René Funes-Rodríguez

Influences of El Niño on assemblages of mesopelagic fish larvae along the Pacific coast of Baja California Sur

Abstract Seasonal assemblages of mesopelagic fish larvae and changes related with environmental factors (plankton biomass, sea surface temperature anomaly, upwelling, and the multivariate El Niño index) were investigated. From 1982 to 1987, 16 oceanographic cruises were carried out along the Pacific coast of Baja California Sur, Mexico. Larvae of 42 mesopelagic fish taxa were collected. Larval abundance was highly variable during the studied period, but summer months coincided with higher abundance (>200 larvae under 10 m2). Larval assemblages were dominated by three of the most common species of tropical (Vinciguerria lucetia, Diogenichthys laternatus) and subtropical affinity (Triphoturus mexicanus). A group of species of tropical affinity (Diplophos proximus, Diaphus pacificus, Benthosema panamense) was useful for distinguishing the 1982–84 El Niño event, and an assemblage of larvae of temperate affinity (Symbolophorus californiensis, Melamphaes lugubris, Bathylagus ochotensis, Leuroglossus stilbius, Protomyctophum crockeri) characterized ‘normal’ years (mid‐1984 to mid‐1987).

Interannual distribution of Pacific hake Merluccius productus larvae in the southern part of the California Current

The interannual distribution of early life stages of Pacific hake Merluccius productus, within the southern part of the California Current (32-23 degrees N) from 1951 to 2001, was examined to describe the relationship between spawning habitat and environmental conditions. Mean annual abundance was affected by different factors along the west coast of the Baja California Peninsula. In the northern areas (Ensenada and Punta Baja), reduced abundance of larvae coincided with the El Niño and a North Pacific Ocean climatic regime shift, but in the southern areas (San Ignacio to Bahía Magdalena), the drastic reductions suggested a fishery effect for large adults of the coastal migratory population, starting in 1966. Two spawning stocks, coastal and dwarf, were evident in comparisons of latitudinal differences in occurrence of early stages and differences in temperature preferences that seemed to break at Punta Eugenia.

Influence of hydrographic conditions on larval fish assemblage structure in the northern Gulf of California

This paper analyzes the seasonal variability on larval fish assemblage structure and the relationships to hydrographic conditions during 4 seasonal surveys i...

Larval abundance variation of Bregmaceros cantori Milliken & Houde, 1984, related to the El Niño events (1987-1996), southern Gulf of Mexico

Se analiza la influencia de El Nino Oscilacion del Sur (ENSO) sobre la variacion de la abundancia de las larvas del pez Bregmaceros cantori en el sur del Golfo de Mexico. El estudio se desarrollo entre 1987 y 1996, usando 20 cruceros oceanograficos. La abundancia de B. cantori fue relacionada con: (1) la anomalia de la temperatura superficial del mar (SSTA) del Oceano Pacifico central ecuatorial, (2) la temperatura promedio de la capa superficial de 30 m, de datos de las campanas, (3) las descargas de aguas continentales con datos provenientes de la estacion hidrologica mas cercana al area de estudio. Hubo una alta variabilidad de la abundancia de larvas de B. cantori a traves del tiempo, pero no se registro un patron estacional. Durante el periodo de estudio ocurrieron tres eventos de El Nino: 1987, 1992 y 1995. Los analisis estadisticos indicaron diferencias significativas en la abundancia de larvas entre los anos de El Nino y anos normales, sin el evento de El Nino. Se encontraron altas abundancias de B. cantori en los periodos de El Nino en comparacion con los anos normales. Es posible que las mayores abundancias de larvas de B. cantori durante anos de El Nino esten asociadas con relaciones depredador-presa

Comparison of pteropod assemblages and their relationship with environmental variables in the southern Gulf of Mexico

A comparison of pteropod assemblages and their relationship with environmental factors in the southern coastal and oceanic zones of the Gulf of Mexico (GM) was performed during the springs (May–June) of 2006 and 2010. Zooplankton samples came from catches of 136 oblique tows with a Bongo net (0.61 m in mouth diameter; mesh 505 μm) and included 20 species of Euthecosomata, six of Pseudothecosomata, and three species and three genera of Gymnosomata. Four new records were found for the area (Diacavolinia strangulata, Cymbulia sibogae, Paraclione longicaudata and Thliptodon diaphanus). The most abundant species were Creseis conica, Limacina trochiformis and Creseis acicula, followed by Heliconoides inflatus. Pteropod abundance was higher in the neritic zone, particularly in the area of the epicontinental water discharge at the coastal front of the Veracruz-Tabasco zone, while higher diversity was observed in the oceanic zone. The cluster analyses and canonical correspondence analyses showed two assemblages (station groups) in each period: Oceanic and Coastal. The Oceanic assemblage was composed of species of oceanic origin with two indicator species (H. inflatus and Limacina lesueurii). This assemblage was correlated with increased sea surface temperature, at least during 2006, probably modulated by the influence of the Loop Current. The Coastal assemblage included both oceanic and neritic species and was subdivided into three, geographically distinct, station zones: (1) Veracruz-Tabasco zone characterized by Desmopterus papilio and L. trochiformis, their abundances inversely correlated with salinity and increased CO2, and influenced by river discharges and the narrow continental shelf; (2) Yucatan zone characterized by C. conica as an indicator species (2006); and (3) Confluence zone characterized by C. acicula (Laguna de Términos). Yucatan and Confluence zones were characterized by elevated pH, and reduced turbidity and temperature, at least during 2010.

