Connectivity of coastal and neritic fish larvae to the deep waters

Four ichthyoplankton cruises and backward tracking experiments were conducted to study the connectivity of coastal and neritic fish larvae over the continental slope and to the oceanic deep-water region of the western Gulf of Mexico. Distribution patterns of larval abundance at oceanic stations showed higher abundance and the presence of larvae at oceanic stations during two cruises. Larval transport was simulated using outputs of a data assimilation model that represented the flow conditions during each cruise. Higher abundances of larvae of coastal and neritic species at oceanic stations agreed with offshore transport inferred from numerical experiments seeding particles over different spatial scales (stations vs. transects). Satellite images of surface chlorophyll were consistent with the circulation patterns indicated by the model, indicating filaments of shelf waters were transported toward the transects with higher larval abundances. Particle tracking experiments indicated that the northwestern shelf provinces of Perdido, Tamaulipas, and Texas were the main source of propagules to the oceanic region, while shelf provinces of northern Veracruz, Campeche, Yucatan, Louisiana, and Mississippi-Alabama contributed much less. The length and intensity of the shelf front limited ichthyoplankton cross-shelf exchange during some cruises, and mesoscale anticyclonic and cyclonic eddies advected larvae to the deep-water region during others. The agreement between the spatial distribution of fish larvae and the simulated larval transport confirm that circulation models are a valuable tool for examining potential dispersal pathways of neritic species, as long as similar spatial and temporal scales as the ones used in this study are considered.Fil: Cano Compaire, Jesus. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; Argentina. Consejo Nacional de Ciencia y Tecnología de México. Centro de Investigación Científica y de Educación Superior de Ensenada Baja California; MéxicoFil: Pérez Brunius, Paula. Consejo Nacional de Ciencia y Tecnología de México. Centro de Investigación Científica y de Educación Superior de Ensenada Baja California; MéxicoFil: Jiménez Rosenberg, Sylvia Patricia Adelheid. Instituto Politécnico Nacional. Centro Interdisciplinario de Ciencias Marinas; MéxicoFil: Rodríguez Outerelo, Javier. Consejo Nacional de Ciencia y Tecnología de México. Centro de Investigación Científica y de Educación Superior de Ensenada Baja California; MéxicoFil: Echeverri García, Laura del Pilar. Consejo Nacional de Ciencia y Tecnología de México. Centro de Investigación Científica y de Educación Superior de Ensenada Baja California; MéxicoFil: Herzka, Sharon Z.. Consejo Nacional de Ciencia y Tecnología de México. Centro de Investigación Científica y de Educación Superior de Ensenada Baja California; Méxic

Descripción del desarrollo larvario de Eucinostomus gracilis y larvario y juvenil de Eucinostomus dowii y Diapterus peruvianus.

Impreso y PD

Indicadores biológicos en el ambiente pelágico

La evaluación de los ecosistemas con respecto a su nivel estabilidad y las causas de su cambio son elementos indispensables para el manejo y regulación de sus recursos. Para tal efecto, los indicadores biológicos se han convertido en un componente vital ya que están diseñados para proveer señales sobre eventos a gran escala que ocurren en el ambiente y hacer perceptibles tendencias o fenómenos no detectables fácilmente. Sin embargo, se deben tomar ciertas consideraciones en la selección y el uso de los indicadores biológicos adecuados y entender que estos no deben de ser empleados como sustitutos de otros procedimientos de evaluación ambiental e investigación. En el ambiente marino pelágico, comunidades y organismos de diferentes niveles tróficos han mostrado su utilidad como indicadores biológicos, sin embargo el valor de la información que aportan está en función de la posibilidad de ser extrapolada a diferentes escalas de espacio y/o tiempo, así como de la experiencia y objetividad del investigador. La obtención de series de tiempo larga proveniente de las pesquerías y programas de investigación diversos, (muchos de ellos enfocados a las comunidades planctónicas), ha mostrado su utilidad para ser utilizadas como indicadores biológicos. En consecuencia, la mayoría de la investigación encaminada a conocer la variabilidad ambiental se enfoca en estos organismos

Larval, pre-juvenil and juvenil development of Diapterus peruvianus (Perciformes: Gerrreidae)

The development of Diapterus peruvianus (Sauvage 1879) is based on 60 larvae collected in superficial tows made in Bahía Concepción, and on 16 prejuvenile and juvenile organisms collected in Bahía de La Paz, B. C. S., México, using a standard plankton net and a rectangular epibenthonic net, respectively. Larvae of D. peruvianus show three large blotches on the dorsum of the gut that can fuse together and give the appearance of one large continuous blotch. There are two to three pre-anal pigments and 16 post-anal pigments in the ventral midline; cephalic pigments are present from the postflexion stage, as well as a serrated preoperculum. The prejuvenile and juvenile organisms are distinguished by their body depth, the analfin formula, the serrated preoperculum and the base pigments in the dorsal and anal fins

