scholarly journals Acoustic Monitoring of a Bottlenose Dolphin (Tursiops truncatus) Population: Trends in Presence and Foraging beyond the Limits of the Lower River Shannon SAC

2021 ◽  
Vol 9 (6) ◽  
pp. 650
Author(s):  
Rachel Charish ◽  
Simon Berrow ◽  
Joanne O’Brien
Keyword(s):  
Bottlenose Dolphin ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Environmental Predictors ◽  
Discrete Population ◽  
A Site ◽  
Glm Modelling ◽  
Important Habitat ◽  
Modelling Approach

The Shannon dolphins are a population of bottlenose dolphins resident year round within the Lower River Shannon SAC, Ireland, which has been designated to protect this relatively small, genetically discrete population. Although trends in habitat use and foraging have been studied within the estuary, little is known about the movements of the Shannon dolphins outside the boundaries of the SAC, and whether any other foraging hotspots exist for this population outside of the estuary. The purpose of this study was to explore the presence and foraging behavior of these dolphins in adjacent waters located 20–30 km to the southwest of the Lower River Shannon SAC. Static acoustic monitoring was carried out with C-PODs deployed in Ballyheigue Bay, Brandon Bay, and around the Maharees between May and November 2013. A GEE-GLM modelling approach was then used to analyze potential significant environmental predictors of presence and foraging by bottlenose dolphins at these sites. Brandon Bay was found to be a site of particular importance for the Shannon population, where dolphins were present on 92% of days monitored and foraging occurring on 20% of all monitored hours. The results of this study indicate that Brandon Bay is a potentially important habitat for the Shannon dolphins and further support designation of this site as a candidate SAC. However, long-term acoustic monitoring should be conducted at all sites to identify relative use of the areas at year-round and inter-annual scales.

Inshore and offshore bottlenose dolphin (Tursiops truncatus) communities distinguished by association patterns near Grand Bahama Island, Bahamas

1999 ◽  
Vol 77 (4) ◽  
pp. 581-592 ◽  
Author(s):  
Kelly A Rossbach ◽  
Denise L Herzing
Keyword(s):  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
Social Groups ◽  
Foraging Strategies ◽  
Association Patterns ◽  
Simple Ratio ◽  
Water Depths

Little is known about the behavior of offshore dolphin populations. Our purpose was to distinguish and describe stable social groups of bottlenose dolphins (Tursiops truncatus) between inshore and offshore West End, Grand Bahama Island (26°42'N, 79°00'W). Photoidentification was conducted from May to September, 1994 to 1996. A simple ratio index described association patterns between dolphins. Multidimensional scaling of association indices (n = 1711 dolphin pairs) distinguished two dolphin communities consisting of 28 dolphins (19 of known sex) found inshore and 15 dolphins (12 of known sex) found greater than or equal to 27 km offshore. Eight of the 15 offshore dolphins were opportunistically photographed in the same region between 1986 and 1990. The two communities were found at different water depths (Mann-Whitney U test, p < 0.01), over distinct bottom types (Kruskal-Wallis test, p < 0.01), and used different bottom-foraging strategies. Long-term site fidelity of up to 10 years and repeated dolphin associations of up to 8 years occurred greater than or equal to 27 km from shore. Dolphins sighted greater than or equal to 15 times averaged 48 associates (SD = 11, n = 28). A dolphin's closest associate was of the same gender 74% of the time. This study is the first to report long-term site fidelity and association patterns of bottlenose dolphins found far from shore.

Effects of pingers on the behaviour of bottlenose dolphins

2007 ◽  
Vol 87 (1) ◽  
pp. 129-133 ◽  
Author(s):  
Ruth H. Leeney ◽  
Simon Berrow ◽  
David McGrath ◽  
Joanne O'Brien ◽  
Ronan Cosgrove ◽  
...  
Keyword(s):  
Bottlenose Dolphin ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Controlled Trials ◽  
Detection Rates ◽  
And Control ◽  
Monitoring Devices

