Last week I left my readers with a suspenseful final question: What happens to the crabs that I collect out in the estuary? Now for the answer! All of the invasive green crabs I catch out in the field are brought back to the lab. In the lab we measure the maximum width of their carapace (the hard upper shell), their weight, sex and color of the abdomen. Male and female crabs can be distinguished by the shape of their, “apron,” a distinctly shaped flap on their underside. After the data is recorded crabs are then sent to their final resting place in the freezer where they are being preserved for a genetic study. So why record these data once I return to the lab? Why all this trouble? By looking at crab size we can figure out how old they are. Because green crabs generally spawn during the same period of the year, crabs that are similar in size are likely to be the same age. By recording the sizes, weights and color of the crabs we can get an idea of when they were spawned. By looking at the conditions during years when a lot of crabs were spawned we can begin to understand which years had the most favorable conditions for green crab survival.
I am trapping at 7 locations in the SSNERR where previous researchers have looked in order to figure out how the abundance of crabs in the estuary has changed. I also want to figure out how the number of green crabs we catch during a 24 hour trapping period relates to what the physical conditions of the estuary are like. Physical and chemical gradients in estuaries vary on a daily basis and I am interested in how these factors impact the ability of green crabs to survive. I’ve even had good fun this week outside of my research with the fellow interns in my cohort. We embarked on a camping trip to the Cape Arago state park campground and enjoyed a night of s’mores and campfire fun. The following morning we ventured out for exploring some of the tidepools at the state park’s south cove. Once again I was amazed by the diversity of all the invertebrates teeming amongst the briny boulders along the shore. Unfortunately I wasn’t able to get any pictures due to a depleted phone battery, but we did manage to get a group photo of our cohort at the pools.
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AuthorI’m a rising junior at the University of Pennsylvania studying ecology and evolutionary biology. When I’m not doing science I love doing pretty much anything outdoors. I’m an avid backpacker, runner, paddler and rockclimber. Finally I love to read fiction in pretty much any form. Archives
August 2018
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