Gianna, Jack, Peter, and Nathan
Bishop O’Dowd High School
After going on a trip to Ocean Beach in San Francisco and gathering data about the local sand crabs, we wondered how many of them were “recruits,” little crabs which are new to life on the beach. How does this number change over time? Once a recruit settles on a beach, it will spend the rest of its life there. So, a healthy recruit population means that there will be a healthy adult population in the future (unless there is an environmental hazard). As long as there are no environmental hazards or strange weather conditions, the portion of recruits can be used to predict future sand crab growth and decline.
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