Sturla Furunes Kvamsdal

An Overview of Empirical Analysis of Behavior of Fishermen Facing New Regulations

The biological resources of the sea have long fascinated man. The mystery of what lies beneath the surface has stimulated his imagination and nurtured hope that in this vast area there are resources capable of feeding a growing and a still hungry population for centuries to come. But, at the same time, realization of this hope is impeded by the opacity, instability, and sheer magnitude of the medium itself - by mans inability to see and hold. Fishing - one of mans earliest callings - is still haphazard and subject to the vagaries of weather, ocean currents, and mysterious migrations (Christy and Scott, 1965, p. v).

Optimal maintenance scheduling of local public purpose buildings

We formulate the maintenance scheduling decision as a dynamic optimization problem, subject to an accelerating decay. This approach offers a formal, yet intuitive, weighting of the trade-offs involved when deciding a maintenance schedule. The optimal maintenance schedule reflects the trade-off between the interest rate and the rate at which the decay accelerates. The prior reflects the alternative cost, since the money spent on maintenance could be saved and earn interests, while the latter reflects the cost of postponing maintenance. Importantly, it turns out that it is sub-optimal to have a cyclical maintenance schedule where the building is allowed to decay and then be intensively maintained before decaying again. Rather, local governments should focus the maintenance either early in the building’s life span and eventually let it decay towards replacement/abandonment or first let it decay to a target level and then keep it there until replacement/abandonment. Which of the two is optimal depends on the trade-off between the alternative cost and the cost of postponing maintenance.

Technical Change as a Stochastic Trend in a Fisheries Model

ABSTRACT Technical change is generally seen as a major source of growth, but usually cannot be observed directly and measurement can be difficult. With only aggregate data, measurement puts further demands on the empirical strategy. Structural time series models and the state-space form are well suited for unobserved phenomena, such as technical change. In fisheries, technical advance often contributes to increased fishing pressure, and improved productivity measures are important for managers concerned with efficiency or conservation. I apply a structural time series model with a stochastic trend to measure technical change in a Cobb-Douglas production function, considering both single equation and multivariate models. Results from the Norwegian Lofoten cod fishery show that the approach has both methodological and empirical advantages when compared with results from the general index approach, which has been applied in the literature. JEL Codes: C22, O39, Q22.

The Ensemble Kalman Filter in Bioeconomics

We demonstrate the power of the Ensemble Kalman Filter in specifying ecosystem models ideal for bioeconomic analysis. Bioeconomic analysis requires models to be relatively simple, but models must still capture the nature and dynamics of the system. With the Ensemble Kalman Filter, we are able to capture complex dynamics in multispecies models with models simple enough to allow further bioeconomic analysis. While bioeconomic analysis has had limited influence on management decisions, the advent of new methods and the need for high dimensional ecosystem based management models may make bioeconomic research more relevant in the future. The filter is applied to a ecosystem model of the commercially most important species in the Barents Sea. The simpler, aggregated stochastic biomass models capture the complex dynamics of the pelagic stocks on the level needed for making decisions on for example allowable catches.

Do Species Interactions and Stochasticity Matter to Optimal Management of Multispecies Fisheries

The multispecies fisheries management looks at a bigger picture in addressing the long-term consequences of present decisions. This implies an ecosystem management that includes a number of species and their physical, biological and economic interactions. These interactions make the growth of resources stochastic and increase complexity in understanding stock dynamics and optimal catch for such a stochastic and multiple stocks´ system. To address the issue of identifying optimal catch of stochastically growing multi stocks, we have formulated and applied a time-continuous stochastic model. The model contributes to multispecies bioeconomic management of marine ecosystems. An application of model in a predator-prey relationship in Barent Sea revealed that the optimal catch for stochastically growing stocks in a multispecies interaction model is different from the deterministic model.

