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Spatial Ecology of Inter- and Post-nesting Green Turtles (Chelonia mydas) on Bioko Island, Equatorial Guinea

<p>Effective conservation
strategies for sea turtles require knowledge of animal movements and protection
of biologically important habitats and life history stages. For breeding adult
sea turtles, understanding both their inshore and pelagic spatial patterns is
imperative to the successful protection of the species and the accurate
identification of their vulnerabilities. This study provides insight into the inter-nesting,
post-nesting, and foraging movements of green sea turtles (<i>Chelonia mydas</i>) that nest on Bioko Island, Equatorial Guinea, by
using satellite telemetry to track green turtles (n=12) during two nesting
seasons (2017-18, 2018-19), and as they migrated to foraging grounds after the
nesting season. These tracks were fit with a switching state space model to
characterize movements, and then analyzed in relation to environmental and
anthropogenic factors. Dive depth data was also used to determine utilization
patterns within the water column. The 12 tagged turtles migrated for an average
of 1064 km to two distinct foraging grounds, with 10 migrating west for an
average of 1115 km to the coastal waters of Ghana, and 2 migrating south for an
average of 1563 km to the coastal waters of Angola. Migrating turtles used both
direct, pelagic migration strategies, and biphasal, coastal strategies, which
included intermittent foraging throughout migrations. Dive depths varied
depending on behavior, with an average of 19.3 m during inter-nesting, 12.6 m
during migration and 8.5 m during foraging. Knowledge of inter-nesting habitat
use, migration patterns, and foraging ground locations will be critical for the
development of marine conservation management plans in the Gulf of Guinea and
aide in sea turtle conservation efforts throughout the area. Additionally, spatial
and dive depth data can inform zonal fishing regulators and provide information
needed for modifications to fishing practices and gear that is most likely to
reduce sea turtle bycatch. These data will provide a more complete
understanding of marine areas critical to sea turtle conservation and aide in
sustainable economic development in the Gulf of Guinea.</p><br>

  1. 10.25394/pgs.8023472.v1
Identiferoai:union.ndltd.org:purdue.edu/oai:figshare.com:article/8023472
Date10 June 2019
CreatorsEmily K Mettler (6620087)
Source SetsPurdue University
Detected LanguageEnglish
TypeText, Thesis
RightsCC BY 4.0
Relationhttps://figshare.com/articles/Spatial_Ecology_of_Inter-_and_Post-nesting_Green_Turtles_Chelonia_mydas_on_Bioko_Island_Equatorial_Guinea/8023472

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