2022 marked the third consecutive La Niña and extended the longest consecutive stretch of negative Oceanic Niño Index since 1998-2001. While physical and biological conditions in winter and spring largely adhered to prior La Niña conditions, summer and fall were very different. Similar to past La Niña events, in winter and spring coastal upwelling was either average or above average, temperature average or below average, salinity generally above average. In summer and fall, however, upwelling and temperature were generally average or slightly below average, salinity was close to average and chlorophyll a was close to average. Again, as during prior La Niña events, biomass of northern/southern copepods was above/below average off Oregon in winter, and body size of North Pacific krill in northern California was above average in winter. By contrast, later in the year the abundance of northern krill dropped off Oregon while southern copepods increased and body sizes of North Pacific krill fell in northern California. Off Oregon and Washington abundances of market squid and Pacific pompano (indicators of warm, non-typical La Niña conditions) were high. In the 20th century, Northern anchovy recruitment tended to be high during cold conditions, but despite mostly warm conditions from 2015-2021 anchovy populations boomed and remained high in 2022. Resident seabird reproductive success, which tended in the past to increase during productive La Niña conditions was highly variable throughout the system as common murre and pelagic cormorant, experienced complete reproductive failure at Yaquina Head, Oregon while Brandt’s cormorant reproduction was average. At three sampling locations off central California, however, common murre reproduction was close to or above average while both pelagic and Brandt’s cormorant were above average. California sealion reproduction has been above average each year since 2016, and pup weight was also above average in 2022, likely in response not to La Niña or El Niño but continuous high abundance of anchovy. The highly variable and often unpredictable physical and biological conditions in 2022 highlight a growing recognition of disconnects between basin-scale indices and local conditions in the CCE. “July-December 2022 is the biggest outlier from individual “strong” La Niña (events) ever going back to the 50s.” – Nate Mantua

In late 2020, models predicted that a strong La Niña would take place for the first time since 2013, and we assessed whether physical and biological indicators in 2021 were similar to past La Niñas in the California Current Ecosystem (CCE). The Pacific Decadal Oscillation and Oceanic Niño Index indeed remained negative throughout 2021; the North Pacific Gyre Oscillation Index, however, remained strongly negative. The seventh largest marine heatwave on record was unexpectedly present from April to the end of 2021; however, similar to past La Niñas, this mass of warm water mostly remained seaward of the continental shelf. As expected from past La Niñas, upwelling and chlorophyll were mostly high and sea surface temperature was low throughout the CCE; however, values were close to average south of Point Conception. Similar to past La Niñas, abundances of lipid-rich, northern copepods off Oregon increased. In northern California, unlike past La Niñas, the body size of North Pacific krill (Euphausia pacifica) was close to average. Predictably, overall krill abundance was above average in far northern California but, unexpectedly, below average south of Cape Mendocino. Off Oregon, similar to past La Niñas, larval abundances of three of six coastal species rose, while five of six southern/offshore taxa decreased in 2021. Off California, as expected based on 2020, Northern Anchovy (Engraulis mordax) were very abundant, while Pacific Sardine (Sardinops sagax) were low. Similar to past La Niñas, market squid (Doryteuthis opalescens) and young of the year (YOY) Pacific Hake (Merluccius pacificus), YOY sanddabs (Citharichthys spp.), and YOY rockfishes (Sebastes spp.) increased. Southern mesopelagic (e.g., Panama lightfish Vinciguerria lucetia, Mexican lampfish Triphoturus mexicanus) larvae decreased as expected but were still well above average, while northern mesopelagic (e.g., northern lampfish Stenobrachius leucopsarus) larvae increased but were still below average. In line with predictions, most monitored bird species had above-average reproduction in Oregon and California. California sea lion (Zalophus californianus) pup count, growth, and weight were high given the abundant Anchovy forage. The CCE entered an enduring La Niña in 2021, and assessing the responses of various ecosystem components helped articulate aspects of the system that are well understood and those that need further study.

