Hawksbill (Eretmochelys imbricata) and Green Turtle (Chelonia mydas) Nesting and Beach Selection at Príncipe Island, West Africa

Hawksbills (Eretmochelys imbricata) and green turtles (Chelonia mydas) are the predominant nesting sea turtle species on the beaches of Príncipe Island in the Gulf of Guinea. The extent of nesting has been largely unknown, but such information is essential for management and conservation. Our study is the first island-wide nesting assessment. Results from the survey, conducted from 1 December 2009 to 18 January 2010 (during peak nesting season), show that the potential suitable nesting area (10 km) is scattered around the island’s 50 beaches. Sea turtles nested on 32 of the beaches (hawksbills, 20; green turtles, 28) and used 7.5 km of the suitable nesting habitat (hawksbills, 5.8 km; green turtles, 7.0 km). We estimated that 101 (95% CI = 86–118) clutches were deposited by 17-29 hawksbills and 1088 (95% CI = 999–1245) clutches were deposited by 166-429 green turtles on Príncipe from November 2009 to February 2010 (nesting season). Long-term green turtle nest count data collected from 2007/08 to 2015/16 suggest a positive trend. Analyses of clutch densities in relation to beach characteristics suggested that both species preferred areas where human presence is lower, which coincided with the most sheltered areas. These findings should be used to inform coastal planning and minimize impacts on nesting beaches, as Príncipe is currently targeted for tourism development. Overall, results highlight that Príncipe beaches are very important for the conservation of West African hawksbill and green turtle populations.info:eu-repo/semantics/publishedVersio

Despojos alimentares encontrados em abrigos de polvo comum (Octopus vulgaris) (Mollusca: Cephalopoda) do Faial (Açores) : dados preliminares.

VIII Expedição Científica do Departamento de Biologia – Ilha do Faial - 1993.The prey remains found around the dens of 6 octopus (Octopus vulgaris) were collected during the "Expedition Faial-93" (28 June to 3 July 1993) in "Reserva do Monte da Guia" by SCUBA diving (total of 4 dives). Based on this very preliminary work, the small crabs (Xantho spp.), bivalves (Limaria hians), and ormers (Haliotis tuberculata), seems to be the most important food items in the octopus feeding regime. Drill holes made by the octopus were observed on crab carapaces and chelipeds, but were not found on molluscan shells. The drill holes on the chelipeds or crabs are reported for the first time

Estimates of survival probabilities for oceanic-stage loggerhead sea turtles (Caretta caretta) in the North Atlantic

Estimates of instantaneous mortality rates (Z) and annual apparent survival probabilities (Φ) were generated from catch-curve analyses for oceanic-stage juvenile loggerheads (Caretta caretta) in the waters of the Azores. Two age distributions were analyzed: the “total sample” of 1600 loggerheads primarily captured by sighting and dipnetting from a variety of vessels in the Azores between 1984 and 1995 and the “tuna sample” of 733 loggerheads (a subset of the total sample) captured by sighting and dipnetting from vessels in the commercial tuna fleet in the Azores between 1990 and 1992. Because loggerhead sea turtles begin to emigrate from oceanic to neritic habitats at age 7, the best estimates of instantaneous mortality rate (0.094) and annual survival probability (0.911) not confounded with permanent emigration were generated for age classes 2 through 6. These estimates must be interpreted with caution because of the assumptions upon which catch-curve analyses are based. However, these are the first directly derived estimates of mortality and survival probabilities for oceanic-stage sea turtles. Estimation of survival probabilities was identified as “an immediate and critical requirement” in 2000 by the Turtle Expert Working Group of the U.S. National Marine Fisheries Service

