed by Department divers to assess how closely their biological communities had progressed towards a stable "equilibrium"community. Due to the relatively young age of the reefs and the rapid successional change which occurs in the associated biotic communities of new reefs (Carlisle et al. 1964; Turneretal. 1969; Carteretal. 1985; Matthews 1985; Solonsky 1985; Ambrose and Swarbrick 1989; Anderson et al. 1989;Hueckel and Buckley 1989; and WIlson et al. 1990), only qualitative surveys were conducted. (17pp.)
  • Status of the Pacific sardine (Sardinops sagax) resource and fishery

    Barnes, J. Thomas; Yaremko, Marci; Hanan, Doyle (California Department of Fish and Game, Marine Resources DivisionLa Jolla, A, 1996)
    California Fish and Game Code states that the annual sardine quota can be set at a level greater than 1,000 tons, providing that the level of take allows for continued increase in the spawning population. The primary goal of management as directed by the Code is rehabilitation of theresource, with an added objective of maximizing the sustained harvest.We estimate the sardine population size to have been 353,000 short tons on July 1, 1995. Our estimate was based on output from an integrated stock assessment model called CANSAR(Deriso 1993). CANSAR is a forward-casting age-structured analysis using fishery-dependent and fishery-independent data to obtain annual estimates of sardine abundance, year-class strength and age specific fishing mortality for 1983 through the first semester of 1995. CANSAR couples asimulation model with sardine population dynamics. Non-linear least-squares criteria are used to tune the model to match catch-at-age data and other indices of sardine abundance.To calculate the 1996 fishery quota, we used the harvest formula selected as the preferred option in the draft Coastal Pelagic Species-Fishery Management Plan (CPS-FMP). That formula has undergone extensive scientific and user-group review as part of the Pacific Fishery Management Council's (PFMC) CPS-FMP adoption process and has the endorsement of the fishing industry and the scientific community. Use of this formula will result in a reduced fishing mortality rate compared to the formula used to calculate the quota in 1995. We conclude that it isparticularly important to reduce fishing mortality for 1996 because the rates may have been excessive in recent years, especially for older aged sardines.Accordingly, we recommend a 1996 sardine harvest quota of 35,000 short tons. (21pp.)
  • Status of the Pacific mackerel resource and fishery 1994 and 1995

    Barnes, J. Thomas; Hanan, Doyle A. (California Department of Fish and Game Marine Resources DivisonLa Jolla, CA, 1995)
    The California fishery for Pacific mackerel, Scomber japonicus, has declined precipitously since 1990, and statewide landings during 1994 totaled only 11,070 short tons. The principal cause of the low catches has been low biomass and poor availability on the traditional fishinggrounds in southern California waters.Several sources of information are available on the status of the Pacific mackerel stock. Landing statistics were available since 1978 for both the U.S. and Mexican fisheries, and both fisheries show similar declines during recent years. Other fishery-independent data from aerialobservations and plankton surveys (mackerel larvae samples) also show declines in abundance compared to the early 1980's.We used a tuned virtual population analysis (VPA) model called ADEPT to estimate Pacific mackerel abundance. The model finds the best statistical fit between fishery-based age-structured biomass estimates and other data from the aerial observations and the plankton surveys. A model-derived biomass estimate for July 1, 1994 was 71,000 tons. Based on the estimated number of fish in each year class at the end of 1994, and using certain assumptionsconcerning expected fishing mortality during the first half of 1995, we project that the Pacific mackerel biomass will be 56,000 tons at the beginning of the 1995/96 fishing season, on July 1, 1995.The Fish and Game Code specifies that when the biomass is between 20,000 and 150,000 tons, the season's quota shall be 30 percent of the biomass in excess of 20,000 tons. Using that formula and our projection for July 1, 1995, the commercial fishery quota for the 1995/96 fishing season is 10,800 tons.(21pp.)
  • Compensation of displaced gill netters pursuant to proposition 132

    Barnes, J. Thomas (California Department of Fish and Game, Marine Resources DivisionLa Jolla, A, 1995)
    Proposition 132, also known as "The Marine Resources Protection Act", was passed by the California electorate in November 1990. One of the purposes of the Act was to prohibit the use of gill nets in an area referred to as the "Marine Resources Protection Zone" or MRPZ, which is roughly equivalent to all State waters south of Point Arguello, with some important exceptions such as additional fishing depth restrictions in the Los Angeles/Orange County area, and alsoaround the Channel Islands. The Act instructed the Department to compensate displaced gill net fishermen for the loss of their fishery. Payment of compensation was contingent upon each applicant meeting certain conditions that were specified in the Act.Out of the original 136 applicants, the Department identified 86 who met all the requirements for further processing of their claims. The Act dictated that qualified claimants were entitled to compensation in an amount equal to the average annual value of their gill net catches (excluding rockfish) from within the area now closed to gill nets (the MRPZ), during the period of 1983 to 1987. Based upon our historical landing receipt and logbook databases, the Department reconstructed the past fishing activities of those qualified claimants. Data available to the Department were not originally intended to address the specific eligibility criteria that were specified in the Act, but we were able to calculate the amount of each claimant's compensation by using the fish receipt data to determine what each claimant caught (and the value), and the logbook data to determine where he/she caught it. The combined total amount of compensation paid the 86 claimants was $1.2 million.This report describes the Department's activities with respect to the processing of claims and payment of compensation to displaced gill net fishermen. (19pp.)
  • Onboard sampling of the rockfish and lingcod commerical passenger fishing vessel industry in northern and central California, 1992

