Harvest Control Research Articles

Harvest strategies for climate-resilient fisheries

Abstract A pressing challenge for climate-vulnerable fisheries is how to manage now for present and future climate change. In contrast to climate forecasting approaches, we track integrated signals of change for example populations in a climatically forced region and use stochastic dynamic programming to compare the performance of a range of management-ready policies over all possible future states. Our main results highlight: (i) that biomass-linked harvest control rules (HCRs) can partially compensate for changing production, even if the HCR is time invariant; and (ii) that the form of utility (e.g. risk neutral or risk averse) can result in remarkably different optimal decision paths. Performance over future horizons degrades marginally from dynamic HCRs to static HCRs (except at low productivity where differences are more pronounced) but markedly when the biomass level is ignored altogether, as is the case in many managed fish populations globally. Understanding the processes whereby climate affects productivity is important for interpreting past data, but forecasts are not needed for tactical decision making now. Instead, we argue that the priorities for managing fish stocks influenced by climate change are to: measure the current productivity, assess the current abundance of the stock, and respond with a dynamic HCR.

Stock-recruitment-environment relationships of invertebrate resources in Western Australia and their link to pro-active management harvest strategies

There are several ways to set biological reference points (BRP) for harvest strategies, but one of the most direct methods is to use the stock-recruitment relationship (SRR). Even if the SRR is not statistically significant, it provides valuable information about the spawning stock levels that don’t influence the recruitment that is relevant to setting BRP. Environmental factors, particularly extreme events such as the 2011 Western Australia (WA) marine heatwave, are typically a major driver of recruitment, so it is important to assess their influence as ignoring this effect may bias the SRR. This study examines the SRR for 13 invertebrate stocks in WA including lobster, prawn, scallop, abalone, pearl oysters and crabs. These stocks have long time series of fishery-independent juvenile abundance indices, which provide a clear signal of the year-class strength that improves the ability to assess the SRR and environmental effects. Eleven stocks showed a significant environmental effect on recruitment with seven stocks demonstrating a significant spawning stock effect. The stock-recruitment data is used to determine the BRP based on the species’ specific biological information, even when the relationship is not significant. Importantly, management action in the harvest control rules is not just reactive to low spawning stock levels but is proactive based on the juvenile abundance to ensure that the level of fishing results in future spawning stocks being maintained above the BRP. This evidence-based approach to setting BRPs and the proactive management approach adopted in the harvest strategy can be invaluable to fisheries management generally.

Fisheries management under incomplete information by optimal stochastic control and Hidden Markov Model filter

This paper deals with mathematical modelling of strategies in harvesting of fish populations. Since too aggressive harvesting may have severe consequences, a cautious control of the process is called for. The determination of optimal harvesting based on the biomass size is made even more challenging since there is considerable uncertainty in the estimation of the stock size, the so-called incomplete information problem.Fishery management is in this paper established as an optimal control problem for a model based on nonlinear stochastic differential equations, with economic performance as objective. The so-called certainty equivalence principle, by which the estimate is used for the purposes of optimal feedback control as if it were the certain value of the state variable, is adopted. Markov controls are identified by solving the stationary Hamilton-Jacobi-Bellman equation. State estimates are obtained by a Hidden Markov Model filter, where the forward Kolmogorov equation governs the temporal evolution of estimates with the uncertain quantities. Fishery profit over time as economic performance is computed by Monte Carlo simulations, in order to compare the performances of the strategies considering control rules and precautionary approach.Two control rules in harvest policy – harvest control rule and effort control rule – are compared, with respect to their robustness given the uncertainty. The effort control rule produces a significantly higher cumulated profits, and is less sensitive to the uncertainty in stock assessment present in the system. Moreover, a precautionary approach taking the uncertainty associated with biomass estimates into account, can be achieved via quantile estimators. This approach produces an economic gain by making a more appropriately cautious decision, and leads to sustainable harvesting of fish resources.

To be or not to be a target: that is the question to manage mixed fisheries

Abstract Simulation models are used extensively to evaluate the performance of fisheries management strategies, though they must be validated to ensure that they accurately represent the real system. One of the quantitative methods available to advance in the process of validating simulation models is global sensitivity analysis (GSA). However, its use in fisheries management has been very limited. When GSA is applied to management strategy evaluation implementations, it can also help manage available resources efficiently with respect to uncertainty in the management process and the conditioning of simulation models. Mixed-fisheries management plans were recently implemented for demersal fisheries in the Northeast Atlantic, which were evaluated previously using complex bioeconomic models. Here, we applied GSA to the model used in Iberian waters, employing an efficient model design to introduce uncertainty in every single input factor. While most biological factors contributed significantly to the variance of results, only few economic factors did. Moreover, we found that increasing accuracy in the stock assessment process would mainly impact management advice and that only the management of target stocks had a real impact on the system. This highlights the importance of properly managing hake (Merluccius merluccius), which is currently managed using an empirical harvest control rule.

