The role of spine length in crustacean and fish associations with echinoids at Los Cabos, Baja California Sur, Mexico / El papel de la longitud de la espina en la asociación de crustáceos y peces con equinoideos en Los Cabos, Baja California Sur, México

Introduction: Echinoids (sea urchins) provide shelter for a variety of facultative or obligatory ectosymbionts. Objective: To evaluate the hypothesis that decapods and fishes prefer to associate with echinoid individuals and species that have longer spines. Methods: We visually studied the frequency of decapod crustaceans and fishes associated with echinoids in shallow water (< 4 m) and deeper water (5-20 m) at Los Cabos, Baja California Sur, Mexico, during 1-6 January 2019. Results: We inspected 1 058 echinoids of six species. Five decapod species associated with three species of echinoids. When compared with other echinoid species, in shallow water, decapods associated 5.1 times more often with the longest-spined echinoid Diadema mexicanum (7.0 times more decapods per individual D. mexicanum); in deeper water, association frequency was similar for all echinoid species. Fourteen fish species associated with four echinoid species. In shallow water, fishes associated 2.6 times more with D. mexicanum (4.5 times more fishes per individual). There was no preferred echinoid species in deeper water. Longer-spined D. mexicanum had more decapods and fishes. Associations were more frequent in shallow water. Multiple individuals and species of decapods and fish often associated together with a single D. mexicanum. The decapod that presumably is Tuleariocaris holthuisi showed a possible obligatory association with one of the equinoids (D. mexicanum); the other decapods and all fish species are facultative associates. Conclusion: Our results support the hypothesis that decapods and fishes associate most frequently with echinoids with the longest spines, presumably to reduce the risk of predation.

Introducción: Los equinoideos (erizos de mar) brindan refugio a una variedad de ectosimbiontes facultativos u obligatorios. Objetivo: Evaluar la hipótesis de que los decápodos y los peces prefieren asociarse con individuos y especies de equinoideos con espinas más largas. Métodos: Estudiamos visualmente la frecuencia de crustáceos decápodos y peces asociados con equinoideos en aguas poco profundas (< 4 m) y aguas más profundas (5-20 m) en Los Cabos, Baja California Sur, México, del 1-6 de enero 2019. Resultados: Examinamos 1 058 equinoideos de seis especies. Cinco especies de decápodos se asociaron con tres especies de equinoideos. Al comparar con otras especies de equinoideos, en aguas poco profundas, los decápodos se asociaron 5.1 veces más frecuentemente con la especie de equinoideo de espinas más largas, Diadema mexicanum (7.0 veces más decápodos por individuo en D. mexicanum); en aguas más profundas, la frecuencia fue similar para todas las especies de equinoideos. Catorce especies de peces se asociaron con 4 especies de equinoideos. En aguas poco profundas, los peces se asociaron 2.6 veces más con D. mexicanum (4.5 veces más peces por individuo). No hubo preferencia por una especie de equinoideo en aguas más profundas. Individuos de D. mexicanum con espinas largas tuvieron más asociación con decápodos y peces. Las asociaciones se dieron con mayor frecuencia en aguas poco profundas. Múltiples individuos y especies de decápodos y peces a menudo se asociaron con un solo D. mexicanum. Un decápodo que presumiblemente es Tuleariocaris holthuisi mostró una posible asociación obligatoria con uno de los equinoideos (D. mexicanum); las otras especies de decápodos y todas las especies de peces presentaron asociaciones facultativas. Conclusión: Nuestros resultados apoyan la hipótesis de que los decápodos y los peces se asociaron con mayor frecuencia con los equinoideos con las espinas más largas, presumiblemente para reducir el riesgo de depredación.

Áreas en riesgo de invasión por Procambarus clarkii (Decapoda: Cambaridae) un cangrejo de río introducido en Colombia / Areas at risk of invasion by Procambarus clarkii (Decapoda: Cambaridae) a crayfish introduced in Colombia

Introducción: El proceso de invasión biológica es una de las mayores amenazas a la biodiversidad y ecosistemas, con actuales y potenciales impactos en la salud pública y conservación. Procambarus clarkii es un crustáceo decápodo, originario del sur de Estados Unidos y noreste de México, que puede adaptarse a diferentes condiciones ambientales debido a su plasticidad ecológica. Objetivo: Se caracterizó el nicho ecológico fundamental existente de Procambarus clarkii con el fin de predecir las áreas con idoneidad ambiental para el potencial establecimiento de la especie en Suramérica y Colombia. Métodos: Usamos modelos de nichos ecológicos calibrados en el área nativa, elaborados con el algoritmo Maxent, basados en datos de presencia extraídos de GBIF y variables hidroclimáticas de ecosistemas acuáticos a una resolución de 1 km2. Resultados: En Suramérica el modelo indicó un potencial geográfico amplio de invasión mostrando áreas ambientalmente idóneas para la presencia y expansión hacia Colombia, Venezuela, Perú, Ecuador, Brasil, Guyana, Surinam, Bolivia, Uruguay, Argentina, Paraguay y Chile. En Colombia, el modelo predijo que las áreas idóneas se ubican principalmente en el norte y oriente, incluidos diversos ecosistemas, como: bosques tropicales, bosques basales, bosques riparios y sabanas. La especie tiene una alta posibilidad de expandirse hacia áreas de distribución de latitudes bajas, ocupando zonas hacia la parte norte de la región Caribe colombiana, en departamentos de Magdalena, Cesar, Córdoba y Atlántico. También se predijo áreas con idoneidad ambiental en el oriente de Colombia, hacia la extensión de la planicie oriental de la Orinoquia, una región de baja altitud en: Arauca, Casanare, Meta y Vichada. Conclusión: En este estudio se aplican modelos de nichos ecológicos, que puede ser de interés en la planeación de estrategias o la creación de planes de manejo, como sistemas de alerta temprana para evitar el establecimiento de esta especie.

