|Researched by||Dr Harvey Tyler-Walters||Refereed by||Prof. David Nichols|
|Other common names||-||Synonyms||-|
A large globular sea urchin, up to 15 -16 cm in diameter at 7-8 years of age, although the largest diameter recorded was 17.6 cm. The test may be relatively flat in shallow water but taller in deep water. Test pinkish-red but occasionally yellow, green or purple. Spines closely cover the test and are reddish, usually with violet points and white bosses. Primary and secondary spines and their bosses are similar in size, except in small specimens in which the primaries are conspicuous. Ambulacral plates bear 3 pairs of pores. Primary tubercles (bosses) found on every second or third ambulacral plate. All coronal plates bear pedicellariae (modified spines). Plates covering the mouth membrane bear small, club shaped spines as well as pedicellariae. Globeriferous pedicellariae bear 1 lateral tooth below the terminal tooth. The polychaete Flabelligera affinis may be found amongst its spines.
The genus Echinus is derived from the Greek 'echinos' meaning 'a hedgehog'. An omnivorous grazer feeding on seaweeds (e.g. Laminaria spp. sporelings), Bryozoa, barnacles and other encrusting invertebrates. Size range varies depending on age and locality, e.g. c. 4 cm at 1 year, 4-7 cm at 2 years, 7 -9 cm at 3 years and 9-11 cm at 4 years. This species may hybridize with Echinus acutus if sympatric.
|Phylum||Echinodermata||Starfish, brittlestars, sea urchins & sea cucumbers|
|Class||Echinoidea||Sea urchins, heart urchins and sand dollars|
|Typical abundance||High density|
|Male size range|
|Male size at maturity||circa 4cm|
|Female size range||circa 4cm|
|Female size at maturity|
|Growth rate||See text|
|Characteristic feeding method||Active suspension feeder|
|Typically feeds on||Recorded feeding on; worms, barnacles (e.g. Balanus spp.), hydroids, tunicates, bryozoans (e.g. Membranipora spp.), macroalgae (e.g. Laminaria spp.), bottom material and detritus (reviewed by Lawrence 1975).|
Turbellarian parasites Syndesmis rubida sp. nov. and Syndesmis albida sp. nov. (Kozloff & Westervelt 1990), the parasitic nematode Echinomermella grayi and external parasitic amphipod Euonyx chelatus (Comely & Ansell 1988)
|Is the species harmful?||No|
Growth rates are variable depending on time of larval settlement, food availability, water temperature and age. Growth rates vary with locality although there is evidence to suggest that largest specimens are found in the south west (Nichols 1979). Growth rates based on growth lines in skeletal plates are probably underestimates (Gage 1992a & b). In the UK population growth is continuous in the first year after metamorphosis and considerably faster than adults in their 2nd year. In adults maximal growth occurs in a few months in spring and early summer but mature adults are slow growing. Comely & Ansell (1988) recorded 28 invertebrate species associated with Echinus esculentus from the west cost of Scotland near Oban. These included the parasites Echinomermella grayi and Euonyx chelatus mentioned above and in additional; 4 species of commensal polychaetes, a copepod and 10 amphipod species. The polychaete Adyte assimilis and the copepod Pseudoanthessius liber were regular commensals amongst the spines. Hyman (1955) states that Echinus esculentus is often infested with parasitic copepods e.g. Asterocheres echinola.
|Physiographic preferences||Open coast, Strait / sound, Sea loch / Sea lough, Ria / Voe, Enclosed coast / Embayment|
|Biological zone preferences||Lower circalittoral, Lower infralittoral, Sublittoral fringe, Upper circalittoral, Upper infralittoral|
|Substratum / habitat preferences||Artificial (man-made), Bedrock, Caves, Crevices / fissures, Large to very large boulders, Overhangs, Rockpools, Small boulders, Under boulders|
|Tidal strength preferences||Moderately Strong 1 to 3 knots (0.5-1.5 m/sec.)|
|Wave exposure preferences||Exposed, Moderately exposed, Sheltered|
|Salinity preferences||Full (30-40 psu)|
|Depth range||Low water to circa 40m|
|Other preferences||At very wave exposed sites, Echinus esculentus is unlikely to be present in shallow depths because of displacement by wave action. However, presence of this species as shallow as 15m depth at Rockall suggests an ability to withstand severe wave action (Keith Hiscock pers. comm.).|
|Migration Pattern||Non-migratory / resident|
|Reproductive type||Gonochoristic (dioecious)|
|Reproductive frequency||Annual episodic|
|Fecundity (number of eggs)||>1,000,000|
|Generation time||1-2 years|
|Age at maturity||1-3 years|
|Season||February - June|
|Life span||5-10 years|
|Duration of larval stage||1-2 months|
|Larval dispersal potential||Greater than 10 km|
|Larval settlement period|
This MarLIN sensitivity assessment has been superseded by the MarESA approach to sensitivity assessment. MarLIN assessments used an approach that has now been modified to reflect the most recent conservation imperatives and terminology and are due to be updated by 2016/17.
