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This paper discusses the conditions for generalizing the analysis in Weitzman (1974) to fisheries. It is shown that it is straightforward to generalize the analysis if the cost function is direct additively separable in stock size and catches. This leads to the conclusion that the analysis holds for a schooling fishery with and without search costs, but it might not hold for a search fishery. A further result is that for a schooling fishery without search costs, where the marginal cost function is steeper than the marginal benefit function, taxes are likely to be preferred over individual transferable quotas.

A bstract We present a measurement of the doubly radiative decay η → π 0 γγ based on a sample of 82 million η mesons produced in the e + e − → ϕ → ηγ process at the Frascati ϕ -factory DAΦNE. From the data analysis, 1246 ± 133 signal events were observed. By normalising the signal to the well-known η → 3 π 0 decay the branching fraction is measured to be (0 . 98 ± 0 . 11 stat ± 0 . 14 syst ) × 10 − 4 . This result agrees with a preliminary KLOE measurement, but is a factor of two smaller than the current world average. Results for d Γ( η → π 0 γγ ) /dM 2 ( γγ ) are also presented and compared with the latest theoretical predictions.

We present a measurement of the doubly radiative decay η → π0γγ based ona sample of 82 million η mesons produced in the e+e− → ϕ → ηγ process at the Frascatiϕ-factory DAΦNE. From the data analysis, 1246 ± 133 signal events were observed. Bynormalising the signal to the well-known η → 3π0 decay the branching fraction B(η → π0γγ) ismeasured to be (0.98 ± 0.11stat ± 0.14syst) × 10−4. This result agrees with a preliminary KLOEmeasurement, but is a factor of two smaller than the current world average. Results for dΓ(η →π0γγ)/dM 2(γγ) are also presented and compared with the latest theoretical predictions.

The paper shows that explicit modelling of sunk cost and a firm’s entry-exit decision in a traditional deterministic investment model may give an explanation of the slow transition to the optimal fleet structure following the introduction of individual transferable quotas (ITQs). The analysis shows that the annual lease unit price of quota may be in a range where the long-run fleet structure will not be attainable at once. Over time, firms with zero gross investment as optimal behavior may leave the industry as the capital decays and over the transition period the optimal fleet structure prevails. (JEL Q22)

The specification of a convex production technology is a potential issue in estimating firm-level Johansen plant capacity utilisation rates and their subsequent use in the short-run Johansen industry capacity model of the fishery. There are different plant capacity utilisation estimates with convex and non-convex technologies. When entered as parameters in the short-run Johansen industry model, this leads to different distributions in the activity vectors. With non-convex technology, more vessels remain active in the fleet, and there is no longer an overestimation of the number of decommissioned vessels compared to the use of a convex technology. A second methodological reflection involves a way to trace the evolution of capacity over time and the possibility of formulating multi-period, short-run Johansen industry models using appropriate discrete time Malmquist productivity indices. Danish vessels provide an illustration for the convexity issue.

The cod stock in the North Sea is threatened by overexploitation. To recover this fishing stock, pressure needs to be reduced. This implies that catch compositions with small amounts of cod are preferred by public policy makers. The present analysis assesses the technological efficiency of fishing trips in terms of the substitution possibilities away from cod by considering landings of cod as an undesirable output. A conservative non-parametric frontier technology approach imposing minimal assumptions and based on directional distance functions is applied to explore alternative fishing activities for Danish gill netters operating in the North Sea with the goal of reducing cod catches. Since performance on different fishing trips may be influenced by the operating environment, a four-stage approach is applied to correct for exogenous factors (Fried et al., J Product Anal 12(3):249–267, 1999). The corrected directional distance function efficiency scores reveal the behavioural inefficiencies, i.e., prospects for decreasing the catch of cod while catch of other species are increased.

Denmark started development of its national hazardous waste management system in 1971,and since then the system has been continuously developed as a result of technical and political changes. This paper describes the development of this national registration, collection and treatment system for oil-and chemical wastes, seen from an operator's point of view. Development in waste amount is presented and commented on based on the corresponding political and legal actions taken due to the increased environmental concern in the country. Trends in development of alternative treatment and recycling facilities resulting from technological developments and economical incentives are mentioned.

The economic efficiencies of the Danish, Icelandic, and Norwegian cod fisheries are examined. For this purpose, nonlinear aggregate models of these fisheries are constructed. Comparing the calculated optimal harvest and biomass quantities with the actual fisheries provides a measure of the degree of efficiency in these fisheries. The comparisons confirm that the cod harvesting policies of these countries have been hugely inefficient in the past. It appears that inefficiency has been increasing over the last three to four decades, even after TAC regulations replaced open access, indicating that the management policies adopted by all three countries have failed to cure overfishing.

A formal economic analysis of the discarding problem is presented, focusing on the individual fisherman and the effect of different regulations on the fisherman's incentives to discard. It is shown that in a nonregulated fishery, either multispecies or single species/multisize, where the only constraints are the hold capacity and the length of the season, the fisherman may have rational incentives to discard/highgrade, if the marginal trip profit of an extra fishing day is greater than the average trip profit. Regulation by TAC does not change the incentives to discard. However, under INTQs and ITQs, the incentives to discard increase. The incentives to discard decrease under ITQs compared to INTQs, if the unit quota price is smaller than the shadow price of the quota. The model is applied to the Greenland shrimp fishery, where it demonstrates the reported discard behavior in the fishery. Finally, different regulations of discard are applied and discussed in the model. The analysis suggests that regulation of fishing days could be a promising alternative to usual suggested measures like tax/subsidies and landings obligations.

This paper presents a bioeconomic analysis determining the resource rent and optimum effort of the shrimp (Pandalus borealis) fishery in the Davis Strait, taking into account the discard behaviour of the fleet. It is demonstrated that, from an economic point of view, the shrimp stock in the Davis Strait is substantially overfished. In order to obtain the maximum economic yield, the effort must be reduced by at least 40% compared to the effort level of 1991. The gain in resource rent by reducing effort is estimated to be at least 20% compared to the resource rent of 1991.