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Results of attempts to tag Atlantic Bottlenosed dolphins, (Tursiops turncatus)

Authors:
A. Blair Irvine at Independent Researcher
A. Blair Irvine
  • Independent Researcher
Randall Wells at Chicago Zoological Society
Randall Wells
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Abstract

The first pilot program for tagging Atlantic Bottlenosed dolphind was conducted on the west coast of Florida. Freeze branding and visible plastic tags marked the animals. Results suggest presence of distinct herds in the study area, moving in consistent patterns, apparently dependent on the tides. Some evidence for sexual segregation and sub-group cohesion were noted.
1972 Irvine and Wells Pilot Tagging Proje
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1972 Irvine and Wells Pilot Tagging Proje
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Content uploaded by A. Blair Irvine
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All content in this area was uploaded by A. Blair Irvine on Jun 17, 2015
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... The longest-running field studies have been those in Sarasota Bay on the west coast of Florida in the U.S. and in Shark Bay in western Australia. The Sarasota Bay study on Tursiops truncatus started in 1970 (Irvine and Wells, 1972;Scott et al., 1990;Wells, 1991) and the Shark Bay study on Tursiops aduncus began in 1982 (Connor and Smolker, 1985). Taken together, these two long-term studies on the social structure of wild bottlenose dolphin populations allow us to contrast male mating strategies and reproductive exchange in two very discrete coastal areas. ...
... The SBDC is one of a mosaic of adjacent communities along Florida's central west coast (Irvine and Wells, 1972;Wells et al., 1980;Irvine et al., 1981;Wells, 1986;Wells et al., 1987;Sellas et al., 2005;Fazioli et al., 2006;Urian et al., 2009;Bassos-Hull et al., 2013) and although these communities have discrete home ranges built around resident females, their calves and associates, low rates of immigration and emigration have been documented. Males in particular seem to move between these communities and to have larger home ranges than the females based on patterns of social affiliation and long-term site fidelity (Urian et al., 2009). ...
Paternity patterns in a long-term resident bottlenose dolphin community
Article
Full-text available
  • Feb 2023
Genetic analyses, initiated in 1984, have played a major role in our understanding of the structure and social relationships of the long-term resident community of common bottlenose dolphins (Tursiops truncatus) in Sarasota Bay, Florida (SBDC). One component of our ongoing study of the community’s social system involves using blood samples from periodic catch-and-release sampling for life history and health assessment studies, as well as skin from biopsy dart sampling studies and strandings, to investigate paternity and mating strategies in this community. These analyses, covering a span of four generations of calves, were originally based on chromosomes and protein electrophoresis, but with the advent of microsatellite DNA technology, the latter has become our analysis of choice. We have performed paternity analyses on 204 known mother-calf pairs. For 151 of the calves (74%), sires were identified within the SBDC, but for the remaining 26% of the calves all sampled males associated with the community were excluded and it is likely that a substantial contribution of paternity to the SBDC comes from outside the community. Of the SBDC males, only 52 males of the more than 200 potential sires were sires. The age of sires at time of conception of a calf ranged from 10 to 43 years, averaging 24 years old. These males have sired 1-7 calves during a documented period of reproductive tenure of as much as 24 years (average = 21.4 years). Four males have sired 6-7 calves each, these males siring calves in the community for more than 20 years. Another 19 males have each sired 3-5 calves and the remaining 30 males were identified as sires of 1-2 calves. Paired males sired 75% of the calves while 25% of the calves were sired by unpaired males. Females with multiple offspring generally had multiple sires for these offspring. These paternity analyses support the hypothesis that a major avenue of gene flow in the SBDC is through the males given their greater ranges, with occasional exchange via visits from males from other areas, as well as the occasional brief movements of females from outside the community range into the community.
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... Regarding identifications, we had the unique capacity of having high confidence in our matches of lowto-non distinctive fins given the images used came from the longterm database of known Sarasota Bay resident dolphins (Wells et al., 1987;Wells, 2014). After beginning with tagging in 1970 (Irvine and Wells, 1972), the SDRP began using photo-ID methods in Sarasota Bay, Florida in the 1970s based on the finding that many individuals had lasting natural markings that could be tracked through time (Wells et al., 1980;Irvine et al., 1981;Wells and Scott, 1990;Wells, 2009;Wells, 2014). Since that time the SDRP has used photo-ID data to document the residency patterns of more than approximately 500 dolphins in the Sarasota Bay region ( Figure 1) and our database has grown to include more than 40,000 encounters of dolphin groups and over 120,000 sightings of individual dolphins. ...
