{"id":3684,"date":"2021-05-25T06:55:30","date_gmt":"2021-05-25T13:55:30","guid":{"rendered":"https:\/\/calsport.org\/fisheriesblog\/?p=3684"},"modified":"2021-05-25T06:55:30","modified_gmt":"2021-05-25T13:55:30","slug":"the-forgotten-green-sturgeon","status":"publish","type":"post","link":"https:\/\/calsport.org\/fisheriesblog\/?p=3684","title":{"rendered":"The Forgotten Green Sturgeon"},"content":{"rendered":"

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Adult Green Sturgeon<\/strong>\u00a0and General Life History –\u00a0 <\/strong>Source<\/a><\/p>\n

The Southern Green Sturgeon<\/a> is an anadromous fish species that spawns in the upper Sacramento River near Red Bluff CA.\u00a0 It is a state and federal listed endangered species.\u00a0 Adults migrate from the ocean to spawn in April-May in gravel\/cobble riffles and pools.1<\/a><\/sup>\u00a0 The eggs hatch in approximately 12 days.\u00a0 The young larval or fry are susceptible to stress and mortality if water temperature warm too quickly into the 65-70o<\/sup>F range.\u00a0 Optimal water temperatures for embryos and larvae are 60-65o<\/sup>F.2<\/a><\/sup>\u00a0 Survival declines at higher temperatures, with 68o<\/sup>F considered lethal.<\/p>\n

The fry grow quickly and begin moving downstream from mid-May to mid-July, as shown by screw trap collections at the Red Bluff Diversion Dam (Figures 1 and 2).\u00a0 It is the reaches below Red Bluff downstream into the middle river near Wilkins Slough where larvae-fry are vulnerable to excessive spring-season water temperatures.\u00a0 There are minimal available records of juvenile survival in the middle and lower river, although some data indicate they do not move to the Delta and Bay until the first fall rains.<\/p>\n

Juvenile production measured at Red Bluff is lower in drought years (Figure 2) as a consequence of low flows and high water temperatures. With water temperatures already high in early May 2021 (Figure 3), the prognosis for young green sturgeon production is not good.<\/p>\n

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Figure 1. Screw traps at Red Bluff Diversion Dam in Sacramento River. USFWS photo.<\/p><\/div>\n

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Figure 2. Green sturgeon collections in Red Bluff screw traps 2003-2012. Note poor survival in drought years 2007 through 2009. Source<\/a>.<\/p><\/div>\n

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Figure 3. Water temperature of the Sacramento River at Red Bluff (RDB rm 240) and Wilkins Slough (WLK rm 125) April-June in 2014, 2015, and 2021. Note the lethal water temperature for green sturgeon larvae is considered to be 68o<\/sup>F.<\/p><\/div>\n

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  1. Brown, K. Evidence of spawning by green sturgeon,\u00a0Acipenser medirostris<\/em>, in the upper Sacramento River, California.\u00a0Environ Biol Fish<\/em>\u00a079,\u00a0<\/strong>297\u2013303 (2007). https:\/\/doi.org\/10.1007\/s10641-006-9085-5<\/a> ↩<\/a><\/span><\/li>\n
  2. https:\/\/www.waterboards.ca.gov\/waterrights\/water_issues\/programs\/bay_delta\/california_waterfix\/exhibits\/docs\/petitioners_exhibit\/dwr\/part2\/DWR-1102%20Van%20Eenennaam%20et%20al.%202005.pdf <\/a> ↩<\/a><\/span><\/li>\n<\/ol>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

    Adult Green Sturgeon\u00a0and General Life History –\u00a0 Source The Southern Green Sturgeon is an anadromous fish species that spawns in the upper Sacramento River near Red Bluff CA.\u00a0 It is a state and federal listed endangered species.\u00a0 Adults migrate from … 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":[20,12],"tags":[],"class_list":["post-3684","post","type-post","status-publish","format-standard","hentry","category-sturgeon","category-water-quality"],"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\/3684","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=3684"}],"version-history":[{"count":3,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/3684\/revisions"}],"predecessor-version":[{"id":3692,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=\/wp\/v2\/posts\/3684\/revisions\/3692"}],"wp:attachment":[{"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3684"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3684"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/calsport.org\/fisheriesblog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3684"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}