Life-history traits of Pacific ( Clupea pallasii ) and Atlantic ( Clupea harengus ) herring, comprising both local and oceanic stocks subdivided into summer-autumn and spring spawners, were extensively reviewed. The main parameters investigated were body growth, condition, and reproductive investment. Body size of Pacific herring increased with increasing latitude. This pattern was inconsistent for Atlantic herring. Pacific and local Norwegian herring showed comparable body conditions, whereas oceanic Atlantic herring generally appeared stouter. Among Atlantic herring, summer and autumn spawners produced many small eggs compared to spring spawners, which had fewer but larger eggs—findings agreeing with statements given several decades ago. The 26 herring stocks we analysed, when combined across distant waters, showed clear evidence of a trade-off between fecundity and egg size. The size-specific individual variation, often ignored, was substantial. Additional information on biometrics clarified that oceanic stocks were generally larger and had longer life spans than local herring stocks, probably related to their longer feeding migrations. Body condition was only weakly, positively related to assumingly in situ annual temperatures (0–30 m depth). Contrarily, body growth (cm × y −1 ), taken as an integrator of ambient environmental conditions, closely reflected the extent of investment in reproduction. Overall, Pacific and local Norwegian herring tended to cluster based on morphometric and reproductive features, whereas oceanic Atlantic herring clustered separately. Our work underlines that herring stocks are uniquely adapted to their habitats in terms of trade-offs between fecundity and egg size whereas reproductive investment mimics the productivity of the water in question.

In this proof‐of‐concept study, we show how satellite remote sensing can be used to detect and monitor Pacific herring spawning events in the Strait of Georgia (SoG), British Columbia, Canada. Multi‐sensor medium‐resolution (∼300 m) and high‐resolution (3–30 m) images reveal bright waters in the SoG due to high concentrations of herring milt from multiple spawning events. The milt‐infused waters lead to enhanced reflectance with unique spectral characteristic that can be distinguished from other optically active constituents such as suspended sediments, coccolithophores, “whiting” particles, and shallow bottoms. While the medium‐resolution images may be used to search for cloud‐free and potential spawning sites, high‐resolution images show more details in milt distributions. Given the increased availability of high‐resolution satellite imagery at the global scale, this demonstration may promote more applications of satellite remote sensing in fisheries and ocean ecology research.

Pacific and Atlantic herring populations (genus Clupea) commonly experience episodic collapse and recovery. Recovery time durations are of great importance for the sustainability of fisheries and ecosystems. We collated information from 64 herring populations to characterize herring fluctuations and determine the time scales at low biomass and at high and low recruitment, and use generalized linear models and Random Survival Forests to identify the most important bottom-up, top-down and intrinsic factors influencing recovery times. Compared to non-forage fish taxa, herring decline to lower minima, recover to higher maxima and show larger changes in biomass, implying herring are more prone to booms and busts than non-forage fish species. Large year classes are more common in herring, but occur infrequently and are uncorrelated among regionally grouped stocks, implying local drivers of high recruitment. Management differs between Pacific and Atlantic herring fisheries, where at similarly low biomass, Pacific fisheries tend to be closed while Atlantic fisheries remain open. This difference had no apparent effect on herring recovery times, which averaged 11 years, although most stocks with longer recovery periods had not yet recovered at the end of the observation period. Biomass recovery is best explained by median recruitment and variability in sea surface height anomalies and sea surface temperatures-higher variability leads to shorter recovery times. In addition, the duration of recruitment failure is closely linked with low biomass. While recovery times rely on the nature of the relationship between spawning biomass and recruitment, they are still largely governed by complex and uncertain processes.

