Cargando…

Reconciling fish and farms: Methods for managing California rice fields as salmon habitat

Rearing habitat for juvenile Chinook Salmon (Oncorhynchus tshawytscha) in California, the southernmost portion of their range, has drastically declined throughout the past century. Recently, through cooperative agreements with diverse stakeholders, winter-flooded agricultural rice fields in Californ...

Descripción completa

Detalles Bibliográficos
Autores principales: Holmes, Eric J., Saffarinia, Parsa, Rypel, Andrew L., Bell-Tilcock, Miranda N., Katz, Jacob V., Jeffres, Carson A.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904208/
https://www.ncbi.nlm.nih.gov/pubmed/33626050
http://dx.doi.org/10.1371/journal.pone.0237686
_version_ 1783654884151656448
author Holmes, Eric J.
Saffarinia, Parsa
Rypel, Andrew L.
Bell-Tilcock, Miranda N.
Katz, Jacob V.
Jeffres, Carson A.
author_facet Holmes, Eric J.
Saffarinia, Parsa
Rypel, Andrew L.
Bell-Tilcock, Miranda N.
Katz, Jacob V.
Jeffres, Carson A.
author_sort Holmes, Eric J.
collection PubMed
description Rearing habitat for juvenile Chinook Salmon (Oncorhynchus tshawytscha) in California, the southernmost portion of their range, has drastically declined throughout the past century. Recently, through cooperative agreements with diverse stakeholders, winter-flooded agricultural rice fields in California’s Central Valley have emerged as ecologically functioning floodplain rearing habitat for juvenile Chinook Salmon. From 2013 to 2016, we conducted a series of experiments examining methods to enhance habitat benefits for fall-run Chinook Salmon reared on winter-flooded rice fields in the Yolo Bypass, a modified floodplain managed for flood control, agriculture, and wildlife habitat in the Sacramento River Valley of California. Investigations included studying the effect of 1) post-harvest field substrate; 2) depth refugia; 3) duration of field drainage; and 4) duration of rearing occupancy on in-situ diet, growth and survival of juvenile salmon. Post-harvest substrate treatment had only a small effect on the lower trophic food web and an insignificant effect on growth rates or survival of rearing hatchery-origin, fall-run Chinook Salmon. Similarly, depth refugia, created by trenches dug to various depths, also had an insignificant effect on survival. Rapid field drainage yielded significantly higher survival compared to drainage methods drawn out over longer periods. A mortality of approximately one third was observed in the first week after fish were released in the floodplain. This initial mortality event was followed by high, stable survival rates for the remainder of the 6-week duration of floodplain rearing study. Across years, in-field survival ranged 7.4–61.6% and increased over the course of the experiments. Despite coinciding with the most extreme drought in California’s recorded history, which elevated water temperatures and reduced the regional extent of adjacent flooded habitats which concentrated avian predators, the adaptive research framework enabled incremental improvements in design to increase survival. Zooplankton (fish food) in the winter-flooded rice fields were 53-150x more abundant than those sampled concurrently in the adjacent Sacramento River channel. Correspondingly, observed somatic growth rates of juvenile hatchery-sourced fall-run Chinook Salmon stocked in rice fields were two to five times greater than concurrently and previously observed growth rates in the adjacent Sacramento River. The abundance of food resources and exceptionally high growth rates observed during these experiments illustrate the potential benefits of using existing agricultural infrastructure to approximate the floodplain wetland physical conditions and hydrologic patterns (shallow, long-duration inundation of cool floodplain habitats in mid-winter) under which Chinook Salmon evolved and to which they are adapted.
format Online
Article
Text
id pubmed-7904208