Introduction: Biological invasions are a major threat to biodiversity and ecosystems, with current and potential impacts on public health and conservation. Procambarus clarkii is a decapod crustacean, native to the Southern United States and Northeastern Mexico, which may adapt to different environmental conditions due to its ecological plasticity. Objective: The existing fundamental ecological niche of Procambarus clarkii was characterized in order to predict areas with environmental suitability for the potential establishment of the species in South America and Colombia. Methods: We used models of calibrated ecological niches in the native area, elaborated with the Maxent algorithm, based on occurrence data extracted from GBIF and hydroclimatic variables of aquatic ecosystems at a resolution of 1 km2. Results: The model indicated a wide geographic area for invasion potential in South America, predicting environmentally suitable areas for the presence and expansion towards Colombia, Venezuela, Peru, Ecuador, Brazil, Guyana, Surinam, Bolivia, Uruguay, Argentina, Paraguay and Chile. In Colombia, suitable areas predicted by the model are located mainly in the North and East of the country, spanning a diversity of ecosystems, such as tropical forests, basal forests, riparian forests and savannas. The species has a high possibility of expanding into low latitude distribution areas, occupying areas towards the Northern part of the Colombian Caribbean region, in the departments of Magdalena, Cesar, Cordoba and Atlántico. Suitability areas environmental were also predicted in Eastern Colombia, towards the extension of the Eastern plain of the Orinoquia, a low altitude region in Arauca, Casanare, Meta and Vichada. Conclusion: This study applies ecological niche models, which may be of interest in the planning of strategies or the creation of management plans, such as early warning systems that prevent the establishment of this species.

Influencia de la proporción sexual y del ambiente en la tasa de crecimiento poblacional de Callinectes bellicosus (Decapoda: Portunidae) del Golfo de California / Sex ratio and environmental influence on population growth rate of Callinectes bellicosus (Decapoda: Portunidae) in the Gulf of California

ResumenPara la jaiba café (Callinectes bellicosus) capturada en Sonora, México dentro del Golfo de California desde 1986, durante 20 años se ha observado una tendencia decreciente en la biomasa. Se estimaron las tasas de crecimiento poblacional (r) y proporción de sexos de C. bellicosus además de tres parámetros que describen su hábitat: temperatura del mar, extensión de humedales y tamaño del hábitat en cuatro zonas a lo largo de la costa de Sonora. La proporción de sexos se estimó de 25 556 jaibas muestreadas de las capturas comerciales en los años 19982002 y 2012; la temperatura media en el período de desove (mayo-agosto) se generó a partir de sensores remotos en los mismos años; la cobertura de humedales se obtuvo de reportes publicados; y el tamaño del hábitat se estimó como la superficie de pesca. Para cada zona se estimó r mediante un método desarrollado para situaciones de escasa información utilizando las capturas comerciales (t) de 1986 a 2013. Con los datos de las cuatro zonas se desarrollaron modelos de regresión lineal simple y múltiple para evaluar las sensibilidades teóricas de r a variaciones en la proporción de sexos y en los parámetros ambientales. Los machos dominaron (68.8 %) sobre las hembras en el período de estudio en las cuatro zonas; un análisis de conglomerados identificó dos grupos de acuerdo a la proporción de sexos: un grupo norteño con las zonas 1 y 2, y otro sureño con las zonas 3 y 4. Los valores de r fueron diferentes en las cuatro zonas (P<0.001) igual que la proporción de sexos (P=0.037); no se encontraron diferencias en la temperatura entre los años considerados en el estudio (P>0.995). Tanto los datos estimados como los análisis de sensibilidad sugieren que r dependen directa y positivamente de la proporción de hembras de jaiba y el tamaño de los humedales. Por lo anterior planteamos la hipótesis de que la pesca excesiva de hembras es la causa del descenso de la biomasa de jaiba café en Sonora, y concluimos que es conveniente implementar refugios pesqueros dentro de humedales costeros para proteger las hembras en el período de desove.

