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William E Feeney - One of the best experts on this subject based on the ideXlab platform.
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insights into the successful breeding of hawksbill sea turtles Eretmochelys imbricata from a long term captive breeding program
Global Ecology and Conservation, 2020Co-Authors: Ruth Maggeni, William E FeeneyAbstract:Abstract Sea turtle populations are declining and evidence-based methods for supporting their populations are required. Captive breeding and release programs can be effective, offering the opportunity to supplement nature populations; however, sea turtles require specific conditions to successfully breed. Here, we present insights gained from a 12 year Hawksbill sea turtle (Eretmochelys imbricata) captive breeding program that was conducted at the Underwater Observatory Marine Park, Eilat, Israel, between 1982 and 1997. As the first program of its kind for the Hawksbill sea turtle, insights were gained largely through trial-and-error and advice from experienced individuals. The key insight gained during this program was the critical importance of pre-breeding separation of the sexes; turtles did not breed prior to pre-breeding separation being implemented, but it became predictably regular once it was. Over the course of the program, 161 two-three year old hatchlings were introduced to the Red Sea, which was enabled largely as a result of pre-breeding separation being implemented.
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insights into the successful breeding of hawksbill sea turtles Eretmochelys imbricata from a long term captive breeding program
bioRxiv, 2020Co-Authors: Ruth Maggeni, William E FeeneyAbstract:Abstract Sea turtle populations are declining and evidence-based methods for supporting their populations are required. Captive breeding and release programs can be effective, offering the opportunity to supplement nature populations; however, sea turtles require specific conditions to successfully breed. Here, we present insights gained from a 16 year Hawksbill sea turtle (Eretmochelys imbricata) captive breeding program that was conducted at the Underwater Observatory Marine Park, Eilat, Israel, between 1982-1997. As the first program of its kind for the Hawksbill sea turtle, insights were gained largely through trial-and-error and word of mouth advice. The key insight gained during this program was the critical importance of pre-breeding separation of the sexes; turtles did not breed prior to pre-breeding separation being implemented, but it became predictably regular once it was. Over the course of the program, 161 two-three years old hatchlings were introduced to the Red Sea, which was enabled largely as a result of pre-breeding separation being implemented.
Ian Bell - One of the best experts on this subject based on the ideXlab platform.
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twenty eight years of decline nesting population demographics and trajectory of the north east queensland endangered hawksbill turtle Eretmochelys imbricata
Biological Conservation, 2020Co-Authors: Ian Bell, Kirstin Dobbs, J D Miller, Justin J Meager, Tomoharu Eguchi, C Madden A HofAbstract:Abstract Globally, hawksbill turtles (Eretmochelys imbricata) are listed as Critically Endangered, the cause of which is largely attributed to excessive historical take by the tortoiseshell industry. Yet few long-term data analyses describing population trend or survivorship exist. Here we analyse a long-term dataset for a globally significant western Pacific E. imbricata nesting population on Milman Island, northern Great Barrier Reef. Three demographic indicators were used: (1) number of egg clutches laid, (2) nester abundance and survival, and (3) the body-size distribution of nesters (curved carapace length, CCL). Models were developed for a time series from the 1990–91 to 2016–17 nesting season that included 21 years of sampling, with predicted trends evaluated against samples from the 2017–18 nesting season. The number of clutches laid and nester abundance rate of decline varied over the study period, but the decline was markedly similar with a 58 and 57% overall reduction, respectively. Annual survival rate was high (0.972, 95% CI = 0.965 to 0.977), but was not estimated separately for all years. Models predicted that the current rate of decline would lead to nesting extirpation by 2036 (95% CI: 2026–2058) and 2032–2037 (95% CI: from 2020 to increasing), for the models of nester abundance and number of eggs laid, respectively; and aligned with the observed values for the test dataset (2017–18 season). The rate of decline of E. imbricata nesting at Milman Island highlights the urgency to understand and mitigate risks faced by this endangered population and more broadly across the western Pacific.
