Ecología y estructura poblacional de los stocks reproductora-recluta, del camarón café Farfantepenaeus aztecus ives, 1891, en La Laguna Madre y plataforma continental de Tamaulipas, México

Se analiza la estructura demográfica, dinámica poblacional, variación temporal del camarón café Farfantepenaeus aztecus y su relación con factores ambientales en la Laguna Madre y Plataforma Continental de Tamaulipas, durante 1997. Además, se evalúa el volumen de la producción pesquera, durante el periodo 1987-2003, registrado por fuentes oficiales. Se revisaron un total de 31,982 camarones, de los cuales 23,495 (73.4%) son de la laguna y 8,487 (26.6%) marinos. Mayo y agosto son los meses mejor representados con 6,039 especimenes (25.7%) en la zona lagunar y 1,807 en altamar (21.2%), respectivamente. El 18% de los organismos, del total muestreado en cada stock, constituyen el pico modal de la longitud total, en los intervalos 80-84 mm de juveniles y 126-130 en adultos, con frecuencias intermensuales estadísticamente similares. Los juveniles presentaron picos máximos, de talla y peso, en los periodos julio-agosto y febrero-marzo, y los reproductores en mayo y septiembre. En la etapa juvenil, se encontraron diferencias significativas en la distribución espacial de las capturas y en la temporalidad de las tallas y pesos promedio. Se definieron dos períodos de alta y dos de baja abundancia para cada stock. La proporción sexual, en los juveniles, fue similar, con excepción de mayo, junio y octubre. El crecimiento es de tipo alométrico. El tiempo de permanencia del F. aztecus, en la laguna, es de aproximadamente 4.5 a 5.0 meses, donde alcanza tallas y pesos máximos promedio de 121.3 mm y 12.7 g en hembras y 108.7 mm y 10.91 g en machos; en alta mar, se estimó una media máxima, para sexos agrupados, de 218 mm y 68.9 g, a los 19 meses de edad. Los valores observados y esperados, en longitud y peso, son estadísticamente similares, en la estimación de los parámetros de crecimiento por stock, grupo y clases de edad y sexo. En los reclutas se estimó una cohorte principal y dos secundarias y en los adultos una condición multigeneracional. En el área lagunar, el número promedio mensual de especimenes, por biomasa, zona, cohorte y batimetría, es superior en los machos hasta en un 40%, 28.4%, 15% y 4%, respectivamente. La densidad promedio espacial y batimétrica, utilizando el mismo esfuerzo de pesca, fue mayor en la zona norte y en el área profunda, con 17.1% y 14.1%, correspondientemente. La producción de camarón en Tamaulipas, durante el periodo 1987-2003, fue de 190,419 toneladas (t), con un promedio anual de 11,201 t, donde el 42.3% correspondió a la captura lagunar y el 57.7% a la de altamar, alcanzando la mayor producción en 1995 y 1998 con más de 14,000 t/año. El volumen de producción, en la pesquería de lagunas, es 25.0% mayor en el primer semestre del año, donde el segundo trimestre representa el 54.5%; en altamar es 42.8% superior en el segundo semestre, y en el tercer trimestre constituye el 47.9%. Con el establecimiento de la veda, el volumen promedio, de la pesquería artesanal, se reduce en un 7.4%, mientras que la industrial se incrementa en 20.8%. La producción de camarón, en los cuerpos de agua lagunares, fue mayor en la época de estío y en la plataforma continental en la de lluvias. El sistema de corrientes y la presencia de canales de comunicación entre la laguna y el mar, así como el flujo migratorio de los reclutas a la pesquería, la época de reproducción y la explotación desmedida del recurso, fueron determinadas como las variables de mayor influencia en las variaciones mensuales, temporales e interanuales de la abundancia, tallas, proporción de sexos, edad y tasas de crecimiento, del F. aztecus. Abstract The demographic structure, population dynamics, temporary variation of brown shrimp Farfantepenaeus aztecus and their relation with environmental conditions from Laguna Madre and continental shelf of Tamaulipas in 1997 are analyzed. Furthermore, the volume of the fishing shrimp production according to official records, during the period 1978-2003, is evaluated. A total of 31,982 shrimps was checked out, of those 23,495 (73.4%) were captured in the lagoon and 8,487 (26.6%) in the marine region. May and August were the best represented months with 6,039 specimens (25.7%) found in the estuarine zone and 1,807 on the continental shelf (21.2%), respectively. The modal peak of total length, was at 80-84 mm for the juvenile stage and 126-130 mm for the adult, with inter monthly frequencies statistically similar. The juvenile presented maximum peak of size and weight, in July-August and February-March, and the adults in May and September. In the juvenile stage there were significant differences in the spatial distribution of the captures, and in the temporality of the average sizes and weight. Two periods were defined of high and two of low abundance for each stock. The sexual proportion in the juvenile ones was similar, except for May, June and October. The growth is considered allometric. The time of permanency of the F. aztecus in the lagoon is of approximately 4.5 to 5.0 months, in which period average sizes and weights reach 121.3 mm and 12.7 g in females and 108.7 mm and 10.91 g in males; in the marine region, average maxima of 218 mm y 68.9 g were estimated for males and females taken together, at the age of 19 months. The observed and expected length and weight values are statistically similar for the estimated parameters of growth, stock, age group and sex. One main and two secondary cohorts were identified in the recruits, while a multigenerational condition in the adults. In the lagoon area, the monthly average numbers of specimens, for biomass, area, cohort and depth, are superior in the males up to a 40%, 28.4%, 15% and 4%, respectively. The spatial and depth average density, using the same fishing effort, was greater in the northern area and in the deep area, with differences of 17.1% and 14.1%, respectively. The volume of the total production of shrimp in Tamaulipas, during the period 1987-2003, was of 190,419 metric tons (t) with an annual average of 11,201 t, 42.3% coming from the lagoon capture and 57.7% from the continental shelf, the greatest production being achieved in 1995 and 1998 with more than 14,000 t per year. The production volume in the fishery lagoons is 25% greater for the first semester of the year, where 54.5% correspond at the second trimester; while in the marine region it is 42.8% greater in the second semester, where about half for the over all capture occurs in the third trimester. After a closed season was settled, the inshore fishery average production diminished by 7.4%, while the offshore fishery increased 20.8%. The shrimp production was greater in summer time in the lagoon bodies, and during the rain season in the continental shelf. The currents system and the presence of communication channels between the lagoon and the sea, as well as the migratory flow of the recruits to the fishery, the reproduction term and the excessive exploitation of the resource, were determined as the variables than influenced the most in the monthly, temporary and inter annual variation of the abundance, sizes, proportion of sexes, age and growth rates of the F. aztecus

