Effects of Human Activities on Coastal Dolphin Behavior

This dissertation contributes to our understanding of anthropogenic effects on wildlife, a central question in the growing field of conservation behavior. I present three case studies of coastal delphinid species in diverse ecosystems with varied human pressures. I examine how 1) common bottlenose dolphins (Tursiops truncatus) in a narrow congested waterway respond to heavy vessel traffic, 2) Indo-Pacific humpback dolphins (Sousa chinensis) respond to chronic maritime construction and associated vessel activity, and 3) dusky dolphins (Lagenorhynchus obscurus) use distinct patches within a bay that supports shellfish aquaculture. In each study, group focal follows were conducted using non-invasive shore-based theodolite tracking. Data collection included behavioral states, movement patterns and habitat-use patterns. Metrics to evaluate alterations in movement patterns included swimming speed, reorientation rate, and linearity. Data to evaluate alterations in habitat-use included behavioral activity states and track duration among habitat patches. Multivariate generalized additive models identified significant explanatory variables. Dolphin movement and habitat-use patterns were good indicators of response to human activity across diverse species and ecosystems. Bottlenose dolphins avoided tour boats and were attracted to commercial trawlers that may facilitate prey accessibility. Current voluntary dolphin-viewing recommendations do not protect dolphins from behavioral harassment, but dolphins did not abandon the area, which may reflect a lack of ecologically similar habitat nearby. Humpback dolphins avoided areas near chronic construction activity during the day, but some returned at night when human activity decreased. Dusky dolphins used defined patches within the bay in different ways. Mid-bay and nearshore patches reflect areas that may yield greater benefits relative to prey ball herding opportunities, whereas patches near mussel farms reflect areas that may yield greater benefits relative to non-prey ball foraging opportunities. Flexibility in foraging tactics occurred across study sites and species, and allows dolphins to adjust to fluctuating environments with ephemeral and patchily distributed prey. Behaviors are likely influenced by human activity, prey characteristics, and accessibility to alternate habitats that support prey. Integration of data on prey characteristics (e.g., fish species, abundance, and distribution) in future research will enhance our understanding of factors influencing dolphin behavior in these dynamic systems

Effects of Human Activities on Coastal Dolphin Behavior

This dissertation contributes to our understanding of anthropogenic effects on wildlife, a central question in the growing field of conservation behavior. I present three case studies of coastal delphinid species in diverse ecosystems with varied human pressures. I examine how 1) common bottlenose dolphins (Tursiops truncatus) in a narrow congested waterway respond to heavy vessel traffic, 2) Indo-Pacific humpback dolphins (Sousa chinensis) respond to chronic maritime construction and associated vessel activity, and 3) dusky dolphins (Lagenorhynchus obscurus) use distinct patches within a bay that supports shellfish aquaculture. In each study, group focal follows were conducted using non-invasive shore-based theodolite tracking. Data collection included behavioral states, movement patterns and habitat-use patterns. Metrics to evaluate alterations in movement patterns included swimming speed, reorientation rate, and linearity. Data to evaluate alterations in habitat-use included behavioral activity states and track duration among habitat patches. Multivariate generalized additive models identified significant explanatory variables. Dolphin movement and habitat-use patterns were good indicators of response to human activity across diverse species and ecosystems. Bottlenose dolphins avoided tour boats and were attracted to commercial trawlers that may facilitate prey accessibility. Current voluntary dolphin-viewing recommendations do not protect dolphins from behavioral harassment, but dolphins did not abandon the area, which may reflect a lack of ecologically similar habitat nearby. Humpback dolphins avoided areas near chronic construction activity during the day, but some returned at night when human activity decreased. Dusky dolphins used defined patches within the bay in different ways. Mid-bay and nearshore patches reflect areas that may yield greater benefits relative to prey ball herding opportunities, whereas patches near mussel farms reflect areas that may yield greater benefits relative to non-prey ball foraging opportunities. Flexibility in foraging tactics occurred across study sites and species, and allows dolphins to adjust to fluctuating environments with ephemeral and patchily distributed prey. Behaviors are likely influenced by human activity, prey characteristics, and accessibility to alternate habitats that support prey. Integration of data on prey characteristics (e.g., fish species, abundance, and distribution) in future research will enhance our understanding of factors influencing dolphin behavior in these dynamic systems

