Aspectos particulares de la maduración gonádica y talla de primera madurez de Atrina maura (Bivalvia: Pinnidae)

The gonadal maturation of Atrina maura was examined by means of histological analysis and quantitative criteria. Particular features not previously described for this species are reported in this study: in both males and females the undifferentiated stage is absent and there is massive gamete resorption when the seawater temperature reaches 25°C; in males, there is continuous spawning concurrent with other gonadal development stages and the adipogranular cells surrounding the acini walls decrease with testis ripeness, which suggests they play an energetic role. Atresia displayed two stages: cytoplasmic structures with oocyte degeneration and digestion by hemocytes. The oocyte diameter was larger than that reported for cultured specimens. Size at first maturity was reached at 23.3 cm in shell height (SH) (12.2 cm in shell length, SL) in females and 22.8 cm SH (12.0 cm SL) in males.Se analizó histológicamente y usando criterios cuantitativos el proceso de maduración gonádica de Atrina maura. Se reportan características particulares que no han sido descritas previamente para la especie: ausencia de la fase de indiferenciación y reabsorción masiva de gametos, tanto en hembras como en machos, cuando la temperatura del agua alcanza los 25°C; en los machos presencia de eyaculación continua simultánea con otras fases de desarrollo gonádico y células adipogranulares arregladas alrededor de las paredes de los acinos que disminuyen conforme avanza la maduración, sugiriendo un papel energético. La atresia presentó dos fases: estructuras citoplasmáticas con degeneración ovocitaria y digestión por hemocitos. El diámetro de los ovocitos fue mayor que los reportados para organismos de cultivo. La talla de primera madurez para las hembras se estableció en 23.3 cm de altura de la concha (AC) (12.2 cm de longitud de la concha, LC) y para los machos en 22.8 cm de AC (12.0 cm de LC)

Contribución a la biología de los cangrejos araña Maiopsis panamensis y Stenocionops ovata (Decapoda: Majoidea) del Golfo de California, México

Se presentan datos morfológicos de los cangrejos araña Maiopsis panamensis y Stenocionops ovata obtenidos a partir de capturas incidentales realizadas en el Golfo de California. Se informan proporciones de sexo, distribuciones de talla por sexo, valores de anchura y longitud del caparazón, distribuciones de peso por sexo, y frecuencia de hembras ovígeras. Se observaron valores de la talla del ancho branquial superiores a aquéllos citados anteriormente para organismos machos de ambas especies: M. panamensis, 70 mm más ancho y S. ovata, 9.5 mm más ancho. Por otra parte, se registra la presencia de M. panamensis a lo largo de la costa occidental del Golfo de California (25°48�54"N 111°15'45"W), fuera de su límite de distribución conocido

Ciclo reproductivo del pargo lunarejo Lutjanus guttatus (Steindachner, 1869) en las costas de Guerrero, México.

Se estableció el ciclo reproductivo del pargo lunarejo Lutjanus guttatus, un pez de gran importancia comercial. Los organismos se recolectaron mensualmente desde febrero de 1993 a diciembre de 1994. La proporción de sexos poblacional fue de 1M:0.96H y no se encontró una diferencia significativa (P£0,05) de la proporción esperada de 1:1. Las gónadas se analizaron histológicamente y se describieron las fases de desarrollo gonadal. L. guttatus presenta un desarrollo asincrónico de las gónadas y es un desovador parcial. La actividad reproductiva estuvo presente todo el año aunque con dos períodos reproductivos principales (marzo-abril y agosto-noviembre) representados por altos porcentajes de gónadas categorizadas como maduras y en desove. Estos períodos coinciden con valores elevados del índice gonadosomático (IGS) y valores bajos del índice hepatosomático (IH). El factor de condición (FC) presentó una tendencia similar a la del IGS con los máximos valores durante la época de reproducción y disminuyendo hacia las épocas de reposo. Se considera que el IGS representa adecuadamente la actividad reproductiva y que puede haber una relación inversa entre la actividad reproductiva y el IH

Comparative analysis of the reproductive strategy of lion's paw scallop Nodipecten subnodosus in Baja California Sur, Mexico

