Nesting and at-sea distribution of marine turtles in Angola, West Africa, 2000–2006: occurrence, threats and conservation implications

Abstract

The status of marine turtles in Angola, West Africa, is poorly known, and therefore during 2000–2006 a combination of both dedicated and opportunistic beach and at-sea turtle surveys were carried out, and interviews conducted with fishing communities and at markets. Green Chelonia mydas, olive ridley Lepidochelys olivacea, leatherback Dermochelys coriacea and loggerhead turtles Caretta caretta were recorded, and nesting of the first three species confirmed during September–March (peaking November–December). Green turtles nested mainly in the south, leatherback turtles in north and central Angola, and olive ridley turtle nesting was widespread. Olive ridley turtle nest density at Palmeirinhas averaged 32 nests km−1. At-sea surveys produced 298 turtle records, with peak occurrence during August. Significant anthropogenic-related mortality (including exploitation of meat and eggs and fishing bycatch) was recorded, in addition to natural predation and other threats. Maintenance of the long-term sustainability of these turtle populations should focus on the involvement of fishing communities and increasing awareness throughout Angola.

On the front line: integrated habitat mapping for olive ridley sea turtles in the southeast Atlantic

“…Advancement of ecosystem‐based fisheries management schemes that promote responsible and sustainable practice may also be a way forward for artisanal fisheries (Casale, ). The implementation of any measures must also consider the social and economic impact to the industry, particularly to subsistence artisanal fisheries (Weir et al ., ; Lewison et al ., ).…”

“…Olive ridleys elsewhere can be negatively impacted by coastal and offshore trawl (Pandav et al ., ; Gopi et al ., ), purse seine (Abreu‐Grobois & Plotkin, ; Amandè et al ., ) and longline fisheries (Work & Balazs, ; Polovina et al ., ; Carranza et al ., ). Turtles are also at a high risk of bycatch from small‐scale, artisanal fisheries near to nesting or foraging grounds (Parnell et al ., ; Peckham et al ., ; Weir et al ., ; Maxwell et al ., ); olive ridleys have shown flexible internesting behaviour involving extensive travelling distances (Hamel et al ., ), which may increase exposure to bycatch.…”

Surveys of the Angolan coast uncover the largest olive ridley sea turtle nesting population in the Atlantic and the largest non-arribada population globally

“…Threats to sea turtles in Angola include egg collection and the capture of turtles while they are nesting (Morais et al, 2004; Buza, 2005; Weir et al, 2007; Morais, 2008, 2011, 2012a, 2012b, 2013, 2014, 2015, 2016), capture in fishing gear, responsible for the deaths of thousands of sea turtles (Morais, 2017, 2018, 2019), and predation of nests and hatchlings by domestic animals from communities near the nesting beaches (Morais, 2015, 2016). Additionally, there is high natural predation of nests by black-backed jackals Canis mesomelas in southern Angola (Morais, 2013), and predation of adults by spotted hyaenas Crocuta crocuta in northern Angola (Morais, 2015).…”

“…The coast of Angola is considered to be the southernmost range for nesting sea turtles in the eastern Atlantic (Carr, 1957; Brongersma, 1982; Fretey, 2001). Studies and reports of sea turtles in Angola indicate the presence of five species: the olive ridley Lepidochelys olivacea , leatherback, green Chelonia mydas , hawksbill Eretmochelys imbricata and loggerhead Caretta caretta , of which only the first three species are known to nest in Angola (Bocage, 1895; Monard, 1937; Brongersma, 1961, 1982; Hughes et al, 1973; Huntley, 1974; Hughes, 1982b; Carr & Carr, 1983, 1991; Pires, 1985; Afonso, 1987, Fretey, 2001; Morais et al, 2004; Buza, 2005; CABGOC, 2006; Morais et al, 2006; Weir et al, 2007; Morais, 2008, 2009, 2011, 2012a, 2012b, 2013, 2014, 2015, 2016, 2017, 2018, 2019; Ferreira et al, 2009). Designing targeted conservation actions along this coastline requires an understanding of the spatial and temporal distribution of the sea turtle species nesting in the country.…”

Nesting Ecology of Lepidochelys olivacea in Lobito, Angola

“…Of the five species reported to occur in Angola’s coast in the past [ 31 , 32 ], only three (olive, green, and leatherback turtles) species are reported to occur and nest in Angola [ 33 ]. The known projects either have not made the information available or are too recent and, as such, have insufficient information to address at least local knowledge deficiencies, which are fundamental for defining long-term and regional conservation strategies [ 11 , 34 , 35 ].…”