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Patterson K.R.,Overseas Development Administration | Zuzunaga J.,Instituto del Mar del Peru | Cardenas G.,Instituto del Mar del Peru
Canadian Journal of Fisheries and Aquatic Sciences | Year: 2015

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 F01 and declining recruitment. De nouvelles estimations de la biomasse du pilchard du Chili (Sardinops sagax) portent à croire qu'une modification de l'écosystème de remontées d'eau profonde du Pérou, soit que la dominance de l'anchois du Pérou (Engraulis ringens) aurait fait place à une abondance égale de pilchard et danchois, était réellement la dominance du pilchard sur l'anchois. Le stock de pilchard fréquente le secteur septentrional du systéme de remontées d'eau profonde du Pérou; son aire de répartition se prolonge dans les eaux hauturières de l'Équateur. Des analyses virtuelles de population révèlent que le pilchard était beaucoup plus abondantque I'on croyait; ainsi, sa biomasse en 1982 atteignait entre 15 et 18 millions de tonnes. L'effondrement du stock d'anchois semble avoir favorisé une poussée importante de l'abondance du pilchard. Au cours des dernières années, le stock de pilchard s'est appauvri en même temps que I'on notait un taux de mortalite estimatif supérieur à F0/l et une baisse du taux de recrutement. © 2015, National Research Council of Canada. All rights reserved.

Espinoza P.,Instituto del Mar del Peru | Bertrand A.,CIRAD - Agricultural Research for Development
Journal of Fish Biology | Year: 2014

In this study, historical data available since 1954 were used to get new insight to ontogenetic and spatiotemporal variability in Peruvian anchovy or anchoveta Engraulis ringens diet. Whatever the period, E. ringens foraged mainly on macrozooplankton and the importance of euphausiids in E. ringens diet appears directly related to euphausiids abundance. This bottom-up effect is also observed at smaller scale because the euphausiids fraction increased with E. ringens total length and euphausiids accessibility. Selecting the largest prey, the euphausiids, provides an energetic advantage for E. ringens in its ecosystem where oxygen depletion imposes strong metabolic constraints on pelagic fishes. This study illustrates the plasticity of E. ringens that allows it to cope with its highly variable environment. © 2014 The Fisheries Society of the British Isles.

This paper presents estimates of the von Bertalanffy growth parameters for Jack mackerel T. murphyi caught in Peruvian waters from 1972 to 2012, based on length frequency analysis. L∞ was estimated from the maximum length observed throughout the history of the fishery, and was kept as a fixed parameter in the estimation of k obtained by fitting a growth curve to the monthly progression of modes. The estimated values were: L∞ = 81.6 cm and k = 0.167y-1. It is highlighted that this k values is similar to those estimated by other authors for Peru, and is higher than those estimated for the T. murphyi caught off in Chile. These results suggest that T. murphyi caught in Peru has a faster growth rate than the T. murphyi from Chile. © Los autores.

Dioses T.,Instituto Del Mar Del Peru
Revista Peruana de Biologia | Year: 2013

The age and growth of Jack mackerel Trachurus murphyi Nichols 1920 was determined by the reading and measuring annual growth rings from 977 pairs of otoliths from specimens between 3 and 71 cm total length collected within the Peruvian maritime domain during 1978 and part of 1977 and 1979. The validity of the annual marks was confirmed with 50 otolith with 5 marks or annual zones, and also with the analysis of the monthly marginal increment in 240 otoliths of specimens between 35 and 39 cm obtained from July 1977 to June 1979. From the annual rings measurements and their respective retroestimated sizes, the following parameters of the von Bertalanfy ecuation for growth in length and weight were estimated: infinite length (L∞) = 80.77 cm, infinite weight (W∞) = 3744.10 g, growth coefficient (k) = 0.155, and theoretical age at length 0 (t0) = -0.356. The estimated parameters suggest that the Peruvian T. murphyi has a faster growth rate than the more southern T. murphyi. © Los autores.

