Marine Conservation Research International

Kelvedon, United Kingdom

Marine Conservation Research International

Kelvedon, United Kingdom
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Leaper R.,International Fund for Animal Welfare | Renilson M.,Higher Colleges of Technology | Ryan C.,Marine Conservation Research International
Journal of Ocean Technology | Year: 2014

Concerns about the effects of underwater noise pollution from shipping have led to a number of initiatives to develop quieting technologies for large commercial ships. These include the development of non-mandatory technical guidelines for reducing ship noise by the International Maritime Organization. For most merchant vessels the noise generated by cavitation will dominate all other sources of noise from that vessel. In addition, the noisiest vessels will contribute most of the shipping related hydroacoustic noise. The noisiest vessels are also likely to suffer excessive cavitation and may be operating inefficiently. Such vessels may be identified on the basis of efficiency indices or noise measurements and are most likely to benefit from remedial action to reduce noise which may also improve fuel efficiency. Slow steaming practices since 2007 resulted in an observed reduction in mean speeds from 15.6 (sd = 4.2) knots in 2007 to 13.8 (sd = 3.0) knots in 2013 for ships transiting the major shipping route in the eastern Mediterranean. Based on general observed relationships between speed and noise for vessels with fixed pitch propellers, we estimated that slow steaming in the last five years has likely reduced the overall broadband acoustic footprint from these ships by over 50%. There is still a lack of data on noise levels from individual ships and how these relate to different factors such as loading and trim and also a need for noise measurements from new propeller design concepts that offer improvement in fuel efficiency through reduced cavitation. Ongoing research on these issues should help develop further practical and economic quieting technologies in addition to measures already identified in the IMO guidelines. © Journal of Ocean Technology 2014.


Ryan C.,Kilrush Co. | Ryan C.,Mayo Institute of Technology, Galway | Ryan C.,Marine Conservation Research International | Craig D.,Kilrush Co. | And 5 more authors.
Journal of Cetacean Research and Management | Year: 2014

The waters surrounding Cape Verde comprise one of two known breeding grounds for humpback whales in the North Atlantic. The population remains very small and has apparently failed to recover since the cessation of whaling there. During the breeding seasons of 2011 and 2012, sighting surveys were carried out for humpback whales off Boa Vista, the easternmost island of the Cape Verde Island archipelago. The distribution and relative abundance of humpback whales and mother-calf pairs was investigated by plotting effort-corrected sightings using a 2km2 grid-square. The study area, a 206km2region from the coastline up to 8km offshore, covered the western half of Boa Vista where whales have previously been regularly recorded. Following 1,954km of search effort, 117 sightings of humpback whales were made. An encounter rate of 0.11 whales per km was recorded for both years. It is hoped that these data may assist in implementing conservation measures to protect humpback whales and the habitat of Baia Sal Rei, which appears to be the single most important bay for winter breeding, calving and nursing humpback whales in the eastern North Atlantic.


Cucknell A.-C.,Marine Conservation Research International | Frantzis A.,Pelagos Cetacean Research Institute | Boisseau O.,Marine Conservation Research International | Romagosa M.,Marine Conservation Research International | And 7 more authors.
Marine Biodiversity Records | Year: 2016

Results are presented from the first systematic visual and acoustic line-transect survey for harbour porpoises in the Thracian Sea, northern Aegean Sea. During the vessel survey, undertaken in summer 2013, porpoises were observed on nine occasions and detected acoustically 16 times, with a total of 21 distinct encounters recorded. Harbour porpoises were encountered in three discrete blocks: north of the Island of Thasos, Greece; south and west of the city of Alexandroupolis, Greece; and in Saros Bay, Turkey. Saros Bay exhibited the highest relative acoustic encounter rate of harbour porpoises, and porpoises were observed visually there on two occasions 14 days apart, in small groups, one of which included a mother-calf pair. A comprehensive review of stranding records is also presented. The three areas identified as harbour porpoise habitat in this study coincide with the highest number of recorded stranded animals. This paper is the first to report free-swimming harbour porpoises in the Aegean Sea since 1993, and the first time ever in Turkish Aegean waters. Now that the presence of harbour porpoises has been documented, international cooperation towards long term monitoring and management measures are urgently required in order to conserve this vulnerable population. © 2016 The Author(s).


