NOBANIS - Marine invasive species in Nordic waters - Fact Sheet

Distribution
Native distribution
This is a cryptogenic species. It was originally described from Helgoland in 1847 (Bakken &
Wilson, 2005), but it took almost 100 years before it was recorded in other places. However, Wolff
(1973) claims that it may have been present in the Netherlands since the 18th century, and there are
museum records from 1899.
Introduced distribution
This species is found almost worldwide, but has been considered native of the North(east) Atlantic
and then introduced to other regions. It was first recorded from Danish waters in 1953, but later a
few specimens, which had been collected in 1949, were found in the Zoological Museum,
Copenhagen (Muus, 1967). It was first found in Sweden on the west coast in 1940 (Smith, 1963). It
is often associated with mussel beds (Muus, 1967; Rasmussen, 1973).
On the west coast of the USA N. succinea lives in a land-locked salt-lake, Salton Sea, below sea
level (Kuhl & Oglesby, 1979).
The species recorded as Nereis succinea in the Caspian Sea has turned out to be Hediste
diversicolor (=Nereis d.) (Muus, 1967).
Neanthes succinea occurs in Iranean Gulf (as Nereis alatopalpis) and in southeastern Australia,
where it was first recorded in 1978 (Hewitt et al., 2004).
Ecology
N. succinea is a deposit-feeder preferentially inhabiting soft bottoms from intertidal to about 20 m
depth (Wolff, 1973). It may also be a voracious predator or scavenger, feeding on amphipods or
other small invertebrates (Rasmussen, 1973; Hardege et al., 1990). It burrows in the sediment and
may form semi-permanent U-shaped tubes or complex gallery burrows, depending on the sediment
(Rasmussen, 1973; Kirkegaard, 1992). It may occur in densities of 600 individuals per m²
(Rasmussen, 1973). It is highly tolerant for kinds of pollution and extremely euryhaline (Kuhl &
Oglesby, 1979) and is able to take up sediment-associated pollutants through the gut (Ahrens et al.,
2001). It is often associated with mussel and oyster beds. It is an excellent food for many fish
species (Carpelan & Linsley, 1961; Neuhoff, 1979), and is also used for bait by sport fishermen.
During swarming they are often prey of sea birds from above and jellyfish from below (Rasmussen,
1973).
Reproduction
In N. succinea both sexes show swarming behavior in connection with reproduction. Swarming
takes place in the summer at temperatures above 13° C, and usually during the night at new moon
(Kirkegaard, 1992), though it occurred in bright sunshine in the Isefjord (Rasmussen, 1973). The
the Salton Sea swarming does not seem to follow a monthly cycle (Carpelan & Linsley, 1972). In
N. virens only the males form “heteronereis” or epitoke body forms with enlanrged parapodial lobes
on part of the body (Bass & Brafield, 1972). H. diversicolor does not change in body form in
connection with reproduction (Kirkegaard, 1992). In all three species the worms die soon after
spawning (Muus, 1967; Kirkegaard, 1992). Spawning period for N. succinea is June to September,
for N. virens April to May, and for H. diversicolor June to August (Neuhoff, 1979). Gonads mature
while the animals are still in their tubes while they wait for the adequate signal to initiate swarming