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RESUMEN El objetivo de este estudio fue evaluar los efectos de diferentes niveles de dureza total del agua en la muda, calcificación del exoesqueleto, crecimiento y supervivencia de Cryphiops caementarius. Los camarones machos fueron colectados del río Pativilca (Lima, Perú) y cultivados en recipientes individuales dentro de acuarios (55 L). Se emplearon cuatro niveles de dureza total del agua (100, 200, 300 y 400 mg CaCO3 L-1), con tres repeticiones, respectivamente. Los camarones cultivados en agua con dureza de 300 mg L-1 tuvieron menor periodo de muda (26,7 días) y mayor frecuencia de mudas (tres mudas). El contenido de calcio del exoesqueleto del camarón incrementó (p < 0,05) de 25 a 31 % en agua con dureza de 100 y 400 mg L-1, respectivamente. El mayor grosor del exoesqueleto (144 |jm en cefalotórax y 131 μm en abdomen) fue obtenido en agua con dureza de 400 mg L-1 y el menor grosor (93 |jm en cefalotórax y abdomen) en 100 mg L-1. El crecimiento en longitud fue mayor (p < 0,05) en agua con durezas de 200 y 300 mg L-1. El crecimiento en peso fue similar (p > 0,05) entre tratamientos. La mayor supervivencia (> 94,4 %) se mantuvo en agua con durezas de hasta 300 mg L-1 y la menor supervivencia (77,8 %) fue con 400 mg L-1. La dureza total del agua de 200 y 300 mg L-1 es conveniente para el cultivo del camarón, pero dureza del agua mayor o menor a este rango afectan la muda, el crecimiento y la supervivencia por deficiencia o exceso de calcio acumulado, respectivamente en el exoesqueleto del camarón. ABSTRACT The aim of this work was to evaluate the effects of different levels of total hardness on the molting, calcification of exoskeleton, growth and survival of Cryphiops caementarius prawn. Male prawns were collected from Pativilca river (Lima, Peru) and cultivated in individual containers inside aquariums (55 L). Four levels of the total hardness of water (100, 200, 300 and 400 mg CaCO3 L-1) were used, with three repetitions, respectively. Prawns cultured in water with hardness of 300 mg L-1 has a shorter molting period (26.7 days) and a higher frequency of molts (three molts). The calcium content of the prawn exoskeleton increased (p < 0.05) from 25 to 31 % in water with hardness of 100 and 400 mg L-1, respectively. The greatest thickness of the exoskeleton (144 |jm cephalothorax and 131 |jm abdomen) was obtained in water with a hardness of400 mg L-1 and the smallest thickness (93 |jm in the cephalothorax and abdomen) in 100 mg L-1. The growth in length was greater (p < 0.05) in water with hardness of 200 and 300 mg L-1. The weight growth was similar (p > 0.05) between treatments. The highest survival (> 94.4 %) was maintained in water with hardness up to 300 mg L-1 and the lowest survival (77.8 %) was at 400 mg L-1. The total hardness of 200 and 300 mg L-1 is suitable for prawn farming, but hardness high or lower than this range affects the molting, growth and survival due to deficiency or excess of accumulated calcium, respectively, in the prawn exoskeleton.

Throughout the last decade, crustacean aquaculture has been developing rapidly worldwide and has given rise to a growing global trend demanding freshwater native species that share both, socio-economic importance and commercial interest such as subtropical and temperate palaemonids. Unfortunately, the reduction of native populations and the partial or complete absence of ovigerous females during the months of autumn and winter are serious obstacles towards a successful, responsible, and profitable cultivation of such palaemonid species. When reviewing the natural environment at the start of the reproductive season, an increase in both, water temperature and daylight is easily perceived, thus we decided to investigate their effects (temperature and photoperiod) on the ovarian maturation in a subtropical freshwater palaemonid of commercial interest (Cryphiops caementarius) with promising results for a strong and prosperous commercial cultivation. Adult females of C. caementarius were randomly distributed among four treatment groups (G1, G2, G3, and G4). The study was developed in two phases, an initial conditioning phase in which the four treatment groups were exposed to winter environmental conditions for 42 days (photoperiod 10 L:14D, temperature 13 °C) and a final test in which each group was exposed to a specific combination of photoperiod and temperature for a term of 105 days: G1-winter photoperiod and winter temperature (10 L:14D, 13 °C), G2-summer photoperiod and summer temperature (14 L:10D, 25 °C), G3-summer photoperiod and winter temperature (14 L:10D, 13 °C), G4- winter photoperiod and summer temperature (10 L:14D, 25 °C). All the females were individually marked and the events of maturity and spawning were monitored. Maturity events were not recorded in any of the treatment groups exposed to winter temperatures, while 39 % and 31 % of the females exposed to summer temperatures in G2 and G4 respectively, had at least one maturity event during the testing phase. The results obtained suggest that an increase in temperature could be the environmental cue responsible for triggering the process of ovarian maturity in C. caementarius and that an adequate thermal control would allow the production of ovigerous females during the winter months. Controlling crustacean reproduction in captivity using environmental variables instead of invasive techniques such as eyestalk ablation or hormone injection opens a feasible path towards recovering natural populations and/or consolidating commercial farming through friendly aquaculture procedures.

