BIOTIC

BIOTIC Species Information for Gammarus insensibilis

Researched by

Nicola White

Data supplied by

MarLIN

Refereed by

Dr Martin Sheader

Taxonomy

Scientific name

Gammarus insensibilis

Common name

Lagoon sand shrimp

MCS Code

S476

Recent Synonyms

None

Phylum

Crustacea

Subphylum

Superclass

Class

Eumalacostraca

Subclass

Peracarida

Order

Amphipoda

Suborder

Gammaridea

Family

Gammaridae

Genus

Gammarus

Species

insensibilis

Subspecies

Additional Information

As the species is morphologically close to Gammarus locusta it may be under-recorded in parts of its range.

Taxonomy References

Howson & Picton, 1997, Lincoln, 1979, Sheader & Sheader, 1985, Sheader & Sheader, 1987,

General Biology

Growth form

Articulate

Feeding method

Herbivore

Mobility/Movement

Swimmer
Crawler

Environmental position

Epifaunal

Typical food types

Chaetomorpha

Habit

Free living

Bioturbator

Not relevant

Flexibility

Low (10-45 degrees)

Fragility

Intermediate

Size

Small(1-2cm)

Height

Insufficient information

Growth Rate

Insufficient information

Adult dispersal potential

100-1000m

Dependency

Independent

Sociability

Solitary

Toxic/Poisonous?

General Biology Additional Information

This species is often found in dense populations.

Biology References

Distribution and Habitat

Distribution in Britain & Ireland

In England, distribution is restricted to the central southern coast with two isolated east coast sites. Not recorded west of Fleet in Dorset and is absent from the lagoons of Cornwall.

Global distribution

South from the English Channel along the Atlantic coasts of Europe to the Mediterranean and in the Black Sea.

Biogeographic range

Not researched

Depth range

Restricted to depth of lagoons; 2-3 m max.

Migratory

Non-migratory / Resident

Distribution Additional Information

Distribution is restricted to southern parts of England and probably represents the northern limit of the species' range. Found in Dorset, Hampshire, Sussex, Isle of Wight, Essex and Kent in the south and isolated sites in Lincolnshire and Suffolk on the east coast.
The species was present in Widewater lagoon, Sussex, but has not been recorded there since 1979.
Other habitat characteristics are: a regular tidal input of seawater; a small tidal range; no or low freshwater input other than rainfall; water retained at all states of the tide and at all seasons; salinity within the range 10-58 psu, usually 15-35 psu, with seasonal variation.

Substratum preferences

Mud
Muddy sand
Sandy mud

Physiographic preferences

Isolated saline water (Lagoon)

Biological zone

Lower Littoral Fringe

Wave exposure

Very Sheltered
Extremely Sheltered

Tidal stream strength/Water flow

Insufficient information

Salinity

See additional Information

Habitat Preferences Additional Information

Distribution References

Lincoln, 1979, Sheader & Sheader, 1985, Sheader & Sheader, 1987, Anonymous, 1999(s),

Reproduction/Life History

Reproductive type

Gonochoristic

Developmental mechanism

Direct Development

Reproductive Season

All year with summer peak

Reproductive Location

Insufficient information

Reproductive frequency

Annual protracted

Regeneration potential

Life span

<1 year

Age at reproductive maturity

<1 year

Generation time

<1 year

Fecundity

11-100

Egg/propagule size

Insufficient information

Fertilization type

Insufficient information

Larvae/Juveniles
Larval/Juvenile dispersal potential	Not relevant	Larval settlement period	Not relevant
Duration of larval stage	Not relevant

Reproduction Preferences Additional Information

Reproduction continues throughout the year with peak reproductive activity in the warm summer months in the UK. In France, life span varies from 48 to 408 days according to the water temperature when born (Janssen et al., 1979). Those born in the winter develop 4 to 5 times slower than those born in the summer. Egg incubation time also increases with a reduction in water temperature from 7 days in summer to 50 days in winter.

Reproduction References

Janssen et al., 1979,