Updated checklist of estuarine caridean shrimps (Decapoda: Caridea) from the southern region of Laguna Madre, Tamaulipas, Mexico, with new records and a key for taxonomic identification

We provide an updated list of the caridean shrimp species from the southern region of the Laguna Madre, Tamaulipas, Mexico, along with a key for taxonomic identification. The survey was conducted in 3 sites during 3 temporal seasons. A total of 2,989 specimens were collected belonging to 12 species, 6 genera, and to the following 4 families: Alpheidae, Hippolytidae, Palaemonidae, and Processidae. Hippolytidae was the most abundant family, followed by Palaemonidae, Alpheidae, and Processidae. The hippolytid Hippolyte obliquimanus Dana, 1852, the palaemonids Palaemon floridanus Chace, 1942, and P. northropi (Rankin, 1898), and the alpheid Alpheus cf. packardii Kingsley, 1880 represent new records for the Laguna Madre and selected areas of the Gulf of Mexico.&nbsp

Size, Age, and Spatial-Temporal Distribution of Shortfin Mako in the Mexican Pacific Ocean

Abstract Basic population parameters such as age, size, and distribution have been poorly evaluated for the Shortfin Mako Isurus oxyrinchus in the Mexican Pacific Ocean. According to data collected by scientific observers on board medium-size fishing vessels during the period of 2006–2013, size as TL was obtained for 5,740 individual sharks. The range of TL was 70–362 cm for females and 71–296 cm for males. Weight (W), measured randomly from 1,409 individuals, ranged from 2 to 90 kg for females and from 2 to 80 kg for males. The weight-to-TL ratio was best fitted by the equation W = 4 × 10−5(TL)2.59 (r2 = 0.6532). No sex-specific difference was found in the weight-to-TL relationship between males and females, nor in W or TL separately. By using the inverse von Bertalanffy equation and parameters described by other authors for the same study area, we determined the age range for individuals captured on the basis of their TL. The age ranged from 0 to 39 years in females and from 0 to 21 years in males. Using a logistic model, the mean length at sexual maturity was obtained for 2,532 males (TL = 190 cm). The quarterly distribution of young of the year and 1-year-old juveniles showed that there is a tendency for these sharks to mov

Freshwater fishes and water status in Mexico: A country-wide appraisal.