The prawn (Cryphiops caementarius) is the only resource in the Peruvian coastal rivers that supports a commercial fishery. Bioeconomic-fishing aspects are reported based on data (fishing, costs and income derived from fishing) acquired in situ monthly in four altitudinal strata (every 200 meters above sea level - masl) of the Majes-Camaná river during 2019. The catch per unit of effort (CPUE) was expressed in kg h-1, monthly income was estimated based on the average catch values, number of tasks and price of the resource. To evaluate the profitability of the activity of an average fisherman (by stratum), a cash flow based on income and expenses was executed under situations with a constant future, using economic profitability indicators such as the Net Present Value (NPV), Internal Rate of Return (IRR), Benefit-Cost ratio (B/C) and Discounted Payback Period (DPB). There was a predominance of the diving method, the catches (kg) and the fishing yield increased throughout the fishing period (April-December) with a maximum value of 4.8 kg h-1 (December - high strata). Investment costs per fisherman were low, roughly 1,000 soles. The sale price increases with altitude, decreasing over the course of the year depending on the availability of the resource; the monthly income per fisherman varied from 964 soles (April - low stratum) to 6,760 soles (December - high stratum). The economic simulation model showed that the income exceeded the costs of the fishing activity from the first year of activity in all the altitudinal strata, the economic profitability indicators showed high profitability for the activity.