Citation: Weber ED, Auth TD, Baumann-Pickering S, Baumgartner TR, Bjorkstedt EP, Bograd SJ, Burke BJ, Cadena-Ramírez JL, Daly EA, de la Cruz M, Dewar H, Field JC, Fisher JL, Giddings A, Goericke R, Gomez-Ocampo E, Gomez-Valdes J, Hazen EL, Hildebrand J, Horton CA, Jacobson KC, Jacox MG, Jahncke J, Kahru M, Kudela RM, Lavaniegos BE, Leising A, Melin SR, Miranda-Bojorquez LE, Morgan CA, Nickels CF, Orben RA, Porquez JM, Portner EJ, Robertson RR, Rudnick DL, Sakuma KM, Santora JA, Schroeder ID, Snodgrass OE, Sydeman WJ, Thompson AR, Thompson SA, Trickey JS, Villegas-Mendoza J, Warzybok P, Watson W and Zeman SM (2022) Corrigendum: State of the California Current 2019–2020: Back to the Future With Marine Heatwaves? Front. Mar. Sci. 9:863176. doi: 10.3389/fmars.2022.863176 Corrigendum: State of the California Current 2019–2020: Back to the Future With Marine Heatwaves?

The California Current System (CCS) has experienced large fluctuations in environmental conditions in recent years that have dramatically affected the biological community. Here we synthesize remotely sensed, hydrographic, and biological survey data from throughout the CCS in 2019–2020 to evaluate how recent changes in environmental conditions have affected community dynamics at multiple trophic levels. A marine heatwave formed in the north Pacific in 2019 and reached the second greatest area ever recorded by the end of summer 2020. However, high atmospheric pressure in early 2020 drove relatively strong Ekman-driven coastal upwelling in the northern portion of the CCS and warm temperature anomalies remained far offshore. Upwelling and cooler temperatures in the northern CCS created relatively productive conditions in which the biomass of lipid-rich copepod species increased, adult krill size increased, and several seabird species experienced positive reproductive success. Despite these conditions, the composition of the fish community in the northern CCS remained a mixture of both warm- and cool-water-associated species. In the southern CCS, ocean temperatures remained above average for the seventh consecutive year. Abundances of juvenile fish species associated with productive conditions were relatively low, and the ichthyoplankton community was dominated by a mixture of oceanic warm-water and cosmopolitan species. Seabird species associated with warm water also occurred at greater densities than cool-water species in the southern CCS. The population of northern anchovy, which has been resurgent since 2017, continued to provide an important forage base for piscivorous fishes, offshore colonies of seabirds, and marine mammals throughout the CCS. Coastal upwelling in the north, and a longer-term trend in warming in the south, appeared to be controlling the community to a much greater extent than the marine heatwave itself.

Norway has the highest participation rate in marine recreational fisheries (MRF) in Europe, and is popular among marine tourist anglers. Fishing licences are not required for marine recreational anglers, and the complex and long coastline makes on-site surveys a challenge. A novel approach for spatial sampling was developed and tested in on-site surveys, as part of a National study of MRF using multiple sampling frames including a telephone screening survey based on the national telephone directory. Field surveys were conducted in Troms and Hordaland Counties, and in the Oslofjord. We created spatial sampling frames of modified Voronoi polygons with continuous sea-surface area, with clusters of polygons as primary sampling units (PSUs). Interviews of intercepted anglers were obtained quarterly from a stratified sample of PSUs searched by boat. Many anglers interviewed in Troms (63%) and Hordaland (53%) were non-residents, of which 92 and 66% stayed in registered tourist fishing camps, respectively. Most anglers in the Oslofjord were residents, and in the inner Oslofjord, 63% of the resident anglers interviewed on-site were born outside Norway, which was not reflected in the telephone survey. Thus, if only off-site methods were used to map Norwegian MRF, this could lead to biased results in some regions.

Multidisciplinary, integrated ocean observing programs provide critical data for monitoring the effects of climate change on marine ecosystems. California Cooperative Oceanic Fisheries Investigations (CalCOFI) samples along the US West Coast and is one of the world’s longest-running and most comprehensive time series, with hydrographic and biological data collected since 1949. The pairing of ecological and physical measurements across this long time series informs our understanding of how the California Current marine ecosystem responds to climate variability. By providing a baseline to monitor change, the CalCOFI time series serves as a Keeling Curve for the California Current. However, challenges remain in connecting the data collected from long-term monitoring programs with the needs of stakeholders concerned with climate change adaptation (i.e., resource managers, policy makers, and the public), including for the fisheries and aquaculture sectors. We use the CalCOFI program as a case study to ask: how can long-term ocean observing programs inform ecosystem based management efforts and create data flows that meet the needs of stakeholders working on climate change adaptation? Addressing this question and identifying solutions requires working across sectors and recognizing stakeholder needs. Lessons learned from CalCOFI can inform other regional monitoring programs around the world, including those done at a smaller scale in developing countries.

