Prospección de concha perlífera Pteria sterna en Talara, noviembre 2000

Identifica los principales bancos naturales para conseguir información sobre las poblaciones, densidades y principales características biológicas del recurso concha perla o concha perlífera (Pteria sterna) frente a las costas de Talara, así como sus relaciones y variaciones con el ambiente marino y la actividad extractiva, con el fin de brindar asesoria técnica al Ministerio de Pesquería para el establecimiento de adecuadas medidas de ordenamiento pesquero.

El bivalvo concha perlífera, Pteria Sterna (Gould), en Talara, Perú. Abril 2007

Analiza los aspectos biológicos, bancos naturales, distribución , concentración, asi como las condiciones ambientales de la concha perlífera.

Características de la vida planctónica y colonización de los organismos betónicos epilíticos durante el fenómeno El Niño

Durante «El Niño» (EN) de 1982 - 1983 se realizaron 2 experimentos en la Bahía de Ancón, a fin de reconocer las principales características de la reco­lonización en la biocenosis de Semimytilus algosus (zona mediolitoral), utilizando áreas cuadradas denudadas de 0,0625 m2 ; y en la de Aulacomya ater (a 5 metros de profundidad), colocando prismas triangulares de 0,2 m2 de área junto a un pequeño banco de este mitílido. Se analizaron periódicamente los cambios en el número de especies, densidad, biomasa, diversidad y velocidad de crecimiento de los principales coloniza­ dores. Paralelamente se tomaron datos oceanográficos y muestras periódicas de zooplancton y fitoplancton. En medio año de colonización, las características estructurales y tróficas de las 2 comunidades en suce­ sión han seguido patrones distintos, pero con un evidente proceso de tropicalización en ambos casos. Las larvas planctónicas con mayor abundancia a lo largo de todo el año pertenecieron al braquiópodo Discinisca lamellosa, a cirrípedos, gasterópodos y pelecípodos. En los experimentos, los mejores colonizadores primarios resultaron : Viva costata y Semimytilus algosus, en los cuadrados ; Hydroides parvus e Hydroides norvegica, en los prismas. Los mecanismos de competencia fueron más importantes en los cuadrados, destacando la ejercida por especies foráneas de aguas cálidas ( Pollicipes elegans, Pomatoceros sp.). En los prismas destacan los mecanismos de predación y resalta también la colonización por especies de aguas cálidas (Pomatoceros sp., Pteria sterna ) y por especies tradicionalmente escasas en la bahía (Argopecten purpuratus).

Reproductive dynamics of Sterna hirundinacea Lesson, 1831 in Ilha dos Cardos, Santa Catarina, Brazil

In this work, we intend to describe the reproductive dynamics of Sterna hirundinacea in an island fromSouth Brazil.We studied the reproductive biology of this species in its natural environment and provide data on their growth, survival, and reproductive success in Ilha dosCardos, SantaCatarina, South Brazil. Samplingswere carried out daily on the island throughout the reproductive seasons of 2003, 2005, and 2006 and the different stages of development of the chicks were characterized according to age, length of the beak, and plumage characteristics.We provide a basic equation Lm = 167.91 (1 – e −0.062t−(−0.23)) to determine the approximate age of individuals using their body mass. The main cause of chick mortality on the island was natural (63.17% in 2003, 81.41% in 2005, and 79.96% in 2006), whereas predation contributed to mortality in a proportion of 38.83% in 2003, 18.59% in 2005, and 20.04% in 2006.The absence in the area of the chicks’ main predator, Kelp gull (Larus dominicanus), the large number of chicks that reached the final stages of development, and their reproductive success demonstrate that Ilha dos Cardos is an important breeding site for the species in southern Brazil.