|Sea urchins are slow moving and unlikely to escape removal of their substratum. However, a proportion of the population would probably survive removal of algal substratum. Investigation of the effects of algal destruction on populations of Strongylocentrotus droebachiensis suggested that populations of urchins do not migrate away from or starve in areas devoid of kelp, presumably because they are able to feed on alternative prey. Areas lacking algae were dominated by young urchins up to 4 years after removal of the kelp suggesting that kelp barrens afforded improved recruitment (Lang & Mann 1978), presumably because of the lack of suspension feeding organisms associated with kelp beds. The presence of coralline algae in 'urchin barrens' may encourage larval metamorphosis in echinoids (Pearce & Scheibling 1990).|
|The adults are slow moving and unlikely to be able to avoid smothering. A 5 cm layer of sediment is likely to affect smaller specimens more than large specimens. Smothered individuals are unlikely to be able to move through sediment. However, individuals are unlikely to starve within a month. Comely & Ansell (1988) recorded large Echinus esculentus from kelp beds on the west coast of Scotland in which the substratum was seasonally covered with "high levels" of silt. This suggests that Echinus esculentus is unlikely to be killed by smothering, however, smaller specimens and juveniles may be more intolerant. A layer of sediment may interfere with larval settlement. Lewis & Nichols (1979) found that adults were able to colonize an artificial reef in small numbers within 3 months and the population steadily grew over the following year. Recruitment is sporadic or annual depending on locality and factors affecting larval pre-settlement and post-settlement survival.|
|Low||Very high||Very Low||Low|
|Moore (1977) suggested that Echinus esculentus was unaffected by turbid conditions. Similarly, Comely & Ansell (1988) recorded this species in the presence of suspended material up to 5-6 mg/l. Echinoderm pedicellariae keep the test clear of settling larvae, spores and presumably sediment particles. Echinus esculentus is known to ingest sediment (Comely & Ansell, 1988) possibly to extract microalgae. Therefore, an increase in siltation may not kill this species but is likely to interfere with feeding and additional scour may reduce larval settlement. The increased turbidity associated with siltation is likely to adversely affect its main food species, the kelps, benthic macroalgae and epi-fauna.|
|The majority of Echinus esculentus are subtidal although they occur occasionally in the lower intertidal. They are slow moving and unlikely to be able to return to water quickly. If exposed to desiccation it is likely to be intolerant of exposure to air and sunshine for 1 hour.|
|Low||Very high||Very Low||Very low|
|The majority of Echinus esculentus are subtidal although they occur occasionally in the lower intertidal. An increase in emergence will depress the height up the shore that this species can occur.|
|Low||Very high||Very Low||Low|
|Echinus esculentus occurred in kelp beds on the west coast of Scotland in currents of about 1 knot. Outside the beds specimens were occasionally seen being rolled by the current (Comely & Ansell 1988), which may have been up to 2.6 knots. Urchins are removed from the stipe of kelps by wave and current action. Echinus esculentus are also displaced by storm action. However, urchins were found to feed normally only when provided with 'good' water flow (Boolootian 1966). After disturbance Echinus esculentus migrates up the shore, an adaptation to being washed to deeper water by wave action (Lewis & Nichols 1979b). Therefore, increased water flow may remove the population from the affected area; probably to deeper water although individuals would probably not be killed in the process and could recolonize the area if the factor returned to its pre-impact condition.|
|Echinus esculentus occurred at temperatures between 0 - 18 °C in the Limfjord, Denmark (Ursin 1960). Bishop (1985) noted that gametogenesis proceeded at temperatures between 11 - 19 °C although continued exposure to 19 °C destroyed synchronicity of gametogenesis between individuals. Embryos and larvae developed abnormally after up to 24hr at 15 °C (Tyler & Young 1998) but normally at the other temperatures tested (4, 7 and 11 °C at 1 atmosphere). Tyler & Young (1998) concluded that embryos and larvae were more tolerant of depth and temperature than adults. Bishop (1985) suggested that this species cannot tolerate high temperatures for prolonged periods due to increased respiration rate and resultant metabolic stress. Therefore, Echinus esculentus is likely to exhibit a 'low' intolerance to chronic long term temperature change but would probably be more intolerant of sudden or short term acute change (e.g. 5 °C for 3 days) in temperature.|
|Low||Very high||Very Low||Low|
|Moore (1977) suggested that Echinus esculentus was unaffected by turbid conditions. However, increased turbidity and resultant reduced light penetration is likely to affect macroalgal populations e.g. kelps, which are a preferred food species for Echinus esculentus. However, it can feed on alternative prey, detritus or dissolved organic material (Lawrence, 1975, Comely & Ansell, 1988).|
