Nemertesia

A Intermediate genera from the “Other: Cnidaria” group, mostly found in Cobbles

Cobbles

Intermediate

Other: Cnidaria

Genera Characteristics Recorded Traits Possible Values
Size in cm
  • 11-20 cm
  • <1 cm
  • 1-10 cm
  • 11-20 cm
  • >20 cm
Genera Characteristics Recorded Traits Possible Values
Motility (Adult)
  • Sedentary
  • Adult
  • Short Range Mobility
  • Sedentary

“Sedentary”

Motility (Larval)
  • Short Term Planktonic
  • Long Term Planktonic
  • Short Term Planktonic
  • Brooded or Laid Eggs

“Short Term Planktonic”

Lifespan
  • <1 year
  • >10 years
  • 3-10 years
  • 1-2 years
  • <1 year
Maturity
  • >4 years
  • 3-4 years
  • 1-2 years
  • <1 year
Fecundity
  • 1 - 10
  • 10 - 100
  • 100 - 1000
  • 1000 - 10000
  • 10000 - 1 million
  • > 1 million

Image: Nemertesia © John Ryland

Vulnerability

Nemertesia is a hydroid that grows in pinnate or arborescent form on hard substrata (cobbles, boulders, bedrock) on gravelly, maerl or sandy areas and settles preferentially on existing adult masses. It is widely distributed in sheltered environments around the coasts of Britain and Ireland, at depths ranging 10-10,000 m, depending on the species. Nemertesia is a passive suspension feeder and is fed on by a number of sea slugs and sea spiders and offers also support for other epizooties. The colonies are fragile and residential and are likely to be affected by dredging activities.

Recoverability

Nemertesia has a life span of 4-5 months with three generations per year, each featuring a period of growth, reproduction and death. The larvae are lecithotrophic planulae that secrete mucus that may assist in getting caught in the tall branches of other Nemertesia. They settle within the 24 hours and their dispersal cover distances of 0-100 m depending on current speed, turbulence and height of release. Their recovery potential is likely to be moderate.

References

  • Biology

    • Ansín Agís et al., 2001
    • Cornelius, 1995b
    • Gili & Hughes, 1995
    • Hayward & Ryland, 1995b
    • Hughes, 1977
    • Hughes, 1978
  • Taxonomy

    • Ansín Agís et al., 2001
    • Cornelius, 1995b
    • Gibson et al., 2001
    • Hayward & Ryland, 1995b
    • Hayward et al., 1996
    • Howson & Picton, 1997
    • Hughes, 1977
    • Picton & Morrow, 2004
  • Distribution

    • Ansín Agís et al., 2001
    • Cornelius, 1995b
    • Hayward & Ryland, 1995b
    • Hayward et al., 1996
    • Hughes, 1977
    • Jones, 1951
    • NBN, 2002
    • Picton & Costello, 1998
  • Reproduction

    • Ansín Agís et al., 2001
    • Gili & Hughes, 1995
    • Hughes, 1977
    • Hughes, 1979