Academic literature on the topic 'Boat-based observations'

We report the presence and status of the Irrawaddy Dolphin Orcaella brevirostris in the Hooghly River of West Bengal, India. These observations were made while conducting our field work on the Ganges River Dolphin, which involved vessel-based surveys as well as intensive monitoring from an anchored boat.

Conducting behavioral observations of obligate marine animals such as cetaceans and sirenians is challenging. These animals usually spend prolonged periods beneath the surface of the water out of view of a boat-based or land-based observer. Observations from high vantage points can overcome some of these difficulties by allowing the observer to look down through the water and view subsurface behaviors. I developed a “blimp-cam”: a video camera mounted on a small ovoid-shape, helium-filled aerostat (blimp). This new style of blimp had a number of advantages over previous systems that have used the traditional zeppelin style, including being smaller, cheaper and easier to operate. The “blimp-cam” was flown at a height of 50 m, providing an overhead view of dugongs at water depths of up to 4 m and distances up to 200 m. I used the “blimp-cam” to obtain information on dugong behavior. I assess the advantages of this new style of aerial video observation system, its limitations and potential applications in the marine environment.

From 1994–2007 Ceredigion County Council and a network of shore-based, volunteer observers monitored levels of boat traffic and the occurrence of bottlenose dolphins Tursiops truncatus at seven sites on the coast of Cardigan Bay, Wales. We report high rates of site use and site occupancy by this species during the summer: at Mwnt for example, dolphins were recorded in >80% of 2 hours' observation periods; and at New Quay Harbour dolphins were present in >30% of all 15-minute intervals. At Mwnt and Aberporth there was a significant annual trend for increasing sighting rates; at Ynys Lochtyn a positive trend was only marginally non-significant; at New Quay Bird's Rock the trend was ambiguous but appeared stable over the seven most recent years. Although trends in site use may not reflect population trends in the wider region, these data were consistent with recent abundance estimates that indicate that the number of bottlenose dolphins using Cardigan Bay is stable or slightly increasing. Average group size at our study sites was small (<3 animals), which contrasts with observations of larger schools of the same population elsewhere in their range. The predominant behaviour in coastal Cardigan Bay is demersal foraging, often by solitary animals in shallow near-shore habitats. There was evidence that boat traffic suppressed site use by dolphins at New Quay Harbour, the busiest monitoring site: sighting rates fell when high numbers of boats were present and sighting rates were higher in 2007 than in previous years, when boat use was reduced due to poor weather during the main tourist season. This study demonstrates that networks of volunteer observers can provide a cost-effective, non-invasive means of gathering data on marine mammals for the purposes of coastal zone management.

This paper concerns crosslinguistic differences in the acceptability of so-called relative clause extraction constructions, exemplified by the unacceptable English sentence *This boat I know the guy that owns(associated with the acceptable canonical sentenceI know the guy that owns this boat). It has sometimes been argued, since Ross (1967), that such extractions are universally blocked by a syntactic constraint. However, following observations of such structures in English and other languages, some linguists have argued that such sentences have varying degrees of acceptability and that the degree of acceptability depends on attention limits and pragmatic foregroundedness/backgroundedness. Another view which appears to have gained ground in recent years is one where the degree of acceptability is directly related to processing difficulty. The analysis presented in this paper is based on a comparison between English and Swedish, and includes authentic data, examples previously discussed in the literature, as well as acceptability-tested invented sentences. In the end it will be argued that, while the dominance- and processing-based proposals are on the right track, there is a more plausible and straightforward way of explaining the observed crosslinguistic variation using the theoretical framework of Construction Grammar. Thus, an alternative account will be presented drawing on general principles which are well established within cognitive- and construction-based theories.

