Diego Rodriguez

Universidad Nacional de Mar del Plata | UNMDP · Instituto de Investigaciones Marinas y Costeras (IIMyC)

Los mamíferos marinos, en particular los cetáceos, dependen del sonido para todos los procesos biológicamente importantes. Los mismos han adaptado tanto su morfología como fisiología para percibir acústicamente su entorno, comunicarse, localizar alimento y protegerse bajo el agua, tanto de manera pasiva como activa. En particular, el delfín nariz d...

Franciscana dolphin (Pontoporia blainvillei) is the most affected dolphin species in the Southwestern Atlantic Ocean. It is classified as Vulnerable A3D by IUCN and SAREM (national level) and only in northern coast of Argentina (Buenos Aires Province) around 400 dolphins are entangled every year in coastal gillnets. However, until now little is kno...

The biggest conservation problem that Franciscana dolphin (Pontoporia blainvillei) are facing nowadays is bycatch. In Argentina has been classified as Vulnerable (SAREM), under the IUCN criteria, and only in northern coast (Buenos Aires Province) around 400 dolphins entangled every year in coastal gillnets. The reason why this dolphin is entangled...

Our main interest is to detect the acoustic presence of franciscana dolphins in an area free of fishing pressure and then compare it with the detections made in areas with active bycatch. To meet that objective, two acoustic detectors (FPODS) were first placed in Chapadmalal (Free fishing zone) and then in two artisanal fishing gillnets in Claromec...

The mammalian heart has been described as a highly evolutionarily conserved structure and the cardiovascular system allometry has been fully studied among many mammalian species, but few of these studies have been focused on marine mammals. Previously reported electrocardiogram (ECG) of anesthetized Southern sea lions (SSL; n = 13) and South Americ...

Niche segregation has been recognized as a valuable mechanism for sympatric species to reduce interspecific competition and facilitate coexistence. The differential use of habitats is one of the behavioural mechanisms that may shape coexistence among marine predators. In this study, we provide a dietary and nutritional assessment of two pinnipeds,...

La ballena jorobada solía tener una presencia esporádica a lo largo de la costa de la Provincia de Buenos Aires (PBA), Argentina. A partir del año 2018 los avistamientos y varamientos han aumentado notablemente. El objetivo del presente trabajo es realizar una recopilación de los registros de ballena jorobada en la PBA, identificando: tendencias, e...

Understanding the role of marine mammals in marine ecosystems provides a context to assess the potential effect of depredation on their prey populations and the structure of communities. Moreover, it helps to figure out the impacts that prey populations suffer from fisheries and other anthropic activities. This understanding can help to foster a ra...

Male-only hauling grounds occur in close association to breeding colonies in several otariids. The occasional use of human-built infrastructure by these groups is also common. We observed permanent male aggregations of southern sea lions, Otaria flavescens, in urban contexts, such as two of the main fishing harbors in Argentina and investigated how...

Elephant seals, Mirounga spp., are highly dimorphic, having different energetic requirements according to age and sex, and foraging in various ecological and oceanographic contexts. Resource partitioning has been shown for the sub‐Antarctic populations of southern elephant seals, M. leonina, where colonies are surrounded by narrow shelves that deep...

Bioaccumulation of Hg and Cd from food is a complex ecological process that has been oversimplified in the past. Common dolphins (Delphinus delphis) provide a powerful model to biomonitor metal concentrations in marine environments worldwide. We combined proportions-based nutritional geometry with metal analysis, stomach content analysis and the pr...

In South-western Atlantic waters, individuals of the southern right whale (SRW) Eubalaena australis spend part of the year (the austral winter and spring) in northern inshore waters where they breed and then migrate to southern feeding grounds during the summer. Mar del Plata (MDP) is located between two main reproductive areas (Península Valdés-Ar...

In Southwestern Atlantic waters, individuals of the southern right whale (SRW) Eubalaena australis spend part of the year (the austral winter and spring) in northern inshore waters where they breed and then migrate to southern feeding grounds during the summer. Mar del Plata (MDP) is located between two main reproductive areas (Península Valdés-Arg...

Communication in Porpoises (Cetacea: Phocoenidae) has been little studied. They usually produce narrow band high frequency clicks for echolocation, which have likely evolved to take advantage of a window of low ambient noise, and/or of the reduced hearing sensitivity of killer whales at these high frequencies (100+ kHz). Evidences for clicks emitte...

