Argentinean Waters Research Articles

Exporting the problem: Issues with fishing closures in seabird conservation

Fisheries management may impact on a range of seabirds’ traits such as foraging behavior. There is an extensive hake fishing closure in Argentine waters (HFC) where trawling is banned. The concentration of fishing effort in the boundary of this area triggered the question of a potential negative effect of seabird bycatch in such area. The distribution of seabirds attending vessels and their bycatch rates was explored as well as the foraging behavior of Black-browed albatrosses (BBA, Thalassarche melanophris) and Southern Giant Petrels (SGP, Macronectes giganteus) in relation to the HFC. For this, 55 satellite transmitters were deployed on the birds and discrete behavioral mode was inferred using state-space models. Seabird attendance at trawlers and bycatch data were obtained from on-board observers. The spatial distribution of the birds’ bycatch was concentrated in the boundary of the HFC and the distance to the boundary had a significant effect on the interactions. The spatial modeling of seabird attendance revealed a similar pattern with core areas in the margins of the HFC. The bulk of the core foraging areas of BBAs and SGPs were concentrated in waters adjacent to the HFC. Besides, the time spent foraging in the boundaries of the HFC was greater than inside the HFC. The study highlights that the “exporting effect” due to the concentration of fishing effort and seabird foraging in bordering areas may increase seabird bycatch in the neighboring waters. Hence, the design of management measures for seabird bycatch should contemplate regulations to address these negative side effects.

Making the Indigenous Desert from the European Oasis: The Ethnopolitics of Water in Mendoza, Argentina

AbstractThis article analyses the ethno-politics of water in Argentina at the high point of European immigration, the first three decades of the twentieth century. Focusing on the drying of the Guanacache wetlands, located in the wine-producing region of Cuyo, we show how national and provincial ideologies based on ‘whitening’ and ‘civilisation’ shaped policies that favoured European immigrants at the expense of autochthonous populations in the geographic and social struggle for irrigation water. A large-scale redistribution of water resources drove the indigenisation of indigenous and criollo populations and the desertification of their land.

The southernmost range limit for the hidden angelshark Squatina occulta

Angelsharks (Genus Squatina) are distributed in the southern Southwest Atlantic Ocean between southeastern Brazil and central Patagonia. The endangered hidden angelshark Squatina occulta is reported in the literature as ranging from Espirito Santo, Brazil to Southern Uruguay. Its presence in Argentine waters has been suspected but not verified so far. This study describes and analyzes a specimen of S. occulta found in Puerto Quequen 38° 40′S - 58° 50′W, Buenos Aires Province, Argentina. An immature male of 578 mm total length and 1,450 g was collected from commercial landings of the bottom trawl fishery of Puerto Quequen. The specimen exhibited the coloration pattern, dermal denticle distribution, and tooth formula characteristic of S. occulta. Squatina guggenheim and S. argentina are already known to occur off Puerto Quequen. The present finding confirms the presence of a third species of angelshark in Argentina and constitutes the southernmost record of S. occulta.

Namuncurá Marine Protected Area: an oceanic hot spot of benthic biodiversity at Burdwood Bank, Argentina

The first open-sea (non-coastal) Marine Protected Area (MPA) in Argentina was created in 2013 (and named “Namuncura”), at Burdwood Bank, an undersea plateau located about 200 km south from Malvinas/Falkland Islands, SW Atlantic Ocean. This contribution represents the most recent and complete checklist of benthic organisms (mainly mega and macrofauna) that summarized 240 taxa collected at three sites in the mentioned area. The benthic richness here documented largely exceeds the values coming from other productive areas in Argentinean waters. Faunistic composition was different among the sites, although several species were shared. Bryozoans presented the highest richness compared to the other groups, followed by mollusks and sponges. These data represent valuable information and a very helpful starting point for incoming research, conservation efforts and management. It is essential to establish the spatial distribution of indicator taxa, like corals, sponges and bryozoans, to better attempt at the protection of benthic biodiversity in this rich Argentinean marine system. This is a key issue considering the notable extension of the MPA compared to other areas in Argentina, the bathymetric variations, particular oceanographic conditions and different fishing circumstances within the area.

First report of predation by a small shark on the invasive rapa whelk Rapana venosa (Valenciennes, 1846) in Argentinean waters

Fil: Bonelli, Ana Gabriela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografia Naval; Argentina

Marine Bivalves from the Argentine Coast and Continental Shelf: Species Diversity and Assessment of the Historical Knowledge *

Abstract: Bivalves are one of the most abundant groups of invertebrates in many benthic communities. From 1817 to date, numerous contributions have dealt with the Argentine fauna of marine bivalves. Despite this, at present, there is no a text summarizing the currently available information on this group in Argentine waters. The present contribution aims to provide a synthesis of the current state of knowledge of systematics, geographic distribution, biology, and ecology of the living marine and estuarine species of bivalves from the Argentine coast and its shelf and, based on this information, to analyze the species diversity of these areas. For that, 225 publications, including results of scientific expeditions, systematic revisions, description of new species, new distributional records, checklists, compilations on the diversity for particular areas, and contributions dealing with biological and ecological information, were surveyed. As part of this study, 277 nominal species of bivalves were found rep...

