Survival of outplanted juvenile clams 2017
This spreadsheet shows numbers of recovered live and dead juvenile Manila clams outplanted at 4 field sites in the inside waters of Washington state over 2 months in the summer of 2017. Each replicate (e.g., A1) initially had 20 ‘large’ and 20 ‘small’ clams; avg size of large clams at the start of the experiment was 6.2 mm length, of small clams was 3.2 mm. Clams of both starting size classes were placed in windowscreen tubes filled with sediments at two elevations on the shore: 'high' at +1m MLLW, 'low' at +0.3m MLLW. Some tubes were 'open' to predators, others had a window-screen 'top' to exclude all predators. Some tubes had a mix of pebble and sand ('pebble'), others had crushed shell added to buffer porewater pH ('shell'). Each treatment combination was repeated 5 times (set A through E) along a 50m horizontal transect, but not all 5 tubes were recovered at all sites and elevations. Survival varied highly among sites and treatments, but not substantially between elevations. Tops tended to greatly increase survival, but not at all sites.