The California Current Ecosystem (CCE) has been in a primarily warm state since 2014, and this pattern largely continued into 2019. The CCE experienced a mild El Nino from late 2018 into 2019, and basin-scale indicators reflected this condition (elevated Oceanic Nitio Index and Pacific Decadal Oscillation; table 1). Despite the El Nino, spring upwelling was above average between southern California and Washington but below average in Baja California. Sea surface temperature (SST) was mostly near the long-term average between Washington and southern California, while surface chlorophyll a was above average in Oregon/Washington and slightly below average in most of California in spring/early summer 2019. SST changed dramatically by fall 2019, however, as a marine heat wave (MHW) that formed in May 2019 in the Gulf of Alaska impinged upon the West Coast of the United States. The expansion of the 2019 MHW followed a similar pattern to the 2014-15 MHW. Off Oregon, the zooplankton assemblage was in a mixed state as southern copepods were close to average while northern copepod abundances were positively anomalous in 2019. Off northern California, Euphausia pacifica body size was smaller than average. Euphausid abundances were well below average in both central and southern California in 2019. In the north, winter 2019 larval fish abundances were high and dominated by offshore taxa that are associated with warm conditions; spring larval and post-larval biomass were close to average; and spring surface trawls observed record-high market squid (Doryteuthis opalescens) abundances. The single most important finding in 2019 was that northern anchovy (Engraulis tnordax) adults and larvae were at record-high abundances in central and southern California. In central California, market squid and Pacific sardine (Sardinops sagax) were also abundant. In southern California warm-water mesopelagic fishes have been very abundant since 2014, and this trend continued into 2019. Indicators for future salmon returns were mixed in 2019. The abundance of northern copepods, which correlate positively with returns, was high. However, abundances of yearling Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch), which also correlate positively with returns, were slightly below average. Winter ichthyoplankton was comprised mostly of southern or offshore taxa, which bodes poorly for future salmon returns. Seabird (common murre [Urfa aalge]; Brandt's cormorant [Phalacrocorax penidllatus]; and pelagic cormorant [Phalacrocorax pelagicus]) productivity off Oregon was the highest in years in both 2018 and 2019. In 2018, common murre chicks in Oregon consumed large amounts of young-of-the-year flatfish, a prey item known to be conducive to chick survival. Despite the prevalence of northern anchovy in central California, common murre and Brand's cormorant production was low in Southeast Farallon Island as these birds were unable to feed optimally on northern anchovy, and there was a scarcity of more appropriate prey such as young-of-the-year flat-fishes or rockfishes. California sea lions (Zalophus californianus), by contrast, benefitted greatly from the large northern anchovy forage base. In 2018, live pup count, weight, and growth rate were anomalously high, and northern anchovy remains occurred in >85% of scat samples. Humpback whale (Megaptera novaeangliae) sightings were also very high in 2019, likely because humpback whales congregated near shore to feed on northern anchovy.

Fish habitat models based on remotely-sensed data may be limited by satellite coverage and availability. We compared the fit and predictive power of Random Forest habitat classifiers that were developed using predictors derived from a coupled biophysical model (i.e., modeled predictors) versus similar classifiers that used remotely-sensed satellite data for two data sets (eggs and adults) and four species that occur widely in the California Current system. When tested on independent data, classifiers of spawning habitat that used derived predictors (derived classifiers) had nearly identical accuracies (0–2% difference) to similar classifiers based on satellite data (satellite classifiers). Accuracies of derived classifiers of adult habitat were within −8% to +7% of comparable satellite classifiers. Accuracies of both types of classifiers on test data were much greater for Northern anchovy Engraulis mordax and Pacific hake Merluccius productus (0.75–0.97) than for jack mackerel Trachurus symmetricus and Pacific sardine Sardinops sagax (0.61–0.72), and generally were greater for classifiers of spawning habitat than for adult habitat. Specificity was very good for both types of classifiers, but sensitivity was poor, because classifiers identified potential habitat which was not fully occupied. Adults of all species used a broader range of habitat conditions during summer than during the spring spawning period. Derived classifiers have some advantages over satellite classifiers; they are not limited by cloud cover and they can make predictions in near real-time or the short-term future. However, there was no consistent improvement in the accuracy of derived predictors that included modeled zooplankton concentrations over comparable satellite classifiers that included reflectance/chlorophyll concentration.

