The abundance of false killer whale, Pseudorca crassidens (Cetartiodactyla: Delphinidae) in coastal waters of Golfo Dulce and Osa Peninsula, Costa Rica

Introduction: False killer whale (Pseudorca crassidens) is a tropical and subtropical social species that live in groups with individuals of mixed ages and sex classes. False killer whales have been documented since the late 1990s in Southwestern Costa Rica. Objective: To estimate the abundance of false killer whales in Osa Peninsula waters. Methods: Cetacean surveys off the Osa Peninsula Waters (OPW), Costa Rica, yielded opportunistic encounters with false killer whales in Drake Bay and Caño Island (2001-2019) and observations during formal surveys in Golfo Dulce (2005-2015). Photo-identification data was analyzed using capture-mark-recapture models in the study area, through an open population (POPAN) framework, considering the effect of time on the parameters apparent survival and capture probability, producing an abundance estimate for a superpopulation in the entire study area. Results: False killer whale abundance in OPW is characterized by a small population size of no more than 100 individuals, complemented by a very low probability of encounter and a contrasting high apparent survival. Conclusions: This population estimate should be taken as conservative, however, the small population size of less than 100 individuals should be considered vulnerable, in contrast to the increasing anthropogenic impacts in the coastal seascape. We argue the potential occurrence of population units along the coastal seascape of the Pacific littoral and oceanic island-associated units at Isla del Coco.

Introducción: La falsa orca es una especie gregaria tropical y subtropical, que vive en grupos con individuos de diferentes clases de edad y sexo. La falsa orca ha sido documentada en el sur-oeste de Costa Rica desde finales de los 90s. Objetivo: Evaluar el uso de hábitat de la especie en términos de abundancia. Métodos: Observaciones en campo para cetáceos en aguas de la Península de Osa (APO), incluyen encuentros oportunísimos en Bahía de Drake y la Isla del Caño (2001-2019), así como observaciones directas de Pseudorca crassidens, durante muestreos formales en Golfo Dulce (2005-2015). Se analizaron datos sobre foto-identificación utilizando modelos de marcaje captura y recaptura, considerando un enfoque para población abierta (POPAN), el cual considera el efecto del tiempo en los parámetros demográficos: supervivencia aparente (ф) y probabilidad de captura (P), produciendo un estimado de abundancia que comprende toda la superpoblación en el área de estudio. Resultados: La abundancia de la falsa orca en APO se caracteriza por un tamaño poblacional pequeño, de menos de 100 individuos, que se complementa por una muy baja probabilidad de captura, en contraste con una supervivencia aparente alta. Conclusión: Este estimado debe tratarse como conservativo, no obstante, el pequeño número poblacional, de menos de 100 individuos debe considerarse como vulnerable, en contraste con el incremento del impacto antropogénico del paisaje marino costero. Se discute la posible presencia de unidades poblacionales en el paisaje costero del litoral Pacífico y de unidades oceánicas asociadas a la Isla del Coco.

Capture-mark-recapture analysis on the under-registration rate of mortality surveillance program in Jinan / 中华流行病学杂志

Objective To evaluate the under-registration rate related to mortality surveillance program in Jinan city,from 2013 to 2014,using the capture-mark-recapture method.Methods Under the stratified cluster random sampling method,samples were stratified,according to urban and rural areas.Two districts and three counties were chosen,with three towns/streets in each county/district and eight villages/communities in each township/street,randomly selected.With the participation of departments as civil affairs,public security,maternal/child institutions and community committees as well as individuals as village doctors and community leaders,a list of deaths from January 1,2013 to December 31,2014 was collected and compared to the National Mortality Surveillance System on the rates related to under-registration.Results A total of 2 903 records on deaths were collected from 2013 to 2014,while 3 113 deaths were reported in the surveillance system of the same period.3 772 (95％ CI:3 741-3 802) deaths were estimated by the capture-mark-recapture method.The two-year total under-registration rate was 17.46％.The under-registration rates in 2013 and 2014 appeared as 19.29％ and 15.57％ (x2 =8.92,P＜0.01),respectively,with the rates in urban and rural areas as 20.91％ and 11.93％ (x2 =47.35,P＜0.01).The rates on male and female were 17.87％ and 16.98％ (x2 =0.48,P＞0.05).The rates of ＜5 years old group and ≥5 years old group were 21.57％ and 17.45％ (x2 =0.03,P＞0.05) respectively.Conclusions Under-registration in the mortality surveillance was noticed in Jinan.The capture-mark-recapture method seemed useful for evaluating the under-registration rate in the mortality surveillance program.It is suggested that the survey on under-registration rate should be carried out on the regular base.The under-registration rate seemed useful in adjusting the mortality rate.