Introduction: Cryphiops caementarius, is an endemic prawn from river ecosystems in Southern Perú and Northern Chile. In these watersheds, natural populations are threatened by multiple anthropic interventions such as mining activities and fishing pressure, but also, by increasing impacts of invasive exotic predators. Information related with predation on C. caementarius is scarce representing a major knowledge gap to ensure suitable management and conservation practices. Accordingly, the further deepening in relevant aspects such as the estimation of populations losses due to predators has been indicated as critical by relevant agencies as FAO. Objective: To conduct a complete registry and classification of C. caementarius predators, updating the knowledge for the Andean region. Methods: A thorough bibliographic review on existing information on C. caementarius' predators from Perú and Chile was carried out calculating percentage of occurrence, relative frequency of species, zoogeographic origin, trophic structure, phenotypic attributes, river zone that inhabits and life stage of incidence. The registry was complemented using semi-structured interviews from prawn´s fishers in central-Northern Chile. Results: C. caementarius is predated along the entire fluvial network (estuary, potamon and rhithron) by 21 species of opportunists, carnivores, omnivores and herbivores, mostly aquatic vertebrates. In turn, these belong to 15 families and six guilds of native, exotic and cosmopolitan species. Approximately 86 % predate on adult prawns, whilst, 71 % on juveniles and 24 % on larvae. More than 40 % of the predation pressure seems to be exerted by native waterfowls and 24 % by exotic fish. Conclusions: The results emphasize the relevance for conservation of native species of predators in the Andean region and the need of control measures on exotic species in a latitudinal basis. Accordingly, this review may serve as an initial decision-making tool for future conservation efforts both on prawns and native biota, but also supporting restocking actions, fisheries management plans and risk assessment for C. caementariuspopulations across the Andean region. Introducción: Cryphiops caementarius es un camarón endémico de los ecosistemas fluviales del sur de Perú y norte de Chile. En estas cuencas hidrográficas, las poblaciones naturales están amenazadas por múltiples intervenciones antrópicas, como la actividad minera y presión pesquera, pero también por el creciente impacto de depredadores exóticos invasores. Información relacionada con la depredación sobre C. caementarius es escasa, representando una brecha de conocimiento importante para asegurar apropiadas prácticas de manejo y conservación. En consecuencia, la profundización en aspectos relevantes como la estimación de las pérdidas de población debido a los depredadores, ha sido indicada como crítica por agencias relevantes como FAO. Objetivo: Realizar un registro completo y clasificación de los depredadores de C. caementarius, actualizando el conocimiento para la región Andina. Métodos: Se realizó una revisión bibliográfica exhaustiva de la información existente sobre los depredadores de C. caementarius de Perú y Chile, calculando el porcentaje de frecuencia de ocurrencia y frecuencia relativa para cada especie, además de su respectivo origen zoogeográfico, estructura trófica, atributo fenotípico, zona fluvial que habita y etapa de la vida de incidencia del camarón. El registro se complementó con entrevistas semi-estructuradas a pescadores de camarones del centro-norte de Chile. Resultados: C. caementarius es depredado en diferentes zonas de la red fluvial (estuario, potamon y ritron) por 21 carnívoros, omnívoros y herbívoros, oportunistas y selectivos, en su mayoría vertebrados acuáticos. A su vez, estos se distribuyen en 15 familias y seis gremios, pertenecientes a tres categorías de origen zoogeográfico (nativo, exótico y cosmopolita). Aproximadamente el 86 % de estas especies depreda sobre la fracción adulta, mientras que el 71 % lo hace sobre juveniles y el 24 % sobre estadios larvales. Las aves acuáticas nativas ejercen más del 40 % de la presión depredadora, seguido por peces exóticos con un 24 %. Conclusiones: Los resultados enfatizan sobre relevancia que tiene la conservación de depredadores nativos en la región Andina y la necesidad de medidas de control sobre especies exóticas. En consecuencia, esta revisión puede servir como una herramienta inicial de toma de decisiones para futuros esfuerzos de conservación tanto de camarones como de la biota nativa, pero también apoyando acciones de gestión pesquera y evaluación de riesgos para C. caementarius en toda la región Andina. Palabras clave: depredadores nativos, especies exóticas, crustáceo dulceacuícola, biodiversidad acuática, Sudamérica.

Reyes Avalos, W., Campoverde Vigo, L., Ferrer Chujutalli, K., Sernaque Jacinto, J. 2020. Thermal preference of postlarvae of the river shrimp Cryphiops caementarius previously acclimated to different temperatures. Ecosistemas 29(1):1802. https://doi.org/10.7818/ECOS.1802 Temperature is one of the main environmental parameters that affects growth, reproduction and migration of ectothermic animals. The aim of this research was to determine the thermal preference of the postlarvae of the river shrimp Cryphiops caementarius, previously acclimatized to different temperatures. The postlarvae were collected from the Mala River and acclimatized for 60 days in the laboratory at 19.4 ± 0.6 oC (control), 22, 24, 26, 28 and 30 oC. The experimental thermal gradient system (10 oC to 33 oC) consisted of a PVC gutter (3 m long and 10 cm deep), with 18 compartments. Thermoregulators (100 W) or frozen hydrogel bags were placed on opposite ends of the gutter. The thermal preference was determined with the acute method and the tests were carried out between 08:00 and 14:00 h. The postlarvae acclimatized to 19 oC and 22 oC were moved to compartments with higher temperatures than their acclimatization temperature. The postlarvae acclimatized to 28 oC and 30 oC were moved to compartments with lower temperatures than their acclimatization temperature. The postlarvae acclimatized to 24 oC and 26 oC were moved to compartments with similar acclimatization temperature. The acclimatization temperature had no significant effect (P>0.05) on the thermal preference (23.9 oC to 24.7 oC) of the postlarvae and the final thermal preference was 24.5 oC. We propose, that this thermal preference is taken into account for the culturing this species.

FONDEF: ID15I10353. CONICYT-National Academy Insertion Contest: 79170111. company Vard Aqua Chile S.A..

