Bacterias halófilas extremas deteriorantes en anchoíta salada

En anchoita ( Engraulis anchoita) salada-maduradas, que poseen una actividad de agua (aw) de 0,75 a 0,80 se han encontrado bacterias halófilas . E l objetivo de este trabajo fue determinar la potencial capacidad deteriorante de los grupos bacterianos encontrados. Se realizaron estudios microbiológicos en 100 muestras de anchoíta salada-madurada. E l 71 % de las colonias halladas fueron halófilas extremas y el 29 % estrictas. De acuerdo a sus características bioquímicas se ha reconocido un 31% de Halococcus sp.; 15% de Haloferax spp. 5% de Halobacterium spp. y 7% de Haloarcula spp., el resto se encuentra aún sin identificar. De las bacterias halladas un 30% tienen actividad proteolítica, 30% lipolítica y 15% proteolítica y lipolítica. La presencia de estas bacterias podría llevar a modificaciones irreversibles y no deseables en distintas características sensoriales como olor, color y textura, que limitarían la vida útil de estos productos. La importancia de esta limitación estará dada por el número, las características de las mismas y las condiciones de almacenamiento del producto.

PICES Press, Vol. 11, No. 2, July 2003

Cover [pdf, 1.2 Mb] PICES Science Board and Governing Council hold their first joint meeting [pp. 1-3] [pdf, 0.2 Mb] 3rd International Zooplankton Production Symposium [pp. 4-7] [pdf, 0.6 Mb] The state of the eastern North Pacific entering spring 2003 [pp. 8-9] [pdf, 0.4 Mb] The state of the western North Pacific in 2002 [pp. 10-13] [pdf, 0.6 Mb] The Bering Sea: Current status and recent events [pp. 14-15] [pdf. 0.7 Mb] Patricia Livingston [pp. 16-19] [pdf. 0.5 Mb] Recent changes in the abundance of northern anchovy (Engraulis mordax) off the Pacific Northwest, tracking a regime shift? [pp. 20-21] [pdf. 0.6 Mb] Developing new scientific programs in PICES [pp. 22-26] [pdf. 0.2 Mb] Report of the Yokohama 2003 MODEL Task Team Workshop to develop a marine ecosystem model of the North Pacific Ocean including pelagic fishes [pp. 27-29] [pdf. 0.5 Mb] 3rd PICES Workshop on the Okhotsk Sea and adjacent Areas [pp.30-31] [pdf. 0.4 Mb] Recent oceanographic and marine environmental studies at FERHRI [pp.32-34] [pdf. 0.4 Mb] Symposium Announcement [p. 35] [pdf. 0.3 Mb] PICES announcements [p. 36] [pdf. 0.3 Mb]

Food habits of California Sea Lions (Zalophus californianus) and their impact on Salmonid Fisheries in Monterey Bay, California

In the ocean commercial troll and recreational salmon fishery in Monterey Bay California, California sea lions (Zalophus califomianus) will swim near or follow fishing boats and will depredate fish once hooked. The objectives of the study were to determine the percentage of salmon taken by pinnipeds in commercial and recreational fisheries, identify relative importance of prey items seasonally consumed by sea lions, and determine the proportion of salmonids in the sea lion diet on a seasonal basis. From April 1997 through September 1998, 1041 hours of onboard and dockside surveys of the commercial and recreational salmon fisheries were conducted at the three ports in Monterey Bay, California. Sea lions depreadated 7.9 % of the fish hooked in the commercial fishery in 1997 and 28.6 % in 1998,8.4 % (1997) and 18.3 % (1998) of the CPFV fishery, and 15.6 % (1997) and 17.5 % (1998) of the private skiff fishery. Increased depredation rates in both the commercial and recreational salmon fisheries in 1998 were most likely the result of the large EI Nino Southern Oscillation event that occurred in 1997-1998 during which a greater number of sea lions were present in central California. Prey hardparts identified in sea lion fecal samples collected in Monterey Bay indicated that schooling fishes were the predominant prey fish species, such as market squid (Loligo opalescens), Pacific sardine (Sardinops caeruleus), northern anchovy (Engraulis mordax), and rockfish (Sebastes sp.). Sea lions consumed similar prey species in the summer and fall 1997, winter 1997-98, and spring 1998 (PSI> 70.0) with market squid and northern anchovy being the dominant prey species. However, prey composition changed significantly during the summer 1998 and fall 1998 (PSI < 46.0) because of the increased importance of sardine and rockfish in the diet and the decreased importance of market squid. This report does not intend to imply that salmonids are not a prey species for pinnipeds in the Monterey Bay region, but highlights the difficulties encountered in establishing the role of salmonids in the pinniped diet when analyzing fecal samples. (PDF contains 38 pages).