Larval, pre-juvenile and juvenile development of Diapterus peruvianus (Perciformes: Gerreidae)

The development of Diapterus peruvianus (Sauvage 1879) is based on 60 larvae collected in superficial tows made in Bahía Concepción, and on 16 prejuvenile and juvenile organisms collected in Bahía de La Paz, B. C. S., México, using a standard plankton net and a rectangular epibenthonic net, respectively. Larvae of D. peruvianus show three large blotches on the dorsum of the gut that can fuse together and give the appearance of one large continuous blotch. There are two to three pre-anal pigments and 16 post-anal pigments in the ventral midline; cephalic pigments are present from the postflexion stage, as well as a serrated preoperculum. The prejuvenile and juvenile organisms are distinguished by their body depth, the analfin formula, the serrated preoperculum and the base pigments in the dorsal and anal fins.El desarrollo de Diapterus peruvianus se analizó con base en 60 larvas recolectadas en Bahía Concepción y 16 pre-juveniles y juveniles recolectados en la Ensenada de La Paz, B. C. S. México, usando respectivamente, una red estándar de plancton en arrastres superficiales y una red epibentónica para arrastres de plancton. Las larvas presentan desde la pre-flexión tres manchas alargadas sobre la superficie dorsal de la masa visceral, que pueden unirse y dar apariencia de pigmentación continua, observándose hasta 16 pigmentos post-anales en la línea media ventral y de dos a tres pigmentos pre-anales; la pigmentación cefálica así como la forma aserrada del pre-opérculo característica del género, aparecen a partir de la post-flexión. Los organismos pre-juveniles y juveniles se distinguen por la profundidad del cuerpo, la fórmula de la aleta anal, la fina forma aserrada del pre-opérculo y la pigmentación en la base de las aletas dorsal y anal

Distribution and abundance of fish larvae in Bahia de La Paz, (Gulf of California) and their relation to hydrographic variability during summer (1997-1998)

Bahía de La Paz, the largest coastal bay in the Gulf of California, is characterized by high diversity of fish species, mainly during summer and autumn. Distributions and abundances of fish larvae in the bay were analyzed and compared with zooplankton, CTD, current and satellite data obtained in July 1997 and August 1998. Larval abundance (>4000 larvae per 100 m3) and number of species (>90 species) were high during both cruises. The Bray-Curtis dissimilarity index was used to define three station groups. The "Coastal" group, with the highest abundance and number of species, was located mainly in the shallow basin of the bay (<30 m depth). Larval Gerreidae (e.g. Eucinostomus gracilis, E. dowii, and Diapterus peruvianus) and Pomacentridae (Abudefduf troschelii and Stegastes rectifraenum) were the most abundant taxa in this station group, but larval Mullidae (Mulloidichthys dentatus) also were abundant in August 1998. This station group was associated with the highest zooplankton biomass and lowest sea-surface temperature as a result of mixing by the winds and tidal currents that affect this shallow zone. The "Central-A" station group, located in the central bay, and the "Central B" group situated nearby, had low larval abundance and number of species. These station groups coincided with the lowest zooplankton biomass and highest sea-surface temperature in both summers, and with the location of a cold gyre at 50 m depth in July 1997. These conditions are influenced by the water entering from the Gulf of California through the main mouth of the bay (>100 m), resulting in a wide central zone with low larval abundance during both summers

Fish larvae in Bahía Sebastian Vizcaíno and the adyacent oceanic region, Baja California, México

The taxonomic composition of the fish larvae assemblage of Bahía Sebastián Vizcaíno and the adjacent oceanic region is presented based on oblique zooplankton hauls made during 12 oceanographic surveys between fall 1997 and fall 2000. In total, 186 taxa representing 71 families were collected. Myctophidae, Phosichthyidae, and Engraulidae were the most abundant during winter and Myctophidae, Merlucciidae, and Bathylagidae during spring. In summer and fall Phosichthyidae and Myctophidae were the most abundant. During 1999 and 2000, seasonal variability was identified in the area by the fish larvae composition, defining winter and fall as a low diversity period and spring and summer as a high diversity period. Interannual variability was detected with an El Niño event, with higher larval abundances of tropical and subtropical taxa, and a La Niña event, with high abundances of larvae of Engraulis mordax