El Yunque National Forest

Photo:  B. Yoshioka, US Fish & Wildlife Service

Big-claw River Shrimp (Eng.), Camarón de Río, Langostino (Sp.), Macrobrachium carcinus
Information compiled by Alan Mowbray, Interpretive Media Writer, EYNF/LEF

General Information:
Macrobrachia are from the family Palaemonidae. They are represented by five species; M. carcinus, M. heterochirus, M. acanthurus, M. faustium and M. crenulatum. Three of the species including the Big-claw River Shrimp (M. carcinus) are fished for human consumption and are sold locally. The shrimp are important food sources to each other, native river crabs, fish and wading birds that frequent the stream systems.

Description:
After several years of growth adult M. carcinus can reach up to 18 inches (45.7 centimeters) in length and may weigh up to 1 pound (.45 kilograms).

Habits:
Post-larval shrimp migrate from estuaries to upstream pools. Juveniles and adults are omnivorous and shift their feeding from algae and aquatic insects to larger prey as they increase in size and migrate farther upstream. Both sexes seasonally migrate farther upstream and females are gravid (full of eggs) during periods of low stream flow (December to April). Adults occur in deep-water pools where they shelter during the day.

Habitat:
Post-Larval Adult and young Big-claw River Shrimp migrate upstream to freshwater pools, especially above steep waterfalls where they are less likely to be harvested or devoured by predators.

Where to look for this animal in the EYNF:
Freshwater pools along the La Mina and Mameyes rivers in the EYNF recreational area.

Additional Information:
Biologist
USDA Forest Service
El Yunque National Forest
HC-01 Box 13490
Rio Grande, PR 00745-9625
787-888-5610

U.S. Fish and Wildlife Service
PO Box 491
Boquerón, PR 00622