The variation in saline requirements during larval development of Cryphiops caementarius establishes a particular coexistence in the culture systems between the shrimp larvae, the microalgae and Artemia nauplii. Although the technology for the mass production of freshwater prawn juveniles has advanced positively, the non-commercial availability of an exclusive live feed for amphidromous crustaceans, such as C. caementarius , has created the need to optimize the management of organisms commonly used as feed in the larval culture of marine crustaceans. We investigated the effect of salinity on embryonic development dynamics and the hatching rate of commercial Artemia sp. cysts, including the effect of cooling decapsulated cysts on the hatching rate, and the effect of salinity on the behavior of marine microalgae used as live feed in the larviculture of C. caementarius . The results encourage a sustained and stable production of Artemia nauplii at different salinities, and at the same time, reduce by 80% the daily time used in feeding activities. Also, the information generated in this study adds critical information about activities and procedures for the larviculture of the northern river shrimp, which could be used to improve larval feeding strategies either in C. caementarius or in other amphidromous crustacean species.

Controlling the concentration of bioflocs is one of the main concerns in aquaculture systems with Biofloc Technology (BFT). Biofloc accumulation deteriorates the water quality and can negatively affect the production rates of the farmed river shrimp. This study describes and characterizes the settling velocity distribution of bioflocs generated with the addition of two carbon sources (molasses and chancaca) when applying the BFT for the rearing of the river shrimp Cryphiops caementarius. This study revealed that bioflocs generated with different carbon sources have different settling velocity curves. Regarding the mass fraction settling velocities, there were significant differences (P

The aim was to determine the growth and survival of males of the Cryphiops caementarius shrimp fed with diets supplemented with common salt. Three experimental diets supplemented with 1, 2 and 3% of common salt and a control diet without common salt were used, with three replicates, respectively. Twelve aquariums (55 L) were used and six individual culture containers (284 cm2) installed in two groups of three levels were introduced into each one. In each culture, the container stocked a shrimp, and in total six shrimp per aquarium was randomly stocked. Seventy-two male shrimps (3.87 g in weight) were used. The experiment lasted 90 days. Results indicated that the diet supplemented with 2% of common salt favored the growth in weight of shrimp males, and it was only different (P < 0.05) with the diet with 3% common salt that caused slow growth in weight. Diets with common salt did not affect shrimp survival (P > 0.05).

En base a prospecciones efectuadas en el río Cañete, Perú, en el periodo 2000-2015, se reporta información referente a aspectos biológicos pesqueros y poblacionales delcamarón de río Cryphiops caementarius. Asimismo, se determinaron los parámetros fisicoquímicos de calidad del agua para establecer su relación con la distribución del recurso a lo largo de la cuenca prospectada. Los resultados indican una fracción mínima de ejemplares con tallas superiores a los 120 mm (

In Chile many experiments to artificially produce juvenile Cryphiops caementarius have been carried out in order to obtain enough stock for aquaculture or repopulation in natural habitats. The aquaculture production technology has been developed by the research staff of the Aquaculture Department of the Universidad Católica del Norte, with the aim of enhancing cultivation at commercial level, obtaining a sustainable production, and decreasing the fisheries pressure on natural populations. The latter is now based on the collection of ovigerous female obtained from their natural habitat. The research shows that it is possible to cultivate C. caementarius juveniles in 65 days through 18 zoeal stages.

The present study is a review of the main inland water malacostracan species of northern Chile: Cryphiops caementarius (Molina, 1782). This species sustains the local fisheries in northern and central Chilean hydrographical basins. Cryphiops caementarius, in Chile known as the northern river shrimp, is endemic to rivers west of the Andes Mountains in Peru, and south from Chancay-Lambayeque River and the rivers in the northern Chilean littoral up to 32°55′S. Research on this species in its natural habitat consigned between 1958 to 2008 was directed to population knowledge, including mainly the existing populations in rivers in the Regions of Atacama and Coquimbo. Important advances were also made with regards to the study of the embryonic development, biology, life cycle and reproduction that serve as a basis for the technological development of juvenile production in a controlled environment.

