Hidrobiológica (E-Journal)
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Shallow water hippolytid shrimps (Crustacea: Decapoda: Caridea) from the Mexican Caribbean coast
Get PDFA checklist of shallow water shrimps of the family Hippolytidae of the central-southern coast of the Mexican Caribbean is presented. A total of 11 species belonging to 6 genera were collected on beds of Thalassia testudinum in Bahía de la Ascensión, Bahía del Espíritu Santo, and the Mahahual reef lagoon, Quintana Roo, Mexico. Genera Hippolyte and Thor were the most diverse with three species each. An updated geographic distribution along the western Atlantic and other regions is provided for all the species. Outside of the Caribbean province, greatest affinity of the hippolytid fauna is with the Virginian, Carolinian, Texan, and Brazilian provinces. New regional records are given and the occurrence of Hippolyte pleuracanthus is cited for the first time in the Mexican Caribbean
Planktonic crustacean assemblages of three reservoirs from the Mexican Central Plateau: relationships with biotic and abiotic factors
Get PDFThe reservoirs Trinidad Fabela (TF), Ignacio Ramírez (IR) and Tepuxtepec (T) are located along an altitude gradient in the upper Lerma Basin of the Mexican Central Plateau. Between July 1993 and June 1994, the planktonic crustacean assemblages of these systems were dominated by seven cladoceran species and five copepod species. Specific richness ranged from 13 species in TF to 16 species in T, out of a total 20 species. Nine species were common to all three systems, while the rest were absent from at least one reservoir. Canonic correspondence analysis showed that the structure and seasonal variation of these assemblages are regulated by factors directly related (transparency and dissolved oxygen) or inversely related (turbidity, temperature, mineralization and eutrophication) to the altitude at which the reservoirs are located. TF had the lowest levels of mineralization and the lowest specific richness, as well as the highest plankton diversity and mean density, while T had the highest mineralization and highest specific richness, but showed the lowest density. Crustacean mean size was smaller in T than in TF, possibly due to predation by fish in the former system and the presence of fish predators (waterfowl) in the latter, as well as the impact of the different hydrological regime and release schedules of the reservoirs
Obtención de una fracción con actividad gonadotrópica de la hipófisis de la tilapia Oreochromis noiloticus (Osteichtyes: Cichlidae)
No full textGonadotrophic hormone was isolated from pituitary of tilapia through out Sephadex G-100 chromatography and posterior comprobation by electrophoretic poliacrilamide gel. One fraction had similar electrophoretic mobility to follicle-stimelating hormone, and its molecular weight was calculated as 32 000 Da. Biological activity of the molecule on that fraction was tested through a bioassay with juvenile male and female carps, which gonadal development was more advanced compared with the gonadal development of the fish that were treated with luteinizing hormone of mammals, gonadolac and control group.Se aisló la hormona gonadotrópica a partir de hipófisis de la tilapia, por medio de cromatografía en Sephadex G-100. Se comprobó esto al observarse una banda por medio de electroforesis en geles de poliacrilamida. Una fracción presentó un patrón de movilidad electroforética similar al de la hormona folículo estimulante de mamíferos y su paso fue calculado en 32 000 Da. Posteriormente se comprobó que la molécula contenida en dicha fracción poseía actividad biológica por medio de un bionsayo con capras macho y hembras, que presentaron un mayor desarrollo gonadal en comparación con gónadas de peces tratados con hormona luteinizante de mamífero, gonadolac y del grupo control
Effect of oral treatment of synthetic androgens on sex ratio, survival and growth rates, in three strains of tilapia