Capture-mark-recapture analysis on the under-registration rate of mortality surveillance program in Jinan / 中华流行病学杂志

Objective To evaluate the under-registration rate related to mortality surveillance program in Jinan city,from 2013 to 2014,using the capture-mark-recapture method.Methods Under the stratified cluster random sampling method,samples were stratified,according to urban and rural areas.Two districts and three counties were chosen,with three towns/streets in each county/district and eight villages/communities in each township/street,randomly selected.With the participation of departments as civil affairs,public security,maternal/child institutions and community committees as well as individuals as village doctors and community leaders,a list of deaths from January 1,2013 to December 31,2014 was collected and compared to the National Mortality Surveillance System on the rates related to under-registration.Results A total of 2 903 records on deaths were collected from 2013 to 2014,while 3 113 deaths were reported in the surveillance system of the same period.3 772 (95％ CI:3 741-3 802) deaths were estimated by the capture-mark-recapture method.The two-year total under-registration rate was 17.46％.The under-registration rates in 2013 and 2014 appeared as 19.29％ and 15.57％ (x2 =8.92,P＜0.01),respectively,with the rates in urban and rural areas as 20.91％ and 11.93％ (x2 =47.35,P＜0.01).The rates on male and female were 17.87％ and 16.98％ (x2 =0.48,P＞0.05).The rates of ＜5 years old group and ≥5 years old group were 21.57％ and 17.45％ (x2 =0.03,P＞0.05) respectively.Conclusions Under-registration in the mortality surveillance was noticed in Jinan.The capture-mark-recapture method seemed useful for evaluating the under-registration rate in the mortality surveillance program.It is suggested that the survey on under-registration rate should be carried out on the regular base.The under-registration rate seemed useful in adjusting the mortality rate.

Long-distance movement by a great fruit-eating bat, Artibeus lituratus (Olfers, 1818), in southeastern Brazil (Chiroptera, Phyllostomidae): evidence for migration in Neotropical bats? / Deslocamento de longa distância por um grande morcego frugívoro, Artibeus lituratus (Olfers, 1818), no sudeste do Brasil (Chiroptera, Phyllostomidae): evidência de migração de morcegos Neotropicais?

In Brazil, bat migrations have been inferred based on seasonal variations in bat abundances observed for several species, probably as a result of variations in temperature and food availability. However, direct evidence of individual medium to long distance (> 10 km) movements, based on marked specimens, is restricted to large frugivorous bats, genus Artibeus (Phyllostomidae). We report the longest bat movement recorded in Brazil, along 113 km in a straight line, difference in altitude of 738 m, from a mixed Araucaria forest in Curitiba, PR, to the Atlantic Forest, Alto Ribeira, SP, by a female Artibeus lituratus (Olfers, 1818), over a period of 14 months. This data is consistent with the occurrence of migratory movements in Neotropical bats, such as the ecologically flexible Artibeus spp., over relatively large areas, probably with short stopover foraging intervals. Implications for the conservation of these bats are clear, as their home ranges may be much larger than their foraging areas, encompassing more than one biome and overcoming political borders.