Trade-offs and uncertainties in Northeast Pacific herring fisheries: ecosystem modelling and management strategy evaluation

AbstractPacific herring (Clupea pallasii) plays an important and multifaceted role in the Northeast Pacific as a forage fish in coastal ecosystems, target species for commercial fisheries, and culturally significant subsistence resource for coastal communities. This study comparatively evaluated herring fisheries management strategy performance relative to ecological and socioeconomic objectives. Management strategy evaluation employed a mass-balanced ecosystem operating model and accounted for parameter uncertainty, stock assessment error, and strategy implementation error through Monte Carlo resampling. Results revealed a notable trade-off between stable herring catches and high biomasses of herring and several predators. Herring biomass control point values influenced this trade-off more than harvest control rule form. All British Columbia and Alaska strategies yielded similar ecological and socioeconomic impacts relative to the unfished herring baseline. Precautionary strategies recommended for forage fish combined high ecosystem benefits and socioeconomic costs. Reducing fishing mortality fourfold within an existing strategy suggested a possible compromise solution to this trade-off. However, ecological impacts of all strategies were sensitive to operating model parameter uncertainty, stock assessment error, and strategy implementation error, with the potential for undesirable ecosystem states across all strategies. This study suggests trade-offs among management objectives should be considered in pursuing ecosystem-based fisheries management for forage fish.

Should harvest control rules for male-only fisheries include reproductive buffers? A Bering Sea Tanner crab (Chionoecetes bairdi) case study

Highly variable recruitment and a complex harvest strategy resulted in dramatic inter-annual changes in historical catches, including prolonged closure periods, for Bering Sea Tanner crab (Chionoecetes bairdi). Current management regulations, linked to recent frequent closures, led to an industry-initiated cooperative effort to reevaluate the harvest control rule (HCR) that forms part of the State of Alaska harvest strategy. Management strategy evaluation (MSE) was used to assess conservation and economic trade-offs of fifteen HCR options that differed in how females were considered. Several male-only HCRs performed similarly to those that accounted for females. However, the inclusion of both sexes reflected conservation and economic objectives while acknowledging the uncertainty around reproductive dynamics. The HCR selected by the Alaska Board of Fisheries included a threshold for opening the fishery based on mature male biomass (MMB), scalars based on relative levels of mature female biomass (MFB) and MMB that determine the exploitation rate on MMB, and a maximum exploitation cap on industry-preferred sizes of legal males. This work illustrates how manager-stakeholder collaboration may enable improved fishery management. Our analysis provided managers with a tool to facilitate productive and transparent dialogue with industry, with the goal of accounting for conservation and economic objectives, given some of the underlying biological uncertainty associated with reproductive dynamics. This study demonstrates that the inclusion of reproductive buffers in HCRs for male-only fisheries may be able to better achieve conservation goals without sacrificing economic performance.

Data Poor Approach for the Assessment of the Main Target Species of Rapido Trawl Fishery in Adriatic Sea

Information on stock status is available only for a few of the species forming the catch assemblage of rapido fishery of the North-central Adriatic Sea (Mediterranean Sea). Species that are caught almost exclusively by this gear, either as target (such as Pectinidae) or accessory catches (such as flatfishes apart from the common sole), remain unassessed mainly due to the lack of data and biological information. Based on cluster analysis, the catch assemblage of this fishery was identified and assessed using CMSY model. The results of this data-poor methodology showed that, among the species analyzed, no one is sustainably exploited. The single-species CMSY results were used as input to an extension of the same model, to test the effect of four different harvest control rule (HCR) scenarios on the entire catch assemblage, through 15-years forecasts. The analysis showed that the percentage of the stocks that will reach Bmsy at the end of the projections will depend on the HCR applied. Forecasts showed that a reduction of 20% of fishing effort may permit to most of the target and accessory species of the rapido trawl fishery in the Adriatic Sea to recover to Bmsy levels within 15 years, also providing a slight increase in the expected catches.