Abstract:The brown swimming crab (Callinectesbellicosus) is an economically important species in the Gulf of California, and its fishing activity, held in Sonora from 1986, has been affected by a 20-year declining trend in its biomass. With the aim to understand the possible reasons of this species population changes along time, we estimated population growth rate (r) and sex ratio of C. bellicosus, and combined them with three parameters describing its habitat: sea temperature, wetland extension and habitat size in four areas along the coast of Sonora. For this, monthly mean sex ratio was estimated from crabs samples obtained from commercial catches during 1998-2002 and 2012; mean sea surface temperature for the spawning period (May-August) were derived from remote sensors for the same years; while wetland coverages were obtained from published reports, and habitat size was estimated as the fishing surface. For each area, r was estimated using a method developed for limited data situations using commercial landings (t) from 1986-2013. With data from the four areas, simple and multiple linear regression models were developed to ascertain theoretical sensitivities of r to variations in sex ratio and environmental parameters. A total of 24 556 crabs were sampled; males dominated (68.8 %) over females during the study period and in all areas; a cluster analysis identified two groups according to sex ratio: a Northern group with zones 1 and 2, and a Southern group with zones 3 and 4. r values were different in all zones (P<0.001) as was sex ratio (P=0.037); no differences in temperature were identified within the study years (P>0.995). Both the estimated data and sensitivity analyses suggest the existence of a direct and positive dependence of r on the proportion of female crabs and wetland size. We hypothesize that excess fishing of females caused the declining biomass trend of the brown swimming crab in Sonora, and concluded on the convenience of implementing harvest refugia inside coastal wetlands to protect females during the spawning season. Rev. Biol. Trop. 64 (3): 1259-1271. Epub 2016 September 01.

Evaluación del crecimiento de Callinectes sapidus (Decapoda: Portunidae) con métodos basados en talla, Tamaulipas, México / Evaluation of the growth of Callinectes sapidus (Decapoda: Portunidae) by the use of lengthbased methods based on size in Tamaulipas, Mexico

ResumenLa captura de la jaiba azul (Callinectes sapidus) es una de las principales del Estado de Tamaulipas, México, tanto por su volumen y precio de venta, como por la generación de empleo, pero se cuenta con escasa información de sus características biológicas. El objetivo del presente estudio fue evaluar los parámetros de crecimiento de la jaiba azul, estableciendo el método más adecuado para realizarlo. Se estimó la frecuencia de tallas de 17 814 jaibas de muestreos realizados de enero a junio 2009, provenientes de la captura comercial de trece localidades, comprendidas en cuatro lagunas costeras: Laguna El Barril, Laguna Madre, Laguna de Morales y Laguna de San Andrés. Los parámetros de crecimiento se estimaron usando los métodos indirectos ELEFAN, PROJMAT y SLCA en combinación con la técnica jackknife para establecer la incertidumbre de las estimaciones inherentes a cada método. Los parámetros de crecimiento L∞ y k se unificaron para efectos comparativos mediante el índice de crecimiento phi prima (Φ’). Con una moda de 110 mm, el intervalo de longitud de caparazón varió entre 60 y 205 mm. Los valores de los parámetros de crecimiento variaron de acuerdo al método utilizado. Utilizando SLCA, L∞ varió entre 259 y 260 mm y k osciló entre 0.749 y 0.750/año; con PROJMAT, L∞ registró valores entre 205 y 260 mm y k fluctuó entre 0.550 y 0.740/año, y con ELEFAN, L∞ osciló entre 156 y 215 mm y k varió entre 0.479 y 0.848/año. Las estimaciones mediante jackknife detectaron nula variabilidad en Φ’ entre localidades y diferencias significativas entre métodos. Los rangos de valores de Φ’ estimados por SLCA y PROJMAT (4.70 a 4.71 y 4.66 a 4.70, respectivamente) se ubicaron en el rango reportado por la literatura (4.201-4.798), mientras que ELEFAN aportó valores significativamente menores (3.87 a 4.27). Los métodos SLCA y PROJMAT en combinación con la técnica jackknife, resultaron ser los más adecuados para estimar los parámetros de crecimiento de C. sapidus.

AbstractThe capture blue crab (Callinectes sapidus) is one of the major fisheries of the state of Tamaulipas, Mexico; both in volume and selling price, as well as employment generation, but there is little information on its biological characteristics. The aim of this study was to evaluate the growth parameters of the blue crab, establishing the most appropriate method. We estimated the length frequency of 17 814 crabs from commercial catch of thirteen locations, including four coastal lagoons. The lagoons were El Barril, Madre, Morales and San Andrés from Tamaulipas, State. Growth parameters were evaluated using indirect methods ELEFAN, PROJMAT and SLCA in combination with the jackknife technique to establish the uncertainty of estimates inherent in each method. The growth parameters L∞ and k were consolidated for purposes of comparison with the growth index phi prime (Φ’). With a mode of 110 mm, the interval carapace length varied between 60 and 205 mm. The values of the growth parameters varied according to the method used. Using SLCA, L∞ varied between 259 and 260 mm and k ranged between 0.749 and 0.750 /year; with PROJMAT, L∞ recorded values between 205 and 260 mm, k fluctuated between 0.550 and 0.740/year, and with ELEFAN, L∞ ranged between 156 and 215 mm and k varied between 0.479 and 0.848/year. Estimates by jackknife detected no variability in Φ’ between locations and significant differences between methods. The ranges of values of Φ’ and PROJMAT estimated SLCA (4.70 to 4.71 and 4.66 to 4.70, respectively) were in the range reported in the literature (4.201-4.798), while lower values ELEFAN contributed significantly (3.87 to 4.27). The SLCA and PROJMAT methods in combination with the jackknife technique, proved to be the most suitable to estimate the growth parameters of C. sapidus. Rev. Biol. Trop. 64 (2): 821-836. Epub 2016 June 01.

