50 research outputs found

    The ENSO signature in sea-surface temperature in the Gulf of California

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    We analyzed 21 years of sea-surface temperature satellite images to explore the spatial signature of the El Niño-Southern Oscillation signal in the Gulf of California. We used empirical orthogonal function analysis to extract the principal mode of the nonseasonal sea-surface temperature variability and compared it to the spatial signature of the Southern Oscillation Index. The first mode accounted for 80% of nonseasonal variability and its amplitude time series was significantly correlated to the Southern Oscillation Index (r = −0.58,P \u3c 0.01). The amplitude of this mode and its statistical relation to the El Niño is stronger during winter, which suggests that forcing of sea-surface temperature variability occurs through the disruption of the wind-driven upwelling corridor along the eastern coast due to El Niño-related atmospheric teleconnections. We also examined weekly time series of coastal sea-surface temperature coastal anomalies along the coast of North America, including the interior of the Gulf of California, during the strong 1997–98 El Niño. We found a poleward propagating signal that reached the mouth of the Gulf of California at the end of spring and continued its poleward propagation along the west coast of the peninsula slightly delayed; it also resulted in warming inside the Gulf of California. This observation may provide an explanation for the variable extension of the El Niño signature along the Pacific coast of North America

    Perspectives for implementing fisheries certification in developing countries

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    This paper discusses the future of the Marine Stewardship Council (MSC), a market-based certification program, in developing countries and exposes the challenges and opportunities for fish producers. The MSC needs to attract the interest of more fishing enterprises from these regions to increase its global presence. Because most fisheries in developing countries cannot meet the MSC standards, or afford the certification process costs, it is suggested that there is a need for developing different levels within the MSC system and additional third-party assessing organizations. MSC certification may mean adoption of improvements in fisheries management and approving fishing regimes in developing countries. However, post-certification benefits may decrease as more fisheries become certified

    Genetic Signature of Rapid IHHNV (Infectious Hypodermal and Hematopoietic Necrosis Virus) Expansion in Wild Penaeus Shrimp Populations

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    Infectious hypodermal and hematopoietic necrosis virus (IHHNV) is a widely distributed single-stranded DNA parvovirus that has been responsible for major losses in wild and farmed penaeid shrimp populations on the northwestern Pacific coast of Mexico since the early 1990's. IHHNV has been considered a slow-evolving, stable virus because shrimp populations in this region have recovered to pre-epizootic levels, and limited nucleotide variation has been found in a small number of IHHNV isolates studied from this region. To gain insight into IHHNV evolutionary and population dynamics, we analyzed IHHNV capsid protein gene sequences from 89 Penaeus shrimp, along with 14 previously published sequences. Using Bayesian coalescent approaches, we calculated a mean rate of nucleotide substitution for IHHNV that was unexpectedly high (1.39×10−4 substitutions/site/year) and comparable to that reported for RNA viruses. We found more genetic diversity than previously reported for IHHNV isolates and highly significant subdivision among the viral populations in Mexican waters. Past changes in effective number of infections that we infer from Bayesian skyline plots closely correspond to IHHNV epizootiological historical records. Given the high evolutionary rate and the observed regional isolation of IHHNV in shrimp populations in the Gulf of California, we suggest regular monitoring of wild and farmed shrimp and restriction of shrimp movement as preventative measures for future viral outbreaks

    Oceans and Coastal Ecosystems and Their Services

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    Ocean and coastal ecosystems support life on Earth and many aspects of human well-being. Covering two-thirds of the planet, the ocean hosts vast biodiversity and modulates the global climate system by regulating cycles of heat, water and elements, including carbon. Marine systems are central to many cultures, and they also provide food, minerals, energy and employment to people. Since previous assessments1 , new laboratory studies, field observations and process studies, a wider range of model simulations, Indigenous knowledge, and local knowledge have provided increasing evidence on the impacts of climate change on ocean and coastal systems, how human communities are experiencing these impacts, and the potential solutions for ecological and human adaptation.Peer reviewe

    Sea surface temperature anomalies, seasonal cycle and trend regimes in the Eastern Pacific coast

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    We used the extended reconstruction of sea surface temperature (ERSST) to analyze the variation of surface temperature and the seasonal cycle along the coast of the eastern Pacific (60° N–60° S, 61 pixels alongshore) from 1950 to 2010 (732 months). First, we analyzed the monthly anomalies and looked for a relationship of such anomalies with total solar irradiance (TSI) and then the Regime Shift Detector (RSD) was applied to detect possible temperature regimes in the series. Afterwards, we calculated a yearly temperature range per pixel (amplitude of seasonal cycle) and through the subtraction of a latitudinal theoretical curve of temperature based on solar irradiance, the residuals of the seasonal cycle were obtained. The results showed an almost complete spatial synchrony and dominance of negative anomalies from 1950 to mid-late 1970's, with a switch to near-zero and positive anomalies that lasted up to late 1990's when a new shift to negative values was detected. Such a shift lasted until the early 2000's when positive anomalies appeared again but there was a change to negative anomalies in the late 2000's. These results were supported by the RSD. The TSI variability shows a clear relationship with that of sea surface temperature anomalies and with the regime changes. This is probably due to a difference in the amount of energy received from the sun. Comparing the "cool regime" versus the "warm regime", the second one received 0.39% more energy (approximately 3 × 10<sup>8</sup> J m<sup>−2</sup>) from the sun. Seasonal cycles show larger ranges at northern latitudes (>40° N), northern tropical-temperate transition zone (20°–26° N) and in the tropical-equatorial band (0°–30° S). The smallest ranges occur at 0°–16° N and 50°–60° S. The residuals (seasonal minus the theoretical curve) indicated a clear modulation due to advection by ocean currents

    Large marine ecosystems of the Indian ocean : assessment, sustainability and management

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    Modeling sardine and anchovy low-frequency variability

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