Wet lab
The wet lab focuses on larval fish, mysid, zooplankton, and copepod sampling and identification. Samples collected in the field throughout the year are brought to the wet lab, sorted through, and later processed for organism identification. Here we also conduct otolith extraction and fish dissection. This research aids in finding San Francisco Bay tributaries that may be good spawning areas for Longfin smelt.
Otolith lab
Sample preparation
Our lab performs otolith extraction, polishing, and imaging later used for age and growth analysis. After this process, specific otoliths are chosen to be mounted on slides and analyzed for their elemental and isotopic composition in collaboration with the Center for Plasma Mass Spectrometry, University of California, Davis. This data is combined to provide valuable insights into the life histories of fishes.
Age and Growth analysis
We process fish scales, fin rays, and otoliths to generate age and growth data. State of the art laser scanning confocal microscopes are used to provide high-resolution images of otoliths, producing precise daily age estimates for larval and juvenile fishes, and precise yearly age estimates for adult fishes. Image Pro digital image analysis software is used to measure age increments for growth rate and pattern analysis. This data is combined to provide valuable insights into the age and growth patterns of fishes.
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- Wilson sanding a Delta Smelt Otolith
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- Caity processing otoliths
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- Sample boxes
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- Delta Smelt otolith
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- Sanded Longfin Smelt otolith
Analytical facilities
We collaborate directly with the UC Davis Interdisciplinary Center for Inductively-Coupled Plasma Mass Spectrometry. We specialize in laser ablation ICP-MS for quantifying trace and minor element chemistry in fish otoliths, fin rays, and scales. The center uses a New Wave Nd: Yag 213nm laser system coupled to a 7500a Agilent quadrupole ICP-MS, providing concentrations in the parts per million to parts per billion range. The New Wave laser system can provide a variety of laser configurations with a circular laser spot shape and diameters ranging from 5 to 120 microns. Typical parameters for fish otoliths are in the 20-40 diameter providing ~weekly resolution.
We are also directly involved in the development and application of laser ablation multi-collector ICP-MS to quantify isotopes of strontium in the parts-per-billion range. The use of strontium isotope ratios has distinct advantages over trace element chemistry for determining natal origins and migration histories of freshwater fishes in that chemical signatures in waters are not physiologically regulated by the fish and often directly match otolith chemistry, simplifying matching fish to natal habitats.
On the Boat
The OGFL is pursuing several projects that involve collecting data and samples from the field. We conduct monthly otter trawls surveys in the Alviso Salt Pond Restoration Area to maintain a long-term database focused on the aquatic assemblage. Recently, for the last five years, Longfin Smelt, a Californian native threatened species, has been showing up during their spawning season in our monthly trawls. This spurred its own research questions that has evolved into a broodstock collection program wherein Longfin Smelt are brought to an aquaculture facility to develop spawning technics necessary for a future (captive) broodstock population.
Early morning on the boat
Micah steering the boat
Caity pulling in the net