Suscetibilidade dos estágios ontogenéticos: padrão osmorregulatório em camarões peneídeos e palemonídeos / Susceptibility of ontogenetic stages: osmoregulatory standard in penaeid and palaemonid shrimps / Susceptibilidad de etapas ontogenéticas: estándar osmorregulatorio en camarones peneídeos y palemonídeos

A invasão da água doce por crustáceos ocorreu repetidamente ao longo dos anos, pressionando um ajuste em seus processos fisiológicos. A habilidade de sobreviver aos diferentes ambientes foi encontrada em traços osmorregulatórios, e estão relacionadas à capacidade de regular o fluido extracelular. Portanto, o objetivo deste manuscrito é explorar os processos osmorregulatórios de camarões palemonídeos e peneídeos, visualizando um padrão na capacidade osmorregulatória em ambas as famílias e, em particular, tratar de assuntos pertinentes aos efeito no ciclo ontogenético e o efeito ocasionado pelo nitrito na hemolinfa de crustáceos. Comparando palemonídeos e peneídeos, percebe-se que o sucesso da conquista do ambiente dulcícola, e a não necessidade de hiporregulação, levou à perda dessa capacidade na maioria dos palemonídeos. Dessa forma, se supõem um ancestral com capacidade hiporregulatória, uma vez que invertebrados marinhos são, parcimoniosamente, osmoconformadores. Compara-se também que o nitrito apresenta efeito nas proteínas presentes na hemolinfa dos crustáceos quando submetidos à exposição natural ou induzida deste composto, e que a capacidade osmorregulatória é, portanto, variada de acordo com seus estágios...

The invasion of freshwater by crustaceans has occurred repeatedly over the years, pressing for an adjustment in their physiological processes. The ability to survive in different environments was found in osmoregulatory traits and is related to the ability to regulate the extracellular fluid. Therefore, the purpose of this manuscript is to explore the osmoregulatory processes in palaemonid and penaeid shrimps, which display a pattern of osmoregulatory capacity in both families and, in particular, to deal with matters related to the effects on ontogenetic cycle and the effect raised by nitrite in crustacean hemolymph. By comparing palaemonid and peneid shrimps, it is possible to note the success of conquering freshwater environment, and not the need for hypo-regulation, has led to the loss of this capability in most palaemonids. Thus, it is assumed that they share an ancestor with hypo-regulatory capacity, since marine invertebrates are sparsely osmoconformers. The article also compares that nitrite has effect on proteins present in the hemolymph of crustaceans when subjected to natural or induced exposure to these compound, and osmoregulatory capacity is therefore varied according to their stages...

La invasión del agua dulce por crustáceos ocurre repetidamente a lo largo de los años, pulsando un ajuste en sus procesos fisiológicos. La capacidad de sobrevivir en diferentes ambientes se ha encontrado en rasgos osmorregulatorios y están relacionados a la capacidad de regular el fluido extracelular. Por lo tanto, el objetivo de este manuscrito es el de explotar los procesos osmorregulatorios de camarones palemonídeos y peneídeos, se muestra un estándar en la capacidad osmorregulatoria en ambas las familias y, en especial, trata de cuestiones relativas a los efectos sobre los ciclo ontogenético y el efecto causado por nitrito en la hemolinfa de crustáceos. Comparando palemonídeos y peneídeos, se da cuenta de que el éxito de la conquista del ambiente dulcícola, y sin necesidad de hipo regulación, condujo a la pérdida de esa capacidad en la mayoría de los palemonídeos. Así, se supone un ancestral con capacidad hipo regulatoria, una vez que los invertebrados marinos son, parsimoniosamente, osmoconformadores. Se compara también que el nitrito presenta efectos en las proteínas presentes en la hemolinfa de los crustáceos cuando sometidos a la exposición natural o inducida por estes compuesto, y que la capacidad osmorregulatoria es, por lo tanto, variada de acuerdo con sus etapas...

Population biology of the mangrove crab Ucides cordatus (Decapoda: Ucididae) in an estuary from semiarid Northeastern Brazil / Biología poblacional del cangrejo de manglar Ucides cordatus (Decapoda: Ucididae) en un estuario tropical semiárido