The northern Chilean (18-27°S) inland waters have been poorly studied, because of difficulties in accessing the area, and the aquatic fauna is sculpted by the high conductivity. The few studies that are available are based on fragmented information on shallow mountain ponds associated with saline deposits (“salares”), and shallow ponds and the Loa river. The aim of the present study is provide a review of the malacostracan ecology of northern Chilean inland waters. The information of shallow mountain ponds and lagoons reveals the presence of the amphipods Hyalella fossamanchini and H. kochi. They are only found at low salinity levels (Cryphiops caementarius and the amphipods H. fossamanchini and H. kochi. However the first species is scarce due excessive fisheries activities and habitat fragmentation, whereas there are no studies about amphipods populations. Nevertheless in Loa river these species can be an important prey for introduced salmonids (Oncorhynchus mykiss and Salmo trutta). Similar patterns were observed for other comparable ecosystems in the Andes mountains of Argentina and Peru.

In many species, different male morphotypes usually employ different tactics to access resources. Males with highly developed weapons are expected to fight and possibly incur higher levels of injury than males with less developed weapons, which usually avoid agonistic encounters. Discrete male morphotypes, where some males are very large and feature powerful chelae, have been reported for several large shrimp species, where males show a lobster-like monopolization of resources. During competitive interactions, these large males fight more vigorously than small males and, consequently, it is expected that they accumulate more injuries. Herein, we identified different morphotypes in the river shrimp Cryphiops caementarius, and we compared the percentage of body damage between large and small shrimps. We measured 26 morphometric data and 6 intensities of color on the chelipeds. Multivariate analysis based on a combination of morphometric and color data confirmed that there are two morphotypes. The ‘dominant’ morph is characterized by stout teeth on the cutting edges and by dark blue color on the external surface of the major cheliped. The two morphotypes can be distinguished based on the differences in the allometric relationships between several morphologic traits and carapace length. Males from the large morphotype had a higher percentage of injuries on their chelipeds than other males. These results suggest that males from the large morphotype are dominant and compete aggressively for access to resources, a hypothesis to be tested in future, behavioral studies.

Freshwater organisms with an amphidromous life cycle are generally thought to disperse widely through marine planktonic larval stages, but only few studies on genetic population structure of amphidromous shrimp exist. We used a 640-basepair region of the mitochondrial gene cytochrome c oxidase I (Cox1) from the amphidromous river shrimp Cryphiops caementarius from five rivers in northern-central Chile to test whether large distances between estuaries (up to 700 km) limit gene flow between populations and result in genetic differentiation among populations. The results revealed high haplotype diversity with no significant geographical structuring, suggesting that gene flow occurs regularly over several hundreds of kilometres, also connecting populations north and south of the Atacama Desert. Seemingly, the terrestrial barrier is overcome by planktonic larval dispersal through the sea, suggesting wide dispersal rather than “stepping-stone” dispersal between estuaries. The population from the southe...

Reductions of its natural populations have led to recent efforts in small-scale aquaculture of the freshwater prawn Cryphiops caementarius, either for conservation or commercial purposes. However, the lack of knowledge about its nutritional requirements has been one of the major obstacles for its successful culture. Given its importance, this study determines and compares the chemical composition (moisture, ash, crude protein, total lipids and nitrogen free extract) of whole animals and main storage tissues (gonad, hepatopancreas and muscle), of C. caementarius adult prawns from two natural populations. Moreover, the relation of this composition with reproductive and environmental parameters (sex, maturation and habitat) is discussed. The specimens were collected in Limarí and Choapa rivers (Coquimbo, Chile) during reproductive season, and divided into six categories according to capture location, gonad maturation stage, and gender. The chemical composition of whole animals and storage tissues was compared among categories. Significant differences were observed between tissues, sexes, maturity stages and locations. Regarding tissues, the muscle and the gonads were rich in protein, whereas the hepatopancreas had high lipid content. According to results, factors such as sex, habitat and stage of gonad maturation can modify the biochemistry of C. caementarius. Nonetheless, the main chemical variations were observed in tissues involved in regulatory processes (hepatopancreas and gonads), and to a lesser extent in structural tissues (muscle). This is the first study known that reports information about the biochemistry of C. caementarius and its findings may be useful to improve feeding practices in aquaculture.

