TECHNOLOGY AND MANAGEMENT IN MAURITANIAN CEPHALOPOD FISHERIES

If the technology in a multi-species fishery is such that there is jointness in inputs and non-separability between inputs and outputs, then management on a species-by-species basis may lead to unintended outcomes, including over-exploitation of the resource. This study investigates the nature of the technical and economic relationships underlying the 1989-1990 Mauritanian cephalopod fishery by estimating a system of dual output supply functions derived from a generalized Leontief revenue function. Model results indicate the existence of jointness in inputs and non-separability between inputs and outputs in the fishery. Cross-price elasticities indicated a number of substitute and complementary relationships, with these relationships changing in magnitude across years. Taken together, the results suggest that any attempts to economically manage the resource should be based on multi-product production theory, not single-species biological response functions. Besides ruling out single-species management, the dominance of substitute relationships in the Mauritanian cephalopod fishery precludes the use of "key species" management of the entire resource.Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy,

Variations colorées chez les céphalopodes selon l'environnement physique et social: un point de vue cognitif

National audienceLes variations colorées des céphalopodes sont le plus souvent considérées à la lumière de leur fonction adaptative : se dissimuler des prédateurs, être un chasseur « invisible ». Un approfondissement de la connaissance de ces animaux révèle que les changements de couleur répondent à trois contextes différents : homochromie avec l'environnement, émotion (peur, agressivité...) et relations intraspécifiques. Dans ce travail, nous montrons les limites d'une explication « tout adaptative » mais aussi les limites d'une explication basée sur la communication. Nous proposons comme complément et/ou alternative une approche cognitive tensive basée sur le postulat d'un certain « être au monde » de la pieuvre renouant en cela avec la tradition phénoménologique de l'Umwelt

TECHNOLOGY AND MANAGEMENT IN MAURITANIAN CEPHALOPOD FISHERIES

If the technology in a multi-species fishery is such that there is jointness in inputs and non-separability between inputs and outputs, then management on a species-by-species basis may lead to unintended outcomes, including over-exploitation of the resource. This study investigates the nature of the technical and economic relationships underlying the 1989-90 Mauritanian cephalopod fishery by estimating a system of dual output supply functions derived from a generalized Leontief revenue function. Model results indicate the existence of jointness in inputs and non-separability between inputs and outputs in the fishery. Cross-price elasticities indicated a number of substitute and complementary relationships, with these relationships changing in magnitude across years. Taken together, the results suggest that any attempts to economically manage the resource should be based on multi-product product production theory, not single-species biological response functions. Besides ruling out single-species management, the dominance of substitute relationships in the Mauritanian cephalopod fishery precludes the use of "key species" management of the entire resource.Resource /Energy Economics and Policy,