Whale tales and seabird sentinels: increased abundance in a productive year


Farallon Institute scientists participated in the 2018 Juvenile Rockfish Ecosystem Survey (JRES) cruise, an annual mid-water trawl survey that assesses young-of-the-year fish stocks throughout California waters over a 5-week period. These cruises also provide an opportunity to collect data on marine predators such as sea birds and marine mammals, which are conspicuous indicators of ecosystem health and stability. During the 2018 JRES cruise, seabird surveys were conducted on board the NOAA vessel R/V Reuben Lasker, and documented the highest encounter rate of humpback and fin whales observed yet over a 23-year period. Humpback and fin whale sightings were especially common in outer Monterey Bay, Halfmoon Bay, and the Gulf of the Farallones, reflecting the cool water, strong upwelling, and increased biological productivity this year. In comparison, seabirds sightings also increased in 2018, yet none of these increases were significantly greater than the normal range of interannual variation. Even in a productive year, we continue to see the hallmarks of a complex ecosystem: unpredictable species responses to a dynamic environment!