Estrella Arellano C.,Instituto del Mar del Peru | Swartzman G.,University of Washington
Fisheries Research | Year: 2010

Since 1996, the Peruvian Marine Research Institute (IMARPE) has been collecting data on catches by vessel, species, weight (kg), gear type and fishing grounds for all major ports of the artisanal fishery. At present, this fishery has exclusive rights to undertake commercial fishing operations within 5 miles from the Peruvian coast. During this period there have been significant changes in the composition and spatial pattern of the artisanal fishery including a reduction in catch of sardine and mullet, and increases in catches of jumbo squid, scallops and dolphin fish. Of particular note was the effect of the El Niño of 1997-1998, with a major reduction in the catch of anchovy and silversides and increases in shellfish (mussels and scallops), reflecting a shift during this period from a pelagic to a benthic dominated system. While the fishery has undergone relatively large changes in species composition of catches there has been a relatively steady level of catch per trip for target species and a modest decrease in numbers of trips in the fishery. To some extent the observed changes reflect changes in environmental conditions, with a warmer period before 1999 and a cooler, higher upwelling period since then. The environmental changes were accompanied by the rapid increase of jumbo squid, a voracious predator on many commercial fish species since 1999. However, some changes reflect changes in economic conditions, for example higher oil prices and decreased selling price of many species resulting an increased focus on high value fisheries and exports including the use of set lines to produce a higher quality end-product and the holding of shellfish in pens in the sea to increase their size and bring a higher price. The Peruvian artisanal fishery features strong seasonal variation in some species, generally sustained catches over a long time period, but changes in species dominance in the catches, reflecting a long-term regime-shift-like pattern in this highly productive region as well as the generalist nature of the fishery. © 2009 Elsevier B.V. All rights reserved.

The Peruvian fisheries exploit renewable natural resources and as such are regulated by a legal framework aiming at ensuring their conservation and sustainable use. The General Fisheries Act, DL N°. 25977, points out that fisheries management systems shall be established for each type of fishery taking into account to the state of exploitation of the fishery resources, reconciling the principles of sustainability and long-term conservation with those aiming at the attainment of the maximum possible economic and social benefits. According to the provisions of the Fisheries Management Regulations approved by SD N°. 011-2007-PRODUCE, the management of the Jack mackerel Trachurus murphyi fisheries includes among others, a fishing access regime that regulates the fleet size and the allocation of fishing licenses, which can only be granted to vessels fishing only for direct human consumption. The obligation to allocate the resources sardine Sardinops sagax, Jack mackerel T. murphyi, and mackerel Scomber japonicus, for direct human consumption has been in force since September 2002, following the ruling established by SD N°. 001-2002-PRODUCE. Other measures currently in force include those establish a minimum mesh size, the ban to catch or land specimens under 31 cm total length limit, the opening and closing of the fishing seasons, and catch limits or annual quotas. These provisions are supplemented by measures for monitoring, control and surveillance, and for the effective conservation and sustainable use of the fishery resources. © Los autores.

This paper analyzes information from IMARPE bio-oceanographic surveys conducted between 1961 and 2011 covering an area from 0 to 100 nm from the coast with observations at depths from 0 to 180 m; information from scientific observers on board Peruvian, Soviet and Cuban factory trawlers operating between 1983 - 1998; as well as time series of sea surface temperature anomalies, depth of the 15 °C isotherm and sea surface salinity from 1950 to date. Three patterns in the vertical distribution and depth of catches of Jack mackerel Trachurus murphyi are identified and described in relation to changing environmental conditions: (1) During strong El Niño (EN) events shoals are at depths between 100 - 200 m, catches are higher and don't change much between day and night; (2) During strong upwellings shoals are shallower, at depths between 0 - 75 m and catches are more oceanic (offshore) and closer to the surface; and, (3) When there is a strengthen Southern Extension of the Cromwell Current (SECC) shoals are at depths between 0 and 300 m, fishing takes place closer to the coast being deeper during the day and shallower during the night. During cold periods there is lower abundance of T. murphyi due to the prevalence of Cold Coastal Waters (CCW) and the offshore shift of the Subtropical Surface Waters (SSW), while abundance is higher during warmer periods associated with EN events and the strengthening of the SECC. A certain latitudinal segregation by sizes in relation to the Pacific Decadal Oscillation is also observed. © Los autores.