Treball de camp a una colònia de xatrac comú (sterna hirundo) en Alemanya

Estudio elaborado a partir de una estancia en el Institut fur Vogelforschung. El objeto de la estancia fue participar en la campaña de campo en la colonia de Charrán común (Sterna hirundo) situada en Wilhelmshaven (Alemania), entre los meses de mayo y agosto de 2005. Esta participación se llevó a cabo bajo la dirección del Prof. Dr. Peter H. Becker y junto a su equipo. Se participó en la recogida rutinaria de datos de la colonia así como en distintas técnicas relacionadas con el presente proyecto, como el marcaje de pollos, su observación directa desde escondites y la recogida de distintas muestras biológicas. El objetivo principal era continuar con la obtención de datos para el trabajo de investigación sobre la influencia de la calidad y la condición parental en la manipulación adaptativa de la razón de sexos y la asignación por sexos. La obtención de datos se basa en la implantación de transponders en pollos, que permiten la identificación de cada charrán de por vida. La combinación de esta información con la observación directa de cebas hace de la colonia un lugar excepcional, lo que permite conocer los factores que influyen en las tendencias que existan. Sin embargo, el objetivo específico de la campaña se centraba en investigar la variabilidad individual de la respuesta inmune en los pollos de charrán en relación a un número de atributos de los propios pollos (sexo, tamaño, tasa de crecimiento, proteínas en plasma, hematocrito, carga parasitaria, carotenos en plasma, isótopos de las plumas), de los padres (fecha y tamaño de puesta, calidad parental) y de las condiciones de cría (orden de eclosión, densidad de la sub-colonia). Los resultados de estos datos obtenidos durante la campaña respaldan que existe una influencia de la condición nutricional y la calidad parental en la respuesta immune de los pollos, debida probablemente a un esfuerzo reproductivo diferencial.

Forster’s Tern Sterna forsteri, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Interior Least Tern Sterna Antillarum, 2011

Data sheet produced by the Iowa Department of Natural Resources is about different times of animals, insects, snakes, birds, fish, butterflies, etc. that can be found in Iowa.

Foraging ecology and parental behaviour in the common tern (Sterna hirundo)

One component of successful parenting is related to efficiency in foraging behaviour. The relationships among chick feeding, the size and type of food package, and length of parental foraging trips has not been well studied in seabirds. In addition, relatively few data have been collected on the activities of seabirds when foraging away from the nest site. The objectives of this study were: (1) to contrast productivity, feeding rate, and attendance patterns of individuals carrying a novel transmitter with a control group of birds; (2) to use radio-telemetry to assess the variability in foraging locations within and between individual male Common Terns; (3) to determine the seasonal variation in chick diet; (4) to determine for each transmittered bird, the relationships among the foraging patterns, parental behaviour, and seasonal reproductive success. The study took place over two years (1990-91) on a concrete breakwater 1 km offshore on Lake Erie near Port Colbome, Ontario. Ten pairs of terns in 1990 and 12 pairs in 1991 were radio-tracked by boat or car during the chick rearing stage. Concurrent behavioural observations documented the time each sex spent foraging or at the nest. The frequency and prey species composition of feeds to chicks were also recorded. The transmitters had negligible effects on the feeding frequency and brood attendance patterns of transmitter carrying birds. Peak nesting transmittered birds in 1990 and 1991 exhibited some inter-individual variability in foraging locations, however intraindividual variability was low. Birds foraged primarily to the west and northwest of the colony. Late nesters exhibited greater inter-individual variability, however intra-individual variability remained low for most birds. Neither group demonstrated sufficient variability to support the regular use of this colony as an "information centre". Individual transmittered birds had unique and predictable foraging patterns, and corresponding differences in feeding frequencies and brood attendance patterns, yet productivity was essentially equal between nests due to the impact and importance of stochastic events. Individuals that were recaptured in 1991 exhibited very similar foraging patterns to 1990, suggesting littie variability between years. Conservation of foraging patterns between years may have potential implications for mate choice decisions in future breeding seasons. Prey species delivered to chicks differed between morning and evening for peak and late nesters in 1990, but not 1991. Peak nesters in 1990 fed significantiy more Rainbow Smelt fOsmerus mordM) than Emerald Shiner (Notropis atherinoidesV this trend was reversed for late nesters who also fed large numbers of unidentified larval fish. No significant differences were found in 1991. Seasonal changes in prey species delivered to chicks is believed to be attributable to the temperature tolerances of the smelt and shiners, and the presence of large schools of larval fish during the late nesting season.