Management Strategy Evaluation: Allowing the Light on the Hill to Illuminate More Than One Species

Management strategy evaluation (MSE) is a simulation approach that serves as a “light on the hill” (Smith, 1994) to test options for marine management, monitoring, and assessment against simulated ecosystem and fishery dynamics, including uncertainty in ecological and fishery processes and observations. MSE has become a key method to evaluate trade-offs between management objectives and to communicate with decision makers. Here we describe how and why MSE is continuing to grow from a single species approach to one relevant to multi-species and ecosystem-based management. In particular, different ecosystem modeling approaches can fit within the MSE process to meet particular natural resource management needs. We present four case studies that illustrate how MSE is expanding to include ecosystem considerations and ecosystem models as ‘operating models’ (i.e., virtual test worlds), to simulate monitoring, assessment, and harvest control rules, and to evaluate tradeoffs via performance metrics. We highlight United States case studies related to fisheries regulations and climate, which support NOAA’s policy goals related to the Ecosystem Based Fishery Roadmap and Climate Science Strategy but vary in the complexity of population, ecosystem, and assessment representation. We emphasize methods, tool development, and lessons learned that are relevant beyond the United States, and the additional benefits relative to single-species MSE approaches.

Indirect Impacts of COVID-19 on a Tropical Lobster Fishery’s Harvest Strategy and Supply Chain

The Torres Strait tropical rock lobster Panulirus ornatus (TRL) fishery is of immense social, cultural and economic importance to the region’s Indigenous fishers from both Australia and Papua New Guinea (PNG). During 2020, the COVID-19 pandemic indirectly impacted this fishery as well as a number of other fisheries reliant on international export markets. The TRL fishery is managed using an empirical (data-based) Harvest Control Rule (eHCR) to rapidly provide a recommended biological catch (RBC), based on catch, fishery-independent survey indices and catch-per-unit-effort (CPUE). Here, we summarize the impacts of COVID-19 on each of these critical data inputs and discuss whether the eHCR was considered adequately resilient to this unprecedented disruption to the system. Next, we use a quantitative supply chain index to analyze the impact of disruptions to the supply chain, and inform on potential adaptation strategies. The catch and CPUE data were impacted to varying degrees by external constraints influencing fishing effort, but the fishery-independent survey wasn’t affected and hence there remains an unbroken survey time-series for the fishery extending back to 1989. The eHCR was shown to be reasonably robust because it incorporates longer-term trends over a 5-year period, and accords substantially more weighting (80%) to the fishery-independent survey rather than CPUE data which can be affected by trade and other disruptions. Despite the eHCR not having been tested for scenarios such as a global pandemic, this robustness is a positive given the types of disruptions we will likely face in future climate. The weak links identified in the supply chain were the same as those previously highlighted as sensitive to climate change disruptions. Our supply chain analysis quantifies the impact on system resilience of alternative paths connecting producers to consumers and reinforces that supply chains may be particularly vulnerable to external disruptions if they are not sufficiently diverse.

Numerical Simulations and Control of Offshore Energy Harvesting Using Piezoelectric Materials in a Portal Frame Structure

Buoy systems are an alternative for micropowering small devices in remote locations. Portal frames are very useful to harvest the energy of the waves into usable energy. Thus, using the current models for a portal frame in the literature and the spectrum of available energy in sea waves, a nonlinear mathematical model accounting for the coupling of a nonlinear piezoelectric material is considered. The neighbour of selected variables is analyzed and then optimized by a process utilizing the particle swarm optimization (PSO) algorithm. Furthermore, an optimal control using the linear-quadratic regulator (LQR) controller is applied to control the load resistance of the piezoelectric circuit. The optimization process and the LQR show to be effective. The results show a general gain due to optimization and a relatively small gain using the controller.

Wireless Power and Energy Harvesting Control in IoD by Deep Reinforcement Learning

Internet of Drones (IoD), which deploys several drones in the air to collect ground information and send them to the IoD gateway for further processing, can be applied in traffic surveillance and disaster rescue. The performance of IoD is greatly affected by drones' battery capacities. We hence utilize the energy harvesting technology to charge the batteries and the wireless power control to adjust the drone wireless transmission power in order to address this challenge. In our work, we investigate the joint optimization of power control and energy harvesting control to determine each drone's transmission power and the transmitted energy from the charging station in time-varying IoD networks. Our objective is to minimize the long-term average system energy cost constrained by the drones' battery capacities and quality of service (QoS) requirements. A Markov Decision Process (MDP) is formulated to characterize the power and energy harvesting control process in time-varying IoD networks. A modified actor-critic reinforcement learning algorithm is then proposed to tackle our problem and its performance is demonstrated via extensive simulations.

