Caso de estudio sobre el uso de bases de datos ambientales de baja resolución espacial, como una alternativa para inferir hábitat de desove.

En este trabajo se prueba la factibilidad de utilizar datos ambientales de baja resolución y fácil obtención para inferir hábitat de desove de la sardina monterrey del Golfo de California, en el dominio de la temperatura. Se compararon resultados publicados, basados en mediciones de temperatura asociadas al muestreo biológico, con cálculos a partir de datos extraídos de una base pública. Los resultados muestran que existen similitudes importantes entre ambas estimaciones, a pesar de las grandes diferencias entre las dos fuentes de datos. Este resultado es relevante para algunas iniciativas en curso, donde se pretende incorporar información ambiental, de fácil acceso y oportuna, a sistemas de información para la pesquería de sardina del Golfo de California

Interannual correlations between sea surface temperature and concentration of chlorophyll pigment off Punta Eugenia, Baja California, during different remote forcing conditions

Interannual correlation between satellite-derived sea surface temperature (SST) and surface chlorophyll a (Chl a) are examined in the coastal upwelling zone off Punta Eugenia on the west coast of the Baja California Peninsula, an area than has been identified as having intense biological productivity and oceanographic transition between midlatitude and tropical ocean conditions. We used empirical orthogonal functions (EOF) analysis separately and jointly on the two fields from 1997 through 2007, a time period dominated by different remote forcing: ENSO (El Niño-Southern Oscillation) conditions (weak, moderate and strong) and the largest intrusion of subarctic water reported in the last 50 years. Coastal upwelling index anomalies (CUI) and the multivariate ENSO index (MEI) were used to identify the influence of local (wind stress) and remote (ENSO) forcing over the interannual variability of both variables. The spatial pattern of the individual EOF1 analysis showed the greater variability of SST and Chl a offshore, their corresponding amplitude time series presented the highest peaks during the strong 1997-2000 El Niño-La Niña cycles and during the 2002-2004 period associated to the intrusion of subarctic water. The MEI is well correlated with the individual SST principal component (R ≈ 0.67, P 0.4) mainly regulated by ENSO cycles. This was spatially revealed when we calculated the homogeneous correlations for the 1997-1999 El Niño-La Niña period and during the 2002-2004 period, the intrusion of subarctic water period. Both, SST and Chl a showed higher coupling and two distinct physical-biological responses: on average ENSO influence was observed clearly along the coast mostly in SST, while the subarctic water influence, observed offshore and in Bahía Vizcaíno, mostly in Chl a. We found coastal chlorophyll blooms off Punta Eugenia during the 2002-2003 period, an enrichment pattern similar to that observed off the coast of Oregon. These chlorophyll blooms are likely linked to high wind stress anomalies during 2002, mainly at high latitudes. This observation may provide an explanation of why Punta Eugenia is one of the most important biological action centers on the Pacific coast. © Author(s) 2014

Recent trends in sea surface temperature off Mexico

Changes in global mean sea surface temperature may have potential negative implications for natural and socioeconomic systems; however, measurements to predict trends in different regions have been limited and sometimes contradictory. In this study, an assessment of sea surface temperature change signals in the seas off Mexico is presented and compared to other regions and the world ocean, and to selected basin scale climatic indices of the North Pacific, the Atlantic and the tropical Pacific variability. We identified eight regions with different exposure to climate variability: In the Pacific, the west coast of the Baja California peninsula with mostly no trend, the Gulf of California with a modest cooling trend during the last 20 to 25 years, the oceanic area with the most intense recent cooling trend, the southern part showing an intense warming trend, and a band of no trend setting the boundary between North-Pacific and tropical-Pacific variability patterns; in the Atlantic, the northeast Gulf of Mexico shows cooling, while the western Gulf of Mexico and the Caribbean have been warming for more than three decades. Potential interactions with fisheries and coastal sensitive ecosystems are discusse

Dinámica espacio-temporal de organismos precursores de marea roja en la costa Pacífica de América del Norte y Centroamérica

La región costera del Pacífico de Centro y Norte America ha sido afectada de manera frecuente por fenómenos que se denominan proliferaciones algales nocivas o en inglés, "Harmful Algal Blooms" (HAB). A pesar de la gran cantidad de efectos en la salud pública, las actividades económicas y el medio ambiente, aún existe una abrumadora carencia de información en el tema. Esto no permite establecer si las causas principales de este evidente aumento en el número e intensidad de los eventos son naturales o antropogénicas. La incrementada utilización de las zonas costeras para actividades humanas encuentra paralelo en el denominado cambio climático, lo que dificulta discriminar entre la posible influencia de estos dos fenómenos. Series de datos de larga duración en regiones reducidas, así como las observaciones esporádicas realizadas cuando se presenta algún evento, nos permite comparar regímenes climáticos, condiciones geográficas, disponibilidad de nutrientes (incluyendo la eutroficación) y parámetros oceanográficos que promueven o permiten el desarrollo y mantenimiento de las proliferaciones, haciendo evidentes cambios drásticos en la biodiversidad y la biogeografía de los organismos productores de HA

