BIOTIC Species Information for Hediste diversicolor
Researched byGeorgina Budd Data supplied byMarLIN
Refereed byMike Kendall
Distribution and Habitat
Distribution in Britain & IrelandWidespread along all British coasts where suitable habitat and substratum exist.
Global distributionHediste diversicolor is widely distributed throughout north-west Europe on the Baltic Sea, North Sea and along Atlantic coasts to the Mediterranean.
Biogeographic rangeNot researched Depth rangeIntertidal
MigratoryNon-migratory / Resident   
Distribution Additional Information

Distribution & density
Hediste diversicolor is an euryhaline species and can withstand great variances in salinity. Smith (1956) reported that, in the Tamar estuary, England, individuals of this species living at the upstream limit regularly experience salinities less than 0.5 ppt. In marine dominated habitats, Hediste diversicolor behaves as a brackish water animal and is found in the least saline portion of the available ground (Smith, 1956). The distribution of Hediste diversicolor in high salinity areas is likely to be reduced as result of competition in the form of interspecific aggressions (Kristensen, 1988). In a study focussing on the distribution of nereid polychaetes in Danish coastal waters, Kristensen (1988) found that Hediste diversicolor could only maintain high population densities in marginal environments when the fitness of stronger competitors such as %Nereis virens% was reduced.

In estuaries the maximum density of the Hediste diversicolor population normally occurs in the middle regions, with density decreasing both towards the head and mouth of the estuary. Smith (1956), found that the maximum population density of Hediste diversicolor in the Tamar estuary corresponded to that portion of the estuary with the greatest salinity variation. The density of worms varies between locations and throughout the reproductive cycle. Numbers of juveniles may be over 100 000 per m² (Clay, 1967(c)). In the Ythan Estuary, Scotland, the density of adult Hediste diversicolor was reported to be 961 per m² (Chambers & Milne, 1975).

The entrance to the burrows of Hediste diversicolor are 1-2 mm wide in soft mud and are best seen when a fork is inserted into the sediment and the handle pulled towards the user (M. Kendall, pers. comm.). Short shallow depressions radiate from the opening: these are made by the anterior part of the worm's body as it searches for food around it's hole, with the tail firmly anchored within the burrow. Burrow depth increases with body size (Esselink & Zwarts, 1989). Whilst feeding at the mud surface the worm is particularly prone to predation by wading birds and fish. The burrow is thus an important refuge in which to retreat. Esselink & Zwarts (1989) found a seasonal variation in the depth of burrows of Hediste diversicolor. The deepest burrows were seen in winter and it is likely that this deeper burrowing is an adaptation to escape low temperatures. Burrow depth was seen to level off at 15 cm because at this depth the worm can retreat from the reach of most deep-probing predators including curlews and oyster catchers. The individual burrow is a well-delimited territory but this territoriality is not extended outside the burrow (Scaps, 2002).

Substratum preferencesSandy mud
Muddy sand
Physiographic preferencesEstuary
Enclosed coast / Embayment
Ria / Voe
Biological zoneUpper Littoral Fringe
Lower Littoral Fringe
Upper Eulittoral
Mid Eulittoral
Lower Eulittoral
Wave exposureSheltered
Very Sheltered
Extremely Sheltered
Tidal stream strength/Water flowWeak (<1 kn)
Very Weak (negligible)
SalinityLow (<18 psu)
Reduced (18-30 psu)
Variable (18-40 psu)
Habitat Preferences Additional InformationNone entered
Distribution References Hayward & Ryland, 1995b, Fauchald, 1977, Clay, 1967 (c.), Chambers & Milne, 1975, Esselink & Zwarts, 1989, Smith, 1956, Kristensen, 1988, Scaps, 2002, Beukema, 1990,
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