Feeding rates, parental investment, and brood reduction in Caspian terns (Sterna caspia)

Fresh egg-weights and feeding rates to chicks were related to chick survival as one means of quantifying apportionment of parental investment wi thin broods of Caspian Terns (SterDI casRla) at a colony in Georgian Bay. Lake Huron, during 1978 and 1979. Ftrst-laid eggs from 2-egg clutches were Significantly heavier and usually hatched one to three days earlier than second-laid eggs in both years of the study. In both years, first-hatched chicks were larger and generally better fed than second-hatched siblings. The disparity between feedIng rates of first- and second-hatched ehicks was greater in 1979. Brood feeding I rates correlated positively with the percentage of food fed to the least-fed sibUng through the period of B-chick ages zero to 10 days in 1978. I suggest that after this age period, parental control over whlcb cbick was fed diminished. In 1978, 10 of 16 secondhatched chicks were fed more than their older siblings during their first 5 days. 'lb.is is interpreted as a parental response to reduce the competitive advantage of the larger first-hatched chicks. Most chick losses were apparently caused by starvation or preda. tion. In 1979, seeorvl-hatched chick disappearance (due to predation) was -related to low feeding rates, whereas first-hatched chick disappearance was related to low fresh egg-weights.. First-hatched chicks survived better than second-hatched chicks both years, and more pairs fledged two chicks in 1978. Maximum estimated feeding rates at the nest and fledging ages suggested that food was more avatlable in 1978 than in 1979. In 1979, second eggs apparently functioned as "insurance" eggs. When the first-laid egg falled to hatch, or the first-hatched chick died, the second-hatched chick was often successfully fledged. When first-hatched chicks survived, the second-hatched chick usually starved or was preyed upon, reducing the brood to one chick. Parental investment patterns favored first-hatched chicks. Brood reduction, when employed, discouraged total nest failure, however, under appropriate conditions, brood reduction was avoided and full broods (or two chicks) were fledged.

Genetic variability in Larus argentatus and Sterna hirundo

Blood serum and egg-white protein samples from individuals representing seven colonies of Larusargentatus, and four colonies of Sterna hirundo were electrophoretically analysed to determine levels of genetic variability and to assess the utility of polymorphic loci as genetic markers. Variability occurred at five co-dominant autosomal loci. S. hirundo protein polymorphism occurred at the Est-5 and the Oest-l loci, while nineteen loci were monomorphic. L. argentatus samples were monomorphic at seventeen loci and polymorphic at the Ldh-A and the Alb loci. Intergeneric differences existed at the Oalb and the Ldh-A loci. Although LDH-A100 from both species possessed identical electrophoretLc mobilities, the intergeneric differences were expressed as a difference in enzyme the'ITIlostabilities. Geographical distribution of alleles and genetic divergence estimates suggest ~ hirundo population panmixis,at least at the sampled locations. The h argentatus gene pool appears relatively heterogeneous with a discreet Atlantic Coast population and a Great Lakes demic population. These observed population structures may be maintained by the relative amount of gene flow occurring within and among populations. Mass ringing data coupled to reproductive success information and analysis of dispersal trends appear to validate this assumption. Similar results may be generated by either selection or both small organism and low locus sample sizes. To clarify these results and to detect the major factor(s) affecting the surveyed portions of the genome, larger sample sizes in conjunction with precise eco-demographic data are required.

