Abundance Of Fish Stocks Research Articles

Own-price elasticity of open access supply as a long-run measure of fish stock abundance

Extensive criticisms of the management of marine fisheries periodically arise for a variety of reasons. While the complexity of the US fisheries management process is partially to blame, these reasons manifest themselves in statements that include a perceived decline in living marine resource abundance levels, a proposed change in the regulatory infrastructure, or improvements in stock abundance that some feel should allow for new entrants. Following these criticisms are calls to end the federal management process or at the very least the replacement of the fishery management agency leadership. These demands driven by rent seeking behavior use short-term declines in abundance as justification when the long-run abundance measures would have indicated improvements in stock abundance and achievement of management objectives. Empirical, long-run, stock abundance indices are estimated using synthetic demand methodology, based on bioeconomic fishery theory, applied in a general and partial equilibrium theory framework to determine if maximum sustainable yield (MSY) management targets have been achieved and maintained for four fisheries considered to be successfully managed and one characterized as a socio-economic disaster. The abundance of a fish stock is more influence by extra-market and extra-fishery forces than by fisheries managers who base allocation decisions solely on single species stock assessments.

Modelling the spatio-temporal distribution of age-1 Bay of Biscay anchovy (<i>Engraulis encrasicolus</i>) at spawning time

To efficiently manage and maintain fish stock abundance and age structure, it is necessary to understand variability in its spatial distribution. The main objective of this study was to describe the demographic structure of the Bay of Biscay anchovy during the main spawning period based on adult samples from 15 daily egg production method surveys. The proportion of age-1 individuals was modelled using generalized additive models with a binomial distribution and a logit link in relation to geographical and environmental covariates. The possibility of obtaining different models depending on the average age-1 proportion (low or high) was also explored. In general, age-1 individuals were found in shallow waters close to the coast, especially associated with the Gironde and Adour river plumes, whereas older individuals were prevalent on the shelf break and in oceanic waters. However, in years with a high age-1 proportion the younger individuals were also dominant in oceanic waters. These results could be used for management purposes, such as defining protected areas for particular age groups.

Killer whale (Orcinus orca) depredation effects on catch rates of six groundfish species: implications for commercial longline fisheries in Alaska

AbstractPeterson, M. J., Mueter, F., Hanselman, D., Lunsford, C., Matkin, C., and Fearnbach, H. 2013. Killer whale (Orcinus orca) depredation effects on catch rates of six groundfish species: implications for commercial longline fisheries in Alaska. – ICES Journal of Marine Science, 70: 1220–1232. Killer whale (Orcinus orca) depredation occurs when whales damage or remove fish caught on longline gear. This study uses National Marine Fisheries Service longline survey data from 1998–2011 to explore spatial and temporal trends in killer whale depredation and to quantify the effect of killer whale depredation on catches of six groundfish species within three management areas in Alaska: the Bering Sea, Aleutian Islands and Western Gulf of Alaska. When killer whales were present during survey gear retrieval, whales removed an estimated 54–72% of sablefish (Anoplopoma fimbria), 41–84% of arrowtooth flounder (Atheresthes stomias) and 73% (Bering Sea only) of Greenland turbot (Reinhardtius hippoglossoides). Effects on Pacific halibut (Hippoglossus stenolepis) and Pacific cod (Gadus macrocephalus) were significant in the Western Gulf only with 51% and 46% reductions, respectively. Overall catches (depredated and non-depredated sets) for all groundfish species significantly impacted by killer whale depredation were lower by 9–28% (p < 0.05). Effects on shortspine thornyhead (Sebastolobus alascanus) catches were not significant in any management area (p > 0.05). These results provide insight into the potential impacts of killer whale depredation on fish stock abundance indices and commercially important fisheries in Alaska and will inform future research on apex predator–fisheries interactions.

