Carlos Olavarria

Centro de Estudios Avanzados en Zonas Áridas | CEAZA

Off Northern Chile, baleen whales use the area around Isla Chañaral as a feeding ground where they forage on euphausiids. Isla Chañaral is part of the highly productive Humboldt Archipelago (∼ 28°S-29°S) within the Humboldt Current System (HCS). In this study, we seek to understand the sub-mesoscale spatial distribution of fin and blue whales and t...

Context Until recently, very little was known about the species diversity and occurrence of cetaceans in the Republic of Palau. A dedicated scientific investigation into the occurrence and distribution of island associated cetaceans in Palau was conducted in 2012 and 2013. Aims The aim of this project was to investigate the diversity and distributi...

The 20 th century commercial whaling industry severely reduced populations of great whales throughout the Southern Hemisphere. The effect of this exploitation on genetic diversity and population structure remains largely undescribed. Here, we compare pre- and post-whaling diversity of mitochondrial DNA (mtDNA) control region sequences for three gre...

Cetacean strandings are regularly recorded along the coast of Chile. However, crucial information such as species and sex of the individuals involved in these events can often be difficult to assess. In this context, the use of molecular tools as a complementary method can improve a stranding database, particularly by correcting misidentifications...

The deep sea is the largest ecosystem on Earth, yet little is known about the processes driving patterns of genetic diversity in its inhabitants. Here, we investigated the macro- and microevolutionary processes shaping genomic population structure and diversity in two poorly understood, globally distributed, deep-sea predators: Cuvier’s beaked whal...

Humpback whales (Megaptera novaeangliae) seasonally migrate between their corresponding breeding and feeding grounds; however, some individual whales deviate from this pattern migrating to different breeding or feeding grounds. Here, we report the first recorded movement of a humpback whale between the Antarctic Peninsula and the east coast of Aust...

Commerson’s dolphins (Cephalorhynchus commersonii) are separated into the subspecies C. c. commersonii, found along southern South America (SA) and the Falkland Islands/Islas Malvinas (FI/IM), and C. c. kerguelenensis, restricted to the subantarctic Kerguelen Islands (KI). Following the dispersal model proposed for the genus, the latter is thought...

The study of cetacean strandings was globally recognised as a priority topic at the 2019 World Marine Mammal Conference, in recognition of its importance for understanding the threats to cetacean communities and, more broadly, the threats to ecosystem and human health. Rising multifaceted anthropogenic and environmental threats across the globe, as...

• The sei whale (Balaenoptera borealis) presents a disjointed geographic distribution. Significant genetic divergence between sei whales from the North Atlantic (NA) and North Pacific (NP) have been recorded; however, limited samples from the Southern Hemisphere (SH) have precluded a global analysis. • The largest recorded mass mortality event occu...

Four fin whale sub-species are currently considered valid: Balaenoptera physalus physalus in the North Atlantic, B. p. velifera in the North Pacific, B. p. quoyi and B. p. patachonica in the Southern Hemisphere. The last, not genetically validated, was described as a pygmy-type sub-species, found in low to mid latitudes of the Southern Hemisphere....

We analyzed 114 DNA samples collected in different locations within the stock G breeding grounds, including Ecuador and the northern and southern Pacific of Colombia. We genotyped 15 microsatellite loci, sexed all samples, and performed genotype comparisons. Genotype comparisons were done using a DNA register of previously genotyped individuals fro...

The matrilineal long-finned pilot whale presents an antitropical distribution and is divided into two subspecies, one in the temperate seas of the Southern Hemisphere and the other restricted to the North Atlantic and Mediterranean. Until now, population genetic and phylogeographic studies have included localities of most of its Northern Hemisphere...

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We test the ability of Very High Resolution satellite (VHR) imagery to detect stranded whales using both manual and automated methods. We use the 2015 mass mortality event in the Gulf of Penas locality, central Patagonia, Chile, as an initial case study. This event was the largest known mass mortality of baleen whales, with at least 343 whales, mai...

