The Collapse of Pelagic Fishes in the Upper San Francisco Estuary: El Colapso de los Peces Pelagicos en La Cabecera Del Estuario San Francisco

Linking Hydrodynamic Complexity to Delta Smelt (Hypomesus transpacificus) Distribution in the San Francisco Estuary, USA

“…The FMWT was designed to index the year-to-year relative abundance of Striped Bass (Morone saxatilis, Stevens and Miller 1983). However, all captured species are identified and measured and the FMWT has become a long-term indicator of population trajectories for several small, pelagic fish, including Delta Smelt (Moyle et al 1992;Sommer et al 2007). Although Delta Smelt are caught westward of Suisun Bay in the spring and summer, the majority are caught east of Carquinez Strait (Bennett 2005).…”

Perils of correlating CUSUM‐transformed variables to infer ecological relationships (Breton et al. 2006; Glibert 2010)

“…The study by Breton et al (2006) is consistent with a large body of research demonstrating the importance of climate and human activity on phytoplankton communities in Belgian coastal waters (Lancelot et al 2007). However, Glibert's (2010) study piqued our curiosity about correlations between CUSUM-transformed variables because it contradicts the overwhelming weight of evidence that population collapses of native fish (Sommer et al 2007) and their supporting food webs in the San Francisco Estuary are responses to multiple stressors, including landscape change, water diversions, introductions of exotic species, and changing turbidity (Bennett and Moyle 1996;Kimmerer et al 2005;Cloern 2007;Jassby 2008;Mac Nally et al 2010;Thomson et al 2010). We ask here how CUSUM transformation leads to inferences about such cause-effect relationships when visual inspection of the data series (e.g., Fig.…”

Use of state-space population dynamics models in hypothesis testing: advantages over simple log-linear regressions for modeling survival, illustrated with application to longfin smelt (Spirinchus thaleichthys)

“…Fish and Wildlife Service also evaluated the status of the Bay-Delta longfin smelt population and concluded in 2012 that although the species warranted protection under the federal Endangered Species Act, staff limitations precluded listing the species as of that time. Several other species in the San Francisco Estuary have also experienced declines (e.g., Bennett, 2005;Sommer et al, 2007;Mac Nally et al, 2010;Thomson et al, 2010;Maunder and Deriso, 2011), but the declines have yet to be fully explained.…”