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-79042082021-03-03 Reconciling fish and farms: Methods for managing California rice fields as salmon habitat Holmes, Eric J. Saffarinia, Parsa Rypel, Andrew L. Bell-Tilcock, Miranda N. Katz, Jacob V. Jeffres, Carson A. PLoS One Research Article Rearing habitat for juvenile Chinook Salmon (Oncorhynchus tshawytscha) in California, the southernmost portion of their range, has drastically declined throughout the past century. Recently, through cooperative agreements with diverse stakeholders, winter-flooded agricultural rice fields in California’s Central Valley have emerged as ecologically functioning floodplain rearing habitat for juvenile Chinook Salmon. From 2013 to 2016, we conducted a series of experiments examining methods to enhance habitat benefits for fall-run Chinook Salmon reared on winter-flooded rice fields in the Yolo Bypass, a modified floodplain managed for flood control, agriculture, and wildlife habitat in the Sacramento River Valley of California. Investigations included studying the effect of 1) post-harvest field substrate; 2) depth refugia; 3) duration of field drainage; and 4) duration of rearing occupancy on in-situ diet, growth and survival of juvenile salmon. Post-harvest substrate treatment had only a small effect on the lower trophic food web and an insignificant effect on growth rates or survival of rearing hatchery-origin, fall-run Chinook Salmon. Similarly, depth refugia, created by trenches dug to various depths, also had an insignificant effect on survival. Rapid field drainage yielded significantly higher survival compared to drainage methods drawn out over longer periods. A mortality of approximately one third was observed in the first week after fish were released in the floodplain. This initial mortality event was followed by high, stable survival rates for the remainder of the 6-week duration of floodplain rearing study. Across years, in-field survival ranged 7.4–61.6% and increased over the course of the experiments. Despite coinciding with the most extreme drought in California’s recorded history, which elevated water temperatures and reduced the regional extent of adjacent flooded habitats which concentrated avian predators, the adaptive research framework enabled incremental improvements in design to increase survival. Zooplankton (fish food) in the winter-flooded rice fields were 53-150x more abundant than those sampled concurrently in the adjacent Sacramento River channel. Correspondingly, observed somatic growth rates of juvenile hatchery-sourced fall-run Chinook Salmon stocked in rice fields were two to five times greater than concurrently and previously observed growth rates in the adjacent Sacramento River. The abundance of food resources and exceptionally high growth rates observed during these experiments illustrate the potential benefits of using existing agricultural infrastructure to approximate the floodplain wetland physical conditions and hydrologic patterns (shallow, long-duration inundation of cool floodplain habitats in mid-winter) under which Chinook Salmon evolved and to which they are adapted. Public Library of Science 2021-02-24 /pmc/articles/PMC7904208/ /pubmed/33626050 http://dx.doi.org/10.1371/journal.pone.0237686 Text en © 2021 Holmes et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Holmes, Eric J.
Saffarinia, Parsa
Rypel, Andrew L.
Bell-Tilcock, Miranda N.
Katz, Jacob V.
Jeffres, Carson A.
Reconciling fish and farms: Methods for managing California rice fields as salmon habitat
title Reconciling fish and farms: Methods for managing California rice fields as salmon habitat
title_full Reconciling fish and farms: Methods for managing California rice fields as salmon habitat
title_fullStr Reconciling fish and farms: Methods for managing California rice fields as salmon habitat
title_full_unstemmed Reconciling fish and farms: Methods for managing California rice fields as salmon habitat
title_short Reconciling fish and farms: Methods for managing California rice fields as salmon habitat
title_sort reconciling fish and farms: methods for managing california rice fields as salmon habitat
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7904208/
https://www.ncbi.nlm.nih.gov/pubmed/33626050
http://dx.doi.org/10.1371/journal.pone.0237686
work_keys_str_mv AT holmesericj reconcilingfishandfarmsmethodsformanagingcaliforniaricefieldsassalmonhabitat
AT saffariniaparsa reconcilingfishandfarmsmethodsformanagingcaliforniaricefieldsassalmonhabitat
AT rypelandrewl reconcilingfishandfarmsmethodsformanagingcaliforniaricefieldsassalmonhabitat
AT belltilcockmirandan reconcilingfishandfarmsmethodsformanagingcaliforniaricefieldsassalmonhabitat
AT katzjacobv reconcilingfishandfarmsmethodsformanagingcaliforniaricefieldsassalmonhabitat
AT jeffrescarsona reconcilingfishandfarmsmethodsformanagingcaliforniaricefieldsassalmonhabitat