Harvested fish stocks in a changing environment

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 480:199-203 (2013) - DOI: https://doi.org/10.3354/meps10314 INTRODUCTIONImpact of climate and fisheries on sub-Arctic stocks Editors: J. M. Durant, N. C. Stenseth Marine Ecology Progress Series Vol. 480, pages 199–287 *Email: joel.durant@bio.uio.no ABSTRACT: Understanding the drivers (internal and external) that determine the productivity of marine ecosystems is challenging. For example, the correct estimate of recruitment is essential to estimate fish stock abundance. In this Theme Section, 5 papers explore the effect of fishing and climate on population structure across sub-Arctic ecosystems. The studies focus on how temperature- and fishing-induced changes in spatial and demographic population structure affect recruitment and population growth rate. The results suggest common patterns, but also highlight differences in the relative importance of fishing and climate among the populations and ecosystems examined. KEY WORDS: Climate · Non-stationarity · Spatial distribution · Recruitment · Population growth · Sub-Arctic Full text in pdf format PreviousNextCite this article as: Durant JM, Ottersen G, Stenseth NC (2013) Impact of climate and fisheries on sub-Arctic stocks. Mar Ecol Prog Ser 480:199-203. https://doi.org/10.3354/meps10314 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 480. Online publication date: April 22, 2013 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2013 Inter-Research.

Comparisons between abundance estimates from underwater visual census and catch-per-unit-effort in a patch reef system

ABSTRACT: Methods of underwater visual censuses (UVC) and catch-per-unit-effort (CPUE) areboth commonly used to estimate abundance of fish stocks. While each method is subject to certainbiases, in theory they should produce related measures of fish abundance for a specific site at agiven point in time, for species targeted by both methods. We tested relationships between esti-mates of abundance and biomass from UVC and experimental hook-and-line CPUE in a spatiallycomplex coral patch reef system. Fishes targeted by the CPUE method were significantly largerthan those sampled by UVC. Abundance estimates from UVC and CPUE were significantly corre-lated when the data were collected simultaneously—and over small spatial scales (<20 m). How-ever, this correlation was reduced when collection of UVC and CPUE data was separated by eithertime or space. Spatial autocorrelation in the fish community composition was not detected for mostspecies, and abundance estimates were highly variable over time and space. Our results show thatdifferences among monthly sampling periods were responsible for the greatest amount of variabil-ity in the data, and we recommend that abundance estimates should be derived from surveys car-ried out over multiple months to improve accuracy. While the UVC method is useful to detect awide variety of species, some species are more efficiently assessed using CPUE. Development ofcost-effective monitoring programs is crucial to document changes in reef fish populations andsupport the implementation of management regulations that may prevent further degradation ofreef fisheries worldwide.KEY WORDS: Commercial fish abundance · Coral reefs · Fisheries management · Samplingmethod · Spatial autocorrelation · SCUBA survey

Linking effort and fishing mortality in a mixed fisheries model: Comparing linear versus non-linear assumptions

Since the implementation of the Common Fisheries Policy of the European Union in 1983, the management of EU fisheries has been enormously challenging. The abundance of many fish stocks has declined because too much fishing capacity has been utilised on healthy fish stocks. Today, this decline in fish stocks has led to overcapacity in many fisheries, leading to incentives for overfishing. Recent research has shown that the allocation of effort among fleets can play an important role in mitigating overfishing when the targeting covers a range of species (multi-species—i.e., so-called mixed fisheries), while simultaneously optimising the overall economic performance of the fleets. The so-called FcubEcon model, in particular, has elucidated both the biologically and economically optimal method for allocating catches—and thus effort—between fishing fleets, while ensuring that the quotas are not exceeded. Until now, the FcubEcon modelling approach has assumed that there is a simplified linear relationship between effort and fishing mortality. The present study introduces an extension of the FcubEcon model, the so-called SOMER model, that allows this relationship to be non-linear by linking the biological catch equation with the economic production function. Furthermore, the SOMER model relaxes the assumption of the joint production of fishing metiers, unique and separately defined sub-fleets, to allow for more detail regarding the flexibility to target specific groups of species. Thereby, the SOMER model enables the managers to assess the alternative management scenarios more accurately than the existing models.

