BIOTIC Species Information for Eurydice pulchra
Researched byLizzie Tyler Data supplied byUniversity of Sheffield
Refereed byThis information is not refereed.
Reproduction/Life History
Reproductive typeGonochoristic
Developmental mechanismOvoviviparous
Reproductive SeasonSee additional information Reproductive LocationAs adult
Reproductive frequencyAnnual episodic Regeneration potential No
Life span1-2 years Age at reproductive maturity
Generation time<1 year Fecundity32
Egg/propagule size Fertilization typeInternal
Larval/Juvenile dispersal potential100-1000m Larval settlement periodNot relevant
Duration of larval stage   
Reproduction Preferences Additional InformationFecundity
The number of eggs carried by females of Eurydice pulchra was reported to vary in populations from different localities. In a population from the Dovey Estuary, west Wales, Fish (1970) observed the total number of eggs in any one female to vary between 22 to 54. Jones (1970) found that small females, 4.5 mm body length, carried a minimum of 10 eggs, whilst larger females, 7 mm body length, carried up to 40 eggs. In France, Salvat (1966) reported females of 6.0 mm body length to carry at least 45 eggs.
Fish (1970) and Jones (1970) describe the reproductive cycle of two British populations of Eurydice pulchra from an estuarine and open coast location respectively. Some differences concerning the duration of the breeding period, number of eggs carried by females of a particular size were found.
The sexes are separate and pair whilst swimming. Development of the embryo occurs within the internal brood pouch (marsupium) of the female, and the incubation period takes 7-8 weeks. Embryonic development is similar to that for other isopods (Forsman, 1944; Kjennerud, 1950; Naylor, 1955b, cited in Fish, 1970), and four distinct stages are recognised, the last stage being a miniature version of the adult. The minimum recorded length of newly emerged juveniles is 1.7 mm and they are able to swim and feed immediately.
Early broods released during July were reported by Jones (1970), to reach maturity before winter within the same year, breed early during the following spring and consequently provide the first broods of that year, before dying in their second autumn after a total life span of approximately 15 months. Broods released in August and September, initially grew as rapidly as the early spring brood but did not reach maturity and consequently overwintered as juveniles. Over-wintering juveniles matured as late as July and themselves produced the late broods of the following year. In contrast, on the west coast of Wales, sexually immature specimens of Eurydice pulchra overwintered twice and took 20 months to attain sexual maturity, produced only one brood per year and had a life span of about 2 years (Fish, 1970). Furthermore, Salvat (1966) reported a population of Eurydice pulchra from Arcachon, France, to have an annual reproductive cycle with sexual maturity being reached within 8 months. It is suspected (Fish, 1970; Jones, 1970; Salvat, 1966), that these variations in reproductive life cycle are related to the significant temperature differences between localities. The effect of temperature being reflected in the duration of the post-hatching growth stages, which are accelerated at higher temperatures.
Reproduction References Fish, 1970, Jones, 1970, Salvat, 1966,
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