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| Some of our campers exploring the intertidal zone |
My favorite creature of the week was the horseshoe crabs, we found two this week! On Tuesday one of our campers was walking in the water, about up to her shin, and found a very large female crab. Then on Wednesday, we found another at about the same depth. This one, however, was a male and significantly smaller than the first. Many of our campers and some of the staff had never seen one. I enjoyed teaching everyone what I knew about them. My favorite thing to teach students is how to identify if they are male or female. If you flip the horseshoe crabs over and look at their front pair of legs, it looks like boxing gloves if they are male and split like a peace sign if they are female. My two favorite fun facts about horseshoe crabs are that they are more closely related to spiders than crabs and that their blood is used to detect harmful bacteria in medicines or on equipment. This dramatically impacted their population for a while, but they are being harvested less for their blood today because an alternative way to perform the same test has been discovered. The timing of this discovery is important because horseshoe crab populations have been declining due to habitat loss and overharvesting. Horseshoe crabs don’t have pinchers and if handled with care you can hold and touch them! You can read more about them on the US Fish and Wildlife website here.
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| Holding the smaller male horseshoe crab that we found |
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| The awesome team I work with, holding the first horseshoe crab we found. Left to right: Aiden, Damani, Che, and Maggie |
We also caught many green crabs this week. We set out a crab trap daily and caught around 90 crabs Monday through Wednesday. Green crabs are a very interesting species to learn about, but it is actually a bad sign that we found so many. They are an invasive species that take resources that would otherwise be available to native crab species. Native species are defined as organisms that naturally occurred in an area before European settlement. Non-native species would be any that were accidentally or intentionally brought to an area by human influences. Invasive species are a subgroup of non-native species that specifically disrupt native species or whole ecosystems. Green crabs were unintentionally brought over to the United States, likely from ships. They are harmful for several reasons, which can be summarized by the fact that they are effective predators. Fisherfolk are particularly impacted because green crabs often eat soft-shelled clams and compete with lobster and native crabs for food. This, in turn, lowers the population of these other organisms and makes them harder for fisherfolk to find. There is research underway to study the feasibility of a green crab fishery in hopes that this could help curb the population growth. We can help to prevent the spread of green crabs and other invasive species by making sure we don't transport water, wood, or seeds from one ecosystem to another.
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| After catching many green crabs in our crab trap we released them and had a "crab race" to see which would make it to the water first. |
This has been a great week; I feel that I am constantly impressed with our staff, the campers, and nature all around us. The college and high school staff on my team have been wonderful, always jumping in to help and great with our campers. I have also been awed by the number of cool creatures we have found, and can’t wait for a full week out on the water!
Until next week,
Tessa
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