Sharks, rays, and chimaeras (Class Chondrichthyes; herein 'sharks') are the earliest extant jawed vertebrates and exhibit some of the greatest functional diversity of all vertebrates. Ecologically, they influence energy transfer vertically through trophic levels and sometimes trophic cascades via direct consumption and predation risk. Through movements and migrations, they connect horizontally and temporally across habitats and ecosystems, integrating energy flows at large spatial scales and across time. This connectivity flows from ontogenetic growth in size and spatial movements, which in turn underpins their relatively low reproductive rates compared with other exploited ocean fishes. Sharks are also ecologically and demographically diverse and are taken in a wide variety of fisheries for multiple products (e.g. meat, fins, teeth, and gills). Consequently, a range of fisheries management measures are generally preferable to 'silver bullet' and 'one size fits all' conservation actions. Some species with extremely low annual reproductive output can easily become endangered and hence require strict protections to minimize mortality. Other, more prolific species can withstand fishing over the long term if catches are subject to effective catch limits throughout the species' range. We identify, based on the IUCN Red List status, 64 endangered species in particular need of new or stricter protections and 514 species in need of improvements to fisheries management. We designate priority countries for such actions, recognizing the widely differing fishing pressures and conservation capacity. We hope that this analysis assists efforts to ensure this group of ecologically important and evolutionarily distinct animals can support both ocean ecosystems and human activities in the future.

Significant changes have occurred in the well‐established partnership between fisheries managers and geneticists over the last 50 years. It is therefore timely to review and recalibrate the ways in which genetic technologies can assist the fishing industry to maintain productive and sustainable harvests. Our objective is to contribute to the mutual understanding of all stakeholders in the genetics–management partnership. Genetic technologies that are relevant to fisheries management are grouped into eleven themes, which are described in plain language for a non‐specialist audience. The role that the genetic information plays in fisheries management is explained, along with an assessment of the challenges and barriers that may be preventing the uptake of the information into the fisheries management process. The compelling conclusion is that genetics offers a diverse collection of versatile and useful tools for informing fisheries managers about issues that have a biological basis. Presently, mainstream use of genetic tools focuses on a narrow set of fisheries management issues, but the diversity of genetic tools and the novel issues they can address indicates that uptake will grow, particularly as communication between geneticists and end‐users improves.

Pre-contact avifaunal extinctions in Hawai'i generally have been attributed to human predation and/or landscape alteration by colonizing Polynesians. However, until recently there have been insufficient data for evaluating mostof the important variables involved in this issue. This situation has changed with recent archaeological, paleontological, and wetland coring research conducted on O'ahu's 'Ewa Plain, a hot, dry emerged limestone reef characterized by numerous sinkholes. The main evidence obtained from this research includes (I) wetland coring data that stratigraphically demonstrate forest decline before any burning, (2) radiocarbon dating of bonesof rats and extinctbirds that provides a time frame for their occurrence unavailable from stratified deposits, and (3) the radiocarbon-based history of human settlement of the 'Ewa Plain.Based on this evidence the argument is made that (I) at least some major avian extinctions occurred within the period immediately following Polynesian colonization, (2) theseextinctions were due primarily to the rapid decline of their native lowland forest habitat, (3) human settlement of the 'Ewa Plain occurred after native forest collapse, not coincident with it, and (4) the main source of destruction of the native forests was the introduced Polynesian rat, Rattus exulans, not Hawaiian agricultural clearing and burning. This model also explains the absence of largequantities of bird bone in early sites (in contrast to other places in Polynesia and Micronesia), and the absence in early middens of many plants (notably Kanaloa kahoolawensis) that were common in the native forest.

Commercially fished holothurians have important functions in nutrient recycling, which increasesthe benthic productivity of coral reef ecosystems. Thus, removal of these animals through fishing may reduce the overall productivity of affected coral reefs. To investigate the potential for recovery of overfished holothurian ( Holothuria nobilis) stocks on the Great Barrier Reef (GBR), we (1) conducted field surveys on 23 reefs after fishery closure, (2) modeled total virgin biomass and compared it with the total amount fished, and (3) estimated individual growth rates with a DNA fingerprinting technique. Two years after fishery closure, no recovery of H. nobilis stocks on reefs previously open to fishing was observed. Densities on reefs protected from fishing since the onset of the fishery in the mid 1980s remained about four times higher than on fished reefs. Based on density estimates and geographic information system data on the habitat area of each reef, we calculated that the virgin biomass (in the main fished area between 12 • and 19 • S) was about 5500 t and is now about 2500 t. The reduction is on the same order of magnitude as the total amount fished until 1999 (approximately 2500 t). The DNA analysis of repeated samples on three locations indicated high recapture rates of fingerprinted and released individuals of H. nobilis. Fitting growth curves with Francis's growth function indicated that medium-sized individuals (1 kg) grew 35-533 g /year, whereas large animals (2.5 kg) consistently shrank. Small animals (<500 g) were rarely observed. In combination, these data indicate that production of H. nobilis stocks is very low, presumably with low mortality, low recruitment, and slow individual growth rates. Consistent with anecdotal evidence, recovery of H. nobilis stocks on the GBR may take several decades, and we suggest a highly conservative management plan to protect both the stocks and the ecosystem.Resumen: Los holotúreos explotados comercialmente tiene importantes funciones en el reciclaje de nutrientes, lo que incrementa la productividad béntica en ecosistemas de arrecifes de coral. Por tanto, la pesquería de estos animales puede reducir la productividad total de los arrecifes coralinos afectados. Para investigar el potencial de recuperación de reservas sobreexplotadas de Holothuria nobilis en la Gran Barrera Arrecifal (GBA), 1) realizamos muestreos en 23 arrecifes después del cierre de la pesquería, 2) modelamos la biomassa virgen total y la comparamos con la captura total y 3) estimamos tasas de crecimiento individual con una técnica de impresiones de ADN. Dos años después del cierre de la pesquería, no se observó la recuperación de 1396 No Recovery in Overfished Holothurians Uthicke et al. existencias de H. nobilis en los arrecifes previamente abiertos a la pesca. Las densidades en arrecifes protegidos desde el comienzo de la pesquería a mediados de la década de 1980 permanecieron casi 4 veces más altas que en los arrecifes explotados. Con base en estimaciones de densidad e información de SIG sobre ...

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Abstract. Small-scale and artisanal fisheries for sharks exist in most inshore, tropical regions of the world. Although often important in terms of food security, their low value and inherent complexity provides an imposing hurdle to sustainable management. An observer survey of a small-scale commercial gill-net fishery operating within the Great Barrier Reef World Heritage area revealed at least 38 species of elasmobranch were present in the catch. Of the total elasmobranch catch, 95% was 25 species of Carcharhiniformes from the families Carcharhinidae, Hemigaleidae and Sphyrnidae. Individual species were captured in a variety of ways by the fishery, often with strongly biased sex ratios and in a variety of life stages (e.g. neonates, juveniles, adult). Despite this, the main carcharhiniform taxa captured could be qualitatively categorised into four groups based on similar catch characteristics, body size and similarities in life history: small coastal (,1000 mm); medium coastal (1000-2000 mm); large coastal/semi-pelagic (.2000 mm); and hammerheads. Such groupings can potentially be useful for simplifying management of complex multispecies fisheries. The idiosyncrasies of elasmobranch populations and how fisheries interact with them provide a challenge for management but, if properly understood, potentially offer underutilised options for designing management strategies.

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