BIOTIC

BIOTIC Species Information for Idotea pelagica

Researched by

Andrew Hosie

Data supplied by

MarLIN

Refereed by

This information is not refereed.

Taxonomy

Scientific name

Idotea pelagica

Common name

An isopod

MCS Code

S942

Recent Synonyms

Phylum

Arthropoda

Subphylum

Crustacea

Superclass

Class

Malacostraca

Subclass

Eumalacostraca

Order

Isopoda

Suborder

Family

Idoteidae

Genus

Idotea

Species

pelagica

Subspecies

Additional Information

Taxonomy References

Naylor, 1972, Hayward & Ryland, 1995b, Picton & Howson, 1997,

General Biology

Growth form

Feeding method

Omnivore

Mobility/Movement

Swimmer
Crawler

Environmental position

Epifaunal
Epibenthic
Epiphytic
Epizoic

Typical food types

Omnivorous; fucoid algae, associated epiphytes, barnacle cirri.

Habit

Free living

Bioturbator

Not relevant

Flexibility

Low (10-45 degrees)

Fragility

Intermediate

Size

Small(1-2cm)

Height

Not researched

Growth Rate

Not researched

Adult dispersal potential

Insufficient information

Dependency

Independent

Sociability

Solitary

Host for

Parasitised by Clypeoniscus hanseni (Isopoda, Cryptoniscoidea).

Toxic/Poisonous?

General Biology Additional Information

Biology References

Naylor, 1972, Naylor, 1955, Leifsson, 1999, Kroer, 1986, Healy & O'Neill, 1984, Sheader, 1977,

Distribution and Habitat

Distribution in Britain & Ireland

Found on all British and Irish coasts.

Global distribution

Found from Iceland, Norway south to Spanish coast of the Bay of Biscay, not found in the Baltic.

Biogeographic range

Arctic-boreal to temperate.

Depth range

0-10 m

Migratory

Non-migratory / Resident

Distribution Additional Information

Substratum preferences

Algae

Physiographic preferences

Open coast

Biological zone

Upper Eulittoral
Mid Eulittoral
Lower Eulittoral
Sublittoral Fringe
Upper Infralittoral
Lower Infralittoral
Upper Circalittoral

Wave exposure

Very Exposed
Exposed

Tidal stream strength/Water flow

Insufficient information

Salinity

Full (30-40 psu)

Habitat Preferences Additional Information

There are a total of 8 members of Idotea in British waters which can be distinguished using the keys provided in Naylor (1972) and Hayward & Ryland (1995b). The various species are not typically sympatric, but are ecologically segregated. For example, Idotea pelagica is found in the lower intertidal and shallow subtidal on exposed rocky reefs and is replaced in less exposed areas by I. granulosa which in turn is replaced by I. chelipes on sheltered, estuarine shores (Naylor, 1955).

Distribution References

Naylor, 1972, Hayward & Ryland, 1995b, Bruce et al., 1963, MBA, 1957, Picton & Howson, 1997, NBN, 2002, Naylor, 1955, Leifsson, 1999, Kroer, 1986, Healy & O'Neill, 1984, Sheader, 1977,

Reproduction/Life History

Reproductive type

Gonochoristic

Developmental mechanism

Direct Development
Brooding

Reproductive Season

See additional information

Reproductive Location

Sediment surface

Reproductive frequency

Annual protracted

Regeneration potential

Yes

Life span

1-2 years

Age at reproductive maturity

<1 year

Generation time

<1 year

Fecundity

10-100

Egg/propagule size

Insufficient information

Fertilization type

Internal

Larvae/Juveniles
Larval/Juvenile dispersal potential	Insufficient information	Larval settlement period	See additional information
Duration of larval stage	See additional information

Reproduction Preferences Additional Information

Reproductive season

The reproductive season of Idotea pelagica is closely linked to temperature (Leifsson, 1999). Reproductive effort is at its greatest during periods when the sea water temperature is between 5 and 12 °C (Sheader, 1977; Healy & O’Neill, 1984; Leifsson, 1999). While ovigerous females are found all year round in southern Irish coasts, the highest proportion of ovigerous females are found between December and August (Healy & O’Neill, 1984), while on the Northeast coast of England ovigerous females were found only between April and August (Sheader, 1977). Icelandic populations have their reproductive period further reduced to May to July (Leifsson, 1999). In the more southern extent of its range, the reproductive season of Idotea pelagica would be expected to shift further towards winter.

Fecundity

Females brood up to 80 eggs for 6-8 weeks (Leifsson, 1999), as with most isopods there is no larval stage and the juveniles appear as the adults, but with 6 pairs of pereopods not 7. Once the eggs hatch, females may then moult and produce a second brood (Healy & O'Neill, 1984).

Reproduction References

Leifsson, 1999, Healy & O'Neill, 1984, Sheader, 1977,