BIOTIC

BIOTIC Species Information for Echinus esculentus

Researched by

Dr Harvey Tyler-Walters and Lizzie Tyler

Data supplied by

MarLIN and University of Sheffield

Refereed by

This information is not refereed.

Reproduction/Life History

Reproductive type

Gonochoristic

Developmental mechanism

Planktotrophic

Reproductive Season

Spring

Reproductive Location

Water column

Reproductive frequency

Annual episodic

Regeneration potential

Life span

6-10 years

Age at reproductive maturity

1-2 years

Generation time

1-2 years

Fecundity

20000000

Egg/propagule size

Fertilization type

External

Larvae/Juveniles
Larval/Juvenile dispersal potential	>10km	Larval settlement period
Duration of larval stage	1-2 months

Reproduction Preferences Additional Information

Nichols (1979) estimates the maximum life span to be between 8-10 years, whereas Gage (1992a) reports a specimen (based on growth bands) of at least 16 years of age.
The number of eggs produced will vary with location and nutritive state of the adult but it is likely to be high. MacBride (1903) states that a well-grown female contains about 20 million eggs.
Maximum spawning occurs in spring although individuals may spawn over a protracted period. Gonad weight is maximal in February / March in English Channel (Comely & Ansell 1989) but decreases during spawning in spring and then increases again through summer and winter until the next spawning; there is no resting phase. Spawning occurs just before the seasonal rise in temperature in temperate zones but is probably not triggered by rising temperature (Bishop 1985). Spawning may coincide with spring phytoplankton bloom although there is no evidence to substantiate this suggestion.
Comely & Ansell (1989) demonstrated differences in reproductive condition between sites and habitats. Emson & Moore (1998) noted that gonad size varied with diet in the Isle of Cumbrae, Scotland; specimens feeding on barnacles had a higher gonad index than those feeding within the kelp forest.
Planktonic development is complex and takes between 45 -60 days in captivity (MacBride 1914). Development includes a blastula, gastrula and a characteristic, four armed echinopluteus stage that forms an important component of the zooplankton. The development of Echinus esculentus is described in detail by MacBride (1903, 1914). Photographs of the echinopluteus and fully formed juveniles are given by Todd et al. (1996).
Recruitment is sporadic or variable depending on locality, e.g. Millport populations showed annual recruitment, whereas few recruits were found in Plymouth populations during Nichols studies between 1980-1981 (Nichols 1984). Bishop & Earll (1984) suggested that the population of Echinus esculentus at St Abbs had a high density and recruited regularly whereas the Skomer population was sparse, ageing and had probably not successfully recruited larvae in the previous 6 years.
Settlement is thought to occur in autumn and winter (Comely & Ansell, 1988). Newly settled juveniles have an ambital diameter of 0.68 - 0.95mm (Nichols 1984).
Comely & Ansell (1988) noted that the largest number of Echinus esculentus occurred below the kelp forest. Similarly, Lang & Mann (1978) noted that young Strongylocentrotus droebachiensis recruited in urchin barrens, suggesting that urchin recruitment is improved in the absence of kelp, presumably due to differences in microclimate, the absence of suspension feeders and other predators associated with kelp beds.

Reproduction References

Lawrence, 1975, MacBride, 1903, Hyman, 1955, Gage, 1992(a), Gage, 1992(b), Nichols, 1979, Nichols, 1969, Emson & Moore, 1998, MacBride, 1914, Nichols, 1984, Lang & Mann, 1978, Bishop, 1985, Boolootian, 1966, Bishop & Earll, 1984, Todd et al., 1996, Julie Bremner, unpub data, Rees & Dare, 1993,