Characterizing variation in Northwest Atlantic fish-stock abundance

Abstract Rothschild, B. J., and Jiao, Y. 2012. Characterizing variation in Northwest Atlantic fish-stock abundance. – ICES Journal of Marine Science, 69: 913–922. Catch-per-tow indices obtained by research vessels for the years 1963–2009 from NAFO statistical areas 4W, 4X, 5Y, and 5Z were studied to determine how fish “apparent abundance” in the decade 2000–2009 differed from the long-term time-series. Cluster analysis of normalized catch-per-tow data indicated that the abundance and species composition of stocks in each statistical area changed dramatically over the 50-year period. There were decreases in thorny skate, ocean pout, cusk, witch flounder, and monkfish and increases in herring, haddock, northern shrimp, and spiny dogfish. Cluster analysis suggested that these decreases and increases were not gradual, but abrupt, and that these abrupt decreases and increases were concentrated in the decade of the 1980s. Observations of abrupt change were supported by regression-tree analysis of individual stocks. Examination of the interrelationship among abundance indices from different stocks by Bonferroni-adjusted correlation coefficients showed that the abundance trajectories of most stocks were uncorrelated. It appears that the set of population transitions during the decade of the 1980s was a dominant event in the statistical time-series.

Parental migration, climate and thermal exposure of larvae: spawning in southern regions gives Northeast Arctic cod a warm start

Temporal variability in environmental conditions met by early life stages is consid- ered a key driver of fluctuations in recruitment and abundance of fish stocks. Variability in spawn- ing grounds selected by the parental population can change the environmental conditions encountered by the offspring, with consequences for recruitment. We compared how changes in spawning ground distribution and interannual climatic variation influenced the temperature exposure of eggs and larvae of Northeast Arctic cod Gadus morhua along the Norwegian coast. By using a general circulation model and 20 yr of forcing data, we tracked eggs and larvae from various spawning grounds and mapped temperature exposure, potential growth rate and theoret- ical survival probabilities in space and time. We found that the temperature history integrated over the early larval stages decreased by almost 4°C from southern to northern spawning grounds. Thus, variations in spawning ground usage have the potential to outweigh the interannual envi- ronmental variability, and consequently, shifts in spawning grounds may be more important than climatic variability in determining recruitment success. The long-term northbound shift and trun- cation of spawning grounds of the Northeast Arctic cod is thought to be caused by a size-selective trawl fishery in the Barents Sea, which promotes smaller and early maturing individuals to spawn farther north. This selection could increase offspring vulnerability to climatic changes, thereby strengthening the link between climate and recruitment.

A comparative study of optimization methods and conventional methods for sampling design in fishery-independent surveys

Abstract Liu, Y., Chen, Y., and Cheng, J. 2009. A comparative study of optimization methods and conventional methods for sampling design in fishery-independent surveys. – ICES Journal of Marine Science, 66: 1873–1882. We have introduced and evaluated a procedure, the constrained spatial simulated annealing method, for developing an optimal sampling design for fishery-independent surveys. We used two criterion functions, minimization of the mean of the shortest distance (MMSD) and uniform distribution of point pairs for variogram estimation (WM), and three arrangements of the two criteria, all WM, all MMSD, and a combination of MMSD (2/3 of samples) and WM (1/3), to construct three optimized sampling designs (denoted as Designs I, II, and III, respectively). These three designs were compared in a simulation study with systematic sampling (Design IV) and stratified random sampling designs (Design V), commonly used in fishery-independent surveys. Three levels of sample size (small, medium, and large) were considered in the simulation study developed using a geostatistical approach. The results showed that for parameter estimation of the spatial covariance function, Design III was better than the other designs at relatively small sample size and Design II performed better than the other designs at relatively large sample size. For estimating fish stock abundance, the performance of the designs considered in this study can be ranked as follows: Design II &gt; Design IV &gt; Design III &gt; Design V &gt; Design I. It is clearly important to evaluate and improve sampling design based on historical survey data. Such a study allows us to identify an optimal sampling design to balance the quality of the data collected and the costs of the sampling programme, leading to the development and optimization of a sustainable and fishery-independent monitoring programme.

The variability of fisheries and fish populations prior to industrialized fishing: An appraisal of the historical evidence

This paper assesses the potentials of the available time series (50 years+) from historical records of the pre-industrial period until c. 1850–1950. A number of historical records from commercially important fish species are available for examining natural variability of fish stocks. Especially for North Atlantic and Japanese fisheries historical data have been retrieved from archives and museums, which cover time spans of 50–350 years. This makes it possible to examine natural variability of fish stocks over a much longer time span than what is normally possible with modern survey data and commercial catch data. Furthermore, historical evidence from the pre-industrialized period have the benefit of stemming from a period in time, when fishing had an insignificant impact on the abundance of open sea fish stocks. The best material comes from cod and herring fisheries, where it is possible to reconstruct CPUE as accurate as catch per boat per day absent, as well as changing spatial distribution over longer time periods.

