Daniel Pauly May 2004 Competition between Marine Mammals and Fisheries : FOOD FOR THOUGHT

Figure 1. Who Eats How Much of WHAT? Estimated mean annual global catch/food consumption of marine mammals and fisheries by 9 major food types during an average year in the 1990s expressed as proportions of total (from Kaschner, 2004) 138. The percentages of different food types in marine mammal consumption were computed based on diet composition standardised across species 96. Corresponding percentages of different food types in fisheries catches were obtained by assigning individual target species/taxa to the appropriate food type category based on life history, size and habitat preferences of the target species or taxa. Food types mainly consumed by marine mammals are presented in hues of blue and green, and food types that are major fisheries target groups are presented in yellows and reds. Note that food types primarily targeted by fisheries represent only a small proportion of the diet of any marine mammal group. 3 As the current crisis of global fisheries worsens, the case has been increasingly put forward in international fora that culling marine mammals would not only resolve the problems of fisheries but also help alleviate world hunger. Here, we present results from modelling the degree of ecological food resource overlap on a global scale between marine mammals and fisheries; the model considers the types of food taken by each group, as well as the geographic areas where the food is taken. Our analysis clearly shows that there is no evidence that food competition between the two is a global problem, even when the uncertainties associated with the available information are considered. Consequently, there is little basis to blame marine mammals for the crisis world fisheries are facing today. There is even less support for the suggestion that we could solve any of these urgent global problems, caused by a long history of mismanagement of fisheries, by reducing marine mammal populations. The claims of competition promoted by culling advocates are usually based on estimates of the total food consumed annually by all or some species of marine mammals, which—depending on the geographic scale and species considered—amount to several times more than the annual catches taken by the fisheries. It is then implied that the amounts consumed would be available Executive Summary 4 2A 2B 2C 2D Figure 2. Where Do They Meet? Maps of estimated spatially explicit resource overlap between baleen whales and fisheries (A), pinnipeds and fisheries (B), large toothed whales and fisheries …