Bottlenose dolphins produce varied types of sound, including clicks, whistles, and bursts. We know that dolphins in nature have more click production at night during feeding activities and a peak occur at crepuscular/dawn hours, but dolphins in captivity are involved in several training/feeding sessions per day that are diurnal. To better understan...

La colección biológica del Grupo de Investigación “Biología, Ecología y Conservación de Mamíferos Marinos” del Instituto de Investigaciones Marinas y Costeras (IIMyC, UNMdP- CONICET, Argentina), reúne material óseo, diversos órganos, datos biométricos y fotográficos de mamíferos marinos colectados principalmente en la costa de la provincia de Bueno...

In Southwestern Atlantic waters, individuals of the Southern Right Whale (SRW) Eubalaena australis travel each year from their southern summer feeding grounds to their northern calving areas: Península Valdés (PV-Argentina) and Santa Catarina (SC-Brazil). The coast of Mar del Plata (MDP) is located between these two main reproductive areas. The pur...

La marsopa espinosa es un cetáceo costero robusto y de pequeña talla endémica de Sudamérica, distribuido de forma continua entre el sur de Brasil en el Atlántico hasta el norte de Perú en el Pacífico. En la provincia de Buenos Aires son raros los registros y escasos sus varamientos. El objetivo de este trabajo fue describir por prime-ra vez la diet...

El objetivo de este trabajo fue describir los hábitos tróficos de ambas especies en la región costera bonaerense, a partir del análisis del contenido gastrointestinal de ejemplares varados.

Signature whistles are stereotyped and individually distinctive acoustic signals used as individual recognition calls, for maintaining group cohesion and during stressful situations. Here, it’s proved the occurrence of stereotyped whistles and how it changes, by an isolated adult female of short-beaked common dolphin (Delphinus delphis) kept in reh...

El Pingüino de Magallanes (Spheniscus magellanicus) es una de las aves marinas más abundantes de nuestro país y la más numerosa del género Spheniscus. La Tasa Metabólica de Reposo (TMR) se estima que representa el 25%-30% del gasto diario energético de las aves. No hay estudios detallados en esta especie, como si lo hay en otros miembros de la fami...

The goal of this study was to characterize the Electrocardiogram (ECG) of anesthetized South American Fur Seals (SAFS). Nineteen wild SAFS females were anesthetized with isofluorane at Isla de Lobos (Uruguay). ECG recording was performed at ventral recumbence following standardized procedures. All animals showed normal sinus rhythm. Amplitude and d...

ABSTRACT Signature whistles are stereotyped and individually distinctive acoustic signals used as individual recognition calls, for maintaining group cohesion and during stressful situations. Here, it’s proved the occurrence of signature whistles and how it change, by an isolated adult female of short-beaked common dolphin (Delphinus delphis) kept...

The goal of this study was to classify dives of free-ranging female southern elephant seals Mirounga leonina from Península Valdés, Argentina, during their 2 mo post-breeding migration. Classifications were based on 3-dimensional movements and video-recorded observations from 13 797 dives obtained by attaching video and data recorders to the backs...

The foraging strategies of gestating female elephant seals (Mirounga leonina) from Península Valdés, Patagonia, were assessed by analyzing the values of stable isotopes of carbon (C) and nitrogen (N) from whiskers of 60 weanlings as a proxy for maternal spatial niche utilization. The data were combined with isotopic values and at-sea satellite loca...

ABSTRACT Signature whistles are stereotyped and individually distinctive acoustic signals used as individual recognition calls, for maintaining group cohesion and during stressful situations. Here, it’s proved the occurrence of stereotyped whistles and how it changes, by an isolated adult female of short-beaked common dolphin (Delphinus delphis) ke...

The goal of this study was to test transthoracic echocardiography as a method to characterize heart morphology and function in the southern sea lion (SSL) (Otaria flavescens) for health evaluation. Four clinically healthy captive SSLs (mean weight 110 ± 17.5 kg) were trained to be examined by transthoracic echocardiography at Mar del Plata Aquarium...