A dieta do espadarte (Xiphias gladius) em águas Açorianas

Foram recolhidos um total de 132 estômagos de espadarte durante os anos de 1992/93 em indivíduos capturados em palangre derivante perto do arquipélago dos Açores. Os conteúdos foram completamente separados em componentes que incluíam: todos os estados de digestão de peixes e cefalópodes, desde peixes completos até fragmentos de músculo, ossos e otólitos e bicos de cefalópodes. Os peixes e os ossos maiores, que podem ser identificados, pertenciam todos a Capros aper, Lepidopus caudatus, Pagellus bogaraveo, mictofideos e, o peixe que servia de isco, Trachurus picturatus. Músculo das lulas Todarodes sagittatus, Pholidoteuthis boschmai e a lula que servia de isco Illex sp. também foi encontrada. 1249 otólitos e 120 bicos (inferiores) de cefalópodes foram identificados até ao género ou espécie. Encontrou-se uma média de 3.1 espécies e 18 animais representados em cada estômago. 98.4% dos estômagos apresentavam restos de peixes que contribuíam com 93.4% dos animais na dieta. Encontraram-se cefalópodes em 37.4% dos estômagos que contribuíram com 5.8% dos animais. Estimou-se que os pesos dos cefalópodes e peixes contribuíam respectivamente com 50.5% e 49.5% dos conteúdos estomacais. Os constituintes mais importantes da dieta, determinados por depleção de % peso estimado são Ommastrephes bartrami (24.4%), Lepidopus caudatus (17.4%), Pholi-doteuthis boschmai (15.9%), Capros aper (14.9%), Beryx spp. (5.4%), Micromesistius poutassou Onychoteuthis sp. (3.9%), Moroteuthis sp. (2.7%) e Pagellus bogoraveo (2.2%). Ao todo, há mais do que 18 espécies de peixe e 22 de cefalópodes na dieta. Apresentam-se as distribuições por tamanho de otólitos e bicos. Há espécies bentónicas e mesopelágicas de águas oceânicas, costeiras e profundas. Aparecem, na dieta, algumas espécies raras e não registadas para os Açores. As dietas não variam de acordo com a dimensão do espadarte amostrado ou entre sexos. Cálculos preliminares sobre a biomassa mínima consumida pelo espadarte dos Açores apontam para um número entre 7280 a 8680 t por ano, sendo aproximadamente metade peixe e metade cefalópodes.ABSTRACT: A total of 132 stomachs were collected in 1992-93 from swordfish caught on drifting longlines near the Azores. Contents were sorted completely into components which comprised all stages of digested fish and cephalopods from complete fish to fragments of muscle, bones, otoliths and beaks of cephalopods. Fish and larger bones which could be identified all belonged to Capros aper. Lepidopus caudatus, Pagellus bogaraveo, myctophids, and the fish used as bait, Trachurus picturatus. Flesh of the squids Todarodes sagittatus, Pholidoteuthis boschmai and the squid used as bait Illex sp. was also present. 1249 otoliths and 120 cephalopod lower beaks were identified to genus or species. There was a mean of 3.1 species and 18 animals represented in each stomach. Fish remains occurred in 98.4% of the stomachs and contributed 93.4% of animals in the diet. Cephalopod remains occurred in 37.4% and contributed 5.8% of animals. Estimates of the weights of fish and cephalopods show that cephalopods provide 50.5% and fish species 49.5% of the stomach contents. The most important constituents of the diet by decreasing % estimated weight are Ommastrephes bartrami (24.4%), Lepidopus caudatus (17.4%), Pholidoteuthis boschmai (15.9%), Capros aper (14.9%), Beryx spp. (5.4%), Micromesistius poutassou (4.3%), Onychoteuthis sp. (3.9%), Moroteuthis sp. (2.7%) and Pagellus bogaraveo (2.2%). In all, there are more than 18 species of fish and 22 species of cephalopod in the diet. Size distributions of otoliths and beaks are presented. The species include bottom and midwater forms from both oceanic and near island water and depths. A number of rare species of cephalopods and species not recorded for the Azores are in the diet. Diet does not differ according to the size of swordfish sampled or between female and male swordfish. Preliminary calculations were made on the minimum biomass eaten by the swordfish off the Azores as 7280 - 8680 t per year, approximately half fish and half cephalopods

