Cruise Report 72-KB-18: Pacific Mackerel Survey

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Status of the Jack Mackerel resource and its management

The jack mackerel, Trachurus symmetricus, resource off the west coast of North America is known to be large and widely distributed. The spawning biomass is estimated to be 2.1 to 4.8 million tons based upon abundance of jack mackerel eggs collected at sea. The distribution extends from the Gulf of Alaska to the Gulf of Tehuantepec, off the coast of southern Mexico, and as far as 1,500 miles seaward. Within this range lies an area of maximum density which extends from Point Conception to central Baja California. Jack mackerel biological data has not been processed very rapidly due to higher priorities for analysis of sardine and Pacific mackerel data, and the apparent healthy condition of this resource. The California Department of Fish and Game initiated several projects in 1972 to resolve unanswered biological questions. (14pp.

Maturation and growth of Pacific Mackerel, Scomber japonicus Houttuyn

The maturation of Pacific mackerel has never been documented clearly. Analysis of data reveals spawning can occur from March through October, but the majority takes place from April through August. During this April through August period, 22.5%, 65.7%, 75.1%, 84.7%, 84.2%, and 87.5% of the female fish were mature or maturing for Age Groups I, II, III, IV, V, and VI+ respectively. A von Berta1anffy growth curve and a weight-length curve were calculated. The weight-length curve was found to differ significantly from a curve previously published. (21pp.

Status of Pacific mackerel spawning population, 1975

Three methods were used to determine the Pacific mackerel population. The tag and recovery method estimated the population at 620 short tons. The other two estimates were based on regression techniques of partyboat catches and these results yielded 2,921 tons and 1,385 tons, respectively. All three estimates were below the 10,000 tons prescribed for a fishery and thus no harvest could be allowed. (14pp.

Status of Pacific Mackerel spawning population, 1973

This is the first annual report of the status of the spawning population of the Pacific mackerel as required by Section 8388.3 of the Fish and Game Code. During 1972 and early 1973, several methods of determining population size were investigated as mechanisms for estimating the spawning population size of Pacific mackerel stocks north of Punta Eugenia, Baja California, and a method using tagging procedures proved to be the most acceptable. The estimate of the Pacific mackerel spawning population obtained by tagging procedures was 5,480 tons. This estimate agrees generally with those obtained from alternate methods in which previously computed spawning biomass estimates were correlated with partyboat catches in three different areas and the 1973 spawning biomass estimated from the resulting regression line. The estimates derived by these alternate methods are 6,970 tons, 4,730 tons, and 6,210 tons. All estimates are below the 10,000 ton spawning population minimum and thus there is no excess by which a harvest under Section 8388.5 of the Fish and Game Code could be allowed. (17pp.

Status of Pacific Mackerel spawning population, 1974

This is the second annual report on the status of the spawning population of the Pacific mackerel as required by Section 8388.3 of the Fish and Game Code. During 1973 and early 1974, several methods of determining population size were used to estimate the spawning population size of Pacific mackerel stocks north of Point Eugenia, Baja California. The estimated Pacific mackerel spawning population obtained by tagging procedures was 2,025 tons. Two alternate spawning biomass estimates also were obtained using partyboat catches fitted to regression lines. The estimates derived by these alternate methods are 4,675 tons, and 8,380 tons. All 1974 estimates are below the 10,000 ton spawning population minimum set in Section 8388.3 of the Fish and Game Code and thus no harvest under Section 8388.5 of the Fish and Game Code could be allowed. (10pp.

Fish and bivalves at Bolsa Chica Marsh re-establishment project; Progress report III

The objectives of our fish and bivalve study are: 1. Determine changes in the number of species of fish and bivalves before Phase I and during Phase 1 at Bolsa Chica Marsh. 2. Determine if California Department of Fish and Game's predicted benefits in Phase I were achieved by increases in fish species. 3. Determine influences of water management practices upon fish and bivalve composition. Thirteen species of fish and five species of bivalves were collected from Inner Bolsa Bay and South Bolsa Slough. Deepbody anchovy, Anchoa compressa; jacksmelt, Atherinopsis californiensis; longjaw mudsucker, Gillichthys mirabilis; specklefin midshipman, Porichthys myriaster; round stingray, Urolophus halleri; banded chione, Chione californiensis; bentnose clam, Macoma nasuta; and common littleneck clam, Protothaca staminea have not been reported previously from Inner Bolsa Bay. Nine species of fish and four species of bivalves were collected from outer Bolsa Bay. Yellowfin goby, Acanthogobius flavimanus; longjaw mudsucker; tilapia, Tilapia mossambica; and bay pipefish, Syngnathus leptorhynchus have not been reported previously from Outer Bolsa Bay. (11pp.

Results of the 1977 southern California pismo clam survey

A Pismo clam, Tivela stultorum, survey was conducted in January 1977 on selected southern California beaches. Effort and catch information was collected through clammer interviews. Estimates for the two day survey were 1,596 clammers spending 2,506 hours to take 6,139 clams. Comparisons were made between the 1977 survey results and previous surveys. Clams were collected for length and age studies. Compliance to the 4.5-inch (114.3 mm) minimum size limit appeared to be good. (15pp.

Results of the 1976 southern California pismo clam census

A Pismo clam, Tivela stultorum, census was conducted in January 1976 on selected southern California beaches. Effort and catch information was collected through clamer interviews. Estimates for January 17 on beaches sampled were 3,296 clammer-hours, 2,170 clammers, and 10,739 legal clams (4.5 inches or larger) harvested. Clams were collected for age and growth studies. Samples of clams from the Long Beach to Newport Beach pier area demonstrate the fastest growth rates of any Pismo clams reported in the literature. Clams begin to be recruited to the fishery at age 40 months. (14pp.) The 1974 year class was the largest on beaches sampled. Recruitment to the fishery will be poor for the 1976-77 and 1977-78 seasons and clamming will be dependent on large older clams

Fish and bivalves at Bolsa Chica Marsh re-establishment project, Report IV

The objectives of this study are: 1. Determine changes in the number of species of fishes and bivalves before Phase I and during Phase I at Bolsa Chica Marsh. 2. Determine if California Department of Fish and Game's predicted benefits in Phase I were achieved by increases in fish species. 3. Determine influences of water management practices upon fish and bivalve composition. This report is divided into two major topics: (1) the fishes and the bivalves collected in July, August, and September 1980 and (2)a discussion of the project objectives after four quarters of sampling. Fifteen species of fishes and eight species of bivalves were collected from inner Bolsa Bay and south Bolsa slough in July, August, and September 1980. Giant kelpfish, Heterostichus rostratus; gray smoothhound, Mustelus californicus; California halibut, Paralichthys californicus; yellowfin croaker, Umbrina roncador; Washington clam, Saxidomus nuttalli; egg cockle, Laevicardium substriatum; and a small burrowing clam, Cooperella subdiaphana, have not been previously reported from inner Bolsa Bay. The number of fish species in outer Bolsa Bay changed from 10 prior to Phase I to 18 during Phase I. The number of fish species in inner Bolsa Bay and south Bolsa slough changed from three prior to Phase I to 24 during Phase I. Eleven species of bivalves were found in outer Bolsa Bay both prior to Phase I and during Phase I. The number of bivalve species in inner Bolsa Bay changes from two prior to Phase I to nine during Phase I. With the water management practices of Phase I in inner Bolsa Bay and south Bolsa slough; the number of resident fish species is 14, while the number of resident bivalves is five. All three study objectives are discussed and recommendations are made on water management practices concerning fishes and bivalves in inner Bolsa Bay and south Bolsa slough. (33pp.