The mangrove crab Ucides cordatus is an important resource of estuarine regions along the Brazilian coast. U. cordatus is distributed from Florida, USA, to the coast of Santa Catarina, Brazil. The species plays an important role in processing leaf litter in the mangroves, which optimizes the processes of energy transfer and nutrient cycling, and is considered a keystone species in the ecosystem. Population declines have been reported in different parts of the Brazilian coast. In the present study we evaluated aspects of the population structure, sex ratio and size at morphological sexual maturity. We analyzed 977 specimens collected monthly over 24 months (2010-2012), in a mangrove of the Jaguaribe River, in the municipality of Aracati on the East coast of Ceará state, Northeastern Brazil. The study area has a mild semiarid tropical climate, with mean temperatures between 26 and 28oC. The area is located within the eco-region of the semiarid Northeast coast, where mangroves occur in small areas and estuaries are affected by mesomareal regimes. The population structure was evaluated by the frequency distribution of size classes in each month, and the overall sex ratio was analyzed using the chi-square test. Size at morphological sexual maturity was estimated based on the allometry of the cheliped of the males and the abdomen width of the females, using the program REGRANS. The size-frequency distribution was unimodal in both sexes. The overall sex ratio (M: F) (1:0.6) was significantly different from 1:1. Analysis of the sex ratio by size class showed that the proportion of males increased significantly from size class 55-60mm upward, and this pattern persisted in the larger size classes. In the smaller size classes the sex ratio did not differ from 1:1. The size at morphological sexual maturity was estimated at a carapace width (CW) of 52mm and 45mm for males and females, respectively. Analysis of the population parameters indicated that ...

El cangrejo Ucides cordatus es un importante recurso pesquero de las regiones de estuarios a lo largo de la costa brasileña. Disminuciones de las poblaciones han sido reportadas en diferentes regiones del país. El presente estudio evaluó aspectos de la estructura poblacional, proporción sexual y talla en la madurez sexual. Se analizó un total de 977 ejemplares capturados mensualmente, por 24 meses, en lo manglar del río Jaguaribe, en el municipio de Aracati, en la costa este de Ceará, nordeste del Brasil. El área de estudio tiene un clima semiárido tropical, con temperaturas medias entre los 26 y 28°C. La estructura poblacional fue evaluada para determinar la distribución de frecuencia de clases de talla. Para analizar diferencias significativas respecto a la proporción sexual se aplicó la prueba Chi-quadrado. La talla de la madurez sexual morfológica fue estimada con base en la alometría del propodito del quelípedo de los machos y de la anchura del abdomen de las hembras, utilizando el programa REGRANS. La distribución de frecuencia de talla fue unimodal para los dos sexos. La proporción sexual total (M:H)(1:0.6), se desvió significativamente de la igualdad. El análisis de la proporción entre sexos, relativo a las clases de tallas mostró que la proporción de machos se tornó significativamente más alta desde la clase de 55-60mm de talla, y este se mantuvo en las clases de talla más grande. No obstante, en las clases más pequeñas la proporción entre los sexos no fue distinta de 1:1. La talla de la madurez sexual morfológica fue de 52mm de ancho del caparazón y 45mm para los machos y hembras, respectivamente. Los resultados de los atributos analizados permitieran deducir que la población de U. cordatus en el manglar del río Jaguaribe se encuentran en una situación de estabilidad. Sin embargo, el monitoreo constante de la población es necesario para detectar alteraciones en los atributos de la población que puedan afectar esta situación de estabilidad.

Artificial family selection based on growth rate in cultivated lines of Litopenaeus vannamei (Decapoda, Penaeidae) from Venezuela

We investigated the effects of family selection on the growth rates of four genetic lines of Litopenaeus vannamei, the Pacific white shrimp, from Venezuela. The mean family weight at selection was 16.79 g and the mean growth rate was 0.169 g d-1 at a mean age of 138 days. The mean growth rates per generation were 0.141 g d-1 for the parental generation (P0), 0.173 g d-1 for the F1 and 0.191 g d-1 for the F2. Survival varied from 83.3 percent to 94.4%. There were statistically significant differences between lines, with lines B and C, growing at higher temperatures and lower salinities, showing the fastest growth. Regression analysis between growth rate and age for each genetic line showed high r² values, but smaller than those shown between growth rate and generation. The mean heritability (h²) estimated for growth rate was 0.25 ± 0.04, with line per generation values ranging from 0.18 to 0.38. The mean heritability for growth rate per line showed some variation but there was no correlation between heritability and growth rate. Females showed a greater gain in growth rate per generation than males due to their faster growth when they were older. This study shows the high potential of these L. vannamei populations for the future of shrimp culture in the Americas.

Lecithotrophic behaviour in zoea and megalopa larvae of the ghost shrimp Lepidophthalmus siriboia Felder and Rodrigues, 1993 (Decapoda: Callianassidae)

Food supply is considered critical for a successful culturing of decapod larvae. However, some species may present yolk reserve sufficient to complete their larval development without external food supply (known as lecithotrophic larval development). In the present study, two experiments were carried out in order to verify whether the callianassid Lepidophthalmus siriboia have lecithotrophic behaviour or, if they need external food for their larval development: Experiment 1, larvae submitted to an initial feeding period and Experiment 2, larvae submitted to an initial starvation period. High survival rate was observed in both experiments, in which only 2 megalopae and 1 zoea III died. These results strongly suggest that larvae of L. siriboia are lecithotrophic as they have sufficiently large yolk reserve to complete their larval development, while the megalopa stage shows facultative lecithotrophy. The larval periods of each stage of the treatments were quite similar and, despite some significant differences in some larval periods, these can be related probably to larval rearing conditions, abiotic factors or, individual variability of larval health, as well as stress caused to the ovigerous females during embryogenesis.

