A delay-differential model for representing small pelagic fish stock dynamics and its application for assessing alternative management strategies under environmental uncertainty

We present a novel adaptation of the classic discrete delay-difference model, a continuous delay-differential model (cDDM), which can adequately represent population dynamics of stocks that turn over rapidly and continuously over time (e.g., small pelagic fish, small tunas, and shrimps). We used the Northern-Central Peruvian anchoveta stock (Engraulis ringens, Engraulidae) as a case study for implementing the cDDM and conducted a management strategy evaluation (MSE) through stochastic optimization in policy space (SOPS). Our results showed that cDDM integrated with SOPS efficiently searches optimum and near-optimum harvest control rules (HCR) and is an alternative to pre-setting arbitrary HCRs as in traditional MSE. The cDDM showed comparable stock biomass and recruitment estimate reconstructions to more complex stock assessment models described for anchoveta. We concluded that the anchoveta stock is sustainably managed and is an example of adaptive fisheries management under high ocean-climate variability and uncertainty. Contrary to fishery textbooks, the anchoveta's collapse was not entirely due to the 1972 El Niño (EN) but a recruitment failure preceding EN. Our reconstructions revealed that low recruitment (or recruitment failure) could still occur at high stock biomass. Anchoveta's stock biomass is larger than pre-collapse, likely due to favourable environmental conditions (a cooling trend) and management, despite more frequent and stronger EN events. SOPS quickly revealed that harvest strategies with large base biomass (>5 mmt) lead to higher interannual stock variability and would not produce substantial increases in long-term yield. Alternative HCRs with lower base biomass, while adjusting for productivity regimes, have similar long-term yields without affecting the long-term average stock.     

Population dynamics of the exploited sea cucumber Isostichopus fuscus in the western Galápagos Islands, Ecuador

Long-term density data for the sea cucumber, Isostichopus fuscus, from Canal Bolivar (separating western Isabela and eastern Fernandina Islands), Galápagos, were compared with catch statistics and used in a stock depletion model to determine the extent of the effects of the fishery on the existing population and the potential for the population to recover after each fishing season. Recruitment indices were found to be low from 1994 until mid-1999, when a mass recruitment event was registered and numbers of small individuals increased dramatically. The increase in density of juveniles peaked in 2001 and has declined since. Recruitment in this species of sea cucumber appears to be highly sporadic and may depend on intense climatic events such as the warm El Niño. Current levels of fishing activity are unsustainable. The management implications of pulse recruitment in this fishery are discussed.     

Seasonal and interannual variations of oceanographic conditions off Mangalore coast (Karnataka, India) in the Malabar upwelling system during 1995–2004 and their influences on the pelagic fishery

Mangalore coast is well known for its multi‐species and multi‐gear fisheries and the fishery and oceanographic features of this region is a true representation of the Malabar upwelling system. Ten years of study (1995–2004) of oceanographic parameters has been carried out from the inshore waters off Mangalore to understand their seasonal and interannual variations and influences on the pelagic fishery of the region. Attempt has been also made to understand the influence of local and global environmental conditions on the alternating patterns of abundance between the Indian mackerel and oil sardine from the area. Field‐ and satellite‐derived oceanographic data have shown that coastal upwelling occurs during July–September with a peak in August resulting in high nutrient concentrations and biological productivity along the coast. Nearly 70% of the pelagic fish catch, dominated by oil sardine and mackerel, was obtained during September–December, during or immediately after the upwelling season. Catches of scombroid fishes were significantly related to cold Sea Surface Temperature, while such relationships were not observed for sardines and anchovies. Significant positive correlations were observed between the ENSO events (MEI) and seawater temperature from the study area. The extreme oceanographic events associated with the cold La Niña, which preceded the exceptional 1997–98 El Niño event, were responsible for the collapse of the pelagic fishery, especially the mackerel fishery along the southwest coast of India (Malabar upwelling system). Coinciding with the collapse of the mackerel fishery, oil sardine populations revived during 1999–2000 all along the southwest coast of India. Tolerance of oil sardine to El Niño / La Niña events and the low predatory pressure experienced by their eggs and larvae due to the collapse of mackerel population might have resulted in its population revival.     