Adapting Simple Index-Based Catch Rules for Data-Limited Stocks to Short-Lived Fish Stocks’ Characteristics

Most of the methods developed for managing data-limited stocks have been designed for long-lived species and result in a poor performance when applied to short-lived fish due to their high interannual variability of stock size (IAV). We evaluate the performance of several catch rules in managing two typical short-lived fish (anchovy-like: characterized by high natural mortality, and hence, IAV, and full maturity at age 1; and sprat/sardine-like: with medium natural mortality and IAV, being fully mature at age 2). We followed the management strategy evaluation approach implemented in FLBEIA software to test several model-free harvest control rules, where the Total Allowable Catch (TAC) is yearly modified according to the recent trends in an abundance index (n-over-m rules: means of the most recent n values over the precedent m ones). The performance of these rules was assessed across a range of settings, such as time-lags between the index availability and management implementation, and alternative restrictions on TACs’ interannual variability (the uncertainty caps, UC). Moreover, we evaluated the sensitivity of the rule performance to the operating model assumptions (stock type, productivity, recruitment variability and initial depletion level) and to the observation error of the index. In general, the shorter the lag between observations, advice and management, the bigger the catches and the smaller the biological risks. For in-year management, 1-over-m rules are reactive enough to stock fluctuations as to gradually reduce risks. The 1-over-2 rule with symmetric 80% UCs reduces catches and risks toward precautionary levels in about 10 years, faster than if applied unconstrained (i.e., without UC), whilst the ICES default 2-over-3 rule with symmetric 20% UC is not precautionary. We prove that unconstrained rules gradually reduce the fishing opportunities, with amplified effects with increasing IAV. This property explains the stronger reductions of catches and risks achieved for the anchovy compared to the sprat/sardine-like stocks for any rule and the balance between catches and risks as the index CV increases. However, to avoid unnecessary long-term losses of catches from such reduction properties, it is suggested that the rules should be applied provisionally until a better assessment and management system is set up.

Pengelolaan Sumber Daya Ikan Cakalang didaratkan di Pelabuhan Perikanan Nusantara (PPN) Prigi, Trenggalek: Aplikasi Feedback Harvest Control Rule

Cakalang (Katsuwonus pelamis) is one of the leading export commodities landed at the Prigi Fishing Port (PPN Prigi). Skipjack tuna fisheries management conducted the conventional single-species Schaefer model which is often applied although it is not technically suitable for multispecies fishery. The application of feedback harvest control rule (HCR) is an alternative harvest strategy that has been successfully implemented and validated for multispecies fishery. This study estimated allowable biological catch by applying two harvest strategies, HCR feedback and Schaefer surplus production model using catch-effort data of skipjack tuna landed at PPN Prigi in the period 2010 - 2019. Model Schaefer pointed out that catches have exceeded the maximum sustainable yield () even employed low the fishing effort which was under the fishing mortality consistent with achieving MSY (). The application of feedback HCR that has been previously validated can be an alternative of harvest strategy for use in fisheries where only mixed species data is available. 
 Key words: multispecies fishery, harvest strategy, Schaefer model, maximum sustainable yield, single-species approach

The implementation gap in Canadian fishery policy: Fisheries rebuilding and sustainability at risk

Fisheries and Oceans Canada (DFO) established the Sustainable Fisheries Framework (SFF) in 2009 to help meet Canada’s international commitments towards sustainable fisheries management. The SFF is a suite of policies and tools intended to ensure the precautionary approach (PA) is incorporated into fisheries management. Seven years later (2016) a federal government audit by the Canadian Commissioner of the Environment and Sustainable Development (CESD) found that although DFO had identified key components necessary for successful fisheries management in the SFF, it had failed to put these components in place for many stocks and did not always apply them even when they were in place. The DFO response to the CESD audit included a commitment to develop work plans with deliverables outlining priorities and timelines for implementing key aspects of the SFF: reference points, harvest control rules, management plans and rebuilding plans for critically depleted stocks. The present study evaluated progress towards meeting this commitment and found that only 38% of the expected products were completed, 14% are in progress, 40% have progress delayed and are not proceeding as anticipated, while the remaining 8% were suspended. This weak performance highlights a larger trend of inadequate and slow implementation of legislative and policy tools in the management of Canada’s fisheries and oceans. With declining health status of Canadian stocks and less than half of critical stocks with rebuilding plans, these failures are having a significant impact on the ability of good policy to promote the long-term health of Canada’s fisheries and fishing communities.