No full textThe effect of dietary administration of the synthetic androgens 17 ?-methyltestosterone MT (40 mg), luoxymesterone FM (1 mg) and propionate testosterone PT (50 mg) per kg of feed, on Stirling strain (Oreochromis niloticus, Linnaeus, 1757), Red strain (Oreochromis niloticus, Linnaeus, 1757) and the hybrid Rocky Mountain (Oreochromis niloticus, Linnaeus, 1757 x Oreochromis aureus, Steindachner, 1864) fry, was evaluated during a 30 day trial to induce sex reversal. The most efficient androgen was MT for male ratio (92%), mean percentage survival and specific growth rate. TP was th least efficient (67 % male). The percentage of males from FM treatment was 80.6%, but this can be improved when time period or hormone-treated dosage are increased. Thus, the FM androgen could be recommended for a successful sex reversal, instead of MT. The Stirling strain (O. niloticus) had the best results when compared to the other two strains of tilapia
Antibiotics incorporation in Artemia franciscana nauplii, metanauplii, juveniles and adults, and their inhibitory action on Aeromonas hydrophila bacteria
Get PDFThe crustacean Artemia franciscana has been used as a drug carrier, mainly in its nauplius stage; however, the use of other developmental stages, i.e., metanauplius, juvenile, and adult, potentially allows treating diseases not only in fry but also in juveniles and adults. In the present work, we studied the incorporation of antibiotics in these stages to inhibit the growth of the bacterium Aeromonas hydrophila, which causes a high mortality in freshwater fishes. The antibiotics used were: chloramphenicol (base antibiotic), nitrofurantoin (Macrodantina®, 50 mg capsules) and ciprofloxacin (Ciproflox®, 250 mg capsules). Four wells were made in Petri dishes with Trypticase® soybean agar (TSA) and 2 mL of bacterial inoculum. The wells were used for each antibiotic and one for the control. A 1- mL sample of each Artemia stage, incorporated with an antibiotic, was placed in each well and incubated for 24 h at 37°C, measuring the inhibition halos thereafter. Results indicated that 4 h are needed for the nauplii to become saturated and for the metanauplii, juveniles, and adults to fill their digestive tract with the antibiotic. In nauplii, the three antibiotics produced inhibition halos; in metanauplii, ciprofloxacin produced the best result (22.57 mm); in juveniles, chloramphenicol (38 mm) and ciprofloxacin (33 mm) gave the best results; in adults, the best results were obtained also with chloramphenicol (33 mm) and ciprofloxacin (40 mm). Nitrofurantoin did not yield positive results in metanauplii, juveniles, and adults, and because it is soluble in water, it is recommended to apply it in lipidic solutions to ease its incorporation. Results from this study allow us to establish the bases for the control and treatment of infectious diseases caused by the bacterium Aeromonas hydrophila through the use of commercial antibiotics, easily available in Mexico
On the description of Brachionus araceliae sp. nov. A new species of freshwater rotifer from Mexico
Get PDFThis contribution describes a new species of Brachionus distinguished of the other species of the genus for the presence of two prominent posterior wing-like structures. These structures were previously recorded in Brachionus bidentatus Anderson 1899 var. ambidentatus De Ridder 1991. However, De Ridder assumed that these structures were induced by an environmental factor and then named it as a variety. This work demonstrates that this rotifer deserves species status based on: 1) the general morphology of the female with six anterior spines with a distinctive pattern different to all known Brachionus bidentatus varieties, and the two prominent posterior wings that represent permanent structures in all females (B. araceliae has been cultivated under constant conditions in the laboratory and the wings have been preserved beyond the fifth generation); 2) the morphology of the male of B. araceliae is different of that of the B. bidentatus male
Impact of two decades of shellfish farming on phytoplankton biomass, abundance and productivity of a coastal lagoon influenced by upwelling