A alimentação é considerada crítica em cultivo de larvas de decápodes. No entanto, algumas espécies podem apresentar reservas nutritivas suficientes para completar o desenvolvimento larval sem a necessidade de alimentação externa (conhecido como desenvolvimento larval lecitotrófico). No presente estudo, dois experimentos foram realizados para verificar se o callianassídeo Lepidophthalmus siriboia tem comportamento lecitotrófico ou se precisa de alimento externo para completar o desenvolvimento larval: Experimento 1, larvas submetidas a um período inicial de alimentação e, Experimento 2, larvas submetidas a um período inicial de inanição. Em ambos os experimentos, observou-se altas taxas de sobrevivência, com apenas 2 megalopas e 1 zoea III mortos. Estes resultados sugerem fortemente que larvas de L. siriboia são lecitotróficas, tendo reservas suficientes para completar o desenvolvimento larval, enquanto o estágio de megalopa apresenta lecitotrofia facultativa. Os períodos larvais de cada estágio nos tratamentos foram bastante semelhantes. No entanto, foram observadas algumas diferenças significantes entre alguns períodos, os quais podem estar relacionados às condições de cultivo, provavelmente devido a fatores abióticos, à variabilidade individual da condição larval, ou ainda a fatores como estresse causado às fêmeas ovígeras durante embriogênese.

The importance of feeding in the larval development of the ghost shrimp Callichirus major (Decapoda: Callianassidae)

The present study investigated whether the callianassid Callichirus major shows a lecithotrophic behaviour during larval development. Two experiments were carried out. In the first experiment, larvae were subjected to an initial period of feeding, while in the second they were subjected to an initial period of starvation. In Experiment 1, 80 percent of C. major larvae succeeded moulting to juvenile stage in treatment with larvae fed every day. In the treatments with larvae fed for 1, 2 and 3 days there was total mortality before they reached the megalopal stage. In Experiment 2, zoea larvae showed more resistance when subjected to an initial period of starvation in which larvae starved for 1, 2 and 3 days and had survival rates of 100, 60 and 80 percent, respectively. But, a delay in the development duration of the zoeal stages was observed. Total mortality was observed for larvae reared in the treatment with entire starvation. The results suggest that zoeal stages of C. major are not lecithotrophic.

O presente estudo investigou se o callianassid Callichirus major apresenta um comportamento lecitotrófico durante o desenvolvimento larval. Dois experimentos foram realizados. No primeiro experimento, larvas foram submetidas a um período inicial de alimentação, enquanto no segundo elas foram submetidas a um período inicial de inanição. No experimento 1, 80 por cento das larvas de C. major mudaram com sucesso para o estágio de juvenil no tratamento com larvas alimentadas diariamente. Nos tratamentos com larvas alimentadas por 1, 2 e 3 dias, houve uma mortalidade total antes de alcançarem o estágio de megalopa. No experimento 2, as larvas zoés mostraram mais resistência quando submetidas a um período inicial de inanição. Nos tratamentos nos quais as larvas estiveram em inanição por 1, 2 e 3 dias, as taxas de sobrevivência foram100 por cento, 60 por cento e 90 por cento, respectivamente. Porém atrasos na duração do desenvolvimento dos estágios de zoés foram observados. Houve mortalidade total para as larvas cultivadas no tratamento com ausência constante de alimento. Os resultados sugerem não existir um comportamento lecitotrófico nas zoés de C. major.

Crecimiento y reproducción del camarón Atya margaritacea (Decapoda: Atyidae) en el Río Presidio, Sinaloa, México

Growth and reproduction of the shrimp Atya margaritacea (Decapoda: Atyidae) in Río Presidio, Sinaloa, Mexico. Some growth and reproduction parameters of the population of the shrimp Atya margaritacea in Presidio River (Sinaloa, NW Mexico) were studied using 542 organisms collected with a Surber net in five sampling locations distributed from mid- to low river. Total lengths and gross weights ranged from 15 to 96 mm and 0.1 to 25.2 g. The male:female ratio was 1.96:1 and males had larger sizes and weights. The relations of total length (Lt) to gross weight (Pt) were Pt = 1.02x10-5 (Lt)3.2089 for males and Pt = 2.29x10-5 (Lt)3.0159 for females. Growth in males was positively allometric whereas in females it was isometric. The regressions between total lengths and cephalothorax (Lc) were Log Lc = 1.1118 (Log Lt)- 0.6087 for males and Log Lc = 0.9945 (Log Lt)- 0.4321 for females. The relative growth between these body parts was allometrically positive in males and isometric in females; this result indicates a clear sexual dimorphism. Ovigerous females appeared in the rainy season (July to November). The absolute fecundity ranged from 1 860 to 22 400 eggs in females of 43 to 59 mm in length and 1.9 to 6.0 g in weight. The equations relating the number of eggs to length and weight were Fec = 8.3x10-7 (Lt)5.8053 and Fec = 732 (Pt)1.836 respectively. Rev. Biol. Trop. 56 (2): 513-522. Epub 2008 June 30.