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multinational genetic connectivity identified in western pacific hawksbill turtles Eretmochelys imbricata
Wildlife Research, 2018Co-Authors: Ian Bell, Michael P JensenAbstract:Context An understanding of the genetic stock structure of wide-ranging marine species is necessary for sound conservation management. Eretmochelys imbricata is Critically Endangered globally, but is among the least studied marine turtles. Reduced population sizes, its long-distance migratory nature between feeding and nesting habitats and poor understanding of its stock structure, biology and anthropogenic impact(s) pose challenges to developing effective conservation strategies for regional conspecifics. Aims Quantification of the population connectivity between specific feeding areas and regional nesting populations is needed for threat assessment and development of mitigation actions. Methods Here, we sequenced the mitochondrial DNA (mtDNA) of 91 immature and adult foraging E. imbricata individuals captured at the Howick Group of islands in the far-northern section of the Great Barrier Reef (nGBR), Queensland, Australia. We used a Bayesian mixed-stock analysis (MSA) approach to determine the contribution of nine regional genetically characterised breeding populations to this feeding aggregation. Key results The MSA estimated that a majority (83%; 95% CI = 70–92%) of feeding E. imbricata had originated from nesting beaches in the Bismarck–Solomon Sea region, whereas only 15% (95% CI = 6–25%) had originated from nGBR rookeries. International reproductive migrations were also corroborated by the return of 18 uniquely numbered titanium flipper tags that had been applied to E. imbricata found foraging in the Howick Group and had swum to rookeries within the Bismarck–Solomon Sea region. These 18 turtles represent 86% of all migration tag–recaptures from the Howick Group. Conclusions We postulate that recent increases in nesting populations within the Solomon Islands may be due to the high level of protection afforded to foraging turtles within the Great Barrier Reef. Implications An understanding of the connectivity between specific feeding areas and nesting populations is necessary to determine threats to animals over their entire life history and, therefore, allow the development of sound conservation management actions.
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algivory in hawksbill turtles Eretmochelys imbricata food selection within a foraging area on the northern great barrier reef
Marine Ecology, 2013Co-Authors: Ian BellAbstract:This paper describes the food selection of hawksbill turtles, Eretmochelys imbricata, using reefs of the Far Northern Section of the Great Barrier Reef Marine Park (nGBR) during 2006 and 2007. A total of 467 gastric lavage and 71 buccal cavity ingesta items were collected from 120 individual E. imbricata, comprising adult female and immature turtles of both sexes. Nineteen E. imbricata that were captured in 2006 were recaptured and sampled again in 2007. Within the total pooled buccal and lavage sample (n = 538), the occurrence of food items was dominated (72.7%) by only three algal taxonomic divisions: Rhodophyta (red algae; 53.7%, n = 289); Chlorophyta (green algae; 11.0%, n = 59) and algae from the division of Phaeophyceae (brown algae; 8.0%, n = 43). The remaining total (buccal and lavage) ingesta sample comprised sponges (10.4%, n = 56), soft corals and a wide variety of possibly nutritionally important invertebrate species (12.6%, n = 68), and a small percentage (5.4%, n = 22) of inorganic material. Generally, E. imbricata were considered to be primarily a sponge-feeding specialist and secondarily an omnivorous species; within coral reef habitats and in various parts of the world this is the case. However, this study has shown that E. imbricata found foraging on reefs of the nGBR are primarily algivorous and secondarily omnivorous. A feeding strategy that relies on a predominantly algal diet may infer important benefits to the species if the impacts of climate change and ocean acidification inhibit coral growth, while promoting algal density and distribution within the Great Barrier Reef ecosystem.
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high survivorship of an annually decreasing aggregation of hawksbill turtles Eretmochelys imbricata found foraging in the northern great barrier reef
Aquatic Conservation-marine and Freshwater Ecosystems, 2012Co-Authors: Ian Bell, Lin Schwarzkopf, Carryn ManicomAbstract:An 8-year study of the foraging abundance of an Eretmochelys imbricata aggregation, found on 13 reefs (Howick Group) within the northern section of the Great Barrier Reef Marine Park was undertaken. A CormackJollySeber method within program MARK was used to: (1) compare survival and recapture probabilities among age and sex classes of turtles; and (2) estimate survival and recapture rates for male and female adults and sub-adults from 665 capturemarkrecapture profiles of E. imbricata. Mean annual population density estimates were consistently greater for adult female E. imbricata (n=333.7; SD=135.6; R=221-581) than for adult males (n=32.4; SD=33.4; R=8-98), with both adult males and females displaying high survivorship rates (71.1%; 92.2%, respectively). This was also apparent in immature age-classes, with male and female turtles showing similarly high survivorship likelihoods (78.0%; 93.0%, respectively). Both sexes exhibited a similar overall trend with a peak population density being displayed in the first two years of the study, followed by a general decline in the female stock and stable male population. These are the only reliable long-term abundance time-series data for a population that includes all age-classes of E. imbricata in the western Pacific and provide good baseline data for the detection of possible climate change induced trends.