Age-specific declines in length and weight of Pacific herring occurred in all coastal areas of British Columbia (BC) from approximately 1985 to 2010, followed by a more recent reversal in that trend. Concurrent with declining age-specific size, the number of egg layers deposited on vegetation, as estimated from diver surveys, declined but recently this trend also has reversed. In most areas egg layers declined by half, or more, of pre-decline estimates, from means of about 2-3 layers to about 0.5-1 layers. In general, as egg density declined, no corresponding reductions occurred in other metrics of herring spawning such as the mean length or width of the spawning bed. Correlation analyses indicate that the coherence of these two independently measured trends (declining size-at-age and declining egg density) is highly significant (p << 0.01) in all REGIONs of the BC coast. We briefly examine two of several potential biological explanations for these temporal changes: (1) size-dependent ovary size; (2) size-dependent packing density of spawning fish. Quantitative estimates of herring spawn deposition are integral to herring spawning stock biomass assessments in BC and elsewhere so it is important to understand the factors that affect egg density. Our analyses indicate that changes in herring growth or 'size-at age', which probably reflect regional warming related to climate change, can subsequently impact parameters of reproduction and spawning behaviour.

Small pelagic fish are key planktivores and prey in marine ecosystems, and their population abundances undergo strong temporal and spatial variability. Top-down (predator controlled) and bottom-up (prey-driven) processes during early life history are important for determining forage fish survival and recruitment. We examined biological and environmental factors hypothesized to influence age-0 Pacific herring Clupea pallasi in the Strait of Georgia (SOG), British Columbia, Canada. Primarily bottom-up processes affected interannual variability in age-0 herring abundance and condition, with some evidence of top-down effects on condition. Age-0 herring abundance increased with increasing adult spawning biomass and peaked when most adults spawned about 20 d prior to the peak spring primary production bloom. This timeline would temporally align first-feeding herring larvae with their prey, such as small copepods. Age-0 herring abundance also increased with increasing juvenile salmon abundance, indicating that conditions favourable for herring were also favourable for their predators and competitors. Age-0 herring condition decreased with increasing spawning biomass, increased when most adults spawned closer to the peak spring bloom, increased with increasing temperatures above 8.2°C, and increased then stabilized with increasing prey zooplankton density. Age-0 herring condition had a dome-shaped relationship with predator abundance, indicating that high predator abundances negatively affected fish condition. Study results suggest that density-dependent processes, such as intraspecific competition, may be important in the SOG. A positive correlation between age-0 herring abundance and subsequent age-3 recruit abundance may provide a leading indicator of low recruitment years.

Many small pelagic fish species exhibit dramatic fluctuations in abundance accompanied by range expansions during periods of favorable environmental conditions. The location and extent of suitable habitats also shift in response to both short term variability and long term trends in climate. Near the margins of a contemporary range, trends in abundance may reflect a continuation of historical variability but may also foreshadow future changes in distribution. The Salish Sea (all inland marine waters of Washington State and southern British Columbia; made up of the Strait of Georgia, Strait of Juan de Fuca, and Puget Sound) is a highly productive estuarine system at the northern end of the distribution of Northern Anchovy (Engraulis mordax). An apparent recent (2014–2016) increase in Northern Anchovy abundance has generated interest in the dynamics of this species in the Salish Sea. We compiled recent and historical data to understand spatiotemporal patterns of distribution and fluctuations in abundance over the last century. Spatially-consistent occurrence of eggs, larvae, and juveniles, and year-round presence of multiple age classes, confirm that successful spawning and recruitment of Northern Anchovy occurs within the Salish Sea. Most periods of elevated Northern Anchovy abundance in the last century have corresponded to, or lagged, periods of elevated ocean temperatures. While a 2005 peak in abundance within the Salish Sea also corresponded to higher abundance of Northern Anchovy in adjacent regions of the coastal Pacific Ocean, it seems unlikely that Salish Sea abundance is controlled primarily by advection or migration from external populations. Persistence of elevated ocean temperatures like those observed from 2014 to 2016 could lead to consistently high abundance of Northern Anchovy within the Salish Sea, with implications for trophic relationships and ecosystem function.

