BIOTIC Species Information for Gammarus salinus
|Researched by||Georgina Budd||Data supplied by||MarLIN|
|Refereed by||This information is not refereed.|
||Developmental mechanism||Direct Development
|Reproductive Season||Autumn to spring||Reproductive Location||Insufficient information|
|Reproductive frequency||Annual protracted||Regeneration potential||No|
|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|
|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,|