Mexico is the southernmost country in North America, and extends into Central America, south of the Isthmus of Tehuantepec. The northern half of M´exico is located on the Temperate belt and is arid in character (Nearctic), while the rest is within the Tropical belt (Neotropical). Climate varies from extremely temperate desert in the north, to tropical humid in the south.M´exico has more than 500 freshwater fish species, about 271 of them country endemics, and approximately 48 endemics from binational basins. There are still some 30–40 fish species not yet described. There are 563 fish species colonizing coastal flood plain species. In addition to the numbers of colonizing fishes, the burden of introduced exotics has also been growing. In 1904, only 4 species were recognized as exotics; by 1997 the number had increased to 94, and by 2008 to 11

Tamaño y densidad de Neaxius vivesi (Thalassinoidea: Axüdae), en Bahía de Los Angeles, Baja California, México

Digging shrimp Neaxius vivesi (Bouvier 1895) were eollected with harpoon in February, May and August of 1986 in Bahía de Los Angeles, B.C., Mexico (28"53' N; 113"34' W). Burrows were randomly sampled with a Ix l m quadral. 39 speeiemens were captured, 19 in February, 12 in May and 8 in August;. 54% were female, but males were better represented in February and August. Length and weight means were 91.6 mm and 14.6 g. February females and May gmales had the highest means, and maximun individual values were registered for females in February and minimum for females in August. The weight-size, Icorrelation (both sexes) was of r > 0.80 (t > 0.05). A clear alometry was observed .. Density highestcouldreach an average of 9 burrows 1m2. Each burrow had one male and one female, wmch alternated in feeding.Digging shrimp Neaxius vivesi (Bouvier 1895) were eollected with harpoon in February, May and August of 1986 in Bahía de Los Angeles, B.C., Mexico (28"53' N; 113"34' W). Burrows were randomly sampled with a Ix l m quadral. 39 speeiemens were captured, 19 in February, 12 in May and 8 in August;. 54% were female, but males were better represented in February and August. Length and weight means were 91.6 mm and 14.6 g. February females and May gmales had the highest means, and maximun individual values were registered for females in February and minimum for females in August. The weight-size, Icorrelation (both sexes) was of r > 0.80 (t > 0.05). A clear alometry was observed .. Density highestcouldreach an average of 9 burrows 1m2. Each burrow had one male and one female, wmch alternated in feeding

Biología y ecología del camarón del fango común Upogebia dawsoni (Crustacea: Thalassinoidea) del Manglar Requesón, Bahía Concepción y el Estero Río Mulege, Baja California Sur, México.

