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Preliminary forecasts of catch and stock abundance for 1993 Alaska Herring Fisheries. Regional Information Report 5J93-06. Alaska Department of Fish and Game, Juneau, Alaska.
Abstract and Figures
The Pacific herring Clupea pallasi sac roe harvest in Alaska for 1993 is projected to be 76,063 tons (ton=2,000 pounds). Herring food/bait harvests for 1993 are projected to be 9,938 tons. Herring spawn-on-pound-kelp fisheries are expected to produce 335 tons of product and spawn- on-wild-kelp harvests are expected to produce an additional 443 tons. The projected sac roe, food/bait, and spawn-on-kelp harvests are expected to increase from the 1992 levels. The 1992 herring harvest had an estimated value to fishermen of 25,160,330, spawn-on-pound-kelp fisheries 2,135,156, and spawn-on-wild-kelp fisheries $487,38 1. Excellent recruitment from the 1988 year class in most areas has caused stock levels to increase. In many areas the 1988 year class appears to be the largest on record. This strong year class will be age 5 for the 1993 harvest.
KEY WORDS: Herring, Clupea pallasi, herring harvest projection, herring stock assessment, herring sac roe fishery, herring food/bait fishery, herring spawn-on-kelp fishery
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... Typically, the kelp constitutes 21-25% of the weight. Sources: Lebida et al. 1984, ADF&G 1986, 2004, Lebida 1986, Hamner 1988, Savikko 1989, Savikko and Page 1990, Funk 1991, Funk and Harris 1992, ADF&G 2018. those that are most easily accessible from the road system. ...
Alaska has the longest coastline of all of the states in the USA. This coastal zone stretches from the temperate zone to past the Arctic circle. Oceanographic conditions vary from quiet estuaries to exposed open coasts. Water temperatures range from over 20°C in the summer in the south to ice covered water in the north. Consequently, the marine flora is plentiful and diverse with over 500 species of seaweeds. Three species of floating kelps occur from the southern boundary to Kodiak Island and westward along the Aleutian Chain. Species of Fucus are dominant in the intertidal along most of the coastline. There is also an abundance of red algae in the intertidal and subtidal. There is only minimal subsistence and commercial utilization of the seaweed resource. The major commercial use of seaweeds is in the herring spawn-on-kelp fishery. “Black seaweed” ( Pyropia sp.) is a special resource for Alaskan Native subsistence harvest. Recently, there has been increasing interest and activity in the commercial mariculture of kelps such as Saccharina latissima and Alaria marginata .
... Typically the kelp constitutes 21-25% of the weight. References: Lebida, Whitmore and Sandone, 1984, ADF&G 1986, 2004., Lebida 1986, Hamner 1988, Savikko 1989, Savikko and Page 1990, Funk 1991, Funk and Harris 1992 There exists a much smaller harvest in SE Alaska of the red alga Porphyra. The main species harvested are Porphyra abbottae and P. torta. ...
... j Approximate estimate of 300,000 t for B.C. based on Hourston (1980) and a maximum of 71,000 t for southeastern Alaska that had a maximal catch of 71,000 t in 1929 (Reid 1971). k Estimate of 1991 catch plus spawning escapment (Funk and Harris 1992). l Estimate based on approximately 1 ⁄ 2 of the Gulf area from Gulland (1970). ...
Indices of abundance for capelin in the Newfoundland area collected since the early 1980s include biomass estimates from offshore acoustic surveys, school surface area near spawning beaches from aerial surveys, and catch rates from the inshore commercial fishery. During the 1990s, the offshore acoustic estimates declined dramatically but the inshore in-dices remained stable. This divergence was coincident with below nor-mal water temperatures and changes in capelin biology. The biological changes included large-scale changes in distribution and later spawning, both of which have been linked to the colder water temperatures, and smaller fish size. The dichotomy in the trends of abundance indices has never been fully reconciled. However, based on data from several sources, it appears that the acoustic surveys were underestimating the true population abundance of capelin offshore. It seems likely that the severe environmental conditions during the early 1990s were the major cause of the changes in biology and behavior of capelin, and these changes had their greatest impact on the acoustic estimates.
Twenty-first century conservation is centered on negotiating trade-offs between the diverse needs of people and the needs of the other species constituting coupled human-natural ecosystems. Marine forage fishes, such as sardines, anchovies, and herring, are a nexus for such trade-offs because they are both central nodes in marine food webs and targeted by fisheries. An important example is Pacific herring, Clupea pallisii in the Northeast Pacific. Herring populations are subject to two distinct fisheries: one that harvests adults and one that harvests spawned eggs. We develop stochastic, age-structured models to assess the interaction between fisheries, herring populations, and the persistence of predators reliant on herring populations. We show that egg- and adult-fishing have asymmetric effects on herring population dynamics - herring stocks can withstand higher levels of egg harvest before becoming depleted. Second, ecosystem thresholds proposed to ensure the persistence of herring predators do not necessarily pose more stringent constraints on fisheries than conventional, fishery driven harvest guidelines. Our approach provides a general template to evaluate ecosystem trade-offs between stage-specific harvest practices in relation to environmental variability, the risk of fishery closures, and the risk of exceeding ecosystem thresholds intended to ensure conservation goals are met.
