Connecting High School Students to Research: Testing Blue Crab (Callinectes sapidus) Settlement and Educational Outcome Hypotheses
No Thumbnail Available
Files
Date
2005-11-29
Authors
Journal Title
Series/Report No.
Journal ISSN
Volume Title
Publisher
Abstract
Blue crab megalopal settlement within Pamlico Sound has shown a precipitous decline since 1999, most likely due to a 74% decline in spawning stock over that period, and a strong stock-recruit relationship (Eggleston et al. 2004). There is a critical need to continue to monitor blue crab postlarval settlement in North Carolina to identify whether or not settlement, which appears to reflect relative spawning stock biomass that same year, is improving or remaining low. There is also considerable variation in the relative abundance of postlarvae within a recruitment season, most likely due to the interaction of physical forcing mechanisms that facilitate onshore transport and the available pool of postlarvae offshore. In this study, we tested the following blue crab settlement hypothesis: H1) Mean blue crab megalopal settlement at inlet stations will be positively correlated with the number of hours of dark flood tide, maximum height of a dark flood tide event the night before sampling, and with northeasterly wind speeds. Megalopal samples were collected in Pamlico Sound, NC at four sites (Oregon Inlet, Hatteras Inlet, Manns Harbor, and Engelhard) on a daily basis from August 1 to October 31, 2003 by high school students and other paid assistants. Time series analyses identified the relationship between megalopal settlement at Oregon and Hatteras Inlets, and wind and tidal variables. No time series analyses could be conducted for settlement at Manns Harbor or Engelhard because settlement at those sites was characterized by a majority of days with no settlement and episodic peaks on a few days. At Hatteras Inlet, megalopal settlement was positively correlated with wind speeds from the northeast and southeast at lags of 0 days. At Oregon Inlet, megalopal settlement was positively correlated with wind speeds from the northeast at lags of 4 and 5 days. Tidal forcing was also important to settlement at Oregon Inlet. Blue crab megalopal settlement at Oregon Inlet was inversely related to maximum tidal height at a lag of four days. Other studies on megalopal settlement in North Carolina identified a similar relationship and suggested that this phenomena was due settlement peaks occurring around neap tides, when the number of hours of dark flood tide is high, there was; however, no relationship between the number of hours of dark flood tide and megalopal settlement at any of the sampling sites used in this study.
This study also examined the effectiveness of web-based and classroom blue crab activities on increasing student content knowledge and understanding of the nature of science. In conjunction high school students' involvement in the field portion of blue crab megalopal research, two activities were developed to illustrate some basic concepts in biology using blue crab and estuarine ecology: 1) A hands-on laboratory activity examining the morphology and behavioral characteristics of blue crabs at all life stages; and 2) A lesson incorporating a web-based simulation showing the relationship between wind direction, current flow in Pamlico Sound, and blue crab megalopal settlement at our four sampling sites. One group of high school students participated in the life cycle activity, and another group of students participated in the web-based activity. Students were given a modified version of the Views of the Nature of Science (VNOS) test both before and after participating in the activity. This test consisted of questions about the nature of science, and questions about blue crab and estuarine ecology. Scores on the blue crab ecology and nature of science portions were calculated, along with the total scores (the sum of the blue crab ecology and nature of science scores). Scores from pre- versus post-activity tests were compared to test the following hypothesis: H2) Students who participate in our blue crab educational modules will show positive educational outcomes as evidenced by significant increases in scores on the VNOS test from pre- to post-activity testing. Both groups of high school students significantly increased their test scores from pre- to post-activities on both the total scores and the blue crab ecology scores, but no increases were seen in scores on the nature of science portion of the test. This study highlights how integration of high school students and teachers into university-based research can not only provide high quality data to test research hypotheses and provide hands on research experiences for high school students, but when combined with educational activities, can increase student knowledge of the broader concepts that typically frame the research.
Description
Keywords
recruitment, megalopae, megalopa, megalops
Citation
Degree
MS
Discipline
Marine, Earth and Atmospheric Sciences
