Gabriela Tezanos-Pinto

Massey University · Institute of Natural and Mathematical Sciences

Regional populations of bottlenose dolphins (Tursiops truncatus) around New Zea- land are genetically isolated from each other and the species was recently classified as nationally endangered based on relatively small population sizes and reports of high calf mortality. Here, we estimate the abundance and trends in one of these regional populations...

Bottlenose dolphins (Tursiops truncatus) in the Bay of Islands, New Zealand, have been studied for almost two decades. Since 2003, fewer than 150 dolphins visited the bay during each season and the local unit has declined 7.5% annually from 1997 to 2006. The causes of decline are unclear but probably include mortality and emigration. Here, we used...

LAJAM Special Volume on Tursiops in the Southwest Atlantic Ocean is introduced.

When an individual's reproductive success relies on winning fights to secure mating opportunities, bearing larger weapons is advantageous. However, sexual selection can be extremely complex, and over an animal's life the opportunity to mate is influenced by numerous factors. We studied a wild population of giraffe weevils (Lasiorhynchus barbicornis...

Climatic changes have caused major environmental restructuring throughout the world's oceans. Marine organisms have responded to novel conditions through various biological systems, including genomic adaptation. Growing accessibility of next-generation DNA sequencing methods to study nonmodel species has recently allowed genomic changes underlying...

An understanding of population structure and connectivity at multiple spatial scales is required to assist wildlife conservation and management. This is particularly critical for widely distributed and highly mobile marine mammals subject to fisheries by-catch. Here, we present a population genomic assessment of a near-top predator, the common dolp...

This is an infographic showing the main results of Peters et al. 2020 in MEPS

Dolphins are among the largest and most diverse predators in marine ecosystems, but our understanding of their foraging ecology, which is crucial for ecosystem management, is poor. Delphinus delphis (common dolphins) are found in tropical and temperate waters globally. Stomach content studies indicate they are opportunistic predators that feed loca...

Two ecotypes of the common bottlenose dolphin (Tursiops truncatus) occur in New Zealand waters: a widely studied Nationally Endangered coastal ecotype and a little‐known oceanic ecotype. Site fidelity and association patterns of the oceanic ecotype, and home range overlap with the coastal ecotype, are examined from photo‐identification records coll...

Environmental variations result in different selection pressures acting upon a species, promoting niche specialization with adaptation to a specific habitat resulting in evolution. Consequently, genetically divergent subpopulations or ecotypes are formed. Ecotype characterization involves morphologic, ecological and even genetic differentiation. Ho...

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Population parameters of poorly marked gregarious species are difficult to estimate. This is the case for common dolphins (Delphinus sp.), a genus known for its lack of distinctive marks resulting in a low mark ratio. Furthermore, the widespread nature of common dolphins results in low recaptures. We developed reliable photo-identification protocol...

Survey tracks (black lines) of tour and research vessels for each year (a) and season (b) in the inner Hauraki Gulf, New Zealand. (DOCX)

Definitions of age-classes recorded for common dolphins (Delphinus sp.) in the Hauraki Gulf, New Zealand [1]. (DOCX)

Photographic quality (PQ) categories used to examine adult common dolphin images in the Hauraki Gulf, New Zealand. Images were classified as: a) poor; b) fair; c) good, or; d) excellent quality. (DOCX)

Sample sizes (n, the number of high-quality photographs for highly distinctive (D1), distinctive (D2) and non-distinctive (D3) individuals) and proportions of marked individuals (θ^) used to estimate either the seasonal or super-population abundance of common dolphins using the Hauraki Gulf between 2010 and 2013. Here nTotal represents the sum of n...

Results of goodness of fit (GOF) tests conducted in U-CARE 2.02 in a Cormack-Jolly-Seber framework for adult common dolphins (Delphinus sp.) photo-identified between January 2010 and December 2013 in the Hauraki Gulf, New Zealand. Results are also included from the global test (GT; test 2+3). GOF tests were conducted for highly distinctive individu...

Nick/notch depth categories used to examine adult common dolphin (Delphinus sp.) images in the Hauraki Gulf, New Zealand. Individuals were classified as having either minor or major nicks/notches [4]. (DOCX)

Cumulative discovery curve (black line) indicating the number of newly identified adult common dolphins (Delphinus sp.) between January 2010 and December 2013 in the Hauraki Gulf, New Zealand, including a 1:1 slope (grey line) as if all individuals documented were new additions to the catalogue. (DOCX)

Description of attribute criteria used to examine the photographic quality (PQ) of common dolphin images in the Hauraki Gulf, New Zealand. Images were assessed according to focus, exposure, orientation, and visible percentage (adapted from [2–3]). When assessing quality criteria each attribute was considered independently to avoid bias/contradictio...

The current conservation status of the bottlenose dolphin (Tursiops truncatus) under the IUCN is ‘least concern’. However, in the Caribbean, small and localized populations of the ‘inshore form’ may be at higher risk of extinction than the ‘worldwide distributed form’ due to a combination of factors including small population size, high site fideli...

