Delta Smelt Markings Study One of Many USFWS Highlights at 2016 Bay Delta Science Conference

SACRAMENTO (Nov. 15, 2016) – The feasibility of using natural external marks such as spots and scars to better study cultured Delta Smelt will be the basis of U.S. Fish and Wildlife Service biologist Gonzalo Castillo’s presentation at the 2016 Bay Delta Science Conference that began today. The conference runs Thursday, November 17.

Castillo’s presentation, “Identification of Individual Cultured Delta Smelt Using Visual and Automated Analysis of Natural Marks,” is one of several featuring USFWS scientists over the conference’s three days (full list below). The popular bi-annual conference provides a forum for presenting technical analyses and results related to the Delta Science Program and to provide new information to the broad community of scientists, engineers, resource managers, and stakeholders working on Bay-Delta issues.

The conference’s full agenda and other information can be found at http://scienceconf2016.deltacouncil.ca.gov/

In cooperation with the UC Davis Fish Conservation and Culture Lab, and the U.S. Bureau of Reclamation, Castillo will present the preliminary results on the feasibility of using external natural marks to identify cultured Delta Smelt. This is the first study that evaluated the use of non-artificial marks to identify individual cultured Delta Smelt, Castillo said.

For the study, researchers selected the dorsal head area of Delta Smelt, where external pigmentation is particularly abundant. To verify the usefulness of natural marks, each fish in the study was tagged with a unique alpha numeric tag in 2013-2015 and then each digital image not showing the artificial tag was randomly named and evaluated as a unique natural mark to the naked eye and then by an automated image recognition program.

“While the usefulness of natural marks remains to be demonstrated in wild Delta Smelt, the method could be used to improve our understanding of Delta Smelt behavior, residence and movement in different areas of the Delta,” Castillo said. “Ultimately, this information could be used to refine life cycle models and improve management of the species.”

Researchers also plan to conduct a preliminary evaluation of natural marks on wild adult Delta Smelt collected and photographed by Lodi Fish and Wildlife Office staff during upcoming fisheries monitoring surveys.

In addition, new USFWS Regional Director Paul Souza will be part of a discussion panel on Wednesday, 10:20 a.m., addressing threatened and endangered species, The panel will explore communicating complex science for decision-making by featuring discussions between authors of chapters in "The State of Bay-Delta Science 2016" and the policymakers grappling with decisions related to the author's chapters.

Other USFWS participants at the conference include:

Committee member Leanna Zweig, who is also chairing the Biology, Ecology and Management of Central Valley Salmonids session, Wednesday, 10:20 a.m.; Steve Culberson, chairing the Food Web Foundations session, Tuesday Nov. 15, 1:35 p.m.; Cesar Blanco, presenting “The ARM of the Central Valley Project Improvement Act,” Tuesday, Nov. 15, 3:35 p.m.; Lori Smith, presenting “Larval Fish Assemblage Structure and Prey Availability in Liberty Island,” Tuesday, Nov. 15, at 4:35 p.m.;

Patricia Brandes, presenting “Timing of Hatchery and Wild Winter-run Chinook Salmon Caught in the Sacramento River and Chipps Island Trawls for the Implementation of Delta Management Actions,” Wednesday, Nov. 16, 10:20 a.m.; William Beckon, presenting “How Long Does it Take for Selenium to Bioaccumulate in the Diet and tissues of Sturgeon,” Wednesday, Nov. 16, at 1:35 p.m.; Laura Heironimus, presenting “Fish on the Edge: Assessing Environmental Constraints for Recruitment of White Sturgeon in the San Joaquin River,” Wednesday, Nov. 16, 2:35 p.m.; Leo Polansky, presenting “A Life Cycle Model and Population Viability Analysis for Wild Delta Smelt,” Wednesda, Nov. 16, 2:35 p.m.; William Smith, presenting “A Delta Smelt Life Cycle Model: Separating Entrainment from Other Sources of Mortality,” Wednesday, Nov. 16, 2:55 p.m.; Ken Newman, presenting “A Road Map for Designing and Implementing a Biological Monitoring Program,” Wednesday, Nov. 16, 4:55 p.m.;

Poster presenters include Louanne McMartin, with “Invasive Watersnake Poses Threat to California Native Species;” Ronald Smith, “Occurrence of Large-Scale Loach in the Sacramento-San Joaquin Basin;” Denise Barnard, “2016 South Delta Chinook Salmon Survival Tag Retention Study, Increased Tag Burden Results in Increased Tag Expulsion;” and Meg Marriott, “Climate Change Adaptions in a North Bay Centennial Marsh.