Bioeconomic Approach Research Articles

A bioeconomic approach to assess the impact of an alien invasive insect on timber supply and harvesting: a case study with Sirex noctilio in eastern Canada

This study presents a model that assesses the potential impact of a new alien insect species, Sirex noctilio Fabricius, on pine timber supply and harvest activities in eastern Canada. We integrate the spread of S. noctilio with a broad-scale growth and harvest allocation model. Projections of pine mortality range between 25 × 106 and 115 × 106 m3 over 20 years depending on S. noctilio spread and impact assumptions. Our model suggests Ontario could experience the highest, most immediate losses (78% of the potential losses across eastern Canada), with Quebec sustaining most of the rest of the losses over the next 20 years. Potential losses of $86 to $254 million per year are simulated after 20 years. The net present value of total harvest losses after 28 years of outbreak ranges between $0.7 to $2.1 billion. Adaptation policies decrease short-term losses by 46%–55% and delay larger harvest failures by 9–11 years. Without harvest adaptation, failures to maintain annual allowable cut levels may occur once the total area infested exceeds 15 × 106 ha. While better understanding and representing S. noctilio behaviour will involve a significant effort, there is a strong demand by policy makers for this kind of information.

Economic valuation of the vulnerability of world agriculture confronted with pollinator decline

There is mounting evidence of pollinator decline all over the world and consequences in many agricultural areas could be significant. We assessed these consequences by measuring 1) the contribution of insect pollination to the world agricultural output economic value, and 2) the vulnerability of world agriculture in the face of pollinator decline. We used a bioeconomic approach, which integrated the production dependence ratio on pollinators, for the 100 crops used directly for human food worldwide as listed by FAO. The total economic value of pollination worldwide amounted to €153 billion, which represented 9.5% of the value of the world agricultural production used for human food in 2005. In terms of welfare, the consumer surplus loss was estimated between €190 and €310 billion based upon average price elasticities of − 1.5 to − 0.8, respectively. Vegetables and fruits were the leading crop categories in value of insect pollination with about €50 billion each, followed by edible oil crops, stimulants, nuts and spices. The production value of a ton of the crop categories that do not depend on insect pollination averaged €151 while that of those that are pollinator-dependent averaged €761. The vulnerability ratio was calculated for each crop category at the regional and world scales as the ratio between the economic value of pollination and the current total crop value. This ratio varied considerably among crop categories and there was a positive correlation between the rate of vulnerability to pollinators decline of a crop category and its value per production unit. Looking at the capacity to nourish the world population after pollinator loss, the production of 3 crop categories – namely fruits, vegetables, and stimulants - will clearly be below the current consumption level at the world scale and even more so for certain regions like Europe. Yet, although our valuation clearly demonstrates the economic importance of insect pollinators, it cannot be considered as a scenario since it does not take into account the strategic responses of the markets.

Compensatory mitigation as a solution to fisheries bycatch–biodiversity conservation conflicts

Globally, fisheries catch of non-target species has major environmental impacts, resulting in social conflict, litigation, and fisheries closures. We use a bio-economic approach to demonstrate that compensatory mitigation – an innovative, market-influenced approach to fishery–conservation conflicts – can facilitate high-value uses of biological resources and cost-effective conservation gains for species of concern. We illustrate the strategy with a seabird example: levying fishers for their bycatch and using the funds to remove invasive mammals from breeding islands. Removal of invasive predators is 23 times more effective from a return-on-investment perspective (ie percent increase in population growth per dollar invested) in comparison to fisheries closures, and is more socio-politically feasible. A bycatch levy, which would increase with endangerment, provides an individual incentive for avoiding bycatch, the most effective mechanism for sustainable management of fisheries. Compensatory mitigation provides an opportunity to address a global concern, optimize conservation interventions, and forge an alliance between conservation and fisheries organizations.

Assessing the economic impact of invasive species: The case of yellow starthistle ( Centaurea solsitialis L.) in the rangelands of Idaho, USA

Yellow starthistle ( Centaurea solsitialis L.) is an invasive weed that creates problems for the management of Idaho's rangelands. A bioeconomic approach combined with an input–output economic model is used to estimate direct and secondary economic costs of the weed in relation to its interference with agricultural and non-agricultural benefits that rangelands provide. Direct economic costs of the infestations were estimated to be of 8.2 million ‘05 dollars per year, and secondary costs of 4.5 million ‘05 dollars per year, for a total of 12.7 million ‘05 dollars; agricultural related economic impacts accounted for 79% of this total cost, and non-agricultural for 21%.

