The value of long-term, community-based monitoring of marine turtle nesting: a study in the Lamu archipelago, Kenya. Issue 1 (1st August 2017)

• Record Type: Journal Article
• Authors: Olendo, Mike I.; Okemwa, Gladys M.; Munga, Cosmas N.; Mulupi, Lilian K.; Mwasi, Lily D.; Mohamed, Hassan B.; Sibanda, Mxolisi; Ong'anda, Harrison O.
• Is Part Of: Oryx. Volume 53:Issue 1(2019)
• Page Start: 71
• Page End: 80
• Publication Date: 2017-08-01
• Subjects: Clutch size, -- community-based monitoring, -- green turtle, -- hatching success, -- hawksbill turtle, -- incubation duration, -- sea turtles, -- Western Indian Ocean; Wildlife conservation -- Periodicals; Nature conservation -- Periodicals; 639.9
• DOI: 10.1017/S0030605317000771
• Languages: English
• ISSNs: 0030-6053

Abstract

Abstract: Monitoring of nesting beaches is often the only feasible and low-cost approach for assessing sea turtle populations. We investigated spatio-temporal patterns of sea turtle nesting activity monitored over 17 successive years in the Lamu archipelago, Kenya. Community-based patrols were conducted on 26 stretches of beach clustered in five major locations. A total of 2, 021 nests were recorded: 1, 971 (97.5%) green turtle Chelonia mydas nests, 31 (1.5%) hawksbill Eretmochelys imbricata nests, 8 (0.4%) olive ridley Lepidochelys olivacea nests and 11 (0.5%) unidentified nests. Nesting occurred year-round, increasing during March–July, when 74% of nests were recorded. A stable trend in mean annual nesting densities was observed in all locations. Mean clutch sizes were 117.7 ± SE 1 eggs (range 20–189) for green turtles, 103 ± SE 6 eggs (range 37–150) for hawksbill turtles, and 103 ± SE 6 eggs (range 80–133) for olive ridley turtles. Curved carapace length for green turtles was 65–125 cm, and mean annual incubation duration was 55.5 ± SE 0.05 days. The mean incubation duration for green turtle nests differed significantly between months and seasons but not locations. The hatching success (pooled data) was 81.3% (n = 1, 841) and was higher for in situ nests (81.0 ± SE 1.5%) compared to relocated nests (77.8 ± SE 1.4%). The results highlight the important contribution of community-based monitoring in Kenya to sustaining the sea turtle populations of the Western Indian Ocean region.