Migrações em morcegos brasileiros têm sido inferidas a partir de variações sazonais nas abundâncias regionais das populações, provavelmente condicionadas por flutuações na temperatura e na disponibilidade de alimento. No entanto, registros de deslocamentos individuais de média a longa distância, ultrapassando suas áreas domiciliares (> 10 km), comprovados através de marcação e recaptura, são restritos aos grandes morcegos frugívoros do gênero Artibeus (Phyllostomidae). Registramos, aqui, o maior deslocamento já publicado, de ca. 113 km em linha reta, entre localidades com diferença de altitude de 738 m, respectivamente em floresta mista de araucárias, região de Curitiba, PR, e em Mata Atlântica, Alto Ribeira, SP, realizado por uma fêmea de Artibeus lituratus (Olfers, 1818), em um intervalo máximo de 14 meses. Este dado é consistente com a ocorrência de movimentos migratórios em Artibeus spp. ao longo de áreas bastante extensas, provavelmente através de várias etapas de forrageio. As implicações para a conservação desses quirópteros são claras, uma vez que os animais desta espécie podem ter áreas de vida bem maiores que suas áreas domiciliares (de forrageio), abrangendo mais de um bioma e ultrapassando limites geopolíticos.

Photo-identification as a technique for recognition of individual fish: a test with the freshwater armored catfish Rineloricaria aequalicuspis Reis & Cardoso, 2001 (Siluriformes: Loricariidae)

Photo-identification allows individual recognition of animal species based on natural marks, being an alternative to other more stressful artificial tagging/marking techniques. An increasing number of studies with different animal groups has shown that photo-identification can successfully be used in several situations, but its feasibility to study freshwater fishes is yet to be explored. We demonstrate the potential use of photo-identification for intraspecific recognition of individuals in the stream-dwelling loricariid Rineloricaria aequalicuspis . We tested photo-identification in laboratory and field conditions based on the interindividual variability in abdominal bony plates. Our test yielded high correct matches in both laboratory (100%) and field conditions (> 97%), comparable to other reliable techniques and to studies that successfully used photo-identification in other animals. In field conditions, the number of correct matches did not differ statistically between computer-assisted and naked-eye identification. However, the average time expended to conclude computer-assisted photo evaluations was about half of the time expended to conclude naked-eye evaluations. This result may be exacerbated when using database with large number of images. Our results indicate that photo-identification can be a feasible alternative technique to study freshwater fish species, allowing for a wider use of mark-recapture in ecological and behavioral studies.

A foto-identificação permite o reconhecimento individual de espécies de animais baseando-se em marcas naturais, sendo uma alternativa a outras técnicas de marcação artificial mais estressantes comumente usadas. O número crescente de estudos que usam foto-identificação em diferentes grupos animais mostra que esta técnica pode ser utilizada com sucesso, mas a viabilidade em estudos com peixes de água doce ainda não foi avaliada. Nós demonstramos o uso potencial da foto-identificação para o reconhecimento individual de peixes com indivíduos do loricarídeo Rineloricaria aequalicuspis. Nós testamos foto-identificação em condições de laboratório e de campo com base na variabilidade inter-individual das placas ósseas abdominais. O teste resultou em elevada porcentagem de acerto nas comparações, tanto para a condição de laboratório (100%) quanto para a de campo (> 97%), o que é comparável com outras técnicas confiáveis e com outros estudos que empregaram foto-identificação com sucesso. No teste de campo, o número de acertos não diferiu estatisticamente entre auxílio de computador e olho nu. Entretanto, o tempo médio despendido para concluir as avaliações com o auxílio de computador foi cerca da metade do tempo despendido para as avaliações a olho nu. Esse resultado pode ser exacerbado em avaliações com um grande número de imagens. Nossos resultados indicam que a foto-identificação pode ser uma técnica alternativa viável para estudar peixes de água doce e possibilita um uso mais amplo da marcação e recaptura para estudos ecológicos e comportamentais.

