Monitoring important coastal sites for bottlenose dolphin in Cardigan Bay, UK

2009 ◽  
Vol 89 (5) ◽  
pp. 1033-1043 ◽  
Author(s):  
Chris Pierpoint ◽  
Liz Allan ◽  
Holly Arnold ◽  
Peter Evans ◽  
Sarah Perry ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Coastal Zone Management ◽  
Site Occupancy ◽  
Cost Effective ◽  
County Council ◽  
Monitoring Site ◽  
Positive Trend ◽  
Site Use ◽  
Boat Traffic

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.

scholarly journals The Protection of Animals During Warfare

AJIL Unbound ◽  
2017 ◽  
Vol 111 ◽  
pp. 272-276
Author(s):  
Jérôme de Hemptinne
Keyword(s):  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Rapid Rate ◽  
Human Beings ◽  
Armed Groups ◽  
Military Operations ◽  
Protected Species ◽  
California Sea Lions ◽  
Animal Products ◽  
Sea Lions

In times of war, the first instinct is to relieve the suffering of human beings. Environmental and animal interests are always pushed into the background. However, warfare strongly affects natural resources, including animals, which makes animal issues a matter of great concern. Certain species have been vanishing at a rapid rate because of wars, often with disastrous effects on the food chain and on the ecological balance. Indeed, belligerents rarely take into account the adverse consequences of their military operations on animals. They even take advantage of the chaotic circumstances of war in order to poach protected species and to engage in the trafficking of expensive animal products. While generating billions of dollars each year, such poaching and trafficking allows armed groups to grow and to reinforce their authority over disputed territory. States have also trained, and continue to train, certain animals—principally marine mammals such as bottlenose dolphins and California sea lions—to perform military tasks, like ship and harbor protection, or mine detection and clearance. Millions of horses, mules, donkeys, camels, dogs, and birds are obliged to serve on various fronts (transport, logistics, or communications) and become particularly vulnerable targets.

scholarly journals Cetacean Research and Citizen Science in Kenya

2021 ◽  
Vol 8 ◽  
Author(s):  
Michael Gilbert Mwango’mbe ◽  
Jane Spilsbury ◽  
Steve Trott ◽  
Judith Nyunja ◽  
Nina Wambiji ◽  
...  
Keyword(s):  
Citizen Science ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Conservation Strategies ◽  
Science Data ◽  
Pilot Whale ◽  
Area Of Interest ◽  
Mammal Conservation ◽  
Kenyan Coast

In 2011, several non-governmental and government agencies established the Kenya Marine Mammal Network (KMMN) to provide a platform for the consistent collection of data on marine mammals along the Kenyan coast, identify areas of importance and engage marine users and the general public in marine mammal conservation. Prior to the KMMN, relatively little was known about marine mammals in Kenya, limiting conservation strategies. The KMMN collects data nationwide through dedicated surveys, opportunistic sightings and participative citizen science, currently involving more than 100 contributors. This paper reviews data on sightings and strandings for small cetaceans in Kenya collated by the KMMN. From 2011 to 2019, 792 records of 11 species of small cetaceans were documented. The most frequently reported inshore species were the Indo-Pacific bottlenose dolphin and Indian Ocean humpback dolphin. Offshore species, included killer whales, short-finned pilot whale and long-snouted spinner dolphin. Indo-Pacific bottlenose dolphins, long-snouted spinner dolphins, striped dolphins and Risso’s dolphins were recorded through stranding reports. The efforts of the KMMN were disseminated through international meetings (International Whaling Commission, World Marine Mammal Conference), national status reports, outreach and social media. Data has also supported the identification of three IUCN Important Marine Mammal Areas and one Area of Interest in Kenya. Further research is needed to improve estimates of cetacean abundance and distribution, particularly in unstudied coastal areas, and to assess the extent of anthropogenic threats associated with fisheries, coastal and port development, seismic exercises and unregulated tourism. The expansion of the network should benefit from the participation of remote coastal fishing communities, government research agencies, tourism and seismic operations, among others. The KMMN demonstrated the value of dedicated and citizen science data to enhance marine mammal conservation strategies to boost awareness and eco-tourism and to bring the public and science closer together, promoting research and effective conservation efforts.

