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Burrowing Behavior, Substratum Preference, and Distribution of Schizaster canaliferus (Echinoidea: Spatangoida) in the Northern Adriatic Sea
Author(s) -
Schinner Gottfried O.
Publication year - 1993
Publication title -
marine ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 58
eISSN - 1439-0485
pISSN - 0173-9565
DOI - 10.1111/j.1439-0485.1993.tb00371.x
Subject(s) - bay , silt , sediment , range (aeronautics) , settling , oceanography , mediterranean sea , substrate (aquarium) , ecology , geology , mediterranean climate , biology , environmental science , geomorphology , materials science , environmental engineering , composite material
.Schizaster canaliferus , an endemic Mediterranean spatangoid, is common in the Bay of Piran (Northern Adriatic Sea). The abundance and distribution of this burrowing species is related to sea water depth and particle size distribution of the substrata. Populations are limited to silt/clay sediments in protected sublittoral areas of the Bay, where densities range from 1.9–2.6 individuals · m ‐2 . Preferred sediments range from medium to fine silt (2–20 μm). Burrowing activity was found to be functional only in fine sediments similar to those naturally inhabited; it did not occur in sandy sediments (>63μm). Burrowing rates were positively correlated with temperature, suggesting that burrowing speeds are greater in summer than winter. S. canaliferus is limited to the upper, oxygenated sediment layers and always burrowed just above the Redox‐Potential‐Discontinuity‐layer (RPD). At field study sites, the RPD ranged from 37 to 45 mm, while echinoid burrowing depths ranged from 30 to 45 mm. Laboratory manipulations of the RPD‐layer indicated that when this layer is displaced to 8cm depth, sea urchins responded by burrowing deeper, settling at depths just above the reoxygenated sediments. Populations of S. canaliferus in the Bay of Piran were randomly dispersed and size frequencies of individuals were unimodal, indicative of regular annual recruitment. 5. canaliferus is highly substrate specific and does not appear to be as widespread in the Adriatic Sea as earlier studies indicated. Its restricted distribution may be indirectly related to morphological constraints of the burrowing apparatus, which limits its occurrence to fine‐grained sediments within protected areas. Summary Schizaster canaliferus has been studied in the Bay of Piran (Northern Adriatic Sea). The abundance and distribution of this burrowing sea‐urchin is related to sea water depth and particle size distribution. Populations were limited to silt/clay sediments in protected sublittoral areas of the Bay. Burrowing activities were found to be functional only in fine sediments, similar to those naturally inhabited. Burrowing rates were positively correlated with temperature. S. canaliferus was limited to the upper, oxygenated sediment layers and always burrowed just above the Redox‐Potential‐Discontinuity‐layer (RPD). S. canaliferus is highly substrate specific and does not appear to be as widespread in the Adriatic Sea as indicated in earlier studies.