International Union for Conservation of Nature and Natural Resources

About: International Union for Conservation of Nature and Natural Resources is a nonprofit organization based out in Dhaka, Bangladesh. It is known for research contribution in the topics: Biodiversity & Population. The organization has 1317 authors who have published 1870 publications receiving 97588 citations.

Minimising bycatch of sensitive species groups in marine capture fisheries: lessons from tuna fisheries

Abstract: 11.1. INTRODUCTION 11.1.1. Ecological, Economic, and Social Issues Related to Fisheries Bycatch Bycatch in marine capture fisheries is the retained catch of nontargeted but commercially viable species (referred to as “incidental catch”) plus all discards (Food and Agriculture Organization of the United Nations [FAO] 2005).1 It is an increasingly prominent international issue, raising ecological concerns, as some bycatch species of cetaceans (whales, dolphins, and porpoises), seabirds, sea turtles, elasmobranchs (sharks, skates, and rays), and other fi sh species are particularly vulnerable to overexploitation and slow to recover from large population declines (FAO 1999a, 1999b, in press; Fowler et al. 2005; Gales 1998; Gilman et al. 2005, 2006a, 2006c, 2008; Lutz and Musick 1997). Bycatch can alter biodiversity and ecosystem functions by removing top predators and prey species at unsustainable levels (Myers et al. 2007). It also alters foraging behavior of species that learn to take advantage of discards. Economic effects of bycatch on fi sheries include loss of bait, reduced availability of baited hooks when they are occupied with unwanted bycatch species, and concomitant reduced catch of marketable species; the imposition of a range of restrictions, closed areas, embargos, and possible closures; allocation among fi sheries, where bycatch in one fi shery reduces target catch in another, and bycatch of juvenile and undersized individuals of a commercial species can adversely affect future catch levels (Brothers et al. 1999; Hall et al. 2000). Discarded bycatch raises a social issue over waste: From 1992 to 2001 an average of 7.3 million metric tons of fi sh were annually discarded, representing 8 percent of the world catch (FAO 2005). Prominent bycatch issues include dolphins and porpoises in purse seine fi sheries and driftnets; fi sh discards in shrimp trawl fi sheries; and seabird, sea turtle, marine mammal, and shark bycatch in longline, purse seine, gillnet, and trawl fi sheries (FAO 1999a, 1999b, 2005, in press; Hall et al. 2000). In commercial tuna fi sheries, the incidental bycatch of sensitive species groups (seabirds, sea turtles, marine mammals, and sharks) and bycatch of juvenile and undersized tunas are allocation and conservation issues. In addition to problematic bycatch, overexploitation and illegal, unreported, and unregulated (IUU) fi shing, which complicates bycatch management, are additional conservation issues facing the management of tuna fi sheries. This chapter employs examples of bycatch in commercial tuna fi sheries to describe (1) the range of options to reduce bycatch, (2) principles and approaches to successfully introduce effective bycatch reduction measures, and (3) initiatives taken by intergovernmental organizations, the fi shing industry, and retailers to address bycatch. Changes needed to improve the sustainability of tuna production are recommended.

African Rhino Specialist Group report/Rapport du Groupe Spécialiste des Rhinos d’Afrique

Abstract: A recent survey within the last known range of the West African black rhino Diceros bicornis longipes in northern Cameroon has failed to locate any sign of their continued presence although many signs of poaching activity were recorded. Drs Isabelle and Jean-Francois Lagrot spent four months in early 2006 patrolling 2500 km between Faro National Park and Bouba N’Djida National Park without success. Enquiry among 21 hunting guides also drew a blank. While Paul Bour of Association Symbiose will be in the field until the end of 2006 checking reports from the field, the outlook for this subspecies does not look good.

Defining ‘science-based targets’

Abstract: The term “science-based targets” has gained recent popularity. It is used to refer both to overall science-based targets (established through intergovernmental treaties), and to their disaggregation into specific science-based targets (determining contributions of individual actors). Biophysical achievability, measurability, and underpinning rationale are requirements for considering a target to be “science-based”.

Assessing the interaction between mountain forests and snow avalanches at Nevados de Chillán, Chile and its implications for ecosystem-based disaster risk reduction

Abstract: . Gravitational natural hazards such as snow avalanches, rockfalls, shallow landslides and volcanic activity represent a risk to mountain communities around the world. In particular, where documentary records about these processes are rare, decisions on risk management and land-use planning have to be based on a variety of other sources including vegetation, tree-ring data and natural hazard process models. We used a combination of these methods in order to evaluate dynamics of natural hazards with a focus on snow avalanches at Valle Las Trancas, in the Biobio region in Chile. Along this valley, natural hazards threaten not only the local human population, but also the numerous tourists attracted by outdoor recreational activities. Given the regional scarcity of documentary records, tree-ring methods were applied in order to reconstruct the local history of snow avalanches and debris flow events, which are the most important weather-related processes at respective tracks. A recent version of the model Rapid Mass MovementS (RAMMS), which includes influences of forest structure, was used to calculate different avalanche parameters such as runout distances and maximum pressures, taking into consideration the presence or absence of forest along the tracks as well as different modeled return periods. Our results show that local Nothofagus broadleaf forests contribute to a reduction of avalanche runout distances as well as impact pressure on present infrastructure, thus constituting a valuable ecosystem disaster risk reduction measure that can substitute or complement other traditional measures such as snow sheds.

Hawksbill turtles as significant predators on hard coral

Abstract: Hawksbill turtles (Eretmochelys imbricata), originally thought to be almost exclusively spongivorous (Meylan 1988), were later found to have a more diverse diet, feeding in the wild on sessile invertebrates such as sponges, zooanthids, soft corals, corallimorphs, ascidians and mobile invertebrates (Leon and Bjorndal 2002). We report here hawksbill predation on live tissue of a hard coral, the bubble coral Physogyra lichtensteinii (Milne Edwards and Haime 1851). This coral has a soft blistery coenosteum with large exsert septa, it is fleshy with vesicles expanded during the day, and it secretes a large amount of mucus, prefers deeper reef slopes and is usually at low densities though can be locally abundant. On the north shore of Aldabra atoll, P. lichtensteinii is the dominant coral between 20 and 35 m depth, at over 50% cover (Fig. 1a). In March 2008, noting a high frequency of fresh and old lesions on P. lichtensteinii (Fig. 1b, c), we observed an adult hawksbill, sex undetermined, feeding on P. lichtensteinii tissue (Fig. 1d, e). Feeding appeared targeted at the coral tissue rather than at boring infauna or epifauna, and healthy P. lichtensteinii tissue is normally continuous without either of these. We have observed and received reports of similar behaviour on the Amirantes islands (Seychelles), Phi Phi islands (Thailand), Isle St. Marie (Madagascar) and the Sudanese Red Sea, and a hawksbill gut from Cosmoledo atoll contained Physogyra or Plerogyra (another bubble coral) tissue (J. A. Mortimer, personal communication). At Isle St. Marie, predation was also observed on Plerogyra. This behaviour appears to be widespread in the Indian Ocean, and similar though less extensive reports have been made for the Pacific and Caribbean. On Aldabra, lesions on P. lichtensteinii were visually estimated to affect up to 5% of the species’ cover and apart from the turtle predation, no other causative factors (such as disease or other predators) were observed. Feeding on bubble corals may relate to nutrition from their fleshy tissue, low bite-resistance from their soft skeletons and/or their copious mucus production. It is unknown how general this phenomenon is, and it is interesting to speculate on its possible ecological role in pre-modern times when turtles were more abundant than today (Jackson 1997).