Dinámica espacio-temporal de organismos precursores de marea roja en la costa Pacáfica de América del Norte y Centroamérica

La región costera del Pacífico de Centro y Norte America ha sido afectada de manera frecuente por fenómenos que se denominan proliferaciones algales nocivas o en inglés, "Harmful Algal Blooms" (HAB). A pesar de la gran cantidad de efectos en la salud pública, las actividades económicas y el medio ambiente, aún existe una abrumadora carencia de información en el tema. Esto no permite establecer si las causas principales de este evidente aumento en el número e intensidad de los eventos son naturales o antropogúnicas. La incrementada utilización de las zonas costeras para actividades humanas encuentra paralelo en el denominado cambio climático, lo que dificulta discriminar entre la posible influencia de estos dos fenómenos. Series de datos de larga duración en regiones reducidas, así como las observaciones esporádicas realizadas cuando se presenta algZapotitlánn evento, nos permite comparar regímenes climáticos, condiciones geográficas, disponibilidad de nutrientes (incluyendo la eutroficaciZapotitlánn) y parámetros oceanogrZapotitlánficos que promueven o permiten el desarrollo y mantenimiento de las proliferaciones, haciendo evidentes cambios drZapotitlánsticos en la biodiversidad y la biogeografía de los organismos productores de HA

Spatial-temporal dynamics of red tide precursor organisms at the Pacific coast of North and Central America [Dinámica espacio-temporal de organismos precursores de marea roja en la costa Pacáfica de América del Norte y Centroamérica]

The Pacific coast of Central and North America has long been and still is impacted by the flourishing of microalgal populations known as Harmful Algal Blooms (HABs). The organisms that have caused recent HABs episodes in the region are among others, Gymnodinium catenatum, Pyrodinium bahamense var. compressum, and recently Cochlodinium cf. catenatum. In spite of the accumulated effects on the human health, the economic activities and the environment, scarce information is available on the subject. The augmented use of coastal zones for human activities is also paralleled by increased awareness of global climate changes. Thus, it is not an easy task to discriminate anthropogenic or natural phenomena, or both, as the major driving forces. The long-term data sets available for limited regions, as well as some sporadic observations during notorious blooms, allowed us to discriminate major changes in the biodiversity and biogeography of HAB organisms. Main changes refer to number of events, covered area, duration and frequency, number of blooming species and appearance of not previously reported harmful taxa. The variables more clearly related to these dynamic phenomena, seems to be sea surface temperature and wind force, but it is not yet possible to weight their contributions. The participation of rain is not fully evaluated to date. The collaborative communication among small-budget monitoring operations in the region allowed to "pass the voice" about peaking concentrations of HAB organisms, diminishing the risk of poisoning

Spatial-temporal dynamics of red tide precursor organisms at the Pacific coast of North and Central America [Dinámica espacio-temporal de organismos precursores de marea roja en la costa Pacífica de América del Norte y Centroamérica]

The Pacific coast of Central and North America has long been and still is impacted by the flourishing of microalgal populations known as Harmful Algal Blooms (HABs). The organisms that have caused recent HABs episodes in the region are among others, Gymnodinium catenatum, Pyrodinium bahamense var. compressum, and recently Cochlodinium cf. catenatum. In spite of the accumulated effects on the human health, the economic activities and the environment, scarce information is available on the subject. The augmented use of coastal zones for human activities is also paralleled by increased awareness of global climate changes. Thus, it is not an easy task to discriminate anthropogenic or natural phenomena, or both, as the major driving forces. The long-term data sets available for limited regions, as well as some sporadic observations during notorious blooms, allowed us to discriminate major changes in the biodiversity and biogeography of HAB organisms. Main changes refer to number of events, covered area, duration and frequency, number of blooming species and appearance of not previously reported harmful taxa. The variables more clearly related to these dynamic phenomena, seems to be sea surface temperature and wind force, but it is not yet possible to weight their contributions. The participation of rain is not fully evaluated to date. The collaborative communication among small-budget monitoring operations in the region allowed to "pass the voice" about peaking concentrations of HAB organisms, diminishing the risk of poisoning

Comparison of ecological diversity and species composition of macroalgae, Benthic macroinvertebrates, And fish assemblages between two tropical rocky reefs [Comparaci�n de la diversidad ecol�gica y composici�n de especies de ensambles de macroalgas, Macroinvertebrados bent�nicos y peces en dos arrecifes rocosos tropicales]