Assessment of the Sustainability of Bushmeat Hunting Based on Dynamic Bioeconomic Models

Open-access hunting is a dynamic system in which individual hunters respond to changes in system variables such as costs of hunting and prices obtained for their catch. Sustainability indices used by conservationists ignore these human processes and focus only on the biological sustainability of current offtake levels. This focus implicitly assumes that offtake is constant, says little about the actual sustainability of the system, and fails to provide any basis for predicting the impact of most feasible management interventions. A bioeconomic approach overcomes these limitations by explicitly integrating both the biological and human components of the system. We present a graphical representation of a simple bioeconomic model of bushmeat hunting and use it to demonstrate the importance of considering system dynamics when assessing sustainability. Our results show that commonly used static sustainability indices are often misleading. The best method to assess hunting sustainability is situation dependent, but characterizing supply and demand curves, even crudely, has greater potential than current approaches to provide robust predictions in the medium term.

THE EFFECT OF SCENT-MARKING, FOREST CLEARING, AND SUPPLEMENTAL FEEDING ON MOOSE–TRAIN COLLISIONS

We analyzed how the application of scent-marking, forest clearing, and supplemental feeding correlated with the number of moose (Alces alces)–train collisions along the most vulnerable railroad stretch in Norway. Data on 1,045 collisions has been compiled for 18 years since 1985, and remedial actions have occurred during various periods since 1990. We used sections of the rail line where remedies had never been applied as control sections to estimate the expected number of collisions per year and per km. In this way, we took into account the yearly variation in the number of accidents by using the difference between the actual number of accidents and the expected number of accidents as our response variable. We compared the difference between periods when remedies were applied to periods without any remedy. We found a general 46% decrease in the number of accidents during years with a remedy compared to what would have been expected the same years without any remedy. Forest clearing and supplemental feeding seem to be reliable ways of reducing the number of collisions. Scent was only applied for short distances in a few years, and the beneficial effects we observed were questionable. We conclude that mitigative efforts may substantially reduce accidental mortality in moose populations if applied for long distances. We discuss the economics of game-vehicle collisions by performing a simple calculation to visualize the need for a bio-economic approach to the problem.

The consequences of different scenarios in the management of the gillnet and purse-seine fisheries targeting Pomatomus saltatrix and Cynoscion guatucupa in southern Brazil: a bio-economic approach

Abstract The bluefish Pomatomus saltatrix and the striped weakfish Cynoscion guatucupa are two of the most important commercially exploited species in southern Brazil. These species overlap spatially and temporally in southern Brazil and are exploited by a multi-purpose fleet. We analyse the consequences of different management options in terms of the bio-economy of the gillnet and purse-seine fisheries by considering P. saltatrix and C. guatucupa as the main targets. Development of the bio-economic model was based upon multi-fleet, single species models for P. saltatrix and C. guatucupa. The results are compared at the medium-term forecast level from stochastic simulations, and the technical interactions between the fleets that exploit the bluefish and striped weakfish are also addressed. The purse-seine fishery has a strong impact on the gillnet fishery. A management plan, which allocates moderate levels of effort for all co-existing fleets and interacting species, seems efficient, but effort should be controlled for P. saltatrix (for both fleets) and, for the gillnet fleet, relatively more trips should be allocated for C. guatucupa. For P. saltatrix, the best management relies upon the scenarios harvesting the oldest individuals.

A bio-economic application to the Cape Rock Lobster resource using a delay difference modelling approach

In many species, like the Cape Rock Lobster (Jasus lalandii), the life cycles of males and females differ. This may motivate the use of two-sex models in a stock-assessment analysis. It is also true for this resource, that juveniles do not reach sexual maturity immediately. Therefore a delay-difference model is appropriate. In this study we follow a bio-economic approach and use a two-sex delay-difference model to determine a maximum economic yield strategy. Thus we determine an economic optimum steady state solution at which to harvest this resource subject to the biological constraints of the species.

A bioeconomic approach to derive economic values for pasture-based sheep genetic improvement programs.