Estructura poblacional de Polythore gigantea (Odonata: Polythoridae) en sistemas lóticos con diferentes estados de conservación en Antioquia, Colombia / Population structure of Polythore gigantea (Odonata: Polythoridae) in lotic systems with different conservation states in Antioquia-Colombia

The knowledge about population structure and dynamics of some neotropical species, especially those living in lotic systems is still barely studied. This study had the aim to assess if the conservation status of some lotic systems, is related to some demographic variables of P. gigantea, so this may be used as a model for ecological monitoring. For this, we evaluated the population structure of P. gigantea three times per month (almost one sampling event every eight days) in four streams of the state of Antioquia, Colombia, from March-June 2009. The specimens were collected using entomological nets along a transect of 200m in the littoral zone of each stream. The insects were marked on the wings and the population size was estimated with the mark-recapture method. Our results showed that the largest population size was recorded for the stream “La Catedral” with aprox 299 individuals, followed by the stream “La Doctora” with 218 individuals. Nevertheless, no significant differences in population size among the evaluated streams were found; and no statistical relationships were found between vegetation variables and the population size of P. gigantea. However, taking into account the limited dispersal capacity of P. gigantea, its survival in the studied streams was considered to be at risk, due to the continuous modification of large riparian forest areas, which cause the increase of forest patches, with different levels of interconnection, and hinder long-term permanence of populations.

Evaluar si el estado de conservación de algunos sistemas lóticos, se relaciona con algunas variables demográficas de P. gigantea puede ser un modelo útil para el monitoreo ecológico. Se evaluó la estructura poblacional de P. gigantea en cuatro sistemas lóticos del Departamento de Antioquia, Colombia. Para cada quebrada, se emplearon tres eventos mensuales, repartidos en un evento cada ocho días, es decir, un total de 12 eventos para los cuatro sistemas lóticos, de marzo - junio de 2009. La metodología empleada fue marcaje y recaptura a lo largo de un transecto de 200m en la zona litoral de cada quebrada. El mayor tamaño poblacional promedio estimado por medio de Jolly, fue para la quebrada La Catedral con 299.4 individuos, seguida de la quebrada la Doctora con 218.3 individuos; sin embargo, no se encontraron diferencias significativas en el tamaño poblacional entre quebradas. No se encontraron relaciones estadísticas entre algunas variables estructurales de la vegetación con el tamaño poblacional de la especie en las cuatro quebradas. No obstante, teniendo en cuenta la limitada capacidad de dispersión de P. gigantea, esta constituye una especie con alto riesgo supervivencia en las quebradas evaluadas, a causa de la permanente modificación de extensas áreas de bosque por parte de los habitantes, que ocasionan la formación de numerosos fragmentos boscosos con diferente grado de interconexión y dificultan la permanencia a largo plazo de las poblaciones.

Growth and population assessment of the queen conch Strombus gigas (Mesogastropoda: Strombidae) by capture mark-recapture sampling in a natural protected area of the Mexican Caribbean / Evaluación del crecimiento y población del caracol rosado Strombus gigas (Mesogastropoda: Strombidae) mediante muestreo de marcaje-recaptura en un área natural protegida del Caribe mexicano

