This is from the Daily Democrat, and reminds us of the important work being done by UC Davis.
A team of researchers is waiting to learn how many of the small chinook salmon that were raised on the healthiest of food in Mike Dewit’s rice field in the Yolo Bypass, fitted with microtransmitters, and released into the Sacramento River in late April survive the arduous journey to San Francisco Bay and the ocean beyond.
The study of the survival to adulthood of these 900 young fish is part of an ambitious three-year $1.4 million pilot project aimed at learning if the rice fields can play an important role in providing habitat for salmon, as they already do for sandhill cranes and other waterfowl.
“The growers are very much into it,” said Paul Buttner, California Rice Commission project manager for the Helping Salmon in the Sacramento Valley project. “They understand the salmon fishery in the Sacramento Valley needs help, and if the rice fields can be part of it they find that exciting.”
Growers and researchers from the UC Davis Center for Watershed Sciences, the California Department of Fish and Wildlife and California Trout came together to study how the fields can provide young salmon with nutritious food and protection from predators until they are ready to begin the long trip down the Sacramento River.
“We’re hoping to find that if salmon have a chance to get bigger, more of them will make it,” Buttner said. “A very few of them normally make it all the way to the ocean.”
In late April, a team of researchers from UC Davis, led by graduate student Rachelle Tallman, carefully inserted microtransmitters into the young fish that make it possible to track them as they make their way to the Golden Gate.
“We will know towards the end of the summer how many of them made it to the San Francisco Bay,” said UC Davis wildlife, fish and conservation biology associate professor Andrew Rypel. “Usually, about 3 to 5% of the fish released from the hatchery make it. Something like 20% would be great; anything above 10% would be good.”
Previous research has already shown the potential for rice fields as breeding grounds for zooplankton, which feed on algae and in turn serve as nutritious food for the young salmon, and as a source of calm water.
“We already know if you put salmon in rice fields they grow incredibly fast,” Buttner said. “The water is calmer than the river, and the fields have an incredibly nutritious food web. What we don’t know is if that means more of them will make it out to the ocean.”
Rice fields that can directly connect to the Sacramento River offer the best opportunity to replicate the habitat that young salmon historically counted on to get off to a healthy start in life.
“We would like them to voluntarily swim out of the field to the river,” Buttner said. “It pretty much has to be inside the levee, and that restricts us to about 30,000 acres of fields in the Sutter Bypass and Yolo Bypass. Historically, the salmon started in the floodplain, not the river. We have places we can replicate the floodplain; we’re test driving the idea of replicating the floodplain.”
Retrieved June 21, 2019 from https://www.dailydemocrat.com/2019/06/20/rice-fields-provide-protected-habitat-for-young-salmon/