Conservation status of crocodiles in Ghana and Coˆ te-d’Ivoire, West Africa M atthew H. Shirley,William O duro and H ilaire Y aokokore B eibro Abstract The population and conservation status of croc- African dwarf crocodile Osteolaemus tetraspis. A rich cul- odiles throughout West and Central Africa is poorly tural history has included both worship and overexploi- known and the IUCN Crocodile Specialist Group’s highest tation (Moiser & Barber, 1994; Kpera, 2003; Toonen, 2003) priority recommendations are country status surveys and but there is an almost complete deficit of knowledge re- examination of potential threats. This study presents garding ecology and population status of crocodiles across survey data and a review of the conservation status of the region (Ross, 1998). the Nile crocodile Crocodylus niloticus, slender-snouted Although the Nile crocodile is one of the most widely crocodile Mecistops cataphractus and African dwarf croc- studied crocodilians it has been little studied in West and odile Osteolaemus tetraspis at 67 sites throughout Ghana Central Africa (Pooley, 1980; Ross, 1998). Most of the and Coˆte d’Ivoire. No crocodiles were sighted in 31.5% of limited information available consists only of presence/ surveys but, where encountered, densities averaged 0.90 absence information (Wilson, 1978; Pooley, 1980; Kofron, crocodiles sighted km-1. The most frequently encountered 1992; Behra, 1993, 1994; Moiser & Barber, 1994; Dore, 1996; crocodile was C. niloticus (94% of sightings) with popula- Even, 1996; Akani et al., 1998; de Smet, 1999; Luiselli et al., tion structure highly biased to individuals , 1 year of age 2000; Shine et al., 2001; Kpera, 2003). Recent debate on the (41.4%). Only 14 M. cataphractus were observed. Local taxonomic status of this crocodile in West and Central informants report that crocodiles were more common Africa has highlighted the importance of understanding its 10–20 years ago than at present. There is now little commer- population status (Schmitz et al., 2003; Hekkala, 2004). It is cial harvest, which includes limited use in the bushmeat categorized as Lower Risk/least concern on the IUCN Red and traditional medicine markets, because of the croco- List (IUCN, 2008) but all West African populations are in dile’s scarcity. Habitat encroachment and incidental by- CITES Appendix I (UNEP-WCMC, 2008). The IUCN catch in fishing devices appear to be the major threats. Crocodile Specialist Group noted that surveys through- Actions needed to improve the conservation status of out this region are the highest priority for Nile crocodile crocodile populations in both countries, and throughout conservation (Ross, 1998). the region, are discussed. The slender-snouted crocodile is regarded by the Croc- odile Specialist Group as the least known crocodilian (Ross, Keywords Bushmeat, Coˆte-d’Ivoire, crocodile, Crocodylus, 1998 fishery, Ghana, Mecistops, Osteolaemus. ). Until recently it was considered to be a true cro- codile, in the genus Crocodylus, but has now been placed in the monotypic genus Mecistops (McAliley et al., 2006). In Introduction certain parts of its range (Gabon and Republic of Congo) it may still be relatively common (Thorbjarnarson & Eaton, rocodilians are charismatic megafauna that act as 2004), although the most recent surveys in West Africa Ckeystone species and often serve as indicators in (Waitkuwait 1985a,b, 1989) suggested that populations are ecosystem monitoring and restoration programmes (Ross, seriously declining. The slender-snouted crocodile is cate- 1998; Mazzotti et al., 2007). They are widely viewed as flagship gorized as Data Deficient on the Red List (IUCN, 2008) but conservation species and have the potential to galvanize the Crocodile Specialist Group has expressed concern that efforts in wetlands conservation. Three species are native it may meet the criteria for Endangered (Ross, 1998), and all to West Africa: the Nile crocodile Crocodylus niloticus,the populations are on CITES Appendix I (UNEP-WCMC, slender-snouted crocodile Mecistops cataphractus, and the 2008). The highest priority action for this species is surveys of population status throughout its range to determine MATTHEW H. SHIRLEY (Corresponding author) Department of Wildlife its Red List status and establish conservation programmes Ecology & Conservation, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL 32611-0430, USA. E-mail [email protected] (Ross, 1998). WILLIAM ODURO Department of Wildlife & Range Management, College of The African dwarf crocodile is a poorly known species Agriculture and Natural Resources, Kwame Nkrumah University of Science ranging throughout the lowland forest zone of West and and Technology, Kumasi, Ghana. Central Africa and inhabits forest waterways, swamp HILAIRE YAOKOKORE BEIBRO Laboratoire de Zoologie et de Biologie forests and isolated savannah pools (Kofron & Steiner, Animale, UFR Biosciences, Universite´ de Cocody-Abidjan, Abidjan, Coˆte- 1994 1998 1999 d’Ivoire. ; Ross, ; Riley & Huchzermeyer, ). Like