The reproductive strategy of lion's paw scallop Nodipecten subnodosus was evaluated in a culturing system in Bahía Tortugas, Baja California Sur, Mexico during an annual cycle, comparing its response with data previously reported at other localities. High frequencies of ripe gonads throughout the year indicate that reproduction was continuous, with two main ripening/spawning events: July-September and December-March. A continuous breeding is also reported for the species in Bahía Magdalena, Bahía Juncalito, and Bahía de Los Angeles. These eutrophic areas are Biological Active Centers where gametogenesis appears to be regulated by the energy taken from recently ingested food following an opportunistic strategy. However, the digestive gland index decreased and the muscle indices increased during one of the breeding peaks, suggesting that some stored reserves are also used to sustain gametogenesis (conservative strategy) partially. High incidences of atretic oocytes are likely associated with atypical daily variations in water temperature from May through September (12 to 33°C), or with stressful conditions in the culturing system in summer. Despite this, the culturing system set in Bahía Tortugas appears beneficial for a continuous reproduction of N. subnodosus

Reproductive aspects of Sphoeroides annulatus (Jenyns, 1842) (Tetraodontiformes, Tetraodontidae) inhabiting the Mazatlan coast, Sinaloa, Mexico

La muestra de Sphoeroides annulatus capturada en la costa de Mazatlán, Sinaloa, México fue predominantemente de adultos, como resultado de una aparente distribución diferencial por talla/edad de la especie. La proporción sexual fue 1:1. Las hembras presentaron un crecimiento alométrico y los machos, isométrico. De acuerdo con el análisis morfocromático de las gónadas, la época de reproducción es en abril-mayo y octubre-noviembre, aunque los machos presentan madurez durante periodos más amplios. El IGS sí es un buen indicador de la época de reproducción de S. annulatus, mientras que el Kn muestra una tendencia a disminuir durante el periodo de reproducción

Life histories predict genetic diversity and population structure within three species of octopus targeted by small-scale fisheries in Northwest Mexico

The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species targeted by artisanal fisheries in the region with distinct life histories, the lack of basic biological information about the distribution, metapopulation size and structure of each species could impede effective fisheries management to avoid overexploitation. We tested if different life histories of three species of octopus could help predict observed patterns of genetic diversity, population dynamics, structure and connectivity and how this information could be relevant to the sustainable management of the fishery. We sequenced two mitochondrial genes and genotyped seven nuclear microsatellite loci to identify the distribution of each species in 20 locations from the Gulf of California and the west coast of the Baja California peninsula. We tested five hypotheses derived from population genetic theory based on differences in the fecundity and dispersal potential for each species. We discovered that Octopus bimaculoides with low fecundity and direct development (without a planktonic phase) had lower average effective population size and genetic diversity, but higher levels of kinship, population structure, and richness of private alleles, than the other two species. These features indicated limited dispersal and high local recruitment. In contrast, O. bimaculatus and O. hubbsorum with higher fecundity and planktonic phase as paralarvae had higher effective population size and genetic diversity, and overall lower kinship and population structure than O. bimaculoides. These observations supported higher levels of gene flow over a larger geographical scale. O. bimaculatus with the longest planktonic paralarval duration and therefore larger dispersal potential had differences in the calculated parameters possibly associated with increased connectivity. We propose O. bimaculoides is more susceptible to over exploitation of small, isolated populations and could have longer recovery times than the other two species. This species may benefit from distinct fishery management within each local population. O. bimaculatus and O. hubbsorum may benefit from fishery management that takes into account metapopulation structure over larger geographic scales and the directionality and magnitude of larval dispersal driven by ocean currents and population connectivity among individuals of each locality. The distribution of each species and variations in their reproductive phenology is also important to consider when establishing marine reserves or seasonal fishing closures.Secretaria de Investigacion y Posgrado projects [20120971, 20121594, 20130059, 20130089, 20140781, 20140465, 20150998, 20150117]; CONACyT [108230]; institutional fund CONACyT Fronteras de la Ciencia [292/2016]; Consejo Nacional de Ciencia y Tecnologia [328943, 291053, 2016-1]; PANGAS [2013-39400, 2015-62798]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]