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.

To correctly interpret trends in species’ abundance in long time series it is essential to account and correct for biases that may arise in association with changes in sampling methodology. We assess how gear changes for oblique plankton net tows (from 1 m diameter ring to 0.71 m diameter bongo net in 1977) affected ichthyoplankton abundance estimates from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program. Paired ring and bongo net samples were analyzed from 133 stations sampled in 1977–78. To quantitatively correct for net-associated bias, we first modeled abundance in bongo nets as a function of abundance in ring nets for larvae and eggs summed across all taxa during day and night with generalized linear models (GLM; identity link with gamma error structure). Models suggest that greater visual avoidance for ring than bongo nets induces bias in abundance estimates as slope estimates were greater than 1 for combined larvae during the day but did not differ significantly from 1 for combined larvae at night, or eggs during day or night. Ratios of summed abundances between bongo and ring nets for the 15 most common taxa indicated that there were significantly higher abundances for 4 taxa in the bongo than the ring net during the day but values did not differ at night between net types. To make data collected in ring nets before 1978 more comparable to data from bongo nets our results suggest it is necessary to adjust abundance estimates during the day from ring nets by a factor of 2 for Cyclothone spp., 2.17 for Diogenichthys spp., 2.06 for Engraulis mordax, and 1.53 for Vinciguerria spp. It may also be necessary to reevaluate results from past studies that utilize the CalCOFI larval time series that did not correct for net bias. More data are needed to ascertain the effect of net change on species such as Sardinops sagax or Tarletonbeania crenularis that were uncommon in the late 1970s but have been encountered frequently in recent years. INTRODUCTION Long time series are essential for truly understanding the mechanisms governing variability in the dynamics of populations and communities in all ecosystems (Krebs et al. 2001; McClatchie 2014). Short-term fluctuations are often nested within long-period dynamics and attempts to discern the causes of species variability over short time periods may produce erroneous conclusions (McClatchie et al. 2017). This is particularly true in an era of rapid climate change as the effect of changes in environmental conditions on ecosystems can be conceptualized only when placed in the context of a long time series. Therefore, it is extremely important for species management and conservation programs to maintain and build upon long time series over upcoming years and decades. Equally important as maintaining long time series is ensuring that samples collected over time are comparable to one another. Bias can arise if systematic differences in collection methods that affect the probability of capturing an organism are imposed upon the time series (MacKenzie et al. 2002). For example, trends from fisherydependent data may not reflect true population dynamics of a fished species if the fleet introduced more effective gear for catching the targeted species at some point in the time series. Accounting for methodological differences in data collection is imperative to properly interpret potential changes in species abundances for time series analysis (MacKenzie et al. 2005). The California Cooperative Oceanic Fisheries Investigations (CalCOFI) program provides some of the most complete marine ecosystem monitoring data in the world. CalCOFI has continuously sampled biological (plankton tows) and oceanographic conditions (CTD and water collections) from the same 66 core stations off southern California since 1951 (McClatchie 2014). From a biological perspective, the resultant data give information on variability in the distribution and abundance of zooplankton (McGowan and Walker 1985; McGowan et al. 1998; Lavaniegos and Ohman 2007) and ichthyoplankton (Hsieh et al. 2005; Hsieh et al. 2006; Hsieh et al. 2009; Lindegren et al. 2016) over more than six decades. At several points in the time series CalCOFI plankton sampling was changed to introduce methodological improvements. In all years, samples were obtained by lowering a net to a set depth and towing it obliquely (at a 45 ̊ angle) to the surface at a constant speed. However, THOMPSON ET AL.: CORRECTING FOR BIAS IN CALCOFI ICHTHYOPLANKTON ABUNDANCE ESTIMATES CalCOFI Rep., Vol. 58, 2017 114 lected using both nets at the same 160 stations during seven CalCOFI cruises between winter 1977 and summer 1978. At present, net effects on sampling efficiency have been thoroughly vetted for zooplankton (Smith 1974; Brinton and Townsend 1981; Ohman and Smith 1995; Rebstock 2001; Ohman and Lavaniegos 2002). However, with the exception of an investigation on northern anchovy, Engraulis mordax (Hewitt 1980), comparable analyses have not been published for ichthyoplankton. Here we evaluate if larval abundance estimates are biased by gear type and test the hypothesis that bias will be greater during the day when larvae would be able to better see and avoid the ring than the bongo net.

