Project Information

Title: LTM Program: Long-term Monitoring of Humpback Whale Predation on Pacific Herring in Prince William Sound 19120114-O

Project Year and Number: 2019: 19120114-O

Other Fiscal Years and Numbers for this Project: 2024: 24120114-O, 2023: 23120114-O, 2022: 22120114-O, 2021: 21120114-O, 2020: 20120114-O, 2018: 18120114-O, 2017: 17120114-O, 2016: 16120114-N, 2015: 15120114-N, 2014: 14120114-N, 2013: 13120114-N, 2012: 12120114-N

Principal Investigator (PI): John Moran (NOAA), Jan Straley (University of Alaska Southeast)

Managing Agency: NOAA

Assisting Personnel: None

Project Website: https://gulfwatchalaska.org/monitoring/pelagic-ecosystem/humpback-whales/

Research Location: Prince William Sound

Restoration Category: Monitoring

Injured Resources Addressed: Pacific Herring

Abstract:

The humpback whale monitoring project is part of the Gulf Watch Alaska (GWA) pelagic component’s integrated predator-prey survey. Humpback whale predation has been identified as a significant source of mortality on over-wintering Pacific herring in Prince William Sound (PWS) and a likely top-down force constraining their recovery. Humpback whales in PWS have a higher percentage of herring in their diet and forage longer on herring during non-summer months than their counterparts in Southeast Alaska. Currently, North Pacific humpback whales in the Gulf of Alaska may be experiencing nutritional stress and increased use of inland waters like PWS could result in increased predation on herring. We will continue to evaluate the impact by humpback whales foraging on Pacific herring populations in PWS following protocols established during 2007/08 and 2008/09 (EVOSTC project PJ090804). Prey selection by humpback whales is determined through acoustic surveys, visual observation, scat analysis, and prey sampling. Chemical analyses of skin and blubber biopsy samples provide a longer term perspective on shifts in prey type (trophic level from stable isotopes) and quality (energy content). These data are combined in an updated bioenergetic model that allows us to assess the impact of recovering humpback whale populations on the PWS ecosystem. By integrating with the forage fish and fall/winter marine bird components, we contribute to a comprehensive understanding of bottom-up influences and top-down controls on the PWS herring population. Our project has conducted three cruises per year: a September cruise funded by GWA, and December and March cruises funded ($100K) by NOAA Alaska Fisheries Science Center. The December and March surveys during FY19-21 will no longer be funded by NOAA. Our research has demonstrated that humpback whale predation on herring peaks in the fall and spring when fish are aggregated. With the fall survey funded by GWA, we are requesting additional funding to maintain the spring cruise. A spring survey, in particular, provides an important assessment of whale abundance and predator-directed impact on pre-spawning herring schools.


Proposal: View (302 KB)

Reports:
Annual Report FY19: View (368 KB)
Final Report: See Project 21120114-O

Publications from this Project: None Available