At Hurricane Island this summer, we are working on setting up research on scallop growth rates using three different culture techniques.

Photo: Alex Griffith (HICSL)

Lantern nets are a traditional Japanese method of growing scallops that is currently widespread in the Gulf of Maine. The nets look like an accordion, and serves as an apartment building of sorts, with ten levels for scallops. These nets are suspended from floats or lines off the bottom, limiting damage from bottom strikes and predation. However, their location close to the surface means fouling by algae and organisms like tunicates that prefer to feed higher in the water colum, which dramatically reduces water flow to the scallops. Further, high densities of scallops can effect growth rates through food competition and "knifing," wherein scallops can pinch or cut other scallops with their open shells.

Bottom cages are less common in the Gulf of Maine, but have a similar concept to lantern nets. Cages hold six mesh "bags," and these cages are weighted to sit on the bottom. Biofouling is still an issue with these cages and bags, but they do not seem to foul as quickly as lantern nets. They do require more materials, take up more space, and are overall more expensive than other options. Much like lantern nets, high densities can lead to lower growth rates. The picture above shows a bottom cage off of Hurricane island viewed from the top; here you see two bags of scallops, and beneath each are two more for a total of six bags.

Photo: Portland Press Herald

Ear-hanging is relatively new for the Gulf of Maine, but is now quite widespread in Japan and is a favored method. Scallops are not placed in a net or cage; instead, a hole is drilled through the "ear" of the scallop, and the scallop is then threaded onto a plastic hanger attached to a strand of rope. This plastic hanger is hooked, so a scallop will not fall off. This method limits the amount of gear needed, and thus is cheaper and easier to clean. Scallops do not touch neighbors, and so are free to grow unconstrained by space or food competition. Further, they spend more time with their shell opening and closing while the feed, excercizing the edible adductor muscle and accelerating growth. However, drilling these holes in scallop ears are incredibly time-consuming by hand, and machines that automate the process are tens of thousands of dollars. Ear-hanging scallops are also less protected from predators and the elements. Mortality can thus be high after a heavy storm, especially if the lines are not far enough from the bottom. 

Certain methods may yield larger scallops, but the cost per scallop to the farmer may be more expensive compared to other methods, and so it is not the only factor when selecting culture techniques. We are hoping to continue taking monthly data on growth rates this summer and in following summers, with the goal of demonstrating which methods provide optimal growth.

Adult scallop, 3 years. Note eyes on rim of mantle

Juvenile scallop (less than a centimeter), less than a year. Collected using spat bags off of Muscle Ridge

Madison and I spend a lot of time counting and measuring scallops!

Hurricane Island

It's been three (!) years since I've updated this blog in Madagascar. In my quest to keep writing as much as possible about field experiences, I've decided to restart it. In the intervening time, I've completed research with the Bowdoin Marine Science Semester, graduated from Bowdoin in the spring of 2016, worked for the Wilderness Society performing wilderness surveys in California, assisted on a Smithsonian Institue expedition to Curacao tracking reef community changes to climate change, and was a freshwater scientist on Operation Wallacea's 2017 Dominica expedition. In retrospect, I wish I had kept writing for these experiences.

I am currently working as a Research Assistant at the Hurricane Island Center for Science and Leadership, located off the coast of Vinalhaven in mid-coast Maine. Founded in 2009, it was conceived with the vision of providing a campus for environmental and sustainability education for all ages, as well as a center for cooperative research. The island itself has a long history of human settlement, particularly at the end of the 19th century as a booming granite quarry town with almost a thousand people at its peak. Impressive for an island of 125 acres! These signs are all over the island, ranging from the yawning quarry pit in the south to the twisted and rusted metal artefacts dotting the landscape. Before HICSL, and after the crash of the quarry town, Outward Bound used the island for a leadership and outdoors skills center.

I am involved this summer with continuing cooperative aquaculture research which has been ongoing for the past few years. In particular, we are interested in growing scallops (Placopecten magellanicus) and sugar kelp (Saccharina latissima) using different culture techniques to establish optimal strategies for high growth. Shellfish and macroalgal culture are incredibly exciting to me, and I think they can play a huge role in saving the world. How??

To answer this, one must first consider the recent biological and cultural history of the Gulf of Maine's fisheries. Cod (Gadus morhua) was the dominant fishery for much of the early and mid 20th century in the Gulf of Maine before lax regulation, an abundance of industrial fishermen, and incredibly high-tech boats dramatically crashed the population from the 1960s-1980s (https://www.nefsc.noaa.gov/history/stories/groundfish/grndfsh2.html#srd). This story is eloquently detailed in Mark Kurlansky's book Cod: A Biography of the Fish that Changed the World. 

Unlike some places that were devastated by the crash of the Cod fishery, fishermen in the Gulf of Maine had transitioned to something superabundant: the American Lobster. While the American Lobster fishery has been in place and quite common before the crash of the Cod fishery, it came to define the area as the only viable commercial fishery post-cod collapse. Indeed, lobster has come to define the very essence of Maine. That of family fishermen and women, local co-ops, and an incredibly well-managed fishery (http://geo.coop/node/654). In all, lobstering in the Gulf of Maine should be a viable long-term fishery with current management strategies. Enter climate change.

The Gulf of Maine is warming faster than 99% of earth's water bodies. This is caused by a shifting Gulf Stream and a weakening cold Labrador current, in addition to overall warmer years. This is bad news for lobsters, who at temperatures around 70 degrees begin shutting down their internal organs (https://www.nytimes.com/2018/06/21/climate/maine-lobsters.html. Indeed, lobster populations have been shifting ever northward in the past decade. Where lobsters were once caught in abundance in the Long Island Sound, there are but a handful of lobstering vessels left catching meager hauls (https://www.pressherald.com/2018/01/22/lobster-boom-over-as-population-starts-to-decline/). This is an example of what Steneck et al. (2011) have called a gilded trap (https://www.ncbi.nlm.nih.gov/pubmed/21797925), where a local fishery is too economically dependent on the economic success of a single target organism. We have seen this in Newfoundland post cod collapse, which shut down most of the province's fishery industry. How do we ensure that lobstermen in the Gulf of Maine will have supplemental income, and even a replacement industry, should lobsters move north to Canada, as they are predicted to in the next twenty years?

Aquaculture can be considered sea farming, where "farmers" tend to organisms they have grown from seed spat to maturity for harvesting. In some cases, no capture fisheries are required to sustain these sea farms, particularly in the case of shellfish and macroalgae. Because they are farmed, many factors dictating fishery abundance can be controlled, from nutrient input to juvenile survival success. Unlike capture fisheries, aquaculture is more reliable year to year. Further, sea farming shellfish and macroalgae can be highly sustainable, given that shellfish require no food if in a highly productive area, and algae remove nutrients and Carbon Dioxide from the water.  If we can enable fishermen and women to expand their operations to aquaculture, we will have avoided to gilded trap and set up communities for climate resilience (http://www.anthropocenemagazine.org/2018/06/for-a-more-sustainable-food-future-molluscs-and-small-fish-may-be-the-answer/).

So, we have a huge vested interest in researching economical and sustainable methods for aquaculture. Hurricane Island, situated near the heart of Penobscot Bay and Maine's aquaculture and lobstering industry, is perfectly set up to research ideal aquaculture set-ups for both the environment and surrounding communities. It is worth noting that we are working actively with local aquaculturists, fishermen and fisherwomen, and state and university scientists in this cooperative venture.

I am thrilled to be part of the team on Hurricane Island this summer working on research and education. I hope to add posts updating specifics of our work with scallops and kelp this summer.