• Fin whales (Balaenoptera physalus) have been documented along the coast of Chile since the early 20th century; however, information on their ecology and movement patterns remains poorly known. • In the spring of 2015, six implantable satellite tags were deployed on fin whales around the marine reserves of Isla Chañaral and Islas Choros‐Damas (app...

Humpback whales (Megaptera novaeangliae) congregate to breed during the austral winter near tropical islands of the South Pacific (Oceania). It has long been assumed that humpback whales from Oceania migrate primarily to Antarctic feeding grounds directly south (International Whaling Commission Management Areas V and VI); however, there are few rec...

Southern Hemisphere humpback whales breed in tropical waters and migrate to Antarctica to forage. While the breeding grounds are well defined, the population structure on Antarctic feeding grounds is poorly described. The Western Antarctic Peninsula (WAP) is of particular interest, where rapidly changing environmental conditions could alter prey di...

Between the 1940s and 1970s Southern Hemisphere populations of humpback whales (including eastern Australia and Oceania populations) were hunted to near extinction by extensive commercial whaling activities in Antarctica, with fewer whales taken in shore whaling operations in New Zealand, Australia (including Norfolk Island) and Tonga. Variable rat...

The description of genetic population structure over a species’ geographic range can provide insights into its evolutionary history and also support effective management efforts. Assessments for globally distributed species are rare, however, requiring significant international coordination and collaboration. The global distribution of demographica...

The South American sea lion (Otaria flavescens) is widely distributed along the southern Atlantic and Pacific coasts of South America with a history of significant commercial exploitation. We aimed to evaluate the population genetic structure and the evolutionary history of South American sea lion along its distribution by analyses of mitochondrial...

List of individuals that bear each mitochondrial DNA control region haplotype, and the respective GenBank number. Absolute frequency in the sample and geographic distribution of haplotypes for South American sea lion. (DOCX)

List of individuals that bear each mitochondrial DNA cytochrome b haplotype. Absolute frequency in the sample and geographic distribution of haplotypes for South American sea lion. (DOCX)

Extended Bayesian skyline plot showing the effective population size fluctuation of South American sea lions populations throughout time based on the mtDNA control region. Internal dashed lines are median estimates and thin lines and coloured areas are the 95% Central Posterior Density (CPD) intervals. Nef, effective female population size (log sca...

Extended Bayesian skyline plot showing the effective population size fluctuation of South American sea lions populations throughout time based on the mtDNA control region. Internal black dashed lines are median estimates and thin lines are the 95% CPD intervals. Thin green lines are the individual population trajectories. Nef, effective female popu...

Species and access number of sequences downloaded from GenBank used to estimate the Bayesian phylogeny (Fig 3). (DOCX)

Genetic diversity of South American sea lions for each locus per clustered localities and for the species as whole. (A) Number of alleles, (E) = exclusive alleles, (Ho) observed heterozygosity, (He) expected heterozygosity.* Loci that deviated from HW equilibrium after Bonferroni correction. (DOCX)

Plots from STRUCTURE HARVESTER performed with Evanno’s method. (A) Highest value of (ΔK) = 79.20 on K = 2. (B) Mean of estimated Ln probability of data (± sd) averaging ten runs from K = 1 to K = 10. (TIF)

STRUCTURE bar plot from the test for migrants or hybrids between oceans using the sampling locations (in this case the ocean basin) and the USEPOPINFO model. Each bar is one individual and each colour represents the assignment probability of the individual to belong to that genetic cluster. (TIF)

Latitudinal preferences within the breeding range have been suggested for Breeding Stock G humpback whales that summer in different feeding areas of the eastern South Pacific. To address this hypothesis, humpback whales photo-identified from the Antarctic Peninsula and the Fueguian Archipelago (southern Chile) were compared with whales photo-identifie...

