Abstract
This study is a preliminary approach to understand the overlapping distribution of long- finned and short-finned pilot whales and to determine if the Gulf Stream and its environmental parameters such as salinity, temperature, and depth influence pilot whale activity. Acoustic recordings were taken from three, landers, which were platforms equipped with a variety of sensors and instruments that were submerged and deployed to the bottom of the ocean and used to collect data. Geographic Information Systems tools were used to determine the call distribution and presence of the Gulf Stream and to conduct Ordinary Least Squares (OLS) regressions for the call activity collectively and within individual months. Call distribution refers to the extent and grouping of pilot whale calls across the three locations in the four months of this study. Raven lite was utilized to measure the frequency range and duration of the downloaded calls and determine if they were from a short-finned or long-finned pilot whale. The Virginia Inter-Canyon (VAC) lander, which was situated on the cold wall of the Gulf Stream, recorded most of the pilot whale calls (n=4500) The Blake Escarpment (BLE) lander however, in February of 2019, recorded most of the calls for the short-finned pilot whales. An unknown noise classified as a pilot whale call but sounding like a screech was recorded at all three locations. The most “screeches” were recorded at the Charleston Bump (CHB) lander, but the most screeches in a single month were found at the BLE lander in February 2019. The OLS regressions showed that salinity had the strongest relationship to the call activity indicating that salinity may have had a high influence on the number of calls in an hour. Results show that long- finned and short-finned pilot whales were present in all three locations, but most short-finned pilot whale calls came from the CHB and BLE landers. These results suggest that the long-finned pilot whales may travel farther south than originally thought. The source of the screech cannot be determined but the signal characteristics are like man-made sonar systems. This is an important area of future research as sonar can adversely affect pilot whales and other marine mammals. These results can be used for a more refined distribution study for each specific species and towards conservation efforts focusing on overlap in pilot whale habitat and anthropogenic activities including fishing and naval activity.