ROBUST AND INEXPENSIVE TOOL DEVELOPMENT FOR MONITORING FLOW REGIME WITHIN SHELLFISH AQUACULTURE GEAR

Despite such promising technological and economic advancements in shellfish aquaculture over the past several decades, limitations to production still exist (e.g. gear restrictions, leasing and permitting hurdles, operation costs of farms). To promote future growth in shellfish production, more research is needed to improve the gear efficiency of cultured shellfish. Among suspension feeding bivalves, optimizing flow to maximize food delivery and export waste is believed to be an important governor of shellfish growth. However, little attention has been given to these relationships relative to other aspects of aquaculture research. A major impediment for optimizing flow within gear has been the lack of tools to monitor the physical environment within different gear types. Additionally, tools must be both robust and affordable to provide research-based guidance to shellfish producers and researchers to increase production.

The goal of this research was to develop a series of inexpensive and robust tools that can accurately monitor the physical environment within shellfish aquaculture cages to understand relationships between ambient and internal physical forces generated by grow-out cages, and shellfish production. We adapted several tools with a proven track record for use in shellfish cages; specifically, clod cards (flow), ammonium peepers (residence time and waste accumulation), and accelerometers (jostling). The tools were modified for use in aquaculture and validated through a series of field trial experiments that intentionally altered the internal physical environment within oyster grow-out cages (e.g. fouling management, cage stocking density and mesh size), to assess the sensitivity of the tools and validate their use for optimizing shellfish production.

The development of reliable tools that relate shellfish growth rates to the physical environment within cages represents a major step forward towards gear optimization. Furthermore, each tool was intentionally designed to be inexpensive and user-friendly to promote use by famers and collaboration with other researchers wishing to help optimize gear at the farm scale.