Parental care in the common tern (Sterna Nirundo): sexual roles in a monogamous seabird

The parental behaviour of male and female Common Terns (Sterna hirundo) was documented throughout two breeding seasons at a colony near Port Colborne , Ontario. Thirteen and fourteen pairs of terns were chosen for intensive study in 1982 and 1983, respectively. The delivery of fish by males to their mates ("courtship feeding") occurred prior-to, during, and following the egg-laying period. Following the laying of the second egg, courtship feeding rates declined significantly. There was a significant, positive correlation bebween courtship feeding rates and subsequent chick feeding rates by males. The incubation rates of females were significantly higher than those of males, especially during the first ten days of incubation. Territorial attendance rates during the incubation stage were similar for males and females. During the chick stage, territorial attendance rates of females were significantly higher than those of males. The size of fish fed to chicks by males increased as the chicks grew older and chick feeding rates of males were approximately three times higher than female rates. Based on these quantitative differences in parental care activities, the cumulative parental time investment by the two sexes was very similar. However, the energetic investment by males was likely greater than that by females, since male parental contributions (e.g. courtship feeding and chick feeding) often entailed extensive foraging behaviour.

A study of selected factors influencing the reproductive performance of the common tern (Sterna hirundo) at Port Colborne, Ontario in 1973 and 1974

Several study areas were investigated at two Port Colborne terneries during the summers of 1973 and 1974 in an attempt to determine the influence of clutch size, time of clutch initiation, position in the colony, proximity to Ring-billed Gulls, vegetation and nesting substrate on the reproductive performance of the Common Tern. Hatching success and reproductive success (the number of chicks fledged per egg laid) were generally higher for 3-egg than 2-egg clutches but fledging (the number of chicks fledged per egg hatched) success was usually independant of clutch size. Hatching, fledging and reproductive success declined as a function of time of clutch initiation. Mean clutch sizes also generally declined as a function of time. Nests located in the center of the colony exhibited higher fledging success than those on the periphery. Rock-based clutches had a lower hatching success than clutches initiated on sand or dried vegetation. Reproductive performance did not appear to be related to proximity to Ring-billed Gulls or vegetation within the study area.

Foraging ecology and parental care of common terns (Sterna hirundo) nesting in Windermere Basin, Lake Ontario

The relationships among chick feeding, size and type of prey item, and foraging time away from the brood have not been well studied in seabirds. This study investigated spatial and temporal patterns of foraging and chick-provisioning among 23 radio-tagged male common terns nesting at Hamilton Harbour, Lake Ontario during 1991 and 1992. Telemetry data were collected concurrently with behavioural observations from an elevated blind. Terns fitted with transmitters did not differ from controls with respect to either brood attendance, patterns of chick mortality, species and size distributions of prey delivered to offspring, or chick-provisioning rates. There was a clear separation of parental roles: males were primarily responsible for feeding chicks while females allocated more time to brood attendance. The prey species most commonly delivered to chicks by adults were rainbow smelt (Osmerus mordax) and alewife (A/osa pseudoharengus), followed in importance by larval fish, emerald shiner (Notropis antherinoides), salmonids, and fathead minnows (Pimepha/es prome/as). The relative proportions of various fish speCies delivered to chicks by males differed over the course of each breeding season, and there was also much variability in species composition of prey between years. Sizes of prey delivered to chicks also differed between sampling periods. The modal size of fish brought to chicks during Peak 1991 was 1.5 bill lengths, while the majority of prey in Late 1991 were small larval fish. The reverse trend occurred in 1992 when small fish were delivered to chicks predominantly during the Peak nesting period. During periods when predominantly small fish were delivered to chicks, the foraging activity of radio-tagged males was concentrated within a two kilometer radius of the colony. The observed variation in prey composition and foraging locations during the study likely reflects temporal variation in the availability of prey in the vicinity of the colony. Males delivered fish to chicks at a constant rate, while females 4 increased their feeding frequency over the first six to ten brood days. The mean length of fish delivered to chicks by adults increased significantly with increasing chick age. As a group, within each nesting period, transmittered males either foraged predominantly in the same directional bearing (north during Peak 1991, south during Late 1992), or concentrated foraging activity in the immediate vicinity of the colony (Late 1991, Peak 1992). However, individual radio-tagged males exhibited unique and predictable foraging patterns, often favouring specific locations within these areas and differing in their secondary foraging patterns. Overall, the Lake Ontario shoreline between NCB Bay" (3.5 km south of colony) and the lift bridge canal (4 km north of colony) was the foraging area used most frequently by radiotagged males during the chick-rearing period. Foraging patterns of transmittered males at Windermere Basin are similar to patterns of peak-nesting common terns, but differ from those of late-nesters, at a nearby colony (Port Colborne, Lake Erie). Differences between the foraging patterns of late-nesting terns at these colonies likely reflect differences in annual patterns of fish availability between the two locations. No relationship was found between foraging proficiency of adults and survival of offspring. Stochastic factors, such as predation by black-crowned nightherons (Nycticorax nycticorax) and adverse weather conditions during the early stages of chick rearing, may be more important determinants of common tern breeding success than parental quality or fish availability.

