The Pacific Sardine
In our first installment in a series of fisheries “classics” we discuss the Pacific sardine (Sardinops sagax). The US west coast sardine fishery made headlines last year when the Pacific Fishery Management Council completely closed the commercial fishing seasons for Washington, Oregon and California. The sardine fishery has been quite important in understanding the biology of exploited fishes and is justly deserving of being our first “classic” fisheries story.
History of abundance, catch and fishing mortality
Pacific sardines once supported the largest fishery in the California current, off the west coast of North America from Canada to Baja California. The fishery developed at the beginning of the Great Depression as Pacific sardines were processed for food and oil as well as for fish meal used by the expanding poultry industry. At its peak, the fishery yielded 600,000mt annually (MacCall 2015). Cannery Row, in Monterey, CA (made famous by John Steinbeck’s novel of the same name) was named for the sardine processors that lined the main street.
In the 1950s, the stock collapsed—culminating in a California-legislated moratorium on commercial sardine harvests from 1967-1986, closing even the small bait fishery (Figure 1). This collapse initiated the first assertions from the scientific community that overfishing was the root cause of the problem (MacCall 2011). By 1972 fishing effort in the California current had shifted to northern anchovies (Engraulis mordax), which had become abundant.
Through the 1980’s and 1990’s Pacific sardine abundance began to recover. This period was marked by a notable El Niño year in 1992 when Pacific sardines were dispersed as far north as British Columbia where they had not been seen in over 40 years (MacCall 2015). In the early 2000’s Pacific sardine biomass levels reached 1 million mt, but with a series of poor recruitments declined to the low levels reported last year.
See Figures 2, 3, 4a and 4b for biomass, catch and total allowable catch (TAC), and fishing mortality rate of Pacific sardines.
History of science, management and fishing fleet
During most of the 20th century, the Pacific sardine fishery was managed by the California Department of Fish and Game (CDFG). In response to the puzzling scientific issues raised by the 1950’s collapse, the fishing industry adopted a self-imposed tax and underwrote the creation of a new multiagency scientific program, the California Cooperative Oceanic Fisheries Investigations (CalCOFI), an entity that still exists today. When the Pacific Fishery Management Council (PFMC) was formed in the late 1970’s, sardines were scarce, and the PFMC declined responsibility for managing a nonexistent fishery. With the subsequent re-growth of the stock and reappearance of fishable concentrations off Washington in the 1990’s, the PFMC assumed control of the US fishery under the authority ofr the Maguson-Stevens Act. . Federally mandated TAC guidelines from the PFMC began in 2000 (Figure 3). CalCOFI has remained an important engine for Pacific sardine research, but NMFS assumed responsibility for annual stock assessments needed by the PFMC.
In the US, the Pacific sardine is currently a limited entry fishery with a total allowable catch (quotas), however the limited entry permit covers all pelagic finfish, not just sardines. There are 65 permit holders, but it is unclear how many boats target which species (PFMC 2011). Sardines are typically caught with purse seines, though some vessels are transitioning to drum seines (PFMC 2011). The historical hubs are still in Southern California and Monterey Bay, but Astoria has recently supported a major fishery. About 85% of the catch is processed and shipped to China, Japan and South Korea (CAOPC 2013). The other 15% typically composes the bait fishery. Bycatch is negligible (less than 1%), though there may be impacts on California sea lions that have come to rely on sardines as an important food source (Hill et al. 2015).
In 1965 Garth Murphy conducted a comprehensive study of sardine demography in the California current and concluded that intense fishing effort was the primary cause for the stock’s collapse (MacCall 2011). It was precipitated by poor recruitment in the early 1950’s, but overfishing was considered the main catalyst. Murphy also suggested that the surging populations of northern anchovy had ecologically replaced Pacific sardines (MacCall 2011). Specific environmental influences were not identified.
The overfishing paradigm was not comprehensively challenged until 1992 when Soutar and Isaacs (1972) conducted a fish-scale analysis from anaerobic sediment deposits off the coast of Santa Barbara, and found that sardines had naturally disappeared at other times in the past. More detailed analyses by Baumgartner et al (1992) showed a somewhat cyclical pattern for Pacific sardine populations with periods of roughly 50 years (Figure 5) (Baumgartner et al. 1992; Chavez et al. 2003); although other analysts argue 100 years to be a more representative cycle period (Gamble et al 2003). The cause of these cycles, whether they be 50 or 100 year periods is unclear. The predominant theory is that the productivity changes are due to upwelling cycles and/or changes in oceanic circulation associated with long-term fluctuations in sea surface temperature (CAOPC 2013; MacCall 2015).
While populations did increase according to Baumgartner et al’s 50-year theory in the 1990’s, they were still well below the high levels of the 1940’s. Similar to patterns of fluctuations seen in the Santa Barbara sediments, Pacific sardine biomass dropped sharply from 1 million mt in 2006 to an estimated 97,000 mt in 2015, causing the abrupt closing of the commercial fishery, in accordance with the biomass-dependent harvest plan
Baumgartner, T. R., A. Soutar, and V. Ferreira-Bartrina. 1992. Reconstruction of the history of Pacific sardine and Northern anchovy populations over the past two millenia from sediments of the Santa Barbara Basin, California. CalCOFI Reports 33:24–40.
Chavez, F. P., J. Ryan, S. E. Lluch-Cota, and M. Niquen C. 2003. From Anchovies to Sardines and Back: Multidecadal Change in the Pacific Ocean. Science 299(5604):217–221.
California Ocean Protection Council (CAOPC) 2013. Rapid Assessments for Selected California Fisheries. California Ocean Science Trust. Oakland, California, USA.
Gamble, E. D., J. Issacs, A. Soutar, P. Crill. 2003. Sardine cycles longer than fifty years. Science E-Letters. Response to Chavez et al.
Hill, K. T., P.R. Crone, E. Dorval, B.J. Macewicz. 2015. Assessment of the Pacific Sardine Resource in 2015 for USA Management in 2015–16. National Marine Fisheries Council.
MacCall, Alec D. Personal Interview. 20 October 2015.
MacCall, Alec D. “The sardine-anchovy puzzle.” Shifting Baselines. Island Press/Center for Resource Economics, 2011. 47–57.
Pacific Fishery Management Council (PFMC) 2011. Coastal Pelagic Species Fishery Management Plan.
“South American Pilchard—Northern (cold) Stock: Fish Source Scores.” Fish Source. Sustainable Fisheries Partnership, 2016. Web.