Interdecadal variability of anchoveta abundance and overcapacity of the fishery in Peru

Paleontological and historical stock abundance estimates indicate that pelagic fish populations inhabiting upwelling ecosystems undergo large interdecadal variations in abundance with amplitudes equal to, if not larger than, the interannual variability. The interdecadal variability is characterized by periods of high and low abundance, termed “pseudo-cycles”, because of their irregular periodicity. Fisheries targeting small pelagic fish suffer from overall overcapitalization, like many other fisheries, but also from an additional overcapitalization problem: a phase displacement between rapid fish population decreases and a slower disinvestment which follows. This lag produces economic hardship. Here we document the fish:fishery relationship for the Peruvian anchoveta. Anchoveta pseudo-cycles of 20 to >100 years are observed, with the present stock abundance most likely located near upper part of the cycle. Fleet overcapacity expressed as the proportion of unused present capacity is estimated at 72% and processing overcapacity at 89%. A simple bio-economic model demonstrates the risks associated with the pseudo-periodicity in fish stock abundance in conjunction with fishery investment, open access, and overcapacity: a timing bomb for the fishing sector. The lag between disinvestment and decrease in fish abundance is quantified. A reduction of the fishing and processing capacity and measures to decrease the investment lag are recommended to limit the social, economical and political tensions that will result from the expected decrease in stock abundance. Finally, some management options to reduce these risks are discussed.

The freshwater habitats, fishes, and fisheries of the Orinoco River basin

The Orinoco River of Venezuela and Colombia is one of the great rivers of the world, ranking third by discharge after the Amazon and the Congo. In the Orinoco basin, riverine and floodplain habitats, including riparian forests, play key roles in the conservation of biodiversity and support commercial, sport, and subsistence fisheries. The basin's three major floodplains regulate the amplitude and duration of floods, maintain fertile agricultural terrain, provide habitat for numerous terrestrial and aquatic species, and support the fishery. The fish fauna, which includes some 1,000 species, encompasses a great deal of ecological diversity in terms of geographic distributions, habitat affinities, functional morphology, and reproductive and feeding strategies. The Orinoco fishery is still multispecific, with around 80 different species found in the fish markets at different times of year. Current estimates indicate that annual sustainable yield is 40,000 – 45,000 metric tons. Fish culture in the region is underdeveloped despite decades of research and promotion. There is no serious commercial trade for ornamental fishes. Large regions of the Orinoco basin are still in a relatively pristine state, but aquatic resources are increasingly threatened by habitat destruction, overharvesting, pollution, and hydrological perturbation. Scientific understanding of diversity hotspots, critical habitats, and conservation status of fishes in the basin is currently insufficient to satisfy management needs. Compliance to fishery regulations is low and fishing is drastically modifying the relative abundance, population structure, and distribution of fish stocks. However, many sectors of the Orinoco basin are unexploited or only lightly exploited, and fish stocks can recover quickly if given the opportunity. Stricter enforcement of current fishery regulations would reduce the likelihood of stock collapses and other, possibly irreversible, changes in the fishery.

An observing system for the collection of fishery and oceanographic data

Abstract. Fishery Observing System (FOS) was developed as a first and basic step towards fish stock abundance nowcasting/forecasting within the framework of the EU research program Mediterranean Forecasting System: Toward an Environmental Prediction (MFSTEP). The study of the relationship between abundance and environmental parameters also represents a crucial point towards forecasting. Eight fishing vessels were progressively equipped with FOS instrumentation to collect fishery and oceanographic data. The vessels belonged to different harbours of the Central and Northern Adriatic Sea. For this pilot application, anchovy (Engraulis encrasicolus, L.) was chosen as the target species. Geo-referenced catch data, associated with in-situ temperature and depth, were the FOS products but other parameters were associated with catch data as well. MFSTEP numerical circulation models provide many of these data. In particular, salinity was extracted from re-analysis data of numerical circulation models. Satellite-derived sea surface temperature (SST) and chlorophyll were also used as independent variables. Catch and effort data were used to estimate an abundance index (CPUE – Catch per Unit of Effort). Considering that catch records were gathered by different fishing vessels with different technical characteristics and operating on different fish densities, a standardized value of CPUE was calculated. A spatial and temporal average CPUE map was obtained together with a monthly mean time series in order to characterise the variability of anchovy abundance during the period of observation (October 2003–August 2005). In order to study the relationship between abundance and oceanographic parameters, Generalized Additive Models (GAM) were used. Preliminary results revealed a complex scenario: the southern sector of the domain is characterised by a stronger relationship than the central and northern sector where the interactions between the environment and the anchovy distribution are hidden by a higher percentage of variability within the system which is still unexplained. GAM analysis showed that increasing the number of explanatory variables also increased the portion of variance explained by the model. Data exchange and interdisciplinary efforts will therefore be crucial for the success of this research activity.

