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Meza Figueroa, Edgar Moisés - One of the best experts on this subject based on the ideXlab platform.
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Impacto de las variaciones ambientales climatológicas en las larvas de anchoveta Engraulis ringens (Jenyns, 1842) y sardina Sardinops sagax (Jenyns, 1842) usando un modelo de balance energético dinámico
Lima, 2016Co-Authors: Meza Figueroa, Edgar MoisésAbstract:Aplicamos la teoría del Balance Energético Dinámico (DEB) a dos especies de pequeños pelágicos: la anchoveta (Engraulis ringens) y la sardina (Sardinops sagax) del Sistema Norte de la Corriente de Humboldt (NHCS) frente a Perú. El modelo DEB fue forzado por factores ambientales obtenidos de la Clorofila-a Superficial del Mar a partir del satélite MODIS y la Temperatura Superficial del Mar del modelo NOAA-NCDC en el periodo 2003-2014. Se extendió el modelo DEB estándar para comparar la respuesta bioenergética de la anchoveta y la sardina a variaciones ambientales estacionales. Se encontró que: (i) el alimento fue directamente restrictivo sobre la longitud asintótica en ambas especies, mientras que la temperatura afectó la velocidad de los procesos y tasas metabólicas; (ii) las larvas de sardina sobrevivieron más tiempo en condiciones de inanición respecto de las larvas de anchoveta; la temporada de desove influyó de manera directa y significativa (p
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Impacto de las variaciones ambientales climatológicas en las larvas de anchoveta Engraulis ringens (Jenyns, 1842) y sardina Sardinops sagax (Jenyns, 1842) usando un modelo de balance energético dinámico
'Universidad Peruana Cayetano Heredia', 2016Co-Authors: Meza Figueroa, Edgar MoisésAbstract:TesisAplicamos la teoría del Balance Energético Dinámico (DEB) a dos especies de pequeños pelágicos: la anchoveta (Engraulis ringens) y la sardina (Sardinops sagax) del Sistema Norte de la Corriente de Humboldt (NHCS) frente a Perú. El modelo DEB fue forzado por factores ambientales obtenidos de la Clorofila-a Superficial del Mar a partir del satélite MODIS y la Temperatura Superficial del Mar del modelo NOAA-NCDC en el periodo 2003-2014. Se extendió el modelo DEB estándar para comparar la respuesta bioenergética de la anchoveta y la sardina a variaciones ambientales estacionales. Se encontró que: (i) el alimento fue directamente restrictivo sobre la longitud asintótica en ambas especies, mientras que la temperatura afectó la velocidad de los procesos y tasas metabólicas; (ii) las larvas de sardina sobrevivieron más tiempo en condiciones de inanición respecto de las larvas de anchoveta; la temporada de desove influyó de manera directa y significativa (p
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Impacto de las variaciones ambientales climatológicas en las larvas de anchoveta Engraulis ringens (Jenyns, 1842) y sardina Sardinops sagax (Jenyns, 1842) usando un modelo de balance energético dinámico
Lima, 2016Co-Authors: Meza Figueroa, Edgar MoisésAbstract:Tesis (Maestro en Ciencias del Mar). Universidad Peruana Cayetano Heredia.Aplicamos la teoría del Balance Energético Dinámico (DEB) a dos especies de pequeños pelágicos: la anchoveta (Engraulis ringens) y la sardina (Sardinops sagax) del Sistema Norte de la Corriente de Humboldt (NHCS) frente a Perú. El modelo DEB fue forzado por factores ambientales obtenidos de la Clorofila-a Superficial del Mar a partir del satélite MODIS y la Temperatura Superficial del Mar del modelo NOAA-NCDC en el periodo 2003-2014. Se extendió el modelo DEB estándar para comparar la respuesta bioenergética de la anchoveta y la sardina a variaciones ambientales estacionales. Se encontró que: (i) el alimento fue directamente restrictivo sobre la longitud asintótica en ambas especies, mientras que la temperatura afectó la velocidad de los procesos y tasas metabólicas; (ii) las larvas de sardina sobrevivieron más tiempo en condiciones de inanición respecto de las larvas de anchoveta; la temporada de desove influyó de manera directa y significativa (p
Cd Van Der Lingen - One of the best experts on this subject based on the ideXlab platform.
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Spatial variability in branchial basket meristics and morphology of southern African sardine Sardinops sagax
African Journal of Marine Science, 2016Co-Authors: Izwandy Idris, Coleen L. Moloney, Cd Van Der LingenAbstract:We examined spatial variability in meristic and morphological characteristics of the branchial basket of sardine Sardinops sagax collected from four geographical regions around the southern African coast, namely Namibia and the South African west, south and east coasts. Our analysis tested the hypothesis of three putative sardine stocks off South Africa, one in each of the three geographical regions. We therefore collected fish data from Namibia to compare with South Africa, because sardine from the two countries are considered to be separate stocks. Morphometric measurements (gill arch length and gill raker spacing) and meristic data (number of gill rakers) were collected from the left side of the first gill arch from a total of 377 sardine, approximately equally divided between the regions. A multivariate general linear model with caudal length as covariate was used to assess differences among fish from the four regions and significant differences were observed, although not always consistently across a...
