Incidental catch and mortality of striped bass, Morone saxatilis, in the commercial bay shrimp trawl fishery in the San Francisco estuarine complex

The commercial bay shrimp fishery was monitored from April 1989 to September 1990 in south San Francisco Bay, and from September 1989 to September 1990 in San Pablo Bay and Carquinez Strait, to estimate incidental catch and mortality of young-of-the-year (YOY), juvenile and adult striped bass. Of the total estimated by-catch of 44,000 to 52,000 YOY bass, 98.5% were taken in San Pablo Bay. Of the total estimated bycatch of 3160 to 3570 older bass, approximately 75% were taken in San Pablo Bay. Estimated mortality from shrimp tows was 22% for YOY and 2% for older bass. More than 99% of mortalities occurred in San Pablo Bay. July and August 1990, when YOYs were smallest and most vulnerable to trawling, was considered a critical period. A reduction in tow duration as well as effort in San Pablo Bay during this period may be effective in significantly reducing total mortality. (42pp.

Pacific herring, Clupea harengus pallasi, studies in San Francisco and Tomales Bays, April 1987 to March 1988

Herring schools were surveyed hydroacoustically and sampled in San Francisco Bay from late October 1987 to March 1988. Nine large schools (greater than 1000 tons) and four smaller ones were detected. Total acoustic biomass estimate, using a combination of echo integration and "visual integration" methods, was 71,110 tons. Improved acoustic calibration parameters resulted in this estimate being close to the spawn escapement-plus-catch estimate of 68,881 tons. However, the two biomass survey methods ere complementary and, when used together, provide a more accurate estimate of the spawning population than either method alone. Eighty-two samples, containing a total of 16,316 herring, were collected with variable-mesh gill net, midwater trawl, or obtained from the roundhaul fishery. Mean body length decreased by more then 20 mm from the beginning to the end of the spawning season. Sex ratios favored males in November and December, while females were more abundant in February and March. The 1982 through 1986 year classes (6- through 2-yr olds) contributed approximately 98% by weight and number to the total 1987-88 spawning biomass in San Francisco Bay. Herring year classes aged 7 and older each comprised no more then 1% of any school. Above average recruitment occurred for the 1986 year class. Recruitment may not be complete for some year classes until age 3 yr. This was particularly evident for the 1985 year clear. (72pp.

Pacific herring, Clupea harengus pallasi, studies in San Francisco Bay, Monterey Bay, and the Gulf of the Farallones, July 1982 to March 1983

Herring stocks were hydroacoustically surveyed and sampled in San Francisco Bay from November 1982 to March 1983. Twelve discrete herring schools were identified, all of which spawned between November 7 and February 23. One additional school was found in the Bay in March but showed no evidence of spawning. Total biomass estimate from hydroacoustic surveys was 67,040 tons. Based on MRR biomass estimates from spawned egg counts, an additional 10,000 tons may have spawned in November and December without being detected hydroacoustically. The largest schools occurred in January and February. Hydroacoustic estimates of biomass for individual schools during the season ranged from 270 to 22,300 tons. Sixty-seven samples, containing a total of 12,232 herring, were collected with variable mesh gill net and midwater trawl or obtained from the commercial roundhaul and gill net fisheries. In general, a trend was observed of decreasing mean size and age as the season progressed. Schools spawning in November and December consisted primarily of 4-, 5-, 6-, and 7-yr-old fish. Schools sampled from January to March were predominantly 2-, 3-, 4-, and 5-yr-old herring. The 1978, 1979, and 1980 yr classes (ages 5, 4, and 3 yr) were strong, comprising up to 90% of the samples. The 1981 yr class (2-yr olds) was relatively weak. Abundant rainfall and resultant low salinity in San Francisco Bay surface waters apparently delayed or prevented herring from spawning in February and March. A relationship may exist between relative abundance of young-of-the-year fish, as noted from midwater trawl samples collected by the Department's Bay-Delta Study, and the resultant year class strength of newly recruited 2-yr-old herring in San Francisco Bay's spawning stocks. (57pp.

