The decisions animals make about how long to wait between activities can determine the success of diverse behaviours such as foraging, group formation or risk avoidance. Remarkably, for diverse animal species, including humans, spontaneous patterns of waiting times show random 'burstiness' that appears scale-invariant across a broad set of scales. However, a general theory linking this phenomen...

Analysis of maximum depth of occurrence of 11 952 marine fish species shows a global decrease in species number (N) with depth (x; m): log10 N = -0·000422x + 3·610000 (r(2)  = 0·948). The rate of decrease is close to global estimates for change in pelagic and benthic biomass with depth (-0·000430), indicating that species richness of fishes may be limited by food energy availability in the deep...

World demand for high quality protein foods has stimulated a rapid development of intensive iish culture techniques. Inherent with the intensive rearing of fish are related problems of high loading densities, declining water quality, adequate diets, handling, and disease control. Man has only recently recognized the threat imposed by disease and its limitation on economic development of the aqu...

Most fishes are poikilothermic-Le. their body temperature is within a few degrees of ambient unless ambient is changing rapidly. The exceptions are certain sharks and true tunas. Little is known about the locomotion and energetics of warm-bodied sharks. Our review focuses on a few species of tunas but draws on information from other fish (especially salmonids) to fill in the gaps in our underst...

Ecological risk assessments (ERAs) are employed to quantify and predict the vulnerability of a particular species, stock or population to a specific stressor, e.g. pollution, harvesting, climate change, by-catch. Data generated from ERAs are used to identify and prioritize species for implementation of effective conservation and management strategies. At this time, ERAs are of particular import...

Chondrichthyes, which include Elasmobranchii (sharks and batoids) and Holocephali (chimaeras), are a relatively small group in the Mediterranean Sea (89 species) playing a key role in the ecosystems where they are found. At present, many species of this group are threatened as a result of anthropogenic effects, including fishing activity. Knowledge of the spatial distribution of these species i...

Early morphological studies regarding the evolutionary history of elasmobranchs suggested sharks and batoids (skates and rays) were respectively monophyletic. More modern morphological cladistic studies, however, have tended to suggest that batoids are derived sharks, closely related to sawsharks and angelsharks, a phylogenetic arrangement known as the Hypnosqualea hypothesis. Very few molecula...

To investigate the physical mechanism of the electric sense, we present an initial electrical characterization of the glycoprotein gel that fills the electrosensitive organs of marine elasmobranchs (sharks, skates, and rays). We have collected samples of this gel, postmortem, from three shark species, and removed the majority of dissolved salts in one sample via dialysis. Here we present the re...

The PFRP was host to “Tagging and Tracking Marine Fish with Electronic Devices,” a major international symposium held at the East-West Center in Honolulu from February 7–11, 2000. More than 100 scientists and electronics manufacturers from a dozen countries assembled to share their findings and discuss the state-of-the-art in this rapidly developing field. Results from all of earth’s oceans wer...

BACKGROUND Modern selachians and their supposed sister group (hybodont sharks) have a long and successful evolutionary history. Yet, although selachian remains are considered relatively common in the fossil record in comparison with other marine vertebrates, little is known about the quality of their fossil record. Similarly, only a few works based on specific time intervals have attempted to i...