Kelp Marine Research

Hoorn, Netherlands

Kelp Marine Research

Hoorn, Netherlands

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Oudejans M.G.,Dulra Research | Oudejans M.G.,Kelp Marine Research | Visser F.,Kelp Marine Research | Visser F.,Leiden University | And 4 more authors.
PLoS ONE | Year: 2015

Bottlenose dolphin stock structure in the northeast Atlantic remains poorly understood. However, fine scale photo-id data have shown that populations can comprise multiple overlapping social communities. These social communities form structural elements of bottlenose dolphin (Tursiops truncates) populations, reflecting specific ecological and behavioural adaptations to local habitats. We investigated the social structure of bottlenose dolphins in the waters of northwest Ireland and present evidence for distinct inshore and offshore social communities. Individuals of the inshore community had a coastal distribution restricted to waters within 3 km from shore. These animals exhibited a cohesive, fissionfusion social organisation, with repeated resightings within the research area, within a larger coastal home range. The offshore community comprised one or more distinct groups, found significantly further offshore (>4 km) than the inshore animals. In addition, dorsal fin scarring patterns differed significantly between inshore and offshore communities with individuals of the offshore community having more distinctly marked dorsal fins. Specifically, almost half of the individuals in the offshore community (48%) had characteristic stereotyped damage to the tip of the dorsal fin, rarely recorded in the inshore community (7%). We propose that this characteristic is likely due to interactions with pelagic fisheries. Social segregation and scarring differences found here indicate that the distinct communities are likely to be spatially and behaviourally segregated. Together with recent genetic evidence of distinct offshore and coastal population structures, this provides evidence for bottlenose dolphin inshore/ offshore community differentiation in the northeast Atlantic. We recommend that social communities should be considered as fundamental units for the management and conservation of bottlenose dolphins and their habitat specialisations. © 2015 Oudejans et al.


Anderwald P.,University College Cork | Brandecker A.,University College Cork | Coleman M.,University College Cork | Collins C.,University College Cork | And 7 more authors.
Endangered Species Research | Year: 2013

Marine construction works often lead to temporary increases in vessel traffic, which, in addition to the construction activity itself, contribute to underwater ambient noise in the affected area and increase the risk of vessel collision for marine mammals. Using a 3 yr data set of cliff-based observations, we investigated whether the presence/absence of minke whales, bottlenose dolphins and grey seals varied with the overall number and type of vessels present during the construction of an underwater gas pipeline through a bay on the northwest coast of Ireland. Results from binary generalised estimation equations showed a positive relationship between the presence of bottlenose dolphins and the overall number of boats, as well as the number of construction vessels. However, the presence of the 2 taxa with higher hearing sensitivity at low frequencies- minke whales and grey seals-was negatively correlated with the total number of boats and the number of utility vessels (as well as the number of fishing boats in the case of minke whales). While bottlenose dolphins may have been attracted to either the vessels per se or high prey concentrations coinciding with construction activities, both minke whales and grey seals appear to have been displaced by high levels of vessel traffic, most likely due to noise disturbance. Careful consideration of mitigation measures, especially for taxa with low-frequency hearing, is therefore essential in the planning phase of offshore construction activities, which should also take local circumstances into account. © Inter-Research 2013.


Anderwald P.,University College Cork | Haberlin M.D.,University College Cork | Coleman M.,University College Cork | Ocadhla O.,Siar Environment | And 4 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2012

Long-term monitoring programmes of a comparatively small area complement larger scale, but temporally limited surveys and can provide extensive datasets on seasonal occurrence and fine-scale habitat use of multiple species. A marine mammal monitoring programme, involving year-round, land-based observations, has been conducted in Broadhaven Bay candidate Special Area of Conservation, north-west Ireland, during 2002, 2005 and 2008-2011. Nine cetacean and two seal species have been recorded, with grey seal, harbour porpoise, common and bottlenose dolphins, and minke whale present throughout the year. Generalized additive models, taking into account observer effort, sighting conditions (sea state) and interannual variation, did not reveal any significant seasonal patterns in the occurrence of grey seals, bottlenose dolphins and minke whales. On the other hand, common dolphin presence in Broadhaven Bay was highest during autumn and winter. Bottlenose dolphins could be separated spatially from both common dolphins and minke whales in a classification tree by their preferential use of the shallower inshore areas of the bay (<30 m depth). However, common dolphins and minke whales, which occurred mainly in the deeper outer section of Broadhaven Bay, could not be spatially distinguished from each other, and grey seals were distributed over the entire bay. Broadhaven Bay represents an important marine mammal habitat with respect to overall species diversity and the regular occurrence of bottlenose dolphin, harbour porpoise, grey and harbour seals (all listed under Annex II of the EU Habitats Directive). © 2012 Marine Biological Association of the United Kingdom.