In this paper, we examined the ingestion of marine debris (MD) in South American fur seals (SAFS), Arctocephalus australis, found dead in coastal beaches of northern Argentina and southern Brazil. Seven percent of 133 SAFS analyzed presented marine debris in their stomach (n = 10), with no differences between sampling countries (Brazil n = 7, Argen...

Knowledge of growth patterns of an animal species is fundamental to understand their life history. This information is also used to help define population boundaries of threatened cetaceans, such as the Franciscana dolphin, Pontoporia blainvillei . A total of 108 Franciscana dolphins incidentally captured in artisanal fishing nets in estuarine and...

Disentangling the intricacies governing prey selection and dietary breadth in wild predators are important for understanding their role in structuring ecological communities and provides critical information for the management and conservation of ecologically threatened species. Here, we combined dietary analysis, nutritional composition analysis o...

The Franciscana dolphin Pontoporia blainvillei is characterized by a long rostrum, a feature that is shared with the families formerly classified as river dolphins (Pontoporiidae, Platanistidae, Iniidae, Lipotidae). Although there are occasional reports on the existence of beak deformations, very little published information exists describing this...

Levels of zinc (Zn), copper (Cu), potassium (K), calcium (Ca), magnesium (Mg), and phosphorus (P) in plasma of Otaria flavescens females (n = 29) were evaluated. Reference intervals were established for each element, being the first report for this species.

During the last centuries, populations of marine megafauna—such as seabirds, turtles, and mammals—were intensively exploited. At present, other threats such as bycatch and pollution affect these species, which play key ecological roles in marine ecosystems as apex consumers and/or nutrient transporters. This study analyses the distribution of six m...

Knowledge of the real size of any wild population is an essential tool to take management and conservation measures and even more so when the population studied may have potential conflicts with humans. Because of this, the objective of this study was to estimate the population size of two South American sea lion male haul-outs using mark-resightin...

Southern sea lions (Otaria flavescens; SSL) have a polygynous mating system and a prolonged social-sexual maturation period for males. Male haulouts are common in this species, with some very distant from central breeding rookeries, although the functions of these aggregations are not clearly understood. To estimate the potential connectivity betwe...

El lobo marino de un pelo (Otaria flavescens) es el pinnípedo más común de la costa Argentina y el único sudamericano que forma colonias portuarias estables, como las observadas en Necochea y Mar del Plata. En estas colonias no reproductivas, de machos, los animales alternan períodos de permanencia en tierra y en mar abierto con duraciones aproxima...

El objetivo de este trabajo es presentar los resultados de la revisión de la colección ósea de Mamíferos Marinos perteneciente a la Universidad Nacional de Mar del Plata (UNMdP) La revisión consistió en la cuantificación del material óseo de cetáceos y pinnípedos y su clasificación al menor nivel taxonómico posible. La información complementaria ta...

Objectives: The goal of this study was to characterize for the first time the electrocardiogram (ECG) of the southern sea lion (SSL) Otaria flavescens. Animals, materials and methods: Thirteen wild SSL females were captured at Isla de Lobos (Uruguay) and anaesthetized with isoflurane. Electrocardiographic recording was performed on anaesthetized...

This article presents the results of a summer survey of marine mammal occurrence at the BrazilMalvinas Confluence in the Argentine Sea shelf break. A total of 61 marine mammal sightings were recorded. The most frequent species recorded were South American fur seals (Arctocephalus australis; 75.4%; 78-4670m),followed by sperm whales (Physeter macroc...

The South American Fur Seal, Arctocephalus australis, was severely depleted during the 18th century. This work updates information on distribution, abundance, seasonal movements, and genetic structure along the southwestern South Atlantic. Its distribution in Argentine waters includes nineteen rookeries on the Patagonian coast, Isla de los Estados...

The present study provides information about the diet composition of franciscana dolphin, Pontoporia blainvillei, from southern Buenos Aires coast, Argentina. From 2003 to 2011 we collected 66 franciscana dolphins that were incidentally entangled in artisanal fishing nets. We analyzed the stomach contents and estimated the prey size in order to eva...

The franciscana dolphin (Pontoporia blainvillei) is a small coastal dolphin endemic to the Southwestern Atlantic Ocean. Incidental captures in fishing gillnets is possibly the greatest conservation concern for this species and occurs within most of its geographical distribution. The aim of this paper was to determine the biological parameters o...