While large mass mortality events (MMEs) are well known for toothed whales, they have been rare in baleen whales due to their less gregarious behaviour. Although in most cases the cause of mortality has not been conclusively identified, some baleen whale mortality events have been linked to bio-oceanographic conditions, such as harmful algal blooms...

National Fisheries Service cruise report.

While large mass mortality events (MMEs) are well known for toothed whales, they have been rare in baleen whales due to their less gregarious behaviour. Although in most cases the cause of mortality has not been conclusively identified, some baleen whale mortality events have been linked to bio-oceanographic conditions, such as harmful algal blooms...

Humpback whales wintering in tropical waters along the Atlantic and Pacific coasts of the South American continent are thought to represent distinct populations or “stocks.” Here we present the first analysis of genetic differentiation and estimates of gene flow between these breeding stocks, based on both mitochondrial DNA (mtDNA) control region s...

While large mass mortality events (MMEs) are well known for toothed whales, they have been rare in baleen whales due to their less gregarious behaviour. Although in most cases the cause of mortality has not been conclusively identified, some baleen whale mortality events have been linked to bio-oceanographic conditions, such as harmful algal blooms...

While large mass mortality events (MMEs) are well known for toothed whales, they have been rare in baleen whales due to their less gregarious behaviour. Although in most cases the cause of mortality has not been conclusively identified, some baleen whale mortality events have been linked to bio-oceanographic conditions, such as harmful algal blooms...

Since the decimation of the southern right whale Eubalaena australis population in New Zealand by whaling, research on its recovery has focused on the wintering ground at the Auckland Islands, neglecting potentially important wintering habitat at Campbell Island. For the first time in 20 years we conducted an expedition to sub-Antarctic Campbell Is...

The complementarity of historical and contemporary processes contributes to understanding the genetic structure of continuously distributed marine species with high dispersal capabilities. Cephalorhynchus eutropia, has a continuous coastal distribution with strong genetic differentiation identified by nuclear DNA markers. We explored the historical...

Eight blue whales were photo-identified from coastal waters around New Zealand in 2015: seven from the South Island and one from Raoul Island (of the Kermadec Islands). Our collection of New Zealand blue whale photo-identifications now totals 38 individuals (27 left sides, 25 right sides). The 2015 photos were compared to one another and to 31 iden...

Here we review the published records of mtDNA control region sequences of southern hemisphere humpback whales as a first step in developing a validated register of haplotypes for future analyses of interest to the Scientific Committee of the International Whaling Commission. We restricted our initial review to sequences submitted to GenBank as 'pop...

Humpback whales (Megaptera novaeangliae) undertake seasonal migrations between low-latitude breeding grounds in winter and high-latitude feeding grounds in summer. In the Southern Hemisphere, seven primary breeding stocks have been identified based on tropical distribution between which there is limited gene flow. In the summer, these stocks are di...

Hector's dolphins (Cephalorhynchus hectori hectori) are distributed discontinuously around the South Island of New Zealand, with genetically differentiated regional populations along the east, west and south coasts. Fine-scale assessments of local population structure are needed to better understand the role of corridors and local dispersal on the...

Blue whales are infrequently reported from New Zealand and their taxonomic status is unclear. Here we present new information on the residency, external morphology, and habitat use of blue whales encountered in New Zealand waters. Thirty-one blue whales were photo-identified around the North and South Islands of New Zealand from 2004-2014 in seven...

The Eastern South Pacific humpback whale population winter primarily off Colombia and Ecuador, and migrate south to the Antarctic Area I feeding ground during the austral summer. In recent years humpback whales have been recorded feeding in the Patagonian channels of South America during the summer and fall seasons. Previously, a first migratory li...

While the breeding grounds of Southern Hemisphere humpback whales are generally well defined, the population structure on Antarctic feeding grounds is largely uncertain. This is of particular interest around the Antarctic Peninsula (AP) where rapidly changing environmental conditions may alter prey distribution or migration pathways. To examine cha...