Regime alimentar de tintureira (Prionace glauca L.) em águas Açorianas

Analisaram-se os conteúdos estomacais de 195 Prionace glauca, capturadas nos Açores entre Outubro de 1993 e Julho de 1994. Oitenta e três indivíduos possuíam estragos vazios. Apenas 23 estômagos continham animais inteiros ou semi-digeridos (excluindo o isco) pertencentes aos peixes Capros aper, Macrorhamphosus scolopax e Lepidopus caudatus e às lulas Histioteuthis bonnellii e Taonius pavo. Setenta e cinco otólitos de peixe e 207 bicos inferiores de cefalópodes foram identificados até ao género ou espécie. Considerando todos os fragmentos encontrados nos estômagos, incluindo otólitos, bicos de cefalópodes e cristalinos, foram encontrados 1411 peixes, 4 crustáceos e 261 cefalópodes. Aproximadamente 386 peixes estavam representados apenas por cristalinos. Foi encontrada uma média de 2.4 espécies (1.8 cefalópodes e 0.6 peixes) e 15.2 indivíduos por estômago. Restos de peixes foram encontrados em 83% dos estômagos analisados contribuindo em 84.5% dos animais da dieta. Restos de cefalópodes, foram encontrados em 75.7% dos estômagos e compunham 15.5% dos animais da dieta. As estimações dos pesos de peixes e cefalópodes, sugerem que os cefalópodes são, provavelmente, o grupo mais importantes na dieta de tintureira e, que são quase exclusivamente cefalópodes de flutuabilidade neutra meso- ou batipelágicos. Ocorrem pequenos cardumes de peixes epipelágicos e alguns peixes bentónicos maiores. No total, a dieta é composta por, pelo menos, 11 espécies de peixe e 37 de cefalópodes. É apresentada a distribuição de comprimentos de bicos e otólitos. Um número de espécies de cefalópodes raramente capturadas são, também, importantes para a dieta. Não foram encontradas diferenças na dieta relacionadas com o tamanho ou sexo de Prionace glauca. Comparações com a dieta de espadarte e de cachalote da mesma região sugerem claramente a existência de selecção na predação.ABSTRACT: Stomach contents of 195 Prionace glauca caught off the Azores from October 1993 to July 1994 were studied. Eighty three had empty stomachs. Only 23 contained whole or fleshy parts of animals (other than bait) and all belonged to the fish Capros aper, Macrorhamphosus scolopax and Lepidopus caudatus and the squids Histioteuthis bonnellii and Taonius pavo. Seventy five fish otoliths and 207 cephalopod lower beaks were identified to genus or species. Considering all fragments from the stomachs, including otoliths, cephalopod beaks and eye lenses, a minimum of 1411 fish, 4 crustaceans and 261 cephalopods were represented. Approximately 386 of the fish were represented by eye lenses alone. There was a mean of 2.4 species (1.8 cephalopods and 0.6 fish) and 15.2 animals represented in each stomach. Fish remains occurred in 83.0% of the stomachs and contributed 84.5% of animals to the diet. Cephalopod remains occurred in 75.7% and contributed 15.5% of animals. Estimates of the weights of fish and cephalopods suggest that cephalopods are probably the most important in the diet and these were almost entirely meso- or bathypelagic, neutrally buoyant cephalopods. Small epipelagic shoaling fish were present with a few much larger near-bottom fish. In all, there are at least 11 species of fish and at least 37 species of cephalopod in the diet. Size distributions of beaks and otoliths are presented. A number of rarely caught species of cephalopod are important in the diet. No difference was found in diet according to the size or between male and female Prionace glauca. Comparisons with swordfish and sperm whale diets from the same region clearly suggest selection in their predation

Impact of swordfish fisheries on sea turtles in the Azores.

The surface longline fishery around the Azores targets swordfish (Xiphias gladius). Bycatch from this fishery includes loggerhead sea turtles (Caretta caretta) and occasionally leatherback sea turtles (Dermochelys coriacea) that are either hooked or entangled in the lines. Hooks are generally set at depths of 15-50 m and baited with squid, mackerel, or sometimes with shark meat. The size classes of loggerhead sea turtles caught ranged from 41.3 to 65.4 cm curved carapace length and constitutes the largest size class of loggerheads occurring in the Azores. The impact on this size class affects the survival of the southeastern United States (SEUS) population of loggerheads because the loggerheads from the Azores are primarily from SEUS rookeries. For one commercial longline boat, we observed that the mean capture of turtles per 1000 hooks by month ranged between a minimum of 0.04 in May and a maximum of 0.79 in July with a weighted mean catch of 0.27. October and November also registered high catch rates. Of 60 turtles recorded, 54 were hooked in the mouth, 3 in the esophagus, 1 in the eye, 1 in the flipper, and one was undetermined. The turtles that were caught were physically strong, except one that was weak and another dead. Total capture of loggerhead sea turtles is estimated to be 4190 for the entire fleet fishing in the Exclusive Economic Zone of the Azores during the swordfish season (May to December) of 1998. We strongly recommend that observer programs be continued because capture rates may vary among years and among fishing boats