Pacific herring, Clupea harengus pallasi, studies in San Francisco Bay, April 1986 to March 1987

Herring schools were surveyed hydroacoustically and sampled in San Francisco Bay from late October 1986 to March 1987. Eight large schools (greater than 1000 tons each) spawned from December to February and seven smaller schools were detected throughout the spawning season. Total acoustic biomass estimate using a "visual integration" technique was 40,930 tons, and it was determined from spawn escapement and commercial landings that an additional 2240 tons were not detected. This is a slight increase from last season's total of approximately 42,200 tons. For the first time, biomass was also estimated using echo integration equipment. A total biomass was obtained of 33,050 tons, including herring not detected acoustically. This estimate must be considered preliminary and subject to revision after target strength of San Francisco Bay herring is determined. Eighty-seven samples, containing a total of 13,125 herring, were collected with variable-mesh gill net and midwater trawl or obtained from the roundhaul and gill net fisheries. Mean body length (BL) of sampled herring decreased by about 20 mm from the beginning to the end of the spawning season. A combination of variable-mesh gill net and midwater trawl samples for a particular school closely approximates mean BL and age composition data from unbiased roundhaul samples. Age-weight and age-length relationships were average to above average compared with those of the previous two seasons. The 1982 year class exhibited unusually good growth, with a mean BL of 202.8 mm for herring aged from stratified random samples. The 1982 through 1985 year classes (5- through 2-yr olds) contributed 97% by number and 95% by weight to the total 1986-87 spawning biomass in San Francisco Bay. Good recruitment has occurred during the past four seasons. The weak 1981 year class contributed little to the total biomass as 6-yr olds. Average catch per tow of young-of-the-year (YOY) herring is a potential index of abundance for recruitment 18 months later as 2-yr olds. Estimated recruitment has only varied by 15% during the past three seasons and does not reflect the magnitude or trend in YOY catches in the bay. (85pp.

Pacific herring, Clupea harengus pallasi, experimental roe-on-kelp open pound fishery studies in San Francisco Bay, December 1987 to February 1988

The experimental open pound herring roe-on-kelp (ROK) fishery was studied in San Francisco Bay from mid December 1987 to mid February 1988. Five different harvests were observed and sampled. A total of 19.7 tons of Macrocystis sp. kelp covered with herring eggs was processed during this period. Kelp harvested from the Santa Barbara Channel Islands was transported to San Francisco Bay for hanging on the pounds. Weather conditions at the channel islands affected the condition and dimensions of the harvested kelp. Once suspended on the pounds in bay waters, the cut kelp deteriorated in 8 to 10 d. Based on our sampling, an average of 0.98 tons of kelp with a total blade surface area of 3031 m2 was suspended from each pound. ROK was sampled at the shoreside processing facility. Densities of attached eggs ranged from light (less than three layers) to heavy (more than six layers) for the five different spawns. Egg coverage on each pound also varied; kelp towards the middle portion of the pound received heavier deposition of eggs. Average weight increase from egg deposition, per blade, was 780% with the kelp weighing an average of 12.2% of the total. An average 13.2% by weight was trimmed during processing. A multiplication factor of 0.206 should be used to convert individual roe herring allotments to ROK allotments. Standard plastic totes containing processed ROK averaged 1783 lb total gross weight. Totes contained an average of 49.7% ROK by weight. Samples of roe-on-kelp increased an average of 10.9% in weight after brining during processing. (35pp.

Onboard sampling of the rockfish and lingcod commerical passenger fishing vessel industry in northern and central California, January through December 1993

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 primarily port-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 yellowtail rockfish 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 an increased availability of newly-recruited smaller, juvenile vermilion rockfish in observed catches. Total catch estimates were within values observed in previous years. (132pp.

Onboard sampling and the rockfish and lingcod commerical passenger fishing vessel industry in Northern and Central California, January through December 1994

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 237 CPFV 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 rockfishes together 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 blue rockfishes, 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 to increased 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.

