Since the theory of evolution by natural selection was first postulated, biologists have noted that life histories evolve following broad patterns across all organisms. Understanding the mechanisms causing these relationships is the central focus of life history theory; these insights can also be used to better estimate the biology and extinction risk of data-poor species. Sharks, rays, and chimaeras (class Chondrichthyes) are an ideal taxon to explore these relationships as they have evolved a broad range of life history strategies. In this thesis, I focus on two key time-related life history parameters that are often used as a measure of productivity: growth coefficient k, which is estimated from the von Bertalanffy growth function (VBGF), and maximum intrinsic rate of population increase rmax, estimated by simplifying the Euler-Lotka equation. I begin by clarifying two methodological problems regarding the estimation of growth and productivity. I first show that fixing the y-intercept in the VBGF, a common approach in chondrichthyan age and growth studies, often causes considerable bias in growth coefficient estimates, and recommend using the three-parameter VBGF instead. I then point out an important omission in a method commonly used for estimating r max in chondrichthyans and clarify the correct way to estimate it. Next I explore the effect of uncertainty on the estimation of r max and show that species with low annual reproductive outputs are bound to have very low productivities, thus focus should be placed into accurately estimating litter sizes, breeding intervals, and the variability of these traits. As an example of how these insights can be applied, I better estimate growth and productivity for a data sparse species of conservation concern, the Spinetail Devil Ray (Mobula japanica), and show it has a much lower somatic growth rate than previously thought and one of the lowest productivities among chondrichthyans. Finally, I show that productivity in chondrichthyans varies with temperature as well as depth, and that the scaling of this relationship changes with temperature according to the expectation from Bergman's rule. My thesis demonstrates that simple insights from life history theory can further our knowledge on the broad patterns that shape the evolution of life histories we see today, which can be used to inform management of data-poor species.

The Biology of Sharks and Rays is a comprehensive resource on the biological and physiological characteristics of the cartilaginous fishes: sharks, rays, and chimaeras. In sixteen chapters, organized by theme, A. Peter Klimley covers a broad spectrum of topics, including taxonomy, morphology, ecology, and physiology. For example, he explains the body design of sharks and why the ridged, toothlike denticles that cover their entire bodies are present on only part of the rays’ bodies and are absent from those of chimaeras. Another chapter explores the anatomy of the jaws and the role of the muscles and teeth in jaw extension, seizure, and handling of prey. The chapters are richly illustrated with pictures of sharks, diagrams of sensory organs, drawings of the body postures of sharks during threat and reproductive displays, and maps showing the extent of the species’ foraging range and long-distance migrations. Each chapter commences with an anecdote from the author about his own personal experience with the topic, followed by thought-provoking questions and a list of recommended readings in the scientific literature. The book will be a useful textbook for advanced ichthyology students as well as an encyclopedic source for those seeking a greater understanding of these fascinating creatures.

Maligned and misunderstood, sharks are possibly the most feared, yet the most fascinating sea creatures. Of about 350 known species of shark, only a handful are a threat to humans. In reality, it is humans who pose the greater threat, hunting and fishing some species to the verge of extinction. Diverse in appearance, they range from the tiny cookiecutter or cigar shark, to the massive whale shark. Stranger still are the rays, with names such as the banded stingaree and the Javanese cownose ray. Curiously shaped like craft from outer space, some are so highly colored they could be the creation of a whimsical painter. This book represents the most up-to-date information and thinking on our understanding of these extraordinary inhabitants of the deep - their highly developed senses and intellect, and their ecology, biology, and behavior. What is being done to protect them? In what ways are they still being exploited? Sharks and Rays highlights the advances being made in shark and ray conservation.

Explores the world of one of the most fascinating, frightening creatures on the planet, offering a compelling look at the shark's often misunderstood life in the wild.

This volume presents a fully illustrated field guide for the identification of the sharks and rays most relevant to the fisheries of the Mediterranean and Black Sea. An extensive literature review was carried out for the preparation of this document. A total of 49 sharks, 34 batoids and 1 chimaera are fully treated. The presence of 5 sharks and 2 batoids included in this field guide, need, however, to be confirmed. The guide includes sections on technical terms and measurements for sharks and batoids, and fully illustrated keys to those orders and families that occur in the region. Each species account includes: at least one annotated illustration of the species highlighting its relevant identification characters; basic information on nomenclature, synonyms and possible misidentifications; FAO common names; basic information on size, habitat and biology, distribution, importance to fisheries, and conservation and exploitation status.

From the bestselling author of Jaws comes a firsthand guide to one of the most feared—and often misunderstood—animals: sharks! In direct and accessible prose, Peter Benchley sets the record straight about the many types of sharks (including the ones that pose a genuine threat to us), the behavior of sharks and other sea creatures we fear, the odds against an attack, and how to improve them even further. He also teaches us how to swim safely in the ocean by reading the tides and currents and respecting all the inhabitants. Here are the lessons Peter has learned, the mistakes he has made, the danger he has faced—and the spectacular sights he has seen in the world’s largest environment. The book includes 16 pages of black-and-white photographs.