Shasta Crayfish

P. fortis is thick and stocky, with relatively heavy chelae. It is usually dark brown dorsally with bright orange areas on its underside. These colors aid in camouflage in its habitat. It grows about 2-4 inches long. It lives in cold, clear, rocky areas of the mountain rivers, and feeds on microbes, algae, and small animals like snails. The animal requires a constant, steady, and untainted flow of fresh water to survive. P. fortis have 5 pairs of legs. With regards to life span, P. fortis tends to endure a life span of between 10 and 15 years on average. Females meet their reproductive maturity at the age of five, and after which reproduce once per year. In October, females typically produce anywhere from 10 to 70 eggs per year, with the older more mature females producing the most eggs and the younger females producing at the lower end. By May, most eggs will have hatched and the babies stay attached to their mother for a short duration before separating and becoming a free-willed organism. P. fortis is nocturnal and remain idle behind cover for the majority of the day. They begin to leave their cover only when it is night and light is scarce. …

Pacifastacus fortis is listed as a critically endangered species on the IUCN Red List, and an endangered species under the Endangered Species Act. Numerous factors play a role in the endangerment of P. fortis. Within California, some minor factors include but are not limited to illness and invasive predators. However, human intervention affects the species at a much greater proportion. Urbanization, pollution, and other forms of intervention often affect the surroundings of P. fortis, ultimately resulting in significant habitat loss and consequently, a significant decrease in population. It has always had a very small native range, and that range has been significantly fragmented by such human activities as damming, mining, and agriculture. The Pit River Fish Hatchery was closed to protect this species. Other nonnative invasive crayfish species such as Pacifastacus leniusculus and Orconectes virilis, as well as water impoundment and diversion have contributed to the continuing decline of P. fortis. Chemicals from agriculture have also washed into streams, and groundwater has been pumped to the point of lowering the water table, further decreasing the numbers of P. fortis over the last three decades. …