Growth accounting in a fishery

Since 1950, the real value of fish catches in Norway has about doubled, while the number of fishermen has declined by about 85 percent. This has made it possible to maintain fishermen's incomes roughly on par with other occupational groups in Norway. It is investigated to what extent this increase in labor productivity is due to accumulation of capital, increasingly abundant fish stocks, or technological progress. Since the capital stock in recent years is not much greater in real terms than in the early 1960s, it is tempting to ascribe most of the increase in labor productivity to technical progress. This, however, would leave out the role of fish stocks; if stocks have increased over this period, this would explain some of what otherwise appears as a technical progress. Using data on labor, capital, fish catches, and fish stock abundance 1961–2004 the development of total factor productivity is examined. Ignoring changes in fish stocks, total factor productivity is estimated to have increased by 0.8 percent per year. Accounting for changes in fish stocks raises this to 1.7–4.3 percent per year, depending on the importance assigned to stocks as factors of production.

Interlocked use of inland fish resources: a new management strategy under private property rights

Abstract Interlocked use of multiple inland vendace, Coregonus albula (L.), stocks is a relatively new strategy to exploit asynchronous fluctuations in abundance of natural fish stocks between waterbodies. It combines vendace stocks from different lakes or parts of lakes into one interlocked stock to be managed across waterbody ownership boundaries. Management of interlocked stocks can be regarded as one form of portfolio management. Exploitation of interlocked stocks should reduce the interannual variation in yield, and thus ensuring fishers more constant income and the market more constant material flow. The strategy requires fishers to increase their mobility, to benefit from asynchronous fluctuations in abundance of vendace stocks between exploitable waters. A postal inquire addressed to Finnish commercial inland fishers examined whether existing property rights institutions’ and fishers’ harvesting policies were appropriate to establish interlocked use of multiple vendace stocks. Almost half of fishers had, to some extent, reaped benefit from a fishing strategy that included small‐scale mobility, which is consistent with the proposed strategy. By harvesting three or four lakes and stocks, fishers increased their yield compared with exploiting one fishing ground and one vendace stock. Public ownership provided fishers access to stocks nearer their place of residence than other ownership types.

Rebuilding US fisheries: progress and problems

The Magnuson-Stevens Fishery Conservation and Management Act of 1996 requires an end to overfishing and the rebuilding of depleted fishery resources. Nine years later, the progress towards rebuilding overexploited marine fisheries in the United States is reviewed here. Despite the statutory mandate, overfishing and depletion of important fish stocks remains a widespread problem in the US. Sixty-seven fish stocks are currently under rebuilding plans mandated by law. Overfishing, where the fishing mortality rate exceeds the level that should support the maximum sustainable yield (FMSY), continues in 45% of the stocks managed in rebuilding plans. Seventy-two percent of these stocks are still considered overfished, with measurable abundance remaining depleted below a predetermined threshold according to the standards set by the National Marine Fisheries Service and the Regional Fishery Management Councils. Only three stocks have been rebuilt to levels that should produce maximum sustainable yield. However, fish stock abundance appears to be increasing in 48% of the stocks under rebuilding plans. The clearest cause of the lack of progress in rebuilding is the failure of many plans to reduce exploitation sufficiently to end overfishing.

