Sharks of the open ocean: biology, fisheries and conservation

...I had the pleasure of serving as keynote speaker at the International Pelagic Shark Workshop, held at the beautiful Asilomar oceanfront retreat in Pacific Grove, California, in February 2000, which eventually led to this book. Using then current knowledge, as incorporated in FishBase, the online encyclopedia of fishes, I presented a review of shark growth and natural mortality patterns that, I suggested, were regular enough to allow inferences on the life-history parameters of well-studied species to be applied to understudied species, via their maximum size and taxonomic affinities. By implication, this suggested that we should concentrate our research on other aspects of shark fisheries biology, such as mapping their catches, including the bycatch of various tuna fisheries and the catch of illegal fisheries. This book, introduced through the reviews of shark biodiversity, biology, and reproduction in Part I, shows that I was both a bit wrong, and a little bit right. I was wrong, in part, because the contributions in Part II – devoted to the growth, mortality, reproduction, and other aspects of the biology of 11 species of open ocean sharks – offer a wealth of new information, which will considerably improve our ability to make inferences about lesser-known species. The first three chapters in Part IV further enhance our understanding of pelagic sharks by providing specific and comparative life-history parameters for these species. Taken together, these contributions confirm that pelagic elasmobranchs, despite their wide distribution and the spectacular transoceanic migrations that some have exhibited, are extremely vulnerable to fishing, and that there is a critical need for protection of pelagic sharks and rays. I was a little bit right because, as Part III demonstrates, our knowledge of shark catches is scandalously limited. Although species-specific catch and discard data for pelagic sharks are still incomplete, the catch and bycatch studies herein begin to fill the information gap, especially as they cover not only the much-studied Atlantic, but also the Pacific and the often neglected Indian Ocean. The contributions in Part IV focus on methods to improve our understanding of pelagic sharks. They present a diverse set of tools, including demographic parameter analysis, genetic techniques, tagging methods and data analysis, and mathematical models for assessing stock structure, movements, and status. These contributions were included in the book because they are particularly useful for addressing the unique data constraints and life-history modes exhibited by pelagic sharks. The contributions in Part V confront the conservation and management outlook for pelagic sharks, and will be extremely useful to scientists, managers, and conservationists in government agencies, fishery groups, and nongovernmental organizations who are working to stop the widespread decline of pelagic shark populations. Yet I suspect one ingredient needs to be added to this mix: more public information and involvement...