Culloch R.M.,University College Cork | Anderwald P.,Swiss National Park | Brandecker A.,University College Cork | Haberlin D.,University College Cork | And 6 more authors.
Marine Ecology Progress Series | Year: 2016

During the construction of a gas pipeline from an offshore gas field in northwest Ireland, a year-round shore-based marine mammal monitoring programme was undertaken. Using 6 yr of data, generalised estimating equations-generalised additive models (GEE-GAMs) were used to investigate if construction-related activity and vessel traffic influenced the occurrence of common dolphin, minke whale, harbour porpoise and grey seal within the area where the pipeline made landfall. Construction-related activity reduced harbour porpoise and minke whale presence, whilst an increase in vessel numbers (independent of construction-related activity) reduced common dolphin presence. All species showed some degree of annual and seasonal variation in occurrence. For common dolphins and harbour porpoises, we found similar seasonal patterns to those reported in broader Irish waters, which tentatively suggests that seasonal patterns persisted irrespective of construction-related activity or vessel traffic, indicating that any impact might have been only short-term. Multiple construction-related activities occurred simultaneously in different areas, and the inter-annual variation may, in part, be an indication of variation in species' re-sponse to particular activities, their intensity and their location. However, the precise location of the activities was not regularly recorded, limiting our ability to investigate the fine-scale spatio-temporal impact of the diverse range of construction-related activities. Improved communication and coordination between developers, regulators and scientists will help ensure that monitoring programmes are effective and efficient, to better inform our understanding of potential impacts and to mitigate effectively against them for future developments. © 2016 SAMS.


Cure C.,Acoustics Group | Cure C.,University of St. Andrews | Sivle L.D.,Norwegian Institute of Marine Research | Visser F.,Kelp Marine Research | And 7 more authors.
Marine Ecology Progress Series | Year: 2015

Anti-predator strategies are often defined as 'flight' or 'fight', based upon prey anatomical adaptations for size, morphology and weapons, as well as observed behaviours in the presence of predators. The humpback whale Megaptera nova eangliae is considered a 'fight' specialist based upon anatomy and observations of grouping behaviour and active defence when attacked by killer whales. However, the early stage of humpback whale anti-predator strategy, when the prey detects the presence of a distant potential predator that may not have perceived it, has never been described. Our aim was to experimentally examine this initial stage of anti-predator responses. Humpbacks are likely to hear well at the frequencies of killer whale vocalisations, thus the perception of killer whale sounds could trigger anti-predator responses. To address this hypo thesis, we played mammal-eating killer whale sounds to 8 solitary or paired humpback whales in North Atlantic feeding grounds and monitored their behavioural responses. We found that predator sound playbacks induced a cessation of feeding, a change in the diving pattern and a clear directional and rapid horizontal avoidance away from the speaker. Interestingly, in mother-calf pairs with young calves, the directional horizontal avoidance was atypically alternated by 90 degree turns, which may serve as a mechanism to better track the pre dator or a stealth tactic when more vulnerable animals are present. These results provide experimental evidence that humpback whales can exhibit a strong horizontal avoidance as an initial stage of anti-predator defence, indicating that anti-predator responses may be more graded and mixed than previously recognized. © Inter-Research 2015.


PubMed | Applied Scientific Research, University of St. Andrews, Norwegian Institute of Marine Research, Kelp Marine Research and 2 more.
Type: | Journal: Advances in experimental medicine and biology | Year: 2015

In mitigating the risk of sonar operations, the behavioral response of cetaceans is one of the major knowledge gaps that needs to be addressed. The 3S-Project has conducted a number of controlled exposure experiments with a realistic sonar source in Norwegian waters from 2006 to 2013. In total, the following six target species have been studied: killer, long-finned pilot, sperm, humpback, minke, and northern bottlenose whales. A total of 38 controlled sonar exposures have been conducted on these species. Responses from controlled and repeated exposure runs have been recorded using acoustic and visual observations as well as with electronic tags on the target animal. So far, the first dose-response curves as well as an overview of the scored severity of responses have been revealed. In this paper, an overview is presented of the approach for the study, including the results so far as well as the current status of the ongoing analysis.