Results of California Department of Fish and Game spot prawn trawl and trap fisheries bycatch observer program 2000-2001

In 1999 trap fishermen and environmental groups testified at a Fish and Game Commission (Commission) meeting that they were concerned about high levels of bycatch in the spot prawn trawl fishery. Environmental representatives requested that the Commission consider adopting regulations that would phase out the spot prawn trawl fishery by 2004 and convert spot prawn trawl permits to spot prawn trap permits. Also in 1999 the Department reported to the Commission the results of six observed spot prawn trawl tows in March 1999, including the ratio of weight of finfish bycatch to weight of spot prawns (7.4 to 1). Based primarily on the above factors, the Commission initially directed the Department to develop, as part of a package of regulatory proposals for the spot prawn trap and trawl fisheries, a proposal to phase out the spot prawn trawl fishery and convert trawl permits to trap permits. Subsequently the Department recommended that, instead of phasing out the spot prawn trawl fishery, information on the relative amount and type of bycatch in the trawl and trap fisheries be determined through an on-board observer program. An observer fee structure was proposed and adopted, and an observer program was in effect for all vessels landing spot prawns from July 14, 2000 to March 31, 2001. Vessels were required to purchase and possess a spot prawn observer fee permit in order to take and land spot prawns. Funds from the program were used to support on board observers and to digitize and analyze the data. Some fishing trips were observed after the requirement for the observer fee had expired. A total of 86 spot prawn trawl tows (71 from northern California-based vessels and 15 from southern California- based vessels) was observed on nine vessels during the period September 26, 2000 to September 19, 2001. Observed vessels fished from the ports of Fort Bragg, San Francisco, Monterey, Morro Bay, and Ventura. For northern California trawl vessels, the top five finfish species observed in the bycatch, in decreasing frequency of occurrence, were Pacific hake (whiting), Dover sole, sablefish, English sole, and splitnose rockfish, comprising 53.9% of all fishes by weight. Twenty-eight species of rockfishes were observed, comprising 28.1% by weight of all fishes. The weight ratio of total finfish bycatch to total spot prawn catch from all tows combined was 7.5 to 1. The ratio of total rockfish bycatch to total spot prawn catch was 2.1 to 1. For southern California trawl vessels, the top five finfish species observed in the bycatch, in decreasing frequency of occurrence, were Pacific sanddab, Pacific hake, slender sole, shortbelly rockfish, and Dover sole, comprising 83.1% of all fishes by weight. Fifteen species of rockfishes were observed, comprising 8.8% by weight of all fishes. The ratio of total finfish bycatch to total spot prawn catch from all tows combined was 17.7 to 1. The ratio of total rockfish bycatch to total spot prawn catch was 1.5 to 1. The ratio of total trawl bycatch, including invertebrates, to spot prawn catch was 8.8 to 1 in northern California and 20.6 to 1 in southern California. The National Marine Fisheries Service has determined the following rockfish species to be overfished and require rebuilding: bocaccio, canary, cowcod, darkblotched, widow, and yelloweye. Bocaccio, cowcod, darkblotched, and widow rockfishes were observed in multiple tows, and yelloweye and canary each were observed in a single tow. In general, the relative abundance of overfished rockfish species was low compared with other finfishes. However, expansions by weight of finfishes from observed tows to all spot prawn tows, based on the ratio of total to observed spot prawn landings, indicated that the estimated total bycatch of overfished rockfishes was significant in terms of allowable catch levels (optimum yields) established by the Pacific Fishery Management Council (Council). Other overfished species observed in the sampled catch including Pacific hake (whiting) and lingcod. Results from these trawl observations relative to bycatch levels were consistent with the few previous studies conducted. That is, the total observed bycatch in the trawl fishery was more than four times that of spot prawns by weight. A total of 27 trap vessels paid the required observer fee, and 23 of these landed spot prawns during the period in which the observer fee was required. Passage was secured on 16 of these 23 vessels for observations of bycatch. An additional vessel that had not paid the fee was sampled after the fee requirement period had expired. A total of 262 spot prawn trap strings (88 from northern California vessels and 174 from southern California vessels) was observed from 16 vessels during the study. Observed vessels fished out of the ports of Monterey, Morro Bay, Channel Islands Harbor, Ventura, Terminal Island, Newport Beach, Dana Point, Oceanside, and San Diego. For northern California trap vessels, the top five finfish species observed in the bycatch, in decreasing frequency of occurrence, were sablefish, rosethorn rockfish, greenblotched rockfish group, spotted cusk eel, and filetail catshark, comprising 77.7% of all fishes by weight. Seventeen species of rockfishes were observed, comprising 25.5% by weight of all fishes. The ratio of total finfish bycatch to total spot prawn catch from all strings combined was 0.15 to 1. The ratio of total rockfish bycatch to total spot prawn catch was 0.04 to 1. For southern California trap vessels, the top five finfish species observed in the bycatch, in decreasing frequency of occurrence, were lingcod, greenblotched rockfish group, threadfin sculpin, sablefish, and swell shark, comprising 66.4% of all fishes by weight. Twenty-two species of rockfishes were observed, comprising 32.5% by weight of all fishes. The ratio of total finfish bycatch to total spot prawn catch from all strings combined was 0.22 to 1. The ratio of total rockfish bycatch to total spot prawn catch was 0.07 to 1. The ratio of total trap bycatch, including invertebrates, to spot prawn catch was 1.0 to 1 in northern California and 2.0 to 1 in southern California. Most invertebrates and many fish species other than rockfishes could be returned to the water alive. Overfished rockfish species were observed infrequently, and expansions of observed bycatch data to all trap strings yielded relatively low total estimated bycatch weights for these species. In northern California, the relative amount of bycatch for all finfishes and rockfishes was 50 and 52 times greater, respectively, in the trawl fishery compared with the trap fishery. In southern California, the relative amount of bycatch for all fishes and rockfishes was 80 and 21 times greater, respectively, in the trawl fishery compared with the trap fishery. (Document has 88 pages

