Kent Island Day 7

Ciona intestanlis ascidian overgrowing mussel aquaculture cage on PEI. Bullard et al. (2009).

This past week has been quite a reality check in terms of the scientific method for me. Even with a well-planned project and an entire coastline of 5 miles accessible to work, one's hubris is easily squashed by an unfortunate ignorance of larval settlement times. Realizing that my Bryozoan might not show up until July, if at all, I came to the realization yesterday that it was time to brainstorm a new project.

As I mentioned in a previous post, I am deploying a settlement plate for a PhD student at UConn and gathering data for him on the diversity and percent cover of "fouling organisms". This side project was related to my initial project in that it examines the larval settlement and growth of invasive species including my Bryozoan (Membranipora) but also several species of Ascidians, better known as sea squirts. Ascidians have become infamous in harbor communities as nuisance species, overgrowing lobster pots, buoys, lines, docks, boats, and aquaculture cages. They greatly increase the weight and drag of these objects and cost millions each year since their introduction in the Maritimes in the 1990's. Further south in Salem, Mass, lobster pots that were once hauled in by hand now have to be winched in, and even now some are so covered that they are deemed too dangerous to haul in, since they may cause catastrophic winch failure.

The data collected from the settlement plates (essentially PVC squares hung in 1m of water) are collected via photographs of each plate every week. The images are then analyzed using photo software to determine percent cover of each species present. This, coupled with water temp readings, will determine settlement and development rate of native and invasive fouling organisms and will be analyzed with data from all over the eastern seaboard to look at temperature and spatial impacts on fouling organism growth. One question that is trying to be answered is the effect of climate change and warming waters on the settlement, growth, and dispersal of fouling organisms, particularly invasive species.

With this project in mind, I've decided I am  going to analyze settlement plate data from around Kent Island and Grand Manan and compare that to data obtained from Bowdoin's Coastal Studies Center, in southern Maine. At this point I am still deciding on a methodology and hypothesis, but it looks like I will be looking at the affect current has on the dispersal and settlement of fouling organisms with particular emphasis on invasives like the ascidians or even my Bryozoan if it shows up. So I will be making more plates and deploying them in the protected and pristine harbor formed by Kent, Hay, and Sheep Islands, two off the northern and southern ends which are exposed to currents formed by incoming and out-flowing tides of the Bay of Fundy, one or two in the protected but heavily trafficked Seal Harbor, and one at the Coastal Studies Center in Maine. In addition, I might be deploying plates off of the ubiquitous salmon aquaculture cages scattered throughout the Grand Manan archipelago as well as snorkeling around them to examine settlement on long-immersion structures. Aquaculture cages sit in the water for years, and unless removed for cleaning accumulate all sorts of fouling organisms. These fouled nets can limit water exchange between the interior and the ocean, and allow nutrients to accumulate to dangerous levels within the cage. Removal of these organisms causes up to 80% of maintenance costs, since mechanical removal is tedious and inefficient and chemicals too dangerous.

So I do have options now, albeit ones that are incredibly time intensive. But fingers are crossed that this project can go ahead as planned, since it is not dependent on the arrival of any one organism.

The days here are still bird-shell blue, and last night was an incredibly warm (for us at least, 60 degrees is warm) night. We took a petrel walk around midnight to listen for the gremlin calls of the little birds as they came back from fishing at sea to roost in their little burrows. They are extremely clumsy on land for such graceful aeronauts, and crash into trees on their decent down before finally arriving on the ground, where they proceed to stumble drunkingly about emitting giggling cackles. One strolled across our path in a very blasé manner, letting us see the robin-sized seabird a close range. It is amazing that these birds, which travel hundreds or thousands of kilometers out to sea to fish before returning to their nest, are so small. It is a wonder that they are not at the complete mercy of the winds.

Back to planning!

A Storm petrel in its Burrow. Photo cred Drew Fulton