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
Researched by | Nicola White | Refereed by | Dr Richard S.K. Barnes |
Authority | (Nordmann, 1845) | ||
Other common names | - | Synonyms | Tenellia pallida (Nordmann, 1845), Embletonia pallida (Nordmann, 1845) |
Summary
Description
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, BrazilHabitat
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 enteredListed by
Biology review
Taxonomy
Level | Scientific name | Common name |
---|---|---|
Phylum | Mollusca | Snails, slugs, mussels, cockles, clams & squid |
Class | Gastropoda | Snails, slugs & sea butterflies |
Order | Nudibranchia | Naked gilled, shell-less sea slugs |
Family | Trinchesiidae | |
Genus | Tenellia | |
Authority | (Nordmann, 1845) | |
Recent Synonyms | Tenellia pallida (Nordmann, 1845)Embletonia pallida (Nordmann, 1845) |
Biology
Parameter | Data | ||
---|---|---|---|
Typical abundance | Moderate density | ||
Male size range | Up to 8mm | ||
Male size at maturity | 3.60mm | ||
Female size range | 3.60mm | ||
Female size at maturity | |||
Growth form | Lanceolate | ||
Growth rate | Data deficient | ||
Body flexibility | |||
Mobility | |||
Characteristic feeding method | No information, Predator | ||
Diet/food source | No information | ||
Typically feeds on | Hydroids, especially %Cordylophora caspia%, Laomeda spp. and %Protohydra leuckarti% | ||
Sociability | |||
Environmental position | Epifaunal | ||
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
Parameter | Data |
---|---|
Physiographic preferences | Estuary, Isolated saline water (Lagoon), Enclosed coast or Embayment |
Biological zone preferences | Lower eulittoral, Sublittoral fringe, Upper infralittoral |
Substratum / habitat preferences | Macroalgae, Cobbles, Pebbles, Small boulders |
Tidal strength preferences | Moderately 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 preferences | Sheltered, Very sheltered |
Salinity preferences | Low (<18 psu), Variable (18-40 psu) |
Depth range | |
Other preferences | No text entered |
Migration Pattern | Non-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
Parameter | Data |
---|---|
Reproductive type | Gonochoristic (dioecious) |
Reproductive frequency | Annual protracted |
Fecundity (number of eggs) | 11-100 |
Generation time | <1 year |
Age at maturity | 19 to 20 days |
Season | Insufficient information |
Life span | <1 year |
Larval characteristics
Parameter | Data |
---|---|
Larval/propagule type | - |
Larval/juvenile development | Direct development |
Duration of larval stage | No information |
Larval dispersal potential | 100 -1000 m |
Larval settlement period | Insufficient 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 review
The MarLIN sensitivity assessment approach used below has been superseded by the MarESA (Marine Evidence-based Sensitivity Assessment) approach (see menu). The MarLIN approach was used for assessments from 1999-2010. The MarESA approach reflects the recent conservation imperatives and terminology and is used for sensitivity assessments from 2014 onwards.
Physical pressures
Use / to open/close text displayed
Intolerance | Recoverability | Sensitivity | Evidence / Confidence | |
Substratum loss [Show more]Substratum lossBenchmark. 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 EvidenceThe 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]SmotheringBenchmark. 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. EvidenceThe 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 sedimentBenchmark. 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 EvidenceThe 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 sedimentBenchmark. 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
EvidenceThe 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 regimeBenchmark. A one hour change in the time covered or not covered by the sea for a period of one year. Further details EvidenceThe 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 regimeBenchmark. 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 rateA 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 EvidenceThe 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 rateA 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
For intertidal species or communities, the range of temperatures includes the air temperature regime for that species or community. Further details EvidenceTenellia 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
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
EvidenceNeither 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
Evidence | No information | |||
Increase in wave exposure [Show more]Increase in wave exposureA 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 EvidenceThe 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 exposureA 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
EvidenceThe species probably has very limited capacity for noise perception | Tolerant | Not relevant | Not sensitive | Not relevant |
Visual presence [Show more]Visual presenceBenchmark. 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 EvidenceThe species probably has very limited capacity for visual perception. | Tolerant | Not relevant | Not sensitive | Not relevant |
Abrasion & physical disturbance [Show more]Abrasion & physical disturbanceBenchmark. 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. EvidenceThe 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]DisplacementBenchmark. 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 EvidenceTenellia 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
Intolerance | Recoverability | Sensitivity | Evidence / Confidence | |
Synthetic compound contamination [Show more]Synthetic compound contaminationSensitivity 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:
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. EvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Heavy metal contamination [Show more]Heavy metal contaminationEvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Hydrocarbon contamination [Show more]Hydrocarbon contaminationEvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Radionuclide contamination [Show more]Radionuclide contaminationEvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Changes in nutrient levels [Show more]Changes in nutrient levelsEvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Increase in salinity [Show more]Increase in salinity
EvidenceThe 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
Evidence | No information | |||
Changes in oxygenation [Show more]Changes in oxygenationBenchmark. Exposure to a dissolved oxygen concentration of 2 mg/l for one week. Further details. EvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Biological pressures
Use [show more] / [show less] to open/close text displayed
Intolerance | Recoverability | Sensitivity | Evidence / Confidence | |
Introduction of microbial pathogens/parasites [Show more]Introduction of microbial pathogens/parasitesBenchmark. Sensitivity can only be assessed relative to a known, named disease, likely to cause partial loss of a species population or community. Further details. EvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Introduction of non-native species [Show more]Introduction of non-native speciesSensitivity assessed against the likely effect of the introduction of alien or non-native species in Britain or Ireland. Further details. EvidenceInsufficientinformation | No information | None | No information | Not relevant |
Extraction of this species [Show more]Extraction of this speciesBenchmark. 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. EvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Extraction of other species [Show more]Extraction of other speciesBenchmark. 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. EvidenceInsufficientinformation | No information | Not relevant | No information | Not relevant |
Additional information
Importance review
Policy/legislation
Designation | Support |
---|---|
Wildlife & Countryside Act | Schedule 5, section 9 |
UK Biodiversity Action Plan Priority | Yes |
Species of principal importance (England) | Yes |
Species of principal importance (Wales) | Yes |
Features of Conservation Importance (England & Wales) | Yes |
Status
National (GB) importance | Nationally rare | Global red list (IUCN) category | - |
Non-native
Parameter | Data |
---|---|
Native | - |
Origin | - |
Date Arrived | - |
Importance information
-none-Bibliography
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.
Antsulevich, A.Ye. & Starobogatov, Ya.I., 1991. First Record of a Nudibranch Mollusk (Tritoniformes) in the Caspian Sea. Hydrobiological Journal, 27, 71-74.
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.
Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.
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.]
Picton, B. E. & Morrow, C.C., 1994. A Field Guide to the Nudibranchs of the British Isles. London: Immel Publishing Ltd.
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
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.
Conchological Society of Great Britain & Ireland, 2023. Mollusc (marine) records for Great Britain and Ireland. Occurrence dataset: https://doi.org/10.15468/aurwcz accessed via GBIF.org on 2024-09-27.
NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.
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.
OBIS (Ocean Biodiversity Information System), 2024. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2024-10-09
Citation
This review can be cited as:
Last Updated: 19/08/2008