Graphic representation of Evanno et al. [71] ad hoc statistic ∆K, which shows a clear peak in K = 2. (DOCX)

Mean and Stdev LnPK, and DeltaK results for all K (1 to 10), according to STRUCTURE analyses. (DOCX)

Microsatellite data. (XLSX)

Two forms of the common bottlenose dolphin (Tursiops truncatus) are known to occur in New Zealand waters: a widely studied nationally endangered coastal form and a little known oceanic form. Despite reported morphological differences, the two forms are considered to be taxonomically identical. Oceanic bottlenose dolphin minimum home-ranges, site fi...

ABSTRACT: Bryde’s whales Balaenoptera edeni in New Zealand are classified as ‘nationally critical’ according to the New Zealand Threat Classification System. In the Hauraki Gulf, Bryde’s whales occur year round and are subject to ship-strike mortality events. Photo-identification surveys were conducted to estimate local abundance, apparent survival...

Bryde’s whales (Balaenoptera edeni/brydei) in New Zealand are classified as ‘nationally critical’. In the Hauraki Gulf, Bryde’s whales occur year-round and are subject to some mortality, as evidenced by ship strikes and entanglements. Opportunistic and directed photo-identification surveys were conducted to evaluate site fidelity, seasonal abundanc...

The taxonomic status of many dolphin populations remains uncertain in poorly studied regions of the world's ocean. Here we attempt to clarify the phylogenetic identity of two distinct forms of bottlenose dolphins (Tursiops spp.) described in the Melanesian region of the Pacific Ocean. Mitochondrial DNA control region sequences from samples collecte...

The taxonomic status of many dolphin populations remains uncertain in poorly studied regions of the world's ocean. Here we attempt to clarify the phylogenetic identity of two distinct forms of bottlenose dolphins (Tursiops spp.) described in the Melanesian region of the Pacific Ocean. Mitochondrial DNA control region sequences from samples collecte...

Conservation initiatives are typically constrained by economic circumstances, a factor certainly true for marine mammal conservation in New Zealand. Most research in this field has been conducted following concerns over anthropogenic impacts on populations and has therefore been funded and/or driven by stakeholder interest. Bottlenose dolphins Turs...

There are three genetically isolated coastal populations of bottlenose dolphins (Tursiops truncatus) in New Zealand. The species is classified as ‘nationally endangered’ based on reports of high calf mortality and local declines in abundance in the Bay of Islands and Doubtful Sound. Long-term studies conducted in the Bay of Islands over 13 years re...

In New Zealand, most marine mammal scientific research has historically been driven by stakeholder interest. For example, the vast majority of research contracts have been generated from either the Ministry for Primary Industries or the Department of Conservation as a consequence of concerns over levels of incidental bycatch or tourism impacts. Gre...

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We analyse short-term individual and group behavioural reactions and long-term individual responses of bottlenose dolphins (Tursiops truncatus) in New Zealand to remote skin biopsy sampling. The biopsy system employed uses a small stainless steel tip (5-mm diameter, 9-mm length) mounted on a lightweight polycarbonate projectile, fired from a modifi...

A small, resident population of bottlenose dolphins in Fiordland, New Zealand, was recently classified as ‘critically endangered’ by the IUCN. This population is estimated to number less than 205 and thought to be isolated from the other two coastal populations in New Zealand. Here, we investigated differentiation among the three bottlenose dolphin...

This study presents the first comprehensive genetic analyses of common bottlenose dolphin (Tursiops truncatus) based on mitochondrial DNA and microsatellite loci in the Wider Caribbean. Live captures of bottlenose dolphins have been occurring since the turn of the 20th century in Wider Caribbean waters where little is known about their population s...

Bottlenose dolphins (Tursiops truncatus) are distributed into three genetically differentiated populations in New Zealand: the north-eastern coast of the North Island, the Marlborough Sounds and Fiordland in the South Island. Along the north-eastern coast of the North Island, the Bay of Islands presents a unique opportunity to study this population...

Bottlenose dolphins (Tursiops truncatus) occupy a wide range of coastal and pelagic habitats throughout tropical and temperate waters worldwide. Around New Zealand, bottlenose dolphins inhabit three discontinuous regions in the north-eastern coast of the North Island, Marlborough Sound and Fiordland in the South Island. All these populations are su...

A Worldwide Perspective on the Population Structure and Genetic Diversity of Bottlenose Dolphins (Tursiops truncatus) in New Zealand. J Hered (2009) 100 (1): 11-24. https://doi.org/10.1093/jhered/esn039

Bottlenose dolphins (Tursiops truncatus) are a cosmopolitan species distributed in a wide range of coastal, insular and pelagic habitats. They have high plasticity adapting to different environmental conditions; in some regions, coastal or “inshore” forms differ genetically and morphologically from pelagic or “offshore” forms despite any obvious bo...

8) Caribbean Stranding Network, San Juan, Puerto Rico. Bottlenose dolphins (Tursiops truncatus) inhabit a wide range of coastal, insular and pelagic habitats throughout tropical and temperate waters around the world. In some regions, coastal forms differ genetically and morphologically from pelagic forms despite no obvious boundaries to interchange...