Understanding genetic differentiation and speciation processes in marine species with high dispersal capabilities is challenging. The Chilean dolphin, Cephalorhynchus eutropia, is the only endemic cetacean of Chile and is found in two different coastal habitats: a northern habitat with exposed coastlines, bays and estuaries from Valparaíso (33°02'S...

Since its near extirpation during the period of industrial whaling in the early and mid 20th century, the once common Antarctic blue whale Balaenoptera musculus intermedia remains extremely rare. While annual systematic surveys around Antarctica from 1978 to 2009 recorded only 216 visual encounters of this species, their loud and distinctive calls...

Humpback whales (Megaptera novaeangliae) annually undertake the longest migrations between seasonal feeding and breeding grounds of any mammal. Despite this dispersal potential, discontinuous seasonal distributions and migratory patterns suggest that humpbacks form discrete regional populations within each ocean. To better understand the worldwide...

Previous underwater recordings made in New Zealand have identified a complex sequence of low frequency sounds that have been attributed to blue whales based on similarity to blue whale songs in other areas. Recordings of sounds with these characteristics were made opportunistically during the Southern Ocean Research Partnership's recent Antarctic B...

Understanding the dynamics of population recovery is particularly complex when an organism has multiple, remote breeding and feeding grounds separated by one of the longest known migration routes. This study reports on the most comprehensive assessment of humpback whale (Megaptera novaeangliae) movements between remote Antarctic waters south of New...

In understanding the impact of commercial whaling, it is important to estimate the mixing of low latitude breeding populations on Antarctic feeding grounds, particularly the endangered humpback whale populations of Oceania. This paper estimates the degree of genetic differentiation among the putative populations of Oceania (New Caledonia, Tonga, th...

Recent photo-identification and genetic studies have identified at least five discrete breeding populations in Australia and Oceania: western Australia (D), eastern Australia (E (i)), New Caledonia (E (ii)), Tonga (E (iii)), French Polynesia and the Cook Islands (F). Also evident are low levels of intermingling among breeding populations consistent...

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The widely distributed long-finned pilot whale (Globicephala melas) has been reported off the Chilean coast, from Iquique (20°12′S) south to Navarino Island (55°15′S; 67°30′W), but little is known about its biology or ecology in the region. Here, we report on the prey of this species, identified by stomach content analyses from animals stranded on...

Information on the genetic characterisation of humpback whales (Megaptera novaeangliae) wintering off Ecuador (Breeding Stock G) is presented. Mitochondrial DNA was extracted and sequenced from 230 skin samples collected between 2002 and 2008 to establish the genetic diversity of this population. From 182 usable samples, 41 different haplotypes wer...

The occurrence of dwarf minke whales (Balaenoptera acutorostrata subsp.) around the Antarctic Peninsula was examined based on 406 sightings of minke whales recorded during the Chilean Antarctic Scientific Expeditions and other opportunistic cetacean surveys. Identification of the species was made only for the whales sighted in the proximity of the...

A number of studies have described the extension of ice cover in western Patagonia during the Last Glacial Maximum, providing evidence of a complete cover of terrestrial habitat from 41°S to 56°S and two main refugia, one in south-eastern Tierra del Fuego and the other north of the Chiloé Island. However, recent evidence of high genetic diversity i...

We conducted a meta-analysis of the publication statistics for Vols. 1-8 of the Latin American Journal of Aquatic Mammals (LAJAM), the joint scholarly publication of the Sociedad Latinoamericana de Especialistas en Mamíferos Acuáticos and the Sociedad Mexicana de Mastozoología Marina, with the goals of: (a) identifying the main patterns in the auth...

Here we present new records of humpback whale migratory connections between Antarctic Area V and migratory corridors of Australia and the South Pacific based on genotype matching (up to 10 microsatellite loci, with sex and mitochondrial DNA). A total of n = 64 skin biopsy samples were collected by the Australia/New Zealand Antarctic Whale Expeditio...