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somatic growth rates of hawksbill turtles Eretmochelys imbricata in a northern great barrier reef foraging area
Marine Ecology Progress Series, 2012Co-Authors: Ian Bell, David A PikeAbstract:An understanding of the rate at which long-lived species grow is essential for determining important life history parameters, including assessments of foraging habitat quality, the time taken to reach sexual maturity, and the age at which maturity is reached. The hawksbill sea turtle Eretmochelys imbricata is a Critically Endangered species that is typically associated with coral reefs throughout the tropical oceans. Little is known about its life history through most age-classes, especially in the western Pacific, one of the last strongholds for the species. We undertook annual surveys of a foraging population of hawksbill turtles on 13 reefs, within the far northern section of the Great Barrier Reef (GBR), from 1997 to 2008. We obtained growth rate data from 128 turtles that were recaptured once (n = 103), twice (n = 23), or 3 times (n = 2). The curved carapace length of recaptured turtles ranged from 61.3 to 91.4 cm (x= 79.8 ± 7.26 cm, mean ± SD). Recapture intervals spanned between 11 and 120 mo (mean: 59 mo; median: 72 mo). We show that mean annual growth rates did not differ between sexes and had a non-monotonic growth pattern, reaching peak growth for both sexes within the 65 to 70 cm curved carapace length size-class. Growth slowed thereafter at a linear rate, to negligible growth upon reaching an adult size of >80 cm. Hawksbill turtles grew faster in the southern GBR, compared to those found in the far north of the reef. Understanding spatial and temporal differences in growth rates, and thus age at maturity, is an important step towards resolving life history differences among sea turtle populations.
Ruth Maggeni - One of the best experts on this subject based on the ideXlab platform.
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insights into the successful breeding of hawksbill sea turtles Eretmochelys imbricata from a long term captive breeding program
Global Ecology and Conservation, 2020Co-Authors: Ruth Maggeni, William E FeeneyAbstract:Abstract Sea turtle populations are declining and evidence-based methods for supporting their populations are required. Captive breeding and release programs can be effective, offering the opportunity to supplement nature populations; however, sea turtles require specific conditions to successfully breed. Here, we present insights gained from a 12 year Hawksbill sea turtle (Eretmochelys imbricata) captive breeding program that was conducted at the Underwater Observatory Marine Park, Eilat, Israel, between 1982 and 1997. As the first program of its kind for the Hawksbill sea turtle, insights were gained largely through trial-and-error and advice from experienced individuals. The key insight gained during this program was the critical importance of pre-breeding separation of the sexes; turtles did not breed prior to pre-breeding separation being implemented, but it became predictably regular once it was. Over the course of the program, 161 two-three year old hatchlings were introduced to the Red Sea, which was enabled largely as a result of pre-breeding separation being implemented.
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insights into the successful breeding of hawksbill sea turtles Eretmochelys imbricata from a long term captive breeding program
bioRxiv, 2020Co-Authors: Ruth Maggeni, William E FeeneyAbstract:Abstract Sea turtle populations are declining and evidence-based methods for supporting their populations are required. Captive breeding and release programs can be effective, offering the opportunity to supplement nature populations; however, sea turtles require specific conditions to successfully breed. Here, we present insights gained from a 16 year Hawksbill sea turtle (Eretmochelys imbricata) captive breeding program that was conducted at the Underwater Observatory Marine Park, Eilat, Israel, between 1982-1997. As the first program of its kind for the Hawksbill sea turtle, insights were gained largely through trial-and-error and word of mouth advice. The key insight gained during this program was the critical importance of pre-breeding separation of the sexes; turtles did not breed prior to pre-breeding separation being implemented, but it became predictably regular once it was. Over the course of the program, 161 two-three years old hatchlings were introduced to the Red Sea, which was enabled largely as a result of pre-breeding separation being implemented.
