State of the California Current 2017-18: Still not quite normal in the north and getting interesting in the south

TitleState of the California Current 2017-18: Still not quite normal in the north and getting interesting in the south
Publication TypeJournal Article
Year of Publication2018
AuthorsThompson A.R, Schroeder I.D, Bograd SJ, Hazen E.L, Jacox M.G, Leising A., Wells B.K, Largier J.L, Fisher JL, Jacobson K., Zeman S., Bjorkstedt E.P, Robertson R.R, Chavez F.P, Kahru M, Goericke R, McClatchie S., Peabody C.E, Baumgartner T.R, Lavaniegos B.E, Gomez-Valdes J., Brodeur R.D, Daly E.A, Morgan C.A, Auth T.D, Burke B.J, Field J., Sakuma K., Weber E.D, Watson W, Coates J., Schoenbaum R., Rogers-Bennett L., Suryan R.M, Dolliver J., Loredo S., Zamon J.E, Schneider S.R, Golightly R.T, Warzybok P., Jahncke J., Santora J.A, Thompson S.A, Sydeman W., Melin S.R
Volume59
Pagination2-66
Date Published2018/12
Type of ArticleArticle
ISBN Number0575-3317
Accession NumberWOS:000496152500001
Keywordsabundance; climate; current system; Fisheries; oceanographic conditions; pacific; Pelagic ecosystem; predator diets; sea lions; variability; zalophus-californianus
Abstract

Following the marine heat wave of 2014-16, the California Current System (CCS) trended towards more typical conditions north of Point Conception, California, from mid-2017 to mid-2018, but became highly abnormal in the south by mid-2018.Two basinscale indices (Pacific Decadal Oscillation and Oceanic Nino Index) were close to neutral, but the North Pacific Gyre Oscillation was extremely low at the end of 2017 and beginning of 2018. Regional analyses demonstrated that upwelling was close to normal throughout most of the CCS with the exception of high upwelling from northern California to Washington in summer and fall of 2017. Sea surface temperature was close to normal throughout most of the CCS but warmed to record levels in summer 2018 in southern California and northern Baja California. In spring 2018, surface chlorophyll a was negatively anomalous throughout most of the US West Coast with localized hot spots around the Columbia River, in the Gulf of Farallones, and Monterey Bay. Lipid-rich copepod densities and sizes returned to normal levels in the northern CCS, and euphausiid abundances were above average in central California but below average in southern California in spring 2018. Abundances of 7 zooplankton taxa were slightly to well above average off of northern Baja California in late 2017. Pyrosomes, which are associated with warm water, were found throughout the CCS. The fish assemblage off Oregon and Washington was comprised of both northern and southern/offshore species. In the central region (near Monterey Bay) most fishes were close to long-term mean abundances; however, adult northern anchovy (Engraulis mordax) abundance was the highest on record. The ichthyoplankton assemblage off southern California had a tropical signal similar to 2014-15 as warm-water associated mesopelagic abundances were close to record highs and cold water mesopelagics abundances were very low.Anchovy larvae abundances in southern California were the highest since the 1960s. Indicators that can affect salmon survival were mixed in 2018. On the one hand, several indices forecast high salmon return (moderate-high salmon yearling abundance, high larval fish (salmon prey) abundance, normal lipid-rich copepod abundances). On the other hand, low survival was predicted by high fall PDO, high abundances of offshore larval fishes, and above average abundance of lipid-poor copepods.This unusual mix of indicators makes it difficult to forecast salmon returns in upcoming years. Common murre (Urfa aalge) reproduction was historically low in the northern CCS in 2017 as colonies experienced complete reproductive failure both at Yaquina Head, Oregon, and Castle Rock, California. In both cases, forage was scarce, birds conducted long foraging excursions which left eggs unattended for extended periods, and many eggs were consumed by avian predators. Brandt's (Phalacrocorax peniscillatus) and pelagic (P. pelagicus) cormorants had above average reproductive success in 2017 at Yaquina Head, but Brandt's cormorant also had total reproductive failure in 2017 at Castle Rock. At Southeast Farallon Island murre, Brandt's cormorant, and pelagic cormorant productivity was close to average in 2017, and Brandt's cormorant and murre were slightly above average in 2018. Preliminary 2018 results fromYaquina Head also indicated that murre successfully produced chicks for the first time since 2014. At-sea bird surveys in the north demonstrated that sooty shearwater and common murre abundances were historically low in 2017, but increased to some of the highest values on record in 2018. By contrast, the at-sea surveys off central California found that murre densities were anomalously high in 2017 but fell to an average level in 2018. Improving California sea lion (Zalophus californianus) pup condition continued from 2016 into 2017 as live pup counts, pup weight, and rate of growth were above average. Augmented pup conditions in 2016-17 was likely driven by increased availability of anchovy, as anchovy remains were found in nearly 100% of sea lion scat. There were record high encounters with Humpback whales (Megaptera novaeangliae) off central California in 2018. Overall, much of the CCS was in more of a normal state through mid-2018 relative to the past 5 years. However, remnants of the 2014-16 marine heat wave were still resonating in the north, and another highly anomalously warm water event affected the southern part of the CCS in summer 2018. Thus, while the CCS was returning to typical conditions in the north, it was anything but normal in the south in 2018.

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