Trials were carried out in the Shannon estuary, Ireland, to test the effects of continuous (CPs) and responsive pingers (RPs) on bottlenose dolphin behaviour. In controlled trials, active and control pingers were deployed on fixed moorings, with T-PODs—acoustic monitoring devices to detect cetacean activity. In a separate trial, pingers were deployed from a moving boat which actively located dolphin groups in the estuary, and dolphin behaviour was recorded. In the static trials, overall detection rates of dolphin vocalizations on the T-POD were significantly lower in the presence of active CPs, but this was not the case for RPs. Mean inter-click interval values were longer for click trains produced in the presence of inactive RPs than for active RPs, active or inactive CPs. In boat-based trials, both active CPs and RPs appeared to affect bottlenose dolphin behaviour, whereby dolphins immediately left the area at speed and in a highly directional manner, involving frequent leaps.

scholarly journals Introducing NMMF WAMS, an open-source PAMGuard plug-in, and some pilot data for its use as a welfare acoustic monitoring system

2020 ◽  
Author(s):  
Brittany L Jones ◽  
Michael Oswald ◽  
Samantha Tufano ◽  
Mark Baird ◽  
Sam H. Ridgway
Keyword(s):  
Social Interactions ◽  
Open Source ◽  
Monitoring System ◽  
Marine Mammal ◽  
Early Identification ◽  
Marine Mammals ◽  
False Positive Rate ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Discrete Population

Abstract BackgroundThe National Marine Mammal Foundation presents a new veterinary and animal welfare monitoring tool, WAMS (i.e., Welfare Acoustic Monitoring System) for open-source use in PAMGuard. While the use of passive acoustic monitoring systems has been invaluable in wild conservation efforts, vocal behavior is a vastly underutilized welfare biomarker for both terrestrial and aquatic species in zoos and aquaria. We describe one successful use for WAMS at the Navy Marine Mammal Program for monitoring a discrete population of dolphins’ acoustic behavior. By constantly recording both five minute and hourly counts of acoustic detections and providing an automated comparison to historical data, WAMS can alert us to rare instances of high vocal rates relative to their typical output. Having a validated acoustic indicator for events such as agnostic social interactions and/or an instance of distress in bottlenose dolphins provides a unique opportunity for acoustic monitoring to be used as a tool for the early identification and possible prevention of rare and unexpected instances of an illness or injury.ResultsWe identified a high success rate (82%) and low false positive rate (1%) for WAMS identification of whistle occurrence. Further, we identified time and money saving applications for use in conservation settings such as marine mammal mitigation surveys and long-term hydrophone deployments. When running in real-time, WAMS used in conjunction with other PAMGuard features saved almost 6.5 days in manual labor for every month processing data (almost 78.5 work days a year). ConclusionsWe propose that this tool could be considered for implementation at any facility that houses marine mammals and wishes to include acoustic monitoring into their preventative healthcare plans. Early identification of atypical social interactions and/or distress calls in both aquatic and terrestrial species can lead to early intervention, better management of social groupings, and better overall health and welfare for all animals.

Using lake sediment P records to estimate internal and external P loading and historic long-term lake water mean TP: a case study using published records from Søbygaard Sø, Denmark.

2021 ◽  
Author(s):  
John Boyle ◽  
Maddy Moyle
Keyword(s):  
Lake Sediment ◽  
Lake Water ◽  
Balance Model ◽  
Sediment Record ◽  
Internal P Loading ◽  
A Site ◽  
External P Loading ◽  
Modelling Approach

&lt;p&gt;Lake sediment records offer the opportunity to quantify past changes in catchment P exports, information essential if we are to understand the long-term drivers that control P cycling. However, the interpretation of such records generally depends on the assumption that sediment P concentration profiles remain intact after burial. This assumption appears to be in conflict with the phenomenon of internal P loading, whereby P is exported from sediment to the water column. Here we apply a simple long-term mass balance model to published sediment record data from S&amp;#248;bygaard, a site that has an exceptionally high internal P loading, and an exceptionally well-studied sediment P record (S&amp;#248;ndergaard and Jeppesen, 2019). Repeat cores collected from 1985 to 2004 constrain the temporal evolution of a sediment P peak arising from past sewage inflows, providing a critical test of our modelling approach. We find that useful sediment inference of long-term mean lake water TP is preserved in the sediment record, and predict also useful inference of long-term mean external P loading. Limitation on temporal resolution of the records is examined.&lt;/p&gt;

scholarly journals Long-Term Demographic and Spatio-Temporal Trends of Indo-Pacific Bottlenose Dolphin (Tursiops aduncus) Bycatch in Bather Protection Nets off KwaZulu-Natal, South Africa

