Lagoon sea slug (Tenellia adspersa)

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

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

Biology review

Taxonomy

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

Biology

ParameterData
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

ParameterData
Physiographic preferencesEstuary, Isolated saline water (Lagoon), Enclosed coast or 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 or 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

ParameterData
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

ParameterData
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

Use / to open/close text displayed

 IntoleranceRecoverabilitySensitivityEvidence / Confidence
Substratum loss [Show more]

Substratum loss

Benchmark. All of the substratum occupied by the species or biotope under consideration is removed. A single event is assumed for sensitivity assessment. Once the activity or event has stopped (or between regular events) suitable substratum remains or is deposited. Species or community recovery assumes that the substratum within the habitat preferences of the original species or community is present. Further details

Evidence

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
Smothering [Show more]

Smothering

Benchmark. All of the population of a species or an area of a biotope is smothered by sediment to a depth of 5 cm above the substratum for one month. Impermeable materials, such as concrete, oil, or tar, are likely to have a greater effect. Further details.

Evidence

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.
High Very low / none Very High Low
Increase in suspended sediment [Show more]

Increase in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

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.
Low High Low Low
Decrease in suspended sediment [Show more]

Decrease in suspended sediment

Benchmark. An arbitrary short-term, acute change in background suspended sediment concentration e.g., a change of 100 mg/l for one month. The resultant light attenuation effects are addressed under turbidity, and the effects of rapid settling out of suspended sediment are addressed under smothering. Further details

Evidence

No information
Desiccation [Show more]

Desiccation

  1. A normally subtidal, demersal or pelagic species including intertidal migratory or under-boulder species is continuously exposed to air and sunshine for one hour.
  2. A normally intertidal species or community is exposed to a change in desiccation equivalent to a change in position of one vertical biological zone on the shore, e.g., from upper eulittoral to the mid eulittoral or from sublittoral fringe to lower eulittoral for a period of one year. Further details.

Evidence

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 low / none Very High Low
Increase in emergence regime [Show more]

Increase in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

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.
High Very High Low
Decrease in emergence regime [Show more]

Decrease in emergence regime

Benchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details

Evidence

No information
Increase in water flow rate [Show more]

Increase in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

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.
Tolerant Not relevant Not sensitive Moderate
Decrease in water flow rate [Show more]

Decrease in water flow rate

A change of two categories in water flow rate (view glossary) for 1 year, for example, from moderately strong (1-3 knots) to very weak (negligible). Further details

Evidence

No information
Increase in temperature [Show more]

Increase in temperature

  1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
  2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

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.
Low Moderate Low Low
Decrease in temperature [Show more]

Decrease in temperature

  1. A short-term, acute change in temperature; e.g., a 5°C change in the temperature range for three consecutive days. This definition includes ‘short-term’ thermal discharges.
  2. A long-term, chronic change in temperature; e.g. a 2°C change in the temperature range for a year. This definition includes ‘long term’ thermal discharges.

For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details

Evidence

No information
Increase in turbidity [Show more]

Increase in turbidity

  1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
  2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

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.
Tolerant Not relevant Not sensitive Low
Decrease in turbidity [Show more]

Decrease in turbidity

  1. A short-term, acute change; e.g., two categories of the water clarity scale (see glossary) for one month, such as from medium to extreme turbidity.
  2. A long-term, chronic change; e.g., one category of the water clarity scale (see glossary) for one year, such as from low to medium turbidity. Further details

Evidence

No information
Increase in wave exposure [Show more]

Increase in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

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.
High Low High Very low
Decrease in wave exposure [Show more]

Decrease in wave exposure

A change of two ranks on the wave exposure scale (view glossary) e.g., from Exposed to Extremely exposed for a period of one year. Further details

Evidence

No information
Noise [Show more]

Noise

  1. Underwater noise levels e.g., the regular passing of a 30-metre trawler at 100 metres or a working cutter-suction transfer dredge at 100 metres for one month during important feeding or breeding periods.
  2. Atmospheric noise levels e.g., the regular passing of a Boeing 737 passenger jet 300 metres overhead for one month during important feeding or breeding periods. Further details

Evidence

The species probably has very limited capacity for noise perception
Tolerant Not relevant Not sensitive Not relevant
Visual presence [Show more]

Visual presence

Benchmark. The continuous presence for one month of moving objects not naturally found in the marine environment (e.g., boats, machinery, and humans) within the visual envelope of the species or community under consideration. Further details

Evidence

The species probably has very limited capacity for visual perception.
Tolerant Not relevant Not sensitive Not relevant
Abrasion & physical disturbance [Show more]

Abrasion & physical disturbance

Benchmark. Force equivalent to a standard scallop dredge landing on or being dragged across the organism. A single event is assumed for assessment. This factor includes mechanical interference, crushing, physical blows against, or rubbing and erosion of the organism or habitat of interest. Where trampling is relevant, the evidence and trampling intensity will be reported in the rationale. Further details.