Research has been in progress for several years on various aspects of the biology and ecology of the freshwater prawn Cryphiops caementarius, an inhabitant of rivers in northern Chile. The commercial value of this prawn fomented the accomplishment of studies on its reproduction and development with the aim of producing juveniles under controlled conditions, to be followed by growout to commercial size in managed culture systems. The present study describes larval culture of this species from eggs of gravid females obtained in the field, from the first developmental stage (Zoea I) through the first juvenile stage. The larvae were cultured at 25 °C in UV sterilized water at variable salinities based on the requirements of the developmental stages. Larvae were fed with Nannochloris, Isochrysis and Artemia nauplii as required. This report describes in detail the 18 larval stages of this prawn, as well as its first juvenile form.

La extraccion indiscriminada y alteraciones del medio natural, han puesto en peligro de extincion al unico Palaemonido dulceacuicola de interes comercial, presente en aguas continentales chilenas. Aun cuando esta situacion, ha despertado el interes en estudios que permitan su reproduccion controlada en cautiverio, actualmente es escaso el conocimiento acerca de aspectos reproductivos basicos de esta especie. Dada su importancia, este trabajo describe y caracteriza el proceso completo de maduracion gonadal en hembras de Cryphiops caementarius , en base a cambios en la morfologia externa e interna del ovario. Hembras adultas extraidas del rio Limari, fueron disectadas y sus ovarios removidos y preparados para analisis histologicos. Tejido fibromuscular divide el tejido gonadal de cada lobulo en sacos ovaricos de forma semiconica (conos de maduracion), al interior del los cuales se encuentran ovocitos en diferentes estados de desarrollo de acuerdo a observaciones microscopicas de tamano, morfologia y tincion con H-E, las celulas reproductoras femeninas se clasificaron en seis tipos, ovogonias (Ov), ovocitos previtelogenicos tempranos (O1), ovocitos previtelogenicos tardios (O2), ovocitos vitelogenicos tempranos (O3), ovocitos vitelogenicos tardios (O4) y ovocitos Maduros (OM). El ciclo de madurez gonadal se dividio en cinco estados segun la cantidad y tipo de ovocitos presentes. Los estados 0 y I, corresponden a desovado y previtelogenesis. Los estados II y III a vitelogenesis temprana y vitelogenesis intermedia, mientras el estado IV corresponde a madurez avanzada. La presencia de ovogonias y ovocitos previtelogenicos junto a ovocitos completamente maduros en el estado de madurez avanzada, refleja la capacidad de esta especie de realizar ciclos consecutivos de madurez en intervalos cortos de tiempo.

Nortern Chile includes the Atacama Desert, which is characterized by scarce, shallow, saline shallow endorheic lakes, small intermittent streams, and a few rivers (Niemeyer & Cereceda, 1984). One of the main rivers of this zone is the Loa River which is 440 km long and is the longest river in Chile. The river basin occupies 33,570 km2. Situated in the Antofagasta region of Chile, it originates in the Andes Mountains, close to Bolivia, and receives flow from four tributaries rivers: the Salado, San Pedro, Toconce, and San Salvador Rivers. The Loa basin contains two reservoirs, the Conchi and Sloman (Pumarino, 1978; Niemeyer & Cereceda, 1984; Gutierrez et al., 1998). Studies of the native Loa aquatic fauna to date have only described the presence of the freshwater shrimp, Cryphiops caementarius (Molina, 1782) (Jara et al., 2006), amphipods such as Hyalella fossamanchini and H. kochi (Gonzalez, 2003), and the native silverside Basilichthys near semotilus; Dyer 2000a,b; Ruiz & Marchant 2004; Vila et al., 2006). Introduced fish taxa in the Loa River and its tributaries include Oncorhynchus mykiss and Salmo trutta (Pumarino, 1978; Wetzlar, 1979; Iriarte et al., 2005). Overall, there is little detailed information about aquatic species, their distribution, population status, and associations in the Loa River.