Quantification of human infection risk caused by rotavirus in surface waters from Córdoba, Argentina

Fecal contamination of water is a worrying problem because it is associated with the transmission of enteric pathogenic microorganisms that can cause many infectious diseases. In this study, an environmental survey was conducted to assess the level of viral contamination by viable enterovirus and rotavirus genome in two recreational rivers (Suquía and Xanaes) of Córdoba, Argentina. Quantitative microbial risk assessment (QMRA) was calculated to estimate the risk of rotavirus infection. Water sampling was carried out during a one-year period, the presence of total and fecal coliforms was determined and water samples were then concentrated for viral determination. Cell culture and indirect immunofluorescence were applied for enterovirus detection and RT-qPCR for rotavirus quantification. Coliform bacteria levels found in Suquía River often far exceeded the guideline limits for recreational waters. The Xanaes exhibited a lower level of bacterial contamination, frequently within the guideline limits. Enterovirus and rotavirus were frequently detected in the monitoring rivers (percentage of positive samples in Suquía: 78.6% enterovirus, 100% rotavirus; in Xanaes: 87.5% enterovirus, 18.7% rotavirus). Rotavirus was detected at a media concentration of 5.7×105 genome copies/L (gc/L) in the Suquía and 8.5×100gc/L in the Xanaes. QMRA revealed high risk of rotavirus infection in the Suquía, at sampling points with acceptable and non-acceptable bacteria numbers. The Xanaes showed significantly lower health risk of rotavirus infection but it proved to be a public health hazard. The viral occurrence was not readily explained by the levels of bacteria indicators, thus viral monitoring should be included to determine microbiological water quality. These findings provide the first data of QMRA for recreational waters in Argentina and reveal the need for public awareness of the health implications of the use of the river waters.

South American sea lions (Otaria flavescens) and killer whales (Orcinus orca) attending chub mackerel (Scomber japonicus) commercial trawl fisheries over the Patagonian Shelf: a first report

Killer whale-seal interactions have been reported for almost all pinniped species globally. However the literature on offshore interactions between killer whales and sea lions is rare for the South Atlantic, particularly in Argentine waters. Here we report for the first time the harassment of a South American sea lion (Otaria flavescens) by killer whales (Ornicus orca) while attending commercial fishing vessels in offshore national waters and describe a novel sea lion antipredator behaviour. These observations were made during an ongoing survey to assess seabird-fisheries interactions in the commercial trawl fishery off Argentina.

Finding of a skull of Pseudorca crassidens in Caleta de Los Loros, Rio Negro Province, Argentina

The false killer whale, Pseudorca crassidens, exhibits one of the widest and most continuous distributions among cetaceans. However, basic information about its biology is poorly known due to the low frequency of sightings and its offshore habits. Moreover, most of the knowledge on this species has been obtained from stranded animals. On 3 March 2012, in the proximity of a colony of South American sea lions (Otaria flavescens) located at Caleta de los Loros, Río Negro Province, Argentina (40o59’S, 64o14’W), a cetacean skull was found in the intertidal zone. The specimen was later identified as P. crassidens. The present note reports a new record of false killer whale in the continental shelf waters of Argentina and provides new data on the distribution and skull morphometrics of the species.

Occurrence and profiles of lipophilic toxins in shellfish harvested from Argentina.

The presence of phytoplankton responsible for the production of lipophilic marine biotoxins is well recognised throughout parts of South America. To date, the quantitation of lipophilic toxins in Argentinean shellfish has been limited to select and highly focussed geographical studies. This work reports the analysis for lipophilic marine biotoxins in shellfish harvested across five regions of Argentina between 1992 and 2012. LC-MS/MS analysis was used for the quantitation of all regulated lipophilic toxins. High concentrations of okadaic acid group toxins were quantified, with a clear dominance of the parent okadaic acid and more than 90% of the toxin present as esters. Results showed DSP toxins in shellfish from the Buenos Aires Province during 2006 and 2007, earlier than previously described. There was also strong evidence linking the presence of okadaic acid to human intoxications. Other lipophilic toxins detected were yessotoxin, pectenotoxin-2 and 13-desMeC spirolide. With evidence published recently for the presence of azaspiracid producers, this work reports the detection of low concentrations of azaspiracid-2 in shellfish. As such the data provides the first published evidence for yessotoxins and azaspiracids in Argentinean shellfish and further evidence for the continuing presence of lipophilic marine toxins in Argentinean waters.

First report of the black gemfish Nesiarchus nasutus (Perciformes: Gempylidae) in Argentinean waters.

