|An assessment of longshore movement in Donax serra Röding (Bivalvia: Donacidae) on an exposed sandy beach|Dugan, J.E.; McLachlan, A. (1999). An assessment of longshore movement in Donax serra Röding (Bivalvia: Donacidae) on an exposed sandy beach. J. Exp. Mar. Biol. Ecol. 234(1): 111-124. dx.doi.org/10.1016/S0022-0981(98)00145-2
In: Journal of Experimental Marine Biology and Ecology. Elsevier: New York. ISSN 0022-0981, more
Detection; Fauna; Metals; Tagging; Bivalvia [WoRMS]; Donacidae Fleming, 1828 [WoRMS]; Donax serra Röding, 1798 [WoRMS]; Marine
Bivalve; Metal detector; Mobile fauna; Tagging
|Authors|| || Top |
- Dugan, J.E.
- McLachlan, A.
Peak abundances of intertidal populations of a donacid bivalve, Donaxserra, occur 10–23 km from major river mouths along exposedsandybeaches of log-spiral bays on the coast of southeast Africa. Postsettlement eastward movement of D. serra from areas of spat settlement by prevailing longshore currents has been suggested as the mechanism which results in the observed population distributions. To estimate the net rates of longshoremovement in intertidal D. serra on one of these exposedbeaches, we developed and used a novel technique. A metal detector was used to track net change in the positions of intertidal juvenile and adult clams (37–67 mm shell length, 1–3+ years) with aluminum tags glued to the shells over a 3-month period during the austral fall and winter. Estimated net longshoremovement of tagged clams ranged from 0.19 to 0.80 m day-1. The net movement of tagged clams was primarily to the east along the beach but the direction of longshoremovement varied during the study. Net rates of longshoremovement were not correlated with clam size. The burrowing rates and the condition of recaptured tagged individuals were not significantly different from untagged clams after 2 months. The results of this study suggest that average longshoremovement rates of intertidal clams, >1 year of age, along the beach are low and the animals are relatively sedentary. The technique developed and used here to estimate net longshoremovement rates in D. serra allowed us to successfully recapture and track tagged individuals with very minimal disturbance to the intertidal habitat and associated fauna. Use of this novel technique could potentially enhance investigations of postsettlement movement, growth, zonation, competitive interactions and other aspects of the ecology of mobile soft sediment macrofauna.