scholarly journals Spatial and temporal variation in the occurrence of bottlenose dolphins in the Chesapeake Bay, USA, using citizen science sighting data

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251637
Author(s):  
Lauren Kelly Rodriguez ◽  
Amber D. Fandel ◽  
Benjamin R. Colbert ◽  
Jamie C. Testa ◽  
Helen Bailey
Keyword(s):  
Chesapeake Bay ◽  
Citizen Science ◽  
Marine Mammals ◽  
Generalized Additive Models ◽  
Bottlenose Dolphins ◽  
Temporal Distribution ◽  
Additive Models ◽  
Spatial And Temporal Variation ◽  
Estuarine System ◽  
Predictive Tool

Bottlenose dolphins (Tursiops truncatus) are migratory marine mammals that live in both open-ocean and coastal habitats. Although widely studied, little is known about their occurrence patterns in the highly urbanized estuary of the Chesapeake Bay, USA. The goal of this study was to establish the spatial and temporal distribution of bottlenose dolphins throughout this large estuarine system and use statistical modeling techniques to determine how their distribution relates to environmental factors. Three years (April-October 2017–2019) of dolphin sighting reports from a citizen-science database, Chesapeake DolphinWatch, were analyzed. The dolphins had a distinct temporal pattern, most commonly sighted during summer months, peaking in July. This pattern of observed occurrence was confirmed with systematic, passive acoustic detections of dolphin echolocation clicks from local hydrophones. Using spatially-exclusive Generalized Additive Models (GAM), dolphin presence was found to be significantly correlated to spring tidal phase, warm water temperature (24–30°C), and salinities ranging from 6–22 PPT. We were also able to use these GAMs to predict dolphin occurrence in the Bay. These predictions were statistically correlated to the actual number of dolphin sighting reported to Chesapeake DolphinWatch during that time. These models for dolphin presence can be implemented as a predictive tool for species occurrence and inform management of this protected species within the Chesapeake Bay.

scholarly journals Age determination of common bottlenose dolphins (Tursiops truncatus) using dental radiography pulp:tooth area ratio measurements

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242273
Author(s):  
Jean M. Herrman ◽  
Jeanine S. Morey ◽  
Ryan Takeshita ◽  
Sylvain De Guise ◽  
Randall S. Wells ◽  
...  
Keyword(s):  
Life Histories ◽  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Age Determination ◽  
Area Ratio ◽  
Dental Radiography ◽  
Ratio Method ◽  
Data Sets ◽  
Photo Identification ◽  
Development And Validation

Age is an important parameter to better understand wildlife populations, and is especially relevant for interpreting data for fecundity, health, and survival assessments. Estimating ages for marine mammals presents a particular challenge due to the environment they inhabit: accessibility is limited and, when temporarily restrained for assessment, the window of opportunity for data collection is relatively short. For wild dolphins, researchers have described a variety of age-determination techniques, but the gold-standard relies upon photo-identification to establish individual observational life histories from birth. However, there are few populations with such long-term data sets, therefore alternative techniques for age estimation are required for individual animals without a known birth period. While there are a variety of methods to estimate ages, each involves some combination of drawbacks, including a lack of precision across all ages, weeks-to-months of analysis time, logistical concerns for field applications, and/or novel techniques still in early development and validation. Here, we describe a non-invasive field technique to determine the age of small cetaceans using periapical dental radiography and subsequent measurement of pulp:tooth area ratios. The technique has been successfully applied for bottlenose dolphins briefly restrained during capture-release heath assessments in various locations in the Gulf of Mexico. Based on our comparisons of dental radiography data to life history ages, the pulp:tooth area ratio method can reliably provide same-day estimates for ages of dolphins up to about 10 years old.

