Seafood is a growing part of the economy, but its economic value is diminished by marine diseases. Infectious diseases are common in the ocean, and here we tabulate 67 examples that can reduce commercial species' growth and survivorship or decrease seafood quality. These impacts seem most problematic in the stressful and crowded conditions of aquaculture, which increasingly dominates seafood production as wild fishery production plateaus. For instance, marine diseases of farmed oysters, shrimp, abalone, and various fishes, particularly Atlantic salmon, cost billions of dollars each year. In comparison, it is often difficult to accurately estimate disease impacts on wild populations, especially those of pelagic and subtidal species. Farmed species often receive infectious diseases from wild species and can, in turn, export infectious agents to wild species. However, the impact of disease export on wild fisheries is controversial because there are few quantitative data demonstrating that wild species near farms suffer more from infectious diseases than those in other areas. The movement of exotic infectious agents to new areas continues to be the greatest concern.

Résumé / AbstractCette étude s'intéresse à des aspects méthodologiques associés à l'utilisation d'expériences avec choix discrets pour évaluer des biens publics. Nous avons développé un modèle explicite de jeux théoriques pour des décisions individuelles à des séries de choix, avec conditions générales sous lesquelles un questionnaire avec des choix binaires répétés incite la révélation des valeurs. Ce développement théorique est suivi d'expériences terrains avec traitements qui couvrent le spectre des incitatifs de la révélation des valeurs, passant de la décision avec mise en place réelle du projet et paiements réels de la part des participants, à celle sans aucune conséquence financière directe et avec projets hypothétiques. Les résultats indiquent qu'il est possible d'obtenir une révélation des valeurs réelles en situation hypothétique, si les participants pensent que leurs décisions ont un potentiel d'impact significatif sur une éventuelle politique.

In an effort to attenuate human-wildlife conflict and promote conservation of charismatic megafauna, compensation programs for wildlife damages have been implemented in many countries. Compensating pastoralists and farmers for damage caused by wildlife reduces hunting pressure on wild animal populations. However, it can also lead to a decrease in efforts to prevent damage and exacerbate conflicts with wildlife. Furthermore, compensation programs increase the return to agriculture and can therefore be viewed as a subsidy toward crop and livestock production. Such subsidies can trigger agricultural expansion (and habitat conversion), an inflow of agriculture producers, and intensification of agricultural production. Each of these impacts is shown to have potentially adverse effects on the wildlife population that compensation intends to favor. In some circumstances, the net effect on the wildlife stock could be negative. This calls for a careful assessment of local ecological and economic conditions before compensation is implemented. Incentive mechanisms that are directly tied to conservation outcomes (e.g., payments to locals based on the size of the wildlife population) should be considered instead of compensation programs. JOURNAL OF WILDLIFE MANAGEMENT 69(1):14-19; 2005

Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in Matching and Challenge Gifts to Charity: Evidence from Laboratory and Natural Field ExperimentsDaniel Rondeau John A. List The Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between science, politics and business. IZA is an independent nonprofit organization supported by Deutsche Post World Net. The center is associated with the University of Bonn and offers a stimulating research environment through its international network, workshops and conferences, data service, project support, research visits and doctoral program. IZA engages in (i) original and internationally competitive research in all fields of labor economics, (ii) development of policy concepts, and (iii) dissemination of research results and concepts to the interested public. D I S C U S S I O N P A P E R S E R I E SIZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character. A revised version may be available directly from the author. This study designs a natural field experiment linked to a controlled laboratory experiment to examine the effectiveness of matching gifts and challenge gifts, two popular strategies used to secure a portion of the $200 billion annually given to charities. We find evidence that challenge gifts positively influence contributions in the field, but matching gifts do not. Methodologically, we find important similarities and dissimilarities between behavior in the lab and the field. Overall, our results have clear implications for fundraisers and provide avenues for future empirical and theoretical work on charitable giving. JEL Classification:C93, H41