Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Biology; and the Woods Hole Oceanographic Institution), 2016. / Cataloged from PDF version of thesis. / Includes bibliographical references. / To maintain the benefits of group membership, social animals need mechanisms to stay together and reunite if separated. This thesis explores the acoustic signals that dolphins use to overcome this challenge and mediate their complex relationships in a dynamic 3D environment. Bottlenose dolphins are the most extensively studied toothed whale, but research on acoustic behavior has been limited by an inability to identify the vocalizing individual or measure inter-animal distances in the wild. This thesis resolves these problems by simultaneously deploying acoustic tags on closely-associated pairs of known animals. These first reported deployments of acoustic tags on dolphins allowed me to characterize temporal patterns of vocal behavior on an individual level, uncovering large variation in vocal rates and inter-call waiting time between animals. Looking more specifically at signature whistles, a type of call often linked to cohesion, I found that when one animal produced its own signature whistle, its partner was more likely to respond with its own whistle. To better evaluate potential cohesion functions for signature whistles, I then modeled the probability of an animal producing a signature whistle at different times during a temporary separation and reunion from its partner. These data suggest that dolphins use signature whistles to signal a motivation to reunite and to confirm identity prior to rejoining their partner. To examine how cohesion is maintained during separations that do not include whistles, I then investigated whether dolphins could keep track of their partners by passively listening to conspecific echolocation clicks. Using a multi-pronged approach, I demonstrated that the passive detection range of echolocation clicks overlaps with the typical separation ranges of Sarasota mother-calf pairs and that the amount of time since an animal was last able to detect a click from its partner helped explain its probability of producing a signature whistle. Finally, this thesis developed a portable stereo camera system to study cohesion in situations where tagging is not possible. Integrating a GPS receiver, an attitude sensor and 3D stereo photogrammetry, the system rapidly positions multiple animals, grounding behavioral observations in quantitative metrics and characterizing fine-scale changes that might otherwise be missed. / by Nicholas Blair Wootton Macfarlane. / Ph. D.

Marine protected areas (MPAs) are increasing in popularity as a tool to manage fish stocks through conservation of entire habitats and fish assemblages. Quantifying the habitat use, site fidelity, and movement patterns of marine species is vital to this method of marine spatial planning. The success of these protected areas requires that sufficient habitat is guarded against fishing pressure. For large animals, which often have correspondingly large home range areas, protecting an entire home range can be logistically challenging. For MPAs to successfully protect large top predator species, it is important to understand what areas of a home range are especially important, such as breeding and feeding grounds. New technologies, such as acoustic telemetry, have made it possible to track marine animal movements at finer spatial and temporal scales than previously possible, better illuminating these spatial use patterns. This study focused on the movement patterns of great barracuda (n=35), an ecologically important top predator, around Buck Island Reef National Monument, a no-take MPA in St. Croix, U.S.V.I. managed by the National Park Service. As developing standardized methods for acoustic telemetry is still a work in progress, the first half of this study focuses on determining appropriate tools for generating home range size estimates for great barracuda and analyzing ecological parameters driving these results. The second half of this study focused on the use of network analysis to look at spatial divisions within individual home ranges and to compare individual to population level spatial patterns, as well as to generate a relative estimate of population density within the park. Barracuda within the park demonstrated high site fidelity to individual territories, but at the population level they consistently used all habitats within the array. Core use areas within home ranges were evenly distributed throughout all habitats monitored by the acoustic array, although movement corridors were detected along high rugosity reef structures. Greater population densities within the park indicate that density dependent behaviors may be influencing habitat use within the park, and suggest that barracuda are contributing high levels of top down pressure through predation within the park boundaries.

