Depth Selection and In Situ Validation for Offshore Mussel Aquaculture in Northeast United States Federal Waters

Abstract

As mariculture progresses offshore in the US Exclusive Economic Zone, technical and ecological challenges need to be overcome, such as the choice of suitable sites that favor the production of target species. The offshore culture of blue mussels, Mytilus edulis, is performed with submerged longlines and mussels need to withstand more motion than on coastal sites. Temperature affects the ability of the byssus to adhere to farming rope, while chlorophyll concentration provides an estimation of food availability. Together, these are important factors in predicting the suitability of offshore mussel farms. To identify suitable depth of submersion for mussel ropes in New England federal waters, historical oceanographic data of temperature and chlorophyll a from 2005 to 2012 were used. The results suggest that mussel ropes were submerged during summer to a minimum depth of 15 m in northern and a 20-m depth in southern areas of New England where temperature is at a species-optimum and phytoplankton biomass is abundant. For the site offshore Massachusetts, in situ biodeposition measurements validated predicted depth, confirming satisfactory mussel performance. Promising local areas have shallow thermoclines, such as offshore Long Island, Cape Ann and New Hampshire. Recommended depths can be adjusted to future temperature increases associated with climate change.

Commercial Performance of Blue Mussel (Mytilus edulis, L.) Stocks at a Microgeographic Scale

“…As an experimental study on giant scallops (Placopecten magellanicus, G. 1791) recruitment [60] demonstrated an interaction effect of thermocline and turbulence on the settlement success, we think the depth in BP may have impacted the recruitment success of mussels on collectors. Several field studies confirmed that blue mussel settlement on artificial collectors is influenced by the presence of a thermocline and depth [13,61,62]. However, we have no indication that collectors' depth is an important driving factor for spat supply differentiation between lagoon and offshore sites in this area.…”

“…However, nearshore bivalve culture is severely constrained by space limitation and user conflicts [8,9], climate change and fluctuating environmental conditions [6,10], carrying capacity limits or other environmental concerns [4,11], and the need for improving mussel performance and productivity [8,12]. On the basis of several pilot projects conducted in different countries over more than a decade, the establishment of offshore suspended long-line mussel farms has been shown to be promising [4,[8][9][10]13] in areas like the Îles-de-la-Madeleine Archipelago (Gulf of St. Lawrence, Québec, Canada) [14,15].…”

Flash flood simulation and valve behavior of Mytilus galloprovincialis measured with Hall sensors

“…For example, a precautionary “early harvesting” or the moving of the mussel cultivation off‐the‐coast or offshore could be the best practice to adopt. The last two options are currently considered promising in mussel aquaculture to reduce the risk due to changing environment (Mizuta & Wikfors 2019).…”

The carrying capacity of the seas and oceans for future sustainable food production: Current scientific knowledge gaps

“…Production carrying capacity was reached or even exceeded in several inshore areas (Smaal & van Duren, 2019). The possibility of offshore culture is now explored in many areas around the world, e.g., the U.S. east coast, Tasmania, Great Britain, and Belgium (Mizuta et al, 2019;Villalba et al, 2022).…”