Non-binary Living in a Binary World: The Unlabeled Experience

Both popular media and social science research suggest that gender/sexual identities and roles that have dominated western society are being challenged (Budgeon, 2014). Heteronormative assumptions and the gender binary are rapidly evolving to capture experiences that reflect greater diversity (Diamond, 2005; Nagoshi et al., 2012), including those that extend beyond labels. We surveyed 915 individuals regarding their gender identity, sexual orientation, and numerous psychological measures related to well-being, in order to understand the experience of those who choose to remain unlabeled. The data would suggest that those not ascribing to the gender binary have lower reported satisfaction with life across several axes when compared to cisgender participants. Explaining their ‘unlabeled’ status, participants described their primary identification as human, expressed discomfort with gender-based assumptions and rejected constrictions of the gender binary

Effects of Human Activities on Coastal Dolphin Behavior

This dissertation contributes to our understanding of anthropogenic effects on wildlife, a central question in the growing field of conservation behavior. I present three case studies of coastal delphinid species in diverse ecosystems with varied human pressures. I examine how 1) common bottlenose dolphins (Tursiops truncatus) in a narrow congested waterway respond to heavy vessel traffic, 2) Indo-Pacific humpback dolphins (Sousa chinensis) respond to chronic maritime construction and associated vessel activity, and 3) dusky dolphins (Lagenorhynchus obscurus) use distinct patches within a bay that supports shellfish aquaculture. In each study, group focal follows were conducted using non-invasive shore-based theodolite tracking. Data collection included behavioral states, movement patterns and habitat-use patterns. Metrics to evaluate alterations in movement patterns included swimming speed, reorientation rate, and linearity. Data to evaluate alterations in habitat-use included behavioral activity states and track duration among habitat patches. Multivariate generalized additive models identified significant explanatory variables. Dolphin movement and habitat-use patterns were good indicators of response to human activity across diverse species and ecosystems. Bottlenose dolphins avoided tour boats and were attracted to commercial trawlers that may facilitate prey accessibility. Current voluntary dolphin-viewing recommendations do not protect dolphins from behavioral harassment, but dolphins did not abandon the area, which may reflect a lack of ecologically similar habitat nearby. Humpback dolphins avoided areas near chronic construction activity during the day, but some returned at night when human activity decreased. Dusky dolphins used defined patches within the bay in different ways. Mid-bay and nearshore patches reflect areas that may yield greater benefits relative to prey ball herding opportunities, whereas patches near mussel farms reflect areas that may yield greater benefits relative to non-prey ball foraging opportunities. Flexibility in foraging tactics occurred across study sites and species, and allows dolphins to adjust to fluctuating environments with ephemeral and patchily distributed prey. Behaviors are likely influenced by human activity, prey characteristics, and accessibility to alternate habitats that support prey. Integration of data on prey characteristics (e.g., fish species, abundance, and distribution) in future research will enhance our understanding of factors influencing dolphin behavior in these dynamic systems

Effects of Human Activities on Coastal Dolphin Behavior

This dissertation contributes to our understanding of anthropogenic effects on wildlife, a central question in the growing field of conservation behavior. I present three case studies of coastal delphinid species in diverse ecosystems with varied human pressures. I examine how 1) common bottlenose dolphins (Tursiops truncatus) in a narrow congested waterway respond to heavy vessel traffic, 2) Indo-Pacific humpback dolphins (Sousa chinensis) respond to chronic maritime construction and associated vessel activity, and 3) dusky dolphins (Lagenorhynchus obscurus) use distinct patches within a bay that supports shellfish aquaculture. In each study, group focal follows were conducted using non-invasive shore-based theodolite tracking. Data collection included behavioral states, movement patterns and habitat-use patterns. Metrics to evaluate alterations in movement patterns included swimming speed, reorientation rate, and linearity. Data to evaluate alterations in habitat-use included behavioral activity states and track duration among habitat patches. Multivariate generalized additive models identified significant explanatory variables. Dolphin movement and habitat-use patterns were good indicators of response to human activity across diverse species and ecosystems. Bottlenose dolphins avoided tour boats and were attracted to commercial trawlers that may facilitate prey accessibility. Current voluntary dolphin-viewing recommendations do not protect dolphins from behavioral harassment, but dolphins did not abandon the area, which may reflect a lack of ecologically similar habitat nearby. Humpback dolphins avoided areas near chronic construction activity during the day, but some returned at night when human activity decreased. Dusky dolphins used defined patches within the bay in different ways. Mid-bay and nearshore patches reflect areas that may yield greater benefits relative to prey ball herding opportunities, whereas patches near mussel farms reflect areas that may yield greater benefits relative to non-prey ball foraging opportunities. Flexibility in foraging tactics occurred across study sites and species, and allows dolphins to adjust to fluctuating environments with ephemeral and patchily distributed prey. Behaviors are likely influenced by human activity, prey characteristics, and accessibility to alternate habitats that support prey. Integration of data on prey characteristics (e.g., fish species, abundance, and distribution) in future research will enhance our understanding of factors influencing dolphin behavior in these dynamic systems

