Publications by category
Journal articles
van de Geer CH, Broderick AC, Carter MID, Irei AA, Kiponda FK, Kiptum J, Wandiga JN, Omar M, Parazzi N, Sawyer-Kerr H, et al (2024). Two decades of community-based conservation yield valuable insights into marine turtle nesting ecology.
Oryx, 1-13.
Abstract:
Two decades of community-based conservation yield valuable insights into marine turtle nesting ecology
Abstract
. For the Western Indian Ocean region, there is a significant knowledge gap regarding marine turtle nesting on the continental coast of East Africa. Here we present results from a long-term (2000–2020) community-based monitoring programme in and around Watamu Marine National Park, Kenya, covering 30 km of coastline (c. 6% of the national total). Conservation actions effectively protected nesting turtles and resulted in a near-total cessation of illegal egg harvesting in Watamu Marine National Park. Collected data indicate this is an important marine turtle nesting index site in Kenya and the wider region. Green turtle Chelonia mydas nests were most common (95%), followed by olive ridley turtles Lepidochelys olivacea (4%), with occasional nests of hawksbill Eretmochelys imbricata and leatherback turtles Dermochelys coriacea. Clutches per season increased significantly over the 20-year monitoring period for green turtles (50%) and showed a positive trend for olive ridley turtles. Watamu remains an area at risk from human pressures such as coastal development. Clutch distribution along the Watamu Marine National Park beach has shifted over time, probably because of coastal development and disturbance. Illegal take of adults and eggs continues in areas north and south of the Watamu Marine National Park, possibly slowing rates of recovery. Clutches deemed at risk were moved to a safe location within the National Park, and hatching success was high. Continued conservation efforts, including wider engagement with stakeholders to reduce human pressures, are needed to ensure the perpetuation of this nesting site.
Abstract.
de Geer C, Bourjea J, Broderick A, Dalleau M, Fernandes R, Harris L, Inteca G, Kiponda F, Louro C, Mortimer J, et al (2022). Marine turtles of the African east coast: current knowledge and priorities for conservation and research. Endangered Species Research, 47, 297-331.
Frias-Torres S, van de Geer C (2015). Testing animal-assisted cleaning prior to transplantation in coral reef restoration.
PeerJ,
3, e1287-e1287.
Abstract:
Testing animal-assisted cleaning prior to transplantation in coral reef restoration
Rearing coral fragments in nurseries and subsequent transplantation onto a degraded reef is a common approach for coral reef restoration. However, if barnacles and other biofouling organisms are not removed prior to transplantation, fish will dislodge newly cemented corals when feeding on biofouling organisms. This behavior can lead to an increase in diver time due to the need to reattach the corals. Thus, cleaning nurseries to remove biofouling organisms such as algae and invertebrates is necessary prior to transplantation, and this cleaning constitutes a significant time investment in a restoration project. We tested a novel biomimicry technique of animal-assisted cleaning on nursery corals prior to transplantation at a coral reef restoration site in Seychelles, Indian Ocean. To determine whether animal-assisted cleaning was possible, preliminary visual underwater surveys were performed to quantify the fish community at the study site. Then, cleaning stations consisting of nursery ropes carrying corals and biofouling organisms, set at 0.3 m, 2 m, 4 m, 6 m and 8 m from the seabed, were placed at both the transplantation (treatment) site and the nursery (control) site. Remote GoPro video cameras recorded fish feeding at the nursery ropes without human disturbance. A reef fish assemblage of 32 species from 4 trophic levels (18.8% herbivores, 18.8% omnivores, 59.3% secondary consumers and 3.1% carnivores) consumed 95% of the barnacles on the coral nursery ropes placed 0.3 m above the seabed. Using this cleaning station, we reduced coral dislodgement from 16% to zero. This cleaning station technique could be included as a step prior to coral transplantation worldwide on the basis of location-specific fish assemblages and during the early nursery phase of sexually produced juvenile corals.
Abstract.
van de Geer C, Mills M, Adams VM, Pressey RL, McPhee D (2013). Impacts of the Moreton Bay Marine Park rezoning on commercial fishermen. Marine Policy, 39, 248-256.