Impact of spring upwelling variability off southern‐central Chile on common sardine (Strangomera bentincki) recruitment

Off southern‐central Chile, the impact of spring upwelling variability on common sardine (Strangomera bentincki) recruitment was examined by analyzing satellite and coastal station winds, satellite chlorophyll, and common sardine recruitment from a stock assessment model. In austral spring, the intensity of wind‐driven upwelling is related to sea surface temperature (SST) from the Niño 3.4 region, being weak during warm periods (El Niño) and strong during cold periods (La Niña). Interannual changes in both spring upwelling intensity and SST from the Niño 3.4 region are related to changes in remotely sensed chlorophyll over the continental shelf. In turn, year‐to‐year changes in coastal chlorophyll are tightly coupled to common sardine recruitment. We propose that, in the period 1991–2004, interannual changes in the intensity of spring upwelling affected the abundance and availability of planktonic food for common sardine, and consequently determined pre‐recruit survival and recruitment strength. However, the importance of density‐dependent factors on the reproductive dynamic cannot be neglected, as a negative association exists between spawning biomass and recruitment‐per‐spawning biomass. Coastal chlorophyll, upwelling intensity, and SST anomalies from the Niño 3.4 region could potentially help to predict common sardine recruitment scenarios under strong spring upwelling and El Niño Southern Oscillation (ENSO)‐related anomalies.     

Qualitative modelling for the development of a sustainable management strategy for the Peruvian scallop Argopecten purpuratus (Lamarck 1819)

• 1. This study is the first attempt using Levins's Theory (loop analysis) in order to develop a sustainable management for the scallop, Argopecten purpuratus, fishery in Peru during El Niño‐Southern Oscillation events (ENSO) and upwelling conditions. Based on this theoretical framework, it was possible to estimate the local stability for each of these model systems and to follow the qualitative changes of the variables in response to external factors.
• 2. Based on our results, we suggest the following management policies to be implemented: (1) during ENSO events the size at the first capture of the scallops should be >70 mm and (2) the increase in the number of fishermen during ENSO events must be prevented. Both measures increase the sustainability of fishery under ENSO and upwelling conditions. The ecological models predict that during ENSO and upwelling events, any management strategy to increase the recruitment of the scallop would not have a positive impact on the adult stock.
• 3. Finally, we suggest that more efforts must be focused on the development of extended eco‐social models, which incorporate further social and economic variables, increasing realism of the abstractions for this fishery activity.

Copyright © 2002 John Wiley & Sons, Ltd.     

From small-scale habitat loopholes to decadal cycles: a habitat-based hypothesis explaining fluctuation in pelagic fish populations off Peru

The Peru‐Humboldt Current system (HCS) supports the world's largest pelagic fisheries. Among the world's eastern boundary current systems, it is the most exposed to high climatic stress and is directly affected by El Niño and La Niña events. In this volatile ecosystem, fish have been led to develop adaptive strategies in space and time. In this paper, we attempt to understand the mechanisms underlying such strategies, focusing on the El Niño 1997–98 in Peru from which an extensive set of hydrographic, capture and acoustic survey data are available. An integrated analysis of the data is crucial, as each has substantial shortcomings individually; for example, both catch data and acoustic surveys may easily lead to wrong conclusions. Existing hypotheses on anchovy and sardine alternations lead us to a ‘habitat‐based’ synthetic hypothesis. Using our data, an integrated approach evaluated how fish responded to habitat variation, and determined the consequences in terms of fish‐population variability. Various factors occurring at a range of different spatio‐temporal scales were considered: interdecadal regime (warm ‘El Viejo’/cool ‘La Vieja’ decadal scale); strength and the duration of the El Niño Southern Oscillation event (interannual scale); population condition before the event (interannual scale); fishing pressure and other predation (annual scale); changes in reproductive behaviour (intra‐annual scale); presence of local upwelling (local scale). During El Niño 1997–98, anchovy was able to exploit a small‐scale temporal and spatial ‘loophole’ inside the general unfavourable conditions. Moreover, sardine did not do better than anchovy during this El Niño and was not able to take advantage of the ‘loophole’ opened by this short‐term event. Our results question the traditional view that El Niño is bad for anchovy and good for sardine.     