    Wilson, Carrie E.; Halko, Laura A.; Wilson-Vandenberg, Deb; Reilly, Paul N. (California Department of Fish and Game Marine Resources DivisionMonterey, CA, 1996)
    In 1992 fishery technicians sampled 230 commercial passenger fishing vessel (CPFV) trips targeting rockfish and lingcod from the port areas of Fort Bragg, Bodega Bay, San Francisco, Monterey, and Morro Bay. The skippers of 44 vessels, and 2,190 anglers, cooperated in the study. Species composition by port area and month, catch-per-unit-effort, mean length, and length frequency of lingcod and the 18 most frequently observed rockfish species are presented, as well as fishing effort relative to time, depth, and distance from port. Total catch estimates based on unadjusted and adjusted logbook records are summarized.Average catch of kept fish per angler day was 12.6 and average catch of kept fish per angler hour was 4.0. A continuing trend of an increasing frequency of trips to deep (> 40 fm) locations was observed in the Bodega Bay, San Francisco, and Monterey areas. Bodega Bay and San Francisco showed the highest frequency of trips to distant locations.Sixty species comprised of 29,731 fish were observed caught during the study. Rockfish comprised 93.5% by number of the total observed catch. The five most frequently observedspecies were blue, yellowtail, widow and rosy rockfishes, and bocaccio, with lingcod ranking eighth.CPFV angler success, as determined by catch per angler hour, generally increased in all ports in 1992 compared to previous 1988-91 data (Reilly et al. 1993). However, port-specific areas of major concern were identified for chilipepper, lingcod, and black rockfish, and to alesser extent brown, canary, vermilion, yelloweye, widow and greenspotted rockfishes. These areas of concern included steadily declining catch rate, steadily declining mean length, and/or a high percentage of sexually immature fish in the sampled catch.Recent sampling of the commercial hook-and-line fishery in northern and central California indicates that most rockfishes taken by CPFV anglers are also harvested commercially. (105pp.)
  • Onboard sampling of the rockfish and lingcod commerical passenger fishing vessel industry in northern and central California, January through December 1993

    Wilson-Vandenberg, Deb; Reilly, Paul N.; Halko, Laura (California Department of Fish and Game Marine Resources DivisionMonterey, CA, 1995)
    The Central California Marine Sport Fish Project has been collecting angler catch data on board Commercial Passenger Fishing Vessels (CPFVs) fishing for rockfish or lingcod since 1987. The program depends on the voluntary cooperation of CPFV owners and operators. This third report in a series presents data collected in 1993, refers to historical data from 1987 to 1992, and documents trends in species composition, angler effort, catch per unit effort (CPUE), and, for selected species, mean length and length frequency.Angler catches on board central and northern California CPFVs were sampled from 15 ports, ranging from Crescent City in the north to Port San Luis (Avila Beach) in the south.Technicians observed a total of 2385 anglers fishing on 248 CPFV trips. These observed anglers caught 29,622 fish of which Technicians determined 27,421 were kept. Over 60% of these fish were caught at Monterey or Morro Bay area ports. Only 18 of the 58 species each comprised at least one percent of the catch. The top ten species in order of abundance were blue, yellowtail, chilipepper, rosy, widow, canary, greenspotted, bocaccio, and vermilion rockfishes and lingcod. Blue and yellowtail rockfishes, and chilipepper, together comprised over 50% of the observed catch. Overall, rockfishes represented 35 species or 59% of the 58 identified species.In general, 1993 data indicated that in all port areas CPFV fishery resources, with a few exceptions, were in a viable and sustainable condition, similar to the previous 6 years. This study identified nine species, lingcod and eight rockfishes, with areas of concern which were primarilyport-specific. Six of these ranked among the 10 most frequently observed species, five were schooling or migratory species, two were nearshore species, and three were offshore species. Trends of most concern continue to be declining catch per angler hour (CPAH) - of yellowtailrockfish in the Bodega Bay area, lingcod in shallow locations near the Monterey area, and yelloweye rockfish in the San Francisco area, as well as decreasing mean lengths of canary rockfish in the Monterey area and brown rockfish in the Morro Bay area. Populations of black rockfish, the species presently of greatest concern in the CPFV fishery, showed some positive signs this year. Also on the positive side, the Monterey and Morro Bay areas experienced anincreased availability of newly-recruited smaller, juvenile vermilion rockfish in observed catches. Total catch estimates were within values observed in previous years. (132pp.)
  • Pacific herring, Clupea pallasi, studies and fishery management in Tomales Bay 1992-93, with notes on Humboldt Bay and Crescent City area landings

