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Invasion History
First Non-native North American Tidal Record: 2000First Non-native West Coast Tidal Record: 2000
First Non-native East/Gulf Coast Tidal Record:
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.
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.
Taxonomy
Taxonomic Tree
| Kingdom: | Animalia | |
| Phylum: | Arthropoda | |
| Subphylum: | Crustacea | |
| Class: | Malacostraca | |
| Subclass: | Eumalacostraca | |
| Superorder: | Peracarida | |
| Order: | Amphipoda | |
| Suborder: | Caprellidea | |
| Infraorder: | Caprellida | |
| Superfamily: | Caprelloidea | |
| Family: | Caprellidae | |
| Genus: | Caprella | |
| Species: | simia |
Synonyms
Potentially Misidentified Species
Cosmopolitan, a species complex
Caprella scaura
Cosmopolitan, a species complex, introduced to East and West coasts of US
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
SusFedHabitats
| 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 |
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.Regional Distribution Map
| Bioregion | Region Name | Year | Invasion Status | Population Status |
|---|---|---|---|---|
| NWP-3a | None | 0 | Native | Estab |
| NWP-2 | None | 0 | Native | Estab |
| NWP-4a | None | 0 | Native | Estab |
| NWP-3b | None | 0 | Native | Estab |
| NEP-VI | Pt. Conception to Southern Baja California | 2000 | Def | Estab |
| P050 | San Pedro Bay | 2000 | Def | Estab |
| NEP-V | Northern California to Mid Channel Islands | 2010 | Def | Estab |
| P090 | San Francisco Bay | 2010 | Def | Estab |
| P065 | _CDA_P065 (Santa Barbara Channel) | 2011 | Def | Estab |
| P062 | _CDA_P062 (Calleguas) | 2011 | Def | Estab |
| P027 | _CDA_P027 (Aliso-San Onofre) | 2011 | Def | Estab |
| P040 | Newport Bay | 2011 | Def | Estab |
| P058 | _CDA_P058 (San Pedro Channel Islands) | 2011 | Def | Estab |
| P030 | Mission Bay | 2011 | Def | Estab |
| P020 | San Diego Bay | 0 | Def | Estab |
| NEP-III | Alaskan panhandle to N. of Puget Sound | 2008 | Def | Estab |
Occurrence Map
| OCC_ID | Author | Year | Date | Locality | Status | Latitude | Longitude |
|---|---|---|---|---|---|---|---|
| 767386 | Ruiz et al., 2015 | 2012 | 2012-08-15 | Tomales- Call Box 401, Bodega Bay, California, USA | Def | 38.1793 | -122.9104 |
| 767422 | Ruiz et al., 2015 | 2013 | 2013-07-19 | SeaWorld Marina, Mission Bay, CA, California, USA | Def | 32.7676 | -117.2314 |
| 767436 | Ruiz et al., 2015 | 2013 | 2013-07-23 | Marina Village, Mission Bay, CA, California, USA | Def | 32.7605 | -117.2364 |
| 767456 | Ruiz et al., 2015 | 2013 | 2013-07-29 | Mission Bay Yacht Club, Mission Bay, CA, California, USA | Def | 32.7778 | -117.2485 |
| 767476 | Ruiz et al., 2015 | 2013 | 2013-08-04 | Bahia Resort Marina, Mission Bay, CA, California, USA | Def | 32.7731 | -117.2478 |
| 767505 | Ruiz et al., 2015 | 2013 | 2013-08-01 | Hyatt Resort Marina, Mission Bay, CA, California, USA | Def | 32.7634 | -117.2397 |