This thesis presents an evaluation of the performance, in terms of throughput and latency, of two Media Access Control (MAC) mechanisms in Underwater Acoustic Networks (UANs), using a model designed in the COTS simulation tool OPNET 10.5. The carrier sense multiple access with collision avoidance is the predominant approach for implementing the MAC mechanism in UANs. However, the underwater acoustic environment is characterized by extreme propagation delays and limited bandwidth, which suggests that an Aloha-like scheme may merit consideration. The performance of these two schemes was compared with respect to two topologies: tree and grid. The results showed that an Aloha-like scheme that does not segment messages outperforms the contention-based scheme under all load conditions, in terms of both throughput and latency, for the two topologies. This thesis is the first to establish that Aloha-like MAC mechanisms can be more than a limited alternative for lightly loaded networks; more specifically, they can be the preferred choice for an environment with large propagation delays. / Lieutenant Commander, Portuguese Navy

High data rate acoustic communications become feasible with the use of communication systems that operate at high frequency. The high frequency acoustic transmission in shallow water endures severe distortion as a result of the extensive intersymbol interference and Doppler shift, caused by the time variable multipath nature of the channel. In this research a Single Input Multiple Output (SIMO) acoustic communication system is developed to improve the reliability of the high data rate communications at short range in the shallow water acoustic channel. The proposed SIMO communication system operates at very high frequency and combines spatial diversity and decision feedback equalizer in a multilevel adaptive configuration. The first configuration performs selective combining on the equalized signals from multiple receivers and generates quality feedback parameter for the next level of combining. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Habitat use of mesophotic coral reefs by sharks is largely unknown. However, it is well established that mesophotic reefs are the site of spawning aggregations for many species of teleost fish. These aggregations represent seasonal concentrations of potential prey biomass that may influence the habitat use of predatory species such as large sharks. I employed acoustic monitoring to examine the movements of three shark species lemon shark (Negaprion brevirostris), tiger shark (Galeocerdo cuvier), and Caribbean reef shark (Carcharhinus perezi)] to determine 1) the comparative spatiotemporal patterns of mesophotic reef habitat use by the three shark species and 2) the spatiotemporal relationship between these sharks and grouper spawning aggregations at a fish spawning aggregation (FSA) site (Hind Bank and Grammanik Bank) along the southern reef shelf edge off St. Thomas, United States Virgin Islands (USVI). Tiger and lemon sharks were detected across nearly the entire acoustic array, which spanned ~ 1060 km2. When present, Caribbean reef sharks used a much smaller activity space, composed exclusively of mesophotic reef habitat located within FSA sites. Individuals from all three species were typically detected for stretches of several consecutive days, while periods without detections usually lasted less than one week. Lemon sharks were present at the FSA site more often during the grouper spawning season (Dec-May) than the non-spawning season (Jun-Nov), but showed no preference toward specific areas within the FSA site, which varied by location and grouper species composition. In contrast, there was no relationship between the presence of tiger and Caribbean reef sharks at the FSA site and the grouper spawning season. My results suggest that despite different habitat use patterns and varying degrees of fidelity, this mesophotic reef serves as an important habitat to all three shark species.