In wildlife biology, it is important to conduct efficient observations and quantitative monitoring of wild animals. Conventional wildlife monitoring mainly relies on direct field observations by the naked eyes or through binoculars, on-site image acquisition at fixed spots, and sampling or capturing under severe areal constraints. Recently, remotely piloted aircraft systems (RPAS), also called drones or unmanned aerial vehicles (UAV), were successfully applied to detect wildlife with imaging sensors, such as RGB and thermal-imaging sensors, with superior detection capabilities to those of human observation. Here, we review studies with RPAS which has been increasingly used in wildlife detection and explain how an RPAS-based high-resolution RGB image can be applied to wild animal studies from the perspective of individual detection and population surveys as well as behavioral studies. The applicability of thermal-imaging sensors was also assessed with further information extractable from image analyses. In addition, RPAS-based case studies of acquisition of high-resolution RGB images for the purpose of detecting southern elephant seals (Mirounga leonina) and shape property extraction using thermal-imaging sensor in King George Island, maritime Antarctica is presented as applications in an extreme environment. The case studies suggest that currently available cost-effective small-sized RPAS, which are capable of flexible operation and mounting miniaturized imaging sensors, and are easily maneuverable even from an inflatable boat, can be an effective and supportive technique for both the visual interpretation and quantitative analysis of wild animals in low-accessible extreme or maritime environments.

DUGONGS (Dugong dugon) are large mammalian herbivores found in tropical and sub-tropical waters from the east coast of Africa to Vanuatu in the western Pacific Ocean (Rice 1998). Foraging studies throughout their range indicate that their diet is dominated by seagrass (Marsh et al. 1982; Preen 1995; Preen and Marsh 1995; Anderson 1998; Das and Dey 1999). Aerial surveys (Marsh and Saalfeld, 1989; Preen et al. 1997), land-based and boat-based observations (Anderson 1982 1994; Aragones 1994) and satellite tracking data (Marsh and Rathbun 1990) indicate that dugong distribution is closely associated with seagrass beds. Algae is known to occur in food samples from dugongs (Heinsohn and Birch 1972; Marsh et al. 1982; Erftemeijer 1994; Preen 1995) but its presence in the diet has been described as incidental (Marsh et al. 1982) or linked to large-scale losses of seagrass (Spain and Heinsohn 1973; Marsh et al. 1982; Preen and Marsh 1995). This note contains opportunistic observations of long-term feeding by D. dugon on algal covered rocky reefs in the Darwin region of the Northern Territory.

The paper presents the effect of the discontinuity of the rails of a ferry boat and the presence of lower modulus insulation material at the gap to the variations of stresses in the insulated rail. The analysis consists of a three-dimensional wheel rail contact model based on the finite element method. One of the results shows that the maximum stress occurs in the subsurface of the railhead of the ferry boat. The ratio of the elastic modulus of the railhead and insulation material is found to alter the levels of stress concentration. Numerical result indicates that a higher elastic modulus insulating material can reduce the stress concentration in the railhead but will generate higher stresses in the insulation material, leading to earlier failure of the insulation material. A general subsurface crack propagation analysis methodology is used for the wheel and rail rolling contact. The fatigue damage in the wheel is calculated using a previously developed mixed-mode fatigue crack propagation model. The advantages of the proposed methodology are that it can accurately represent the contact stress of complex mechanical components and can consider the effect of loading non-proportionality. The effects of wheel diameter, vertical loading amplitude, initial crack size, location and orientation on stress intensity factor range are investigated using the proposed model. The prediction results of the proposed methodology are compared with in field observations. The contact elements were used to stimulate the interaction between a wheel and a railhead. Variations in contact stress fields at various locations of the rail are sensitive to the contact distance. The location of the maximum von Mises stress was shifted to the contact surface as the contact point moves close to the rail end. A higher stress, larger deflection and significant plastic deformation occurring at the rail from ferry boat may lead to deterioration at the rail end.

Side-scan sonar observations conducted at Mito artificial habitat site in the southwest coast off Taiwan, documented the locations of both concrete cubic blocks (more than 10,000 units) and scrapped steel boats (39 units) deployed previously. Based on their geographic locations, the concrete cubic artificial reefs could be grouped into 14 reef sets. About 30% of the reefs were deployed out of the promulgated site area. For the purpose of artificial habitat site identification and fishery resources management, a database structure was designed to accommodate types and positions of reefs, information of reef sets, bathymetric contours, textures of bottom sediments and geomorphological characteristics. The effectiveness of Mito artificial habitat site was evaluated to be positive after the deployment of both concrete block reefs and steel boat reefs.