Within the marine environment, the rocky shores are recognized for their high species diversity and particularly transitional zones represent areas of biotic mix, promoted by historical and ecological natural variations that allow the presence of taxa from different regions and which present dissimilar biological traits. An extensive survey describes the benthic macroalgae, macroinvertebrates (molluscs, crustaceans, and echinoderms), and fish assemblages at two rocky reefs, Islas Marietas and near Tehuamixtle, in a tropical-temperate transitional zone in the Pacific waters of central Mexico using traditional ecological indices (richness, diversity, and evenness) and complementary taxonomic distinctness indices. Biological material inside each of ten randomly-chosen quadrants (25 � 25 cm) placed along two 50 m transects oriented parallel to the coastline, between 6 and 2 m depth was collected. From field collections, 204 species were identified: macroalgae (22), molluscs (55), crustaceans (78), echinoderms (11), and fish (38). The structure of macroalgae, macroinvertebrates and fishes was similar between sites. Species of macroalgae, molluscs, and fishes were more diverse in summer; crustaceans and echinoderms were more diverse in winter. Our results and the literature suggest a latitudinal pattern of lower seasonal changes in echinoderms and crustaceans at high latitudes, as compared to southern regions of the Mexican tropical Pacific. � 2014 Universidad de Valparaiso. All rights reserved

Comparison of ecological diversity and species composition of macroalgae, Benthic macroinvertebrates, And fish assemblages between two tropical rocky reefs [Comparación de la diversidad ecológica y composición de especies de ensambles de macroalgas, Macroinvertebrados bentónicos y peces en dos arrecifes rocosos tropicales]

Within the marine environment, the rocky shores are recognized for their high species diversity and particularly transitional zones represent areas of biotic mix, promoted by historical and ecological natural variations that allow the presence of taxa from different regions and which present dissimilar biological traits. An extensive survey describes the benthic macroalgae, macroinvertebrates (molluscs, crustaceans, and echinoderms), and fish assemblages at two rocky reefs, Islas Marietas and near Tehuamixtle, in a tropical-temperate transitional zone in the Pacific waters of central Mexico using traditional ecological indices (richness, diversity, and evenness) and complementary taxonomic distinctness indices. Biological material inside each of ten randomly-chosen quadrants (25 × 25 cm) placed along two 50 m transects oriented parallel to the coastline, between 6 and 2 m depth was collected. From field collections, 204 species were identified: macroalgae (22), molluscs (55), crustaceans (78), echinoderms (11), and fish (38). The structure of macroalgae, macroinvertebrates and fishes was similar between sites. Species of macroalgae, molluscs, and fishes were more diverse in summer; crustaceans and echinoderms were more diverse in winter. Our results and the literature suggest a latitudinal pattern of lower seasonal changes in echinoderms and crustaceans at high latitudes, as compared to southern regions of the Mexican tropical Pacific. © 2014 Universidad de Valparaiso. All rights reserved

Worldwide large-scale fluctuations of sardine and anchovy populations

Decade-scale regimes of sardine #Sardinops sagax and anchovy #Engraulis spp. have been observed in the productive coastal waters of the North-Western, North-Eastern and South-Eastern Pacific and the South-Eastern Atlantic. In each of these systems, the two genera fluctuate out of phase with each other. The subdominant genus may initiate a recovery while the other species is still abundant, so population growth is not necessarily a response to a vacant niche. Rather, it appears to be triggered by formation of one or a few powerful year-classes. At high population levels, quality of sardine and their eggs decreased in Japan, leading to decreased production and survival of eggs, poor year-classes and stock collapse. Excessive fishing of strong year-classes early in the recovery stage may prevent a species from assuming dominance, so influencing the natural succession of species. This may greatly alter the structure and functioning of an ecosystem. For example, a mesopelagic forage fish may replace an epipelagic one, with severe repercussions for predators that can only feed in the upper ocean, e.g. some seabirds. Biological factors also may influence the succession of forage fish. For example, off California, peaks in abundance of predatory species such as bonita #Sarda, and chub mackerel #Scomber separate those of the planktivorous sardine and anchovy. In the Pacific Ocean, sardine distribution has changed greatly. Compared with its range when scarce, a population at a high level of biomass can extend 1 000-1 800 miles farther along the coast and 400-2 200 miles farther out to sea. In different periods of high biomass, sardine did not always have the same distribution. In the 1930s and 1940s, near simultaneous fluctuations of sardine in the North-Western and North-Eastern Pacific were in phase. In the 1980s and 1990s, sardine in the North-Western and South-Eastern Pacific were fluctuating in phase... (D'après résumé d'auteur