Identifying influential parameters of a multi-species fish size spectrum model for a northern temperate lake through sensitivity analyses

2021 ◽  
Vol 460 ◽  
pp. 109740
Author(s):  
David M. Benoit ◽  
Henrique C. Giacomini ◽  
Cindy Chu ◽  
Donald A. Jackson
Keyword(s):  
Sensitivity Analyses ◽  
Size Spectrum ◽  
Fish Size ◽  
Temperate Lake ◽  
Influential Parameters ◽  
Spectrum Model

scholarly journals Modeling the Dynamics of Multispecies Fisheries: A Case Study in the Coastal Water of North Yellow Sea, China

2020 ◽  
Vol 7 ◽  
Author(s):  
Jia Wo ◽  
Chongliang Zhang ◽  
Xindong Pan ◽  
Binduo Xu ◽  
Ying Xue ◽  
...  
Keyword(s):  
Model Validation ◽  
Fisheries Management ◽  
Yellow Sea ◽  
Sensitivity Analyses ◽  
Size Spectrum ◽  
Quality Of Data ◽  
Estimation Model ◽  
North Yellow Sea ◽  
Multispecies Fisheries ◽  
Spectrum Model

Ecosystem models have been developed for detecting community responses to fishing pressure and have been widely applied to predict the ecological effects of fisheries management. Key challenges of ecosystem modeling lie in the insufficient quantity and quality of data, which is unfortunately common in the marine ecosystems of many developing countries. In this study, we aim to model the dynamics of multispecies fisheries under data-limited circumstances, using a multispecies size-spectrum model (MSSM) implemented in the coastal ecosystem of North Yellow Sea, China. To make most of available data, we incorporated a range of data-limited methods for estimating the life-history parameters and conducted model validation according to empirical data. Additionally, sensitivity analyses were conducted to evaluate the impacts of input parameters on model predictions regarding the uncertainty of data and estimating methods. Our results showed that MSSM could provide reasonable predictions of community size spectra and appropriately reflect the community composition in the studied area, whereas the predictions of fisheries yields were biased for certain species. Errors in recruitment parameters were most influential on the prediction of species abundance, and errors in fishing efforts substantially affected community-level indicators. This study built a framework to integrate parameter estimation, model validation, and sensitivity analyses altogether, which could guide model development in similar mixed and data-limited fisheries and promote the use of size-spectrum model for ecosystem-based fisheries management.

scholarly journals Simulation of the Fate and Seasonal Variations ofα-Hexachlorocyclohexane in Lake Chaohu Using a Dynamic Fugacity Model

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Xiang-zhen Kong ◽  
Wei He ◽  
Ning Qin ◽  
Qi-Shuang He ◽  
Bin Yang ◽  
...  
Keyword(s):  
Seasonal Variations ◽  
Model Uncertainty ◽  
Suspended Solids ◽  
Diffusion Flux ◽  
Sensitivity Analyses ◽  
Lake Chaohu ◽  
Fugacity Model ◽  
Parameters Uncertainty ◽  
Influential Parameters ◽  
Good Agreement

Fate and seasonal variations ofα-hexachlorocyclohexane (α-HCH) were simulated using a dynamic fugacity model in Lake Chaohu, China. Sensitivity analyses were performed to identify influential parameters and Monte Carlo simulation was conducted to assess model uncertainty. The calculated and measured values of the model were in good agreement except for suspended solids, which might be due to disregarding the plankton in water. The major source ofα-HCH was an input from atmospheric advection, while the major environmental outputs were atmospheric advection and sediment degradation. The net annual input and output ofα-HCH were approximately 0.294 t and 0.412 t, respectively. Sediment was an important sink forα-HCH. Seasonal patterns in various media were successfully modeled and factors leading to this seasonality were discussed. Sensitivity analysis found that parameters of source and degradation were more important than the other parameters. The sediment was influenced more by various parameters than air and water were. Temperature variation had a greater impact on the dynamics of the model output than other dynamic parameters. Uncertainty analysis showed that the model uncertainty was relatively low but significantly increased in the second half of the simulation period due to the increase in the gas-water diffusion flux variability.