Renilson M.,Renilson Marine Consulting Pty. Ltd. | Leaper R.,International Fund for Animal Welfare | Boisseau O.,Marine Conservation Research International
RINA, Royal Institution of Naval Architects - International Conference on the Environmentally Friendly Ship, Papers | Year: 2012

Underwater noise pollution from shipping has raised ambient noise levels in the 10-300Hz frequency range throughout the world's oceans. Impacts on marine life include disturbance, stress and the masking of biological sounds used to communicate and find food. Impacts on marine mammals have been of particular concern but many species of fish may also be affected. Concerns over the level of impact have resulted in efforts by many bodies, including the International Maritime Organization, to examine ways to reduce noise. It is now widely acknowledged that reducing underwater noise from shipping is both necessary and feasible. Simple calculations suggest that the noisiest 10% of ships generate the majority of the noise impacts and that the dominant source of noise is associated with propeller cavitation. We examine ways in which noise may be reduced while still optimising efficiency and conclude that it may be possible to quieten the noisiest vessels through measures that also improve efficiency. To most effectively combine efficiency and noise reduction measures an improved data set of full scale noise measurements of ships under operating conditions is required. We recommend a programme of measurements designed to contribute to a better understanding of how different factors contribute to noise output and how improved propeller design and wake flow related to energy saving measures may also reduce noise. © 2012: The Royal Institution of Naval Architects.


Cucknell A.-C.,Marine Conservation Research International | Boisseau O.,Marine Conservation Research International | Leaper R.,International Fund for Animal Welfare | Mclanaghan R.,Marine Conservation Research International | Moscrop A.,Marine Conservation Research International
Journal of the Marine Biological Association of the United Kingdom | Year: 2016

An area in the central North Sea was surveyed in November 2011 in order to estimate the abundance and density of harbour porpoises (Phocoena phocoena). A total of 2833 km of pre-determined trackline were acoustically surveyed, of which 28% included visual effort. The poor sighting conditions during the survey limited visual effort and demonstrated the advantage of using acoustic techniques for studying harbour porpoise in winter months. Absolute abundance and density estimates were calculated from acoustic encounter rates using estimates of probability of detection and mean group size. The density of harbour porpoises in the west of the survey area was almost double that in the east, with UK waters to the south-west of the Dogger Bank having the highest density of the area surveyed. The overall acoustic encounter rate was higher than most other surveys in the North Sea. The mean density across the survey area of 0.63 (95% CI 0.27–1.52) individuals km−2 and distribution of porpoises was similar to that documented in the summer suggesting that high abundance of harbour porpoises in the west of the North Sea is not confined to summer months. This information is particularly relevant given plans for the construction of a large offshore wind farm on the UK section of the Dogger Bank; the resulting impacts, including acoustic disturbance from pile driving, will potentially affect substantial numbers of harbour porpoises. Copyright © Marine Biological Association of the United Kingdom 2016


Romagosa M.,Marine Conservation Research International | Boisseau O.,Marine Conservation Research International | Cucknell A.-C.,Marine Conservation Research International | Moscrop A.,Marine Conservation Research International | McLanaghan R.,Marine Conservation Research International
Journal of the Acoustical Society of America | Year: 2015

Sei whale calls have been documented on very few occasions and never in the Azores Archipelago, an area transited by this species during their migration to northern latitudes in spring and early summer. Using a combination of video range tracking (VRT) and acoustic methods, vocalizations are described from an encounter with two sei whales in April 2012 off Pico Island, Azores. Recordings analyzed post-survey revealed 53 low frequency downsweep calls with average maximum frequencies of 100 Hz [standard deviation (SD = 14 Hz)] down to 37 Hz (SD = 8 Hz) over 1.21 s (SD = 0.33 s). Apparent source levels of 177 dB (SD = 5 dB) root-mean-square (rms) re 1 μPa were recorded. Vocalizations were attributed to the pair of sei whales encountered using a combination of the VRT data and differences in arrival time of calls at the hydrophones. These calls are similar to those reported from sei whales off New England and similar to those recorded off Hawaii. The growing body of acoustic data on sei whale vocalizations may contribute to the understanding of this species' distribution and population identity; key information is needed to guide future conservation efforts for this species. © 2015 Acoustical Society of America.


PubMed | Marine Conservation Research International
Type: Journal Article | Journal: The Journal of the Acoustical Society of America | Year: 2015

Sei whale calls have been documented on very few occasions and never in the Azores Archipelago, an area transited by this species during their migration to northern latitudes in spring and early summer. Using a combination of video range tracking (VRT) and acoustic methods, vocalizations are described from an encounter with two sei whales in April 2012 off Pico Island, Azores. Recordings analyzed post-survey revealed 53 low frequency downsweep calls with average maximum frequencies of 100Hz [standard deviation (SD=14Hz)] down to 37Hz (SD=8Hz) over 1.21s (SD=0.33s). Apparent source levels of 177dB (SD=5dB) root-mean-square (rms) re 1Pa were recorded. Vocalizations were attributed to the pair of sei whales encountered using a combination of the VRT data and differences in arrival time of calls at the hydrophones. These calls are similar to those reported from sei whales off New England and similar to those recorded off Hawaii. The growing body of acoustic data on sei whale vocalizations may contribute to the understanding of this species distribution and population identity; key information is needed to guide future conservation efforts for this species.

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