Entre 2011 et avril 2017, La Réunion a connu 22 attaques de requin, dont 9 mortelles. Cette intensification des Conflits Hommes-Requins (CHR) à La Réunion a donné naissance au programme de recherche, CHARC, dont le but est de mieux comprendre la biologie et l'écologie des requins bouledogue (Carcharhinus leucas). C'est dans ce contexte et au sein de ce programme que s'est réalisé ce projet de thèse. Représentant la première étude de ce type sur cette espèce, l'objectif principal de la thèse a été de déterminer les caractéristiques et les particularités de la population observée, de délimiter son habitat et ses micro-habitats, d'en étudier son occupation spatiale et temporelle et de comprendre le rôle de ces micro-habitats dans le cycle de vie de l'espèce. Pour atteindre ces objectifs, l'étude repose sur une campagne de marquage et le suivi acoustique passif des 35 requins bouledogue le long de la côte ouest pendant 18 mois. La quasi-totalité des requins marqués sont des adultes de grande taille, avec un sex-ratio en faveur des femelles. De part ces caractéristiques, cette population de requins bouledogue se distingue de la majorité des autres populations observées à travers le monde.L'occupation spatiale et temporelle des requins n'était pas homogène, avec l'utilisation de zones préférentielles et une forte saisonnalité. On observe également une variabilité individuelle, influencée par la taille et le sexe des individus : les jeunes adultes, des deux sexes, sont essentiellement localisés dans le sud de la zone, au cours de deux pics de présence, un hivernal et un estival. A l'inverse, les grandes femelles sont majoritairement localisées dans le nord de la zone, avec un pic de présence hivernal. Les grands mâles sont peu présents et essentiellement localisés dans le nord et à l'extrémité sud de la zone d’étude au cours de la période creuse de juillet à octobre. Indépendamment du sexe et de la taille des individus, les zones préférentielles sont utilisées comme zone de repos sur l'ensemble des périodes nycthémérale et comme zone de chasse nocturne. Certaines zones préférentielles pourraient également jouer un rôle dans la reproduction. Les zones secondaires représentent principalement des zones de passages entre les zones préférentielles ou des zones de chasse nocturne secondaire. Si l'ensemble de ces résultats devra être confirmé par d'autres études à plus grande échelle spatio-temporelle, il montre toute la complexité du comportement et des déplacements des requins bouledogue dans les eaux réunionnaises. Cette thèse ouvre de nouvelles perspectives d'étude, notamment sur l'influence des facteurs environnementaux dans l'occupation spatio-temporelle des requins ou sur l'existence de phénomènes liés à la reproduction comme la philopatrie et la polyandrie. / A serie of 22 shark attacks occurred at Reunion Island between 2011 and April 2017, causing nine deaths. Following the rise of the Human Shark Conflict (HSC), a research program, CHARC, was launched to better understand the biology and ecology of bullshark (Carcharhinus leucas). This thesis was carried out within this program. Representing the firststudy on this specie at Reunion Island, the main objective was to determine characteristics of the observed population, to define it habitat and its micro-habitats, to study its spatial and temporal occupation and to understand the role of these micro-habitats in the life cycle of the specie. This study is based on a tagging campaign and passive acoustic telemetry of 35 bullsharks along the west coast for 18 months. Almost all tagged sharks are adults, large in size and with a sex ratio in favor of females. Base of these characteristics, this bullshark population differs from the majority of other observed populations throughout the world. The spatial and temporal occupation was not homogeneous, with use of preferential areas and strong seasonality. Individual variability is also observed, influenced by size and sex: young adults, of both sexes, are mainly located in the southern part of the study area, during two peaks of presence, one in winter and one in summer. Conversely, large females are mostly located in the north of study area, with a peak of presence in winter. Large males are rarely present and mostly located at the ends of the north and south of the study area from July to October. Apart from sex and size of individuals, preferential areas are used as resting areas, during all nycthemeral periods and as hunting area at night. Some preferential areas may also play a role in breeding behaviour. The secondary areas are mainly used to move from a preferential area to another or as secondary hunting area at night. If all these results have to be confirmed by larger-scale spatio-temporal studies, it put in light the complexity of bullshark behavior and movements along the coasts of Reunion Island. This thesis gives perspectives for new studies, including studies on environmental factors influence on spatio-temporal occupation of sharks or on phenomena related to reproduction such as philopatry and polyandry.