El objetivo del presente trabajo fue determinar el rendimiento reproductivo de hembras de C. caementarius mantenidas con alimento natural. Se empleó 24 hembras inmaduras (5,2 cm y 2,0 g), acondicionadas en ocho acuarios (45 L) y alimentadas durante dos meses de acuerdo a cada tratamiento, con pota (Dosidicus sp.), almeja (Semele solida), poliqueto (Pseudonereis sp.) y con alimento balanceado. El rendimiento reproductivo de las hembras fue mejorado cuando se alimentó con poliqueto y pota, lográndose la maduración entre 16 y 18 días con alta fecundidad (2627 y 1377 huevos g-1) y fertilidad (2566 y 1364 larvas g-1, respectivamente)., The aim was to determine the reproductive performance of females of C. caementarius maintained with natural food. Twenty four females inmature were used (5,2 cm and 2,0 g), conditioned in eight aquarium (50 l) and fed during two months according to each treatment, with giant squid (Dosidicus sp), clam (Semele solid), polychaete (Pseudonereis sp.) and with balanced. The reproductive performance of females was improved when fed with polychaete and giant squid, achieving maturation between 16 to 18 days with higher fecundity (2627 and 1378 eggs g-1) and fertility (2566 and 1364 larvae g-1, respectively).

El objetivo fue estudiar los efectos de la salinidad sobre el desarrollo de embriones de Cryphiops caementa- rius incubados in vitro. Se utilizaron embriones de desarrollo temprano procedentes de una sola hembra. Se emplearon incubadoras de 400 mL, con 4 tratamientos de salinidades de 0, 10, 20 y 30‰, tres replicas, y 200 embriones cada incubadora. El 80% del agua se renovó frecuentemente. Las salinidades entre 0 y 30‰ no afectaron el desarrollo de los embriones hasta el estadio 6. Las salinidades de 10 y 20‰ ocasionaron retraso del desarrollo de los estadios 7 y 8; y la salinidad de 30‰ ocasionó muerte del estadio 7. En agua dulce el 70,3% de los embriones supervivieron y las larvas fueron normales; en cambio en salinidad de 10‰ el 13,5% y en 20‰ solo 7,9% lograron eclosionar larvas pero con deformaciones., The aim of this work was to study the effects of salinity on the development of embryos of Cryphiops caemen- tarius incubated in vitro. We used embryos of early development, from a unique female. The incubators were of 400 mL, with 4 salinity treatments of 0, 10, 20 and 30 ‰, three replicates, and 200 embryos each incubator. The 80% of the water was renewed frequently. The salinities between 0‰ and 30‰ did not affect the develop- ment of the embryos up to the stage 6. The salinities of 10 and 20 ‰ caused delay of the development of the stages 7 and 8; and the salinity of 30‰ caused death of the stage 7. In freshwater the 70,3% of the embryos survived and larvae were normal; on the other hand in salinity at 10‰ to 13,5% and 20‰ only 7,9% achieved larvae hatch but with deformations.

Con larvas obtenidas de hembras gravidas de Cryphiops caementarius (Molina 1782), se realizo dos experiencias de cultivo entre 1995 y 1997. Estas experiencias fueron disenadas con el proposito de definir una metodologia que permitiera producir juveniles de la especie, utilizando condiciones controladas de temperatura, salinidad y alimentacion. Durante este estudio se determino el desarrollo larval, su duracion y la tasa de supervivencia. La disminucion en la tasa de supervivencia en ambos cultivos fue coincidente con los cambios morfologicos en cada estado de desarrollo. Durante el primer cultivo, el estado de primer juvenil fue alcanzado a los 98 dias. Durante la segunda experiencia, el tiempo empleado en la obtencion del primer estado de juvenil fue de 62 dias. Durante esta, se utilizo un suplemento alimenticio consistente en pescado y huevos de gallina. Otro de los resultados importantes logrados fue el aumento en los valores de sincronia en la metamorfosis, lo cual permitio obtener una importante cantidad de animales metamorfoseados (juveniles) durante el tiempo involucrado en el estudio.