This paper updates previous reviews of the 1993 stock decline of Pacific herring (Clupea pallasi) in Prince William Sound, Alaska, and focuses on hypotheses about subsequent poor recovery. Recent age structured assessment
modeling with covariate analysis indicates that the population dynamics of the sound’s herring are influenced by oceanic factors,
nutrition, and, most substantially, hatchery releases of juvenile pink salmon. For the 1993 decline, poor nutrition remains
the most probable cause with disease a secondary response. Concerning poor recovery, we examined 16 potential factors and
found three to be causal: oceanic factors, poor nutrition, and hatchery releases of juvenile pink salmon. Absences of strong
year classes at both Sitka and Prince William Sound after 1993 indicate the action of large-scale ocean processes. Beyond
regional-scale environmental factors, two factors specific to the sound influence the population dynamics of herring and are
likely impeding recovery. First, pink salmon fry releases have increased to about 600 million annually and may disrupt feeding
in young herring, which require adequate nutrition for growth and overwintering survival. Juvenile pink salmon and age-1 herring
co-occur in nearshore areas of bays in late spring and summer, and available data on dietary overlap indicates potential competition
between the age-1 juvenile herring and juvenile pink salmon. Field studies demonstrate that juvenile herring reduce food intake
substantially in the presence of juvenile pink salmon. Second, overwintering humpback whales may consume potentially large
amounts of adult herring, but further studies must confirm to what extent whale predation reduces herring biomass.
The 1991-93 El Niiio-Southern Oscdation (ENSO) event first appeared in the northern Gulf of Alaska in autumn 1991 with warm sea-surface temperatures. In winter 1992, there were pulses of increased sea level and anomalous circulation. El Niiio conditions persisted at least through summer 1993. The effects of this ENSO event on major groundfish species and Pacific herring in the northern Gulf of Alaska were examined and com- pared with the effects of previous ENSO events. There is little evidence that the 1991-93 or 1982-83 ENSO events affected landings of walleye pollock, Pacific cod, Pacific halibut, or arrowtooth flounder. Some changes in distribution of groundfish species were observed in 1993, but the effect was similar to changes observed in non-ENS0 warm years. In general, warm ocean condi- tions have a positive effect on recruitment of northern stocks, but ENSO events appear to have an inconsis- tent effect on year-class strength within species and among different species. For example, strong year classes of hal- ibut and arrowtooth flounder sometimes, but not always, coincide with ENSO events; ENSO events are associ- ated with moderate to weak year classes of cod and pollock. However, post-ENS0 warm years often are as- sociated with strong recruitment of many groundfish species. Major changes have occurred in the Gulf of Alaska ecosystem since 1977. The influence of the 1976 ENSO event in precipitating these changes and the role of the hequency or strength of subsequent El Nifio events is presently unknown. Herring and other stocks of small pelagic fishes may be more affected by ENSO events. In particular, decreased catches, recruitment, and weight- at-age of herring are sometimes associated with ENSO events. Furthermore, a variety of seabirds which feed mostly on pelagic forage fishes or the pelagic juvenile stages of groundfish suffered widespread mortalities and breeding failures in the Gulf of Alaska during the ENSO
The 1991-93 El Nino-Southern Oscillation (ENSO) event first appeared in the northern Gulf of Alaska in autumn 1991 with warm sea-surface temperatures. In winter 1992, there were pulses of increased sea level and anomalous circulation. El Nino conditions persisted at least through summer 1993. The effects of this ENSO event on major groundfish species and Pacific herring in the northern Gulf of Alaska were examined and compared with the effects of previous ENSO events. There is little evidence that the 1991-93 or 1982-83 ENSO events affected landings of walleye pollock, Pacific cod, Pacific halibut, or arrowtooth flounder. Some changes in distribution of groundfish species were observed in 1993, but the effect was similar to changes observed in non-ENSO warm years. In general, warm ocean conditions have a positive effect on recruitment of northern stocks, but ENSO events appear to have an inconsistent effect on year-class strength within species and among different species. For example, strong year classes of halibut and arrowtooth flounder sometimes, but not always, coincide with ENSO events; ENSO events are associated with moderate to weak year classes of cod and pollock. However, post-ENSO warm years often are associated with strong recruitment of many groundfish species. Major changes have occurred in the Gulf of Alaska ecosystem since 1977. The influence of the 1976 ENSO event in precipitating these changes and the role of the frequency or strength of subsequent El Nino events is presently unknown. Herring and other stocks of small pelagic fishes may be more affected by ENSO events. In particular, decreased catches, recruitment, and weight-at-age of herring are sometimes associated with ENSO events. Furthermore, a variety of seabirds which feed mostly on pelagic forage fishes or the pelagic juvenile stages of groundfish suffered widespread mortalities and breeding failures in the Gulf of Alaska during the ENSO years of 1983 and 1993. These effects on seabirds were also observed over a wider geographic range, from California to the western Bering Sea.
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