January 1, 2016.
The San Francisco Estuary is a complex ecosystem. A key part of the foodweb are zooplankton crustaceans, specifically copepods. Many fish, especially the endangered delta smelt, rely on copepods as a food source. Measuring the growth of copepods assists in predictions if enough food is available for delta smelt. Traditionally growth rate is measured through lengthy and involved processes. The objective of this research project is to develop an imaging process to analyze biomass of copepods more efficiently. For this research, field samples of copepods were collected and grown over three days. Subsamples were taken and preserved at three predetermined time frames during their growth. Subsamples were imaged on a microscope and measurements were taken using an automated protocol developed using ImageJ scientific imaging freeware. Since copepods are roughly the shape of an ellipsoid, measurements of the major and minor axes of the copepods were used to calculate volumes of their ellipsoid shapes. Results of volumes showed that there is usually a 30%-38% increase in volume growth each day. There is also lower uncertainty in this data than found using past growth rate methods. Future use of this data will be compared to actual carbon masses to create a ratio to determine biomass in relation of volume measurements taken from images. This will assist in predicting abundance of copepod biomass in the San Francisco Estuary and the impact on the food web.
Aquaculture and Fisheries | Zoology
Wim Kimmerer, Toni Ignoffo
Romberg Tiburon Center for Environmental Studies (RTC)
*This project has been made possible with support from the National Marine Sanctuary Foundation (www.marinesanctuary.org) and the California State University STEM Teacher Researcher Program