Invasion History

First Non-native North American Tidal Record: 1967
First Non-native West Coast Tidal Record: 1967
First Non-native East/Gulf Coast Tidal Record: 1969

General Invasion History:

Cuthona perca is often considered native to the tropical Western Atlantic, but a number of scattered global records calls that assumption into question (Ruiz et al. 2000). It was first collected and described in Brazil (Marcus 1958) and is found north through the Caribbean, including Colombia (Marcus 1976) and Jamaica (Edmunds 1964) to Florida (Marcus 1972; Gosliner 1979), South Carolina (Fox and Ruppert 1985), and Chesapeake Bay (Ruiz et al. 2000). In the eastern Atlantic, it has been found in Ghana (Marcus 1977), where it was probably carried in fouling on ships from the Caribbean (Edmunds 1975; Edmunds 1977). It has also been found in the Lagoon of Venice in the Mediterranean (Perrone 1995) and the Black Sea (Martynov et al. 2007). In the Pacific, C. perca is known from California (Carlton 1979; Cohen and Carlton 1995), Hawaii (Gosliner 1979), Japan (Iwasaki 2005; Kashio and Tanaka 2021), and New Zealand (Miller 1977, as C. reflexa). Cuthona perca is potentially transported in fouling and ballast water, and tolerates a wide range of temperature and salinity.

North American Invasion History:

Invasion History on the West Coast:

On the West Coast, Cuthona perca is known only from Lake Merritt, California where it was found in 1967 (Behrens 1991). Lake Merritt is a tidal lagoon in Oakland, on San Francisco Bay. In the lagoon, C. perca feeds on the introduced anemone Diadumene lineata (Carlton 1979; Cohen and Carlton 1995).

Invasion History on the East Coast:

Cuthona perca was first found in Biscayne Bay, near Miami, Florida in 1969 (Marcus 1976). It was later collected in North Inlet, South Carolina where it was associated with the hydroid Pennaria disticha (Fox and Ruppert 1985; Fernando and Kemp 2007). In 1994, it was found on fouling plates at several locations in Norfolk and Lynnhaven, Virginia. It has also been collected at Yorktown, Virginia where it was locally abundant on the introduced anemone Diadumene lineata (Ruiz et al. unpublished data). Its absence in Vogel's (1977) survey indicates that it may be a recent introduction to the Chesapeake.

Invasion History on the Gulf Coast:

In 1975, Joseph L. Simon reported collecting this nudibranch in St. Petersburg, Florida (Gosliner 1979). We have no further records, but presume that it is still established.

Invasion History in Hawaii:

In 1972, Cuthona perca was collected on floating docks in Kaneohe Bay, Oahu, associated with the sea anemone Aiptasia pulchella (Gosliner 1979; Carlton and Eldredge 2009).

Invasion History Elsewhere in the World:

As noted above, Cuthona perca was described from Brazil, near Cananéia (Sao Paulo state), in lagoons adjacent to the Atlantic Ocean (Marcus 1958; Marcus 1977). It was later collected in Santa Marta, Colombia (Marcus 1976) and Jamaica (Edmunds 1964). These records, together with those from Florida, South Carolina and Virginia, are suggestive of native status in the Western Atlantic, but the scattered global records make it difficult to determine its definitive native range. This sea-slug was first collected in the Eastern Atlantic, in Ghana, Africa, in 1975, where it reportedly only occurred on boat hulls (Edmunds 1977). In 1977, a single specimen was found in the Lagoon of Venice, and later identified as C. perca. No further records are known form the Mediterranean (Perrone 1995; Crocetta 2012). However, in 2007, an established population was found in Sevastopol Bay, Ukraine, on the Black Sea: 'intertidal under stones, within old pier'. The animals were feeding on unidentified sea anemones and producing numerous egg masses (Martynov et al. 2007).

In the Pacific, Cuthona perca was reported from Japan in 1993, and is established (Iwasaki 2005; Kahio and Tanaka). It was reported from New Zealand in the 1970’s (Miller 1977, as C. reflexa; Gosliner 1979); however, its identification was questioned by Miller (2004).


Cuthona perca is a slender nudibranch which tapers posteriorly. The tail of illustrated specimens varies in size, from about 10 to 25% of the body length. The body length ranges from 3 to 15 mm. The head is rounded and widened laterally, with oral tentacles that are about 10% of the body length. The rhinophores are slightly longer, and smooth, located in front of a pair of small black eyes. The cerata (dorsal and lateral projecting structures) are spindle-shaped and can be up to 25% of the body length. They form about 8-10 rows, with up to 16 cerata in clusters on each side, decreasing posteriorly. The penis bears a short stylet. The color of the translucent body is light orange to yellowish or off-white, with scatterings of opaque white and black flecks. The core of each cerata is olive-green to reddish-brown with a white tip. Cuthona perca lays its eggs in a kidney-shaped mass, containing about 100 eggs, fastened to a substrate by a stalk (Marcus 1958). Larvae are planktonic for a few days (Kashio and Tanaka 2021); Description from: Gosliner 1979; Behrens 1991; Martynov et al 2007.