Rise of the Machines: Best Practices and Experimental Evaluation of Computer-Assisted Dorsal Fin Image Matching Systems for Bottlenose Dolphins
Article
Full-text available
  • Apr 2022
Photographic-identification (photo-ID) of bottlenose dolphins using individually distinctive features on the dorsal fin is a well-established and useful tool for tracking individuals; however, this method can be labor-intensive, especially when dealing with large catalogs and/or infrequently surveyed populations. Computer vision algorithms have been developed that can find a fin in an image, characterize the features of the fin, and compare the fin to a catalog of known individuals to generate a ranking of potential matches based on dorsal fin similarity. We examined if and how researchers use computer vision systems in their photo-ID process and developed an experiment to evaluate the performance of the most commonly used, recently developed, systems to date using a long-term photo-ID database of known individuals curated by the Chicago Zoological Society’s Sarasota Dolphin Research Program. Survey results obtained for the “Rise of the machines – Application of automated systems for matching dolphin dorsal fins: current status and future directions” workshop held at the 2019 World Marine Mammal Conference indicated that most researchers still rely on manual methods for comparing unknown dorsal fin images to reference catalogs of known individuals. Experimental evaluation of the finFindR R application, as well as the CurvRank, CurvRank v2, and finFindR implementations in Flukebook suggest that high match rates can be achieved with these systems, with the highest match rates found when only good to excellent quality images of fins with average to high distinctiveness are included in the matching process: for the finFindR R application and the CurvRank and CurvRank v2 algorithms within Flukebook more than 98.92% of correct matches were in the top 50-ranked positions, and more than 91.94% of correct matches were returned in the first ranked position. Our results offer the first comprehensive examination into the performance and accuracy of computer vision algorithms designed to assist with the photo-ID process of bottlenose dolphins and can be used to build trust by researchers hesitant to use these systems. Based on our findings and discussions from the “Rise of the Machines” workshop we provide recommendations for best practices for using computer vision systems for dorsal fin photo-ID.
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... However, further research is necessary to understand the relationships among habitat features, management programs, and habitat use. In the wild, dolphins in waterways near Sarasota Bay, Florida, USA reside in habitats up to 11 m deep [19,20]. Most sightings occur in areas that are less than 2-3 m deep. ...
Habitat characteristics and animal management factors associated with habitat use by bottlenose dolphins in zoological environments
Article
Full-text available
The way an animal uses its habitat can serve as an indicator of habitat appropriateness for the species and individuals. Bottlenose dolphins (Tursiops truncatus and Tursiops aduncus) in accredited zoos and aquariums experience a range of habitat types and management programs that provide opportunities for dolphins to engage in species-appropriate behaviors and potentially influence their individual and group welfare. Data in the present study were collected as part of a larger study titled “Towards understanding the welfare of cetaceans in zoos and aquariums” (colloquially called the Cetacean Welfare Study). Non-invasive bio-logging devices (Movement Tags) recorded the diving behavior and vertical habitat movements of 60 bottlenose dolphins at 31 zoos and aquariums that were accredited by the Alliance for Marine Mammal Parks and Aquariums and/or the Association of Zoos & Aquariums. Bottlenose dolphins wore a Movement Tag one day per week for two five-week data collection periods. Demographic variables, environmental enrichment programs, training programs, and habitat characteristics were associated with habitat usage. Longer dive durations and use of the bottom third of the habitat were associated with higher enrichment program index values. Dolphins receiving new enrichment on a monthly/weekly schedule also used the bottom third of the habitat more often than those receiving new enrichment on a yearly/year+ schedule. Dolphins that were managed in a group that was split into smaller subgroups during the day and were reunited into one group at night spent less time in the top third of the habitat than those who remained in a single group with consistent members at all times. Dolphins that were managed as subgroups with rotating members but were never united as one group spent less time in the bottom third of the habitat than those who remained in a single group with consistent members at all times. Taken together, the results suggested that management practices, such as enrichment and training programs, played a greater role in how dolphins interacted with their environment relative to the physical characteristics of the habitat.
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... The inclusion of additional biological samples shifted the focus from studies of population range and social patterns to broader scientific investigations of life history, population dynamics, body condition and health, social structure, communication, reproductive success, and effects of human interactions. Samples and measurements included indepth bloodwork analyses, genetic tests for population structure and paternity, ultrasonic measurement of blubber thickness, weight measurement, age determination (tooth growth layer group counts), further development of tags and tag attachments, and post-release population monitoring (14)(15)(16)(17)(18)(19). ...