Se estudiaron el crecimiento y reproducción de de Atya margaritacea, con base en 542 organismos capturados en cinco sitios distribuidos desde la parte media de la cuenca hasta la desembocadura del río Presidio (Sinaloa, NW de México). La recolecta se realizó mediante el empleo de una red Surber, recolectándose organismos cuya longitud total y peso total variaron de 15 a 96 mm y 0.1 a 25.2 g respectivamente. La proporción macho:hembra fue 1.96:1 y los machos alcanzaron las mayores tallas y pesos. La relación entre la longitud total (Lt) y el peso total (Pt) se estableció mediante el modelo Pt = 1.02x10-5 (Lt)3.2089 para los machos y por Pt = 2.29x10-5 (Lt)3.0159 para las hembras. El crecimiento en machos resultó alométricamente positivo mientras que en hembras fue isométrico. La regresión entre la longitud total y longitud cefalotórax (Lc) fue Log Lc = 1.1118 (Log Lt)- 0.6087 en machos y Log Lc = 0.9945 (Log Lt)- 0.4321 en hembras. El crecimiento relativo entre estas partes del cuerpo resultó alométrico positivo en machos e isométrico en hembras, indicando un claro dimorfismo sexual de estos organismos. Hembras ovígeras se presentaron en la época de lluvias (julio a noviembre). La fecundidad absoluta varió de 1 860 a 22 400 huevos en hembras de 43 y 59 mm de longitud y de 1.9 a 6.0 g de peso. La ecuación que relacionó el número de huevos con la longitud y peso, fue Fec = 8.3x10-7 (Lt)5.8053 y Fec = 732 (Pt)1.836 respectivamente.

Environmental impact reduction through ecological planning at Bahia Magdalena, Mexico.

For analyzing basic marine and coastal characteristics we selected the potential sites where shrimp culture could be developed in a large coastal zone, Bahia Magdalena, Baja California Sur, Mexico. Based on our analysis, 6 sites were preselected and field stages of work were then developed to assess the precise suitability of each site in order to develop the proposed aquaculture activities. In ranking the suitability we were able to recommend the most appropriate places to develop shrimp culture in this region. Also, knowing the exact biological, physico-chemical and social environment, we determined the best species to cultivate, the recommended total area and the methodology to be used to lessen the environmental impact and to obtain the maximum profitability Our methodology could be used not only to select appropriate sites for shrimp culture in other coastal lagoons, but it also could be applied to assess the suitability in a quick and accurate way, of any other production activity in coastal zones.

Development and functional morphology of the foreguts of larvae and postlarvae of three crustacean decapods

The development of the foregut structure and the digestive function of the decapods Litopenaeus vannamei, Sesarma rectum and Callichirus major larvae and post larvae were examined. The protozoeal foregut of L. vannamei is simple, lacking a cardiopyloric valve and bearing a rudimentary filter press. In mysis, the filter press is more developed. In the juvenile stage, grooves and a small lateral tooth arise. In S. rectum, the foregut has a functional cardiopyloric valve and a filter press. The megalopal and juvenile stages of this species have a gastric mill similar to those in adult crabs. In C. major, the foregut of the zoeae is specialized, with the appearance of some rigid structures, but no gastric mill was found. Calcified structures are observed in the megalopae and they become more developed in the juvenile stage. The results support suppositions, previously reported in other studies, that feeding behavior of each larval and postlarval stage is directly related to the morphological characteristics of the foreguts.

O desenvolvimento da estrutura do estômago e da função digestiva foi examinada em larvas e pós-larvas de Litopenaeus vannamei, Sesarma rectum e Callichirus major. O estômago do protozoea de L. vannamei é muito simples, sem válvula cárdiopilórica e apresenta um filtro pilórico rudimentar. Em mysis, o filtro pilórico parece ser mais desenvolvido. No juvenil I surgem calhas e dentes laterais pouco desenvolvidos. Os estômagos dos zoeae de S. rectum possuem a válvula cárdiopilórica e o filtro pilórico funcionais. Nos estágios megalopa e juvenil I o moinho gástrico é complexo. Em C. major, os estômagos dos zoeae se mostram especializados exibindo algumas estruturas rígidas, mas não apresentam moinho gástrico. Esta estrutura surge no megalopa e juvenil I. Os resultados suportam suposições anteriores que o comportamento alimentar de larvas e pós-larvas está diretamente relacionado com as características morfológicas dos estômagos.

Population biology of the burrowing shrimp Callichirus seilacheri (Decapoda: Callianassidae) in northern Chile

La historia natural de los camarones fantasma, conocidos por modelar la estructura de las comunidades en hábitats de aguas someras, ha sido poco estudiada en el Pacífico suramericano. Aquí presentamos información ecológica concerniente a Callichirus seilacheri, con base en individuos recolectados entre enero y diciembre de 2003 en playa Las Machas, norte de Chile. La densidad de las madrigueras varió entre 1.4 y 20.2 madrigueras / 0.25 m2, y fue mayor durante el verano (18.2 madrigueras / 0.25 m2). La proporción de sexos fue 1:1 durante la mayor parte del periodo de estudio; sin embargo, las hembras superaron en número a los machos en enero y setiembre. Los machos presentaron un tamaño máximo mayor al de las hembras (27.1 y 24.0 mm CL, respectivamente). La presencia de juveniles se restringió principalmente al periodo comprendido entre febrero y mayo. La madurez sexual se alcanza a un tamaño de CL de 20.8 mm en los machos y 18.1 mm en las hembras. El periodo reproductivo principal se extendió del otoño al invierno (de mayo a agosto, con un pico en junio), y coincidió con temperaturas decrecientes en el agua y con la presencia de una capa de sedimento sobre las madrigueras.