Miller (2004) argued that the genus Cuthona should be restricted only to the original type species of the genus, C. nana. Based on differences of digestive morphology, he argued that the rest of the species of the genus should be moved to the genus Trinchesia, but this name is not yet universally accepted. This name is used by some authors (e.g. Martinov et al. 2007). The Integrated Taxonomic Information System treats both names as valid (ITIS 2014).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Gastropoda
Subclass:   Opisthobranchia
Order:   Nudibranchia
Family:   Tergipedidae
Genus:   Cuthona
Species:   perca


Trinchesia perca (Schmekel, 1968)
Catriona perca (Er. Marcus, 1958)
Cuthona perca (Gosliner, 1979)
Cuthona reflexa (Miller, 1977)

Potentially Misidentified Species

Cuthona barbadiana
Cuthona barbadiana Edmunds and Just 1983, was misidentified as Cuthona perca by Marcus and Hughes (1974) (William Rudman, in Australian Museum 2010).

Cuthona reflexa
Cuthona reflexa (Miller 1977) from New Zealand was incorrectly synonymized by Gosliner (1979) and redescribed as a distinct species by Miller (2004).



Cuthona perca is a nudibranch known from estuaries and coastal habitats, including brackish waters. Nudibranchs are simultaneous hermaphrodites and copulate reciprocally or unilaterally. Cuthona perca lays its eggs in a gelatinous mass, attached to a hard substrate. Unhatched veligers rotate inside the eggs which is characteristic of planktotrophic veligers (Martynov et al. 2007). In Brazil, eggs hatched in 8 days at 23-25°C.

Cuthona perca has been reported from lagoons, estuaries, and harbors of warm-temperate to tropical regions. Substrates include rocks, piers, floating docks, and boat hulls (Marcus 1958; Carlton 1979; Gosliner 1979; Martynov et al. 2007). This nudibranch has been found on the introduced Striped Anemone (Diadumene lineata) in Merritt Lagoon (Carlton 1979), on the anemone Aiptasia pulchella in Hawaii (Gosliner 1979), on an unidentified anemone in the Black Sea (Martynov et al. 2007), and on the hydroid Pennaria disticha in South Carolina (Fox and Ruppert 1985). Many nudibranchs which feed on cnidarians, ingest the nematocysts (stinging cells) and incorporate them into their cerata as a defensive mechanism (Barnes 1983). This is probably the case in C. perca.


Sea anemones and hydroids

Trophic Status:




General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatVessel HullNone
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone

Life History

Tolerances and Life History Parameters

Maximum Temperature (ºC)27Field temperature, Sevastopol Bay (Martynov et al. 2007). This nudibranch probably occurs at higher temperatures.
Minimum Salinity (‰)18Typical Black Sea salinity, but C. perca was found near a river mouth, where the salinity might be lower (Martynov et al. 2007).
Maximum Salinity (‰)35Typical Atlantic Ocean salinity
Minimum Length (mm)5Minimum size of animals seen laying eggs (Marcus 1958).
Maximum Length (mm)15Gosliner 1979; Behrens 1991; Martynov et al 2007).

General Impacts

No ecological or economic impacts have been reported for Cuthona perca.

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
SP-XXI None 1972 Def Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 1969 Def Estab
SA-II None 1953 Crypto Estab
CAR-III None 1976 Crypto Estab
WA-II None 1968 Def Estab
NEP-V Northern California to Mid Channel Islands 1967 Def Estab
NA-ET3 Cape Cod to Cape Hatteras 1994 Def Estab
CAR-II None 0 Crypto Estab
MED-VII None 1977 Def Unk
M130 Chesapeake Bay 1994 Def Estab
S200 Biscayne Bay 1969 Def Estab
P090 San Francisco Bay 1967 Def Estab
NWP-3a None 1993 Def Estab
MED-IX None 2007 Def Estab
G070 Tampa Bay 1975 Def Estab
CAR-VII Cape Hatteras to Mid-East Florida 1985 Def Estab
S060 Winyah Bay 1985 Def Estab
EA-V None 1986 Def Unk
NWP-3b None 2019 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
2884 Ruiz et al., unpublished data 1995 1995-01-01 Scott Creek (Hampton Roads) Def 36.5110 -76.3083
2885 Ruiz et al., unpublished data 1995 1995-01-01 Lynnhaven Bay Def 36.8886 -76.0764
2888 Ruiz et al., unpublished data 1996 1995-01-01 Army Dolphin, Norfolk Harbor Def 36.8911 -76.2622
2889 Marcus 1972 1969 1969-01-01 Biscayne Bay Def 25.5656 -80.2167
2890 Edmunds 1964 1964 1964-01-01 Kingston Harbor Crypto 18.2500 -77.5000
2891 Gosliner 1979 1972 1972-01-01 Coconut Island, Kaneohe Bay Def 19.7328 -155.0719
2892 Carlton 1979; Cohen and Carlton 1995 1967 9999-01-01 Lake Merritt Def 37.8044 -122.2697
2894 Ruiz et al., unpublished data 2000 2000-09-25 Belle Isle Marina Def 37.0964 -76.2920
2896 Ruiz et al., unpublished data 2000 2000-09-27 East River, Mobjack Bay Def 37.4046 -76.3467
2899 Ruiz et al., unpublished data 2001 2001-09-10 Norfolk Naval Station/ Def 36.9413 -76.3298
2903 Ruiz et al., unpublished data None 2000-09-27 Gloucester Point Def 37.2477 -76.6662
2904 Ruiz et al., unpublished data 2001 2001-09-04 Waterside Marina Def
2905 Ruiz et al., unpublished data 2001 2001-09-06 York River Yacht Haven Def
2906 Ruiz et al., unpublished data None 2001-02-06 Mobjack Bay Def
2907 Ruiz et al., unpublished data None 2001-08-05 Willoughby Bay Def


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