MarLIN

information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

Lagoon sea slug (Tenellia adspersa)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.

Summary

Description

A tiny nudibranch with few finger-like protrusions, arranged in groups of two or three along each side of the body. The pale brown body is marked with tiny black spots as are the protrusions. It grows up to 8 mm in length.

Recorded distribution in Britain and Ireland

The few British records are from the Firth of Forth, Scotland, near St Osyth, Essex, the Fleet, Dorset, the Bristol Channel, off Pembrokeshire and Liverpool Bay.

Global distribution

Recorded from the eastern and western North Atlantic, Baltic, Mediterranean Sea, Black Sea, Azov Sea, Caspian Sea, Japan, Pacific coast of USA, Brazil

Habitat

Found intertidally and in the shallow sublittoral. A euryhaline species often in harbours, estuaries and canals.

Depth range

-

Identifying features

  • Few cerata arranged in groups of two or three along each side of the body.
  • Body pale brown and marked with tiny black spots as are the cerata.
  • Digestive gland is pale orange in colour.
  • Oral tentacles are small and directed laterally.

Additional information

No text entered

Listed by

Further information sources

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Biology review

Taxonomy

PhylumMollusca
ClassGastropoda
OrderNudibranchia
FamilyTrinchesiidae
GenusTenellia
Authority(Nordmann, 1845)
Recent SynonymsTenellia pallida (Nordmann, 1845)Embletonia pallida (Nordmann, 1845)

Biology

Typical abundanceModerate density
Male size rangeUp to 8mm
Male size at maturity3.60mm
Female size range3.60mm
Female size at maturity
Growth formLanceolate
Growth rateData deficient
Body flexibility
Mobility
Characteristic feeding methodNo information, Predator
Diet/food sourceNo information
Typically feeds onHydroids, especially %Cordylophora caspia%, Laomeda spp. and %Protohydra leuckarti%
Sociability
Environmental positionEpifaunal
Dependency-
Supports-
Is the species harmful?Data deficient

Biology information

Tenellia adspersa can rapidly devour hydroid colonies, exhausting its own food supply. It has been suggested that the developmental plasticity and rapid growth of this species enables it to disperse to new locations to find new food.

Habitat preferences

Physiographic preferencesEstuary, Isolated saline water (Lagoon), Enclosed coast / Embayment
Biological zone preferencesLower eulittoral, Sublittoral fringe, Upper infralittoral
Substratum / habitat preferencesMacroalgae, Cobbles, Pebbles, Small boulders
Tidal strength preferencesModerately Strong 1 to 3 knots (0.5-1.5 m/sec.), Strong 3 to 6 knots (1.5-3 m/sec.), Weak < 1 knot (<0.5 m/sec.)
Wave exposure preferencesSheltered, Very sheltered
Salinity preferencesLow (<18 psu), Variable (18-40 psu)
Depth range
Other preferencesNo text entered
Migration PatternNon-migratory / resident

Habitat Information

Recorded at depths from 1 to 34 m. The species has been observed to survive and breed in salinities from 50 psu to 5.3 psu. The ranges and ecological features of the nudibranch are very similar to the hydroid Cordylophora caspia and they co-exist everywhere, which suggests some connection. The wide geographic distribution of Tenellia adspersa is probably due to passive transportation of adults and egg masses by Cordylophora colonies on ships.

Life history

Adult characteristics

Reproductive typeGonochoristic (dioecious)
Reproductive frequency Annual protracted
Fecundity (number of eggs)11-100
Generation time<1 year
Age at maturity19 to 20 days
SeasonInsufficient information
Life span<1 year

Larval characteristics

Larval/propagule type-
Larval/juvenile development Direct development
Duration of larval stageNo information
Larval dispersal potential 100 -1000 m
Larval settlement periodInsufficient information

Life history information

Tenellia adspersa has a subannual lifecycle with a short generation time of as little as 20 days when reared at 20 degrees C and 30 ppt on the hydroid Cordylophora lacustris. The animals may spawn 3 to 5 times a day with 25 to 50 eggs per spawn (Chester, 1996). The spawn consists of a short, curved, lozenge-shaped mass. The period from spawning to hatching lasts 4-5 days. The method of development varies with the environmental conditions. Metamorphosis normally takes place within the egg capsule, hatching as a juvenile. In animals that have been starved a switch to pelagic non-feeding or planktotrophic development has been observed.

Sensitivity reviewHow is sensitivity assessed?