Compensatory growth in oceanic loggerhead sea turtles: response to a stochastic environment

Compensatory growth (CG, accelerated growth that may occur when an organism that has grown at a reduced rate as a result of suboptimal environmental conditions is exposed to better conditions) is considered an adaptation to variable en vironments. Although documented thoroughly under captive conditions, CG has rarely been studied in wild populations. In their first years of life, oceanic-stage loggerhead sea turtles (Caretta caretta) have relatively little control over their geographic position or movements and thus have an extremely stochastic lifestyle with great variation in food availability and temperature. This environmental variation results in variable growth rates. We evaluate somatic growth functions of oceanic-stage loggerheads from the eastern Atlantic based on skeletochronology that allowed us to assign age and cohort to each individual. We demonstrate CG in these turtles based on three different analytical approaches: changes in coefficients of variation in size-at-age, generalized additive model regression analyses of somatic growth, and linear regression of age-specific growth rates. As a result of CG, variation in size-at-age in these juvenile loggerheads is substantially reduced. Thus, size is a better predictor of age than expected based on variation in growth rates. CG decreases with age, apparently as loggerheads gain greater control over their movements. In addition, we have evaluated for the first time in wild sea turtles the time-dependent nature of somatic growth by distinguishing among age, year, and cohort effects using a mixed longitudinal sampling design with assigned-age individuals. Age and year had significant effects on growth rates, but there was no significant cohort effect. Our results address critical gaps in knowledge of the demog raphy of this endangered species.info:eu-repo/semantics/publishedVersio

New records and notes on little known shrimps (Crustacea, Decapoda) from Azorean waters.

Five species of shrimps (Crustacea, Decapoda) are recorded for the first time from the Azores: Funchalia villosa (Bouvier, 1905), Parapasiphae sucatifrons S.I. Smith, 1884 Heterocarpus ensifer A. Milne-Edwards, 1881, Heterocarpus laevigatus Bate, 1888 and Plesionika williamsi Forest, 1964. The variability of Plesionika gigliolii (Senna, 1903) and its relationship with P. sindoi (Rathbun, 1906) are discussed

Transatlantic developmental migrations of loggerhead sea turtles demonstrated by mtDNA sequence analysis

Molecular markers based on mitochondrial (mt) DNA control region se quences were used to test the hypothesis that juvenile loggerhead sea turtles (Caretta caretta) in pelagic habitats of the eastern Atlantic are derived from nesting populations in the western Atlantic. We compared mtDNA haplotypes from 131 pelagic juvenile turtles (79 from the Azores and 52 from Madeira) to mtDNA haplotypes observed in major nesting colonies of the Atlantic Ocean and Mediterranean Sea. A subset of 121 pelagic samples (92%) contained haplotypes that match mtDNA sequences observed in nesting colonies. Maximum likelihood analyses (UCON, SHADRACQ) estimate that 100% of these pelagic juveniles are from the nesting populations in the southeastern United States and adjacent Yucatan Peninsula, Mexico. Estimated contributions from nesting populations in south Florida (0.71, 0.72), northern Florida to North Carolina (0.19, 0.17), and Quintana Roo, Mexico (0.11, 0.10) are consistent with the relative size of these nesting aggregates. No contribution was detected from nesting colonies in the Mediterranean (Greece) or South Atlantic (Brazil), although samples sizes are insufficient to exclude these locations with finality. The link between west Atlantic nesting colonies and east Atlantic feeding grounds provides a more complete scientific basis for assessing the impact of subadult mortality in oceanic fisheries. Demographic models for loggerhead turtles in the western Atlantic can now be improved by incorporating growth and mortality data from juvenile turtles in pelagic habitats. These data demonstrate that the appropriate scale for loggerhead turtle conservation efforts is vastly larger than the current scale of management plans based on political boundaries.info:eu-repo/semantics/publishedVersio

Sea turtles : University of Florida – University of the Azores connection 1984 – present. A review

The loggerhead (Caretta caretta) is the most common sea turtle in the Azores. Since they do not nest in the area, a tagging program was started in the 1980’s to try to discover their origin. The result based on size distribution, suggested that they mainly are coming from beaches in SE United States. A collaboration between University of Florida and the University of the Azores began in 1984 in order to proceed with further research.info:eu-repo/semantics/publishedVersio