Amphipod (G. tigrinus) (Gammarus tigrinus)

Amphipod (G. tigrinus) Common Names: Tiger scud

Description: Small gammarid amphipod with an accessory flagellae on 1st antennae and a well-developed 3rd uropods. Males usually have a long and curly 2nd antennae, distinct setae on their walking legs, and 2-5 groups of posterior marginal setae on the 2nd basal segment of their 1st antennae. Females have fewer setae on the antennae and pereopods. Males average 10.5 mm and females 7.6 mm long.


Habitat: Native to the Atlantic coast of North America. It was first discovered in Saginaw Bay, Lake Huron in 2002 most likely in ballast water.

Reproduction: Females mature in a few months and reproduces quickly, carrying up to 32 embryos on average. 3-16 generations can occur annually and can be triggered at any time if ambient water temperature increases by 15-16 degrees Celsius.

Impact and Damage: Capable of colonizing waters very quickly and eliminating native species due to predation and food competition.

Credits: The information provided in this factsheet was gathered from the USGS Nonindigenous Aquatic Species database.

Individual species images that appear with a number in a black box are courtesy of the network ( photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (

Common Name:

Amphipod (G. tigrinus)

Scientific Name:

Gammarus tigrinus