Meeting Abstract
30.4 Friday, Jan. 4 Reproductive State Influence on Female Bottlenose Dolphin Ranging Patterns GIBSON, Q.*; HOWELLS, E.; LAMBERT, J.; MAZZOIL, M.; O’CORY-CROWE, G.; RICHMOND, J.; University of North Florida; Harbor Branch Oceanographic Institute; University of North Florida; Harbor Branch Oceanographic Institute; Harbor Branch Oceanographic Institute; University of North Florida quincy.gibson@unf.edu
Variation in mammalian home range patterns is often linked to energetic requirements, which likely differ depending on reproductive status. Yet, few studies have tested whether bottlenose dolphins (Tursiops truncatus) adjust their ranging patterns with respect to reproductive status. Using data from Indian River Lagoon, Florida (1997-2007), we compared the ranging patterns of nursing and non-nursing adult females with both longitudinal and cross-sectional analyses. The size of females’ home ranges (HR) and core areas (CA) were not significantly different between reproductive states (P>0.05), presumably due to a lack of directional pattern among females. HR size varied greatly among individual females, 9.4–90.8km2 nursing versus 20.9–186.1km2 non-nursing. CA size ranged from 0.4–56.7km2 nursing and 0.4–49.7km2 non-nursing. Overlap between nursing and non-nursing ranges also varied greatly among individuals (HR: 13.9–95.0%, CA: 0–94.0%). Nursing females continued to utilize 52.0±5.1% of their non-nursing HR but only 19.1±5.45% of their non-nursing CA. In our cross-sectional analysis, a large portion (77.75±5.41%) of the non-nursing 95% utilization distribution was also used by nursing females across all seasons. However, overlap between nursing and non-nursing 50% utilization distributions was low (< 35%) in all seasons except summer. These findings suggest that variation in ranging patterns among individual females was greater than by reproductive state. Females continued to use a large proportion of their overall range, but concentrated in different areas depending on their reproductive status.