Designing Marine Reserves for Fishery Management

Recent reports have raised serious concerns about the rapid declines of historically productive marine fishery resources and the degradation of essential fish habitats. This global crisis has spurred development of innovative management strategies to rebuild depleted fisheries and marine ecosystems. One highly touted strategy involves the design and creation of marine reserves (areas off limits to extractive uses) to rebuild fisheries and conserve marine biodiversity. In this paper, we propose an integrated sequence of methodologies that provides an objective, quantitative framework for the design of marine reserves in spatially heterogeneous coastal ocean environments. The marine reserve designs proposed here satisfy the multiple, often-conflicting criteria of disparate resource user groups. This research is the first attempt to explicitly explore the trade-off between the conservation goals of fishery management and coral reef protection and the consumptive interests of commercial and recreational fishing fleets. The spatial distribution and size abundance of reef fish stocks throughout the Florida Keys coral reef ecosystem were estimated from a database consisting of more than 18,000 visual samples taken from 1979 to 2002. These distributions of multispecies abundance and biomass, in conjunction with a geographic database of coral reef habitats, are used to demonstrate an integer goal programming methodology for the design of networks of marine reserves, called plans. Once multiple plans are proposed, a simulation model is used to assess the effects of reserve size and shape on select Florida Keys reef fish populations under dynamic spatial and temporal conditions.

The Bergen multifrequency analyzer (BMA): A new toolbox for acoustic categorization and species identification

Multifrequency split-beam echo sounders with nearly identical and overlapping acoustic beams have been regularly used in acoustic surveys for fish stock abundance estimation. Calibrated raw data from up to six simultaneously working echo sounders at 18, 38, 70, 120, 200, and 364 kHz were applied for developing a new processing tool for real-time acoustic target categorization and acoustic species identification. The system now handles raw data from the Simrad EK500 and EK60 split-beam echo sounders, and performs a stepwise, modular sequence of analysis, like bottom detection, noise quantification and removal, target categorization, and school detection in near-real time. Direct generation of new, synthetic echograms, based upon the measured frequency response of the targets, is also one of the most useful features of the system. This information may significantly increase the accuracy of acoustic survey estimates of fish and zooplankton. New routines for noise removal, target categorization, and school detection will be presented, as well as new methods for training and building the artificial experience of the analyzer.

Catchability and the spatial distribution of fishing vessels

A central problem when using commercial catch per unit effort (CPUE) as an index of fish stock abundance is that fishing vessels search for concentrations of fish. For a given stock abundance, CPUE may become high if the vessels succeed in finding patches of fish and low if the vessels distribute their catching operations more randomly. In this work, the relationship between catchability and two measures of the degree of spatial concentration of a trawl fleet (the fleet's spatial extent and the fleet's degree of spatial patchiness) is investigated for four different fish stocks. The catchability of northeast Arctic cod (Gadus morhua) is strongly related to the fleet's degree of spatial concentration, but the relationship is weaker for northeast Arctic haddock (Melanogrammus aeglefinus), and no relationships appear for two saithe (Pollachius virens) stocks. Our findings suggest that adjusting CPUE with a measure of the fleet's average degree of concentration relates CPUE more strongly with abundance for migratory stocks.

Growth and Abundance of Pacific Sand Lance, Ammodytes hexapterus, under differing Oceanographic Regimes

Dramatic changes in seabird and marine mammal stocks in the Gulf of Alaska have been linked to shifts in abundance and composition of forage fish stocks over the past 20 years. The relative value (e.g., size and condition of individual fish, abundance) of specific forage fish stocks to predators under temporally changing oceanographic regimes is also expected to vary. We inferred potential temporal responses in abundance, growth, and age structure of a key forage fish, sand lance, by studying across spatially different oceanographic regimes. Marked meso-scale differences in abundance, growth, and mortality existed in conjunction with these differing regimes. Growth rate within stocks (between years) was positively correlated with temperature. However, this relationship did not exist among stocks (locations) and differing growth rates were better correlated to marine productivity. Sand lance were least abundant and grew slowest at the warmest site (Chisik Island), an area of limited habitat and low food abundance. Abundance and growth of juvenile sand lance was highest at the coolest site (Barren Islands), an area of highly productive upwelled waters. Sand lance at two sites located oceanographically between the Barren Islands and Chisik Island (inner- and outer-Kachemak Bay) displayed correspondingly intermediate abundance and growth. Resident predators at these sites are presented with markedly different numbers and quality of this key prey species. Our results suggest that at the decadal scale, Gulf of Alaska forage fish such as sand lance are probably more profoundly affected by changes in abundance and quality of their planktonic food, than by temperature alone.