Health Assessments of Common Bottlenose Dolphins (Tursiops truncatus): Past, Present, and Potential Conservation Applications
Article
Full-text available
  • Dec 2019
The common bottlenose dolphin (Tursiops truncatus) is a global marine mammal species for which some populations, due to their coastal accessibility, have been monitored diligently by scientists for decades. Health assessment examinations have developed a comprehensive knowledge base of dolphin biology, population structure, and environmental or anthropogenic stressors affecting their dynamics. Bottlenose dolphin health assessments initially started as stock assessments prior to acquisition. Over the last four decades, health assessments have evolved into essential conservation management tools of free-ranging dolphin populations. Baseline data enable comparison of stressors between geographic locations and associated changes in individual and population health status. In addition, long-term monitoring provides opportunities for insights into population shifts over time, with retrospective application of novel diagnostic tests on archived samples. Expanding scientific knowledge enables effective long-term conservation management strategies by facilitating informed decision making and improving social understanding of the anthropogenic effects. The ability to use bottlenose dolphins as a model for studying marine mammal health has been pivotal in our understanding of anthropogenic effects on multiple marine mammal species. Future studies aim to build on current knowledge to influence management decisions and species conservation. This paper reviews the historical approaches to dolphin health assessments, present day achievements, and development of future conservation goals.
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... Skin samples from 39 bottlenose dolphins collected from June 2004 through May 2009 by the Sarasota Dolphin Research Program (Sarasota, FL, United States), as part of capturerelease health assessments of the long-term resident Sarasota Bay dolphin community (Wells et al., 2004(Wells et al., , 2005 were used. This community has been studied since 1970, through at least six generations, and at any given time includes up to five concurrent generations within a single maternal lineage, and individuals up to 67 years of age (Irvine and Wells, 1972;Wells, 2014). As of 2015, the community was composed of 157.53 ± 43.05 SE dolphins (Tyson and Wells, 2016). ...
The Bottlenose Dolphin Epigenetic Aging Tool (BEAT): A Molecular Age Estimation Tool for Small Cetaceans
Article
Full-text available
  • Sep 2019
Age constitutes a critical parameter for the study of animal populations, providing information about development, environmental effects, survival, and reproduction. Unfortunately, age estimation is not only challenging in large, mobile and legally protected species, but often involves invasive sampling methods. The present work investigates the association between epigenetic modifications and chronological age in small cetaceans. For that purpose, DNA methylation at age-linked genes was characterized in an extensively studied, long-term resident common bottlenose dolphin (Tursiops truncatus) community from Sarasota Bay (FL, United States) for which sampled individuals have a known age. Results led to the identification of several CpG sites that are significantly correlated to chronological age in this species with the potential for sex to play a role in the modulation of this correlation. These findings have allowed for the development and validation of the “Bottlenose dolphin Epigenetic Age estimation Tool” (BEAT), improving minimally-invasive age estimation in free-ranging small cetaceans. Overall, the BEAT proved to be accurate in estimating age in these organisms. Given its minimally-invasive nature and potential large-scale implementation using skin biopsy samples, this tool can be used to generate age data from free-ranging small cetacean populations.
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... In the same region, NOAA has defined 10 BSE stocks, including the West Bay, Texas stock and neighbouring Galveston Bay stock (Waring et al., 2016). Throughout the Gulf of Mexico, long-term, year-round residency of bottlenose dolphins has been reported from nearly every BSE site where photoidentification (photo-ID) or tagging studies have been conducted, including those in Texas (Balmer et al., 2008;Hubard, Maze-Foley, Mullin, & Schroeder, 2004;Irvine & Wells, 1972;Maze & Würsig, 1999;Shane, 1980;Wells et al., 1987). The amount of movement between the BSE stocks and coastal stocks varies; however, in many cases residents primarily use BSE waters with limited movement into Gulf waters (Balmer et al., 2019;Fazioli, Hofmann, & Wells, 2006;Hayes et al., 2017;Wells et al., 2017). ...
