West African recreational fisheries, previously overlooked, are often assumed to be insignificant, yet they are increasingly present on social media given anglers' tendencies to document their experiences. It is important to catch the trend early on as recreational fisheries develop in order to support their sustainable development and to make the most of the alternative economic opportunities that they offer. Here, the recreational fisheries of 11 West African countries are assessed using tourist records from YouTube, blogs and other unconventional records. We introduce the concept of "Recreational-to-Commercial Ratio (RCR)", that is, the market-equivalent value per tonne of recreational fish injected to the economy, which is similar to "willingness to pay" for fish caught for recreation. Since the recreational fisheries of West African countries gained popularity in the last few years, catches increased and reached a total of 34,000 t annually, none of which was reported in official fisheries statistics. Recreational catches through a total annual revenue of US$152 million had an RCR of approximately 7, which means that developing recreational fisheries would increase the value of fish (whether caught or released) sevenfold. These findings could have major implications for the economy and conservation of fish stocks in West African countries.
The Bijagós archipelago (11 14 0 N-16 02 0 W) emerges from the shelf off Guinea-Bissau, not far from the mainland coast. It is the only active deltaic archipelago on the Atlantic coast of Africa. According to Limoges and Robillard (1991) it includes 88 islands and islets, some of which are mangrove islands flooded during spring tides, and some of which have several permanently emerged portions linked by intertidal mangroves. Twenty-one of the islands are permanently inhabited by communities of the Bijagós ethnic group. The islands are separated by a network of channels, and in general are surrounded by mangroves and extensive mud and sand flats, which together represent the most extensive intertidal area in Africa. Sediments originate mostly from the Corubal and Geba rivers and are deposited and moved around by a complex system of currents and
There is a paucity of information on the cetacean fauna of Guinea-Bissau in West Africa. We compiled records published in the literature and novel unpublished sighting data (2008–2014) to examine the occurrence and distribution of cetacean species. At least 10 species were verified to occur in Guinea-Bissau waters, of which eight were documented from a small number of sightings, whaling captures or skeletal remains. By far the most frequently recorded species were the common bottlenose dolphin (Tursiops truncatus) (N = 146) and the Atlantic humpback dolphin (Sousa teuszii) (N = 110). These two species were sympatric in distribution, both being found throughout coastal waters from the northern regions of Canal de Jeta and Rio Mansôa south to the Rio Cacine and around the Arquipélago dos Bijagós. However, differences were apparent in their finer-scale distribution and in the distance of sightings from shore, with bottlenose dolphin sightings generally occurring further from shore (and especially in the region of the Canal do Gêba) than Atlantic humpback dolphins. Sightings indicate that both species likely inhabit Guinea-Bissau waters throughout the year. Dedicated systematic cetacean survey work is urgently needed in coastal Bissau-Guinean waters in order to ascertain the abundance, spatio-temporal distribution, population structure and causes of mortality of bottlenose and Atlantic humpback dolphins, particularly given the Vulnerable conservation status of the latter species. Clarification of the status of cetaceans in offshore waters requires survey effort throughout the Guinea-Bissau EEZ.
structure d'une population par classes d'âges et de sexes est un élément important dans l'analyse des caractéristiques démographiques d'une espèce. Ses variations dans le temps et dans l'espace permettent de visualiser la chronologie des mouvements migratoires des différentes classes, ainsi qu• c leur distribution géographique respective. La possible répartition différentielle des sexes ou des âges risque d'avoir des consé quences sur l'équilibre démographique, si les facteurs de mortalité sont eux-rnêmes répartis de manière hétérogène à travers l'aire de distribution. Dans le cadre d'une étude sur l'hivernage du Canard siffleur, j'ai abordé cet aspect particulier de la biologie de l'espèce. Les deux populations visitant la France (Donker, 1959 ; Campre don, 1978) ont été analysées, en Camargue durant trois saisons, puis en Europe de l'ouest au cours de deux hivers.
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