Cryphiops caementarius

Abstract: 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.

Abstract: Cryphiops caementarius (Molina 1782) (Decapoda: Palaemonidae) the northern freshwater prawn (Fig. 1) is the only species in the famliy represented in Chile. Its geographical distribution is confined to the rivers of the occidental coast of Peru and Chile from 10oS to 32o 55´S. This freshwater prawn in Chile inhabits the rivers and ravines that mainly brought waters from the Andes mountains. The species was protected in Chile during a long time by a total interdiction. However, the clandestine exploitation with an excessive extraction produced a reduction of the population size of this prawn and the reduction of the size of the extracted animals. The damage caused on this resource encouraged the authorities to review the current regulations, proclaming a decree during 1996 with a new disposition that banned the

Abstract: 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.