Action: Deter birds from landing on shellfish culture gear using spikes on oyster cages
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A replicated and controlled study from Canada found that significantly fewer birds landed on oyster cages with spikes attached, compared to control cages.
Oyster bags are mesh bags, attached to floats and anchored on the seabed into which young ‘seed’ oysters are placed. They then grow and are harvested when large enough. Oyster cages are similar, but are made of rigid wire mesh.
Supporting evidence from individual studies
A replicated and controlled experiment in summer and autumn 2006 and 2007 in oyster Crassostrea virginica farms off the coast of New Brunswick, Canada (Comeau et al. 2009), found that ‘AntiCormo’ devices (spikes attached to oyster cage floats) significantly reduced the number of birds roosting on oyster cages (0-1.3 birds/100 cages at one site with AnitCormo cages; 0-42 birds at a second vs. 100-499 birds/100 cages at a control farm). Five species were seen on oyster cages (double-crested cormorants Phalacrocorax auritus, herring gull Larus argentatus, great black-backed gull L. marinus, common tern Sterna hirundo and great blue heron Ardea herodias).