Analyzing Risk of Stock Collapse in a Fishery Under Stochastic Profit Maximization

In commercial fisheries, stock collapse is an intrinsic problem caused by overexploitation or due to pure stochasticity. To analyze the risk of stock collapse, we apply a relatively simple Monte Carlo approach which can capture complex stock dynamics. We use an economic model with downward sloping demand and stock dependent costs. First, we derive an optimal exploitation policy as a feedback control rule and analyze the effects of stochasticity. We observe that the stochastic solution is more conservative compared to the deterministic solution at low level of stochasticity. For moderate level of stochasticity, a more myopic exploitation is optimal at small stock and conservative at large stock level. For relatively high stochasticity, one should be myopic in exploitation. Then, we simulate the system forward in time with the optimal solution. In simulated paths, some stock recovered while others collapsed. From the simulation approach, we estimate the probability of stock collapse and characterize the long term stable region.

Spatial Management of a Fishery Under Parameter Uncertainty

Spatial management of a fishery under parameter uncertainty is analyzed. The habitat is divided into two areas, and the effort level in the two areas may be different. The migration of biomass between the areas follows a diffusion process; two different specifications are considered. The model features logistic growth and Schaefer production functions. The intrinsic growth rate is treated as uncertain; the uncertainty is symmetric and spatially homogeneous. It is found that the optimal, spatial distribution of effort with respect to expected harvest is neither homogeneous or heterogeneous everywhere, but homogenous for a given subset of the parameter space and heterogeneous elsewhere.

Stochastically Induced Critical Depensation and Risk of Stock Collapse

ABSTRACT This article investigates the risk of stock collapse due to stochastically induced critical depensation in managed fisheries. We use a continuous-time surplus production model and an economic model with downward-sloping demand and stock-dependent costs. First, we derive an optimal exploitation policy as a feedback control rule by applying the Hamilton-Jacobi-Bellman approach and analyze the effects of stochasticity on the optimal policy. Then, we characterize the long-term sustainable optimal state and estimate the risk of stock collapse due to stochastically induced critical depensation. We find that the optimal harvest policy in the stochastic setting is conservative at low stochasticity and approaches the myopic solution at high stochasticity. The risk of stock collapse is increasing with the stochasticity and decreasing with stock sizes. JEL Codes: C61, Q22, Q57.

Concerns among local government facility managers: a Norwegian survey

Purpose To investigate which concerns are most important for local government facility managers in Norway. Design/methodology/approach We analyze a survey dataset covering about 2/3 of all Norwegian local governments and 80 percent of the Norwegian population. We consider both descriptive statistics and results from an ordered probit regression analysis. Findings Facility managers are most concerned about weak fiscal conditions and lack of political priority of facility management, and local governments reporting public buildings in good condition generally have fewer and less serious concerns. Further, managers in municipalities with a solid fiscal balance are less concerned both about how tight fiscal conditions and lack of political prioritization affect facility management. Managers in municipalities with a centralized facility management structure are less concerned that the organizational structure of the facility management is sub-optimal. Finally, managers in populous municipalities have less conc...

On the ranking of critical success factors: The role of cost efficiency and score uncertainty for public facilities management

Purpose The purpose of this paper is to discuss rankings of critical success factors (CSFs) from survey data, both with respect to what information such rankings should be based on and how to evaluate and interpret uncertainty from sampling errors. Design/methodology/approach The authors conducted a survey on CSFs in public facilities management. The survey data set covers two-thirds of all Norwegian local governments and 80 per cent of the Norwegian population. The authors analyze the data using basic statistics and bootstrap sampling techniques. Findings Rankings of CSFs are sensitive to the information one chooses to collect in the survey. With the survey data, the authors show that the typical approach of inquiring about importance of various factors leads to a different ranking of factors than if one inquires about cost efficiency. The authors further consider a ranking that reflects all information in the data; the authors look in particular at a ranking with equal weights to importance and cost efficiency. The authors also find that many factors, when controlling for sampling error, should be ranked equally, and that further considerations need to be consulted when priorities are decided. Originality/value The authors demonstrate the effect of cost efficiency and uncertainty considerations on rankings of CSFs for facilities management. The study paves the way for a broader and more comprehensive perspective on CSFs and what these factors should and could reflect.