Pacific herring are important to fisheries and trophic interactions in the California Current Ecosystem (CCE). In this paper we test the hypothesis that herring biomass across the ecosystem has declined over the past three decades. Overall, herring spawning stock biomass has decreased since the mid to late 1980s, though some populations at the local to regional scale appear stable or have even increased. For regional populations in the northern CCE studied over a much longer time period (six decades), cyclic patterns of abundance are evident, suggesting that the shorter-term trend may be part of a longer-term, Pacific Decadal Oscillation (PDO)-scale cycle. In the southern part of the herring range (California and Oregon), population fluctuations are increasing, which may be related to increasing climate variability there (Sydeman et al. 2013; Black et al. 2014). Large-scale trophic mechanisms to local distribution shifts are implicated in metapopulation fluctuations. Future abundance assessments for herring in the CCE should address how climate and fisheries may synergistically impact populations.

Pacific herring populations at eight North Pacific Rim locations were simulated to compare basin-wide geographic variations in age-specific growth due to environmental influences on marine productivity and population-specific responses to regime shifts. Temperature and zooplankton abundance from a three-dimensional lower-trophic ecosystem model (NEMURO: North Pacific Ecosystem Model for Understanding Regional Oceanography) simulation from 1948 to 2002 were used as inputs to a herring bioenergetics growth model. Herring populations from California, the west coast of Vancouver Island (WCVI), Prince William Sound (PWS), Togiak Alaska, the western Bering Sea (WBS), the Sea of Okhotsk (SO), Sakhalin, and Peter the Great Bay (PGB) were examined. The half-saturation coefficients of herring feeding were calibrated to climatological conditions at each of the eight locations to reproduce averaged size-at-age data. The depth of averaging used for water temperature and zooplankton, and the maximum consumption rate parameter, were made specific to each location. Using the calibrated half-saturation coefficients, the 1948-2002 period was then simulated using daily values of water temperature and zooplankton densities interpolated from monthly model output. To detect regime shifts in simulated temperatures, zooplankton and herring growth rates, we applied sequential t-test analyses on the 54 years of hindcast simulation values. The detected shifts of herring age-5 growth showed closest match (69%) to the regime shift years (1957/58, 1970/71, 1976/77, 1988/89, 1998/99). We explored relationships among locations using cluster and principal component analyses. The first principal component of water temperature showed good correspondence to the Pacific Decadal Oscillation and all zooplanIcton groups showed a pan-Pacific decrease after the 1976/77 regime shift. However, the first principal component of herring growth rate showed decreased growth at the SO, PWS, WCVI and California locations and increased growth at the Sakhalin, WBS and Togiak locations after 1977. The SO location belonged to the same cluster as the location in with the eastern North Pacific. The calibrated half-saturation coefficients affected the degree to which growth was sensitive to interannual variation in water temperature versus zooplankton. For example, the half-saturation values for the SO location resulted in very efficient feeding that shifted the sensitivity of herring growth from food to temperature. The model results demonstrate how geographic specificity of bioenergetics parameters, coupled with location-specific variation in temperature and food, can combine to determine local and regional responses of fish growth to climate forcing. (C) 2015 Elsevier Ltd. All rights reserved.

In laboratory tests young Pacific herring (Clupea harengus pallasi) larvae were eaten by several species of hydromedusae common in coastal waters off British Columbia, including the previously controversial Sarsia tubulosa and by the scyphomedusa Aurelia aurita. Field collections and observations confirmed that the distributions of medusae and larvae overlap and that some medusae feed on herring larvae in nature. In coastal waters and bays of British Columbia, the hydromedusae Sarsia tubulosa or Aequorea victoria may be most abundant during the time of peak herring larvae abundance.Key words: herring, larvae, Clupea, Sarsia, Aequorea, predation, medusae

Hay, D. E., McCarter, P. B., Daniel, K. S., and Schweigert, J. F. 2009. Spatial diversity of Pacific herring (Clupea pallasi) spawning areas. - ICES Journal of Marine Science, 66: 1662-1666.Eastern Pacific herring spawn in intertidal and shallow subtidal areas. Spawning sites are conspicuous: milt turns coastal waters white, sometimes for distances of many kilometres. This attribute has enabled biologists to document spawning distributions for more than 70 years throughout the 29 500 km coastline of western Canada. Spawning distributions and spatial diversity have varied over time. When aggregated over 70 years (1938-2007), spawning occurred along 5574 km or ∼20% of the total coastline. Cumulative annual spawn length ranges from 131 (in 1966) to 770 km (in 1992). We examined annual changes in spawn distribution using spatial units of variable size, ranging in area from a maximum of >1000 km 2 to a minimum of 0.3 km 2 ). The choice of spatial scale can affect the results from analyses of other factors, such as SSB, that could affect spatial diversity of spawning areas.