2020 ◽  
Vol 7 ◽  
Author(s):  
Stephanie Plön ◽  
Christine Erbe ◽  
Sabine Wintner
Keyword(s):  
South Africa ◽  
Bottlenose Dolphin ◽  
Bottlenose Dolphins ◽  
Temporal Trends ◽  
Long Term Effects ◽  
Annual Fluctuation ◽  
Tursiops Aduncus ◽  
Kwazulu Natal ◽  
The Impact

Bather protection nets have been in place off the coast of KwaZulu-Natal (KZN), South Africa, since the 1950’s. Besides sharks, they also catch a number of other marine vertebrates, including dolphins, the majority of which are Indo-Pacific bottlenose dolphins Tursiops aduncus. Previous analyses of dolphin bycatch in the nets indicated the potential impacts on the local populations, but a lack of information on population structure has to-date hindered a more detailed assessment. A recent re-assessment of the status and population delineations of T. aduncus off South Africa prompted a re-examination of demographic, spatial, and temporal patterns of its catches in bather protection nets over a 36-year period (January 1980 to December 2015). In total, 1169 dolphins were caught, including a slightly greater number of females and juveniles than other sex-classes, raising concern about the potential long-term effects on population demographics. More dolphins were caught off the North than the South coast. Temporal trends indicate that the bycatch during June and July every year (peak Sardine Run period) as a percentage of overall dolphin bycatch has been steadily decreasing from 39.8% in 1980 to 13% in 2015. A large inter-annual fluctuation can be seen, probably as a result of the inter-annual intensity of the Sardine Run. Although our results do not indicate a long-term decline of the individual populations as previously predicted, revised abundance estimates and data on the demographics and movement patterns of the animals are urgently required to accurately assess the impact of bycatch on the Indo-Pacific bottlenose dolphin populations off KZN and to advise conservation and management decisions going forward.

scholarly journals Passive acoustic monitoring of the bottlenose dolphin Tursiops truncatus to determine continuous presence in Ensenada de La Paz, Mexico

2021 ◽  
Vol 55 (3) ◽  
pp. 238
Author(s):  
Marco FW Gauger ◽  
Javier Caraveo-Patiño ◽  
Eduardo Romero-Vivas
Keyword(s):  
Bottlenose Dolphin ◽  
Tursiops Truncatus ◽  
Gulf Of California ◽  
Bottlenose Dolphins ◽  
Acoustic Monitoring ◽  
Passive Acoustic Monitoring ◽  
La Paz ◽  
Custom Made ◽  
Continuous Presence ◽  
Passive Acoustic

Bottlenose dolphins (Tursiops truncatus) are ecosystem sentinels. In the Gulf of California, Mexico, they are found in areas that overlap with human activities, as in the case of the Ensenada de La Paz lagoon. A custom-made recorder -moored at medium depth (2.0 m) in the entrance to the lagoon- recorded acoustic data from June to November 2017 (8 deployments; 293 h). Whistles -an indicative of bottlenose dolphin presences- were pooled over time to acquire acoustic encounters, which were analysed to infer continuity of animal presence and test for statistically significant differences between deployments, day and night, and hours. Whistles were recorded during all deployments and evidenced night-time presence of bottlenose dolphins in the lagoon. Significant differences of acoustic encounters were observed between ‘Jun-Jul’ and ‘Sep-Nov’. Acoustic encounters were higher at night but were not different at an hourly level. Acoustical data proved the continuous presence of bottlenose dolphins, highlighting the importance of the Ensenada de La Paz for their population. This initial study highlights the usefulness of long-term passive acoustic monitoring to inform stake holders involved in management and conservation plans.