Physical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
High Very low / none Very High Low
The species lives on hydroids attached to rocks, algae or artificial substrates. The loss of the substrate would cause removal of the species and recovery would be very low due to the limited distribution of the host species.
High Very low / none Very High Low
The hydroids on which Tenellia adspersa lives may be killed by smothering, so removing the species food source. Recovery would be low due to the limited distribution of the Tenellia adspersa.
Low High Low Low
The species is probably able to tolerate siltation as it occurs in estuaries and lagoons where siltation naturally occurs. Recovery from any damage could be rapid due to the fast growth and reproductive rates of the species.
No information
High Very low / none Very High Low
The low shore position and soft-bodied nature of this species suggests that it is unlikely to tolerate desiccation. Where the species is exposed to desiccation, individuals are likely to be present deeper at the site, so providing a source for recolonization. Where unaffected individuals are not present recovery would be low due to the species limited distribution.
High Very High Low
The low shore position and soft-bodied nature of this species suggests that it is unlikely to tolerate emersion as it would suffer desiccation. Where the species is exposed to emersion, individuals are likely to be present deeper at the site, so providing a source for recolonization. Where unaffected individuals are not present recovery would be low due to the species limited distribution.
No information
Tolerant Not relevant Not sensitive Moderate
The species is normally found at sites of slow water current, but it has been observed to withstand rapid water flow (0.8-2.4m/sec.) as evidenced by animals occupying the lattices of pipe lines.
No information
Low Moderate Low Low
Tenellia adspersa can live under a wide range of water temperatures since it occurs in lagoons which undergo great seasonal temperature variation and it occupies a wide geographic range, from the Lofoten Islands to the Mediterranean.
No information
Tolerant Not relevant Not sensitive Low
Neither the species or the hydroids on which it lives are dependant on light availability, so it would not be affected by a change in turbidity.
No information
High Low High Very low
The species is largely known from wave sheltered locations, which suggests an inability to tolerate exposed conditions. Recovery would be low due to the limited distribution of the species.
No information
Tolerant Not relevant Not sensitive Not relevant
The species probably has very limited capacity for noise perception
Tolerant Not relevant Not sensitive Not relevant
The species probably has very limited capacity for visual perception.
High Moderate Moderate Low
The species occurs in the surface hydroid turf and it is soft-bodied so would be easily damaged upon impact. In addition, a passing dredge is likely to damage its substratum (see substratum loss above). Therefore, an intolerance of high has been recorded.
Low High Low Moderate
Tenellia adspersa would not be affected by displacement, indeed the species has formed colonies in distant locations by transport on ships.

Chemical pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information Not relevant No information Not relevant
Insufficient
information
Heavy metal contamination
No information Not relevant No information Not relevant
Insufficient
information
Hydrocarbon contamination
No information Not relevant No information Not relevant
Insufficient
information
Radionuclide contamination
No information Not relevant No information Not relevant
Insufficient
information
Changes in nutrient levels
No information Not relevant No information Not relevant
Insufficient
information
Low High Low High
The species can tolerate a wide range of salinities and will reproduce in salinities of 3 psu to 40 psu (Roginskaya, 1970).
No information
No information Not relevant No information Not relevant
Insufficient
information

Biological pressures

 IntoleranceRecoverabilitySensitivityEvidence/Confidence
No information Not relevant No information Not relevant
Insufficient
information
No information None No information Not relevant
Insufficient
information
No information Not relevant No information Not relevant
Insufficient
information
No information Not relevant No information Not relevant
Insufficient
information

Additional information

Importance review

Policy/legislation

Wildlife & Countryside ActSchedule 5, section 9
UK Biodiversity Action Plan Priority
Species of principal importance (England)
Species of principal importance (Wales)
Features of Conservation Importance (England & Wales)

Status

Non-native

Importance information

-none-

Bibliography

  1. Anonymous, 1999s. Saline lagoons. Habitat Action Plan. In UK Biodiversity Group. Tranche 2 Action Plans. English Nature for the UK Biodiversity Group, Peterborough., English Nature for the UK Biodiversity Group, Peterborough.

  2. Antsulevich, A.Ye. & Starobogatov, Ya.I., 1991. First Record of a Nudibranch Mollusk (Tritoniformes) in the Caspian Sea. Hydrobiological Journal, 27, 71-74.

  3. Chester, C.M., 1996. The effect of adult nutrition on the reproduction and development of Tenellia adspersa (Nordmann, 1845). Journal of Experimental Marine Biology and Ecology, 198, 113-130.

  4. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  5. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  6. Picton, B. E. & Morrow, C.C., 1994. A Field Guide to the Nudibranchs of the British Isles. London: Immel Publishing Ltd.

  7. Roginskaya, I.S., 1970. Tenellia adspersa, a nudibranch new to the Azov Sea with notes on its taxonomy and ecology. Malacological Review, 3, 167-174.

Citation

This review can be cited as:

White, N. 2008. Tenellia adspersa Lagoon sea slug. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. Available from: http://www.marlin.ac.uk/species/detail/1156

Last Updated: 19/08/2008