Pacific herring, Clupea pallasi, studies and fishery management in Tomales Bay 1992-93, with notes on Humboldt Bay and Crescent City area landings

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 was increased 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 for each 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 caught their 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.

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.

Pacific herring, Clupea pallasi, studies and fishery management in Tomales Bay, 1993-94, with notes on Humbolt and Crescent City area landings

The 1993-94 spawning biomass estimate for Pacific herring, Clupea pallasi, in Tomales Bay declined 40% from last season to 2,449 tons. Although this estimate is below the 20-year average of 4,700 tons, the spawning biomass estimate this year is close to the post 1982 El Nino 11-year average of 2,054 tons. The overall trend of increasing biomass since the 1989-90 season still continues. There were eight distinct spawns this season, the most in five years, with the largest spawn occurring in late January. A total of 3.5 million m2 of eelgrass, Zostera marina, was measured in Tomales Bay this season. Eelgrass density increased in the majority of the beds. The commercial gillnet fleet in Tomales Bay caught a total of 219 tons of herring this season yielding an exploitation rate of 8.9%. Herring aged four, five, and six comprised 90% by number of this season's commercial gill net catch. Mean weight of herring ages three, six, and seven decreased slightly over last season while increases were seen for ages four, five, and eight. Mean length of commercial caught herring increased slightly over 1992-93. Department variable-mesh gill nets caught a total of 455 herring of which 232 were aged. The dominant age class was four-yr-olds comprising 27% of the sample by number, followed by six-yr-olds representing the highly successful 1988 year class. In Humboldt Bay, the 1993-94 commercial catch of 62.8 tons was about 5% over the 1993-94 season quota of 60 tons and was well above Humboldt Bay's 21-year average catch of 40.4 tons. Crescent City area herring fishermen caught 32.5 tons, approximately 2% over the season quota for the Crescent City area. The 1993-94 season commercial catch is well above the 20-year average of 23.7 tons for this area. (31pp.

Biomass estimates of Pacific herring, Clupea pallasi, in California from the 1991-92 spawning-ground surveys

The spawning biomass of Pacific herring, Clupea pallasi, estimated from spawning-ground surveys in San Francisco Bay declined to 41,000 tons this season. This was the second consecutive year that the San Francisco Bay herring population estimate has declined. In Tomales Bay, the 1991-92 season spawning biomass estimate, including the catch of 24 tons from Bodega Bay, was 1,238 tons. This was the third consecutive season that the Tomales-Bodega area herring population has increased. The 1991-92 Humboldt Bay herring spawning biomass estimate of 225 tons, was nearly half of last season's estimate of 400 tons. December and January were the peak months of spawning activity in all areas surveyed. In San Francisco Bay, the first major spawn since the 1981-82 season occurred in the Sausalito area, and the Oakland-Alameda area accounted for 50% of all spawning activity. A total of 3.5 million m2 of eelgrass, Zostera marina, was measured in Tomales Bay this season. The eelgrass density declined in most beds this season. (46p.

Biological characteristics of the catch from the 1991-92 Pacific herring, Clupea pallasi, roe fishery in San Francisco Bay and Tomales Bay

The Tomales-Bodega Bay catch during the past two seasons has been from the northern part of outer Bodega Bay, due to the closure of the Tomales Bay fishery. In the Tomales-Bodega Bay area, 4-, 5-, and 6-yr-old herring, Clupea pallasi, comprised 84% by number of the 1991-92 season's gill net catch. The number of 4-yr-olds increased to 26% of the gill net catch, the second consecutive year that the percentage of 4yr-olds has increased. Four-yr-olds are completely recruited into the gill net fishery, and thus are a good indicator of relative year class strength. Average length of herring in the Tomales-Bodega Bay area gill net catch decreased due to a shift to younger herring in the catch. Herring age and size data obtained from Tomales Bay with a variable-mesh research gill net were similar to data from San Francisco Bay obtained with the same net. Herring over 7-yrs-old were absent from the Tomales Bay variable-mesh gill net and the outer Bodega Bay commercial gill net samples. In San Francisco Bay, the age composition of the gill net catch was again 4-, 5-, and 6-yr-old herring, which comprised 87% of the catch. In the round haul fishery, 3and 4-yr-old herring dominated, comprising 63% of the catch. Recruitment of 2-yr-old herring was poor. The average length of herring in the San Francisco Bay gill net catch was the lowest on record, 189 mm body length (BL). The average length of herring in the round haul catch increased to 179 mmBl due to poor recruitment of young herring. (25pp.

An atom-efficient and convergent approach to the preparation of NS5A inhibitors by C-H activation

A novel approach of the convergent functionalisation of aryl dibromides to form NS5A type inhibitors using C–H activation is reported. The focus of investigation was to reduce the formation of homodimeric side product, as well as to investigate the scope of different aryl dibromides that were tolerated under the reaction conditions. The C–H activation methodology was found to give a viable synthetic route to NS5A inhibitors, with late stage functionalisation of the core portion of the molecule, albeit with some chemical functionalities not tolerated