Within the Strait of Georgia (BC, Canada), recruitment of Pacific herring (Clupea pallasi) to the spawning stock at age 3 can be highly variable, and this component may compose a major portion of the spawning-stock biomass. Therefore, a reliable method of forecasting recruitment strength would be useful for determining total allowable catches for the fishery. We developed an empirical approach to forecasting recruitment from young-of-the-year (YOY) surveys using purse-seine sampling in late September and evaluate its predictive capability for estimating the relative size of a year class before it enters the fishery. For each year, we compared YOY catches-by-weight with the number of age-3 recruits derived from subsequent catch-at-age analyses. The relationship is positive but not statistically significant because of considerable annual variation in the estimates. However, it is worth noting that in years when YOY herring were least abundant, the resulting cohort also was low. Consequently, although the relationship may not be sufficiently precise for accurate recruitment forecasting, it can be used by fishery management for the qualitative evaluation of the likelihood of strong or weak returns in future seasons when setting quotas for the fishery.

We used a nutrient-phytoplankton-zooplankton (NPZ) model coupled to a fish bioenergetics model to simulate the weight-at-age responses of Pacific herring Clupea pallasii to climate regimes. The NPZ model represents the daily dynamics of the lower trophic levels by simulating the uptake and recycling dynamics of nitrogen and silicon and the photosynthesis and grazing interactions of multiple functional groups of phytoplankton and zooplankton. The bioenergetics model simulates the number and mean weight of Pacific herring for each of 10 age-classes. Three zooplankton groups simulated in the NPZ model provide estimates of the prey used to determine the consumption component of the herring bioenergetics model. We used a spawner-recruit relationship to estimate the number of new age-1 individuals joining the herring population every year. The coupled models were applied to the coastal upwelling area off the west coast of Vancouver Island. Model simulations were performed to isolate the effects of each of four documented climate regimes on Pacific herring weights at age. The climate regimes differed in the environmental variables used in the spawner-recruit relationship as well as in the water temperature, mixed-layer depth, and nutrient influxing rate used by the NPZ model. In agreement with general opinion and with the Pacific herring data from the west coast of Vancouver Island, the model-predicted estimates of weight at age, recruitment, and spawning stock biomass were highest in regime 1 (1962-1976), intermediate in regime 2 (1977-1988), and lowest in regime 3 (1989-1999). Insufficient time has passed to adequately document the conditions and herring responses in regime 4 (1998-2002). The overall regime effect on weights at age was a mix of recruitment effects and lower trophic level effects that varied in direction and magnitude among the four regimes. Coupling bioenergetics models to physics and food web models is the next challenge in understanding and forecasting how climate change will affect fish growth and population dynamics.

