Larval development of the cockleChione stutchburyi(Bivalvia: Veneridae) reared in the laboratory

Abstract

Larvae of the New Zealand cockle Chione stutchburyi (Wood, 1828) reared to settlement in the laboratory are described. They are characterised by dissimilar shoulders with a large, broadly rounded anterior shoulder and end, and broadly rounded umbo, typical of the Veneridae. Setting occurred after 20 days at a minimum length of 180 pm. Shell dimensions increased linearly during larval development but hinge length did not. The L:H ratio decreased from 1.27 at L = 100 to 1.1 at L = 200 and .the L:D ratio from 1.95 at L = 100 to 1.59 at L = 200. An SEM study revealed that the larval hinge is characterised by a toothed provinculum forming a broad medial projection on the right valve, opposing two projections on the left valve. Conspicuous flanges on the anterior and posterior shoulders of the left valve fit into corresponding grooves of the right valve.

Local-scale variation in trace elemental fingerprints of the estuarine bivalve Austrovenus stutchburyi within and between estuaries

“…Spawning typically occurs in the warmer summer months, with peak spatfall previously observed in Whangarei Harbour between December and February (Lundquist & Broekhuizen 2012). The dispersal period lasts 2 to 3 wk, after which settlement occurs at a size of approximately 180 µm (Stephenson & Chanley 1979). The shell of infaunal bivalves is entirely composed of aragonite, with calcite not being deposited (Green et al 2013).…”

Predicting suitability of cockleAustrovenus stutchburyirestoration sites using hydrodynamic models of larval dispersal

“…Peak spawning occurs in austral summer (January to april) and peak spatfall is observed between February and may (Stephenson & Chanley 1979). The larval period is estimated at 2-3 weeks (Stephenson & Chanley 1979;Strathmann 1987), with settlement at a size of approximately 180 µm (Stephenson & Chanley 1979). Cockles exhibit postsettlement movement primarily via bedload dispersal (Turner et al 1997;Lundquist et al 2004a), and adults have been observed crawling through surface sediments at rates of up to 1.3-1.7 m per day (hewitt et al 1996).…”

“…Peak spawning occurs in austral summer (January to april) and peak spatfall is observed between February and may (Stephenson & Chanley 1979). The larval period is estimated at 2-3 weeks (Stephenson & Chanley 1979;Strathmann 1987), with settlement at a size of approximately 180 µm (Stephenson & Chanley 1979).…”

“…Simulations began on either a neap, mean or spring tide, and Lundquist et al-Evaluating cockle restoration sites continued through a 14day period to represent the minimum period that cockle larvae spend in the water column (Stephenson & Chanley 1979). For each tidal condition, we simulated nine combinations of wind strength and wind directions (calm winds, and mean and strong winds simulated from each of four directions: northeast, northwest, southeast, southwest).…”

“…hydrodynamic models were run for 16 days, with particles released after a 2day hydrodynamic startup to allow the hydrodynamic model to generate appropriate model circulation after initial zero flow and constant water level conditions. Particles were tracked for 14 days, incorporating a minimum of a 2week larval life span of cockles (Stephenson & Chanley 1979).…”