Caprella simia

Invasion History

First Non-native North American Tidal Record: 2000
First Non-native West Coast Tidal Record: 2000
First Non-native East/Gulf Coast Tidal Record:

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General Invasion History:

Caprella simia is native to the Northwest Pacific from Hong Kong to (at least) Pusan, Korea and the Boso Peninsula, east of Tokyo (Mayer 1903; Kim and Lee 1978; Takeuchi et al. 1990). Its range may extend further north, but we have not been able to find many records for this species. In 2000, it was collected in Long Beach Harbor California (Cohen et al. 2002; Ashton personal communication 2007), and individuals have been present in San Francisco Bay since 2007 (Gail Ashton, personal ocmmunication; Foss 2011).

North American Invasion History:

Invasion History on the West Coast:

In 2000, one specimen of Caprella simia was collected in Long Beach Harbor, in a rapid assessment survey of Southern California (Cohen et al. 2002; Cohen et al. 2005). In 2007, Dr. Gail Ashton collected specimens from a single site in San Francisco (Gail Ashton, personal communication). In 2010, C. simia was found to be widespread in San Francisco Bay (Foss 2011). Caprella simia, like other caprellids, is easily transported in ballast water or hull fouling on ships.

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Description

Caprellid amphipods have a greatly modified body form, when compared to more familiar gammarid amphipods. The body is elongated (giving rise to the name 'skeleton shrimp'), though the abdomen is compressed. The head is partly fused with the first thoracic segment (called Pereonite 1 in amphipods). The head bears a pair of long antennae 1, somewhat shorter antennae. The 1st antennae (A1) have a 3-segmented peduncle, tipped by a flagellum with multiple segments. The 2nd antennae (A2) may be fringed with long setae, and have 3-4 segments in the peduncle, and a shorter flagellum, usually of 2 segments. A mandibular palp of several segments is present in some genera, arising between the antennae, but this is absent in Caprella. There is a small pair of gnathopods, with small grasping claws with a movable finger (Gnathopod 1) , on Pereonite 1. Pereonite 2 bears a much larger pair of gnathopods (Gnathopod 2), which may have conspicuous spines or setae. Pereonites 3 and 4 usually have round or club-shaped gills, while in most species, including Caprella, pereiopods are absent. Pereiopods 5, 6, and 7 are roughly equal and hook-like, for climbing and attachment, with 6 segments. Females develop oostegites, plates which form a brood pouch. Males are usually larger than females of the same species. Females and immature males can be hard to identify to species level. (Description from: Barnes 1983; Watling and Carlton, in Carlton 2007).  

Adults of Caprella simia range from 6-17 mm in length. Both sexes are distinguished by an elongate body shape and a sharply pointed, forward-pointing dorsal spine on the head. Antenna 1 is 2/3 or more of the body length. Antenna 2 is a little shorter than the peduncle of the Antenna 1. The propodus of Gnathopods 1 have a palm covered with setae, and have grasping spines. Pereonite 2 is the longest segment of the body. Gnathopods 2 are attached near the posterior end of pereonite 2. The propodus of Gnathopod 2 is elongate, with one grasping spine, 2 spinules, a long poison tooth, and a blunt triangular projection. The gills are long and elliptical. Pereopods 5 - 7 have a propodus with grasping spines. Description from: Kim and Lee 1978; Watling and Carlton, in Carlton 2007; Ashton 2012d. The available descriptions refer largely to males. Females are probably smaller, and have less-developed gnathopods.

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Taxonomy

Ecology

General:

Life History - Males and females are morphologically distinct. The males are probably larger, more robust, and armed with larger gnathopods. This is likely an adaptation to competition for females and for guarding themselves during molting, which proceeds mating. The young are brooded by the female in an egg-pouch formed by large plates (oostegites) on the 3rd and 4th pereionites (Turcotte and Sainte Marie 2009). Development is direct, with the newborn juveniles having the general form of the adults.