the Received 5 September 2007. Revision requested 30 November 2007. Nile crocodile, its taxonomic status is uncertain, with a Accepted 8 January 2008. second taxon, Osteoblepharon osbornii,describedforanimals ª 2009 Fauna & Flora International, Oryx, 43(1), 136–145 doi:10.1017/S0030605309001586 Printed in the United Kingdom Downloaded from https://www.cambridge.org/core. IP address: 170.106.34.90, on 02 Oct 2021 at 22:03:34, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605309001586 Crocodiles in Ghana and Coˆ te-d’Ivoire 137 from the western Congo basin (Thorbjarnarson & Eaton, night temperatures during the study were 26°C and 23°C, 2004). The dwarf crocodile is cateogrized as Vulnerable on respectively. Our surveys were conducted during the latter the Red List (IUCN, 2008) and all populations are on half of the normal wet season, although drought conditions CITES Appendix I (UNEP-WCMC, 2008). Range-wide characterized 2006 and crocodiles were still limited to areas status surveys and evaluation of the threat from the bush- of permanent water. meat trade are priority actions for this species (Ross, 1998). Surveys were planned systematically according to in- The objective of this study was to survey the distribu- formation from published records, anecdotal reports, and tion, population status and threats facing the slender- presumed suitable crocodile habitats. Significant effort was snouted and Nile crocodiles in Ghana and Coˆte-d’Ivoire, made to sample broadly within each country to obtain and to collect data opportunistically on the African dwarf information over a wide range of habitat types, land uses, crocodile. and protection status. Political instability prohibited us from surveying the northern half of Coˆte-d’Ivoire (Fig. 1). Study area Methods From 19 July to 27 November 2006 we surveyed the status, distribution and threats faced by crocodiles in Ghana and Initial surveys detected low crocodile densities and we Coˆte-d’Ivoire (Fig. 1). The southern portion of both therefore decided to spend less time at each site and sample countries is mostly Upper Guinea Forest, whereas the more sites (Thompson, 2004). Surveys were conducted northern portion is largely wooded savannah. In both from available water craft and on foot. Diurnal surveys countries the major wet season is in March–June, a short were utilized to detect basking crocodiles and plan noctur- dry season in August, and a second, reduced wet season nal survey routes. Nocturnal spotlight surveys are a stan- from September to mid November. There is a unimodal dard crocodilian survey method (Webb & Smith, 1987); rainfall regime in the northern savannah zone from May/ crocodiles were detected with LED headlamps or a 100,000/ June to November (Grubb, 1998). The average day and 200,000 candlepower flood/spotlight. Length of survey FIG. 1 Locations surveyed for crocodiles in Ghana and Coˆte d’Ivoire (large dots). Small dots represent cities. ª 2009 Fauna & Flora International, Oryx, 43(1), 136–145 Downloaded from https://www.cambridge.org/core. IP address: 170.106.34.90, on 02 Oct 2021 at 22:03:34, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0030605309001586 138 M. H. Shirley et al. routes was calculated using a global positioning system. ent and historical crocodile abundance, relative value of, or This survey method results in an index of relative encoun- preference for, crocodile products (consumption, traditional ter rate because on any given survey not all individuals medicinal and religion), and human-crocodile conflict. of a population are detectable (Bayliss, 1987; Hutton & Woolhouse, 1989; Thorbjarnarson et al., 2000). Survey sites were characterized as river, flood plain (i.e. Results river or stream in wooded savannah habitat that flooded into the surrounding plain), natural lakes, artificial dams, Seventy-one crocodile surveys were conducted at 46 dif- coastal lagoons, wetlands (e.g. swamp forest), and urban or ferent sites covering 726.4 km of crocodile habitat (Table 1): other artificial habitats. When spotted, crocodiles were 25 sites (n 5 46 surveys, 333.7 km) in Ghana and 21 sites approached to determine species and estimate total length (n 5 25 surveys, 402.2 km) in Coˆte-d’Ivoire. Over 57%of in the following size classes: hatchling, , 1.0 m, 1.1 . 3.5 m surveys (n 5 41, 440.3 km) were in riverine habitat yet only in 0.25 m increments, and EO (eyes only) for unapproach- 36.5%(n5 100) of crocodile sightings were in rivers. In able individuals. While it is impossible to assign EO contrast, 11% of surveys (n 5 8, 137.3 km) were coastal individuals to a species with complete confidence location, lagoons, yet 31%(n5 85) of crocodiles were sighted there behaviour, size and other sightings allow some to be pro- (Table 1). No crocodiles were observed in 31.5% of surveys, visionally assigned. Unless otherwise stated, all crocodile and , 5 crocodiles were observed in 71% of surveys 1 encounters (both counts and rates) are presented as the (median encounter rate 5 0.26 km- ).