Fish Cliques: Evidence of Social Groups from Sparse Observations in Time and Space?

Presented at Joint Statistical Meetings, 2 August 2016, Chicago, IL.

1. Fish Cliques: Evidence of Social Groups from Sparse Observations in Time and Space ? USGS - Great Lakes Science Center Jean Adams, Stephen Riley, Taaja Tucker Michigan State University Charles Krueger, Thomas Binder
2. In Lake Huron, 60,000 detections of 250 tagged fish at 30 stations Lake Trout
3. Same station: 4 days Both observed: 7 days Together: 4 / 7 = 57% Unique stations: 3 Detections for one pair of fish
4. • Hypotheses • H0 : seasonal movement patterns • HA : synchronized "group movement" • Identify groups that move together • together > 50% 11 pairs of fish • > 2 unique stations 17 individuals Detections for all pairs of fish
5. observed • Randomization • Add time shift from -3 to +3 days to each fish • Identify groups • repeat 100 times • mean no. fish in groups: 10.7 (7, 18) • Groups we observed are what we would expect by chance • No evidence of "fish cliques"