The infrequent occurrence of climate regime shifts and the long-lived life history of many harvested fish species imply that quantitative understanding of the effects of climate shifts on fish will require long-term data spanning decades. We use the output of the 3-dimensional (3D) NEMURO nutrient–phytoplankton–zooplankton model applied to the Northern Pacific as input to a Pacific herring (Clupea pallasi) bioenergetics model, and predict herring weights-at-age and growth from 1948 to 2000 for the West Coast Vancouver Island (WCVI), Prince William Sound (PWS), and Bering Sea (BS) locations. The feeding parameters of the bioenergetics model were calibrated from steady-state predictions of herring weights-at-age at each location compared to observed mean weights-at-age. Herring weights-at-age were then simulated from 1948 to 2000 using the 3D-NEMURO generated time series of monthly temperature and zooplankton densities. Herring growth rates, annual temperature, and zooplankton density time series were analyzed statistically for coincident shifts in their mean values. We also simulated herring growth rates using the 1948–2000 time series and averaged (climatological) temperature and zooplankton densities to determine the relative importance of temperature and zooplankton to predicted herring growth responses. All three locations showed a shift in herring growth during the mid and late 1970s. Herring growth decreased in WCVI and PWS, and increased in BS; these changes were coincident with a warming of temperature and a decrease in predatory zooplankton density. Herring growth responses in PWS and BS were more complex than those predicted for WCVI, with additional shifts predicted besides the late 1970s shift. Interannual variation in zooplankton densities caused the herring growth response for WCVI. Temperature and zooplankton densities affected the herring growth responses in both Alaskan locations, with zooplankton dominating the response for PWS and temperature dominating the response for BS. We compare our simulated herring growth responses to observed responses, and discuss the advantages and drawbacks of using the output of broadly applied lower trophic model as input to fish models in order to examine long-term responses to regime shifts at multiple locations.

We present a modeling approach where we use one common model formulation of a 11 state variable lower trophic level model that includes two groups of phytoplankton, three groups of zooplankton, and representations of nitrogen and silicate embedded in a three-dimensional ocean general circulation model (OGCM) and forced with a common climate forcing. Results are applied to a fish bioenergetics model for two geographically distinct ocean regions off Japan including the Oyashio, mixed, and Kuroshio subregions and off California including the subarctic, transition and subtropical subregions. The model is applied to two fish species (Pacific saury: Cololabis saira and Pacific herring: Clupea harengus pallasi) with different life histories in each region and the influence of three different “regime shift” periods was explored. With this approach, we narrow the observed biological response and model dynamics to reflect local conditions and eliminate differences related to the model formulations in each region. In general, the trend in temperature was negatively correlated with trends in the zooplankton community. Out-of-phase herring growth trends were observed between the Japan and California regions (r=−0.259, p=0.02). In-phase growth trends between herring and saury were observed at the California region (r=0.61, p<0.01). We did note some evidence of a basin-scale PDO mode response. During 1980–1985, simulated saury and herring in both regions showed a consistent increase in weight-at-age. In the Oyashio subregion, temperature decreased and all three zooplankton groups increased beginning around 1980. The same pattern of a decrease in temperature and an increase in zooplankton densities was observed between 1980 and 1985 in the subarctic subregion of California. Results are discussed in the context of ecosystem-based fisheries management.

We describe an approach to dynamically couple a fish bioenergetics-based population dynamics model to the NEMURO lower trophic level nutrient–phytoplankton–zooplankton model. The coupled models, denoted NEMURO.FISH and configured for Pacific herring (Clupea harengus pallasii) on the west coast of Vancouver Island, are capable of simulating the daily dynamics of the lower trophic levels and the daily average weight and numbers of individual herring in each of 10 age classes over multiple years. New recruits to the herring population are added each June based on either constant recruitment or dynamic recruitment generated from an environmental Ricker spawner–recruitment relationship. The dynamics of the three zooplankton groups in the NEMURO model determine the consumption rate of the herring; herring consumption affects the zooplankton, and egestion and excretion contribute to the nitrogen dynamics. NEMURO was previously calibrated to field data for the West Coast Vancouver Island. Thirty-year simulations of herring growth and population dynamics were performed that used repeated environmental conditions for the lower trophic levels of NEMURO and historical environmental variables for the herring spawner–recruit relationship. Herring dynamics were calibrated to the west coast of Vancouver Island such that the coupled models reasonably duplicated observed herring weights-at-age and total herring biomass. Additional 30-year simulations under constant recruitment with herring coupled and uncoupled from NEMURO clearly showed the effects of the feedback mechanism between the two models and also showed that herring have small to moderate effects on their prey. Monte Carlo uncertainty analysis showed the importance of feeding- and respiration-related parameters to predicted individual and population herring growth. The utility of the NEMURO.FISH framework for improving our understanding of climate change effects on marine ecosystem dynamics is discussed.

