The first-ever tagging of a false killer whale with a CATs tag
Breaking new ground in marine mammal research, we were able to complete the first-ever deployment of a Customized Animal Tracking Solutions(www.cats.is; CATS)suction-cup video tag on an individual female false killer whale (Pseudorca crassidens) from the endangered main Hawaiian Islands Population.The tag remained on the animal for >12 hours and is a significant step forward in understanding more about the energetic dynamics and foraging strategies of false killer whales, and part of a long-term project on false killer whales in Hawaiʻi.
The tagger’s view for deploying the CATS suction-cup tag on the false killer whale off Maui Nui
False killer whales are found in warm and temperate waters around the world. In Hawaiʻi, there are three distinct populations: (1) the Northwestern Hawaiian Islands population, (2) the pelagic population, and (3) the endangered main Hawaiian Islands insular population, which is the focus for this project.
In Hawaiʻi, false killer whales are known to interact with the Hawaiʻi Longline Fishery (HLF) and efforts to mitigate these interactions are informed by the False Killer Whale Take Reduction Team (TRT). The TRT is an advisory group tasked with developing strategies to reduce the mortality and serious injury of false killer whales associated with interactions with the HLF. However, current recommendations available to minimize interactions are difficult and economically challenging. To better guide future mitigation strategies for false killer whales will require a stronger understanding of the possible population-level impacts of interactions, as well as detailed information on foraging strategies during depredation events. This project jointly led by PWF and the MMRP provides a novel and cost-effective approach to address research priorities identified by the TRT using newly available technologies and methods to:
Determine the fine-scale behavior (via on-animal video recording and, tag accelerometer data) associated with foraging and prey-handling to guide innovative strategies for mitigating depredation and hooking events.
Determine the relationship between observed injuries and individual health (i.e., body condition) to explore the impacts of injuries on long-term survival and resultant population recovery.
Expand our understanding of this species’ acoustic behavior, in particular during prey handling, and provide acoustic cue rates for this species to better inform PAM efforts in the Hawaiian region.
By enhancing our understanding of false killer whale's prey capture and handling techniques, as well as the long-term implications of injuries on their health and survivorship, this project will provide crucial information to the TRT in achieving their goal of reducing mortality and serious injury associated with depredation.
The CATs suction-cup tag being attached to the false killer whale off Maui Nui from R/V Ocean Insight
CATS tags are cutting-edge technology that allows us to attach cameras and sensors to marine mammals, such as whales and dolphins. They are non-invasive, meaning they are attached to the animal without causing harm via suction-cups, and are designed for short-term deployments and usually fall off after 8-12 hours. One of the key advantages of CATS tags is their ability to collect continuous fine-scale three-dimensional movement data, such as their swimming speed, direction, and body orientation using a range of sensors. This can then be coupled with acoustic recordings through an onboard hydrophone, and video via the embedded high-resolution camera, which when combined allows us to piece together exactly what the animal did throughout the deployment. For example, from last month's deployment we can determine the following:
Precise tracking of its travel, diving, socializing, and foraging activities down to the second.
Analysis of the frequency and intensity of its various vocalizations, correlated with visual observations.
Documentation of the number and speed of each fluke beat correlated with visual observations.
Examination of changes in behavior and movement patterns from day to night and throughout the deployment period.
Accurate measurement of its depth throughout the deployment, linked to behavior, movement, and video observations.
Study of its socialization behaviors and interactions with both false killer whales and other species.
Quantification of the energy expended during travel (informed via ventilation rates) and energy gained through feeding activities.
Collecting CATS tags after they fall off is a crucial final step in retrieving the valuable data stored on the tag and is often the most stressful part. After our tag fell off North of Molokaʻi, we followed it for two days, via the ARGOS website, in hopes it would drift closer to shore. However, with a clear NW trajectory soon putting the tag beyond retrieval distances, we decided to charter a 75-foot sports fisher and embark on a retrieval journey that would take us 40 nautical miles north of Oahu.
Map showing the location of deployment (tag on), when it fell off (tag off), and was finally retrieved.
Despite facing strong winds and enduring a 16-hour trip that began before sunrise and ended after sunset, our team successfully retrieved the tag.
The tag retrieval team celebrating after having found the tag 40 nautical miles North of Oahu.
This research is a pivotal component of an ongoing collaborative effort between the Marine Mammal Research Program and Pacific Whale Foundation, with the ultimate objective of utilizing cutting-edge technology, including suction-cup CATs tags and unoccupied aerial systems (UAS; drone), to gain new insights into the odontocete populations in Hawaiʻi. The findings from this research will provide new perspectives on the following and will facilitate the development of updated conservation and management strategies, to ensure the long-term preservation of whales and dolphins in Hawaiʻi. This ongoing research is made possible with funds from the National Marine Fisheries Service, Marine Mammal Research Program, and Pacific Whale Foundation. All research activities conducted under NMFS/MMPA research permit #21321/21476.
Will and Jens, who have been part of the false killer whale tagging team since 2020, celebrate their first successful deployment.