Foraging Habitat and Chick Diets of Roseate Tern, Sterna dougallii, Breeding on Country Island, Nova Scotia

Breeding seabirds are threatened by human activities that affect nesting and foraging habitat. In Canada, one of the seabirds most at risk of extirpation is the Roseate Tern, Sterna dougallii. Although critical nesting habitat has been identified for the Roseate Tern in Canada, its foraging locations and the diet of its chicks are unknown. Therefore, our goal was to determine the foraging locations and diet of chicks of Roseate Tern breeding on Country Island, Nova Scotia, which is one of Canada's two main breeding colonies. In 2003 and 2004, we radio-tracked the Roseate Tern by plane to locate foraging areas and conducted feeding watches to determine the diet of chicks. Roseate Tern foraged approximately 7 km from the breeding colony over shallow water < 5 m deep. In both years, sand lance, Ammodytes spp., was the most common prey item delivered to chicks, followed by hake, Urophycis spp. Our results are consistent with previous work at colonies in the northeastern United States, suggesting that throughout its range, this species may be restricted in both habitat use and prey selection. The reliance on a specific habitat type and narrow range of prey species makes the Roseate Tern generally susceptible to habitat perturbations and reductions in the availability of prey.

Sterna, más que vela

[ES]El Sterna, velero de 26 metros capitaneado por el reconocido navegante oceánico y emprendedor Albert Bargués, es el único barco de nuestro país que ofrece viajes a vela por las grandes latitudes. A finales de octubre llega a Barcelona después de estar 5 meses para el Ártico. Albert y su equipo, junto con los grupos de viajeros que han embarcado en el Sterna este verano, han vivido experiencias irrepetibles y un acercamiento intenso a la naturaleza navegando por las Islas Svalbard, Isla del Hueso, Jan Mayen, costa este de Groenlandia …. La filosofía de Sterna se que “Todavía hay lugares en la tierra donde sólo se puede llegar desde el mar”. Con este principio, se navega por destinos poco habituales y remotos donde predomina el valor ambiental y el descubrimiento. Es un proyecto empresarial nacido en nuestro país y que, entre otras cosas, ha sido elegido por distintas entidades e iniciativas, como una de las empresas más innovadoras del momento invitándola a participar en diversos eventos (Salón Internacional del Turismo de Cataluña 2014 en Innovation Zone, Exposición Ayer, hoy y mañana Cataluña Emprende…). La voluntad de los fundadores de Sterna se aportar un valor ambiental y social a través de su actividad. Por eso el barco y sus navegaciones están disponibles para llevar a cabo proyectos de investigación y de divulgación del conocimiento. Entre las colaboraciones de Sterna de esta primera campaña en el ártico han salido una serie de publicaciones periódicas en la sección El Viajero de El País digital y un documental, en edición en estos momentos, “Latitud 80º” que ya ha sido presentado en foros internacionales del sector www.goroka.tv/portfolio/latitud-80-sterna/.