Dear MARMAM community,

On behalf of my co-authors, we are pleased to share our recent paper in Aquatic 
Conservation.


Markowitz, T. M., Keener, W., Webber, M. A., Payne, A. R., Lane, R. S., 
Fahlbusch, J. A., & Calambokidis, J. (2024). New urban habitat for endangered 
humpback whales: San Francisco Bay. Aquatic Conservation: Marine and Freshwater 
Ecosystems, 34(3), e4107.


The open access article is available at: https://doi.org/10.1002/aqc.4107


Abstract: As populations of large whales recover from whaling, species that 
forage and breed in coastal waters, including the humpback whale (Megaptera 
novaeangliae), increasingly overlap with human activities. This represents a 
potential hazard in locations worldwide subject to intensive vessel traffic, 
including New York, Panama City and Brisbane. Historically, humpback whales 
were not considered part of San Francisco Bay's fauna, except for a few ‘lost’ 
whales that wandered into the estuary. An unprecedented influx of humpback 
whales into highly urbanized San Francisco Bay began in 2016. Research efforts 
in 2016–2018 from vessels and shore resulted in 496 photo-identification 
records plus 319 visual sightings. Sixty-one individuals were photo-identified, 
of which 80% (n = 49) used the bay on multiple days (range = 2 to 39), and 34% 
(n = 21) were resighted in successive years. Whales photographed in San 
Francisco Bay were found to belong to distinct population segments listed as 
endangered and threatened under the U.S. Endangered Species Act. Whales moved 
in and out of the bay seasonally (April–November). Habitat use patterns 
indicated movements farther into San Francisco Bay correlated positively with 
high tides. Humpback whales were visually observed lunge feeding on northern 
anchovy (Engraulis mordax) at the surface. Analysis of dive patterns by three 
tagged whales confirmed subsurface feeding when surface feeding was not 
apparent. The use of San Francisco Bay and adjacent waters by recovering 
populations of humpback whales exacerbates the potential for collisions with 
vessels, entanglement in fishing gear, and harassment by recreational vessels. 
The most pressing conservation concern is the risk of ship strikes, observed 
where humpback whales occur near active seaports.



Bill Keener

Research Biologist

Cetacean Conservation Biology

keen...@tmmc.org<http://www.marinemammalcenter.org/> | C: 415.297.6139 | 
MarineMammalCenter.org<http://www.marinemammalcenter.org/>

The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965

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