Metallothioneins are signals of metal exposure and widely used in biomonitoring. Franciscana dolphin is an endemic cetacean from the Southwestern Atlantic Ocean, classified as Vulnerable A3d by the IUCN. Metallothionein, copper and zinc in Franciscana were assessed in two geographic groups; one inhabits La Plata River estuary, anthropogenically imp...

Hair bleaching marking technique in South American sea lions Otaria flavescens: Description and evaluation of method. The aim of this paper is to describe and evaluate the use of the hair discoloration method in South American sea lions, with an emphasis on its advantages and its potential use in future studies. For marking, stamp removable letters...

Larvae of the genus Pseudoterranova constitute a risk for human health when ingested through raw or undercooked fish. They can provoke pseudoterranovosis in humans, a fish-borne zoonotic disease whose pathogenicity varies with the species involved, making their correct specific identification a necessary step in the knowledge of this zoonosis. Larv...

Birth, lactation, and maternal investment have been described and measured in many species of terrestrial and marine mammals that nurse their young on land such as pinnipeds, aquatic mustelids, and polar bears (Siniff & Ralls, 1991; Derocher & Stirling, 1995; Trillmich & Weissing, 2006). Because of their fully aquatic life cycle, information about...

The aim of this paper is to describe and evaluate the use of the hair discoloration method in South American sea lions, with an emphasis on its advantages and its potential use in future studies. For marking, stamp removable letters and numbers were used, connected to an extensible rod. The bleached marks obtained had a maximum duration of 347 days...

We measured the metabolic rate of nineteen wild and three captive, trained Southern sea lions (Otaria flavescens, Shaw 1800) during three behavioral states: resting in air (_ V O2 rest air), resting in water (_ V O2 rest water) and sub-merged swimming (_ V O2 sub swim) using open flow respirometry. We then used these values to estimate total cost o...

a b s t r a c t At-sea behavior and effects of hydrographic conditions on the pelagic habitat use of South American fur seals (Arctocephalus australis) seasonally inhabiting the surrounding waters of shallow rocky reefs off Punta Mogotes (Mar del Plata, Argentina) were analyzed integrating geographic locations of fur seal groups (FSGs) with coastal...

Permanent non-breeding Southern sea lion (Otaria flavescens) male rookeries are found in Mar del Plata (38º 02’ S, 57º 31’ W) and Quequén (38º 35’ S, 58º 42’ W) harbors in northern Argentina. These rookeries are located in an intermediate area between two main breeding sites (Uruguay and Patagonia) with a gap of 1,000 kilometers, and a significant...

resuMen A partir del análisis de 73 cráneos de Arctocephalus australis se deter-minó el patrón y orden de cierre de 12 suturas craneanas utilizando cuatro estadios de cierre sutural (1: sutura abierta, 2: sutura menos del 50 % cerrada, 3: sutura más del 50 % cerrada y 4: sutura cerra-da). Las suturas presentaron patrones de cierre diferentes según...

Sources of information used to estimate total number of marine species for different taxa of the Patagonian Shelf region of South America. (0.06 MB DOC)

Summary of literature sources on marine biodiversity for the non-coastal Brazilian deep-sea marine realms: (1) slope, (2) seamounts and oceanic islands, and (3) abyssal plains. (0.09 MB DOC)

Diversity, state of knowledge, and expertise of all taxonomic groups within the Tropical West Atlantic region of South America. Sources of the reports: databases, scientific literature, books, field guides, technical reports. State of knowledge classified as: 5 = very well known (>80% described, identification guides <20 years old, and current taxo...

Diversity, state of knowledge, and expertise of all taxonomic groups within the Humboldt Current region of South America. Sources of the reports: databases, scientific literature, books, field guides, technical reports. State of knowledge classified as: 5 = very well known (>80% described, identification guides <20 years old, and current taxonomic...

Diversity, state of knowledge, and expertise of all taxonomic groups within the Patagonian Shelf region of South America. Sources of the reports: databases, scientific literature, books, field guides, technical reports. State of knowledge classified as: 5 = very well known (>80% described, identification guides <20 years old, and current taxonomic...

Sources of information used to estimate total number of marine species for different taxa of the Tropical East Pacific region of South America. (0.05 MB DOC)