|Low||Very high||Very Low||Low|
|Wave exposure prevents urchins invading the sub-littoral fringe in exposed sites. Higher levels of wave action are likely to depress the upper extent of Echinus esculentus populations. Decreased wave action is likely to allow the local urchin population to migrate into shallow water depths with resultant impact of algal communities. Lewis & Nichols (1979b) reported that Echinus esculentus migrated to shallow water after disturbance, an adaptation to being washed to deeper water by wave action. However, in the most wave exposed location in the British Isles at Rockall, Echinus esculentus occurred in significant numbers as shallow as 15m below low water level (Keith Hiscock pers. comm.).|
|Tolerant||Not relevant||Not sensitive||Not relevant|
|No evidence of sound or vibration reception in echinoids was found.|
|Bright light and shading elicit well studied reactions in echinoderms. In echinoids shading results in the 'shadow reaction' in which the pedicellariae and spines are pointed in the direction of the shade in a defensive reaction. Echinoids move away from bright light and seek out crevices and / or cover themselves with debris such as shells and drift algae, the 'covering reaction' (see Boolootian (1966) for discussion). Movement of boats is unlikely to be noticed, especially under a kelp canopy in which light may penetrate intermittently with passing currents. If echinoids such as Echinus esculentus react to the approach of divers and snorkelers at closer proximity, the reaction is likely to be short lived and insignificant.|
|Species with fragile tests, such as Echinus esculentus and Echinocardium cordatum were reported to suffer badly as a result of impact with passing scallop or queen scallop dredges (Bradshaw et al., 2000; Hall-Spencer & Moore, 2000a). Adults can repair non-lethal damage to the test and spines can be re-grown but most dredge impact is likely to be lethal. Therefore, physical abrasion due to a passing anchor or dredge is likely to kill a proportion of the population and an intolerance of intermediate has been recorded. Lewis & Nichols (1979) found that adults were able to colonize an artificial reef in small numbers within 3 months and the population steadily grew over the following year. Recoverability is probably high. However, recruitment is sporadic or annual depending on locality and factors affecting larval pre-settlement and post-settlement survival.|
|Low||Very high||Very Low||Moderate|
|Echinus esculentus is probably regularly displaced to deeper water by storms. Displaced specimens are able to move up the shore after displacement (Lewis & Nichols 1979b).|
|Echinus esculentus is subtidal and unlikely to be directly exposed to oil spills, except from dissolved oil or oil adsorbed to particulates. However, large numbers of dead Echinus esculentus were found between 5.5 and 14.5 m in the vicinity of Sennen, presumably due to a combination of wave exposure and heavy spraying of dispersants in that area (Smith 1968). Smith (1968) also demonstrated that 0.5 -1ppm of the detergent BP1002 resulted in developmental abnormalities in echinopluteus larvae of Echinus esculentus. Echinus esculentus populations in the vicinity of an oil terminal in A Coruna Bay, Spain, showed developmental abnormalities in the skeleton. The tissues contained high levels of aliphatic hydrocarbons, naphthalenes, pesticides and heavy metals (Zn, Hg, Cd, Pb, and Cu) (Gomez & Miguez-Rodriguez 1999). However, the observed effects may have been due to a single contaminant or synergistic effects of all present. Sea-urchins, especially the eggs and larvae are used for toxicity testing and environmental monitoring (reviewed by Dinnel et al. 1988). It is likely therefore that Echinus esculentus and especially its larvae are highly intolerant of synthetic contaminants.|
|Little is known about the effects of heavy metals on echinoderms. Bryan (1984) reported that early work had shown that echinoderm larvae were intolerant of heavy metals, e.g. the intolerance of larvae of Paracentrotus lividus to copper (Cu) had been used to develop a water quality assessment. Kinne (1984) reported developmental disturbances in Echinus esculentus exposed to waters containing 25 µg / l of copper (Cu). Sea-urchins, especially the eggs and larvae, are used for toxicity testing and environmental monitoring (reviewed by Dinnel et al. 1988). Taken together with the findings of Gomez & Miguez-Rodriguez (1999) above it is likely that Echinus esculentus is intolerant of heavy metal contamination.|
