On simulating cold stunned turtle strandings on Cape Cod

Kemp’s ridley turtles were on the verge of extinction in the 1960s. While they have slowly recovered, they are still endangered. In the last few years, the number of strandings on Cape Cod Massachusetts beaches has increased by nearly an order of magnitude relative to preceding decades. This study uses a combination of ocean observations and a well-respected ocean model to investigate the causes and transport of cold-stunned animals in Cape Cod Bay. After validating the model using satellite-tracked drifters and local temperature moorings, ocean currents were examined in the Cape Cod Bay in an attempt to explain stranding locations as observed by volunteers and, for some years, backtracking was conducted to examine the potential source regions. The general finding, as expected, is that sub 10.5°C water temperatures in combination with persistent strong wind stress (>0.4Pa) will result in increased strandings along particular sections of the coast dependent on the wind direction. However, it is still uncertain where in the water column the majority of cold stunned turtles reside and, if many of them are on the surface, considerable more work will need to be done to incorporate the direct effects of wind and waves on the advective processes.

Objective classification of North Atlantic right whale (Eubalaena glacialis) vocalizations to improve passive acoustic detection

Passive acoustic monitoring is playing an increasing role in the detection of endangered North Atlantic right whales (NARW). Previous acoustic monitoring has relied on a single stereotyped vocalization, the upcall. Here the entire repertoire produced by NARW during the winter and early spring in Cape Cod Bay, Massachusetts is described. An objective sound classification scheme and automatic classification algorithm were developed. Nine days of acoustic recordings were used for the data analysis and a total of 9,611 right whale sounds were identified. The objective classification scheme of right whale sounds allowed for rapid identification of a diversity of right whale sounds. These sounds were assigned to 6 classes of narrowband upcalls, downsweep, complex and high frequency calls, wideband gunshot sounds and complex sounds. Results indicate that the prevalence of upcalls varied from 28% of detected calls in January to 80% in April. Other classes of signals were also well represented in the repertoire including the narrowband complex(10-36%) and high frequency calls (1-26%), wideband gunshot sounds (4-25%) and wideband complex sounds (0 – 25%). The prevalence of non-upcall signals suggests that including more signals classes may improve rates of detection for right whales in the Cape Cod Bay habitat.

Objective classification of North Atlantic right whale (Eubalaena glacialis) vocalizations to improve passive acoustic detection

Passive acoustic monitoring is playing an increasing role in the detection of endangered North Atlantic right whales (NARW). Previous acoustic monitoring has relied on a single stereotyped vocalization, the upcall. Here the entire repertoire produced by NARW during the winter and early spring in Cape Cod Bay, Massachusetts is described. An objective sound classification scheme and automatic classification algorithm were developed. Nine days of acoustic recordings were used for the data analysis and a total of 9,611 right whale sounds were identified. The objective classification scheme of right whale sounds allowed for rapid identification of a diversity of right whale sounds. These sounds were assigned to 6 classes of narrowband upcalls, downsweep, complex and high frequency calls, wideband gunshot sounds and complex sounds. Results indicate that the prevalence of upcalls varied from 28% of detected calls in January to 80% in April. Other classes of signals were also well represented in the repertoire including the narrowband complex(10-36%) and high frequency calls (1-26%), wideband gunshot sounds (4-25%) and wideband complex sounds (0 – 25%). The prevalence of non-upcall signals suggests that including more signals classes may improve rates of detection for right whales in the Cape Cod Bay habitat.