| 767523 | Ruiz et al., 2015 | 2013 | 2013-08-03 | Mission Bay Sport Center, Mission Bay, CA, California, USA | Def | 32.7857 | -117.2495 |
| 767551 | Ruiz et al., 2015 | 2013 | 2013-08-02 | The Dana Marina, Mission Bay, CA, California, USA | Def | 32.7671 | -117.2363 |
| 767564 | Ruiz et al., 2015 | 2013 | 2013-08-05 | Paradise Point Resort, Mission Bay, CA, California, USA | Def | 32.7730 | -117.2406 |
| 767578 | Ruiz et al., 2015 | 2013 | 2013-08-30 | 201 Main, Morro Bay, CA, California, USA | Def | 35.3564 | -120.8474 |
| 767591 | Ruiz et al., 2015 | 2013 | 2013-08-27 | City Harbor, Morro Bay, CA, California, USA | Def | 35.3709 | -120.8582 |
| 767603 | Ruiz et al., 2015 | 2013 | 2013-09-05 | Launch Ramp, Morro Bay, CA, California, USA | Def | 35.3577 | -120.8508 |
| 767612 | Ruiz et al., 2015 | 2013 | 2013-08-29 | Moorings, Morro Bay, CA, California, USA | Def | 35.3619 | -120.8548 |
| 767625 | Ruiz et al., 2015 | 2013 | 2013-08-31 | Morro Bay Marina, Morro Bay, CA, California, USA | Def | 35.3641 | -120.8532 |
| 767632 | Ruiz et al., 2015 | 2013 | 2013-08-28 | Sealion Dock, Morro Bay, CA, California, USA | Def | 35.3658 | -120.8555 |
| 767655 | Ruiz et al., 2015 | 2013 | 2013-09-04 | Tidelands, Morro Bay, CA, California, USA | Def | 35.3602 | -120.8521 |
| 767665 | Ruiz et al., 2015 | 2013 | 2013-07-16 | Naval Base Point Loma, San Diego Bay, CA, California, USA | Def | 32.6886 | -117.2343 |
| 767676 | Ruiz et al., 2015 | 2013 | 2013-07-17 | Naval Station San Diego, San Diego Bay, CA, California, USA | Def | 32.6867 | -117.1333 |
| 767705 | Ruiz et al., 2015 | 2013 | 2013-07-25 | Navy Ammo Dock, Pier Bravo, San Diego Bay, CA, California, USA | Def | 32.6939 | -117.2276 |
| 767759 | Ruiz et al., 2015 | 2013 | 2013-07-26 | Pier 32 Marina, San Diego Bay, CA, California, USA | Def | 32.6516 | -117.1077 |
| 767783 | Ruiz et al., 2015 | 2013 | 2013-07-28 | Marriott Marquis and Marina, San Diego Bay, CA, California, USA | Def | 32.7059 | -117.1655 |
| 767820 | Ruiz et al., 2015 | 2011 | 2011-09-20 | San Francisco Marina, San Francisco Bay, CA, California, USA | Def | 37.8067 | -122.4432 |
| 767832 | Ruiz et al., 2015 | 2011 | 2011-09-14 | Coyote Point Marina, San Francisco Bay, CA, California, USA | Def | 37.5880 | -122.3160 |
| 767853 | Ruiz et al., 2015 | 2011 | 2011-09-13 | Oyster Point Marina, San Francisco Bay, CA, California, USA | Def | 37.6725 | -122.3864 |
| 767888 | Ruiz et al., 2015 | 2011 | 2012-09-19 | Sausalito Marine Harbor, San Francisco Bay, CA, California, USA | Def | 37.8609 | -122.4853 |
| 767903 | Ruiz et al., 2015 | 2011 | 2011-09-21 | South Beach Harbor, San Francisco Bay, CA, California, USA | Def | 37.7797 | -122.3871 |
| 767915 | Ruiz et al., 2015 | 2011 | 2011-09-20 | Jack London Square Marina, San Francisco Bay, CA, California, USA | Def | 37.7947 | -122.2822 |
| 767949 | Ruiz et al., 2015 | 2011 | 2011-09-12 | Paradise Cay Yacht Harbor, San Francisco Bay, CA, California, USA | Def | 37.9156 | -122.4769 |
| 767964 | Ruiz et al., 2015 | 2011 | 2011-09-12 | Corinthian Yacht Club, San Francisco Bay, CA, California, USA | Def | 37.8103 | -122.3228 |