Ecology - Caprellids can feed in a variety of ways, including filtering small particles from the water, browsing on small filamentous algae, scraping tissue from large algae, scavenging, and predation (Turcotte and Sainte Marie 2009). Caprella simia has been found on seaweeds, and manmade structures such as pilings and floating docks (Takeuchi et al. 1990; Foss 2011). One population in Japan was found associated with a red seaweed (Gelidium amansii), but was most abundant in June-September when the algae was undergoing more rapid growth, and rare during the colder months (Takeuchi et al. 1990). We have not found experimental information on the temperature and salinity tolerances of C. simia.

Food:

Phytoplankton; Detritus

Trophic Status:

Suspension Feeder

SusFed

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Habitats

General Habitat	Marinas & Docks	None
General Habitat	Rocky	None
General Habitat	Grass Bed	None
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Epibenthic	None

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Tolerances and Life History Parameters

Maximum Length (mm)	22	Mayer 1890, cited by Kim and Lee 1978
Broad Temperature Range	None	Warm temperate
Broad Salinity Range	None	Polyhaline-Euhaline

General Impacts

Caprella simia is common and widespread in Long Beach Harbor and San Francisco Bay. However, no economic or ecological impacts have been reported.

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References

Ashton, Gail 2012d LifeDesks- <i>Caprella simia</i>, Mayer 1903. <missing URL>



Baldwin, Andy; Leason, Diane (2016) Potential Ecological impacts of Emerald Ash Borer on Maryland's Eastern Shore, In: None(Eds.) None. , <missing place>. Pp. <missing location>

Barnes, Robert D. (1983) Invertebrate Zoology, Saunders, Philadelphia. Pp. 883

California Department of Fish and Wildlife (2014) Introduced Aquatic Species in California Bays and Harbors, 2011 Survey, California Department of Fish and Wildlife, Sacramento CA. Pp. 1-36

Carlton, James T. (Ed.) (2007) The Light and Smith Manual: Intertidal Invertebrates from Central California to Oregon Fourth Edition, Completely Revised and Expanded, University of California Press, Berkeley. Pp. <missing location>

Carlton, James T., Geller, Jonathan B. (1993) Ecological roulette: the global transport of nonindigenous marine organisms., Science 261: 78-82

Cohen, A. N. and 11 authors (2005) Rapid assessment survey for exotic organisms in southern California bays and harbors, and abundance in port and non-port areas., Biological Invasions 7: 995-1002

Cohen, Andrew N. and 10 authors (2005) <missing title>, San Francisco Estuary Institute, Oakland CA. Pp. <missing location>

Cohen, Andrew N. and 12 authors (2002) Project report for the Southern California exotics expedition 2000: a rapid assessment survey of exotic species in sheltered coastal waters., In: (Eds.) . , Sacramento CA. Pp. 1-23

Foss, Stephen (2011) <missing title>, California Department of Fish and Game, Office of Spill Prevention and Response, Sacramento. Pp. 54

Huang, Zongguo (Ed.), Junda Lin (Translator) (2001) Marine Species and Their Distributions in China's Seas, Krieger, Malabar, FL. Pp. <missing location>

Kim, H. S.; Lee, K. S. (1978) Systematic study of Amphipoda (Crustacea) in Korea: Four unrecorded caprellids (Caprellidae) from South Korea., Korean Journal of Zoology 21: 1-7

Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

Ruiz, Gregory; Geller, Jonathan (2021) Spatial and temporal analysis of marine invasions: supplemental studies to evaluate detection through quantitative and molecular methodologies, Marine Invasive Species Program, California Department of Fish and Wildlife, Sacramento CA. Pp. 153 ppl.

Takeuchi, Ichiro; Yamakawa, Hiroshi; Fujiwara, Masamu (1990) Density fluctuations of caprellid amphipods (Crustacea) inhabiting the red alga Gelidium amansii (Lamouroux) Lamouroux with emphasis on Caprella okadai, La Mer 28(1): 30-36

Turcotte, Christian; Sainte Marie, Bernard (2009) Biological synopsis of the Japanese skeleton shrimp Caprella mutica, Canadian Manuscript Report of Fisheries and Aquatic Sciences 2903: 1-26

Watling, Les; Carlton, James T. (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of California, Berkeley CA. Pp. 618-629

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