Identificación de zonas propicias para el desarrollo larval de la macarela del Pacífico(Scomber japonicus) en la porción sur de la Corriente de California

espanolEl tamano larval es una variable importante para entender los cambios en el desarrollo y la identificacion de un entorno adecuado para el crecimiento y la supervivencia larval. Las larvas de la macarela del Pacifico (Scomber japonicus) presentan un lento crecimiento durante las primeras fases del desarrollo (6-8 mm de LE); posteriormente, la velocidad de crecimiento aumenta, pero el desarrollo depende principalmente de la temperatura y del alimento. El objetivo del presente trabajo fue identificar las zonas y temporadas propicias para el desarrollo larval de S. japonicus, en relacion a la temperatura superficial del mar y la biomasa del zooplancton, frente a la costa occidental de la Peninsula de Baja California (~25-32°N) del 2006 al 2010. Las larvas de la macarela del Pacifico mostraron la mayor amplitud en su distribucion espacial en primavera, pero con mayor abundancia restringida frente a Punta Eugenia (~28°N) durante el verano. Los cambios en su distribucion, estuvieron bajo la influencia del flujo geostrofico y la variabilidad termica. El analisis de regresion lineal permitio identificar zonas propicias para el desarrollo de larvas, con un menor desarrollo en primavera, relacionado con un intervalo estrecho de temperaturas y niveles de biomasas del zooplancton comparativamente bajos. En contraste, durante el verano el mayor incremento en la altura del cuerpo (s) fue relacionado con un amplio intervalo de temperaturas, mientras que su baja variabilidad (error estandar) coincidio con altos niveles de biomasa del zooplancton. Se considera que las condiciones termicas y de disponibilidad de alimento favorecen un optimo desarrollo larval particularmente en la epoca de verano. EnglishLarval size is considered as an important variable to understand the changes in larval development and identification of a suitable environment for larval growth and survivor. Larvae of the Pacific mackerel (Scomber japonicus) have a slow growth during the early stages of development (6-8 mm SL); subsequently, the growth rate increases, but the development depends mainly on the temperature and food. The aim of this study was to identify the areas and seasons favorable for larval development of S. japonicus, in relation to the sea surface temperature and the zooplankton biomass, off the west coast of the Baja California Peninsula (~25°-32°N) from 2006 to 2010. Larvae of the Pacific mackerel showed the greatest amplitude in their spatial distribution during spring, but with greater restricted abundance compared to Punta Eugenia (~28°N) during summer. Changes in its distribution were influenced by geostrophic flow and thermal variability. Linear regression analysis allowed to identify areas favorable for larvae development, with a lower development in spring, related to a narrow range of temperatures and levels of comparatively low zooplankton biomass. In contrast, during summer the largest increase in body height (s) was related to a wide range of temperatures, while its low variability (standard error) coincided with high levels of zooplankton biomass. It is considered that thermal conditions and food availability, favor an optimum larval development, particularly during the summer season.

Spatiotemporal variability of demersal fish larvae assemblages in the southern region of the California Current

ABSTRACT An analysis was conducted of the community structure variability of demersal fish larvae and its relationship with environmental forcing on the west coast of the Baja California Peninsula (25–31°N). The information comes from two data sets of oceanographic cruises in 1997–2000 and 2006–2010. From a total of 190 identified taxa, a high number of species (71) was shared throughout the peninsula. The spatiotemporal contrast in the community structure suggests the separation of two groups (northern and southern) whose boundary is located around Punta Eugenia. The northern group showed an alternate dominance of species with a subarctic-transitional faunistic affinity during the winter and spring and species of a subtropical affinity during summer–autumn. In contrast, the dominant taxa in the southern group have a tropical–subtropical affinity throughout the year, although some taxa of subarctic-transitional affinity also occur during winter–spring. In the spatiotemporal scale, these results suggest that the major cause that modulates the extension and structure of the assemblages is the seasonal oceanic dynamics. Moreover, the intensity of warming or cooling events (El Niño and La Niña) influences the structure of the community on an interannual scale by displacing the zonal boundaries of the groups’ distribution.

Influence of Hydrographic Conditions on the Distribution of Spiny Lobster Larvae off the West Coast of Baja California

AbstractThe distribution of phyllosoma of California spiny lobster Panulirus interruptus was investigated in relation to the seasonal variability of hydrographic conditions off the west coast of the Baja California Peninsula between 2006 and 2008. Early larval stages were recorded mostly from summer to fall, immediately following the reproductive period. The duration of larval development in plankton is variable (8–12 months), and hence, larvae are found at different times of the year; thus, intermediate and late stages did not show a well-defined seasonal pattern. The highest phyllosoma density was associated with the relatively warm transitional water mass. However, the peak frequency of occurrence was observed in the colder subarctic water mass. A canonical correspondence analysis identified two distinct seasonal periods: (1) a warm period (summer–autumn), when the abundance of early and intermediate stages was highly correlated with a higher sea surface temperature, and (2) a cold period (winter–sprin...