Feeding Ecology of Humpback Whales in Continental Shelf Waters near Cordell Bank, California

Daytime feeding behavior of humpback whales (Megaptera novaeangliae) in Gulf of the Farallones, California, and adjacent waters was observed during autumn of 1988 to 1990. Bodega Canyon, Cordell Bank, and the Farallon Islands were the primary sites of feeding activity. Fecal samples of whales and zooplankton tows contained euphausiids exclusively, dominated by Thysanoessa spinifera (79%), with lesser amounts of Euphausia pacifica (14%), Nyctiphanes simplex (4%), and Nematoscelis difficilis (3%). In 1988 and 1990, whales also were infrequently observed feeding on small schooling fish, presumably Pacific herring (Clupea pallasii), northern anchovy (Engraulis mordax), and juvenile rockfish (Sebastes spp.). Feeding was the most common behavior observed (52%), and less frequently traveling (23%), milling (21 %), and resting (4%). Whales used different methods to consume euphausiid prey at the surface (0-10 m), in shallow water (11-60 m), and deep water (61-140 m). Humpback whales fed at the surface 56% of time in 1988 and 32% of time in 1990, using primarily lateral lunges to capture swarms of euphausiids. In 1989, no surface feeding was observed; however, deep, long-duration dives were followed by extended surface intervals with many respirations. These 1989 observations coincided with increased prey depth as indicated by depth sounder records of diving whales and prey scattering layers. In 1989, increased prey depth and associated feeding behaviors were strongly associated with unusually high surface temperatures, calm seas, and changes in water circulation. Environmental conditions in 1989 triggered the most intense and wide-spread occurrence of red tide in this region since 1980. Red tide samples collected throughout this period contained Alexandrium (=Gonyaulax) catenella and Noctiluca scintillans. Surface feeding was observed only in 1988 and 1990, when surface prey were available and red tides were very limited in extent, duration, and intensity. Annual variations in humpback whale feeding behavior were related to prey availability which is affected by corresponding environmental conditions. (PDF contains 94 pages)

Survey of fishes and water properties of south San Francisco Bay, California, 1973-82

The objective of this study was to describe the physical and ichthyological changes occurring seasonally and annually in the south San Francisco Bay, based on the results of 2,561 otter trawl and water samples obtained between February 1973 and June 1982. Temperature varied predictably among seasons in a pattern that varied little between years. Salinity also underwent predictable seasonal changes but the pattern varied substantially between years. The most abundant species of fish were northern anchovy (Engraulis mordax), English sole (Parophrys vetulus), and shiner surfperch (Cymatogaster aggregata). The majority of the common fish species were most abundant during wet years and least abundant in dry years. Numeric diversity was highest during the spring and early summer, with no detectable interannual trends. Species composition changed extensively between seasons and between years, particularly years with extremely high or extremely low freshwater inflows. All the common species exhibited clustered spatial distributions. Such spatial clustering could affect the interpretation of data from estuarine sampling programs. Gobies (Family Gobiidae) were more abundant during flood tides than during ebb tides. English sole were significantly more abundant in shallower areas. Shiner surfperch showed significant differences in abundance between sample areas.(PDF file contains 28 pages.)