The silky shark Carcharhinus falciformis forms the primary elasmobranch bycatch in tuna purse seine fisheries using fish aggregating devices (FADs) in all of the world’s tropical oceans. Its life-history traits of slow growth, late maturation and low fecundity make it vulnerable to over exploitation, as is apparent from historical bycatch trends. Very little is known about the associative behaviour of this species with floating objects, information which is essential in formulating effective mitigation and management measures. This study aims to address this knowledge gap through the use of various electronic tagging techniques in conjunction with dietary analysis. Dietary data were collected from 323 silky sharks incidentally caught at FADs. Approximately 40 percent of the diet consisted of prey associated with FADs while the remaining 60 percent were non-associated species of crustaceans, cephalopods and fishes. These results suggest that the associative behaviour is not primarily driven by trophic enhancement, but is likely a combination of predator avoidance, social interactions and feeding. Fine-scale behavioural data from silky sharks associated with drifting FADs were collected through the use of acoustic telemetry techniques. Acoustic tags were implanted into 38 silky sharks (69- 116 cm TL) at eight FADs. FADs were equipped with satellite linked acoustic receivers and abandoned to drift freely. Presence/absence and swimming depth data were telemetered via the Iridium satellite system. A total of 300 d of behavioural data were collected from 20 tagged individuals. Individuals remain associated with the same FAD for extended periods (min = 2.84 d, max = 30.60 d, mean = 15.69 d). Strong diel patterns were observed in both association and swimming depth. Typically individuals moved away from FADs after sunset and return later during the night, then remain closely associated until the following evening. Vertical behaviour also changed around sunset with sharks using fairly constant depths, within the upper 25 m, during the day and switching to rapid vertical movements during the night, with dives in excess of 250 m recoded. Broader scale movement behaviour was investigated using pop-up archival satellite tags (PSATs). Tags were deployed on 46 silky sharks (86-224.5 cm TL) for a total of 1495 d. Light data were used to calculate geolocation estimates and reconstruct the sharks’ trajectories. Movement patterns differed between animals and according to deployment duration. Several extensive horizontal movements were observed, with an average track length of 3240 km during an average tag deployment of 44.02 d. Horizontal movement patterns were found to correlate very closely with drift patterns of FADs. Consequently, it appears that the movement behaviour of juvenile silky sharks is strongly influenced by the movement of drifting FADs in this region. Ghost fishing of silky sharks through entanglement in FADs was also investigated using data derived from PSATs as well as underwater visual censuses. Thirteen per cent of the tagged sharks became entangled in FADs and entangled sharks were observed in 35 percent of the 51 FADs surveyed. Using this information in conjunction with estimated time that sharks remained entangled in the FAD (from depth data from PSATs), and scaling up according to estimates of FAD numbers, it was found that between 480 000 and 960 000 silky sharks are killed annually in this manner in the Indian Ocean. Subsequent management measures in this region prevent the deployment of FADs with netting that could lead to entanglement. Overall, floating objects appear to play a significant role in the juvenile life stages of silky sharks in this region. While their association with floating objects is clearly advantageous in an evolutionary sense, under current tuna fishery trends, this behaviour is certainly detrimental for the population.

Predators are key components of aquatic ecosystems and innovative approaches to understanding their spatial distribution are imperative for research, effective management, and conservation. Discontinuities, created by abrupt changes between two unlike entities, are irregularly-distributed, intermediate-scale features that can have a disproportionate effect on organismal distribution within the seascape. Here I use the discontinuity concept to relate the distribution of a predator, striped bass (Morone saxatilis), to physical features within Plum Island Estuary (PIE), MA. I mapped the distribution of 50 acoustically-tagged striped bass during four monthly surveys at 40 sites to evaluate if heterogeneity in physical features concentrated predators. All striped bass survived tagging, were coastal migrants, displayed seasonal residency within PIE, and moved freely throughout the estuary. However, these highly mobile predators were not evenly distributed. Specifically, striped bass were clustered in the middle region of PIE in response to sandbar area, intermediate bottom unevenness, channel networks, and, to a lesser extent, confluences and drop-offs. The highest predator counts occurred at sites with the greatest additive habitat complexity. I measured 23 geomorphic metrics at 40 sites within the seascape to characterize the spatial patterns of confluences, drop-offs, bathymetry and land features. Then, I mapped integrated measurements of multimetric physical features to reveal distinct spatial trends in physical complexity of the estuary. By expanding the discontinuity concept and combining irregularly-distributed, intermediate-scale physical features with smaller-scale, traditional fish habitat methodologies, I revealed consistent and ecologically-meaningful patterns within a north temperate estuarine seascape.

