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Abstract: Recent policy commitments aim to reduce biodiversity loss and integrate environmental concerns into Fisheries management. However, there are few operational indicators for reporting biodiversity trends and judging progress in [...]

Abstract: Understanding the relationships among life history traits, density dependence, and population dynamics is a central goal in ecology. It is also vital if we are to predict how populations [...]

Ghost sharks (subclass Holocephali) remain a largely data‐poor group of cartilaginous fishes. The general paucity of attention may partially be related to identification and unresolved taxonomic issues, occurrence in the deep oceans, and their low value and interest in fisheries (which some notable exceptions). Here, we synthesize and assess the extinction risk of all known extant ghost sharks (52 species) by applying the IUCN Red List of Threatened Species Categories and Criteria. Ghost sharks have a low proportion of threatened (8%) and Near Threatened (8%) species, with most species (69%) assessed as Least Concern. The group still exhibits some data deficiency (15%), and biological information is lacking for most species. Endemism is high, with 37% of species known from only one location or one country. Species richness was highest in the Northeast Atlantic, off the northwest coast of Africa (Morocco to Mauritania), the East China Sea, New Zealand and off the northwest coast of South America (Ecuador and Peru). Ghost sharks are predominately taken as by‐catch, but some targeted fishing and/or retention for the liver oil trade occurs. Species‐specific reporting, monitoring and management are required to assess population trends, and further investigation is needed on trade and use, particularly for higher risk species including the sicklefin chimaeras (genus Neoharriotta) and the American Elephantfish (Callorhynchus callorhynchus, Callorhinidae). [ABSTRACT FROM AUTHOR]

The Baraka's whipray (Maculabatis ambigua) is a major constituent of small‐scale fisheries catch in the south‐western Indian Ocean. Despite this, little is known of its life‐history or exploitation status. We provide the first estimates of crucial life‐history parameters and the maximum intrinsic population growth rate rmax, using specimens collected from small‐scale fisheries landings in Kenya, Zanzibar and Madagascar (with northern Madagascar representing a range extension for this species). We assess the relative risk of overexploitation by combining rmax with estimates of total Z, fishing F, and natural M mortality, and an estimate of the exploitation ratio E. The data indicate that Baraka's whipray is a medium‐sized, fast‐growing, early maturing species, with a relatively long lifespan. This results in a high rmax relative to many other elasmobranchs, which when combined with estimates of F suggests that the species is not at imminent risk of extinction. Yet, estimates of exploitation ratio E indicate likely overfishing for the species, with full recruitment to the fishery being post‐maturation and exploitation occurring across a broad range of age and size classes. Thus, Baraka's whipray is unlikely to be biologically sustainable in the face of current fisheries pressures. This paper makes an important contribution to filling the gap in available data and is a step towards developing evidence‐based fisheries management for this species. Further, it demonstrates a simple and widely applicable framework for assessment of data‐poor elasmobranch exploitation status and extinction risk. [ABSTRACT FROM AUTHOR]

The process of understanding the rapid global decline of sawfishes (Pristidae) has revealed great concern for their relatives, the wedgefishes (Rhinidae) and giant guitarfishes (Glaucostegidae), not least because all three families are targeted for their high‐value and internationally traded 'white' fins.The objective of this study was to assess the extinction risk of all 10 wedgefishes and six giant guitarfishes by applying the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria, and to summarize the latest understanding of their biogeography and habitat, life history, exploitation, use and trade, and population status. Three of the 10 wedgefish species had not been assessed previously for the IUCN Red List.Wedgefishes and giant guitarfishes have overtaken sawfishes as the most imperilled marine fish families globally, with all but one of the 16 species facing an extremely high risk of extinction through a combination of traits: limited biological productivity; presence in shallow waters overlapping with some of the most intense and increasing coastal fisheries in the world; and overexploitation in target and by‐catch fisheries, driven by the need for animal protein and food security in coastal communities and the trade in meat and high‐value fins.Two species with very restricted ranges, the clown wedgefish (Rhynchobatus cooki) of the Malay Archipelago and the false shark ray (Rhynchorhina mauritaniensis) of Mauritania, may be very close to extinction.Only the eyebrow wedgefish (Rhynchobatus palpebratus) is not assessed as Critically Endangered, with it occurring primarily in Australia where fishing pressure is low and some management measures are in place. Australia represents a 'lifeboat' for the three wedgefish and one giant guitarfish species occurring there.To conserve populations and permit recovery, a suite of measures will be required that will need to include species protection, spatial management, by‐catch mitigation, and harvest and international trade management, all of which will be dependent on effective enforcement. [ABSTRACT FROM AUTHOR]