Analysis of fish diversion efficiency and survivorship in the fish return system at San Onofre Nuclear Generating Station

This study examined the efficiency of fish diversion and survivorship of diverted fishes in the San Onofre Nuclear Generating Station Fish Return System in 1984 and 1985. Generally, fishes were diverted back to the ocean with high frequency, particularly in 1984. Most species were diverted at rates of 80% or more. Over 90% of the most abundant species, Engraulis mordax, were diverted. The system worked particularly well for strong-swimming forms such as Paralobrax clothratus, Atherinopsis californiensis, and Xenistius californiensis, and did not appreciably divert weaker-swimming species such as Porichthys notatus, Heterostichus rostratus, and Syngnathus sp. Return rates of some species were not as high in 1985 as in 1984. Individuals of most tested species survived both transit through the fish return system and 96 hours in a holding net. Some species, such as E. mordox, X. californiensis, and Umbrina roncador, experienced tittle or no mortality. Survivorship of Seriphus politus was highly variable and no Anchoa delicatissima survived. (PDF file contains 22 pages.)

Food habits and dietary variability of pelagic nekton off Oregon and Washington, 1979-1984

The food habits of 20 species of pelagic nekton were investigated from collections made with small-mesh purse seines from 1979-84 off Washington and Oregon. Four species (spiny dogfish, Squalus acanthias; soupfin shark, Galeorhinus zyopterus; blue shark, Prionace glauca; and cutthroat trout, Salmo clarki) were mainly piscivorous. Six species (coho salmon, Oncorhynchus kisutch; chinook salmon, O. tshawytscha; black rockfish, Sebastes melanops; yellowtail rockfish, S. f1avidus; sablefish, Anoplopoma fimbria; and jack mackerel, Trachurus symmetricus) consumed both nektonic and planktonic organisms. The remaining species (market squid, Loligo opalescens; American shad, Alosa sapidissima; Pacific herring, Clupea harengus pallasi; northern anchovy, Engraulis mordax; pink salmon, O. gorbuscha; surf smelt, Hypomesus pretiosus; Pacific hake, Merluccius productus; Pacific saury, Cololabis saira; Pacific mackerel, Scomber japonicus; and medusafish, Icichthys lockingtom) were primarily planktonic feeders. There were substantial interannual, seasonal, and geographic variations in the diets of several species due primarily to changes in prey availability. Juvenile salmonids were not commonly consumed by this assemblage of fishes (PDF file contains 36 pages.)

Growth, mortality, and exploitation of the Engraulidae, with special reference to the anchoveta, Cetengraulis mysticetus, and the colorado, Anchoa naso, in the Eastern Pacific Ocean