Get PDFLong-term impact of the Pacific oyster Crassostrea gigas farms on the phytoplankton biomass as chlorophyll a concentration (chl-a), abundance and productivity (PP) of the western arm of Bahía San Quintín (Falsa Bay), a coastal lagoon influenced by the California Current coastal upwelling, was evaluated after two decades of commercial cultures. High-resolution time series (on an hourly basis) of these variables were generated in 1999 and 2000, for locations with and without oyster cultures in Falsa Bay. Representative averages of these data were compared with data reported for 1979, when the commercial cultures were just starting. Also, data of 1979 and recent data were used separately to explore possible short-term (hourly) effects of oysters on the phytoplankton variables. The available data are scarce and do not support the hypothesis of diminished phytoplankton biomass, abundance and PP due to the oyster cultures. In general, there were no statistically significant differences between the averages of chl-a (2.5 mg m-3 ), microphytoplankton abundance (from 42·103 to 194·103 cells L-1, depending upon the location) and PP (12 mgC m-3 h-1 ) when comparing 1979, and 1999 - 2000 data. This was possibly due to the relatively low residence time of Falsa Bay waters (~8 days) and relatively low oyster density (a total of ~900 tons, with an estimated maximum carrying capacity from ~2,000 to 6,000 tons for this arm of the bay)
Cultivo de ostión Crassostrea gigas: Análisis de 40 años de actividades en México
Get PDFThis study is the revision of the culture of the oyster Crassostrea gigas since its introduction in Mexico 40 years ago. The introduction occurred in Baja California during 1973 and then the cultures expanded to other states. There is no juvenile collection from the wild so the spat is produced in national and foreign hatcheries. Current culture systems are; hanging oysters fixed on ropes from racks, oyster trays in long-lines, and plastic mesh bags set on trestles. Mortality outbreaks have been detected since 1997 and today is known that events occur in March-April and November affecting oysters less than 50 mm long. Two diseases related to mortality outbreaks have been confirmed for C. gigas in Mexico; herpesvirus and perkinsosis. Production collapsed due to mortalities leading to a crisis of the activity; signs of recovery are seen until 2010 with a production of 2,858 tonnes. Aquatic animal health agencies as well as state oyster committees in Baja California, Baja California Sur, and Sonora have been key elements for the recovery and organization of oyster industry in the region. At present, studies in genetics are in course to produce disease-resistant oysters and there are promising results using new experimental culture systems. However, problems associated with the activity are diverse and require important efforts from all sectors involved to consolidate the cultivation of the species in the region.Se presenta una revisión sobre el cultivo del ostión Crassostrea gigas desde que fue introducido a México hace 40 años. La introducción de esta especie se hizo en Baja California durante 1973 y a partir de ahí el cultivo de la especie se extendió a otros estados. No hay captación natural de la especie en la región; toda la semilla que se utiliza proviene de laboratorios nacionales y extranjeros. Los principales sistemas de cultivo son; sartas en balsas y estantes, cajas ostrícolas en sistema suspendido y costales sobre estantes. En 1997 se empezaron a registrar mortalidades masivas de ostión y actualmente se sabe que los eventos ocurren en marzo-abril y noviembre, afectando principalmente a ostiones menores de 50 mm. Se han confirmado dos enfermedades para C. gigas en México relacionadas con las mortalidades; herpesvirus y perkinsosis. Debido a las mortalidades la producción se desplomó y puso en crisis a la actividad; hasta 2010 se empiezan a ver signos de recuperación (2,858 toneladas). Los Comités de Sanidad Acuícola así como los Comités Estatales Sistema Producto Ostión en Baja California, Baja California Sur y Sonora han sido claves para la recuperación y organización de la ostricultura en la región. Actualmente se realiza investigación en genética para producir ostiones resistentes a enfermedades y se tienen resultados alentadores usando nuevas tecnologías de cultivo. No obstante, las problemáticas asociadas a la actividad son variadas y se requieren esfuerzos importantes de todos los sectores involucrados para consolidar el cultivo de la especie en la región
Relación peso-longitud de Labidocera diandra y Labidocera johnsoni (Calanoida: Pontellidae)