Monitoring site occupancy for American mink in its native range

2011 ◽  
Vol 76 (4) ◽  
pp. 824-831 ◽  
Author(s):  
Robert L. Schooley ◽  
Lisa A. Cotner ◽  
Adam A. Ahlers ◽  
Edward J. Heske ◽  
Jeffrey M. Levengood
Keyword(s):  
American Mink ◽  
Site Occupancy ◽  
Monitoring Site ◽  
Native Range

scholarly journals Determining multi-species site use outside the protected areas of the Maasai Mara, Kenya, using false positive site-occupancy modelling

Oryx ◽  
2018 ◽  
Vol 54 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Emily K. Madsen ◽  
Femke Broekhuis
Keyword(s):  
Protected Areas ◽  
False Positive ◽  
Site Occupancy ◽  
Occupancy Modelling ◽  
Term Survival ◽  
Acinonyx Jubatus ◽  
Human Presence ◽  
Site Use ◽  
Positive Site ◽  
Wild Dogs

AbstractAlthough protected areas are the basis for many conservation efforts they are rarely of an adequate size for the long-term survival of populations of large, wide-roaming mammals. In the Maasai Mara, Kenya, communally owned wildlife conservancies have been developed to expand the area available for wildlife. As these continue to develop it is important to ensure that the areas chosen are beneficial to wildlife. Using presence data for cheetahs Acinonyx jubatus, elephants Loxodonta africana, spotted hyaenas Crocuta crocuta, leopards Panthera pardus, lions Panthera leo and wild dogs Lycaon pictus, collected through interviews with 648 people living outside protected areas, we identify key wildlife areas using false positive site-occupancy modelling. The probabilities of site use were first determined per species based on habitat, distance to protected area, human presence and rivers, and these probabilities were then combined to create a map to highlight key wildlife areas. All species, except hyaenas, preferred sites closer to the protected areas but site use varied by species depending on habitat type. All six species avoided human presence. Leopards, elephants, lions and wild dogs preferred sites closer to rivers. The resulting combined map highlights areas that could potentially benefit from conservation efforts, including the expansion of wildlife areas, and areas where human development, such as a newly tarmacked road, could have an impact on wildlife.

Performance of bycatch reduction devices varies for chondrichthyan, reptile, and cetacean mitigation in demersal fish trawls: assimilating subsurface interactions and unaccounted mortality

2016 ◽  
Vol 74 (1) ◽  
pp. 343-358 ◽  
Author(s):  
Corey B. Wakefield ◽  
Julia Santana-Garcon ◽  
Stacey R. Dorman ◽  
Stuart Blight ◽  
Ainslie Denham ◽  
...  
Keyword(s):  
Electronic Monitoring ◽  
Bottlenose Dolphins ◽  
Cost Effective ◽  
Demersal Fish ◽  
Mitigation Strategies ◽  
Trawl Fishery ◽  
Bycatch Reduction ◽  
Cost Effective Method ◽  
Species Specific

To improve bycatch mitigation of chondrichthyans, reptiles and cetaceans for a tropical demersal fish-trawl fishery, species-specific responses to bycatch reduction devices (BRDs) were investigated using both in situ subsurface and onboard observations. There are few, if any, studies that have determined mitigation performances of BRDs from subsurface interactions for these species, as most are rarely encountered and thus require substantial levels of observer coverage for robust assessments. This study combined in-net and onboard (774 day trawls and 1320 day trawl hours of subsurface observer coverage) electronic monitoring on all fish-trawl vessels (n = 3) to compare bycatch mitigation performances among nine megafauna groups, based on escape rates and interaction durations for three BRDs over 6 months (June to December 2012). Overall, 26.9% of day trawls had no megafauna interactions and 38.3% of the 1826 interactions escaped, with most in rapid time (91.4% in ≤ 5 min). The upward inclined exclusion grid significantly improved the escape proportions for most chondrichthyans by 20–30%. All BRDs were highly effective in reducing reptile (turtles and seasnakes) bycatch, but irrelevant for the few sawfish (n = 13) that readily entangled in the anterior of the net. Cetacean (bottlenose dolphins only) interactions with BRDs were very rare (n = 7) despite high levels of attendance and depredation during trawling. Loss of targeted teleosts through the BRD hatch was rare (1.3% of day trawls). This relatively cost-effective method of electronic monitoring achieved very high levels of subsurface observer coverage (60% of day trawls or 56% of day trawl hours), and provided evidence that the subsurface expulsion of megafauna in poor condition is negligible. Furthermore, this study provides species-specific improvements toward bycatch mitigation strategies for demersal fish trawling.

scholarly journals The diving physiology of bottlenose dolphins (Tursiops truncatus). II. Biomechanics and changes in buoyancy at depth