Publications by year
2024
van de Geer CH, Broderick AC, Carter MID, Irei AA, Kiponda FK, Kiptum J, Wandiga JN, Omar M, Parazzi N, Sawyer-Kerr H, et al (2024). Two decades of community-based conservation yield valuable insights into marine turtle nesting ecology.
Oryx, 1-13.
Abstract:
Two decades of community-based conservation yield valuable insights into marine turtle nesting ecology
Abstract
. For the Western Indian Ocean region, there is a significant knowledge gap regarding marine turtle nesting on the continental coast of East Africa. Here we present results from a long-term (2000–2020) community-based monitoring programme in and around Watamu Marine National Park, Kenya, covering 30 km of coastline (c. 6% of the national total). Conservation actions effectively protected nesting turtles and resulted in a near-total cessation of illegal egg harvesting in Watamu Marine National Park. Collected data indicate this is an important marine turtle nesting index site in Kenya and the wider region. Green turtle Chelonia mydas nests were most common (95%), followed by olive ridley turtles Lepidochelys olivacea (4%), with occasional nests of hawksbill Eretmochelys imbricata and leatherback turtles Dermochelys coriacea. Clutches per season increased significantly over the 20-year monitoring period for green turtles (50%) and showed a positive trend for olive ridley turtles. Watamu remains an area at risk from human pressures such as coastal development. Clutch distribution along the Watamu Marine National Park beach has shifted over time, probably because of coastal development and disturbance. Illegal take of adults and eggs continues in areas north and south of the Watamu Marine National Park, possibly slowing rates of recovery. Clutches deemed at risk were moved to a safe location within the National Park, and hatching success was high. Continued conservation efforts, including wider engagement with stakeholders to reduce human pressures, are needed to ensure the perpetuation of this nesting site.
Abstract.
2022
de Geer C, Bourjea J, Broderick A, Dalleau M, Fernandes R, Harris L, Inteca G, Kiponda F, Louro C, Mortimer J, et al (2022). Marine turtles of the African east coast: current knowledge and priorities for conservation and research. Endangered Species Research, 47, 297-331.
2015
Frias-Torres S, van de Geer C (2015). Testing animal-assisted cleaning prior to transplantation in coral reef restoration.
PeerJ,
3, e1287-e1287.
Abstract:
Testing animal-assisted cleaning prior to transplantation in coral reef restoration
Rearing coral fragments in nurseries and subsequent transplantation onto a degraded reef is a common approach for coral reef restoration. However, if barnacles and other biofouling organisms are not removed prior to transplantation, fish will dislodge newly cemented corals when feeding on biofouling organisms. This behavior can lead to an increase in diver time due to the need to reattach the corals. Thus, cleaning nurseries to remove biofouling organisms such as algae and invertebrates is necessary prior to transplantation, and this cleaning constitutes a significant time investment in a restoration project. We tested a novel biomimicry technique of animal-assisted cleaning on nursery corals prior to transplantation at a coral reef restoration site in Seychelles, Indian Ocean. To determine whether animal-assisted cleaning was possible, preliminary visual underwater surveys were performed to quantify the fish community at the study site. Then, cleaning stations consisting of nursery ropes carrying corals and biofouling organisms, set at 0.3 m, 2 m, 4 m, 6 m and 8 m from the seabed, were placed at both the transplantation (treatment) site and the nursery (control) site. Remote GoPro video cameras recorded fish feeding at the nursery ropes without human disturbance. A reef fish assemblage of 32 species from 4 trophic levels (18.8% herbivores, 18.8% omnivores, 59.3% secondary consumers and 3.1% carnivores) consumed 95% of the barnacles on the coral nursery ropes placed 0.3 m above the seabed. Using this cleaning station, we reduced coral dislodgement from 16% to zero. This cleaning station technique could be included as a step prior to coral transplantation worldwide on the basis of location-specific fish assemblages and during the early nursery phase of sexually produced juvenile corals.
Abstract.
2013
van de Geer C, Mills M, Adams VM, Pressey RL, McPhee D (2013). Impacts of the Moreton Bay Marine Park rezoning on commercial fishermen. Marine Policy, 39, 248-256.