Updated abundance estimates for common bottlenose dolphins ( Tursiops truncatus ) inhabiting West Bay, Texas
Article
  • Aug 2019
West Bay is located along the south‐west portion of Galveston Bay, Texas, and has been delimited as a bay, sound, and estuary (BSE) common bottlenose dolphin ( Tursiops truncatus ) stock area under the Marine Mammal Protection Act of 1972. The most recent abundance estimate available for the West Bay BSE stock is from 2001 and is considered outdated for management purposes. This study provides an updated abundance estimate using photo‐identification capture‐mark‐recapture (CMR) data collected from West Bay during the winter of 2014 and summer of 2015. The CMR data were analysed using both Pollock's robust design models and Poisson‐log normal mark‐resight models. Differences between the model types are discussed, and the abundance estimates derived from the mark‐resight models are recommended for management use (50.63 [unconditional SE 2.23] in the winter and 44.36 [unconditional SE 1.18] in the summer). Whereas the updated abundance estimates are higher than the previously reported estimates, which varied between 28 and 38, they still indicate that West Bay supports a small population of bottlenose dolphins. As a result, the West Bay BSE stock should be closely monitored for impacts, particularly those related to human caused stressors.
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... In the wild, bottlenose dolphins reside in shallow waters approximately 2 m deep when resources are abundant (e.g. Irvine and Wells, 1972;Wells et al., 1980). Shyan et al. (2002) concluded that larger pools in captive facilities may not be the preferred environments for dolphins; but since this is an isolated study a larger sample size is required to replicate findings, and may have been confounded by animals choosing to reside in shallower areas if they were near to kitchen or trainer areas. ...
Optimal marine mammal welfare under human care: Current efforts and future directions
Article
  • Sep 2017
  • BEHAV PROCESS
Marine mammals include cetaceans, pinnipeds, sirenians, sea otters and polar bears, many of which are charismatic and popular species commonly kept under human care in zoos and aquaria. However, in comparison with their fully terrestrial counterparts their welfare has been less intensively studied, and their partial or full reliance on the aquatic environment leads to unique welfare challenges. In this paper we attempt to collate and review the research undertaken thus far on marine mammal welfare, and identify the most important gaps in knowledge. We use 'best practice case studies' to highlight examples of research promoting optimal welfare, include suggestions for future directions of research efforts, and make recommendations to strive for optimal welfare, where it is currently lacking, above and beyond minimum legislation and guidelines. Our review of the current literature shows that recently there have been positive forward strides in marine mammal welfare assessment, but fundamental research is still required to validate positive and negative indicators of welfare in marine mammals. Across all marine mammals, more research is required on the dimensions and complexity of pools and land areas necessary for optimal welfare, and the impact of staff absence for most of the 24-hour day, as standard working hours are usually between 0900-1700.
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... Nevertheless, as has been noted by many researchers, there is behavioral and genetic interaction between the resident communities and members of the next category (see below) of the three NMFS-designated coastal stocks in U.S. Gulf waters to about the 20 m (66 ft) depth.Urian et al. 1996). Studies by Randall S. Wells and colleagues describe the long-term structure and stability of bottlenose dolphin residents of greater Sarasota Bay, Florida, since 1970 (Irvine and Wells 1972;Scott et al. 1990;Wells 1991Wells , 2003). By photo-identification and periodic captures for age, reproductive, and health data, presently five generations have been tracked in the area, including several first seen in the 1970s that are still living. ...
Marine Mammals of the Gulf of Mexico
Chapter
  • Jun 2017
Recorded knowledge of marine mammals of the Gulf began with commercial whaling of sperm whales, short-finned pilot whales, and Risso’s dolphins in the 1700s and 1800s, progressed to natural history observations and one of the first volunteer stranding organizations, the Texas Marine Mammal Stranding Network, in the 1970s. The vegetarian sirenian, the West Indian manatee (Trichechus manatus), occurs mainly in Florida. All others are cetaceans, members of the whale and dolphin clades. There are no porpoises, sea lions, fur seals, or true seals in the Gulf. The most common cetacean in the Gulf numerically is the pantropical spotted dolphin (Stenella attenuata), and the one with most biomass is the sperm whale (Physeter macrocephalus), common in mid-depth waters off Louisiana and the shelf break off Texas. Major anthropogenic threats exist for all marine mammals but do not appear to be as intensive in the Gulf as in several other oceanic basins. Threats to marine mammals in the Gulf include prey depletion, incidental mortality, injury due to fisheries, intentional and direct takes, vessel strikes, disturbance, acoustic (noise) pollution, chemical contamination, ingestion of solid debris, oil spills, and aspects of ecosystem change.
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