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diet of the cape fur seal arctocephalus pusillus pusillus at the robberg peninsula plettenberg bay and implications for local fisheries
African Journal of Marine Science, 2012Co-Authors: J Huisamen, Cd Van Der Lingen, S P Kirkman, L H Watson, V G Cockcroft, R Jewell, Pierre A PistoriusAbstract:Cape fur seals Arctocephalus pusillus pusillus were harvested to extirpation on the Robberg Peninsula, Plettenberg Bay, on the south-east coast of South Africa, between the 17th and early 20th centuries. Seals returned to Robberg in small numbers during the early 1990s and their numbers subsequently increased. We studied the diet of this increasing population using faecal (scat) sampling to determine: the species composition and size of prey in the diet of Cape fur seals at Robberg; to explore temporal variation in the diet; and to investigate the potential for competition between seals and the fisheries around Plettenberg Bay. Of the 445 scats collected, 90% contained hard prey remains and 15 teleost prey species were represented in the 3 127 otoliths that could be identified. The seals’ most important prey species in terms of numerical abundance, frequency of occurrence and mass in the diet, were anchovy Engraulis encrasicolus, sardine Sardinops sagax, horse mackerel Trachurus capensis, sand tongue-fish...
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Indicators of sustainable fishing for South African sardine Sardinops sagax and anchovy Engraulis encrasicolus
African Journal of Marine Science, 2006Co-Authors: T. Fairweather, Cd Van Der Lingen, Anthony J. Booth, Laurent Drapeau, J. J. Van Der WesthuizenAbstract:Six indicators were investigated for South African sardine Sardinops sagax and anchovy Engraulis encrasicolus: mean length of catch, length-at-50% maturity, total mortality, exploitation rate, ratio of bycatch, and centre of gravity of commercial catches. Sardine length-at-50% maturity is the most promising as a descriptive indicator because it is positively correlated with population size for an extensive time period (1953–2005). The remaining indicators were limited by shorter data-series (1984–2005). However, mean length of catch, ratio of bycatch and exploitation rate were found to be useful when considered in conjunction with other indicators. The centre of gravity of commercial sardine catches has shown a significant eastward shift from the West Coast, whereas that of anchovy has remained off that coast. Ratio of bycatch indicates that school composition is a reliable descriptive indicator of relative abundance in the two species. Fewer indicators for anchovy were useful, which is attributed to this...
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Density-dependent changes in reproductive parameters and condition of southern Benguela sardine Sardinops sagax
African Journal of Marine Science, 2006Co-Authors: Cd Van Der Lingen, Pierre Fréon, T. Fairweather, J. J. Van Der WesthuizenAbstract:The sardine Sardinops sagax population in the southern Benguela has undergone substantial fluctuations in size over the past 50 years, collapsing from an apparently large population in the 1950s to low levels in the mid-1960s, remaining low for the next two decades, and recovering from the late 1980s to a population size that is now similar to or larger than that which occurred during the 1950s. Marked changes in condition and reproductive parameters of sardine have also occurred during this period; condition and standardised gonad mass are higher and length-at-maturity is lower at low population size compared with high population size. The correspondence between the temporal patterns in condition, reproductive parameters and population size are strongly suggestive of density-dependence, and indicate a compensatory response arising from reduced intra-specific competition. This is likely to have resulted from greater per capita food intake, improved body condition and hence faster growth, thus enabling fis...
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Characterising and comparing the spawning habitats of anchovy Engraulis encrasicolus and sardine Sardinops sagax in the southern Benguela upwelling ecosystem
African Journal of Marine Science, 2005Co-Authors: Nm Twatwa, Coleen L. Moloney, Cd Van Der Lingen, Laurent Drapeau, John G. FieldAbstract:The spawning habitats of anchovy Engraulis encrasicolus and sardine Sardinops sagax in the southern Benguela upwelling ecosystem were characterised by comparing their egg abundances with environmental variables measured concomitantly during two different survey programmes: the South African Sardine and Anchovy Recruitment Programme (SARP), which comprised monthly surveys conducted during the austral summers of 1993/94 and 1994/95; and annual pelagic spawner biomass surveys conducted in early summer (November/December) from 1984 to 1999. Eggs were collected using a CalVET net. Physical variables measured included sea surface temperature (SST), surface salinity, water depth, mixed-layer depth, and current and wind speeds; biological variables measured included phytoplankton biomass, and zooplankton biomass and production. Spawning habitat was identified by construction of quotient curves derived from egg abundance data and individual environmental variables, and relationships between these variables were de...
Larry D Jacobson - One of the best experts on this subject based on the ideXlab platform.