Some aspects on the biology of the mud shrimp. Upogebia dawsoni from the Requeson mangrove area, whithin Bahia Concepcion, and Mulege river estuary, Mulege (Baja California Sur, México) are described. Collections of U. dawsoni were done in January (winter), March (Spring) and July (Summer) in 1986 at Requeson, and in October (Fall) of 1985 and June (summer) of 1986, at Mulege. A total of 280 individuals were collected between 0.40 and 1.0 m in depth. Size, sex ratio, spawning period, egg number, stomach contents and external morphology were recorded. A seasonal comparative analysis between the two localities showed that the specimens from Requeson had greater lengths. In Summer, females represented 6.67% and juveniles 93.33% while in Fall, females represented 93.27%, males 3.58%, juveniles 2.25%, and ovigerous females, stage II 0.90% at Mulege. In Winter, females comprised 30.76%, at Requeson. Two spawning periods were detected, one in Fall (Mulege), and other in Summer (Requeson). The largest female (total length= 28.0 mm) carried out 2133 eggs and the shortest one (total length = 11.0 mm) had 119 eggs. Sediment, leaves and roots of mangrove, insect wings, diatoms, dinoflagellates bacteria, and sponge spicules were found in the stomachs. Se estudia el camarón del fango común Upogeliua dawsoni, del Manglar Requesón, Bahía Concepción y el Estero Mulugé, Mulugé, Baja California Sur. Colectamos U. dawsoni en Requesón en enero (invierno), marzo (primavera) y junio (verano) de 1986 y en Mulugé en octubre (otoño) de 1985, así como en junio (verano) de 1986. Obtuvimos un total de 280 ejemplares entre los 0.40 y 1.0m de profundidad. Realizamos mediciones de tallas, proporción de sexos, período de desove, recuento de huevos, estudio de contenido estomacal y caracterización de su morfología externa. Se hizo un análisis comparativo estacional entre las dos localidades y se encontró que las tallas de los especímenes siempre fueron mayores en el Requesón que en Mulugé. En proporción de sexos para Mulugé en el verano las hembras representaron 6.67% y los juveniles 93.33%; para el otoño las hembras constituyeron el 93.27%, los machos 3.58%, los juveniles 2.25% y las hembras ovígeras en estado II el 0.90%. Para Requesón en el invierno las hembras formaron el 90.90% y los machos el 9.09% en primavera las hembras representaron 61.11% y los machos 38.88%; el verano es dominado por hembras ovígeras en estados I y II. Siendo 55.85% para el I y 15.38% para el II, más el 30.76% formado por machos. Se presentaron dos períodos de desove, uno en el otoño (Mulegé) y otro en el verano (Requesón). Para el recuento de huevos se analizaron 11 hembras ovígeras, la más grande (longitud total = 28.0 mm) tenía 2133 huevos y la más pequeña (longitud total = 11.0 mm) portaba 119 huevos. En el análisis de contenido estomacal se encontró sedimento, trozos de hojas y raíces de mangle, alas de insectos, diatomeas, dinoflagelados, bacterias y espículas de esponjas.

Composición y estructura de las comunidades de poliquetos (Annelida) asociadas a fondos blandos de la costa occidental de la península de Baja California, México

ResumenLos poliquetos son uno de los grupos más importantes en el bentos desde cualquier punto de vista. Con el presente estudio se tiene el propósito de caracterizar la riqueza específica de la fauna de poliquetos de la costa occidental de Baja California, desde la boca de bahía Magdalena hasta punta Colonet, a través de recolectas realizadas por el crucero oceanográfico SIMSUP VIII. Se comparó latitudinal y batimétricamente el número de familias y especies encontradas en el estudio; asimismo, se realizó un análisis ecológico utilizando los índices de diversidad alfa, diversidad de Shannon-Wiener, dominancia de Simpson y equitatividad de Pielou. Se revisó un total de 60estaciones; 30 de estas fueron positivas, las cuales resultaron en 3,709organismos agrupados en 11órdenes, 27familias, 62géneros y 99especies. La familia Spionidae presenta la mayor riqueza con 4géneros y 12especies (12.2% de la diversidad global y 42.7% de la abundancia relativa) para un total de 1,583 ejemplares. Paraprionospio pinnata fue la especie más abundante, frecuente y dominante (24.2% del total de ejemplares). Del total de muestras, el 53.8% pertenecen a la zona centro, 26.9% a la sur y 19.2% a la norte. Se encontró la mayor riqueza (85.9%) y abundancia (62.8%) en la zona centro.AbstractPolychaetes are one of the most important groups of the benthos from any point of view. The present study aims to characterize the species richness of polychaete fauna of the West Coast of Baja California, from the mouth of Magdalena Bay to Punta Colonet. Collections were made by the Oceanographic Cruise SIMSUP VIII. We compared the number of families and species collected both bathymetricaly and latitudinally, we also performed a diversity analysis using several indexes such as alpha diversity, Pielou evenness, Simpson dominance and specific dominance. A total of 60stations were revised, 30 of these were positive, finding 3,709specimens grouped in 11orders, 27families, 62genera and 99species. Spionidae has the highest richness with 4genera and 12species (12.2% of global diversity and 42.7% of the relative abundance) for a total of 1,583 specimens. Paraprionospio pinnata was the most abundant, frequent and dominant species (24.2% of all specimens). Of the total sample, 53.8% belong to the central zone, 26.9% to the southern one and 19.2% to the northern one. The highest richness (85.9%) and abundance (62.8%) correspond to the central zone