El Niño effects in the Palmyra Atoll region: oceanographic changes and bigeye tuna (Thunnus obesus) catch rate variability

A generalized additive model (GAM) was constructed to separate and quantify the effects of fishery‐based (operational) and oceanographic parameters on the bigeye tuna (Thunnus obesus) catch rates at Palmyra Atoll in the central Tropical Pacific. Bigeye catch, the number of hooks per set, and set location from 4884 longline sets spanning January 1994 to December 2003 were used with a temporally corresponding El Niño‐Southern Oscillation (ENSO) indicator built from sea surface height (SSH) data. Observations of environmental data combined with the results from the GAM indicated that there is an increase in bigeye catch rates corresponding to an increase in eastward advection during the winter months of El Niño events. A seasonal pattern with higher bigeye catch rates from December to April and a spatial pattern with higher rates to the northeast and northwest of the atoll were observed during this study period. It is hypothesized that the combination of the eastward advection of the warm pool coupled with vertical changes in temperature during the winter months of El Niño events increases the availability of bigeye tuna in this region. This increase in availability may be due to a change in exploitable population size, location, or both.     

Distribution of whale shark (Rhincodon typus) off northern Peru based on habitat suitability

1. In the south‐eastern Pacific Ocean, few studies of whale sharks (Rhincodon typus) exist. In Peru, the northern coast has been identified as the area with the highest presence of whale sharks, yet their ecology in this area is poorly defined.
2. This study predicts the spatial distribution of whale sharks off coastal northern Peru (03°00′S–04°30′S) during La Niña and El Niño seasonal conditions, utilizing maximum entropy modelling. Between 2009 and 2018 (except for 2011), 347 whale sharks were geo‐referenced in northern Peru with greatest data recordings in the austral summer and spring during La Niña events.
3. Depth was the most important predictive variable for spatial distribution of whale sharks, followed by chlorophyll‐a. Sharks were predicted in shallower coastal waters in which chlorophyll‐a values are higher.
4. Habitat suitability was higher in the northern coastal part of the study area. Spring presents the most suitable environmental conditions for whale sharks, both during La Niña and El Niño conditions. The probability of whale shark presence in the north of Peru increases at higher chlorophyll‐a and sea surface temperature values. Therefore, whale sharks appear to aggregate seasonally in northern Peru, potentially exploiting rich foraging grounds.
5. In these areas of high suitability, whale sharks are susceptible to fisheries, bycatch, ship collisions, unmanaged tourism, and pollution; thus, management actions should focus in these areas.
6. This study represents a first step to understand the distribution and habitat suitability of whale shark in Peruvian waters. Further studies should identify suitable habitat for whale sharks in offshore areas. Also, these should focus on the connectivity of these aggregations with other localities in the south‐eastern Pacific in order to contribute to regional strategies for the conservation of this iconic species in this particular region.

     

Anchovy distribution off Peru in relation to abiotic parameters: A 32‐year time series from 1985 to 2017

Oceanographic and hydroacoustic data were obtained by the Instituto del Mar del Peru (IMARPE) during 72 cruises off the Peruvian coast between 1985 and 2017 to determine the ranges of the abiotic parameters influencing the anchovy (anchoveta) distribution and to observe the effect of the 1997–1998 El Niño event. The hydroacoustic data show a high seasonal variability in anchoveta distribution related to differences of environmental parameters as well as changes in distribution after the very strong El Niño event in 1997–1998. Geostatistic variograms were used to describe the seasonal variability and generalized additive models (GAMs) with a Tweedie distribution were applied to study the relationships between anchoveta and oceanographic parameters. The dependent variable was the value for anchoveta obtained from echosounder (nautical area scattering coefficient [NASC] of anchoveta) and the tested covariates were temperature, salinity, and dissolved oxygen at the sea surface; distance to the coast; year, latitude–longitude; and Oceanic Niño Index 1 + 2. The results show a high variability of anchoveta with seasonal differences in its distribution. Preferred abiotic conditions (temperature, salinity, oxygen) of anchoveta were 17.6–23.7°C, 32.30–35.14, and 5.9–8.7 ml/L in summer and 14.5–18.8°C, 34.81–35.12, and 5.2–6.3 ml/L in winter. The values in autumn and spring were intermediate and are considered as in transition. The anchoveta were detected at higher values after the 1997–1998 El Niño event, probably influenced by reduced standing stocks of congener fish species and by the Pacific decadal oscillation (PDO) or by a changes in climate.     

