BIOTIC

BIOTIC Species Information for Gammarus salinus

Researched by

Georgina Budd

Data supplied by

MarLIN

Refereed by

This information is not refereed.

Taxonomy

Scientific name

Gammarus salinus

Common name

A gammarid shrimp

MCS Code

S481

Recent Synonyms

None

Phylum

Crustacea

Subphylum

Superclass

Class

Eumalacostraca

Subclass

Peracarida

Order

Amphipoda

Suborder

Gammaridea

Family

Gammaridae

Genus

Gammarus

Species

salinus

Subspecies

Additional Information

Nine other marine species of Gammarus are found around the British Isles: Gammarus locusta, Gammarus zaddachi, Gammarus oceanicus, Gammarus chevreuxi,Gammarus tigrinus, Gammarus finmarchicus, Gammarus duebeni, Gammarus insensibilis and Gammarus crinicornis (Lincoln, 1979).
Accurate identification of amphipods requires a certain amount of manipulation under a microscope.

Taxonomy References

Lincoln, 1979, Hayward et al., 1996, Ruppert & Barnes, 1994, Kolding, 1981,

General Biology

Growth form

Articulate

Feeding method

Herbivore
Surface deposit feeder

Mobility/Movement

Swimmer
Crawler

Environmental position

Epibenthic

Typical food types

Organic detritus and seaweed.

Habit

Free living

Bioturbator

Not relevant

Flexibility

High (>45 degrees)

Fragility

Intermediate

Size

Small(1-2cm)

Height

Insufficient information

Growth Rate

Insufficient information

Adult dispersal potential

100-1000m

Dependency

Independent

Sociability

Gregarious

Toxic/Poisonous?

General Biology Additional Information

Moulting
Kinné (1960) found that the frequency (days - weeks) at which Gammarus salinus moulted varied with changes in temperature, the intervals being longer in males than in females. Females kept without a male showed a progressive prolongation of the intervals between moults beginning with the 3rd of 4th interval following isolation. Females kept together with males, in pairs, maintained moults at constant intervals. No differences were observed to occur in different salinities of 5, 10 and 30 psu.

Biology References

Lincoln, 1979, Kinné, 1960, Breeman & Hoeksema, 1987,

Distribution and Habitat

Distribution in Britain & Ireland

On all coasts of England, Scotland and Wales in brackish-water, especially in the Humber and Severn Estuaries.

Global distribution

North-west Europe from English Channel to Baltic, some isolated reports of Gammarus salinus on the Iberian Peninsula.

Biogeographic range

Not researched

Depth range

0-10 m

Migratory

Non-migratory / Resident

Distribution Additional Information

Gammarus species are abundant estuarine animals. Spooner (1947) stated that gammarids were adaptable to various surroundings and not limited to particularly specialised ecological niches. Nor did they show gross patchiness of distribution within their habitable range, rather continuous populations occupy the entire length of estuaries, although the proportion of species represented changes from head to mouth. Furthermore, gammarids are relatively indifferent to the nature of the substratum to a remarkable degree. Provided that there is some kind of object to provide them with shelter/cover it does not matter whether the substratum is muddy or stony, the water turbid or clear and almost any kind of organic matter provides detritus upon which to feed (Spooner, 1947).

The distributional range of Gammarus salinus to the south was thought to be restricted as far as the English Channel. However, Van Maren (1975) reported Gammarus salinus for the first time on the Spanish coast in 1974.

Substratum preferences

Algae
Gravel / shingle
Coarse clean sand

Physiographic preferences

Estuary

Biological zone

Upper Infralittoral
Lower Infralittoral

Wave exposure

Sheltered
Very Sheltered
Extremely Sheltered

Tidal stream strength/Water flow

Strong (3-6 kn)
Moderately Strong (1-3 kn)

Salinity

Reduced (18-30 psu)
Low (<18 psu)

Habitat Preferences Additional Information

Distribution References

Lincoln, 1979, JNCC, 1999, NBN, 2002, Maren van, 1975, Crothers, 1966, Spooner, 1947,

Reproduction/Life History

Reproductive type

Gonochoristic

Developmental mechanism

Direct Development

Reproductive Season

Autumn to spring

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

Increases with female length

Egg/propagule size

Insufficient information

Fertilization type

Internal

Larvae/Juveniles
Larval/Juvenile dispersal potential	100-1000m	Larval settlement period	Not relevant
Duration of larval stage	Not relevant

Reproduction Preferences Additional Information

Leineweber (1985) sampled a population of Gammarus salinus over 15 months in the south-western Kattegat at Sangstrup Klint, Denmark and reported that Gammarus salinus most likely had two generations per year, mature females were found from late November to late July. However, in the Limfjord, Denmark, the population of Gammarus salinus was reported to only produce one generation between 1977-1978, despite the presence of egg bearing females throughout the year (Kolding & Fenchel, 1979). Juveniles were most numerous from April through to July, and in the warmer months between July and October a relatively stable population was attained. The main reproduction period occurred during the winter months, with 80% of the female population reported to be pregnant, the adult generation died in May.
During reproduction, the male carries the smaller female grasped by his gnathopods, a condition known as amplexus. The animals separate briefly to permit the final preadult moult of the female. Sperm transfer is accomplished quickly; the male twists his abdomen around so that his uropods touch the female marsupium (brood pouch) and sperm are swept into the marsupium by the ventilating current created by the female. Finally the pair separate (Rupert & Barnes, 1994). The eggs are brooded within a chamber, the marsupium, beneath the thorax, formed by shelf-like plates projecting inward from the thoracic coxae.
Kinné (1960) examined the effects of different temperatures and salinity on the incubation time of Gammarus salinus. At a temperature between 19-20 °C females attained sexual maturity (1st oviposition) 20-30 days after hatching; their average length (from tip of rostrum to base of telson) being 7-8 mm. Males reached maturity one or more weeks later than the females. The incubation time (period between oviposition and hatching) of the eggs depended largely on the temperature at which the females were maintained; < 14 °C incubation took over 15 days and decreased to 5 days at 20 °C. As in other amphipods Kinné (1960) found that the fecundity of females increased with length, with numbers of eggs varying in a clutch (Ruppert & Barnes, 1994).

Reproduction References

Leineweber, 1985, Kinné, 1960, Ruppert & Barnes, 1994, Kolding & Fenchel, 1979,