The Inlet of Xel-Ha is used as a park for ecotourism, representing a sanctuary for the conservation of Pink Queen Conch. Increasing fishing pressure has led to the inclusion of the species in CITES. Most knowledge about the growth of the queen conch was generated through aquaculture, ocean enclosures or obtained using estimates derived from population dynamics. In this study we estimated the growth rate of juvenile S. gigas in a natural protected area by direct methods, during the period of April 2009 to January 2011. Data was obtained by capture-mark-recapture sampling. 1418 individuals were tagged and growth of 714 conchs was analyzed. Population size and density was estimated using Schnabel’s method. The average density was estimated at 0.1694 ± 0.0996ind. m-2, while the highest density was estimated for September 2010 (0.3074ind. m-2). The highest growth rate (0.27 ± 0.10mm day-1) was detected in juveniles with an initial size between 100-149mm, followed by conch <100mm, with an increase of 0.24 ± 0.05mm day-1. The growth rate decreased for individuals with an initial size between 150-199mm (0.18 ± 0.09mm day-1) and for organisms > 200mm (0.08 ± 0.07mm day-1). Variability in growth rate was high in conch 100-149mm and showed seasonal differences, with the highest growth rate in May 2010. Recruitment of juveniles was highest in October 2009 and February 2010. The population of Xel-Ha has grown in size and more large and juvenile conch could be found than in previous studies, indicating that Xel-ha park is working as a sanctuary for the conservation of the queen conch in Mexico’s Riviera Maya. The growth rate of juvenile conch in Xel-Ha is high and exhibits large variations in individuals, reflecting the natural conditions of foraging and aggregation. Seasonal differences in growth rate may be associated with water quality and availability of nutrients for primary production. We conclude that the direct method is useful for the assessment of growth in juvenile S. gigas and that growth in natural conditions may be higher than in aquaculture systems. This information may be applied to fishery management as well as rehabilitation programs and aquaculture.

La Ensenada de Xel-Ha es usada como parque para ecoturismo y representa un santuario para la conservación del caracol rosado. El incremento en la presión de la pesca ha llevado a la inclusión de esta especie en CITES. Mucho del conocimiento acerca del crecimiento del caracol rosado ha sido generado a través de la acuicultura, encierros oceánicos o usando estimaciones derivadas de las dinámicas poblacionales. En este estudio estimamos la tasa de crecimiento de Strombus gigas juvenil en un área natural protegida, por métodos directos durante el período de abril 2009 a enero 2011. Los datos fueron obtenidos por muestras de captura-marca-recaptura. Un total de 1 418 individuos fueron marcados y el crecimiento de 714 caracoles fue analizado. La talla de la población y la densidad relativa fue estimada usando el método de Schnabel. La densidad promedio relativa fue estimada en 0.1694±0.0996ind. m-2, mientras que la densidad más alta fue estimada para septiembre 2010 con 0.3074ind. m-2. La tasa de crecimiento más alta (0.27±0.10mm día-1) fue detectada en juveniles con una talla inicial entre 100-149mm, seguida por juveniles <100mm, con un incremento de 0.24±0.05mm día-1. La tasa de crecimiento disminuyó para individuos con una talla inicial entre 150-199mm (0.18±0.09mm día-1) y para organismos >200mm (0.08 ± 0.07mm día-1). La variabilidad en la tasas de crecimiento fue alta en individuos entre 100-149mm y mostró diferencias estacionales; con la tasa de crecimiento más alta en mayo 2010. El reclutamiento de juveniles más alto se dio en octubre 2009 y en febrero 2010. La población de Xel-Ha ha crecido en tamaño y se pudo encontrar más adultos y juveniles que en estudios anteriores, lo que demuestra que el Parque de Xel-Há está funcionando como un santuario para la conservación del caracol rosado del Caribe en la Riviera Maya de México. La tasa de crecimiento de juveniles en Xel-Ha es alta y presenta grandes variaciones en los individuos, lo ...

Reinfestation of Streblidae ectoparasites (Diptera) in Carollia perspicillata (Linnaeus, 1758) (Chiroptera) / Reinfestação de ectoparasitas Streblidae (Diptera) em Carollia perspicillata (Linnaeus, 1758) (Mammalia: Chiroptera)

The mark-recapture method allows analysis on the variation in the abundance of bat ectoparasites at consecutive captures. The objectives of this study were to compare the pattern of Streblidae parasitism between capture and recapture of C. perspicillata; ascertain whether the abundance of Streblidae varied with time after removal of ectoparasites at capture and analyze whether the intensity of parasitism remained the same in each individual at capture and recapture. Using bats netted in the State of Rio de Janeiro, 42 individuals of C. perspicillata parasitized by two Streblidae species, Trichobius joblingi Wenzel, 1966 and Strebla guajiro (Garcia & Casal, 1965), were selected. The pattern of parasitism observed at capture was similar at recapture. No relationship was observed between the capture-recapture time interval and the abundance of ectoparasites. There was no relationship between the abundances of ectoparasites at capture and recapture of each individual.

