BIOTROPICA 37(1): 136–144 2005 Impact of Commercial Hunting on Monkey Populations in the Ta¨ ı region, C ˆ ote d’Ivoire 1 Johannes Refisch Department of Biogeography, University of Bayreuth, 95440 Bayreuth, Germany Ta¨ ı Monkey Project, Centre Suisse de Recherches Scientifiques, B.P. 1303 Abidjan, Cˆ ote d’Ivoire and Inza Kon´ e Ta¨ ı Monkey Project, Centre Suisse de Recherches Scientifiques, B.P. 1303 Abidjan, Cˆ ote d’Ivoire Laboratory of Zoology, University of Cocody, 22 B.P. 582, Abidjan 22, Cˆ ote d’Ivoire ABSTRACT We studied the impact of hunting on monkey species in the Ta¨ ı National Park and adjacent forests in Cˆ ote d’Ivoire. The average wild meat consumption per capita per year was assessed from market surveys and interviews. We determined that the amount of primate wild meat being extracted in the Ta¨ ı National Park and surrounding forests was 249 t in 1999. Hunting pressure was the highest on the larger primate species such as red colobus, Procolobus badius, black and white colobus, Colobus polykomos, and the sooty mangabey, Cercocebus torquatus atys. Estimates of population densities were based on line transect surveys. The maximum annual production of each species was calculated using the Robinson and Redford model (1991) and assuming unhunted conditions. Comparing current harvest levels with the maximum sustainable yield suggests that harvest of red colobus monkeys (Procolobus badius) is sustainable, whereas current off-take of the black and white colobus (Colobus polykomos), the sooty mangabey (Cercocebus atys), diana monkeys (Cercopithecus diana), and Campbell’s monkeys (Cercopithecus campbelli) exceeds sustainability by up to three times. R ´ ESUM ´ E Nous avons ´ etudi´ e l’impact de la chasse sur les esp` eces de singes dans le Parc National de Ta¨ ı et ses principales forˆ ets p´ eriph´ eriques en Cˆ ote d’Ivoire. La consommation moyenne de viande de brousse par capita et par an a ´ et´ e estim´ ee ` a partir d’´ etudes de march´ es et d’interviews. Nous avons estim´ e la quantit´ e de viande de gibier d’origine simienne extraite du Parc National de Ta¨ ı en 1999 ` a 249 t. La pression de la chasse ´ etait plus forte sur les esp` eces de singes de plus grande taille telles que le colobe bai, Procolobus badius, le colobe noir et blanc, Colobus polykomos, et le cercoc` ebe enfum´ e, Cercocebus torquatus atys. Les estimations de densit´ e de populations ont ´ et´ e faites par la m´ ethode des transects. La production annuelle maximale de chaque esp` ece a ´ et´ e calcul´ ee en utilisant le mod` ele de Robinson et Redford (1991) en supposant des conditions sans chasse. La comparaison des pr´ el` evements avec la production maximale soutenable sugg` ere que le pr´ el` evement en cours des colobes bais (Procolobus badius) est soutenable alors que celui de colobes noirs et blancs (Colobus polykomos), des cercoc` ebes enfum´ es (Cercocebus torqatus atys), des cercopith` eques dianes (Cercopithecus diana) et des mones de Campbell (Cercopithecus campbelli) exc` ede le seuil de durabilit´ e de jusqu’` a trois fois. Key words: Cˆ ote d’Ivoire; population density; primates; sustainability; wild meat. “WILD MEAT” 2 IS AN IMPORTANT SOURCE OF PROTEIN IN MANY SUB- SAHARAN AFRICAN COUNTRIES (Asibey 1977, Martin 1983, Anadu et al. 1988, Chardonnet et al. 1995, Juste et al. 1995). People have hunted wildlife since they have inhabited tropical forests. However, recently hunting has become unsustainable (Geist 1988; Ludwig et al. 1993; Alvard 1994; Muchaal & Ngandjui 1999; Wilkie & Carpenter 1999; Peres 2000a,b). The present study was carried out to investigate whether hunting of primates in the Ta¨ ı National Park and adjacent forest, Cˆ ote d’Ivoire, is sustainable. In Cˆ ote d’Ivoire, hunting is prohibited throughout the country. Nevertheless, it is commonly practiced (Caspary & Momo 1998). Once wild meat has reached public markets and restaurants, its trade and consumption are tacitly tolerated, apparently to avoid social conflicts. A widespread wild meat trade has developed in the informal sector and represents an important component of household economies. Caspary and Momo (1998) estimated that in 1996 100,000 t of wild meat 1 Received 7 October 2003; revision accepted 5 July 2004. 2 Following the recommendation of Milner-Gulland et al. (2003) we use the term “wild meat” instead of “bush meat.” entered the markets in Cˆ ote d’Ivoire, contributing 1.4 percent to the gross domestic product. Access to the Ta¨ ı National Park is strictly regulated, but nevertheless its fauna are experiencing hunting pressure. Previous studies have documented that duikers and primates are the most affected taxa (Hoppe-Dominik 1996, 1997; Caspary et al. 2001), but the extent to which the current off-take rates by hunters exceed levels that would permit sustainability remains largely unexplored. Sustainability is achieved when the rate of harvest does not exceed that of production. Robinson and Redford (1991) described a model to provide an estimate of maximum harvest rate based on the estimates of population densities and rates of population increase. We assessed the impact of hunting by comparing the calculated maximal production rate with the current off-take rate. Estimations of the current harvest rate are based on market surveys and interviews carried out by Caspary et al. (2001). This is the only source available, and thus used for this study. Caspary et al. (2001) counted primates and other mammals entering markets and local restaurants in the Ta¨ ı region between April 1998 and March 1999. Estimates of primate densities were based on transect counts conducted from June 1997 to November 1998 and in January/February 2000. 136