This paper analyses information on various macro environmental variables available since 1876 for the Southeast Pacific and more recent data on Jack mackerel Trachurus murphyi (Nichols, 1920) landings and biomass in the Peruvian sea, relating them to probable areas of water masses equivalent to Cold Coastal Waters (CCW) and Subtropical Surface Waters (SSW). It is concluded that the index of the Pacific Decadal Oscillation (PDO) presents expressions of variability that are consistent with those found for the Southern Oscillation Index (SOI) and that the detected changes in biomass of Jack mackerel T. murphyi in the Peruvian sea reflect changes in the availability of the fish stock associated with secular (SOI) and decadal (PDO) variability patterns. These fluctuations in stock availability impact fisheries in Ecuador, Peru and northern Chile, which show significant variations in their landings and would have given a biased picture of the state of abundance, leading to wrong diagnoses of the real situation of the exploited stocks. These patterns of variability would also affect the appearance of El Niño, making them start in the southern hemisphere autumn or spring depending on whether the current PDO is positive or negative. Periods of high (1876 - 1925 and 1976 - 2012) and low (1926 - 1975) variability are also identified in relation to the Euclidean distance of the variances of the SOI; and in relation to the PDO a distinction is made between warm (1925 - 1944 and 1975 - 1994), cold (1945 - 1974) and tempered or interface periods (1895 - 1924 and 1995 - 2012), the latter being explained by the interaction between periods of high variability. © Los autores.

Espino M.,Instituto del Mar del Peru | Yamashiro C.,Instituto del Mar del Peru
Latin American Journal of Aquatic Research | Year: 2012

The southeastern Pacific Ocean is one of the most productive areas of the planet due to its intense oceanic circulation dynamics, whose most important manifestation from the point of view and biological oceanography is the coastal upwelling. This manifestation generates a high primary and secondary production which support important fish stocks that are the basis of the fishing economy of the region. However in this region, variability is a common event that meets regulatory standards of macro-scale such as seasonal, inter-annual, periodical and secular as processes of short, medium, long and very long term. In this scenario appear as environmental factors or manifestations of variability, ENSO (El Niño Southern Oscillation), PDO (Pacific Decadal Oscillation) and PSV (Pacific Secular Variability) as the most conspicuous. Naturally, the temporality and variability factors affect the ecosystem and within it, the resources and its fisheries. These changes are referred to time, space, populations and fisheries. That is, the processes of population dynamics of marine resources, such as recruitment, growth, natural and fishing mortality, are being affected permanently, a different scalar intensities and frequencies. This situation would induce a response in the dynamic populations, which in turn produce states population against each of the moments or environmental scenarios prevailing. This paper presents an analysis of standard patterns and variability factors using environmental variables, biological and fisheries, and identifies scenarios that could explain changes in populations and its fisheries, facilitating the adoption of management measures for each environmental condition. This will allow planning of fisheries to prevent socio-economic and financial collapse, as well as maximize the benefits in different environmental moments.

Tremblay Y.,Institute Pour la Recherche et le Developpement | Tremblay Y.,Instituto del Mar del Peru | Thiebault A.,Institute Pour la Recherche et le Developpement | Mullers R.,University of Cape Town | Pistorius P.,Nelson Mandela Metropolitan University
PLoS ONE | Year: 2014

The study of ecological and behavioral processes has been revolutionized in the last two decades with the rapid development of biologging-science. Recently, using image-capturing devices, some pilot studies demonstrated the potential of understanding marine vertebrate movement patterns in relation to their proximate, as opposed to remote sensed environmental contexts. Here, using miniaturized video cameras and GPS tracking recorders simultaneously, we show for the first time that information on the immediate visual surroundings of a foraging seabird, the Cape gannet, is fundamental in understanding the origins of its movement patterns. We found that movement patterns were related to specific stimuli which were mostly other predators such as gannets, dolphins or fishing boats. Contrary to a widely accepted idea, our data suggest that foraging seabirds are not directly looking for prey. Instead, they search for indicators of the presence of prey, the latter being targeted at the very last moment and at a very small scale. We demonstrate that movement patterns of foraging seabirds can be heavily driven by processes unobservable with conventional methodology. Except perhaps for large scale processes, local-enhancement seems to be the only ruling mechanism; this has profounds implications for ecosystem-based management of marine areas. © 2014 Tremblay et al.

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