Juvenile chinook salmon (Oncorhynchus tshawytscha) growth on the central California coast during the 1998 El Niño and 1999 La Niña

We assessed growth in subyearling chinook salmon (Oncorhynchus tshawytscha) during the 1998 El Niño and 1999 La Niña in the Gulf of the Farallones, a region of the continental shelf off central California seaward of the Golden Gate and the southernmost ocean entry point for the species in North America. Juvenile salmon demonstrated greater growth during this strong El Niño, when water temperature anomalies of more than +3°C were recorded at local buoys, than during the similarly strong 1999 La Niña. Slopes of regressions of weight on length, length on age, and weight on age were all significantly greater for juvenile salmon during the 1998 El Niño compared with those in the 1999 La Niña. Daily otolith increment widths, an estimator of somatic growth, corroborated population data. Between June 1 and August 9, mean increment widths for juvenile chinook salmon in 1998 were 3.54 ± 0.03 μm, significantly larger than the 3.13 ± 0.03 μm found in juveniles during the same time interval in 1999. Condition factor for juvenile chinook salmon entering the ocean at the Golden Gate was the same in both years, but became significantly greater in ocean fish during the 1998 El Niño than in ocean fish during the 1999 La Niña. Energy storage was significantly greater in ocean juvenile salmon during the 1998 El Niño as well. Mean triacylglycerol/cholesterol ratios increased following ocean entry in 1998, whereas they declined in ocean juveniles during 1999. Thus, not only was growth better in the El Niño period compared with La Niña, but lipid accumulation was also better. Oceanographic data for 1998 indicated elevated temperatures, lower salinity, greater freshwater outflow from San Francisco Bay, northerly flowing coastal currents, and positive upwelling index anomalies. This combination of environmental factors resulted in greater zooplankton productivity that, in conjunction with higher temperatures, allowed metabolic processes to enhance growth. Although El Niño events have certainly produced large-scale, and often adverse, effects on ecosystems, the results of this study emphasize the importance of local oceanographic conditions to growth and other physiological and ecological processes.     

Impact of short‐term climate effects and sea ice coverage variation on Japanese scallop aquaculture in Saroma Lake,Japan

Saroma Lake is the southernmost lagoon exhibiting seasonal sea ice coverage in the Northern hemisphere and one of the most important aquaculture areas for Japanese scallops (Mizuhopecten yessoensis). Under conditions of adequate food and appropriate temperature, scallops grow well from the time of ice melting in April to harvesting starting in July. However, over the past decade, Saroma Lake frequently has not been completely covered by ice in winter, and the production of Japanese scallops has shown significant changes. Therefore, this study integrated data from satellite remote sensing, buoys, and in situ observations with climatic events [the winter East Asian Monsoon (EAM) and El Niño/La Niña–Southern Oscillation events] to investigate the impact of ice coverage variations on scallop growth in Saroma Lake between 2007 and 2015. Daily ice conditions were detected using Moderate Resolution Imaging Spectroradiometer false colour images and an unsupervised classification method. The results indicated that EAM strongly influenced the ice coverage variation in Saroma Lake through their effects on temperature during winter. Ice coverage variations show a strong correlation with water temperature and spring phytoplankton blooms, which are the two most important environmental factors for scallop growth. In addition, extreme climate events could cause water temperature anomalies (as in 2015) which are unfavourable for scallop growth. Monitoring ice conditions should be considered when developing plans and management strategies for scallop aquaculture in Saroma Lake.     

Mesopelagic fish larval assemblages during El Niño‐southern oscillation (1997–2001) in the southern part of the California Current

Mesopelagic species are the principal constituents of larval fish assemblages inhabiting the southerly California Current region. Seasonal larval abundance is influenced by circulation of the California Current and subtropical Countercurrent, including regional changes of the physical, chemical, and biological characteristics during the El Niño‐Southern Oscillation. This study examines the mesopelagic fish larvae distribution and abundance patterns between seasons and years, with the aim of describing the mesopelagic larval assemblages during dynamic environmental changes induced by El Niño (1997–1998) and the rapid transition to La Niña (1998–2000) along the west coast of the Baja California Peninsula (25–31°N). Despite large oceanographic variability, larval assemblages varied principally on a seasonal basis, related to reproductive periods and the north–south gradient influenced by the seasonal pattern of the California Current. An increased diversity, number of species, and abundance of tropical species was noticeable during the northward expansion of warm‐water taxa during El Niño, principally in the northern areas (Ensenada and Punta Baja). After El Niño, population adjustments and rapid recovery occurred during La Niña conditions, which reflected seasonal differences in the mesopelagic community structure that are closely related to the seasonal pattern of oceanic currents.     