The Pacific sardine, Sardinops sagax, is a highly migratory coastal pelagic species that occurs from the tip of Baja California to the Gulf of Alaska and in the Gulf of California. We used fishery-independent egg surveys to characterize the relative amounts of sardine spawning habitat in the exclusive economic zones (EEZ5) of Mexico and the US during spring 2000-13. Most eggs were captured in the US EEZ from San Francisco to the Mexico-US border in all years sampled. A small fraction ranging from 0% to 10% of all eggs captured occurred in the Mexican EEZ, usually from Punta Eugenia north to the border. The abundance and distribution of eggs found in warmer waters between 15 degrees C to 18 degrees C off northern Baja California appear to be dependent on periods of more intense flow of the California Current, when sardine belonging to the northern subpopulation found in central and southern California extends southward into the nearshore area off Baja California. However, a small fraction of the southern subpopulation may also have spawned in coastal areas of the US-Mexican border during May in some years.

Author(s): Wells, Brian K; Schroeder, Isaac D; Bograd, Steven J; Hazen, Elliott L; Jacox, Michael G; Leising, Andrew; Mantua, Nathan; Santora, Jarrod A; Fisher, Jennifer; Peterson, William T; Bjorkstedt, Eric; Robertson, Roxanne R; Chavez, Francisco P; Goericke, Ralf; Kudela, Raphael; Anderson, Clarissa; Lavaniegos, Bertha E; Gomez-Valdes, Jose; Brodeur, Richard D; Daly, Elizabeth A; Morgan, Cheryl A; Auth, Toby D; Field, John C; Sakuma, Keith; McClatchie, Sam; Thompson, Andrew R; Weber, Edward D; Watson, William; Suryan, Robert M; Parrish, Julia; Dolliver, Jane; Loredo, Stephanie; Porquez, Jessica M; Zamon, Jeannette E; Schneider, Stephanie R; Golightly, Richard T; Warzybok, Pete; Bradley, Russell; Jahncke, Jaime; Sydeman, William; Melin, Sharon R; Hildebrand, John A; Debich, Amanda J; Thayre, Bruce

