Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
STOCKTON FWO: Breach III - Sampling and Monitoring the Response of Macro-invertebrates and Fishes to Restoration at Liberty Island.
California-Nevada Offices , February 6, 2012
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Fyke net retrieval
Fyke net retrieval - Photo Credit: USFWS
Gill Net Deployment
Gill Net Deployment - Photo Credit: USFWS

By Lori Smith, Stockton FWO

In 2009, the Stockton Fish and Wildlife Office (STFWO) served a critical role in developing and facilitating a collaborative interdisciplinary study known as Breach III to assess the effects of restoration on aquatic biota inhabiting the tidally influenced freshwater wetlands at Liberty Island and Little Holland Tract in Yolo County, California. The goals of the Breach III project are to provide a predictive level of understanding about (1) how restoration activities influence local flooding and levee erosion and (2) how abiotic and biotic factors control aquatic vegetation, fish, and wildlife distributions.

From February 6 – 10, 2012, the STFWO’s Delta Juvenile Fish Monitoring Program (DJFMP) collaborated with the University of Washington (UW) and Washington State University (WSU) to simultaneously address the macro-invertebrate and nekton response portions of the study at Liberty Island during the last of three hydrologic sampling periods. The Service assisted the Universities by providing two boats and three personnel to facilitate sampling.

The nekton sampling, led by the WSU, was designed to evaluate the use of a restoring wetland by specific life stages of delta smelt, longfin smelt, Chinook salmon, striped bass, threadfin shad, and Sacramento splittail. Adult and juvenile fishes were sampled using gill and fyke nets at six locations to monitor both the abundance and diet of fishes. In addition, the DJFMP sampled larval fishes using trawls to monitor larval fish abundance throughout Liberty Island. The macro-invertebrate sampling, led by the UW, was designed to identify and monitor assemblages associated with the spatial and temporal development of the restoring wetland with emphasis on prey taxa of priority fishes. The UW took benthic core samples, conducted zooplankton trawls, and deployed insect fall-out traps to monitor the abundance of macro-invertebrates under the substrate, within the water column, and on the water’s surface, respectively.

Now that the macro-invertebrate and nekton sampling component of the agreement has concluded, DJFMP is working with the universities on the analysis and synthesis of the data collected during the three hydrologic periods. The preliminary data and findings are slated to be presented at the 2012 Bay Delta Science Conference at the Sacramento Convention Center in Sacramento, California, October 16-18. The final results from the nekton response and macro-invertebrate monitoring will be used in a model for predicting the ecological responses to change in habitat structure as a restoring system passes through the vegetation re-colonization threshold and continues to expand into a predominantly vegetated wetland landscape. Upon completion of the Breach III study in June 2013, the results from the entire study will be published in a final report to the California Department of Fish and Game as per the CALFed funded Breach III agreement.


Contact Info: Lori Smith, 209-946-6400 x343, lori_smith@fws.gov
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