ENGLISH: Growth and mortality data for Cetengraulis mysticetus, Anchoa naso, Engraulis mordax, E. ring ens, E. anchoita, E. encraslcbolus, E. japonicus, and E. australis were assembled and compared. Estimates of the coefficients of natural mortality, M, of E. anchoita and Ancboa naso were made from the maximum age of the former and from data for the other species. The relative yields per recruit at different fishing mortality rates and lengths at entry into the fishery were calculated for each species, using what are considered to be the best estimates and other likely values of K, a constant of growth, and M. The maximum yields per recruit are theoretically obtainable at very high fishing mortality rates, except when the length at entry is low relative to the asymptotic length. K and M may be positively related to the temperature and to each other, and if such is the case at higher temperatures greater fishing effort would be needed to attain the maximum yield per recruit. The applicability of the yield-per-recruit approach to the data is discussed, and suggestions for further research are made. SPANISH: Se reunieron y compararon los datos sobre el crecimiento y mortalidad correspondientes a Cetengraulis mysticetus, Anchoa naso, Engraulis mordax, E. ringens, E. anchoíta, E. encrasicbolus, E. japonicus y E. australls. Los estimativos de los coeficientes de la mortalidad natural, M, de E. anchoita y Anchoa naso se obtuvieron según la edad máxima de E. anchoita y según los datos de las otras especies. Se calculó para cada especie el rendimiento relativo por recluta a diferentes tasas de mortalidad por la pesca y a diferentes longitudes de entrada a la pesquería, empleándose lo que se considera que son los mejores estimativos y otros valores probables de K, una constante de crecímíento, y M. El rendimiento máximo por recluta se obtiene teóricamente a tasas muy altas de la mortalidad por la pesca con excepción de cuando la longitud a la entrada es baja en relación a la longitud asintótica. K y M pueden estar relacionadas positivamente a la temperatura y mutuamente, y si este es el caso a temperaturas más altas se necesitará un esfuerzo superior de pesca para obtener el rendimiento máximo por recluta. La aplicabilidad del enfoque a los datos rendimiento-por-recluta es discutido y se hacen sugerencias para otras investigaciones. (PDF contains 66 pages.)

Einfluss von Größen und Fangzeit auf das Fettsäuremuster von Sardellen

Fatty acid composition of fish changes according to season, the catching area, the size, the sexuality, the physiological condition and the quantity of fat. The fatty acid composition was evaluated according to size and the catching season of anchovies Engraulis encrasicolus (L. 1758). It was observed that polyunsaturated fatty acids increasmed to highest level and saturated fatty acids decreased to lowest level in March. On the other hand, in April, it was observed that the saturated fatty acids increased to its highest level, monounsaturated fatty acids decreased to its lowest level.

Distributions and abundances of Pacific sardine (Sardinops sagax) and other pelagic fishes in the California Current Ecosystem during spring 2006, 2008, and 2010, estimated from acoustic–trawl surveys

The abundances and distributions of coastal pelagic fish species in the California Current Ecosystem from San Diego to southern Vancouver Island, were estimated from combined acoustic and trawl surveys conducted in the spring of 2006, 2008, and 2010. Pacific sardine (Sardinops sagax), jack mackerel (Trachurus symmetricus), and Pacific mackerel (Scomber japonicus) were the dominant coastal pelagic fish species, in that order. Northern anchovy (Engraulis mordax) and Pacific herring (Clupea pallasii) were sampled only sporadically and therefore estimates for these species were unreliable. The estimates of sardine biomass compared well with those of the annual assessments and confirmed a declining trajectory of the “northern stock” since 2006. During the sampling period, the biomass of jack mackerel was stable or increasing, and that of Pacific mackerel was low and variable. The uncertainties in these estimates are mostly the result of spatial patchiness which increased from sardine to mackerels to anchovy and herring. Future surveys of coastal pelagic fish species in the California Current Ecosystem should benefit from adaptive sampling based on modeled habitat; increased echosounder and trawl sampling, particularly for the most patchy and nearshore species; and directed-trawl sampling for improved species identification and estimations of their acoustic target stren

Food habits of Steller sea lions (Eumetopias jubatus) off Oregon and northern California, 1986–2007

We described the diet of the eastern stock of Steller sea lions (Eumetopias jubatus) from 1416 scat samples collected from five sites in Oregon and northern California from 1986 through 2007. A total of 47 prey types from 30 families were identified. The most common prey was Pacific hake (Merluccius productus), followed by salmonids (Oncorhynchus spp.), skates (Rajidae), Pacific lamprey (Lampetra tridentata), herrings (Clupeidae), rockfish (Sebastes spp.), and northern anchovy (Engraulis mordax). Steller sea lion diet composition varied seasonally, annually, and spatially. Hake and salmonids were the most commonly identified prey in scats collected during the summer (breeding season), whereas hake and skate were most common in the nonbreeding season. Continued research on Steller sea lion diet and foraging behavior in the southern extent of their range is necessary to address issues such as climate change, interaction with competing California sea lions, and predation impacts on valuable or sensitive fish stocks.