En biologie de la conservation, les pratiques de réintroduction consistent à élever des animaux en captivité et à les relâcher dans l’aire de répartition où l’espèce en question a décliné ou disparu, ceci dans le but de soutenir la population naturelle. Pour les poissons, l’élevage en pisciculture implique une sélection des individus au moment de la reproduction et un développement des jeunes stades dans un environnement contrôlé qui peuvent influencer fortement les attributs comportementaux,génétiques, morphologiques et physiologiques nécessaires pour répondre de manière adéquate aux conditions du milieu naturel. L’exposition de ces individus naïfs, particulièrement les jeunes stades, àla variabilité (environnements enrichis) pourrait limiter ces carences et améliorer la survie post lâcher.Dans ce cadre, des expérimentations sont nécessaires pour comprendre comment l’environnement d’élevage affecte les performances individuelles qui impacteront directement la fitness en milieu naturel et par conséquent l’efficacité des programmes de réintroduction avec un objectif de conservation. La dernière population d’esturgeon sauvage d’Europe de l’ouest est issue de la Gironde (Sud-Ouest France), il s’agit de l’esturgeon européen (Acipenser sturio). Cette espèce est classée en danger critique d’extinction et fait l’objet d’un programme de restauration européen décliné en plans d’actions nationaux en France et en Allemagne. Dans ce travail, cette espèce est utilisée comme modèle afin d’évaluer les effets des pratiques d’élevage sur la survie, la croissance et le comportement des jeunes de l’année en captivité puis leur comportement et leur survie post lâcher en milieu naturel. Des esturgeons nés en captivité, issus de 2 croisements, ont été élevés selon deux méthodes, l’élevage « traditionnel » (faible variabilité spatiale et temporelle) et l’élevage« enrichi » (augmentation de la variabilité spatiale et temporelle), jusqu’à ce qu’ils atteignent trois mois puis leurs performances ont été évaluées en conditions contrôlées. Les individus ont ensuite étaient relâchés en rivière et leurs déplacements individuels ont été suivis pendant 20 jours à l’aide d’une technologie de télémétrie acoustique après avoir évalué les effets du marquage sur les performances individuelles. Les résultats en conditions contrôlées mettent en évidence que dans un élevage enrichi les individus atteignent un poids et une taille supérieurs dès le premier mois de vie.L’analyse de la croissance révèle que les individus issus des deux croisements ont une croissance similaire en conditions enrichies mais celle-ci diffère dans un environnement traditionnel. L’analyse du comportement en milieu contrôlé indique que les individus élevés en conditions enrichies seraient plus lents à explorer un environnement inconnu mais plus nombreux que parmi les individus élevés de manière traditionnelle. Le suivi post-lâcher des jeunes stades de cette espèce et plus largement des espèces d’esturgeon a été réalisé pour la première fois dans le cadre de ce travail. La survie globale des poissons était de 69,3% (52.2−90.9%), la survie la plus faible concernant un croisement élevé de manière traditionnelle. [...] Ce travail milite pour que les pratiques de repeuplement et la recherche sur l’écologie des espèces travaillent en synergie afin de favoriser la mise en place d’une aquaculture adaptative qui soutienne la conservation des espèces. / Stocking for conservation purposes is the practice of raising animals in captivity and releasing the min to an area from which the species have either declined or disappeared, in an attempt to enhance the natural population. Fish reared in hatcheries are exposed to selective reproduction, and early life experiences in a safe setting can strongly influence the behavioral, genetic, morphological and physiological attributes necessary to respond adequately to natural conditions after stocking.Exposing naive individuals to variability during early stages −enriched environment− could reduce such deficiencies and improve fish survival after release. This approach needs to be studied tounderstand how it affects performance traits that will directly impact fish fitness in the wild and consequently, its effects on stocking programs efficiency for conservation. The last remaining wild sturgeon population in Western Europe, the European sturgeon (Acipenser sturio), is located in theGironde (Southwest France). This species is critically endangered and subject of a recovery plan with specific action plans in France and Germany. In this study, this species was used as a model to assess effects of rearing practices on survival, growth and behavioral performance of young-of-the-yearsturgeons before stocking and their behavior and survival in the wild after release. Captive-born sturgeons belonging