The genetic structure of eulachon (Thaleichthys pacificus) populations was examined in an analysis of variation of 14 microsatellite loci representing approximately 1900 fish from 9 sites between the Columbia River and Cook Inlet, Alaska. Significant genetic differentiation occurred among the putative populations. The mean F(ST) for all loci was 0.0046, and there was a significant correlation between population genetic differentiation (F(ST)) and geographic distance. Simulated mixed-stock samples comprising populations from different regions suggested that variation at microsatellite loci provided reasonably accurate estimates of stock composition for potential fishery samples. Marine sampling indicated that immature eulachons from different rivers, during the 2 to 3 years of prespawning life in offshore marine waters, do not mix thoroughly. For eulachons captured incidentally in offshore trawl fisheries, there was a clear geographic cline in relative abundance of eulachons from different geographic areas. The sample from northern British Columbia was dominated by northern and central coastal populations of British Columbia, the sample from central British Columbia was composed of eulachons from all regions, and the sample from southern British Columbia was dominated by Columbia River and Fraser River populations. These results have implications for the management of trawl fisheries and conservation of spawning populations in some rivers where abundance is at historically low levels.

A 2-day REX Workshop on “Trends in herring populations and trophodynamics” was convened prior to the Ninth Annual Meeting in Hakodate, Japan (October 20-21, 2000). Papers were presented by 8 speakers from among 25-30 participants. At the workshop, we learned that there are long time series (80+ years) of data for herring populations related to catch, size-at-age, length and weight, spawning time, distribution and age composition. Shorter time series are available for biomass estimates, age-structured abundances, survival index, production and instantaneous growth rates. Process studies have examined food habits and energetics, vertical distribution, timing of migration, age-specific habitat requirements, larval survival and distribution, juvenile abundance and distribution, genetic structure of populations, densities of herring aggregations, gonad weight and fecundity and key competitors and predators.

Introduction [pdf, 0.17 MB] Warren S. Wooster [pdf, 0.12 MB] PICES - the first decade, and beyond Paul H. LeBlond [pdf, 0.03 MB] The Physical Oceanography and Climate Committee: The first decade D.E. Harrison and Neville Smith [pdf, 0.04 MB] Ocean observing systems and prediction - the next ten years Tsutomu Ikeda and Patricia A. Wheeler [pdf, 0.85 MB] Ocean impacts from the bottom of the food web to the top: Biological Oceanography Committee (BIO) retrospective Timothy R. Parsons [pdf, 0.2 MB] Future needs for biological oceanographic studies in the Pacific Ocean Douglas E. Hay, Richard J. Beamish, George W. Boehlert, Vladimir I. Radchenko, Qi-Sheng Tang, Tokio Wada, Daniel W. Ware and Chang-Ik Zhang [pdf, 0.2 MB] Ten years FIS in PICES: An introspective, retrospective, critical and constructive review of fishery science in PICES Richard F. Addison, John E. Stein and Alexander V. Tkalin [pdf, 0.12 MB] Marine Environmental Committee in review Robie W. Macdonald, Brian Morton, Richard F. Addison and Sophia C. Johannessen [pdf, 1.89 MB] Marine environmental contaminant issues in the North Pacific: What are the dangers and how do we identify them? R. Ian Perry, Anne B. Hollowed and Takashige Sugimoto [pdf, 0.36 MB] The PICES Climate Change and Carrying Capacity Program: Why, how, and what next? List of acronyms [pdf, 0.07 MB] (Document contains 108 pages)

In laboratory tests young Pacific herring (Clupea harengus pallasi) larvae were eaten by several species of hydromedusae common in coastal waters off British Columbia, including the previously controversial Sarsia tubulosa and by the scyphomedusa Aurelia aurita. Field collections and observations confirmed that the distributions of medusae and larvae overlap and that some medusae feed on herring larvae in nature. In coastal waters and bays of British Columbia, the hydromedusae Sarsia tubulosa or Aequorea victoria may be most abundant during the time of peak herring larvae abundance.Key words: herring, larvae, Clupea, Sarsia, Aequorea, predation, medusae