There's a real interest in the interaction that an aquaculture farm plays in a marine environment.
One of the things that it does is give structure to a whole lot of other organisms.
So what was once just plain water that things would drift by, now is almost like an oasis.
Most of the studies in the past have been looking at the negative impact on the animals
living in the sediments directly underneath and surrounding the farm.
But there's also a potential that there's other more positive impacts of aquaculture
because we're essentially putting a bunch of energy, a bunch of food into the system
that the animals that live under and around that farm can take advantage of and increase
their fitness and their productivity.
With this research, we're looking at two main things.
One is the movement of crabs and lobsters in and around aquaculture sites, and second
is the condition of these animals.
So to follow the crabs and lobsters, what we've done, is we set out a whole big grid
of hydrophones and we glue little sound emitters onto the back of crabs and the lobsters.
And then, the hydrophones can follow the movement of the animals on the bottom by triangulation
of the noise.
Using this data, we can find out a lot about the behaviour of lobsters and crabs.
For example, were the individuals present under the culture site?
Did they exhibit foraging behaviour?
Did they exhibit habitat-seeking behaviour?
How large were their home ranges under the culture site?
“869 – they were all gone from there” "They move"
"So they're moving around!"
So the way we're doing the second part of this experiment is we're looking at the lipids
within the crabs and the lobsters that we're out sampling.
The idea is that the food that's being given to the salmon, that we think that the lobsters
and crabs are eating, has a different class of lipids inside of it.
And so, we should be able to follow those lipids, those fats, inside the crabs and the lobsters.
Lobster and crab samples were collected near the farming site to check the lipid profiles
of these individuals as well as in a reference area to compare the numbers with data from
an area free of influence from salmon feed.
During dissection of the lobster, I remove the hepatopancreas, which is similar to the
liver in that it’s an accumulating organ.
And this is the organ in which we think the omega 3/omega 6 ratio signal will be the most
off-balance, making it the best indicator of the vegetable oil signature that we expect
to see.
We’re also conducting a lab experiment to confirm how long animals have to be exposed
to this feed before we detect a signal.
What we’re doing in the lab is basically calibration work.
We have 60 lobsters, all in individual tanks, and for about the past two months now, each
lobster has been on a precision-calculated diet ranging from between 0% and 100%.
So at the end of the experiment, we’ll collect samples of hemolymph, which is more or less
the lobster equivalent of blood, and we’ll send it off to the lab so they can do a detailed
analysis of all fatty acids detected in the hemolymph.
And this helps us to make the connection between the lobster’s lipid profile and the proportion
of its diet coming from aquaculture feed.
Once the method is calibrated, we’ll be able to take any lobster out of its natural
environment, do the same analysis and compare the result with our lab findings.
Then, by comparing the lipid profiles of lobsters in different regions, we’ll get a better
idea of how much of an influence aquaculture feed has on bottom-dwelling invertebrates
living near aquaculture sites.
And so, this whole interaction is important to understand because there's a lot of interest
on the part of the fishermen for example that are fishing lobsters in the area, and whether
there's any benefits or problems that are occurring because of that, but also to the
farmers.
I mean, they want to know what's going on around their farm so they can at least be
benign and, possibly they can even enhance some things that we want to enhance.
I like the work that I do because the results from my research are used in the management of aquaculture.
That's to say that we're now looking at aquaculture in a much more holistic point of view than
we used to in the past and that's, to some extend, based on the research that I've been
doing for the past few years.