to two crossings were reared under traditional (i.e. low spatial and temporal variability) and enriched (i.e. higher spatial and temporal variability) practices for 3 months and their performance was evaluated in laboratory. Then, the fish were released in the Dordogne River and their individual movements were tracked for 20 days using a acoustic telemetry system; after evaluating the tagging effects on fish performance. Results in the laboratory demonstrated that enriched environment resulted in bigger fish from the first month. Growth curve analysis revealed that enriched environment made both fish crossings grow in a similar manner. In contrast, crossings’growth differed in traditional rearing. Behaviorally, enriched-reared fish were slower to explore a new environment but more individuals engaged on doing so than traditional-reared fish. Post-release assessment on such small individuals was carried out for the first time for a sturgeon species. Fish over all survival was 69.3% (52.2−90.2%) where the lowest survival was found for one crossing reared under traditional conditions. After release, most movements (85.7%) occurred during the first three days after stocking and downstream direction. During the study, 82% of the fish were detected within 13.5km from the release site and no fish reached the saline estuary. Fish were mainly active during night hours, but traditional-reared fish were significantly more active during the day than enriched-reared fish during the first three days. Our findings advocate for the integration of enriched rearing practices within the juvenile production for release in order to boost the performances linked fitness. Stocking practices and life history research should work together to favor adaptive aquaculture approaches, which support species conservation / En conservación, la repoblación de especies es la práctica de criar animales en cautiverio y suposterior liberación en zonas donde la especie ha disminuido o desaparecido con la finalidad deaumentar la población natural. Los peces cultivados en piscifactorías están expuestos a la reproducción selectiva, y la experiencia temprana en ambientes seguros puede tener una fuerte influencia en los atributos genéticos, morfológicos, fisiológicos y de comportamiento, necesarios para responder adecuadamente en la naturaleza después de la liberación. La exposición de individuos sin experiencia previa a la variabilidad en el ambiente (ambientes enriquecidos) durante los estadios tempranos de su desarrollo puede reducir estas deficiencias y mejorar la sobrevivencia después de la liberación. Este tema necesita ser estudiado más a fondo para entender cómo el ambiente de cría afecta los atributos de rendimiento que influirán directamente en el “fitness” de los individuos una vez en la naturaleza y por consecuencia, en la eficiencia de los programas de repoblación para la conservación. El último relicto de esturión salvaje en el sudoeste de Europa, el esturión europeo (Acipenser sturio), está en peligro crítico de extinción, sujeto a un plan de recuperación y planes específicos de conservación en Francia y Alemania. En este estudio, esta especie fue usada como modelo para evaluar los efectos de las prácticas de cría en la sobrevivencia,crecimiento, y comportamiento en juveniles de menos de un año de edad antes de la liberación y, su comportamiento y sobrevivencia en la naturaleza después de la liberación. Para esto, esturiones de dos cruces diferentes fueron criados durante tres meses en cautiverio en ambientes tradicionales(baja variabilidad espacial y temporal) y ambientes enriquecidos (alta variabilidad espacial ytemporal) y evaluados en laboratorio. Posteriormente los peces fueron liberados en el río Dordoña y se rastrearon sus movimientos individualmente durante 20 días usando un sistema de telemetría; los efectos de este marcado se evaluaron previamente. Los resultados de laboratorio demuestran que la cría enriquecida produce peces de mayor tamaño desde el primer mes de crianza. Los análisis en las curvas de crecimiento revelaron que la cría enriquecida hizo que los peces de ambos cruces crecieran de manera similar. Por el contrario, el crecimiento fue diferente bajo la cría tradicional. Con respecto al comportamiento, los peces de cría enriquecida tardaron más en empezar a explorar un ambiente nuevo pero más individuos se involucraron en esta actividad que los peces de cría tradicional. En la naturaleza, es la primera vez que se monitorea esturiones de tan poca edad. La sobrevivencia global fue del 69.3% (52.2−90.9%) donde uno de los cruces criado tradicionalmente tuvo la tasa más baja.(...) Las prácticas de repoblación y la investigación de historia de vida deben trabajar en conjunto para favorecer los enfoques adaptativos de acuacultura que apoyen la conservación de especies.