Enhancing rainfed wheat productivity through technology validation and dissemination in Nertiti locality of Central Darfur State-Sudan

This research has been conducted in Nertiti locality of central Darfur State during 2020/2021 cropping season in order to enhance rainy wheat productivity through technology validation and dissemination. Farmers Field School was established with 25 farmers (5 men and 20 women). On-station demonstration farm was conducted with an area of 2feddan. Improved wheat variety Zakia (1feddan) grown versus Nillin (0.5 feddan) and local (0.5 feddan) to evaluate crop performance and potentiality. Clustered random sampling technique applied. Evaluation questionnaires developed randomly to 20 farmers to know farmers perceptions on wheat performance and productivity. Farmers subjected to farming training in wheat technologies of land preparation, sowing date, seed preparation, seed dressing, weeding, water harvesting, soil conservation, pests and diseases control, seed production technologies and harvest and post harvest technologies. Results showed that excessive rainfall variation during reproductive growth affect wheat yield by 32%. Socioeconomic characteristics and frequency distribution of farmers revealed that 80% of FFS participants were educated and 20% illiterate. 10% of farmers have farm size less than 1 feddan, 50% have 1-2 feddan, 30% have farm size range between 3-4 feddan and 10% have more than 4 feddan. Agriculture is the main source of income (80%), while 20% traders and pity trading. Results noted that 90% of FFS participants have no extension services and only 10% have.40% of respondent’s have experience in wheat production, while 60 have no experience.40% of participants perceived that improved wheat is resistant to water logging and high rain fall, 20% resist to insects, 30% high yielded and 10% said low yielded. Crop productivity trend showed that highest grain yield was obtained by improved Zakaia (655 kg/feddan) followed by Nillin (626 kg/feddan), while the lowest yield gained by local (424 kg/fedan). It was also recorded that improved Zakia exceed local and Nillin yields by 54% and 5%, respectively. Partial crop budget result revealed that all treatments were financially gave positive net returns. Improved Zakia gave highest net returns (SDG 21,500), Nillin (SDG18, 900) and the lowest net returns obtained by local wheat (SDG 15,000). Study recommended training in wheat technologies and enhancing the role of research station in the study area.

Insights into the regulation mechanism of ring-shaped magnetoelectric energy harvesters via mechanical and magnetic conditions* *Project supported by the National Natural Science Foundation of China (Grant No. 11702202), the Fundamental Research Funds for the Central Universities, China (Grant No. JB210410), and the the National Natural Science Foundation of China (Grant No. 51805401).

This paper presents a theoretical model for predicting and tuning magnetoelectric (ME) effect of ring-shaped composites, in which stress boundary conditions are empoyed and the multi-field coupling property of giant magnetostrictive materials are taken into account. A linear analytical solutions for the closed- and open-circuit ME voltages are derived simultaneously using mechanical differential equations, interface and boundary conditions, and electrical equations. For nonlinear ME coupling effect, the nonlinear multi-field coupling constitutive equation is reduced to an equivalent form by expanding the strains as a Taylor series in the vicinity of bias magnetic field. Sequentially, the linear model is generalized to a nonlinear one involving the field-dependent material parameters. The results show that setting a stress-free condition is beneficial for reducing resonance frequency while applying clamped conditions on the inner and outer boundaries may improve the maximum output power density. In addition, performing stress conditions on one of the boundaries may enhance ME coupling significantly, without changing the corresponding resonance frequency and optimal resistance. When external stimuli like bias magnetic field and pre-stress are applied to the ring-shaped composites, a novel dual peak phenomenon in the ME voltage curve around resonance frequencies is revealed theoretically, indicating that strong ME coupling may be achieved within a wider bias field region. Eventually, the mutual coordination of the bias field and pre-stress may enhance ME coupling as well as tuning the resonance frequency, and thus is pivotal for tunable control of ME energy harvesters. The proposed model can be applied to design high-performance energy harvesters by manipulating the mechanical conditions and external stimuli.

