Project H.8.c - Cow-calf separation study
Program(s) in charge: Stock Assessment Program
Click to see projects by theme, goal or target:
- Theme 3. Sustainable fisheries
- Evaluate whether permanent separation of dolphin mothers and their calves occurs during purse-seine fishing operations on dolphin-associated tuna.
- With the drastic decrease in dolphin mortality due to entanglement in tuna purse-seine nets during the 1990s, more attention was paid to other possible sources of mortality.
- Some studies have shown that in the 1980s and 1990s there were cases of orphaned nursing calves due to maternal mortality.
- Based on analysis of biological samples collected by fisheries observers, it has also been suggested that mothers and calves may be separated during chases leading to purse-seine sets.
- However, it remains an open question whether current fishing operations lead to permanent separation of cows and calves.
- The objective of this study is to resolve this question by determining, through direct observation, whether dolphin mothers and calves are indeed separated during chase and/or backdown.
- Relevance for management
- Improve the management of dolphin stocks in the ETP.
- 12 months
- Workplan and status
- May 2022: obtain commitment from one or more purse-seiners to participate in the study.
- June – August 2022: hold workshop on development of a detailed field protocol; consultation with drone team on project details; hire graduate students and an observer to assist with project.
- September – November 2022: preparation for study.
- December 2022 – January 2023: Conduct field study.
- January – May 2023: data analysis; report preparation.
- External collaborators
- Michael Scott;
- Workshop participants: Drs. Karin Forney and Eric Archer (NMFS); Drs. Lisa Balance and John Durban (Oregon State University).
- Drone company; several graduate students, one or more purse-seine vessels.
- Pacific Alliance for Sustainable Tuna
- Presentation of results at SAC-14 (May 2023).