M R Werneck - One of the best experts on this subject based on the ideXlab platform.
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infeccion por styphlotrema solitaria looss 1899 digenea styphlotrematidae en Eretmochelys imbricata linnaeus 1758 testudines chelonidae en brasil
Neotropical helminthology, 2021Co-Authors: M R Werneck, Reinaldo Jose Da SilvaAbstract:espanolThe aim of the present study is to report the occurrence of Styphlotrema solitaria Looss, 1899 infecting sea turtles of the species Eretmochelys imbricata Linnaeus, 1758 found in the North Coast of Sao Paulo State, Brazil. Only nine S. solitaria specimens were found in the hosts studied, with a mean intensity of infection of 4.5. Since 2002, 14 specimens of E. imbricata from this region were necropsied and the prevalence of S. solitaria was 14.2%. New variations on morphological data were presented for this digenetic species. This is the first occurrence of S. solitaria in sea turtles from Brazilian Coast, expanding the information on the helminth fauna of E. imbricata and the geographical distribution of S. solitaria. EnglishEl objetivo de esta investigacion es presentar la ocurrencia de Styphlotrema solitaria Looss, 1899 en las tortugas marinas de la especie Eretmochelys imbricata Linnaeus 1758 encontradas en el litoral Norte del Estado de Sao Paulo, Brasil. Apenas nueve especimenes fueron encontrados en los hospederos analizados correspondiendo a una intensidad media de 4,5. Desde el ano de 2002, 14 ejemplares de E. imbricata provenientes de esta misma region fueron necropsiados lo que corresponde a una prevalencia de 14,2 %. Nuevas variaciones y datos morfologicos se presentan para esta especie de digeneo. Esta es la primera ocurrencia de S. solitaria en las tortugas marinas encontradas en el litoral brasileno, ampliando asi la informacion sobre la helmintofauna de E. imbricata y distribucion geografica de S. solitaria.
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monticellius indicum mehra 1939 digenea spirorchiidae in a hawksbill turtle Eretmochelys imbricata linnaeus 1766 testudines cheloniidae from brazil
Comparative Parasitology, 2015Co-Authors: M R Werneck, Alessandro Trazi, Victor R Sousa, Bruno BergerAbstract:ABSTRACT: This note reports the first occurrence of Monticellius indicum Mehra, 1939, in the heart of the Hawksbill turtle, Eretmochelys imbricata Linnaeus, 1766, in the state of Espirito Santo, Brazil. This parasite has only previously been reported, to our knowledge, in Chelonia mydas from India, Brazil, and Costa Rica.
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the hawksbill sea turtle Eretmochelys imbricata linnaeus 1758 testudines cheloniidae as new host of hapalotrema postorchis rao 1976 digenea spirorchiidae
Comparative Parasitology, 2014Co-Authors: M R Werneck, Paula Baldassin, Felipe Dazeredo, Alessandro Trazi, Bruno BergerAbstract:This note describes the first occurrence of Hapalotrema postorchis Rao, 1976 in the heart of Hawksbill sea turtle Eretmochelys imbricata Linnaeus, 1758, from Espirito Santo State, Brazil. This parasite has previously been reported only in Chelonia mydas from India, Australia, the United States, Costa Rica, and Taiwan. The note constitutes the first documented occurrence of this parasite in sea turtles from the western South Atlantic Ocean.
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spirorchiids digenea spirorchiidae infecting a hawksbill sea turtle Eretmochelys imbricata linnaeus 1758 from brazil
Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, 2008Co-Authors: M R Werneck, Berenice Maria Gomes Gallo, Reinaldo Jose Da SilvaAbstract:The occurrence of Amphiorchis caborojoensis Fischthal & Acholonu 1976 and Carettacola stunkardi Martin & Bamberger 1952 in a young specimen of Hawksbill sea turtle Eretmochelys imbricata Linnaeus 1758 in Brazil was reported. Five A. caborojoensis trematodes were found in the small intestine (n=2) and liver (n=3), and two adult C. stunkardi specimens were collected from body wash. This is the first report of parasites of E. imbricata in Brazilian waters and Southwestern Atlantic Ocean and the second report of members of the Spirorchiidae family in that region. In addition, E. imbricata is a new host recorded for C. stunkardi.
