Last month, I received an invitation to join the Island Institute as they visited a small mussel farm off the coast of Islesboro and I was more than happy for this opportunity to spend my workday outside boating around in the waters further down Maine’s coast. On the morning of July 24th, myself and eight others boarded the Fish Hawk and sailed to the site of Marshall Cove Mussels where Shey Conover and her crew were tending one of their rafts filled with mussel lined rope. As we boarded the barge, the crew demonstrated feeding the mussel lined rope through a rope stripping machine that removes the mussels and these newly detached mussels then took a trip through a declumper/grading machine before being bagged and tagged for further processing or distribution.
A long preferred settling place for blue mussels, the Gulf of Maine has six identified quality mussel beds from Casco Bay to Jonesport with the edge of Hancock County & most of Washington County seeing both blue mussels and Baltic mussels due to our cooler water temperatures. Landings for this commercial fishery peaked in 1995 at 37.5 million pounds and a value of $2.3 million. From 2014 to 2023, landings have gone from 13.3 million pounds to 6.1 million pounds with this decrease coming from a variety of factors including diminished mussel bed availability, overfishing, predation, and competition with invasive species such as the green crab. But, with this decrease in landings, we have seen an increase in value. In 2023, the 6.1 million pounds landed had a value of $4.4 million – a sizable contribution to our state’s economy.
Maine’s farm raised mussels had a value of nearly $4 million in 2022 and 2023 with room for growth. To keep initial capital costs lower than what they could be, very small farms have the ability to use mostly manual labor to seed the lines/bottom and in harvesting the crops. However, as mussel farming is an economy of scale, as the farm grows to reach a profitable status there will likely be a need to invest in a rope seeding machine, rope stripping machine, and a declumper/grading machine – all at a sizable cost and likely coming from Europe.
Even though they’re grown in the same water, there are some differences between farm raised and wild caught mussels. Wild caught mussels take 7 or more years to reach harvestable size and have less of a meat yield than farm raised do as wild mussels expend much of the energy they consume on growing a thick shell to protect themselves from predators and the tide. It takes just 18 to 24 months from seed collection for farm raised mussels to reach a harvestable size of 2¼” to 3” with higher meat yields as they’re able to focus more on consuming energy to grow. Farm raised mussels are also able to be harvested before pearls get the chance to develop.
Mussels can be farmed using a couple of methods. The bottom culture method involves thinly spreading mussel seed over an area of leased bottom and allowing them to grow. This method takes more space to grow fewer mussels and is more susceptible to predation whereas using a suspended culture method takes advantage of the additional water column space allowing for 5 times the harvest. Suspended mussel farms place mussel seed on old, fuzzy rope that’s suspended in rafts and surrounded by predator nets to help protect the mussels from starfish and the sea duck which can dive 35’ to consume their weight in mussels each day. Growing mussels on rope also allows for the ropes to get treated with a lime and sea water solution to prevent hydroid fouling of the mussels.
As always, if you’re interested in diversifying with an aquaculture business, it’s important to speak with your community members about your plans as there are many commercial and recreational uses of our waterways to take into consideration. Check out this link from Isleboro Marine if you’d like to see a video on Marshall Cove Mussels.
Interested in learning more about ways to diversify your working waterfront business? Connect with me today!
Photos by Jack Sullivan.