1GTROQ, Département de biologie, Université Laval, Ste-Foy, Québec G1K 7P4
2GIROQ, Department of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke Street West, Montréal,Québec H3A 2K6
Tóm tắt
A series of multifactorial experiments were carried out, in the field and in a flume, to test the hypothesis that early recruitment of semimobile bivalve spat on an epibenthic filamentous substratum is directly related to the heterogeneity (branching pattern) and the diameter of their individual branches or filaments and to evaluate the likelihood that passive settlement processes influence bivalve larval early recruitment on filamentous natural epibenthic substrata. The experiments were carried out with three‐dimensional plastic structures similar in shape to hydroids and filamentous benthic algae—the preferred larval settlement substrata of several bivalve species in the field. Field experiments showed a highly significant effect for both branch heterogeneity and diameter. The 3‐D structures collecting the highest number of spat per unit area were those offering smallest diameter and heterogeneity. Flume experiments that used inert particles and the same silicone‐coated, 3‐D structures reproduced early recruitment abundance patterns observed on heterogeneous structures in the field. Comparison of results from the field to those from the laboratory suggests that passive settlement processes are sufficient to explain early recruitment patterns of some bivalve species on scales of order 10 cm, although alternative, biological hypotheses were not tested in this study.