Seeds germination of Guizotia abyssinica (L.f.) Cass. stored in different environments and packages

Seed quality is defined by several factors such as genetic, physical, physiological and sanitary attributes. Even with all good factors involved, germinating power loss occurs. However, this loss may be reduced by performing procedures to maintain quality, as storage local and packaging. Thus, the objective of the work was to identify the best environment and packaging for storing niger seeds by analyzing germination and seedling biometry. Samples were separated according to treatments being three types of packaging: paper bag (permeable), plastic bag (semi-permeable) and glass container (impermeable). All packages were storage in two environment: storage shad and cold chamber. For all evaluations sub-samples were removed of each type of pack and environment being at one day after harvest (control), 30, 60, 90, 120 and 150 days of storage. The work was conducted at Laboratory of Seed Technology of Grand Dourados Federal University (UFGD). The experimental design was completely randomized, in a factorial scheme 6 × 6 (treatments x days of storage), with four replicates of 50 seeds each. Sowing was performed between "germitest" papers and rolls were kept in a germinator at a temperature of 25°C under constant white light, for 10 days. The traits evaluated were: first count of germination, percentage of germination and seedling length. Storage locations and type of packaging interfered significantly to development of niger (Guizotia abyssinica (L.f.) Cass.) seed germination. The best results in germination were found in seeds stored in glass container in storage shed and in plastic bag in cold chamber.

Minimum size limits and the reproductive value of numerous, young, mature female fish.

Fisheries management relies on various catch and effort controls to preserve spawning stock biomass and maximize sustainable yields while limiting fishery impacts on marine ecosystems. These include species-specific minimum or maximum size limits to protect either small non-reproductive subadults, a portion of reproductively mature adults, or large highly fecund individuals. Protecting size classes of mature fish is expected to yield a viable source of larvae for replenishing populations and reduce the risk of recruitment overfishing, yet size-specific recruitment contributions have rarely been assessed empirically. Here, we apply genetic parentage analysis to measure the reproductive success of a size-structured population of a commercially important species of coral grouper (Plectropomus maculatus-Serranidae) in no-take marine reserves (NTMRs) in the Great Barrier Reef Marine Park, Australia. Although the per capita reproductive success of individual fish increases rapidly with body length, the numerous young mature female fish, below the minimum size limit (MSL) (38 cm total length), were responsible for generating disproportionately large contributions (36%) towards larval replenishment of both fished and reserve reefs. Our findings indicate that MSLs are an effective harvest control measure to safeguard a portion of the spawning stock biomass for coral grouper and supplement recruitment subsidies assured from NTMRs.

Fodder cum grain dual harvests from rice (Oryza sativa) for enhanced productivity in Andaman's

An experiment was conducted during kharif 2016-17 to assess the impact of fodder harvest on grain production and system productivity of long duration photosensitive rice C-14-8. For this, five fodder harvest treatments, FHTs {no fodder harvest (FH) control, FH at 30, 45, 60 and 75 days after transplanting (DAT) of rice} were evaluated in Randomised Complete Block Design with four replications. The results revealed that 75 DAT FHT has produced significantly higher dry fodder and crude protein yields (6.30 and 0.538 t/ha), whereas 30 and 45 DAT FHTs has higher grain yields. However, the system productivity measured as rice equivalent yield and net income indicated that FH at 75 DAT was promising (4.23 t/ha and ` 19088/ha). Lodging in grain alone producing crop (95%) was reduced to 24% by taking FH at 75 DAT. Thus, the study establishes fodder cum grain production system of rice as a potential solution to augment fodder shortages while enhancing the grain production from ratoon owing to reduced lodging.

The impact of alternative age-length sampling schemes on the performance of stock assessment methods

Stock assessments based on fitting age-structured population dynamics models using the integrated approach usually require data on the length-/age-structure of fishery removals and age-length data to estimate key population parameters such as growth rates, recruitment, natural mortality rates and selectivity. The errors in the estimates of these population parameters directly impact the ability to estimate biomass and hence recommended catch limits based on harvest control rules. The performance of a stock assessment method therefore depends in part on the quality of these “composition” data. Simulation is used to evaluate the effect of a range of effective sample sizes for the length-composition and conditional age-at-length data on the errors in estimating spawning biomass, depletion, recruitment, selected population model parameters, and key model outputs, including catch limit recommendations. Multiple operating models, including those that result in the estimation method being mis-specified, are considered, and the simulations account for the effects of life history, catch history and current stock status. As expected, the errors in estimates of management-related quantities are less for greater effective sample sizes, but effective sample size is seldom the major determinant of the magnitude of estimation errors. The effect of sample size on relative errors is neither linear nor exponential, and spatially-unbalanced sampling is more detrimental than infrequent collection of composition data but with larger sample sizes. The quantitative results are likely case-specific, as they depend on several aspects of the operating model; the framework of this paper can be applied to specific fisheries, in combination with an algorithm that links effective to actual sample sizes.