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Full-Text Articles in Life Sciences
Zooplankton Trophic Ecology In The San Francisco Estuary During Summer As Determined By Stable Isotope Analysis, Kyla Bradylong, Steven Westbrook, Julien Moderan, Wim Kimmerer
Zooplankton Trophic Ecology In The San Francisco Estuary During Summer As Determined By Stable Isotope Analysis, Kyla Bradylong, Steven Westbrook, Julien Moderan, Wim Kimmerer
STAR Program Research Presentations
Declines in the abundance of several pelagic fish species in the upper San Francisco Estuary have prompted investigation into food web interactions within the estuary and delta (the lower Sacramento and San Joaquin Rivers). This area is characterized by low primary production and pelagic food webs much longer and reticulated than previously thought, implying low efficiency in the energy transfers from primary producers to planktivorous fish. We determined the carbon and nitrogen stable isotope (SI) composition of zooplankton samples collected monthly between June 2012 and February 2013 at eight stations along the salinity gradient. As consumers SI composition reflects that …
Jellyfish Identification And Quantification In The San Francisco Estuary, Amalia Borson, Lindsay L. Sullivan, Wim Kimmerer
Jellyfish Identification And Quantification In The San Francisco Estuary, Amalia Borson, Lindsay L. Sullivan, Wim Kimmerer
STAR Program Research Presentations
As potential predators and competitors of plankton-eating fish, jellyfish have the potential to negatively impact fish populations. Jellyfish were collected weekly with plankton tows from the RombergTiburonCenterpier in Tiburon, CA. Since some jellyfish were too small to identify, one tow was collected and preserved to record abundances, and a second tow was collected to rear jellyfish until distinguishing characteristics were visible enough for identification. Jellyfish in the preserved tows were then identified, measured, and counted, and their abundance (number m-3) was calculated. Jellyfish from the second tows were reared in plastic buckets that were lightly bubbled using aquarium …
Feeding Ecology Of Delta Smelt During A Seasonal Pulse Of Turbidity, William A. Hilton, Aaron Johnson, Wim Kimmerer
Feeding Ecology Of Delta Smelt During A Seasonal Pulse Of Turbidity, William A. Hilton, Aaron Johnson, Wim Kimmerer
STAR Program Research Presentations
The delta smelt (Hypomesus transpacificus) is a small, pelagic fish endemic to the San Francisco Estuary (SFE) and protected under federal and state endangered species acts. This study examines the diet of adult delta smelt during their spawning migration in the winters of 2010 and 2012. Delta smelt and their zooplankton prey were sampled concurrently during a seasonal pulse of turbidity at sites along their migratory route from the low salinity zone in Suisun Bay to the fresher waters of the Sacramento/San Joaquin Delta. Gut contents were identified to the lowest possible taxon and counted, along with zooplankton …