Estimating Heterogeneous Primal Capacity and Capacity Utilization Measures in a Multi-Species Fishery

We use a stochastic production frontier model to investigate the presence of heterogeneous production and its impact on fleet capacity and capacity utilization in a multi-species fishery. Furthermore, we propose a new fleet capacity estimate that incorporates complete information on the stochastic differences between each vessel-specific technical efficiency distribution. Results indicate that ignoring heterogeneity in production technologies within a multi-species fishery, as well as the complete distribution of a vessel's technical efficiency score, may yield erroneous fleet-wide production profiles and estimates of capacity.Resource /Energy Economics and Policy,

Angler Heterogeneity and the Species-Specific Demand for Marine Recreational Fishing

In this study we assess the viability of single-species recreation demand models given commonly available data sets. Using the 2000 MRFSS southeast intercept data combined with the economic add-on, we determine that the MRFSS data will support only a few species-specific recreation demand models. Considering species of management interest in the southeast, we focus on dolphin, king mackerel, red snapper and red drum. We examine single-species recreational fishing behavior using random utility models of demand. We explore mixed logit (i.e., random parameter) logit and finite mixture (i.e., latent class logit) models for dealing with angler heterogeneity. We compare these to the commonly used conditional and nested logit models in terms of the value of catching (and keeping) one additional fish. Mixed logit models illustrate that the value of catch can be highly heterogeneous and, in some cases, can include both positive and negative values. The finite mixture model generates value estimates that were some times strikingly different than conditional, nested and mixed logit models. Preference heterogeneity is significant within the MRFSS data. We find evidence that single-species models outperform multiple species models and recreational values differ. Key Words: marine recreational fishing, single-species demand, preference heterogeneity models

Hyperketonaemia risk lower in organic cows housed in free stalls

The variation in the incidence of hyperketonaemia is marked between individual herds, and even though organic farms have some feeding related factors predisposing to hyperketonaemia, there are also some management practices (especially in loose housing systems) which might act as preventive factors. However, it may be advisable for organic farmers to favour moderate milk production when selecting cows for a herd

Fixed-Effect Estimation of Highly-Mobile Production Technologies

We consider fixed-effect estimation of a production function where inputs and outputs vary over time, space, and cross-sectional unit. Variability in the spatial dimension allows for time-varying individual effects, without parametric assumptions on the effects. Asymptotics along the spatial dimension provide consistency and normality of the marginal products. A finite-sample example is provided: a production function for bottom-trawler fishing vessels in the flatfish fisheries of the Bering Sea. We find significant spatial variability of output (catch) which we exploit in estimation of a harvesting function

Fixed-Effect Estimation of Highly-Mobile Production Technologies

We consider fixed-effect estimation of a production function where inputs and outputs vary over time, space, and cross-sectional unit. Variability in the spatial dimension allows for time-varying individual effects, without parametric assumptions on the effects. Asymptotics along the spatial dimension provide consistency and normality of the marginal products. A finite-sample example is provided: a production function for bottom-trawler fishing vessels in the flatfish fisheries of the Bering Sea. We find significant spatial variability of output (catch) which we exploit in estimation of a harvesting function

Estimating Heterogeneous Capacity and Capacity Utilization in a Multi-Species Fishery

We use a stochastic production frontier model to investigate the presence of heterogeneous production and its impact on fleet capacity and capacity utilization in a multi-species fishery. Furthermore, we propose a new fleet capacity estimate that incorporates complete information on the stochastic differences between each vessel-specific technical efficiency distribution. Results indicate that ignoring heterogeneity in production technologies within a multi-species fishery, as well as the complete distribution of a vessel’s technical efficiency score, may yield erroneous fleet-wide production profiles and estimates of capacity. Furthermore, our new estimate of capacity enables out-of-sample production predictions predicated on either homogeneity or heterogeneity modeling which may be utilized to facilitate policy

Strategic Substitutes or Complements? The Game of Where to Fish

The ‘‘global game with strategic substitutes and complements’’ of Karp et al. (2007) is used to model the decision of where to fish. A complete information game is assumed, but the model is generalized to S \u3e 1 sites. In this game, a fisherman’s payoff depends on fish density in each site and the actions of other fishermen which can lead to congestion or agglomeration effects. Stable and unstable equilibria are characterized, as well as notions of equilibrium dominance. The model is applied to the Alaskan flatfish fishery by specifying a strategic interaction function (response to congestion) that is a non-linear function of the degree of congestion present in a given site. Results suggest that the interaction function may be non-monotonic in congestion

Identifying Technically Efficient Fishing Vessels: A Non-Empty, Minimal Subset Approach

There is a growing resource economics literature, concerning the estimation of the technical efficiency of fishing vessels utilizing the stochastic frontier model. In these models, vessel output is regressed on a linear function of vessel inputs and a random composed error. Using parametric assumptions on the regression residual, estimates of vessel technical efficiency are calculated as the mean of a truncated normal distribution and are often reported in a rank statistic as a measure of a captain’s skill and used to estimate excess capacity within fisheries. We demonstrate analytically that these measures are potentially flawed, and extend the results of Horrace (2005) to estimate captain skill for thirty nine vessels in the Northeast Atlantic herring fleet, based on homogenous and heterogeneous production functions within the fleet. When homogenous production is assumed, we find inferential inconsistencies between our methods and the methods of ranking the means of the technical inefficiency distributions for each vessel. When production is allowed to be heterogeneous, these inconsistencies are mitigated

Estimating Heterogeneous Production in Fisheries

Stochastic production frontier models are used extensively in the agricultural and resource economics literature to estimate production functions and technical efficiency, as well as to guide policy. Traditionally these models assume that each agent’s production can be specified as a representative, homogeneous function. This paper proposes the synthesis of a latent class regression and an agricultural production frontier model to estimate technical efficiency while allowing for the possibility of production heterogeneity. We use this model to estimate a latent class production function and efficiency measures for vessels in the Northeast Atlantic herring fishery. Our results suggest that traditional measures of technical efficiency may be incorrect, if heterogeneity of agricultural production exists