Economic values for a range of different maternal and carcass sheep performance traits were derived for hill sheep in the United Kingdom. A bioeconomic model that includes estimates of available energy supply and herbage intake for sheep from hill and mountain pastures, together with that from improved grassland, has provided a base from which to define the economic limitations to genetic improvement in harsh environments. The degree to which different farm systems can accommodate changes in animal performance as a result of genetic improvement was explored. Results showed that genetic improvement in harsh environments is likely to be of greater benefit to farms with fewer constraints to improvements in production, such as better quality pasture or a higher ratio of improved grassland to hill pasture. For farm types in the harshest locations, the economic value of improving litter size was only positive within defined production limits. Increasing litter size beyond these limits resulted in diminishing marginal returns because the costs of additional inputs outweighed the benefits of extra returns. Results also showed that relative improvements in maternal characteristics are at least as economically important as improvements in lamb carcass quality. The effects of variation in market prices on economic values for the major costs and returns of the sheep enterprises showed that, in general, economic values are robust. The methodology described could be adapted and applied to other extensive sheep systems worldwide.

Bioeconomic analysis of intensive production of the blue shrimp Litopenaeus stylirostris (Stimpson)

A bioeconomic approach was used to evaluate random variation of growth and mortality parameters and feed conversion ratio (FCR) for intensive production of the blue shrimp Litopenaeus stylirostris (Stimpson). Severe mortality problems caused by high impact diseases were not considered in this analysis. For a 50-ha farm, the maximum values of the internal rate of return (IRR=44%) and net revenue above operation costs (NR=US$1 211 000) were obtained for a stocking density of 67 postlarvae (PL) m−2 during winter–spring (cycle 1) and 65 PL m−2 during summer–autumn (cycle 2). Regardless of the density used for cycle 1, stocking at 50 and 65 PL m–2 for cycle 2 sufficed to obtain, respectively, IRRs greater than the minimum attractive IRRs of 15% and 30%. A frequency distribution of IRR, projected for densities of 67 and 65 PL m−2, showed high confidence in obtaining IRR values above 15% and 30% (i.e. confidence >99% and 92% respectively). The frequency distribution of NR showed that the farm could operate without economic losses. Stocking a minimum of 53% of the capacity of the farm would guarantee positive NR. Sensitivity analysis indicated that the IRR and NR were mainly influenced by mortality rate, selling price, density, final weight and FCR.

Long-term population structure, mortality and modeling of a tropical multi-fleet fishery: the red grouper Epinephelus morio of the Campeche Bank, Gulf of Mexico

This paper develops a precautionary bioeconomic approach for the red grouper ( Epinephelus morio) multi-fleet fishery in the Campeche Bank, Gulf of Mexico, based on a long-term analysis covering the years 1980–2000. Population structure was estimated through commercial sampling of the three fishing fleets participating in the fishery: two Mexican (one artisanal and the other industrial) and one Cuban (industrial). Length frequency distributions (LFDs) did not show significant differences between the Mexican industrial and the Cuban fleets, but differed from those of the artisanal fishery, which targets smaller individuals. The lack of differences in the LFDs between years suggests that the population structure was stable during the last two decades. However, the instantaneous coefficient of total mortality Z, estimated through length-converted catch curves, significantly increased during the 21-year period of analysis, being in average 1.22 times higher in 2000 than in 1980. Annual estimates of yield and Z, together with unit costs of effort and ex-vessel prices, were used as inputs to build a bioeconomic yield–mortality model. A sensitivity analysis was performed under three scenarios of natural mortality M (0.16, 0.25 and 0.35 per year). The yield at maximum economic yield ( Y MEY) and the associated mortality levels Z MEY and F MEY were always the most conservative bioeconomic reference points (BRPs). The yield at maximum biological production ( Y MBP), Y MEY and mortality-related BRPs were substantially lower than those based on maximum sustainable yield (MSY), thus constituting useful target BRPs for precautionary management. The bootstrap method used for determining the uncertainty associated at BRPs, shows that the best targets BRPs were Y MEY and Y MBP, whereas MSY is confirmed as a risky and limit BRP. A simple approach to the formulation of risk-averse management strategies was explored using the percentiles of cumulative distributions of MSY, Y MBP and Y MEY estimates generated from bootstrap against Z. We conclude that the red grouper fishery at Campeche Bank is overexploited and that immediate management actions are needed to prevent stock collapse.

