{"id":3212,"date":"2020-05-06T08:01:59","date_gmt":"2020-05-06T15:01:59","guid":{"rendered":"http:\/\/calsport.org\/fisheriesblog\/?p=3212"},"modified":"2020-05-05T21:04:09","modified_gmt":"2020-05-06T04:04:09","slug":"spring-2020-sacramento-river-conditions-and-hatchery-releases","status":"publish","type":"post","link":"https:\/\/calsport.org\/fisheriesblog\/?p=3212","title":{"rendered":"Spring 2020 Sacramento River Conditions and Hatchery Releases"},"content":{"rendered":"

Federal and state hatcheries are feeding striped bass with juvenile salmon in the Sacramento River and Delta yet again<\/a> this spring.\u00a0 As of April 22, 2020, hatcheries have released over 16 million salmon smolts into the Sacramento River system (Table 1).\u00a0 While about two-thirds of these releases so far took place under relatively good conditions (moderate flows, flow pulses, and cool water through early April), the latest one-third have been released under increasingly lower flows and high, stressful water temperatures (Figures 1 and 2) that lead to high rates of predation.\u00a0 Hatchery smolts lingering from the earlier releases are also subjected to these conditions.\u00a0 Millions of wild smolts are also at risk, as they too have been emigrating with the early April flow pulse (Figure 3).<\/p>\n

In addition to predatory fish like striped bass, another predaor also lurks in the south Delta: the federal and state export pumps (Figures 4 and 5).<\/p>\n

With millions more hatchery smolts and wild emigrants to come through early June, the prognosis for future adult returns from these fish looks grim unless some effort is exerted by water agencies to increase river flows and Delta inflow\/outflow in the coming weeks.\u00a0 Future hatchery releases this spring should be transported to the Bay.\u00a0 Flow pulses are needed, but those prescribed in the new federal biological opinion are only required in wetter years.\u00a0 Flows in the Sacramento River at a minimum should be above 5000 cfs at Wilkins Slough and above 10,000 cfs at Freeport.\u00a0 Water temperatures should be maintained below 18\u00b0C\/65\u00b0F to give emigrating salmon a chance to survive.<\/p>\n

Table 1.\u00a0 Major Sacramento River hatchery smolt releases in spring 2020.<\/strong>
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Figure 1. Flow and water temperature in the lower Sacramento River at Wilkins Slough spring 2020. Yellow lines denote major hatchery smolt releases into the upper river.<\/p><\/div>\n

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Figure 2. Flow and water temperature in the lower Sacramento River at Freeport in the north Delta spring 2020. Yellow lines denote major hatchery smolt releases into the upper Sacramento River. Magenta lines denote major hatchery smolt releases into the Feather River.<\/p><\/div>\n

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Figure 3. Salmon smolt survey collections of unmarked juvenile hatchery and wild salmon in 2020. Magenta circle outline winter fry movement. Green circles denote spring smolt movement. Note movement peaks coincident with flow pulses.<\/p><\/div>\n

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Figure 4. Salvage of unmarked juvenile hatchery and wild salmon at south Delta export facilities in water year 2019-2020.<\/p><\/div>\n

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Figure 5. Salvage of unmarked juvenile hatchery and wild salmon at south Delta export facilities in water year 2019-2020.<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"

Federal and state hatcheries are feeding striped bass with juvenile salmon in the Sacramento River and Delta yet again this spring.\u00a0 As of April 22, 2020, hatcheries have released over 16 million salmon smolts into the Sacramento River system (Table … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[15,13,5],"tags":[],"class_list":["post-3212","post","type-post","status-publish","format-standard","hentry","category-bay-delta","category-chinook","category-hatcheries"],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/3212","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3212"}],"version-history":[{"count":1,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/3212\/revisions"}],"predecessor-version":[{"id":3222,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/3212\/revisions\/3222"}],"wp:attachment":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3212"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3212"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3212"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}