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an ecosystem based hypothesis for climatic effects on surplus production in california sardine Sardinops sagax and environmentally dependent surplus production models
Canadian Journal of Fisheries and Aquatic Sciences, 2009Co-Authors: Larry D Jacobson, Steven J Bograd, Richard H Parrish, Roy Mendelssohn, Franklin B SchwingAbstract:We used environmentally dependent surplus production (EDSP) models to test hypotheses linking changes in habitat area, carrying capacity and surplus production in California sardine (Sardinops saga...
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regimes and stock recruitment relationships in japanese sardine Sardinops melanostictus 1951 1995
Canadian Journal of Fisheries and Aquatic Sciences, 1998Co-Authors: Tokio Wada, Larry D JacobsonAbstract:We used reproductive success, rather than abundance or catch, to identify regimes because reproductive success responds faster to environmental changes. Peak abundance of Japanese sardine during 1951-1995 was about 1000 times higher than minimum abundance. A regime shift occurred in the early 1970s when carrying capacity (measured using spawner-recruit models) increased by about 75 times. We hypothesize that this was due to large-scale changes in the Kuroshio and Oyashio Current systems. Long-term environmental variation (regimes), interannual variability in recruitment success, and density-dependent recruitment and growth rates affected dynamics of Japanese sardine. We hypothesize that density-dependent effects on recruitment of Sardinops spp. are common but usually obscured in short data sets by environmental variability and measurement error. Virtual population analysis and forward-simulation modeling approaches gave similar biomass and recruitment estimates. The relationship between sardine biomass an...
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regimes and stock recruitment relationships in japanese sardine Sardinops melanostictus 1951 1995
Canadian Journal of Fisheries and Aquatic Sciences, 1998Co-Authors: Tokio Wada, Larry D JacobsonAbstract:We used reproductive success, rather than abundance or catch, to identify regimes because reproductive success responds faster to environmental changes. Peak abundance of Japanese sardine during 19...
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stock recruitment models for pacific sardine Sardinops sagax
Canadian Journal of Fisheries and Aquatic Sciences, 1995Co-Authors: Larry D Jacobson, Alec D MaccallAbstract:We used generalized additive models to study the recruitment of Pacific sardine (Sardinops sagax) along western North America and to compare the effects of fishing and environmental factors on the ...
Yoshiro Watanabe - One of the best experts on this subject based on the ideXlab platform.
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year class strength and growth rates after metamorphosis of japanese sardine Sardinops melanostictus in the western north pacific ocean during 1996 2003
Canadian Journal of Fisheries and Aquatic Sciences, 2008Co-Authors: Akihiko Yatsu, Yoshiro Watanabe, Motomitsu Takahashim Takahashi, Hiroshi NishidaAbstract:Growth trajectories during larval to early juvenile stages in Japanese sardine (Sardinops melanostictus) were backcalculated based on the widths of otolith daily increments from 1996 to 2003 in the nursery grounds, Kuroshio–Oyashio transitional waters. Planktonic larvae hatched near Kuroshio have been transported northeastward from the Kuroshio waters to the transitional waters. We show that the somatic growth rates sharply increased after metamorphosis to the early juvenile stage, whereas previously, others showed that growth rate decreases during the larval stage. Otolith growth rates were more variable during the juvenile stage than the larval stage. Interannual variations in the otolith growth rate after metamorphosis explained more than 80% of variation in abundances of recruits (ca. 8–10 months old) in the Pacific coastal waters, whereas no correlation was found between the growth rate during the early larval stage and abundance. Our result was consistent with the hypothesis of growth rate-dependent...
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population decline off the japanese sardine Sardinops melanostictus owing to recruitment failures
Canadian Journal of Fisheries and Aquatic Sciences, 1995Co-Authors: Yoshiro Watanabe, Hiromu Zenitani, Ryo KimuraAbstract:The Japanese sardine Sardinops melanostictus started to decline after 1989. Recruitment to age 1 population was small in four year-classes from 1988 to 1991. The population decline after 1989 resul...
G. Cárdenas - One of the best experts on this subject based on the ideXlab platform.
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Size of the South American sardine (Sardinops sagax) population in the northern part of the Peru upwelling ecosystem after collapse of anchoveta (Engraulis ringens) stocks
Canadian Journal of Fisheries and Aquatic Sciences, 1992Co-Authors: K. R. Patterson, J. Zuzunaga, G. CárdenasAbstract:New estimates of sardine (Sardinops sagax) biomass suggest that a change in state of the Peruvian upwelling ecosystem, previously thought to be from one of anchoveta (Engraulis ringens) dominance to one of equal abundances of sardine and anchoveta, has been a clear switch in dominance from anchoveta to sardine. The sardine stock inhabits the northern part of the Peru upwelling system and extends its distribution into waters off Ecuador. Virtual population analyses show the population to have been considerably larger than was previously thought, with a biomass in 1982 estimated at between 15 and 18 million tonnes. The anchoveta collapse appears to have allowed a large bloom in sardine abundance. Sardine stock size has declined in recent years, concurrently with estimated mortalities in excess of F0.1 and declining recruitment.
