Chesapeake Bay Introduced Species Database

Cuthona perca

Common name(s):
Lake Merrit Cuthona
Lake Merritt Cuthona is a sea slug (nudibranch). Sea slugs are in the same group as snails (gastropod mollusks) but they don?t have shells and all are aquatic. They have gills that often look like lobes along their sides and backs. Because some species are brilliantly colored, or interestingly shaped, self-taught divers have often played a big role in tracking their distribution and biology. Lake Merritt Cuthona is translucent white with opaque white and olive flecks. Some considered them native to the tropical Western Atlantic, but its present far-flung range calls that assumption into question. They were first collected and described in Brazil in the 1950s but are widely distributed. They have been found in the Caribbean, Jamaica, Colombia, Barbados, Florida, Ghana, the Mediterranean, San Francisco Bay, Hawaii, and New Zealand, just to name a few. In the Chesapeake, they were collected in Norfolk Harbor in 1994 and 1995 and several other locations in the lower Bay indicating that they have become established. Their arrival in the Bay is fairly recent and there are indications that they were introduced in ballast water or through hull fouling. They feed on hydroids and sea anemones, including the introduced Striped Sea Anemone (Diadumene lineata).
Image courtesy of Ruiz laboratory.

Chesapeake Bay Status:

First Record
Regular Resident

Source Region
Native Region
Western Atlantic Unknown-Marine

Vector(s) of Introduction
Shipping(Ballast Water,Fouling Community)

History of Spread:

Cuthona perca (Lake Merritt Cuthona) has usually been considered native to the tropical Western Atlantic, but its present far-flung range calls that assumption into question (Ruiz et al. 2000). It was first collected and described in Brazil (Marcus 1958), and is found north to the Caribbean, including Jamaica (Edmunds 1964), Colombia (Marcus 1976), Barbados, and Florida (Abbott 1974; Marcus 1976; Marcus 1977). In the eastern Atlantic, it has also been found in Ghana (Marcus 1977), where it was probably carried in fouling on ships from the Carribean (Edmunds 1975; Edmunds 1977), and from the Lagoon of Venice in the Mediterranean, where it is presumed to be introduced (Perrone 1995). In the Pacific, C. perca is known from Lake Merritt on San Francisco Bay (Carlton 1979; Cohen and Carlton 1995), from Hawaii (Gosliner 1979), and New Zealand (Miller 1977, as C. reflexa).

Cuthona perca's occurrence in Lake Merritt, San Francisco Bay, where it was first collected in 1967 is clearly an introduction (Carlton 1979; Cohen and Carlton 1995), and the other Pacific records may represent introductions also. On the East Coast of North America, C. perca was first found in Biscayne Bay, near Miami FL, in 1969 (Marcus 1976).

In the Chesapeake, Cuthona perca has been collected from fouling plates in Norfolk Harbor in 1994 and 1995 (Ruiz et al. unpublished data). Its occurrence at several locations suggests that it may be established in the lower Bay. It has also been collected at Yorktown VA, 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.

History References - Abbott 1974; Carlton 1979; Carlton 2000: Cohen and Carlton 1995; Edmunds 1964; Edmunds 1975; Edmunds 1977; Gosliner 1979; Marcus 1958; Marcus 1976; Marcus 1977; Miller 1977; Perrone 1995; Ruiz et al. unpublished data; Vogel 1977

Invasion Comments:

This data was last modified on Tuesday, September 13th, 2005.
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