    Moore, Thomas O.; Mello, John J. (California Department of Fish and Game Marine Resources DivisonBodega Bay, CA, 1995)
    The 1992-93 spawning biomass estimate for Pacific herring, Clupea pallasi, in Tomales Bay increased for the fourth year in a row to 4,078 tons. This is the highest estimate since the 1986-87 season. The December spawning biomass total of 1,346 tons was the second highest December escapement total since surveys began in 1972-73.A total of 3.58 million m2 of eelgrass, Zostera marina, was measured in Tomales Bay this season. Eelgrass density increased in the majority of beds.The commercial catch of 222 tons was taken entirely from Tomales Bay since outer Bodega Bay was closed to herring fishing during the season. Gill net mesh size wasincreased to 2.125 inches from 2.0 inches this season. Herring aged 4,5, and 6 comprised 92% by number of the season's herring catch. Mean weight of herring foreach age decreased while mean length for all ages combined increased slightly.Tomales Bay herring samples indicated that older year-classes, missing in commercial catch samples, were present prior to the January start of the commercial fishery. The abundance of 4-yr-old herring was low in samples from variable-mesh and commercial gill nets, indicating less than average recruitment of the 1989 year-class.In Humboldt Bay the 1992-93 season commercial herring catch totalled 28.6 tons, less than half of the 60-ton quota. Crescent City area herring fishermen nearly caughttheir 30-ton quota with a total of 28.5 tons landed. No spawning biomass estimate is available for the 1992-93 season for either area. (29pp.)
  • Relative abundance and size composition of subtidal abalone, Haliotis spp., sea urchin, Strongylocentrotus spp., and abundance of sea stars off Fitzgerald marine reserve, September 1993

    Karpov, Konstantin A.; Geibel, John J.; Law, Philip M. (California Department of Fish and Game Marine Resources DivisonFort Bragg, CA, 1997)
    Data were collected at twenty-six dive stations at seven discrete latitudes along Fitzgerald Marine Reserve (FMR). Dive stations were targeted at three stratified depth zones: shallow (6.1 m), medium (10.7 m), and deep (16.8 m) in six of the seven locations. Two types of linetransects, emergent and invasive, were completed by separate dive teams at each dive station. The area surveyed totalled 1,510 m2 for emergent and 560 m2 for invasive transects.Reef habitat dominated all depth zones, with moveable boulder and cobble increasing at medium and shallow depths. Encrusting coraline and surface algae dominated (49%), followed by turf (37%), sub-canopy (11.2%), and rare canopy (0.2%). Canopy was found only at shallow depths. Turf and sub-canopy decreased with depth.Only two species of abalone, red, Haliotis rufescens, and flat, H. walallensis, were found. Flat abalone were extremely rare with only two found on invasive transects (0.004 abalone m-2). Red abalone densities were low at both emergent (0.02 abalone m-2, s.e.=O.Ol) andinvasive (0.07 abalone m-2, s.e.=0.03 ) transects. Red abalone concentrations differed significantly by depth and location. No abalone were found at deep depths and only onesport-legal (178 mm shell length) abalone was found at medium depth. One commercial legal (198 mm shell length) abalone was found on the entire survey. Most sport-legal abalone were located in cryptic habitat in shallow invasive transects (38%), compared to 7% on emergent transects. The only evidence of recruitment was found on invasive transects where three young-of-the-year (<=31 mm shell length) red abalone were found. Evidence from our survey and other sources suggests that sport and commercial fisheries are not sustainable off the San Mateo coast.Red urchin, Stongylocentrotus franciscanus, were more abundant than purple urchin, S. purpuratus, or red abalone. Red urchin densities were lower in emergent (1.08 urchin m-2,s.e.=0.04) than invasive (1.52, s.e.=0.06 m-2) transects. Densities of red urchin at deep stations in areas of lower algal abundance and potentially greater commercial fishing pressure were about one-half the densities at medium and shallow depths. ANOVA showed significant differences by depth and location. Mean Test Diameter (MTD) increased from deep to medium to shallow depths, while juvenile (<=50 mm) MTD showed an inverserelationship with depth. Shallow-depth invasive transects revealed a missing mode of 83 mm red urchin. This size mode was not found in emergent transects, probably due to cryptic habitat.Purple urchin were found at low densities at all three depth strata. Purple urchin densities were comparable in emergent (0.11 urchin m-2, s.e.=0.02 ) and invasive (0.09 urchin m-2,s.e.=0.03) transects. ANOVA showed densities varied significantly by location but not depth. 'Juvenile' purple urchin abundance showed an inverse relation to juvenile red urchin, increasing from deep to shallow depths. Purple urchin MTD of 84 mm (s.d.=23) was largerthan reported for intertidal areas off FMR.Sea stars were found in high abundance off FMR. Bat stars, Asterina minata, had the highest densities (0.79 sea stars m-2, s.e.=0.03) followed by Pisaster sp. (0.47 sea stars m-2,s.e.=0.03 ), and sunflower stars, Pycnopodia helianthoides, (0.11 sea stars m-2, s.e.=0.04).Pisaster sp. was the only group of sea stars where differences in density were significant by depth or location. (30pp.)