Ichthyoplankton community in the Columbia River plume off Oregon: effects of fluctuating oceanographic conditions

Ichthyoplankton samples were collected at approximately 2-week intervals, primarily during spring and summer 1999−2004, from two stations located 20 and 30 km from shore near the Columbia River, Oregon. Northern anchovy (Engraulis mordax) was the most abundant species collected, and was the primary species associated with summer upwelling conditions, but it showed significant interannual and seasonal fluctuations in abundance and occurrence. Other abundant taxa included sanddabs (Citharichthys spp.), English sole (Parophrys vetulus), and blacksmelts (Bathylagidae). Two-way cluster analysis revealed strong species associations based primarily on season (before or after the spring transition date). Ichthyoplankton abundances were compared to biological and environmental data, and egg and larvae abundances were found to be most correlated with sea surface temperature. The Pacific Decadal Oscillation changed sign (from negative to positive) in late 2002 and indicated overall warmer conditions in the North Pacific Ocean. Climate change is expected to alter ocean upwelling, temperatures, and Columbia River flows, and consequently fish eggs and larvae distributions and survival. Long-term research is needed to identify how ichthyoplankton and fish recruitment are affected by regional and largescale oceanographic proces

Estimating the food consumption of fishes: one step in linking a species with its ecosystem

Details are given of a new software package MAXIMS which may be used to estimate the daily food consumption of fish. The software estimates the feeding times, the rates of ingestion and evacuation and related parameters. Two applications of the program are described. The first pertains to anchovy (Engraulis ringens ) with one feeding period per day, and the second one to juvenile cod (Gadus morhua ), which feed during dawn and dusk.

Exploring the use of neural networks for biomass forecasts in the Peruvian upwelling ecosystem

A pilot study was conducted to study the ability of an artificial neural network to predict the biomass of Peruvian anchoveta Engraulis ringens, given time series of earlier biomasses, and of environmental parameters (ocenographic data and predator abundances). Acceptable predictions of three months or more appear feasible after thorough scrutiny of the input data set.

Trends and Potential Interactions Between Pinnipeds and Fisheries of New England and the U.S. West Coast

Long-term trends in the abundance and distribution of several pinniped species and commercially important fisheries of New England and the contiguous U.S. west coast are reviewed, and their actual and potential interactions discussed. Emphasis is on biological interactions or competition. The pinnipeds include the western North Atlantic stock of harbor seals, Phoca vitulina concolor; western North Atlantic gray seals, Halochoerus grypus; the U.S. stock of California sea lions, Zalophus californianus californianus; the eastern stock of Steller sea lions, Eumetopias jubatus; and Pacific harbor seals, Phoca vitulina richardii. Fisheries included are those for Atlantic cod, Gadus morhua; silver hake, Merluccius bilinearis; Atlantic herring, Clupea harengus; the coastal stock of Pacific whiting, Merluccius productus; market squid, Loligo opalescens; northern anchovy, Engraulis mordax; Pacific her-ring, Clupea pallasi; and Pacific sardine, Sardinops sagax. Most of these pinniped populations have grown exponentially since passage of the U.S. Marine Mammal Protection Act in 1972. They exploit a broad prey assemblage that includes several commercially valuable species. Direct competition with fisheries is therefore possible, as is competition for the prey of commercially valuable fish. The expanding pinniped populations, fluctuations in commercial fish biomass, and level of exploitation by the fisheries may affect this potential for competition. Concerns over pinnipeds impacting fisheries (especially those with localized spawning stocks or at low biomass levels) are more prevalent than concerns over fisheries’ impacts on pinnipeds. This review provides a framework to further evaluate potential biological interactions between these pinniped populations and the commercial fisheries with which they occur.