Shifts in plankton size spectra modulate growth and coexistence of anchovy and sardine in upwelling systems

2016 ◽  
Vol 73 (4) ◽  
pp. 611-621 ◽  
Author(s):  
T. Mariella Canales ◽  
Richard Law ◽  
Julia L. Blanchard
Keyword(s):  
Size Structure ◽  
Prey Availability ◽  
Empirical Work ◽  
Size Composition ◽  
Size Spectrum ◽  
Small Particles ◽  
Size Spectra ◽  
Factors Influencing ◽  
Spectrum Model ◽  
Model Scenarios

Fluctuations in the abundance of anchovy (Engraulis spp.) and sardine (Sardinops sagax) are widespread in marine ecosystems, but the causes still remain uncertain. Differences between the planktonic prey availability, selectivity, and predation between anchovy and sardine have been suggested as factors influencing their dynamics. Using a dynamical multispecies size-spectrum model, we explore the consequences of changes in plankton size composition, together with intraguild predation and cannibalism, on the coexistence of these species. The shift towards smaller plankton has led to a reduction in the growth rate of both species. The effect was more deleterious on anchovy growth because it is unable to filter small particles. In model scenarios that included the effects of cannibalism and predation, anchovy typically collapsed under conditions favouring smaller sized plankton. The two species coexisted under conditions of larger sized plankton, although strong predation in conjunction with weak cannibalism led to the loss of sardine. The model provides new testable predictions for the consequences of plankton size structure on anchovy and sardine fluctuations. Further empirical work is needed to test these predictions in the context of climate change.

scholarly journals Balanced harvesting is the bioeconomic equilibrium of a size-structured Beverton-Holt model

2016 ◽  
Vol 74 (1) ◽  
pp. 112-120 ◽  
Author(s):  
Michael J. Plank
Keyword(s):  
Single Species ◽  
Size Spectrum ◽  
Ecosystem Structure ◽  
Fishing Mortality ◽  
Biomass Transfer ◽  
Body Sizes ◽  
Relative Production ◽  
Ecosystem Structure And Functioning ◽  
Classical Size ◽  
Spectrum Model

Balanced harvesting (BH) was introduced as an alternative strategy to size-at-entry fishing with the aim of maintaining ecosystem structure and functioning. BH has been criticized on a number of grounds, including that it would require an infeasible level of micromanagement and enforcement. Recent results from a size-spectrum model show that the distribution of fishing mortality across body sizes that emerges from the behaviour of a large number of fishing agents corresponds to BH in a single species. Size-spectrum models differ from classical size-structured models used in fisheries as they are based on a bookkeeping of biomass transfer from prey to predator rather than a von Bertalanffy growth model. Here we investigate a classical Beverton-Holt model coupled with the Gordon-Schaefer harvesting model extended to allow for differential fishing pressure at different body sizes. This models an open-access fishery in which individual fishing agents act to maximize their own economic return. We show that the equilibrium of the harvesting model produces an aggregate fishing mortality that is closely matched to the production at different body sizes, in other words BH of a single species. These results have significant implications because they show that the robustness of BH does not depend on arguments about the relative production levels of small versus large fish.

A functional size-spectrum model of the global marine ecosystem that resolves zooplankton composition

2020 ◽  
Vol 435 ◽  
pp. 109265
Author(s):  
Ryan F. Heneghan ◽  
Jason D. Everett ◽  
Patrick Sykes ◽  
Sonia D. Batten ◽  
Martin Edwards ◽  
...  
Keyword(s):  
Marine Ecosystem ◽  
Size Spectrum ◽  
Spectrum Model ◽  
Functional Size

scholarly journals Parameter uncertainty of a dynamic multispecies size spectrum model

2016 ◽  
Vol 73 (4) ◽  
pp. 589-597 ◽  
Author(s):  
Michael A. Spence ◽  
Paul G. Blackwell ◽  
Julia L. Blanchard
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Size Structure ◽  
Management Strategies ◽  
Optimization Methods ◽  
Series Data ◽  
Size Spectrum ◽  
Aquatic Communities ◽  
The North ◽  
Spectrum Model

