Invasive Alien Species Fact Sheet – Homarus americanus. – From: Online Database of the European Network on Invasive Alien Species- NOBANIS www.nobanis.org, Date of access x/x/201x.

• Main Authors: I. Meeren, Josianne Støttrup, Mats Ulmestr, Vidar Øresl, Jan Atle, Knutsen A. -l. Agnalt
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: European lobster; Homarus gammarus
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.673.728; http://nobanis.org/files/factsheets/Homarus_americanus.pdf

Species identification Clawed lobster with powerful tail, one pair of long antennae, shorter, branched antennulas, differentiated large claws and four pairs of walking legs. The colouration is usually a dark bluish green to greenish brown, with a reddish tint on body and claws, and a greenish tint on walking legs. It has very dark greenish black spots on carapace and orange to whitish below. Variations in colour composition are common, but white spots near the eyes and mouth, or marbled colouration, commonly found in European lobsters (Homarus gammarus L.1758) are unusual. The protruding rostrum between the eyes has several lateral teeth and usually on or more ventral teeth, which is not found in the European Lobster. In H. americanus the ventral teeth on the rostrum are visible even in the first zoea larval stage (Helluy & Beltz, 1991). The body length can reach 50 cm and body weight can reach up to 20 kg or more, although large specimens are rare (Wollf 1978). See Williams (1987) and Holthuis (1991), for full descriptions. Methods of identifications are described in Jørstad