Abundance and Occurrence of Common Bottlenose Dolphins (Tursiops truncatus) in Three Estuaries of the Northwestern Gulf of Mexico

Current abundance estimates for populations of common bottlenose dolphins (Tursiops truncatus, Montagu, 1821) in bays, sounds, and estuaries are lacking throughout most of the northwestern Gulf of Mexico, including areas of Texas and western Louisiana. To address this issue, we conducted 92 small-boat photographic identification surveys covering ~2000 km2 and comprising ~11,000 km of track-line in winter and summer seasons in West Bay, TX (2014 – 2015, n = 25), the Galveston Bay, TX system (2016, n = 50), Sabine Lake, TX (2017, n = 17), and adjacent coastal waters. Individual dolphin encounter histories were constrained by spatiotemporal parameters to approximately represent 1) a “Bay” estimate of individuals limited to the interior of each embayment, and 2) a “Selective” estimate of the number of individuals in each survey area (including nearshore coastal waters), filtered for potential transient dolphins. Using the Selective dataset, estimated dolphins (95% CI) were (winter and summer, respectively) 38 (29 – 47) and 37 (33 – 40) for West Bay, 842 (694 – 990) and 1132 (846 – 1417) for Galveston Bay, and 122 (73 – 170) and 162 (114 – 210) for Sabine Lake. A range of 4-15% of marked individuals in each study area were identified as inter-bay matches. These results provide new insights on the potential spatial range of each population, update previous abundance estimates for West Bay and Galveston Bay, and contribute novel population information for Sabine Lake and adjacent coastal waters of the northwestern Gulf of Mexico

Humpback Whale Movements and Behavior in Response to Whale-Watching Vessels in Juneau, AK

The whale-watching industry in Juneau, Alaska relies primarily on the presence of North Pacific humpback whales (Megaptera novaeangliae). To meet demands from the rapidly growing tourism industry, the number of whale-watching vessels in this region has tripled over the last 18 years. As a result, increased vessel presence could have negative effects on humpback whales, ranging from short-term behavioral disturbance to long-term impacts.The whale-watching industry in Juneau, Alaska relies primarily on the presence of North Pacific humpback whales (Megaptera novaeangliae). To meet demands from the rapidly growing tourism industry, the number of whale-watching vessels in this region has tripled over the last 18 years. As a result, increased vessel presence could have negative effects on humpback whales, ranging from short-term behavioral disturbance to long-term impacts. The current humpback whale viewing regulations are outdated and may not be as effective as they were 18 years ago, when both the whale-watching industry and humpback whale population were smaller. The present study assessed how humpback whale movement and behavioral patterns were affected by (1) vessel presence and number of vessels present, and (2) time spent in the presence of vessels. The study also determined how humpback whale behavioral state transitions were affected by vessel presence. A total of 201 humpback whale focal follows were conducted during summer 2016 and 2017. Based on linear mixed effects models, whales in the presence (vs. absence) of vessels exhibited 38.9% higher deviation in linear movement (p = 0.001), 6.2% increase in swimming speed (p = 0.047) and a 6.7% decrease in inter-breath intervals (IBI) (p = 0.025). For each additional vessel present, deviation increased by 6.2% (p = 0.022) and IBI decreased by 3.4% (p = 0.001). As time spent in the presence of vessels increased, respiration rate increased (p = 0.011). Feeding and traveling humpback whales were likely to maintain their behavioral state regardless of vessel presence, while surface active humpback whales were likely to transition to traveling in the presence of vessels. These short-term changes in movement and behavior in response to whale-watching vessels could lead to cumulative, long-term consequences, negatively impacting the health and predictability of the resource on which the industry relies. Current formal vessel approach regulations and voluntary guidelines should be revisited to reduce vessel pressure and mitigate potential negative effects of this growing whale-watching industry.This project would not have been possible without data collection assistance by Chase Ammon, Madison Bargas, Taelor Brandon, Cody Crumpton, Dana Flerchinger, Holly Kelchner, Anneliese Moll, Breanna O’Farrell, Lindsey Overcast, Robert Schuler, and Margaret Sherman. Logistical support at the National Oceanic and Atmospheric Administration Ted Steven’s Marine Research Institute was provided by John Moran and Gordon Garcia, and access to the Point Retreat Lighthouse field site was generously provided by Dave Benton and Lori Tefler of the Alaska Lighthouse Association.Ye

Student Showcase – Defending Democracy: Government Responsibility vs. Individual Rights

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