Dynamic size spectrum models have been recognized as an effective way of describing how size-based interactions can give rise to the size structure of aquatic communities. They are intermediate-complexity ecological models that are solutions to partial differential equations driven by the size-dependent processes of predation, growth, mortality, and reproduction in a community of interacting species and sizes. To be useful for quantitative fisheries management these models need to be developed further in a formal statistical framework. Previous work has used time-averaged data to “calibrate” the model using optimization methods with the disadvantage of losing detailed time-series information. Using a published multispecies size spectrum model parameterized for the North Sea comprising 12 interacting fish species and a background resource, we fit the model to time-series data using a Bayesian framework for the first time. We capture the 1967–2010 period using annual estimates of fishing mortality rates as input to the model and time series of fisheries landings data to fit the model to output. We estimate 38 key parameters representing the carrying capacity of each species and background resource, as well as initial inputs of the dynamical system and errors on the model output. We then forecast the model forward to evaluate how uncertainty propagates through to population- and community-level indicators under alternative management strategies.

scholarly journals Assessing uncertainty of a multispecies size-spectrum model resulting from process and observation errors

2015 ◽  
Vol 72 (8) ◽  
pp. 2223-2233 ◽  
Author(s):  
Chongliang Zhang ◽  
Yong Chen ◽  
Yiping Ren
Keyword(s):  
Life History ◽  
Community Structure ◽  
Fisheries Management ◽  
Dynamic Models ◽  
Environmental Variability ◽  
Size Spectrum ◽  
Sampling Errors ◽  
Fishing Activity ◽  
Scale Parameters ◽  
Spectrum Model

AbstractEcosystem models, specifically multispecies dynamic models, have been increasingly used to project impacts of fishing activity on the trophodynamics of ecosystems to support ecosystem-based fisheries management. Uncertainty is unavoidable in modelling processes and needs to be recognized and properly quantified before models are utilized. Uncertainty was assessed in this study for a multispecies size-spectrum model that quantifies community structure and ecological characteristics. The uncertainty was assumed to result from errors in fish life-history and metabolic scale parameters, environmental variability, fishing variability, and sampling errors. Given the same level of imprecision, metabolic scale parameters had the dominant influence on the uncertainty of the size spectrum modelling results, followed by life-history parameters. Both types of errors led to “scenario uncertainty”, suggesting the possible existence of alternative states of community structure. Environmental variability, fishing variability, and observation errors resulted in “statistical uncertainty”, implying that such uncertainty can be described adequately in statistical terms. The results derived from such a simulation study can provide guidance for identifying research priorities to help narrow the gap in scientific knowledge and reduce the uncertainty in fisheries management.

Implementing a multispecies size-spectrum model in a data-poor ecosystem

2016 ◽  
Vol 35 (4) ◽  
pp. 63-73 ◽  
Author(s):  
Chongliang Zhang ◽  
Yong Chen ◽  
Katherine Thompson ◽  
Yiping Ren
Keyword(s):  
Size Spectrum ◽  
Spectrum Model

scholarly journals Dome patterns in pelagic size spectra reveal strong trophic cascades

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Axel G. Rossberg ◽  
Ursula Gaedke ◽  
Pavel Kratina
Keyword(s):  
Trophic Cascades ◽  
Size Spectrum ◽  
Ecological Communities ◽  
Top Down ◽  
Community Size ◽  
Size Spectra ◽  
Local Maxima ◽  
Linear Pattern ◽  
Aquatic Food ◽  
Spectrum Model

Abstract In ecological communities, especially the pelagic zones of aquatic ecosystems, certain body-size ranges are often over-represented compared to others. Community size spectra, the distributions of community biomass over the logarithmic body-mass axis, tend to exhibit regularly spaced local maxima, called “domes”, separated by steep troughs. Contrasting established theory, we explain these dome patterns as manifestations of top-down trophic cascades along aquatic food chains. Compiling high quality size-spectrum data and comparing these with a size-spectrum model introduced in this study, we test this theory and develop a detailed picture of the mechanisms by which bottom-up and top-down effects interact to generate dome patterns. Results imply that strong top-down trophic cascades are common in freshwater communities, much more than hitherto demonstrated, and may arise in nutrient rich marine systems as well. Transferring insights from the general theory of non-linear pattern formation to domes patterns, we provide new interpretations of past lake-manipulation experiments.

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