Tuesday, June 23, 2015

2015 Megan: First Few Weeks

Hello! My name is Megan Peavey and I will be a senior next fall at the University of New Hampshire studying Marine, Estuarine, and Freshwater Biology. I am very excited to be working with NH Sea Grant as a Doyle Fellow this summer. I am working with two mentors in fisheries and aquaculture – Michael Chambers and Gabriela (Gabby) Bradt. In the first few weeks, I have already learned so much and I’ve started some different projects that I will share with you!

One project I’ve been working on with Michael Chambers and a few others this summer is an integrated multi-trophic aquaculture (IMTA) of rainbow trout, blue mussels, and seaweed at the UNH aquaculture site off the coast of the Coastal Marine Lab in New Castle, NH. The goal of this ongoing project is to investigate sustainable aquaculture practices in the NH area, as well as get local fisherman involved in utilizing aquaculture to augment their wild catch. So far, we have received the fish from the hatchery in Ossipee, NH and placed them within nets we coated with blue “anti-fowling” paint underneath the Judd-Greg Research pier. Using the anti-fowling paint helps prevent other organisms (such as algae, tunicates, bryozoans, etc.) from colonizing on the nets and reducing the efficiency of the system. We feed the fish a moist diet that is designed to help the fish transition from fresh to salt water twice a day. Once the fish get a bit larger, we will transport them to the UNH aquaculture site location.

As for the blue mussel and seaweed components of the project, we are cleaning off old mussel lines and preparing the new ones to collect the mussel spat (mussel larva that has attached to a surface). Sugar kelp is the species of seaweed usually grown and it is a winter crop, meaning it is grown all winter and harvested in the spring. Although sugar kelp grows well in the winter, it doesn’t grow as well in warmer temperatures and too many epiphytes grow upon it during the summer months making it unsuitable for summer. Last week, we collected two types of seaweed from Fort Stark: Gracilaria and Irish Moss. We are investigating the possibility of growing these two species in the summer alongside the blue mussels and rainbow trout.
Gracilaria (thin red seaweed) and
Fucus species (green thicker seaweed)
Irish Moss

With Gabby Bradt, I’ve been working on a project focusing on the European Green Crab (Carcinus maenas). These crabs are an invasive species that were introduced from Europe in the 1800s, and again in the 1900s. By now, they have become well established along the East Coast of the U.S. and are detrimental to our ecosystems here, devastating populations of mussels, clams, and other species. This is not only a problem for ecosystem structure, but also economically for fishermen and clam diggers. The goal of our project is to better understand molting behavior and look for morphological cues for molting in green crabs. With this information, we hope to create something similar to the soft-shell industry for blue crabs. After molting, crabs are in the soft-shell stage, and at this point they are usually fried or cooked in a variety of ways, and eaten. Although this is common practice for blue crabs, it isn’t with green crabs. Since green crabs are fairly small, they are more marketable as a soft-shell crab than a whole crab that a chef would have to pick the meat out of. The idea is that one way to control the population of European Green Crabs would be to eat them, similar to projects in Florida that aim to control lion fish populations that are out of control.

So far we have collected 100 female crabs, and 12 male crabs at the Hampton Public Pier in Hampton, NH to use in our experiment. We are conducting the experiment in two outdoor tanks at the Jackson Estuarine Laboratory in Durham, NH. 50 of the female crabs are in one tank - 25 are controls, with nothing done to them except for tagging, while the remaining 25 have scratched carapaces along with their tags. All remaining crabs (50 females and 12 males) are in a tank together to observe if pheromones from different sexes have any influence on molting.

Green Crab from control group

Trap used for catching crabs @ Hampton Pier
Green Crab from experimental (scratched carapace) group

In the past few weeks I’ve learned a lot about experimental design and how to adapt when something doesn’t work or needs to be adjusted. I have also learned all sorts of marine skills from knot tying to net repair, and I’m sure this is only the beginning and it has been a whirlwind first few weeks. Stay tuned for an update on these to projects as well as others to come!

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