Author(s): McClatchie, S; Goericke, R; Leising, A; Auth, TD; Bjorkstedt, E; Robertson, RR; Brodeur, RD; Du, X; Daly, EA; Morgan, CA; Chavez, FP; Debich, AJ; Hildebrand, J; Field, J; Sakuma, K; Jacox, MG; Kahru, M; Kudela, R; Anderson, C; Lavaniegos, BE; Gomez-Valdes, J; Jimenez-Rosenberg, SPA; McCabe, R; Melin, SR; Ohman, MD; Sala, LM; Peterson, B; Fisher, J; Schroeder, ID; Bograd, SJ; Hazen, EL; Schneider, SR; Golightly, RT; Suryan, RM; Gladics, AJ; Loredo, S; Porquez, JM; Thompson, AR; Weber, ED; Watson, W; Trainer, V; Warzybok, P; Bradley, R; Jahncke, J | Abstract: Warm conditions in the North Pacific in 2014-15 were a result of the continuation of the North Pacific marine heat wave, a large area of exceptionally high SST anomalies that originated in the Gulf of Alaska in late 2013. The North Pacific heat wave interacted with an El Nino developing in the equatorial Pacific in 2015. Weekly periods of exceptionally high temperature anomalies (g2˚C) occurred until the start of the El Nino (winter of 2015), when SSTs were still high but not as high as those due to the marine heat wave. During the 2015-16 El Nino, the depth of the 26.0 kg m-3 isopycnal (d26.0) was considerably shallower than during the 1982- 83 and 1997-98 events. The area affected by the marine heat wave and the 2015-16 El Nino in the mixed layer was comparable to the 1997-98 El Nino, but lasted longer. Water column stratification in the upper 100 m during 2015-16 was as strong as the most extreme values during the 1997-98 El Nino. This stratification was primarily driven by the warming of the upper 100 m. Despite notable perturbations, the effects of the 2015- 16 El Nino on hydrographic properties in the CalCOFI domain were not as strong as those observed during the 1997-98 El Nino. Warm ocean conditions, stratification, nutrient suppression, and silicic acid stress likely favored initiation of a toxic Pseudo-nitzschia bloom in fall 2014. Very low zooplankton displacement volumes were associated with anomalously warm and saline surface waters off Baja California. In contrast, during the 1997-98 El Nino, zooplankton volume was near average. Off California, pelagic red crab (Pleuroncodes planipes) adults were abundant in the water column and frequently washed up on beaches of southern California from January 2015 into 2016, and central California by September 2015. Glider measurements of integrated transport up to June 2015 did not detect anomalous northward advection. As expected, HF radar indicated northward surface currents along the central California coast in fall and winter 2015-16. Northward advection appeared to be much stronger during the 1997-98 El Nino. Throughout 2015-16, the zooplankton community on the Oregon shelf was dominated by lipid-poor tropical and sub-tropical copepods and gelatinous zooplankton, indicating poor feeding conditions for small fishes that are prey for juvenile salmon. The presence of rarely encountered species increased copepod species richness during 2015-16 to levels higher than the 1998 El Nino. We infer that the unusual copepod vagrants of 2015-16 originated from an offshore and southwesterly source; an important difference from the southerly origin of vagrants during the 1997-98 El Nino. The very warm conditions caused sardine spawning to shift from central California to Oregon. Mesopelagic fish assemblage off southern California exhibited higher abundances of species with southern affinities, and lower abundances of species with northern affinities. Forage fish (Pacific herring, northern anchovy, and Pacific sardine) were much less abundant in 2015-16 compared to previous years. In contrast, catches of salmon were close to average off northern California. Catches of young-ofthe- year rockfishes were high off central California, but low off both northern and southern California. Seabirds at Southeast Farallon Island in 2015 exhibited reduced breeding populations, reduced breeding success, lower chick growth rates, and lower fledging weights. Common murres were negatively affected in central and northern California, but seabird responses were species-specific. It is clear from the results presented here that the warm anomaly effects on the ecosystem were complicated, regionally specific, and that we do not fully understand them yet.

Warm conditions in the North Pacific in 2014-15 were a result of the continuation of the North Pacific marine heat wave, a large area of exceptionally high SST anomalies that originated in the Gulf of Alaska in late 2013. The North Pacific heat wave interacted with an El Nino developing in the equatorial Pacific in 2015. Weekly periods of exceptionally high temperature anomalies (>2 degrees C) occurred until the start of the El Nino (winter of 2015), when SSTs were still high but not as high as those due to the marine heat wave. During the 2015-16 El Nino, the depth of the 26.0 kg m(-3) isopycnal (d(26.0)) was considerably shallower than during the -1982-83 and 1997-98 events. The area affected by the marine heat wave and the 2015-16 El Nino in the mixed layer was comparable to the 1997-98 El Nino, but lasted longer. Water column stratification in the upper 100 m during 2015-16 was as strong as the most extreme values during the 1997-98 El Nino. This stratification was primarily driven by the warming of the upper 100 m. Despite notable perturbations, the effects of the -2015-16 El Nino on hydrographic properties in the CalCOFI domain were not as strong as those observed during the 1997-98 El Nino. Warm ocean conditions, stratification, nutrient suppression, and silicic acid stress likely favored initiation of a toxic Pseudo-nitzschia bloom in fall 2014. Very low zooplankton displacement volumes were associated with anomalously warm and saline surface waters off Baja California. In contrast, during the 1997-98 El Nino, zooplankton volume was near average. Off California, pelagic red crab (Pleuroncodes planipes) adults were abundant in the water column and frequently washed up on beaches of southern California from January 2015 into 2016, and central California by September 2015. Glider measurements of integrated transport up to June 2015 did not detect anomalous northward advection. As expected, HF radar indicated northward surface currents along the central California coast in fall and winter 2015-16. Northward advection appeared to be much stronger during the 1997-98 El Nino. Throughout 2015-16, the zooplankton community on the Oregon shelf was dominated by lipid-poor tropical and sub-tropical copepods and gelatinous zooplankton, indicating poor feeding conditions for small fishes that are prey for juvenile salmon. The presence of rarely encountered species increased copepod species richness during 2015-16 to levels higher than the 1998 El Nino. We infer that the unusual copepod vagrants of 2015-16 originated from an offshore and southwesterly source; an important difference from the southerly origin of vagrants during the 1997-98 El Nino. The very warm conditions caused sardine spawning to shift from central California to Oregon. Mesopelagic fish assemblage off southern California exhibited higher abundances of species with southern affinities, and lower abundances of species with northern affinities. Forage fish (Pacific herring, northern anchovy, and Pacific sardine) were much less abundant in 2015-16 compared to previous years. In contrast, catches of salmon were close to average off northern California. Catches of young-of-the- year rockfishes were high off central California, but low off both northern and southern California. Seabirds at Southeast Farallon Island in 2015 exhibited reduced breeding populations, reduced breeding success, lower chick growth rates, and lower fledging weights. Common murres were negatively affected in central and northern California, but seabird responses were species-specific. It is clear from the results presented here that the warm anomaly effects on the ecosystem were complicated, regionally specific, and that we do not fully understand them yet.

