DISAPPEARING SPAT ON NEW ZEALAND’S GREENSHELL™ MUSSEL (Perna canaliculus) FARMS, MAGNITUDE, CAUSES, AND POSSIBLE SOLUTIONS
The Greenshell™ mussel (Perna canaliculus) industry is New Zealand’s largest and most valuable aquaculture industry, and yet despite its success, the industry remains extremely inefficient at converting seed mussels (“spat”) into market-ready adults. The cause of this inefficiency is largely due to high spat losses that often take place early in the production cycle, shortly after seeding out (i.e., within the first 3 months of production). However, until recently, little was known about the magnitude of spat losses across the industry, and the potential causes of these losses. In turn, this lack of knowledge made it difficult to begin to develop any practical solutions aimed at addressing the problem and reducing spat losses. This presentation will summarize the findings of several studies which were undertaken to 1) begin to quantify the magnitude of spat losses both on individual farms and on an industry-wide basis, and 2) to start to identify some likely causes of the problem. The presentation will demonstrate that, despite considerable research effort, the exact causes of spat losses remain poorly understood. However, this presentation will also outline the results from initial studies that show that land and/or sea-based nursery culture (i.e., growing spat to larger sizes prior to seeding) may be a promising approach to finally solving the problem for production.
The Greenshell™ mussel (Perna canaliculus ) industry is New Zealand’s largest and most valuable aquaculture industry, and yet despite its success, the industry remains extremely inefficient at converting seed mussels (“spat”) into market-ready adults. The cause of this inefficiency is largely due to high spat losses that often take place early in the production cycle, shortly after seeding out (i.e., within the first 3 months of production). However, until recently, little was known about the magnitude of spat losses across the industry, and the potential causes of these losses. In turn, this lack of knowledge made it difficult to begin to develop any practical solutions aimed at addressing the problem and reducing spat losses. This presentation will summarize the findings of several studies which were undertaken to 1) begin to quantify the magnitude of spat losses both on individual farms and on an industry-wide basis, and 2) to start to identify some likely causes of the problem. The presentation will demonstrate that, despite considerable research effort, the exact causes of spat losses remain poorly understood. However, this presentation will also outline the results from initial studies that show that land and/or sea-based nursery culture (i.e., growing spat to larger sizes prior to seeding) may be a promising approach to finally solving the problem for production.