El Niño–Southern Oscillation impacts on jumbo squid habitat: Implication for fisheries management

1. Dosidicus gigas is an ecologically and economically important squid species extensively distributed in the eastern Pacific Ocean. Its habitat is extremely sensitive to climatic and environmental variability.
2. The relationship between habitat pattern of D. gigas and El Niño–Southern Oscillation (ENSO, divided into the El Niño, ENSO-neutral, and La Niña events) was assessed from 1950 to 2015, using a habitat suitability index (HSI) modelling approach including two crucial environmental variables: sea surface temperature (SST) and sea surface height anomaly (SSHA).
3. On the basis of cross-correlation analysis, it showed that both SST anomaly and SSHA were significantly positively related to the ENSO index. Moreover, a significantly negative association was found between the HSI values and the ENSO index.
4. Due to the El Niño events, SST off Peru became higher and sea level rose, resulting in contracted areas of suitable SST and SSHA; consequently, suitable habitats for D. gigas dramatically decreased. In contrast, during the ENSO-neutral and La Niña years, the extent of suitable SST and SSHA increased due to the colder water and lower sea level, and suitable habitat for D. gigas expanded.
5. Moreover, the latitudinal gravity centre of HSI was significantly positively associated with the ENSO index. Relative to the ENSO-neutral and La Niña years, a southward movement of the monthly preferred SST isotherm for D. gigas during the El Niño years could explain the occurrence of more suitable habitats in southern waters off Peru.
6. These findings suggested that the ENSO event plays an important role in regulating environmental conditions off Peru and further affected the spatio-temporal distribution of D. gigas habitat.

     

The influence of the El Niño Southern Oscillation on paralarval market squid (Doryteuthis opalescens)

California market squid (Doryteuthis opalescens) support one of the largest and most valuable fisheries in California. However, market squid abundance varies greatly from year to year, ostensibly as a result of the El Niño Southern Oscillation (ENSO) phenomenon, although the underlying mechanism is not known. Classic hypotheses suggest that the early larval stage may be the key to uncovering this mechanism. Here, we perform a time series analysis, length‐distribution analysis, and growth analysis to investigate the effects of ENSO on paralarval D. opalescens. In contrast to classic hypotheses, we find that ENSO does not drive early paralarval survival or growth. Instead, we find that the ENSO operates primarily on the late paralarval stage, with El Niño conditions associated with lower survival of late‐stage paralarvae. We also find that time series models which use ENSO conditions during the previous juvenile and adult stage outperform models that use ENSO conditions during the paralarval stage. Our results suggest that the population bottleneck for D. opalescens does not occur in the early paralarval stage, but instead lies later in the squid's life.     

The demography of Calanus pacificus during winter–spring Californian El Niño conditions, 1992–1993: implications for anchovy?

Samples from the southern California sector of the California Current System were examined to test for changes in abundance, reproduction, recruitment and naupliar survival of the planktonic copepod, Calanus pacificus, coincident with the 1993 Californian El?Niño, relative to 1992 (also El Niño conditions) and to 1989–1991 (defined as `normal'). In 1993, as in 1992, females were rare in both winter and spring, but per capita reproduction was less, food limitation was greater and biomass of chlorophyll was reduced only in winter. Recruitment was more variable than was naupliar survival. Recruitment increased in both El Niño springs, but survival of older naupliar stages decreased. The mesoscale distributions of larval anchovy, relative to eggs and nauplii of Calanus, did not result in efficient use of the reduced supply of this source of food, and the abundance of larval anchovy did not cause measurable variation in the survival of naupliar Calanus.     

Environmental associations of Pacific bluefin tuna (Thunnus orientalis) catch in the California Current system

We investigate the impact of oceanographic variability on Pacific bluefin tuna (Thunnus orientalis: PBF) distributions in the California Current system using remotely sensed environmental data, and fishery‐dependent data from multiple fisheries in a habitat‐modeling framework. We examined the effects of local oceanic conditions (sea surface temperature, surface chlorophyll, sea surface height, eddy kinetic energy), as well as large‐scale oceanographic phenomena, such as El Niño, on PBF availability to commercial and recreational fishing fleets. Results from generalized additive models showed that warmer temperatures of around 17–21°C with low surface chlorophyll concentrations (<0.5 mg/m³) increased probability of occurrence of PBF in the Commercial Passenger Fishing Vessel and purse seine fisheries. These associations were particularly evident during a recent marine heatwave (the “Blob”). In contrast, PBF were most likely to be encountered on drift gillnet gear in somewhat cooler waters (13–18°C), with moderate chlorophyll concentrations (0.5–1.0 mg/m³). This discrepancy was likely a result of differing spatiotemporal distribution of fishing effort among fleets, as well as the different vertical depths fished by each gear, demonstrating the importance of understanding selectivity when building correlative habitat models. In the future, monitoring and understanding environmentally driven changes in the availability of PBF to commercial and recreational fisheries can contribute to the implementation of ecosystem approaches to fishery management.     