In 2014, the California Current (similar to 28 degrees-48 degrees N) saw average, or below average, coastal upwelling and relatively low productivity in most locations, except from 38 degrees-43 degrees N during June and July. Chlorophyll-a levels were low throughout spring and summer at most locations, except in a small region around 39 degrees N. Catches of juvenile rockfish (an indicator of upwelling-related fish species) remained high throughout the area surveyed (32 degrees-43 degrees N). In the fall of 2014, as upwelling ceased, many locations saw an unprecedented increase in sea surface temperatures (anomalies as large as 4 degrees C), particularly at 45 degrees N due to the coastal intrusion of an extremely anomalous pool of warm water. This warm surface anomaly had been building offshore in the Gulf of Alaska since the fall of 2013, and has been referred to as the "blob." Values of the Pacific Decadal Oscillation index (PDO) continued to climb during 2014, indicative of the increase in warm coastal surface waters, whereas the North Pacific Gyre Oscillation index (NPGO) saw a slight rebound to more neutral values (indicative of average productivity levels) during 2014. During spring 2015, the upwelling index was slightly higher than average for locations in the central and northern region, but remained below average at latitudes south of 35 degrees N. Chlorophyll a levels were slightly higher than average in similar to 0.5 degrees latitude patches north of 35 degrees N, whereas productivity and phytoplankton biomass were low south of Pt. Conception. Catches of rockfish remained high along most of the coast, however, market squid remained high only within the central coast (36 degrees-38 degrees N), and euphausiid abundance decreased everywhere, as compared to the previous year. Sardine and anchovy were nearly absent from the southern portion of the California Current system (CCS), whereas their larvae were found off the coast of Oregon and Washington during winter for the first time in many years. Waters warmed dramatically in the southern California region due to a change in wind patterns similar to that giving rise to the blob in the broader northeast Pacific. For most of the coast, there were intrusions of species never found before or found at much higher abundances than usual, including fish, crustaceans, tunicates and other gelatinous zooplankton, along with other species often indicative of an El Nino. Thus species richness was high in many areas given the close juxtaposition of coastal upwelling-related species with the offshore warm-water intrusive or El Nino-typical taxa. Thus the California Current by 2015 appears to have transitioned to a very different state than previous observations.