Investigation of a New Approach to Predict Water Quality Extremes with a Case Study of Chemical Determinands in Stream Water

1991 ◽  
Vol 24 (6) ◽  
pp. 25-33
Author(s):  
A. J. Jakeman ◽  
P. G. Whitehead ◽  
A. Robson ◽  
J. A. Taylor ◽  
J. Bai
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Probability Distributions ◽  
Management Strategies ◽  
Hybrid Modelling ◽  
Trend Model ◽  
Environmental Extremes ◽  
Modelling Approach

The paper illustrates analysis of the assumptions of the statistical component of a hybrid modelling approach for predicting environmental extremes. This shows how to assess the applicability of the approach to water quality problems. The analysis involves data on stream acidity from the Birkenes catchment in Norway. The modelling approach is hybrid in that it uses: (1) a deterministic or process-based description to simulate (non-stationary) long term trend values of environmental variables, and (2) probability distributions which are superimposed on the trend values to characterise the frequency of shorter term concentrations. This permits assessment of management strategies and of sensitivity to climate variables by adjusting the values of major forcing variables in the trend model. Knowledge of the variability about the trend is provided by: (a) identification of an appropriate parametric form of the probability density function (pdf) of the environmental attribute (e.g. stream acidity variables) whose extremes are of interest, and (b) estimation of pdf parameters using the output of the trend model.

scholarly journals Activity Budget Comparisons Using Long-Term Observations of a Group of Bottlenose Dolphins (Tursiops truncatus) under Human Care: Implications for Animal Welfare

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2107
Author(s):  
Tim Huettner ◽  
Sandra Dollhaeupl ◽  
Ralph Simon ◽  
Katrin Baumgartner ◽  
Lorenzo von Fersen
Keyword(s):  
Bottlenose Dolphins ◽  
Activity Budget ◽  
Behavioral Differences ◽  
Training Performance ◽  
Behavioral Observations ◽  
Daily Training ◽  
Human Care ◽  
Over Time ◽  
The Welfare State

Zoos and aquaria must provide optimal husbandry conditions and the highest welfare standards for their animals. How the welfare state of an animal or a group of animals can be precisely assessed is currently under debate, and new approaches are necessary to reliably evaluate changes in welfare. One particular measure that is easily applicable is behavioral observations. However, for dolphins and other cetaceans under human care, reliable behavior-based measures are rare. Using long-term observations of a group of bottlenose dolphins, we investigate how their activity budgets and different behaviors changed over time and are impacted by construction noise. Additionally, we investigate whether behavioral differences are also reflected in changes in the dolphins’ performance during daily training sessions. Our results show that construction noise significantly alters the dolphins’ behavior. Play behavior decreases during construction periods; most importantly, the frequency of fast swimming activities significantly increased, and at the same time, a decrease in training performance is found. Additionally, inter- and intraindividual behavioral differences are attributed to factors, such as age or weaning. Significant changes in a dolphin’s activity budget can also pose potential welfare concerns. Thus, this study highlights the importance of regularly assessing and analyzing the behavior of dolphins under human care. Behavioral observations are essential welfare indicators and can—when complemented with other measures, such as assessment of training performance—provide zoo staff with important information about each individual’s state of welfare.

scholarly journals Foraging Behavior of Bottlenose Dolphins in the Shannon Estuary, Ireland as Determined through Static Acoustic Monitoring

2021 ◽  
Vol 9 (3) ◽  
pp. 275
Author(s):  
Mathijs Carmen ◽  
Simon D. Berrow ◽  
Joanne M. O’Brien
Keyword(s):  
Foraging Behavior ◽  
Bottlenose Dolphins ◽  
Industrial Area ◽  
Acoustic Monitoring ◽  
Habitats Directive ◽  
Foraging Area ◽  
Special Area ◽  
High Conservation ◽  
Eu Habitats Directive ◽  
The Eu

The Shannon Estuary in Ireland is home to a resident population of bottlenose dolphins (Tursiops truncatus) and is designated as a Special Area of Conservation under the EU Habitats Directive. It is an important industrial area, with numerous deep-water berths for shipping. Despite its high conservation value, there are few published studies on habitat use or foraging behavior of the Shannon dolphins throughout the year. The present study assessed the year-round presence and foraging activity of bottlenose dolphins at different locations in the middle and inner estuary using static acoustic monitoring. Dolphin presence was found to decrease with increased distance from the estuary mouth, i.e., where the estuary meets the Atlantic Ocean, while at the same time, foraging was found to be considerably higher in the upriver areas, suggesting the inner estuary was an important foraging area. Model predictions for seasonal, tidal and diel foraging were highly variable across locations, indicating that changes in dolphin behavior occurred over relatively small geographical scales. These results indicate that conservation efforts should consider the Shannon Estuary as a dynamic aggregation of habitats and future development initiatives should attempt to mitigate disturbance to the dolphins during important foraging periods on seasonal and diel scales.

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