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Heterogeneity from natural marks in bottlenose dolphin (Tursiops truncatus)
No full textMonitoring trends of animal population is known as an essential part of conservation issues. Although individuals of many cetacean species have distinctive natural variation in appearance which allows identification of individuals through field photography of free-ranging individuals, the use of mark-recapture methods involves several assumptions. The most important assumption is that every animal should have equal probability of being captured within any sampling occasion. In photo-id studies of bottlenose dolphins (Tursiops truncatus) photographs of dorsal fin have been used for matching. Marks on animal were not equally distributed in the population, due to the fact that some individuals are unmarked or with not so visible mark, while others have very large marks that make them easily recognized. The goal of this study was to identify potential heterogeneity in capture probabilities between females and the rest of population. 6550 photographs were taken over four year sampling in both Ligurian and Northern Tyrrhenian Sea. Only high quality pictures were selected from the catalog and used for examination. We analyzed 492 photographs (247 left sides, 245 right sides) making a distinction between adults female, identified as the individuals seen in strong association with a calf, and the other components of the population. We identified different type of natural marks: notch, scar, protuding piece, scrape, back indentation, hole, deformation, white coloured area. Finally the prevalence, abundance and intensity of each mark types have been assessed in order to underline heterogeneity between the two groups analysed
ANALYSE DU COMPORTEMENT DES TURSIOPS TRUNCATUS EN PRESENCE DE CHALUT - Influence of trawling on behaviour and Surfacing rates of bottlenose dolphin in northern thyrrenian sea
No full textLe grand dauphin (Tursiops truncatus) est une espèce opportuniste, principalement ichtyophage, pouvant se nourrir de poissons, céphalopodes et crustacés appartenant au domaine nectonique et benthonique. Les interactions entre pêche et grand dauphin sont fréquemment observées et
documentées, cela, quelques soient les techniques de pêche (Northridge et Hofmann, 1999). Ces interactions peuvent avoir d'importantes conséquences sur le rendement de la pêche et sur la conservation des cétacés (Perrin et al., 1994; Hall et Donovan, 2002). Cette étude analyse le comportement spécifique de l'espèce en présence de chalut. Les données relatives aux immersions/émersions enregistrées durant le suivi réalisé pour cette étude sont analysées de manière à
évaluer l'influence de la technique de pêche sur le comportement respiratoire de l'espèce. Cette étude,
réalisée dans l'Archipel toscan de 2005 à 2007, reporte 70 observations. Dans 33 % des cas, une interaction directe entre les dauphins et la chalutage a eut lieu. Dans l'Achipel toscan, le chalutage cible surtout les fonds de moins de 200m, et plus particulièrement les fonds inférieurs à 100m. Cette
étude prend pour exemple, cinq cas d'interactions et montre que généralement les animaux suivent la route linéaire du chalut seulement lors de la phase de chalutage. L'analyse statistique sur le comportement en surface des animaux indique une variation significative liée à la présence du
chalutage.
Bottlenose dolphin (Tursiops truncatus) is an opportunistic species that feeds both on nectonic and benthic preys such as cephalopods, crustaceans and fishes. Interactions between fisheries and bottlenose dolphins have been observed and well studied all around the world and for different fishing techniques (Northridge et Hofmann, 1999). The interactions lead to negative impacts both on fishing catch and on cetacean conservation ). This study deals with specific bottlenose dolphin behaviour in the presence of trawlers. We analysed surfacing behaviour during the monitoring dedicated to
determine how trawling influence bottlenose dolphin behaviour. Monitoring surveys took place in Tuscan archipelago from 2005 to 2007 during which 70 sightings have been collected. For 33% of sightings, we recorded direct interactions between dolphins and fisheries. In this area, trawling always occurred on sea bottom not deeper than 200m and preferably on 100m isobath. We paid attention to five cases of interactions. Results indicate that in all cases individuals follow the trawler's head only during haul. Surfacing pattern analysis indicates a significant difference between behaviour with and without trawlers
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
CETUS: Cetacean monitoring surveys in the Eastern North Atlantic
No full textData is provided in the recent OBIS-ENV-DATA format, and comprises 8913 georeferenced positions associated with 3195 occurrences of 44 marine taxa.-- 3 filesThe CETUS dataset contains effort-based occurrence records collected during a cetacean monitoring programme in the Eastern North Atlantic, since 2012This research was partially funded by the EU FEDER/FEMP and Portuguese Foundation for Science and Technology (FCT) under the Portugal2020 (Lisboa2020, Algarve2020 and MAR2020) Programme through project OBSERVA.PT (MAR-01.04.02-FEAMP-0002)Peer reviewe
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