3/31
Today I went to the University of New Hampshire's Jackson Estuarine Lab in Durham, NH. I removed the nine crabs Dr. Bradt collected last week and placed them in a bucket while I cleaned the two tanks we will be using this summer. The tanks were set up with water coming from the estuary and a drain system. A pipe is attached to the drain to control the depth of the tanks and netting was zip tied over the pipe to prevent the crabs from crawling out. In addition to cleaning out the tanks, I also measured and took pictures of the nine crabs. A dorsal and ventral view were captured and the crabs were measured from the widest part of their carapace. Once they were photographed, measured, and described, I placed them back into one of the clean tanks. At the end of the day I went back to UNH to Dr. Bradt's office so we could discuss our experimental design and where we should place our traps. Ideas were thrown around, but nothing is set in stone yet. Can't wait for tomorrow!
Description of what we are seeing in pictures: We are looking at male crabs specifically because they molt in the Spring, while females molt in the late Summer. The purpose of the dorsal view picture is just to be able to identify the crabs, however once our experimental design is set up, the crabs will be in labelled containers to make sure we are describing the correct one. The ventral view is most important because it allows us to see which stage the crabs are in. We are looking to see if the crabs are in pre molt phase or imminent phase. If they are in pre-molt phase then the crabs should molt within 1-3 weeks. If they are in the imminent phase then they should molt within 1-3 days. We can tell which phase they are in based off of morphological cues, like the color of their shell and how the indents look next to the kind of triangular shape on their abdomen or their legs. If they are in imminent phase then there will be a grayish shadow near the legs and indents. If they are also about to molt they will be more of a dull, opaque color rather than a bright green.
Ventral View
I think
this crab might molt soon because it is dull in color and has the grayish shadow near its legs and indents around the abdomen. I would guess it is in the imminent phase.