|Echinus esculentus is subtidal and unlikely to be directly exposed to oil spills, except from dissolved oil or oil adsorbed to particulates. However, large numbers of dead Echinus esculentus were found between 5.5 and 14.5 m in the vicinity of Sennen, presumably due to a combination of wave exposure and heavy spraying of dispersants in that area (Smith 1968). Smith (1968) also demonstrated that 0.5 -1ppm of the detergent BP1002 resulted in developmental abnormalities in its echinopluteus larvae. Echinus esculentus populations in the vicinity of an oil terminal in A Coruna Bay, Spain, showed developmental abnormalities in the skeleton. The tissues contained high levels of aliphatic hydrocarbons, naphthalenes, pesticides and heavy metals (Zn, Hg, Cd, Pb, and Cu) (Gomez & Miguez-Rodriguez 1999). However, the observed effects may have been due to a single contaminant or synergistic effects of all present. Sea-urchins, especially the eggs and larvae, are used for toxicity testing and environmental monitoring (reviewed by Dinnel et al. 1988). It is likely therefore that Echinus esculentus and especially its larvae are highly intolerant of hydrocarbon contamination.|
|No information||No information||No information||Not relevant|
|Tolerant*||Not relevant||Not sensitive*||Very low|
|The addition of nutrients may encourage the growth of ephemeral and epiphytic algae and therefore increase the food available to sea-urchin populations. Lawrence (1975) reported that sea urchins had persisted over 13 years on barren grounds near sewage outfalls, presumably feeding on dissolved organic material, detritus, plankton and microalgae, although individuals died at an early age. The ability to absorb dissolved organic material was suggested by Comely & Ansell (1988).|
|Echinoderms are generally unable to tolerate low salinity (stenohaline) and possess no osmoregulatory organ (Boolootian 1966). At low salinity urchins gain weight, and the epidermis loses its pigment as patches are destroyed; prolonged exposure is fatal. The coelomic fluid of Echinus esculentus is isotonic with seawater (Stickle & Diehl 1987). There is some evidence for intracellular regulation of osmotic pressure due to increased amino acid concentrations. Populations in the sublittoral fringe probably encounter reduced salinity due to low water and fresh water runoff or heavy rain and may tolerate low salinity for short periods. However, echinoderm larvae have a narrow range of salinity tolerance and develop abnormally and die if exposed to reduced or increased salinity.|
|Under hypoxic conditions echinoderms become less mobile and stop feeding. Death of a bloom of the phytoplankton Gyrodinium aureolum in Mounts Bay, Penzance in 1978 produced a layer of brown slime on the sea bottom. This resulted in the death of fish and invertebrates, including Echinus esculentus, presumably due to anoxia caused by the decay of the dead dinoflagellates (Griffiths et al. 1979).|
|Echinus esculentus is susceptible to 'Bald-sea-urchin disease', which causes lesions, loss of spines, tube feet, pedicellariae, destruction of the upper layer of skeletal tissue and death. It is thought to be caused by the bacteria Vibrio anguillarum and Aeromonas salmonicida. Bald sea-urchin disease was recorded from Echinus esculentus on the Brittany Coast. Although associated with mass mortalites of Strongylocentrotus franciscanus in California and Paracentrotus lividus in the French Mediterranean it is not known if the disease induces mass mortality (Bower 1996). However, no evidence of mass mortalities of Echinus esculentus associated with disease have been recorded in Britain and Ireland.|
|Not relevant||Not relevant||Not relevant||Not relevant|
|No alien or non-native species is known to compete with Echinus esculentus.|
|Collecting of Echinus esculentus for the curio trade was studied by Nichols (1984). He concluded that the majority of divers collected only large specimens that are seen quickly and often missed individuals covered by seaweed or under rocks, especially if small. As a result, a significant proportion of the population remains. He suggested that exploited populations should not be allowed to fall below 0.2 individuals per square metre.|
|Populations of Strongylocentrotus droebachiensis do not migrate away after destroying an area of kelp, although individuals growth rate and gonad production decreases. Over the next 3-4 years the population became dominated by younger urchins, suggesting that recruitment (larval settlement and post-settlement survival) was improved within the 'urchin barren' (Lang & Mann, 1979). Since Echinus esculentus is an omnivore it is likely that kelp harvesting will have little effect on the population and may improve recruitment in the short term.|
Species with fragile tests, such as Echinus esculentus and Echinocardium cordatum were reported to suffer badly as a result of impact with passing scallop or queen scallop dredges (Bradshaw et al., 2000; Hall-Spencer & Moore, 2000a). Kaiser et al. (2000) reported that Echinus esculentus were less abundant in areas subject to high trawling disturbance in the Irish Sea. Adults can repair non-lethal damage to the test and spines can be re-grown but most dredge impact is likely to be lethal. Therefore, Echinus esculentus is likely to be of intermediate intolerance to the effects of fishing activities for other species.
|IUCN Red List||Near Threatened (NT)|
|National (GB) importance||Not rare/scarce||Global red list (IUCN) category||Near Threatened (NT)|
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This review can be cited as:
Last Updated: 29/04/2008