A study on relationships between large‐scale climate indices and estimates of North Pacific albacore tuna productivity

A logistic production model was used to examine potential relationships between three climate indices, the North Pacific Gyre Oscillation (NPGO), the Pacific Decadal Oscillation (PDO), and the Multivariate El Niño‐Southern Oscillation Index (MEI), and productivity estimates of the North Pacific albacore tuna (Thunnus alalunga) population. Catch and standardized catch‐per‐unit‐effort data from three longline fisheries (Japan, US, and Taiwan) were used in the model. The climate indices were incorporated into the model by correlating time‐varying intrinsic population growth rate (r_y) of the production model with the annual mean value for each index. The estimated probability that the NPGO is positively correlated with stock productivity, as measured by r_y, was 0.99, and the calculated probability that MEI is negatively correlated with the productivity was 0.95. The time lag for these correlations is 4 yr, which is consistent with the timing of recruitment to the Japan longline fishery. The PDO did not seem to have any detectable relationship with stock productivity. However, it remains uncertain if there is a conclusive linkage between the albacore productivity and the NPGO or the MEI index, because model fit to the data is about the same as that of a base model which does not use any climate index and assumes a time‐invariant r.     

Differing environmental drivers of settlement across the range of southern rock lobster (Jasus edwardsii) suggest resilience of the fishery to climate change

Temporal and spatial trends in settlement of the southern rock lobster, Jasus edwardsii, were examined to identify the influence of environmental variables over different spatial scales. Settlement data were collected from 1994 to 2011 along the Southern Australian and New Zealand coasts. We identified common settlement trends at a regional scale (100–500 km): the magnitude of settlement at sites from South Australia (SA) and Victoria (VIC) were similar, but different to sites in Tasmania (TAS). In New Zealand, three spatial regions were identified: northern (NNZ), middle (MNZ) and southern regions (SNZ). Higher settlement in SA, VIC and MNZ occurred in years with higher rainfall and storms in spring and El Niño conditions. In TAS and SNZ, higher settlement occurred during La Niña conditions. These results suggest that settlement over regional scales is modulated by oceanic processes, but outcomes vary between regions. At a local scale, a higher wave period and wind relaxation were relatively more important than the sea surface temperature (SST) in SA and VIC. In TAS, the current velocity also influenced the strength of settlement. However, much of the local settlement variability was not explained by the models suggesting that settlement in J. edwardsii is a complex process where larval behaviour, biological factors and oceanographic processes interact over different scales. The apparently complex processes affecting settlement showed that environmental conditions that reduced settlement strength in one region of the fishery often increased settlement strength in other regions. This could provide resilience to climate change at the stock level.     

Interannual variation in pelagic juvenile rockfish (Sebastes spp.) abundance – going with the flow

We report results from 28 yr of a midwater trawl survey of pelagic juvenile rockfish (Sebastes spp.) conducted off the central California coast. The fishery‐independent survey is designed to provide pre‐recruit indices of abundance for use in groundfish stock assessments. Standardized catch rate time series for 10 species were developed from delta‐generalized linear models that include main effects for year, station, and calendar date. Results show that interannual fluctuations of all 10 species are strongly coherent but highly variable, demonstrating both high‐ and low‐frequency components. A similarly coherent result is observed in the size composition of fish, with large fish associated with elevated catch rates. In contrast, spatial and seasonal patterns of abundance show greater species‐specific differences. A comparison of the shared common trend in pelagic juvenile rockfish abundance, derived from principal components analysis, with recruitments from five rockfish stock assessments shows that the time series are significantly correlated. An examination of oceanographic factors associated with year‐to‐year variability indicates that a signature of upwelled water at the time of the survey is only weakly related to abundance. Likewise, basin‐scale indices (the Multivariate El Niño‐Southern Oscillation Index, the Pacific Decadal Oscillation, the North Pacific Gyre Oscillation, and the Northern Oscillation Index) are poorly correlated with abundance. In contrast, sea level anomalies in the months preceding the survey are well correlated with reproductive success. In particular, equatorward anomalies in the alongshore flow field following the spawning season are associated with elevated survival and poleward anomalies with poor survival.