Visser F.,University of Amsterdam | Visser F.,Nova Atlantis Foundation | Visser F.,Kelp Marine Research | Hartman K.L.,Nova Atlantis Foundation | And 5 more authors.
Marine Ecology Progress Series | Year: 2011

Each year, a phytoplankton spring bloom starts just north of the North Atlantic Subtropical Gyre, and then expands northwards across the entire North Atlantic. Here, we investigate whether the timing of the spring migration of baleen whales is related to the timing of the phytoplankton spring bloom, using 4 yr of dedicated whale observations at the Azores in combination with satellite data on ocean chlorophyll concentration. Peak abundances of blue whale Balaenoptera musculus, fin whale B. physalus, humpback whale Megaptera novaeangliae and sei whale B. borealis were recorded in April-May. The timing of their presence tracked the onset of the spring bloom with mean time lags of 13, 15, 15 and 16 wk, respectively, and was more strongly related to the onset of the spring bloom than to the actual time of year. Baleen whales were actively feeding on northern krill Meganyctiphanes norvegica in the area, and some photo-identified individuals stayed in Azorean waters for at least 17 d. Baleen whales were not observed in this area in autumn, during their southward migration, consistent with low chlorophyll concentrations during summer and autumn. Our results support the hypothesis that baleen whales track the secondary production generated by the North Atlantic spring bloom, utilizing mid-latitude areas such as the Azores as foraging areas en route towards their summer feeding grounds. © 2011 Inter-Research.


Cure C.,University of St. Andrews | Antunes R.,University of St. Andrews | Samarra F.,University of St. Andrews | Alves A.C.,University of St. Andrews | And 4 more authors.
PLoS ONE | Year: 2012

In cetaceans' communities, interactions between individuals of different species are often observed in the wild. Yet, due to methodological and technical challenges very little is known about the mediation of these interactions and their effect on cetaceans' behavior. Killer whales (Orcinus orca) are a highly vocal species and can be both food competitors and potential predators of many other cetaceans. Thus, the interception of their vocalizations by unintended cetacean receivers may be particularly important in mediating interspecific interactions. To address this hypothesis, we conducted playbacks of killer whale vocalizations recorded during herring-feeding activity to free-ranging long-finned pilot whales (Globicephala melas). Using a multi-sensor tag, we were able to track the whales and to monitor changes of their movements and social behavior in response to the playbacks. We demonstrated that the playback of killer whale sounds to pilot whales induced a clear increase in group size and a strong attraction of the animals towards the sound source. These findings provide the first experimental evidence that the interception of heterospecific vocalizations can mediate interactions between different cetacean species in previously unrecognized ways. © 2012 Curé et al.


Visser F.,Applied Scientific Research | Visser F.,University of Amsterdam | Visser F.,Kelp Marine Research | Miller P.J.O.,University of St. Andrews | And 8 more authors.
Behaviour | Year: 2014

Long-finned pilot whales (Globicephala melas) are highly social cetaceans that live in matrilineal groups and acquire their prey during deep foraging dives. We tagged individual pilot whales to record their diving behaviour. To describe the social context of this individual behaviour, the tag data were matched with surface observations at the group level using a novel protocol. The protocol comprised two key components: a dynamic definition of the group centred around the tagged individual, and a set of behavioural parameters quantifying visually observable characteristics of the group. Our results revealed that the diving behaviour of tagged individuals was associated with distinct group-level behaviour at the water's surface. During foraging, groups broke up into smaller and more widely spaced units with a higher degree of milling behaviour. These data formed the basis for a classification model, using random forest decision trees, which accurately distinguished between bouts of shallow diving and bouts of deep foraging dives based on group behaviour observed at the surface. The results also indicated that members of a group to a large degree synchronised the timing of their foraging periods. This was confirmed by pairs of tagged individuals that nearly always synchronized their diving bouts. Hence, our study illustrates that integration of individual-level and group-level observations can shed new light on the social context of the individual foraging behaviour of animals living in groups. © Copyright 2014 by Koninklijke Brill NV, Leiden, The Netherlands.


Aoki K.,University of Tokyo | Sakai M.,University of Tokyo | Miller P.J.O.,University of St. Andrews | Visser F.,University of Amsterdam | And 2 more authors.
Behavioural Processes | Year: 2013

Synchronous behavior, as a form of social interaction, has been widely reported for odontocete cetaceans observed at the sea surface. However, few studies have quantified synchronous behavior underwater. Using data from an animal-borne data recorder and camera, we described how a pair of deep-diving odontocetes, long-finned pilot whales, coordinated diving behavior. Diving data during overlapping periods of 3.7. h were obtained from two whales within a stable trio. The tagged whales made highly synchronous movements, and their dive durations differed only slightly (3. ±. 3. s). The pair of whales maintained a constant and narrow vertical separation (ca. 3. m) throughout synchronous dives. The overall fluking rate for the same travel speed during synchronous dives was virtually the same as that during asynchronous dives, suggesting that synchronous behavior did not affect locomotion effort. In addition, a possible affiliative behavior was recorded by the animal-borne camera: another individual appeared in 8% of the frames, both with and without body contact to the tagged whale. The primary type of body contact was flipper-to-body. Our study, the first on underwater synchronous behavior and body contact of pilot whales, highlights the utility of using animal-borne devices for enabling new insights into social interactions. © 2013 Elsevier B.V.

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