Onboard sampling of the rockfish and lingcod commerical passenger fishing vessel industry in northern and central California, January through December 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 fifth report in a series presents data collected in 1995, refers to historical data from 1987 to 1994, 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 12 ports, ranging from Fort Bragg in the north to Port San Luis (Avila Beach) in the south. Technicians observed a total of 1829 anglers fishing on 218 CPFV trips. These observed anglers caught 26,197 fish of which samplers determined 22,888 were kept. Over 62% of these fish were caught at Monterey or Morro Bay area ports. Only 18 of 55 species comprised at least one percent of the catch. The top ten species in order of abundance were yellowtail, blue, olive, and rosy rockfishes, lingcod, and canary, widow, gopher, starry, and vermilion rockfishes. Blue and yellowtail rockfishes together comprised approximately 47% of the observed catch. Overall, rockfishes represented 35 species or 64% of the 55 identified species. By number, rockfishes comprised 91.9 % of the observed catch. All CPUE and length data collected since 1987 were partitioned into six location groups for each port area, based on a combination of location, bottom depth, and distance from the nearest port. This allowed examination of indicator trends without potential biases due to non-random trip selection or ontogenetic changes in depth distribution for certain rockfishes. Results indicate that the two primary species in the northern and central California CPFV fishery, blue and yellowtail rockfishes (accounting for 47% of all observed fish in 1995), are in reasonably good condition with no steady declines in either average catch per angler hour or mean length during the last 8 years. The primary species of concern are mainly shallow-water species impacted by a recently expanded commercial hook-and-line fishery or deep-water species (chilipepper and bocaccio) which are fished intensively by the commercial industry and have experienced recent statewide stock declines. Estimated total rockfish catch, adjusted by logbook compliance rates and on board sampling data, has declined significantly in all port areas since 1992. This is largely attributable to increased recreational fishing effort for salmon as well as coast-wide stock declines in several important commercially fished species. (112pp.

Onboard sampling of the rockfish and lingcod commerical passenger fishing vessel industry in northern and central California, 1992

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 observed species 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 a lesser 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.