By Diane Wyse, Physical Oceanography Lab
In the spirit of sharing exciting new student research during Shark Week, we caught up with MLML and Pacific Shark Research Center graduate student Paul Clerkin. During the spring semester of his first year at MLML he took a two-month cruise aboard a commercial fishing vessel in the Indian Ocean for his thesis research. During that time, Paul collected sharks that came in as bycatch of the planned fishing activities – sharks that would otherwise have been thrown back overboard because they are not among the targeted species of commercial value. Clerkin explains that the sharks that he collected were all DOA, that very few survive under the weight of fifty tons of fish. As part of his bycatch-only collection practices, any sharks that were still alive when the fish and sharks were sorted were promptly sent back overboard to increase their chances of survival. Below are highlights from our interview with Paul on his latest fieldwork expedition.
Paul identifying sharks from a haul in the factory of the ship.
How long was the cruise?
I spent two months at sea, and then five weeks at Mauritius. During that time I processed and prepared samples to ship back to MLML. Overall I spent about 100 days out of the US. I remember because I had to get my visa renewed while I was there.
How many specimens did you bring back?
We brought in around 400 to the island, and around 350 made the trip back to MLML. It was just about a ton. On top of that I have hundreds of vertebrae and spines and around 800 tissue samples.
When you collected, was it usually a consistent number per day or catch, or did the numbers vary with time and location?
The catch amounts varied greatly, some mornings I’d wake up and have no sharks to work with, during which time I’d work on data processing, and other days I’d wake up and have 16+ hours of work sitting for me on the deck. Using bottom roller gear brought in many more sharks.
What will you do with the specimens? Are they all to be used on your thesis project, or are some saved for other projects?
The specimens will be used both for my thesis research and will be available for future research projects. We’re looking to get a lot of use out of the data. The list of possible projects and papers is pretty long.
Paul working on deck with a false catshark. Paul comments on the critter: “This species isn’t new but it is considered to be rare. I was extremely excited the first time we found one. As we caught more false catsharks over the trip I started to suspect these sharks are not as rare as previously thought. I think they just live in remote locations relatively unexplored by science. Although it is not a new species I gathered data and information on this shark that was previously unknown and will increase our understanding of this strange animal.”
Was this your longest cruise to date?
Yes, my longest cruise before this was out of AK for 90 days, but halfway through we came back to land for one day, then went back out again. After the first two weeks all the days blend together anyway.