A utilização da técnica de marcação-recaptura de morcegos permite a análise da variação na abundância de ectoparasitas de morcegos em capturas consecutivas. Os objetivos deste trabalho foram comparar o padrão de parasitismo de Streblidae entre captura e recaptura de Carollia perspicillata; verificar se a abundância de Streblidae varia com o tempo após a remoção dos ectoparasitas na captura e analisar se a intensidade de parasitismo permanece similar em cada indivíduo na captura e recaptura. Por meio de coletas com redes de neblina, no Estado do Rio de Janeiro, foram encontrados 42 indivíduos de C. perspicillata parasitados por duas espécies de Streblidae, Trichobius joblingi Wenzel, 1966 e Strebla guajiro (Garcia & Casal, 1965). O padrão de parasitismo observado durante a captura foi semelhante na recaptura. Não foi observada relação do tempo entre a captura e recaptura com a abundância de ectoparasitas. Não houve relação entre a abundância de ectoparasitas na captura e recaptura de cada indivíduo.

Fine scale gene flow and individual movements among subpopulations of Centrolene prosoblepon (Anura: Centrolenidae)

Dispersal capabilities determine and maintain local gene flow, and this has implications for population persistence and/or recolonization following environmental perturbations (natural or anthropogenic), disease outbreaks, or other demographic collapses. To predict recolonization and understand dispersal capacity in a stream-breeding frog, we examined individual movement patterns and gene flow among four subpopulations of the Neotropical glassfrog, Centrolene prosoblepon, at a mid-elevation cloud forest site at El Copé, Panama. We measured male movement directly during a two year mark-recapture study, and indirectly with gene flow estimates from mitochondrial DNA sequences (mtDNA). Individuals of this species showed strong site fidelity: over two years, male frogs in all four headwater streams moved very little (mean = 2.33 m; mode = 0 m). Nine individuals changed streams within one or two years, moving 675-1,108 m. For those males moving more than 10 m, movement was biased upstream (p < 0.001). Using mtDNA ND1 gene sequences, we quantified gene flow within and among headwater streams at two spatial scales: among headwater streams within two adjacent watersheds (2.5 km2) and among streams within a longitudinal gradient covering 5.0 km2. We found high gene flow among headwater streams (phi(ST) = 0.007, p = 0.325) but gene flow was more limited across greater distances (phi(CT) = 0.322, p = 0.065), even within the same drainage network. Lowland populations of C. prosoblepon potentially act as an important source of colonists for upland populations in this watershed.

La capacidad de dispersión determina y mantiene el flujo genético local, y esto tiene implicaciones para la persistencia poblacional y/o la recolonización que sigue a perturbaciones ambientales. Examinamos patrones individuales de movimiento y flujo genético entre subpoblaciones de Centrolene prosoblepon (Anura: Centrolenidae) en un sitio de elevación media en El Copé, Panamá. Medimos directamente el movimiento de los machos durante un estudio de marcado-recaptura, e indirectamente con estimaciones de flujo genético a partir de secuencias de ADN mitocondrial (mtDNA). Los individuos mostraron fuerte fidelidad a su lugar: por más de dos años, las ranas macho de los cuatro arroyos al inicio del río se movieron muy poco (promedio = 2.33 m; moda = 0 m). Nueve individuos cambiaron de corriente de agua en uno o dos años, moviéndose 675-1 108 m. Usando la secuencia genética ND1 del ADN mitocondrial, medimos el flujo genético en dos escalas espaciales: entre arroyos que originan el río (2.5 km2) y entre arroyos con un gradiente longitudinal en 5.0 km2. Encontramos un flujo genético alto entre los arroyos al inicio del río (f = 0.007, p = 0.325 y otro más limitado en distancias mayores (f = 0.322, p = 0.065).