My week began with a trip on the OIMB R/V Pluteus (a 20 feet long ship) during which I got to see critters that were totally alien to me. We were dredging along the seafloor to see what we could find. Some of our finds are pictured below, along with the shadow of “expert” photographer yours truly. For those that aren’t familiar with dredging, basically you take a large metal scoop with a net attached and drag it along the seafloor and see what turns up. I was amazed by creatures that I had never seen before magically being brought up from 150 feet of water. On the left is a fraction of our haul from dredging. At the top is a basket star, below a hermit crab inside its shell, and at the bottom is a sea cucumber. For scale I’d estimate the sea cucumber was around a foot long. This week has also seen significant strides in my own research as I move from a phase of pure inquiry and background research to a phase of execution (though a lot of inquiry remains). I have decided that as part of my project I want to trap green crabs in the South Slough Estuary to characterize their distribution and relative abundance in comparison with that of previous years. Now for a truncated history of the Invasive European green crab (Carcinus maenas).These aggressive Cancrid crabs were native originally to Europe, but hopped the Atlantic via sailing vessels in the early 19th century. They have since spread across the North American coast. My project is focused on the Coos Bay region of Oregon, where green crabs were first found in 1998. To make a long story short researchers think their larvae were carried north from the San Francisco Bay during the late 1990’s via northward moving current system. Left: A batch of green crabs caught here in the South Slough Now back to the present! This summer I will be deploying traps at key sites within the South Slough National Estuarine Research Reserve to characterize how the population in the estuary is changing. The traps I’m using are called Fukui traps and are made in Japan to catch fish, but they also happen to work quite nicely for green crabs. One is pictured here below just to give an idea of what they look like. The white canister inside the trap is loaded with bait ( tuna scraps) and staked down into the marsh sediment. Crabs can enter through either side of the trap, but once inside are unable to leave through the funnel shaped entrance. A Fukui trap in its natural habitat. The white cylinder inside is full of bait Fukui trap entrance - crabs can enter through the funnel shaped entrance, and are handily trapped inside! I’m placing the traps out in the estuary during low tide (which means getting up at 5 am!) so the whole area typically looks sort of like this: This area will be inundated with seawater within a few hours, so setting out the traps during the low tide ensures that the traps will remain underwater for a solid twenty four hours until the next low tide.
What I am doing with these crustaceans once I trap them is also super cool (though I am still figuring that part out) so tune in next week to find out!
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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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