Evidence

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.
High Moderate Moderate Low
Displacement [Show more]

Displacement

Benchmark. Removal of the organism from the substratum and displacement from its original position onto a suitable substratum. A single event is assumed for assessment. Further details

Evidence

Tenellia adspersa would not be affected by displacement, indeed the species has formed colonies in distant locations by transport on ships.
Low High Low Moderate

Chemical pressures

Use [show more] / [show less] to open/close text displayed

 IntoleranceRecoverabilitySensitivityEvidence / Confidence
Synthetic compound contamination [Show more]

Synthetic compound contamination

Sensitivity is assessed against the available evidence for the effects of contaminants on the species (or closely related species at low confidence) or community of interest. For example:

  • evidence of mass mortality of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as high sensitivity;
  • evidence of reduced abundance, or extent of a population of the species or community of interest (either short or long term) in response to a contaminant will be ranked as intermediate sensitivity;
  • evidence of sub-lethal effects or reduced reproductive potential of a population of the species or community of interest will be assessed as low sensitivity.

The evidence used is stated in the rationale. Where the assessment can be based on a known activity then this is stated. The tolerance to contaminants of species of interest will be included in the rationale when available; together with relevant supporting material. Further details.

Evidence

Insufficient
information
No information Not relevant No information Not relevant
Heavy metal contamination [Show more]

Heavy metal contamination

Evidence

Insufficient
information
No information Not relevant No information Not relevant
Hydrocarbon contamination [Show more]

Hydrocarbon contamination

Evidence

Insufficient
information
No information Not relevant No information Not relevant
Radionuclide contamination [Show more]

Radionuclide contamination

Evidence

Insufficient
information
No information Not relevant No information Not relevant
Changes in nutrient levels [Show more]

Changes in nutrient levels

Evidence

Insufficient
information
No information Not relevant No information Not relevant
Increase in salinity [Show more]

Increase in salinity

  1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
  2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

The species can tolerate a wide range of salinities and will reproduce in salinities of 3 psu to 40 psu (Roginskaya, 1970).
Low High Low High
Decrease in salinity [Show more]

Decrease in salinity

  1. A short-term, acute change; e.g., a change of two categories from the MNCR salinity scale for one week (view glossary) such as from full to reduced.
  2. A long-term, chronic change; e.g., a change of one category from the MNCR salinity scale for one year (view glossary) such as from reduced to low. Further details.

Evidence

No information
Changes in oxygenation [Show more]

Changes in oxygenation

Benchmark.  Exposure to a dissolved oxygen concentration of 2 mg/l for one week. Further details.

Evidence

Insufficient
information
No information Not relevant No information Not relevant

Biological pressures

Use [show more] / [show less] to open/close text displayed

 IntoleranceRecoverabilitySensitivityEvidence / Confidence
Introduction of microbial pathogens/parasites [Show more]

Introduction of microbial pathogens/parasites

Benchmark. Sensitivity can only be assessed relative to a known, named disease, likely to cause partial loss of a species population or community. Further details.

Evidence

Insufficient
information
No information Not relevant No information Not relevant
Introduction of non-native species [Show more]

Introduction of non-native species

Sensitivity assessed against the likely effect of the introduction of alien or non-native species in Britain or Ireland. Further details.

Evidence

Insufficient
information
No information None No information Not relevant
Extraction of this species [Show more]

Extraction of this species

Benchmark. Extraction removes 50% of the species or community from the area under consideration. Sensitivity will be assessed as 'intermediate'. The habitat remains intact or recovers rapidly. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

Insufficient
information
No information Not relevant No information Not relevant
Extraction of other species [Show more]

Extraction of other species

Benchmark. A species that is a required host or prey for the species under consideration (and assuming that no alternative host exists) or a keystone species in a biotope is removed. Any effects of the extraction process on the habitat itself are addressed under other factors, e.g. displacement, abrasion and physical disturbance, and substratum loss. Further details.

Evidence

Insufficient
information
No information Not relevant No information Not relevant

Additional information

Importance review

Policy/legislation

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

Status

Non-native

ParameterData
Native-
Origin-
Date Arrived-

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.

Datasets

  1. Bristol Regional Environmental Records Centre, 2017. BRERC species records recorded over 15 years ago. Occurrence dataset: https://doi.org/10.15468/h1ln5p accessed via GBIF.org on 2018-09-25.

  2. Conchological Society of Great Britain & Ireland, 2018. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: https://doi.org/10.15468/aurwcz accessed via GBIF.org on 2018-09-25.

  3. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  4. Norfolk Biodiversity Information Service, 2017. NBIS Records to December 2016. Occurrence dataset: https://doi.org/10.15468/jca5lo accessed via GBIF.org on 2018-10-01.

  5. OBIS (Ocean Biodiversity Information System),  2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-06-23

Citation

This review can be cited as:

White, N. 2008. Tenellia adspersa Lagoon sea slug. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 23-06-2024]. Available from: https://www.marlin.ac.uk/species/detail/1156

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Last Updated: 19/08/2008