Is the Current Regulation of the VIII Division European Anchovy Optimal

This paper sets out to assess the workability of the regulation currently in force in the European anchovy fishery of the VIII division. Particular attention is paid to the importance of the institutional regime in the allocation of natural resources. The study uses a bio-economic approach and takes into account the fact that, not only the European Union and the individual countries involved, but also some of the resource users or appropriators intervene in its management. In order to compare the effectiveness of the rules which, at the various levels, have been set up to restrict exploitation of the resource, the anchovy fishery is simulated in two extreme situations: open access and sole ownership. The results obtained by effective management will then be contrasted with those obtained from the maximum and zero profit objectives related with the two above-mentioned scenarios. Thus, if the real data come close to those derived from the sole ownership model it will have to be acknowledged that the rules at present in force are optimal. If, on the other hand, the situation more closely approach the results obtained from the open access model, we will endeavour in our conclusions to provide suggestions for economic policy measures that might improve the situation in the fishery.

Análisis bioeconómico de la pesquería de sardina (Sardinops sagax) y anchoveta (Engraulis ringens) de la zona norte de Chile

The industrial pelagic fishery of pacific sardine and anchovy from northern Chile was analysed through a bioeconomic approach including statistical data from the fishery (catch and effort between 1980 and 1991) and economic data (costs, revenues, investment and employment between 1988 and 1995) using a Gordon-Schaefer model. The economic data allowed us to conclude that costs from the fleet, fishmeal industry and canning industry decreased during the studied period. The financial investment occurred in two different periods. During the first period, investment increased between 1988 and 1991, and during the second period, between 1991 and 1995, investment decreased, which might be explained by a drop in fishmeal yield, catches and money exchange rate. The biological and economic reference points determined by the Gordon-Schaefer model showed that the fleet has harvested above both the effort in maximum economic yield (E MEY ) and effort in open access ( E OA ), while catches have exceeded the Maximum Sustainable Yield (MSY). These results are discussed in terms of the theoretical model's limitations to explain the functioning of the pelagic fishery fleet under backward-forward integration. It is hypothesized that more complex bioeconomic models would be subjected to identical limitation, because they would inadequately represent the integrated economic rationality of the industrial fishery. Some future worklines on the same topic are proposed.

A bio-economic approach to estimating economic values for UK hill sheep

Profitability of sheep production systems depends on several different animal characteristics rather than a single trait. Economic selection indexes combine information from more than one trait into an overall score, to maximise genetic gain. Economic values (EVs) are required for each trait in the breeding goal so that selection emphasis is proportional to the economic importance of each trait. Defining clear breeding goals is more complex for hill breeds than for other sectors of the sheep industry because they provide breeding females in addition to lambs for slaughter. The aims of this paper are to i) describe how EVs for breeding goal traits suitable for UK hill sheep were derived for a combination of carcass, maternal and ‘sustainability’ traits using a bio-economic model, and ii) show how these EVs vary between different production systems as a result of the differences in the physical constraints of farm size, pasture availability and the biological limits of sheep in extensive rearing environments.

Yield–mortality models: a precautionary bioeconomic approach

This paper develops a bioeconomic approach to yield–mortality models. The usefulness of the conceptual background of these models, and the application of the resulting reference points (RPs), are analysed in a precautionary management framework. Quantification of uncertainty by bootstrapping provided a more realistic comparison of the relative performance of RPs for management advice. Sensitivity analysis, performed under wide initial variations in the natural mortality coefficient M, displayed two important features of this bioeconomic model: (1) the yield at maximum economic yield ( Y MEY) and the associated mortality levels Z MEY and F MEY were always the most conservative RPs. This takes utmost importance at low M values, where maximum sustainable yield (MSY) and the yield at maximum biological production ( Y MBP) tended to coincide, whereas MEY and mortality-related RPs were substantially lower, thus constituting useful target RPs for precautionary management, (2) The RPs derived from the biological production curve were always lower than those derived from the sustainable yield curve. The former could be used as target RPs, whereas both MSY and F MSY should be considered as upper exploitation limits. Sensitivity analysis conducted with the economic input of the system, the unit cost of effort ( c), revealed consistency of the bioeconomic performance of the model with accepted theory, i.e., Y MEY approaches MSY with decreasing c values. A simple approach to the formulation of risk-averse management strategies was explored using decision theory. For this purpose, the maximax, maximin and minimax regret criterion were used to evaluate alternative management decisions under uncertainty, without the need for explicit statements of probabilities on alternative hypotheses. Results confirmed the need to consider economic and MBP related RPs for precautionary management. Guidelines for future work are suggested.