Get PDFThe length weight relationship of the pontellid copepods Labidocera diandra and L. johnsoni was estimated in a coastal lagoon of the southeastern Gulf of California, Mexico. The equation that describes the relationship for L. diandra is W = 9.564e0.92PL(mm) (r2 = 0.83, p< 0.05) and for L. johnsoni is W = 103.95e0.06PL(mm) (r2 = 0.01, p > 0.05); L. diandra had the greatest weight and size variation. The condition factor in both species had a significantly negative trend respect to size, being more pronounced in L. johnsoni. The equations representing the weight-length relationship of pontellid copepod species are indicators of the species biomass and are useful for estimating the rate of secondary production in ecosystems with different levels of anthropogenic intervention.La relación peso-longitud y el factor de condición de los copépodos pontélidos Labidocera diandra y L. johnsoni, fue estimada en una laguna costera del sureste del Golfo de California, México. La ecuación que describe la relación para L. diandra es W = 9.564e0.92PL(mm) (r2 = 0.83, p< 0.05) y para L. johnsoni es W = 103.95e0.06PL(mm) (r2 = 0.01, p > 0.05), con la mayor variación de peso y talla en L. diandra. El factor de condición en ambas especies tuvo una tendencia significativamente negativa respecto a la talla, siendo más pronunciada para L. johnsoni. Las ecuaciones que representan la relación peso-longitud de especies de copépodos pontélidos, son indicadoras de la biomasa de las especies y son útiles para estimar la tasa de producción en ecosistemas con distinto nivel de intervención antropogénica
Distribución y abundancia de Parastichopus parvimensis (Holothuroidea) en islas de la costa occidental de Baja California Sur, México, durante el periodo reproductivo
Get PDFThe distribution and abundance of the warty sea cucumber Parastichopus parvimensis in the islands Natividad (NI), Asunción (AI) and San Roque (SRI) on the western coast of Baja California Sur (BCS), Mexico, were examined based in independent data from commercial fishing in March and April 2009. The density was estimated from 345 sample units (SU = 10 m2 ) random selected between 2 and 30 m of depth. In NI, AI and SRI was found an average density and standard deviation (S) of 1.1 (1.02), 0.82 (1.06) and 0.83 (0.9) org/m2, and an average gutted weight of 158, 176, and 149g respectively. Changes in density were analyzed using a generalized linear model (GLM) with Gamma error structure, using the variables of depth and zone (islands) as well as the interaction effect, which was significant (p < 0.01). The analysis revealed a pattern of increasing density with the depth in SRI (p < 0.01) and non-significant in NI and AI. The variability of the density was high at all depths in NI (S = 10.2) and AI (S = 10.6), while SRI was only in >10 m depth (S = 9.0), but much less in water shallow (S = 2.7). The way in which the density varies on each island seems to be modulated by physical and biological characteristics related to the substrate, since 85% of the sampling units were associated with rocky substrate. We discuss possible factors that could influence the density changes with depth.Se estudió la distribución y abundancia del pepino de mar Parastichopus parvimensis, utilizando datos independientes de la pesca comercial en las islas Natividad (IN), Asunción (IA) y San Roque (ISR) de la costa occidental de Baja California Sur (BCS), México, en marzo y abril de 2009. La densidad se estimó a partir de 345 unidades de muestra de 10 m2 (UM) distribuidas al azar entre 2 y 30 m de profundidad. En IN, IA e ISR se encontró una densidad promedio y desviación estándar (S) de 1.1 (1.02), 0.82 (1.06) y 0.83 (0.9) org/m2 , y un peso eviscerado promedio de 158, 176, y 149 g respectivamente. Los cambios en densidad se analizaron con un Modelo Lineal Generalizado (MLG) con estructura de error Gamma, en función de las variables de profundidad y zona, así como del efecto de interacción entre ambas, el cual resultó significativo (p < 0.01). El análisis reveló un patrón de densidad creciente con la profundidad en ISR (p < 0.01) y no significativo en IN e IA. La variabilidad de la densidad fue alta en todas las profundidades en IN (S = 10.2) e IA (S = 10.6), mientras que en ISR solamente fue en más de 10 m de profundidad (S = 9.0), y mucho menor en aguas someras (S = 2.7). La forma en que varió la densidad en cada isla, parece estar modulada por características físicas y biológicas relacionadas al sustrato, ya que el 85% de las unidades de muestreo estuvieron asociadas a sustrato rocoso. Se discuten posibles factores que pueden influir en los cambios de la densidad con la profundidad