| 767978 | Ruiz et al., 2015 | 2012 | 2012-08-24 | Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA | Def | 37.9134 | -122.3523 |
| 768002 | Ruiz et al., 2015 | 2012 | 2012-08-23 | Sausalito Marine Harbor, San Francisco Bay, CA, California, USA | Def | 37.8609 | -122.4853 |
| 768018 | Ruiz et al., 2015 | 2012 | 2012-08-28 | San Francisco Marina, San Francisco Bay, CA, California, USA | Def | 37.8071 | -122.4341 |
| 768033 | Ruiz et al., 2015 | 2012 | 2012-08-27 | Port of San Francisco Pier 31, San Francisco Bay, CA, California, USA | Def | 37.8078 | -122.4060 |
| 768055 | Ruiz et al., 2015 | 2012 | 2012-09-11 | Ballena Isle Marina, San Francisco Bay, CA, California, USA | Def | 37.7676 | -122.2869 |
| 768077 | Ruiz et al., 2015 | 2012 | 2012-08-30 | Oyster Point Marina, San Francisco Bay, CA, California, USA | Def | 37.6633 | -122.3817 |
| 768101 | Ruiz et al., 2015 | 2012 | 2012-08-29 | Coyote Point Marina, San Francisco Bay, CA, California, USA | Def | 37.5877 | -122.3174 |
| 768148 | Ruiz et al., 2015 | 2012 | 2012-09-06 | Loch Lomond Marina, San Francisco Bay, CA, California, USA | Def | 37.9736 | -122.4802 |
| 768166 | Ruiz et al., 2015 | 2012 | 2012-09-05 | Port of Oakland, San Francisco Bay, CA, California, USA | Def | 37.7987 | -122.3228 |
| 768189 | Ruiz et al., 2015 | 2012 | 2012-09-07 | Jack London Square Marina, San Francisco Bay, CA, California, USA | Def | 37.7940 | -122.2787 |
| 768245 | Ruiz et al., 2015 | 2012 | 2012-09-12 | Emeryville, San Francisco Bay, CA, California, USA | Def | 37.8396 | -122.3133 |
| 768268 | Ruiz et al., 2015 | 2013 | 2013-08-15 | Ballena Isle Marina, San Francisco Bay, CA, California, USA | Def | 37.7656 | -122.2858 |
| 768291 | Ruiz et al., 2015 | 2013 | 2013-08-20 | Coyote Point Marina, San Francisco Bay, CA, California, USA | Def | 37.5877 | -122.3163 |
| 768311 | Ruiz et al., 2015 | 2013 | 2013-08-22 | Jack London Square Marina, San Francisco Bay, CA, California, USA | Def | 37.7926 | -122.2746 |
| 768350 | Ruiz et al., 2015 | 2013 | 2013-08-13 | Oyster Point Marina, San Francisco Bay, CA, California, USA | Def | 37.6639 | -122.3821 |
| 768394 | Ruiz et al., 2015 | 2013 | 2013-08-19 | Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA | Def | 37.9138 | -122.3522 |
| 768414 | Ruiz et al., 2015 | 2013 | 2013-08-12 | San Francisco Marina, San Francisco Bay, CA, California, USA | Def | 37.8078 | -122.4354 |
| 768446 | Ruiz et al., 2015 | 2013 | 2013-08-16 | Sausalito Marine Harbor, San Francisco Bay, CA, California, USA | Def | 37.8611 | -122.4851 |
References
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Foss, Stephen (2011) <missing title>, California Department of Fish and Game, Office of Spill Prevention and Response, Sacramento. Pp. 54
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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
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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