Reinaldo Jose Da Silva - One of the best experts on this subject based on the ideXlab platform.
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infeccion por styphlotrema solitaria looss 1899 digenea styphlotrematidae en Eretmochelys imbricata linnaeus 1758 testudines chelonidae en brasil
Neotropical helminthology, 2021Co-Authors: M R Werneck, Reinaldo Jose Da SilvaAbstract:espanolThe aim of the present study is to report the occurrence of Styphlotrema solitaria Looss, 1899 infecting sea turtles of the species Eretmochelys imbricata Linnaeus, 1758 found in the North Coast of Sao Paulo State, Brazil. Only nine S. solitaria specimens were found in the hosts studied, with a mean intensity of infection of 4.5. Since 2002, 14 specimens of E. imbricata from this region were necropsied and the prevalence of S. solitaria was 14.2%. New variations on morphological data were presented for this digenetic species. This is the first occurrence of S. solitaria in sea turtles from Brazilian Coast, expanding the information on the helminth fauna of E. imbricata and the geographical distribution of S. solitaria. EnglishEl objetivo de esta investigacion es presentar la ocurrencia de Styphlotrema solitaria Looss, 1899 en las tortugas marinas de la especie Eretmochelys imbricata Linnaeus 1758 encontradas en el litoral Norte del Estado de Sao Paulo, Brasil. Apenas nueve especimenes fueron encontrados en los hospederos analizados correspondiendo a una intensidad media de 4,5. Desde el ano de 2002, 14 ejemplares de E. imbricata provenientes de esta misma region fueron necropsiados lo que corresponde a una prevalencia de 14,2 %. Nuevas variaciones y datos morfologicos se presentan para esta especie de digeneo. Esta es la primera ocurrencia de S. solitaria en las tortugas marinas encontradas en el litoral brasileno, ampliando asi la informacion sobre la helmintofauna de E. imbricata y distribucion geografica de S. solitaria.
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Helminth Parasites of the Juvenile Hawksbill Turtle Eretmochelys imbricata (Testudines: Cheloniidae) in Brazil
The Journal of parasitology, 2015Co-Authors: Eduardo H. S. M. Lima, T. T. Pires, Reinaldo Jose Da SilvaAbstract:The helminth fauna of 31 juvenile specimens of Eretmochelys imbricata from the Brazilian coast was examined. Seventeen individuals were infected with helminths (54.8%). The helminths found were: Diaschistorchis pandus, Cricocephalus albus, Metacetabulum invaginatum, Pronocephalus obliquus (Pronocephalidae), Cymatocarpus solearis (Brachycoeliidae), Styphlotrema solitaria (Styphlotrematidae), Carettacola stunkardi, Amphiorchis caborojoensis (Spirorchiidae), Orchidasma amphiorchis (Telorchiidae), and Anisakis nematode larvae. This report is the first analysis of parasite communities in this host.
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spirorchiids digenea spirorchiidae infecting a hawksbill sea turtle Eretmochelys imbricata linnaeus 1758 from brazil
Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, 2008Co-Authors: M R Werneck, Berenice Maria Gomes Gallo, Reinaldo Jose Da SilvaAbstract:The occurrence of Amphiorchis caborojoensis Fischthal & Acholonu 1976 and Carettacola stunkardi Martin & Bamberger 1952 in a young specimen of Hawksbill sea turtle Eretmochelys imbricata Linnaeus 1758 in Brazil was reported. Five A. caborojoensis trematodes were found in the small intestine (n=2) and liver (n=3), and two adult C. stunkardi specimens were collected from body wash. This is the first report of parasites of E. imbricata in Brazilian waters and Southwestern Atlantic Ocean and the second report of members of the Spirorchiidae family in that region. In addition, E. imbricata is a new host recorded for C. stunkardi.