Japanese Skeleton Shrimp

Caprella mutica

Report it

If you think you have found an aquatic invasive species:

1. do not return the species to the water
2. take photos
3. note:
   • the exact location (GPS coordinates)
   • the observation date
   • identifying features
4. contact us to report it

On this page

• Origin and distribution
• Identifying features
• Habitat
• Socioeconomic impacts
• Mode of arrival
• Mode of dissemination
• Government action
• For further information

Origin and distribution

The Japanese Skeleton Shrimp is native to eastern Asia. It was first reported in Canada in Prince Edward Island in 1998 and is now found:

• in all the Maritime Provinces
• in Quebec
• on the coasts of British Columbia

Identifying features

• Size: up to 3 centimetres
• Colour: variable from pale orange to red
• Long cylindrical body, males with a long two-segmented neck
• Females carry eggs in a ventral (belly) pouch, which is covered with dark red spots
• Males very hairy on neck and claws

Similar species (native)

There are several native caprellid species that resemble the Japanese Skeleton Shrimp. However, these species grow mainly on natural substrates and are not hairy.

Habitat

Japanese Skeleton Shrimp are often found in abundance on artificial structures such as:

• ropes
• buoys
• artificial reefs
• breakwaters
• mussel aquaculture socks

Like many invasive species, Japanese Skeleton Shrimp reproduces rapidly, has a varied diet and tolerates a wide range of temperatures and salinity.

Socioeconomic impacts

Japanese Skeleton Shrimp infest artificial structures such as buoys and mussel aquaculture socks, sometimes reaching numbers of 100,000 individuals per square metre. They may compete with mussels for food and space.

Mode of arrival

The transport of organisms for aquaculture and by ballast waters are identified as the most plausible vectors of introduction for Japanese Skeleton Shrimp to North America.

Mode of dissemination

Japanese Skeleton Shrimp are moved in residual water (e.g. ballast water) and on gear (e.g. ropes, buoys, aquaculture socks). Eggs and larvae can spread naturally by drifting in ocean currents.

Government action

Scientific research

Fisheries and Oceans Canada is monitoring the distribution of invasive biofouling species (that is, aquatic species that live attached to hard surfaces) on the Atlantic coast to detect new invasions and track the spread of Japanese Skeleton Shrimp.

For further information

• Canadian Science Advisory Secretariat (CSAS) Publications
• Biological synopsis of the Japanese Skeleton Shrimp (Caprella mutica) Fisheries and Oceans Canada -- 2009