Abstract A first attempt at analysing interactions between bottlenose dolphins and gillnets along the northeastern coast of Sardinia (Italy) was conducted between October 1999 and December 2004. A new approach was used: combining interviews with fishers with boat-based direct observations and behavioural and group size analysis. Fishers on monitored boats noted 2556 days on which gillnet damage was caused by bottlenose dolphins, 68.7% of the total fishing days, with no difference between seasons. An annual estimate of the number of bottlenose dolphins caught in the gillnets was 1.47 (0.98 immatures and 0.49 adults). In all, 317 days were spent making observations at sea, of which 330.6 h were spent directly observing the dolphins. There were no changes in the distribution of daily encounter rate among seasons, group size, or number of immatures, in the presence or the absence of gillnets. However, bottlenose dolphins spent more time both in the study area and feeding when gillnets were present. The extent of the estimated bycatch is worrisome in terms of the ability of bottlenose dolphins off Sardinia to sustain such an annual loss.

Since the 1892 discovery of the Atlantic humpback dolphin Sousa teuszii (Delphinidae), a species endemic to coastal western Africa, from a skull collected in Cameroon, not a single record has been documented from the country or neighbouring countries. Increasing concern about the continued existence of the Gulf of Guinea population of S. teuszii or “Cameroon dolphin” prompted an exploratory survey in May 2011. Shore-based effort, on foot (30.52 km; 784 min), yielded no observations. Small boat-based surveys (259.1 km; 1008 min) resulted in a single documented sighting of ca. 10 (8–12) Cameroon dolphins in shallow water off an open sandy shore near Bouandjo in Cameroon's South Region. The combination of a low encounter rate of 3.86 individuals (100 km)−1 suggesting low abundance and evidence of both fisheries-caused mortality and of habitat encroachment raises concerns about the Cameroon dolphin's long-term conservation prospect. Our results add to indications concerning several other S. teuszii populations that the IUCN status designation of the species as “Vulnerable” may understate its threat level.

Dolphins are increasingly coming into contact with humans, particularly where tourism is involved. It has been assumed that such contact causes chronic stress on dolphin populations. This study examined relatively naive populations of Hector's dolphins and their interaction with various watercrafts. Dolphins in New Zealand have been observed using theodolites and boat-based observations over the last two decades, particularly on the east side of the South Island at Akaroa, which is situated on the coast line of Banks Peninsula. This research was undertaken using shore-based theodolite tracking to observe boat activity around the coast of Lyttelton and Timaru and their associated Harbours. Observations were made mostly over two periods each of six months duration and included the months October through to March during the years 2000-2001 and 2001-2002. Observations made during a third period in 2005 were also incorporated for some of the analyses. Field investigations using a theodolite included more than 376 hours/site/season and recorded dolphin behaviour both with and without the presence of tour boats. Of primary interest were the tours, which ran regular trips to observe Cephalorhynchus hectori in their natural habitat. Hector's dolphins at both Lyttelton and Timaru were consistently observed with particular boat types and not with other types of water craft. Dolphins at Timaru exhibited a greater range of behaviours than those at Lyttelton. Stress-related behaviours such as an increase in swimming speed to open ocean and grouping behaviour were only observed in the presence of boats. Other potential stress behaviours, such as head slaps and repeated tail slaps, were only performed in the absence of boats. Observations implied that some generic dolphin behaviours, which often indicate stressed individuals may not apply to Hector's dolphins, and therefore question the assumption that all dolphin species behave in similar ways. We suggest that low-level tourist boat activity is not placing undue stress on the population. In addition to theodolite observations, tour boat based observations of Hector's dolphin were undertaken and behaviour at each site recorded for a focal animal. Tour boat-based observations concentrated on determining any preference to bow, stern, portside and starboard sides of the vessel. Dolphins consistently showed a preference in direction of approach and departure from tour vessels with a strong tendancy to the bow of the boat, and least with the stern. These results were similar irrespective of site or vessel. Behaviour data were also collected from tour boat vessels over 48 trips/season/site and the data divided into transitional behaviour groups, which included stress behaviours, association / interaction behaviour and neutral behaviour. Behavioural count and time data were collected to reflect the number of times and duration of behaviour occurrence, particularly in relation to transitional behaviours. Determining the presence of stress in Hector's dolphins varied between the data sets and indicated that time is a necessary factor when attempting to determine whether an individual or a general population is genuinely stressed. Quadrant preference and swimming direction in relation to the Black Cat were observed over six years, and both count and time data were collected with regard to behaviour. The results were consistent with preference in quadrant being expressed towards the bow of the boat and least with the stern. The count data suggested no significant impact on Hector's dolphin behaviour in the presence of the Black Cat over time, where time data indicated there was a transition over the years from neutral behaviour in the second year of tour boat activity, to positive behaviour in the third year of boat-activity and finally avoidance behaviour in the seventh year of tour boat activity at Lyttelton Harbour in response to the presence of the Black Cat.