Cryphiops caementarius (Molina 1782) (Decapoda: Palaemonidae), denominado camaron de rio del norte (Fig. 1), es la unica especie de la familia representada en Chile y su distribucion geografica esta restringida a los rios de la costa occidental de Peru y Chile desde los 10oS hasta los 32o 55´S. En Chile, esta especie habita principalmente los rios y quebradas que drenan las aguas de los contrafuertes cordilleranos y estuvo protegida durante un largo tiempo por una veda total. Sin embargo, la explotacion clandestina con extraccion desmedida se mantuvo por anos, llevando a la reduccion del tamano de las poblaciones de este decapodo y a la disminucion de la talla de los ejemplares extraidos. El deterioro de este recurso renovable motivo a la autoridad a revisar la normativa vigente y decretar el ano 1986 una nueva disposicion que impide la extraccion del recurso desde el 1 de diciembre y hasta el 30 de abril de cada ano. Estas normativa aumento el interes por conocer las etapas del ciclo biologico de esta especie. Desde los primeros trabajos sinopticos, numerosos han sido los intentos que se sucedieron en Peru y Chile y que han tenido como objeto estudiar su biologia, reproduccion, condiciones bioecologicas, habitat, composicion poblacional, migraciones, desarrollo larval y algunos realizados para intentar su cultivo artificial. Todos los estudios realizados, tanto en Peru como en Chile, son conducentes a conocer y comprender aspectos basicos y tecnologicos destinados a aportar para el establecimiento de sistemas artificiales de cultivo, que permitan reducir la presion extractiva que se realiza sobre el recurso intentando reemplazarla por una produccion artificial de juveniles. Esta revision pretende incluir la mayor cantidad de informacion disponible, con el proposito de reunir en una sola publicacion aquellos aspectos que permitan sentar bases solidas para comprender su comportamiento y poder reproducir artificialmente a la especie con fines de conservacion y acuicultura.

Sanguijuelas de las dos especies Helobdella duplicata y H. triserialis (ambas Glossiphonidae) parasitan al camarón de río Cryphiops caementarius en río Limarí, Chile. El 47 % de los camarones estaba parasitado por una o ambas especies de hirudíneos. H. triserialis fue encontrada solo en los pleópodos con los mayores valores de prevalencia (42 %), intensidad (2.9) y ámbito (1-11). H. duplicata se encontró solamente en los filamentos branquiales con una prevalencia de 7 % intensidad de 1.7 y un ámbito de 1-4. La longitud total y el sexo del hospedero, explicarían las variaciones de la intensidad y prevalencia de las infecciones. Sin embargo, cuando se considera el sexo del hospedero, la prevalencia solo aumenta con el tamaño de las hembras. Las características morfológicas de las hembras podrían explicar la mayor intensidad de H. triserialis en la base de los pleópodos, algo relacionado a su vez con un mayor desarrollo del abdomen.Leeches (Hirudinea: Glossiphoniidae) associated to Cryphiops caementarius (Decapoda: Palaemonidae) of the Limarí river, Chile. Two leech species were found parasitizing the shrimp Cryphiops caementarius from Limarí river, Chile. These ectoparasites can act as population regulators or development inhibitors in their host; however the biological characteristics of this host-parasite interaction are unknown. We analyze the inter-specific differences of the parasitism and its relation with host size and sex using quantitative descriptors. Abundance, prevalence, intensity and range were estimated with respect to host size and sex. The leeches belong to two species of Glossiphonidae: Helobdella triserialis and H. duplicata. Forty-seven percent of the hosts were parasitized by one or both leech species. H. triserialis was found only in the pleopod of the hosts with the highest prevalence values (42 %), intensity (2.9) and range (1-11). H. duplicata was found only in the branchial filaments with 7 % prevalence, an intensity of 1.7 and a range of 1-4. The host’s total length and sex can explain the variation in leech intensity and infection prevalence. However, when only the host’s sex is considered, prevalence only increased with size in female hosts. Morphological characteristics of the females could explain the greater H. triserialis intensity in the base of the pleopod and would be related to a greater abdomen development. Rev. Biol. Trop. 55 (1): 255-260. Epub 2007 March. 31.

El objetivo del presente estudio fue determinar la interrelación del ciclo de muda, ciclo ovárico y desarrollo embrionario en hembras del camarón de río Cryphiops caementarius. Se emplearon 45 hembras ovígeras de 43 mm de longitud total, y se evaluaron los estados del ciclo de muda, los estados del ovario y los estadios del desarrollo embrionario durante dos ciclos reproductivos sucesivos en el período de baja reproducción (abril – agosto 2010). Los resultados muestran que en todas las hembras ovígeras con ovarios maduros y en aquellas (50 %) con maduración intermedia, hubo interrelación entre el desarrollo embrionario, la maduración ovárica y el ciclo de muda. En cambio, en todas las hembras ovígeras con ovarios inmaduros y en aquellas (50 %) con maduración intermedia, sólo hubo interrelación entre el desarrollo embrionario y el ciclo de muda que culminó con su actual ciclo reproductivo.