We simulated transport of Pacific sardine eggs captured offshore of California in spring of 2001–2012 using a regional ocean circulation model. Eggs were assumed to have developed into larvae within a few days and were modeled using five behavioral patterns: passive transport, diel vertical migration, diel vertical migration combined with swimming against the current, diel migration combined with migration toward shore, and diel migration combined with migration toward the best habitat. Simulated larvae with no swimming behavior were advected far offshore to poor habitat where they were unlikely to survive. Diel vertical migration resulted in less offshore transport because larvae were less affected by surface currents during the day. However, in half the years simulated nearly all juveniles were also located in poor habitat by late summer in this scenario. Swimming against the current combined with diel vertical migration resulted in similar transport patterns to the diel-vertical-migration scenario because currents dominated the transport of eggs and small larvae during the spring and early summer. Migration toward shore resulted in a large fraction of juveniles being located in appropriate habitat during late summer in all years. Migration toward the best habitat was the best strategy modeled. This strategy resulted in a slightly greater proportion of larvae being located in appropriate habitat at the end of summer than the swimming-toward-shore scenario, despite the fact that most larvae were located farther offshore. These results suggest that larval sardine might use directed horizontal swimming behavior to remain in suitable habitat conditions. A large fraction of larvae were transported south into Mexican waters by late summer in all five scenarios. Surveying juvenile sardines in fall near the border of the U.S. and Mexico may be an efficient means of estimating recruitment because the advection pattern of eggs and larvae to the south is opposite the adult migration pattern to the north. This pattern may cause juveniles to be spatially segregated from adults at the time they are being recruited.

We quantified the effect of mesoscale eddies and streamers on the spatial distribution of Pacific sardine spawning habitat using a merged altimetry data set and a statistical spawning habitat model. The distribution of eggs could be predicted using sea-surface temperature, chlorophyll concentration, and eddy kinetic energy (EKE) similarly to previous studies. Eddies alone did not have a significant additional or emergent effect on the probability of capturing eggs beyond these predictors. Rather, mesoscale features (eddies and streamers) entrained water with the appropriate conditions in terms of temperature, chlorophyll, and EKE. These dynamic features moved appropriate spawning habitat for sardine offshore to areas where appropriate habitat otherwise would not exist. Using centroids of predicted sardine habitat, we showed that sardine recruitment success was inversely correlated with distance from shore of predicted sardine habitat centroids. This indicates that offshore transport has a negative effect on sardine recruitment, despite expanding favorable spawning habitat further offshore.

In 2013, the California current was dominated by strong coastal upwelling and high productivity. Indices of total cumulative upwelling for particular coastal locations reached some of the highest values on record. Chlorophyll a levels were high throughout spring and summer. Catches of upwelling-related fish species were also high. After a moderate drop in upwelling during fall 2013, the California current system underwent a major change in phase. Three major basin-scale indicators, the PDO, the NPGO, and the ENSO-MEI, all changed phase at some point during the winter of 2013/14. The PDO changed to positive values, indicative of warmer waters in the North Pacific; the NPGO to negative values, indicative of lower productivity along the coast; and the MEI to positive values, indicative of an oncoming El Nino. Whereas the majority of the California Current system appears to have transitioned to an El Nino state by August 2014, based on decreases in upwelling and chlorophyll a concentration, and increases in SST, there still remained pockets of moderate upwelling, cold water, and high chlorophyll a biomass at various central coast locations, unlike patterns seen during the more major El Ninos (e.g., the 97-98 event). Catches of rockfish, market squid, euphausiids, and juvenile sanddab remained high along the central coast, whereas catches of sardine and anchovy were low throughout the CCS. 2014 appears to be heading towards a moderate El Nino state, with some remaining patchy regions of upwelling-driven productivity along the coast. Superimposed on this pattern, three major regions have experienced possibly non-El Nino-related warming since winter: the Bering Sea, the Gulf of Alaska, and offshore of southern California. It is unclear how this warming may interact with the predicted El Nino, but the result will likely be reduced growth or reproduction for many key fisheries species.

Few fisheries oceanography surveys in the United States have sampled hydrography and ichthyoplankton or juvenile fishes for 15 years or more. We describe six long time series surveys, including three from the California Current System, and one each from Alaska (Gulf of Alaska, Bering Sea, and the Arctic), the Northeast US Shelf, and the Gulf of Mexico. We examine the applications of long time series data as well as the output of published analyses, Web-based graphical summaries, and quality controlled data to the broader scientific community (including resource managers and stakeholders). Potential improvements to the surveys using new technologies are evaluated, and possible changes in survey design are discussed. We conclude with a summary of the benefits derived from these long time series fisheries oceanography surveys and make the case for their continuation.