Thus far little has been said about how maps are employed in activism to unleash sentiments. Employing as a lens the emotional turn currently influencing geography, this article looks at a 15M map, a cartographic animation that shows a ‘connected multitude’ of indignad@s as they demonstrated in Spain in 2011; the ‘Left-to-die boat’ map, tracing the course of a ship in which 63 refugees lost their lives; and the ‘Western Africa missing fish’ map, which shows foreign fishing vessels operating irregularly in African waters. Interviews, fieldwork, and participatory observation are employed to understand how maps are designed to activate people through emotions. Based on DeSoto (2014) and Muehlenhaus (2013), the chapter also offers a taxonomy as a heuristic tool.

Iceland is becoming a popular venue for nature-based tourism enthusiasts interested in exploring Arctic environments for scenic and recreational purposes (ITB 2009; Gossling and Alkimou 2006). Visitation to Iceland is expanding exponentially, generating significant revenue and income, making tourism the third largest foreign currency earner for the Icelandic economy. In 2006, total tourism receipts were measured at 47 billion Icelandic kroner (ISK), contributing 4.1 per cent to the nation’s GDP, and providing 12.7 per cent of the country’s income from foreign sources (Rannsoknir and Radgjof Ferdapjonustunnar 2008). In 2007, over 530,000 international tourists visited Iceland with over 80 per cent first-time visitors mainly from Europe and North America (Rannsoknir and Radgjof Ferdapjonustunnar 2008). The Icelandic Tourism Board (ITB 2007) identifies that the vast natural resources - glaciers, volcanos, geysers, and untamed wilderness - are some of the most important reasons contributing to the present 7 percent annual growth rate in visitation (Gossling and Hultman 2006). The most popular leisure activity of visitors is nature observation (ITB 2007). Outdoor activities such as camping, hiking, boat tours, jeep and glacier tours, snowmobile excursions, and horseback riding are also popular throughout the island. Overall, visitor motivation to Iceland is based on romanticized notions of the unique wilderness and the grandness of the landscape and tourist experiences that recreate a ‘natural’ image of the island (Gossling and Alkimou 2006; Gossling and Hultman 2006).

<p>In the Scandinavian countries it is common practice for all surfaces of civil structures to be inspected at least every 5-6 years. However, due to insufficient funds and a highly competitive market, not all surfaces are inspected at a hand-near distance. Most often, hands-on inspections are performed by foot, using a lift, by boat or by rope access, typically resulting in an extensive time consumption for large structures. These methods have not changed much over the last decades despite the technical development.<p>Since 2012, COWI has been using Unmanned Aircraft Vehicles (UAVs) for a large number of inspection projects ranging from the simplest jobs such as documenting and calculating volumes of sand piles to complex tasks of, for example, multispectral imaging for environmental analysis.<p>As a natural development, this service evolved and in collaboration with COWIs bridge inspectors a number of trials with UAV inspection on Danish bridges were performed. The first trials were performed to establish a common understanding between bridge inspectors and drone pilots. The bridge inspectors quickly realized the challenge of locating each observation by video due to the comprehensive size of the structure and the many identical spans. Therefore, COWI developed a new tool "COWI Virtual Inspection" (CVI), where a 3D model can be created based on the images from the UAV inspection and on top of this surface model, the images are applied. The new CVI tool has made it easy to locate each visual damage.<p>This has resulted in a new approach for principal inspection of large bridges and will for large structures reduce the hours spent significantly as well as the amount of traffic interruption.<p>In the future, structures can automatically be screened by UAVs, where image recognition software will be able to point out relevant areas, where a hand-near inspection is needed.