Angelerfolg hängt vom Fischverhalten ab und selektiver Fang aufgrund vererbbarer Verhaltensmerkmale kann sich auf Fischpopulationen auswirken. Die anglerische Vulnerabilität ergibt sich aus einer Kombination aus dem Zustand des Fisches, dem Zusammentreffen mit dem Fanggerät und den Eigenschaften desselben. Höhere Aktivität sollte die Begegnungswahrscheinlichkeit mit dem Fanggerät und dadurch die Vulnerabilität steigern. Ziel dieser Arbeit war es zu verstehen, wie Bewegungsmuster die Vulnerabilität durch die Angelfischerei beeinflussen. Dazu habe ich das Verhalten von vier Arten (Karpfen, Cyprinuscarpio, Schleie, Tinca tinca, Barsch, Perca fluviatilis, und Hecht, Esox lucius) in einem See mittels akustischer Telemetrie gemessen. Zudem habe ich verhaltensselektives Angeln auf Benthivore (Karpfen und Schleie) von festen Plätzen mit dem mobilen Angeln auf einen aktiven Raubfisch (Barsch) und einen Lauerjäger (Hecht) verglichen. Barsche wurden gezielt von freiwilligen, unterschiedlich versierten Anglern in GPS-überwachten Booten beangelt, um zu verstehen, wie Anglerfähigkeiten verhaltensbasierte Selektion beeinflussen. Für die individuell wiederholbare Aktivität von Karpfen, Schleie und Barsch lag keine Angelselektivität vor, da das Zusammentreffen mit Fanggeräten in keinem Zusammenhang mit der Vulnerabilität stand. Beim Barsch hingegen hing die Vulnerabilität mit der Habitatwahl zusammen. Die Geschicklichkeit der Angler verstärkte die Selektion durch höhere Mortalität. Für große Hechte mit großem Aktionsradius kann ein auf Begegnungen basierender Mechanismus nicht ausgeschlossen werden. Zusammenfassend lässt sich sagen, dass die wichtigsten Verhaltensweisen, die die Vulnerabilität durch die Angelfischerei ausmachen und nach denen eine Selektion erwartet wird, häufig erst nach dem Zusammentreffen von Fisch und Fischer stattfinden. Jedoch kann die Bedeutung dieser Fisch-Fischer Begegnungen für die Vulnerabilität art- und fischereispezifisch sein. / Capturing fish by angling depends on fish behaviour. Selective capture based on heritable behaviours may have ramifications for fish populations and fishing communities, but the behavioural components of angling vulnerability are unclear. Conceptually, vulnerability derives from a combination of a fish’s internal state, gear encounter rate and gear quality. Accordingly, greater activity or space use is expected to increase vulnerability via elevated encounter rates with fishing gear. However, behaviourally selective angling may also interact with angler behaviour (e.g. skill). My aim was to understand the role of fish movement and space use in driving angling vulnerability. I measured the behaviour and angling vulnerability of four species (viz. carp, Cyprinus carpio, tench, Tinca tinca, perch, Perca fluviatilis, and northern pike, Esox lucius) using whole-lake high resolution acoustic telemetry. Perch were targeted by variably skilled anglers in GPS tracked boats to understand how skill affects selection. I have therefore contrasted behaviourally selective angling of benthivores (carp and tench) targeted from fixed angling sites, an active top predator (perch) targeted by searching anglers and an ambush predator (northern pike) targeted by searching anglers. Angling was unselective for repeatable carp, tench or perch activity and movement as encounter was unrelated to vulnerability. Vulnerability related to perch habitat choice as shown by a latitudinal division of captured and uncaptured perch and high skilled anglers only strengthened selection via greater enacted mortality. Finally, large pike with greater space use were most vulnerable to angling and an encounter based mechanism cannot be ruled out. In conclusion, the key behaviours distinguishing angling vulnerability, upon which selection should be expected, frequently operate after a fish-fisher encounter, but the importance of fish-fisher encounters for vulnerability may be species and fishery specific.