The Sisterhood of the Traveling Tunicates

Botryllus schlosseri, or more commonly known as the golden star tunicate, is an invasive species to the Vancouver marina fouling communities. This sneaky critter travels free of cost, anchoring comfortably to boat and ship bases, allowing them to disperse to a wide set of destinations globally. Upon arrival, they establish themselves among the fouling communities of organisms located on docks, harbors, and boats. This could potentially alter the ecosystems functionality and structure through competition, predation, and modification of food webs. We set out on an adventure to determine whether tunicate abundance was related to light environment, salinity, and native species richness.

Marina pic 1

Photo Credit: Rohan Bhan

We arrived at the Royal Vancouver Yact Club in Coal Harbor, eager to begin our expedition and explore the serene marina for the wonderful invertebrates they were housing. My partner and I set off, eyes gleaming with excitement, to explore the boats and docks in order to obtain different lighting. Groups placed transects in two sun lit and two shaded areas, while counting the number of tunicate colonies and native species present in each. Finding golden star tunicate  colonies turned out to be harder than expected. Throughout all four of our transects, my partner and I were unable to locate a single one! Lucky for us, we had amazing comrades along with us, who were able to locate some colonies.

Our group did manage to locate a variety of native species, which included algae, sea stars, mussels, anemones and sea slugs. Many groups collected these fascinating creatures for study back at the lab. What particularly caught everyone’s attention was the spotting of an unidentifiable and beautiful sea slug. Once we had collected enough data and species, we headed back to UBC for data analysis.

 

marina2

Students and teaching assistant amazed at the beauty of the sea slugs
Photo Credit: Rohan Bhan

Upon inspection of our results, we concluded that the abundance of invasive tunicates did not have a relation to light environment or native species abundance. A potential next step would have to be examining the salinity environment effect on invasive species abundance, which we did not have a chance to cover. We were surprised and content with the fact that there was few tunicate colonies found in the fouling communities of the Royal Vancouver Yacht Club. Next time you are in the Coal Harbor area, I suggest you take a look at what is just below your feet, and you will be amazed at the beauty and diversity of these creatures.
For more information on tunicates, visit the following page:

 

http://depts.washington.edu/fhlk12/links/StudentProjects/Tun.biology.html

 

For more information on tunicates role as an invasive species and prevention, check out the following scientific article:

 

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2008.01600.x/full

 

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