Page 36 - Atlas Sea Birds Ver1

2.1.1 Population trends and conservation status of sea turtles off the
coast of Angola

Author: Michel Morais

Abstract:
Five species of sea turtle occur in Angola’s coastal waters: Leatherback Dermochelys coriacea, Green Chelonia mydas, Olive Ridley
Lepidochelys olivacea, Loggerhead Caretta caretta and Hawksbill Eretmochelys imbricata. The first three of these species breed regularly
to the north of the front between the Angola and Benguela currents. Between 2010 and 2021, numbers of female turtles nesting annually
in Angola were on average c. 850 for Leatherback, c. 90 for Green and c. 61,000 for Olive Ridley (the largest population of this species in
the Atlantic Ocean). In this period numbers of Leatherback and Olive Ridley turtles that nested decreased, whereas those of Green Turtle
were stable. There is just one record of Loggerhead Turtle nesting in Angola and none of Hawksbill Turtle. Large numbers of Green Turtles
feed seasonally at three localities between the Congo and Cunene rivers. North Angola may be an important nursery and feeding area
for Hawksbill Turtle.
Introduction:
Although there has been a single record of Green Turtle (Chelonia mydas) nesting, albeit without hatching success, at the mouth of the
Cunene River on the Namibian side of that river (Cunningham and van Rooyen 2020), the coast of Angola can still be considered as the
southernmost place in the east Atlantic where regular nesting of sea turtles takes place (Carr 1957, Brongersma 1982, Bernardo and
Plotkin 2007).
Comprehensive, recent surveys in south Angola (Morais 2013, 2015, 2017, 2021) suggest that Ponta Albina at the boundary between
the Angola and Namibe ecoregions, and the approximate location of the Angola/Benguela Current Front (Figure 1), is the southern
limit in the southeast Atlantic for regular nesting of sea turtles (Morais 2015, 2021, Morais and Tiwari 2022). This means that only about
1,210 km of the 1,650 km of coastline in Angola is used for nesting by sea turtles.
The incidence and success of nesting is not only influenced by the coastal biotype, but also by the physical variability of the marine and
coastal ecosystem. Cliffs adjacent to the sea and without a sandy beach in the north region and in a large part of that between Cuio and
Namibe are not suitable for nesting. By contrast, there is no regular nesting in the region just south of Ponta Albina, despite its extensive
sandy beaches (Morais 2013, 2015, 2017).
Five of the world’s seven species of sea turtle occur off Angola: namely Leatherback Dermochelys coriacea (Eschscholtz, 1829), Green
Chelonia mydas (Eschscholtz, 1829), Loggerhead Caretta caretta (Eschscholtz, 1829), Olive Ridley Lepidochelys olivacea (Eschscholtz,
1829) and Hawksbill Eretmochelys imbricata (Eschscholtz, 1829) (Bocage 1895, Brongersma 1961, 1982, Hughes et al. 1973, Huntley
1974, Hughes 1982, Carr and Carr 1983, 1991, Fretey 2001, Morais et al. 2004, 2006, Weir et al. 2007, Morais 2008, 2013, 2015, 2017,
2019, 2021, Ferreira et al. 2009). The first four of these turtles have nested in Angola (Morais 2015).
The main turtle nesting season on the coast of Angola regularly takes place between September and March, with that in the southern
region starting somewhat later than in the central-north part, although isolated nesting has been seen throughout the year at various
coastal localities (Carr and Carr 1991, Morais et al. 2004, Morais 2008, 2012b, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021,
Morais and Tiwari 2022). Nesting peaks occur between November and January (Morais 2015, Morais and Tiwari 2022).

Spatial distribution Green Turtle (Chelonia mydas)

Leatherback Turtle (Dermochelys coriacea) Green Turtles have nested in several coastal regions of
Angola (Hughes et al. 1973, Huntley 1974, Carr and Carr
For Leatherback Turtles, in Angola historical accounts re- 1991, Morais 2015, 2016, 2017, 2018), especially in Cabi-
ferred to their nesting between Cabinda (5.0447 S) and nda (5.0447 S and 5.7744 S) (Carr and Carr 1991,
Quicombo (11.2910 S) (Hughes et al. 1973, Huntley 1974, Morais 2008), Soyo (6.0877 S), Kissembo (7.7079 S)
Carr and Carr 1991, Morais et al. 2004, Morais 2008) and (Morais 2016, 2019), Luanda (9.0857 S) (Bocage 1895,
being abundant. Both adult and sub-adult animals were Carr and Carr 1991), Longa (10.2538 S) (Morais 2021),
observed along the coast (Carr and Carr 1991). However,
surveys carried out along the entire coast of Angola and
monitoring at localities undertaken by the Kitabanga Proj-
ect, which commenced in 2003, indicated that the south-
ernmost limit of nesting by Leatherbacks was the Bentiaba
region (14.1754 S), although Leatherbacks were reported
(but not confirmed) to be present in the vicinity of Baía das
Pipas (14.9179 S) farther south (Morais 2013, 2015, 2019,
Figure 2).
Aerial surveys indicated that the regions of Onzo
(9.2253 S), Palmeirinhas (9.0857 S), between Cabo Ledo
(10.7086 S) and Cabo das Três Pontas (11.3994 S),
Cabeça da Baleia (12.6142 S) and Egipto Praia (12.9728 S)
had the largest numbers of nesting females (Morais 2015, A Leatherback Turtle returning to the sea after nesting in the
Figures 1 and 2). Palmeirinhas region (photo Michel Morais, Projecto Kitabanga)

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