Co-viabilité des systèmes halieutiques

The limited nature of marine resources is becoming increasingly apparent nowadays. Moreover, the conventional models in population dynamics and bioeconomy have not proved operative in managing these resources, most of which are being chronically overexploited. In this paper co-viability is proposed as a conceptual model of fisheries designed to contribute to the definition of a practicable fisheries management. First, we present the crisis context in which the exploitation of marine resources and scientific research operate. The recent history of the Peruvian anchovy fisheries exemplifies the complex overlapping of political, bioecological and economic systems. We then introduce the results of several dynamic modelling exercises at different interfaces: i) environment — resource, where inertia seems to be the driving factor, and ii) resource — exploitation in which technical and biological diversity interact. An example relating to the pelagic market illustrates the problems of scale (global and local) linked to this issue. After this, we present and discuss the question of fisheries management with respect to the standard bio-economic approach, and the new alternatives. Fisheries systems are interactive sets of entities (ecosystems, exploitations, markets, institutions), each of which is characterised by a specific pace of evolution and specific functional scales. Complex interrelations are generated by interaction among their specific (biological and technical) diversities and by interdependence of their respective functional scales (global-local). Management of these systems proceeds on a sector-based approache linked to compartmentalised scientific knowledge. New conceptual settings have been proposed to address the management of fisheries from different perspectives. None emerges as more relevant than the other. Beyond its usefulness as a common concept, the coviability approach aims to work out which articulations would enable a mutual enrichment of different knowledge and perceptions. It could for instance contribute to reconciling the currently conflicting conservationist and productivistic standpoints in the field of marine resources.

Management strategies of stocking density and length of culture period for the Catarina scallop Argopecten circularis (Sowerby): a bioeconomic approach

Management strategies of stocking density and length of culture period for the Catarina scallop Argopecten circularis (Sowerby): a bioeconomic approach

Evaluation of management strategies — a bioeconomic approach applied to the Greenland Shrimp Fishery

A framework to evaluate the performance of alternative management strategies taking fleet behaviour and uncertainties in biological and economic data into account, is suggested. The evaluation framework incorporates an underlying system model generating the dynamics of the simulated structure, and a perceived system model which is an assessment-prediction model used to evaluate the state of the underlying system and to specify the fishery tactics. Biological and economic data from the shrimp (Pandalus borealis) fishery in the Davis Strait, is applied to the model. The study demonstrates that the long-term performance of the fishery tactics may deteriorate significantly if they are modified by implementation errors, exemplified by high-grading of catches, or by a political TAC setting process giving weight both to the biological advice and requests based on profit of prior years of fishing put forward by the fishery sector. In both cases the loss, expressed as a decrease in net present value of 10 years resource rent, may be greater than the loss due to incomplete knowledge of the underlying system structure.

Transboundary marine fisheries management. Recent developments and elements of analysis

A limit to the effectiveness of exclusive zones for fisheries management is the problem of transboundary impacts of harvesting. Recent development of this question and its analysis from an economic perspective are reviewed. Extending the scope of the bioeconomic approach implies increased uncertainty concerning the dynamics of the fisheries considered. Adherence to an optimal harvest plan depending on agreement on a “best” model of these dynamics, uncertainty may prevent co-operation where the model chosen influences the distribution of benefits derived from the resource. Elements of a case study are used to illustrate these issues, and the importance of management procedures for the regulation of these fisheries is underlined.

Management strategies of stocking density and length of culture period for the Catarina scallop Argopecten circularis (Sowerby): a bioeconomic approach

A bioeconomic analysis was made to help define management strategies of stocking density and length of culture period for the scallop Argopecten circularis (Sowerby). The internal rate of return (IRR) was used as a criterion for maximizing profit at different plant sizes. Analyses were made at low and high stocking rates. For plant sizes larger than 1.2 million juveniles, using high densities improved the IRR but had higher risk because of critical inconsistencies in survival. High sensitivity of the IRR to stocking density and culture period required these variables to be strictly controlled to maximize the IRR. The sensitivity of IRR to changes of ± 5% in the values of the parameters of the bioeconomic model was found to be significantly different (P < 0.01) between plant sizes. The IRR was particularly sensitive to the maximum size attainable by the organisms, mortality, sale price and cost of equipment for grow-out. The importance of considering uncertainty in the parameter estimates when projecting a pilot plant is addressed.