1999 ◽  
Vol 202 (20) ◽  
pp. 2749-2761 ◽  
Author(s):  
R.C. Skrovan ◽  
T.M. Williams ◽  
P.S. Berry ◽  
P.W. Moore ◽  
R.W. Davis
Keyword(s):  
Tursiops Truncatus ◽  
Marine Mammals ◽  
Bottlenose Dolphins ◽  
Neutral Buoyancy ◽  
Swimming Mode ◽  
Locomotor Patterns ◽  
The Cost ◽  
Physical Changes ◽  
And Behavior ◽  
Limited Oxygen

During diving, marine mammals must balance the conservation of limited oxygen reserves with the metabolic costs of swimming exercise. As a result, energetically efficient modes of locomotion provide an advantage during periods of submergence and will presumably increase in importance as the animals perform progressively longer dives. To determine the effect of a limited oxygen supply on locomotor performance, we compared the kinematics and behavior of swimming and diving bottlenose dolphins. Adult bottlenose dolphins (Tursiops truncatus) were trained to swim horizontally near the water surface or submerged at 5 m and to dive to depths ranging from 12 to 112 m. Swimming kinematics (preferred swimming mode, stroke frequency and duration of glides) were monitored using submersible video cameras (Sony Hi-8) held by SCUBA divers or attached to a pack on the dorsal fin of the animal. Drag and buoyant forces were calculated from patterns of deceleration for horizontally swimming and vertically diving animals. The results showed that dolphins used a variety of swimming gaits that correlated with acceleration. The percentage of time spent gliding during the descent phase of dives increased with depth. Glide distances ranged from 7.1+/−1.9 m for 16 m dives to 43.6+/−7.0 m (means +/− s.e.m.) for 100 m dives. These gliding patterns were attributed to changes in buoyancy associated with lung compression at depth. By incorporating prolonged glide periods, the bottlenose dolphin realized a theoretical 10–21 % energetic savings in the cost of a 100 m dive in comparison with dives based on neutral buoyancy models. Thus, modifying locomotor patterns to account for physical changes with depth appears to be one mechanism that enables diving mammals with limited oxygen stores to extend the duration of a dive.

scholarly journals Dolphin-Watching Boats Affect Whistle Frequency Modulation in Bottlenose Dolphins

2021 ◽  
Vol 8 ◽  
Author(s):  
Betzi Perez-Ortega ◽  
Rebecca Daw ◽  
Brennan Paradee ◽  
Emma Gimbrere ◽  
Laura J. May-Collado
Keyword(s):  
Bottlenose Dolphins ◽  
Emotional States ◽  
National Guidelines ◽  
Bocas Del Toro ◽  
System A ◽  
Potential Association ◽  
Boat Traffic ◽  
A Site ◽  
Signature Whistle ◽  
Dolphin Watching

Bottlenose dolphins’ whistles are key in social communication, conveying information about conspecifics and the environment. Therefore, their study can help to infer habitat use and identify areas of concern due to human activities. Here we studied the whistles of bottlenose dolphins (Tursiops truncatus) in two sites of the archipelago of Bocas del Toro, Panama, that contrast in boat traffic. Almirante Bay is a site dominated by taxi-boats and Dolphin Bay is a major location for boat-based dolphin watching. Recordings were made using bottom-mounted hydrophones and from the research boat using an over-the-side hydrophone and a broadband recording system. A total recording effort time of 1,726 h was analyzed. Our results show significant differences in boat detection between sites, and a higher number of whistles detected per minute in the site with tour-boat traffic. Furthermore, whistle modulation accounted for most of the differences between sites, boat presence, and whistle types. Dolphin whistle modulation is thought to be a potential indicator of emotional states including danger, alertness, and stress. In this study, dolphin signature whistle modulation increased significantly with boat presence in both sites but changes in modulation were greater in Dolphin Bay where tour-boats directly and sometimes aggressively interact with the animals. These results support a potential association between whistle modulation and stress (or alertness). These findings indicate that if tour-boat captains behave more like taxi-boat captains by e.g., reducing the distance of approach and contact time during dolphin interactions, dolphin communication, and emotional state would be less disrupted. These measures are implemented in the national guidelines for whale-watching and are known to tour-boat operators. The key to protecting these dolphins is in finding ways to effectively enforce these operator guidelines.

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