The life history of ghost shrimps, known for their role in shaping community structures in shallow water habitats, is poorly studied in species occurring along the coasts of the South American Pacific. Here we present ecological information concerning Callichirus seilacheri based upon individuals collected from January to December 2003 in Las Machas beach, northern Chile. Burrow densities varied between 1.4 and 20.2 burrows / 0.25 m2, and was highest during summer (18.2 burrows / 0.25m2). The sex proportion was 1:1 during most of the study period; however, females outnumbered males in January and September. Males reached a larger maximum size than females (27.1 and 24.0 mm CL, respectively). The presence of juveniles was restricted principally to the time between February and May. Sexual maturity was reached at a size of 20.8 mm (males) and 18.1 mm CL (females). The main breeding period lasted from autumn to winter (May to August, peaking in June), and co-occurred with decreasing water temperatures and the presence of a sediment layer covering the burrows.

Environmental impacts of two kind of ponds for shrimp production at Northwest Mexico.

Aquaculture offers a major opportunity for the economic development of Baja California Sur (BCS), Mexico. The severely limited freshwater supply and the geographic isolation of the state place limits on other productive activities. Despite the aridity, the natural vegetation of BCS is diverse and structurally complex with a high percentage (20%) of endemic species. In this work we compare the environmental impacts produced by two kinds of aquaculture systems: coastal ponds vs. inland ponds. Construction and operation of coastal ponds does not require destruction of the natural vegetation and, as is true for inland ponds. Coastal ponds are also compatible with conservation of mangroves, sea grasses and sensitive habitats for fish and mollusks. To reduce the negative impacts of aquaculture and to protect the vegetation of Baja California Sur, we recommend the use of coastal ponds for shrimp production.

Preliminary identification and quantification of the age-pigment lipofuscin in the brain of Farfantepenaeus paulensis (Crustacea: Decapoda)

A preliminary study was done on the age-pigment lipofuscin content in the brains of captive Farfantepenaeus paulensis juveniles (5 months old) and wild adults (estimated age of 12-15 months). Random samples of 6 individuals were obtained from each group (juvenile and adult) for histological analysis. Serial sections (6 mum) of the brains were mounted without staining and observed in an epifluorescent microscope. The fluorescent images of the five most central sections of the olfactory lobe cell mass (OLCM) of each individual were digitized for image analysis. The lipofuscin granule mean diameter was similar in both groups (p > 0.05), however the lipofuscin area fraction (percentage of the OLCM occupied by pigment granules) was significantly higher (p < 0.05) in the adult shrimp. The detection of lipofuscin granules in 5 month old F. paulensis indicates that lipofuscin deposition probably takes place even earlier in the juvenile phase. Our results suggested that the amount of granules in the F. paulensis OLCM is related to age, but further studies are necessary to evaluate the relationship between lipofuscin content and the age of captive F. paulensis

Inventario de los crustaceos decápodos de las zonas alta y media del Delta del Río Orínoco, Venezuela / Inventory of the decapod custaceans of the high and middle Orinoco River Delta, Venezuela

Con el fin de aumentar el crecimiento sobbre la biodiversidad acuática de Venezuela, se presenta un inventario preliminar de las especies de crustáceos decápados del delta del Orínoco y se discute acerca de sus patrones de distribución. Para esto se estudiaronlas colecciones de camarones carídeos y cangrejos brachiuros depositadas en el Museo de Historia Naturalla Salle y el Museo de Biología de la Universidad Central de Venezuela. Se registran un total de 9 especies de camarones y 7 cagrejos, y es señalada por primera vez para Venezuela la especie Palaemonetes ivonicus, Holthuis, 1952

Nutrición en juveniles del langostino Macrobrachium carcinus (Crustacea: Decapoda) con dietas de residuos vegetales y marinos / Nutrition of juvenile prawn Macrobrachium carcinus (Crustacea: Decapoda) with diets of vegetable and marine residues

Juvenile prawn Macrobrachium carcinus were fed two different diets: restaurant by-products (diet I) and fish and vegetable market by-products (diet II). These diets were evaluated by proximal analysis, assimilation efficiency and the factor conversion rate (FCR). Diet I registered a higher efficiency, but there was no difference in the growth rate. The growth mean (G. L.) for three months was 0.254 +/- 0.13 cm (diet I) and 0.191 +/- 0.1 cm (diet II). The conversion rate was good for both, suggesting that 6 to 7 kg of food are needed to obtain 1 kg of prawn. Survival was 76 PER CENT and 100 per cent for diets I and II, respectively