A histopathological-biochemical health and condition assessment of farmed blue mussels in a changing Gulf of Maine

View the project final report

Commodities

• Miscellaneous: Blue Mussels

Practices

• Animal Production: animal protection and health, aquaculture
• Education and Training: on-farm/ranch research
• Production Systems: agroecosystems

Economic and environmental sustainability of Maine working waterfronts has declined as capture fisheries that
support them have consolidated or collapsed. Adoption of sustainable aquaculture has become critical to the
diversification of the working waterfront in Maine. Emerging as a foundational aquaculture species in Maine are
rope-grown farmed blue mussels (Mytilus Edulis). Considered among the highest quality mussels on the market
they command a premium yielding market prices upwards of $8.00/lb with a seemingly insatiable market demand.
Any yet, the blue mussel in the Gulf of Maine (GoM) is struggling in the face of climate change. The GoM is
rapidly warming (Pershing et al., 2015), producing physiological disruptions (Lesser, 2016) and bringing with it
acidic waters, invasive predators, competitor species. The result is an alarming decline in wild intertidal
populations (Sorte et al, 2016.) Furthermore, in summer 2016 an unexplained mortality event of farmed mussels
led to a loss of ~$60,000 worth of mussel stock on one farm in Casco Bay, Maine.

Despite this, there has been no assessment of the condition, pathology, or parasitology of farmed blue mussels in
Maine. We propose an intra-seasonal health and condition assessment through combined histopathological and
biochemical analysis of pathology, reproduction and fatty acids in mussels farmed in Casco bay, Maine.
Results will inform farmers of when their crop is healthy, stressed, and nutritious, the development of best
management practices to mitigate product loss, and serve as an important pathological baseline for monitoring
farmed mussel populations as the GoM and climate continue to change.

OUR GOAL IS: To assess the intra-seasonal health and condition of farmed mussels in Casco Bay, Maine to
provide valuable information to farmers on when their crop is the most healthy, stressed, and nutritious.
OUR QUESTION IS: How do fatty acids, storage tissue abundance, reproduction and pathology vary in farmed
blue mussels in Casco Bay, Maine both temporally and spatially?

OUR OBJECTIVE IS: Through a partnership with Bang’s Island Mussel Farm in Casco Bay to use a combination
of environmental monitoring, histopathology (a cost effective tool used to assess health and condition of mussels)
and fatty acid analysis (measure of energy storage vs. expenditure due to metabolic maintenance) to determine how storage tissue quantity and quality (Adipogranular and Vesicular Connective Tissues coupled with fatty acid
quantity and profile) as well as the severity and presence of pathological indicators vary seasonally across farm
sites with different environmental conditions and within the same site.

This will serve as an important pathological baseline for monitoring farmed mussel populations in the future allow
for the development of best management practices to mitigate product loss either through limited handling during
periods during stress, optimization of stocking densities, raft spacing.