The gempylid Nesiarchus nasutus is reported for the first time from Argentinean waters, the southernmost occurrence of the species in the Southwestern Atlantic. This suggests that the fluctuating environmental characteristics of the area would be proper for the presence of tropical and subtropical species.

A second documented record of Spectacled Petrel Procellaria conspicillata in Argentine waters

The Spectacled Petrel Procellaria conspicillata is endemic to Inaccessible Island, in the Tristan da Cunha group (central South Atlantic). The species is considered an occasional visitor to Argentina and there are few records of the species in national waters. On 13 February 2014, two birds were observed (and photographed) 89 nautical miles southeast off Buenos Aires Province at 38°55'S, 56°00'W. This record represents the second documented record of Spectacled Petrel for Argentina.

The hermit crab Sympagurus dimorphus (Anomura: Parapaguridae) at the edge of its range in the south-western Atlantic Ocean: population and morphometry features

Sympagurus dimorphus is one of the 12 hermit crab species recorded for Argentinean waters. Despite the high abundance registered in some scallop fishing grounds, its biology remains little known. In the present study, we analysed some population features of S. dimorphus living in symbiosis with Epizoanthus paguricola from a series of samples taken in the Argentine Sea, south-western Atlantic Ocean. Our results showed that S. dimorphus was commonly found from 40ºS to lower latitudes, in a patchy distribution along the shelf-break front. The overall sex ratio was 1:1. The smallest ovigerous female measured 6 mm in cephalothoracic shield length and this size was used as parameter to define the size of juveniles. The sex ratio size class pattern corresponded to Type IV or anomalous curve. S. dimorphus is a dimorphic species, as evidenced by the larger size of the males and the positive allometric growth of the right cheliped. The species also showed asymmetry, with the left uropod always larger than the right one. To the best to our knowledge, this is the first report on population features and relative growth for a member of the genus, based on long-term sampling. This species presents a patchy distribution along the shelf-break of Argentina. Its density tended to decrease over the five-year sampling period regarding the recruitment of hermits associated with colonies of zoanthids. In addition, the relatively homogeneous nature of this refuge does not seem to influence the growth of the hermit crab, which presents sexual dimorphism in relation to the sex/size conditions.

Spatial genetic structure of dusky dolphin, Lagenorhynchus obscurus, along the argentine coast: preserve what scale?

Abstract The dusky dolphin (Lagenorhynchus obscurus) represents one of the most abundant species of small cetacean in Argentine waters. During the 1980s and 1990s, high levels of incidental mortality in purse and trawl fisheries were documented, and in recent decades tourism activities have been added as a potential source of disturbance. The study objectives were to identify spatial genetic structure and regional genetic patterns of dusky dolphins along the Argentine coast. The variation of 413bp of the control region of 119 individuals over six locations spread along 2800 km (38°40'S to 54°30'S) was examined. Spatial genetic analyses, SAMOVA, genetic landscape shapes and autocorrelation analyses were conducted. The most probable configuration was K=2, island population vs. continental populations (FCT = 0.774) and the spatial autocorrelation analysis showed a strong regional genetic structure, defining an operational unit at < 50 km. The results provide valuable information that should be taken into account in the development of conservation strategies and management of the species; making the efforts focus on conserving vulnerable dusky dolphin groups by protecting their preferred coastal shallow habitat and by monitoring and regulating the dolphin watching and fishing activities, acting upon local populations along the Argentine coast. Copyright © 2015 John Wiley & Sons, Ltd.

Status, population trend and genetic structure of South American fur seals, Arctocephalus australis, in southwestern Atlantic waters

AbstractThe South American fur seal (SAFS), 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, and islets of the Beagle Channel. Censuses were carried out in rookeries from Isla Escondida to Isla de los Estados from 1996 to 2014. The largest concentrations are found in Chubut, (4,500–15,500 seals) and Isla de los Estados (4,500). Pups were recorded on Isla Escondida, Rasa, and Isla de los Estados. An increasing number of SAFS were recorded in northern Patagonia, including seals marked in Uruguay. Skin samples were taken from southern Brazil to Tierra del Fuego in order to evaluate population structure and demographic trends. Genetic results indicated no population subdivisions (Φst = −0.0292, Fst = −0.00716, P > 0.05). Bayesian skyline plots constructed for the entire data set indicated evidence of rapid population expansion discernible in Nef between the last 20,000 and 17,000 yr. Genetics results and observation data from marked fur seals support the hypothesis of ancient gene flow and a single Atlantic population. Therefore, SAFS should be managed under international and integrated conservation policies.

Outbreak of a neurotoxic side-gilled sea slug (Pleurobranchaea sp.) in Argentinian coasts

Since 2009 we have been registering the outbreak of an unknown side-gilled sea slug of the genus Pleurobranchaea in coastal waters of Argentina, southwestern Atlantic Ocean. Examination of both external macroscopic features and internal structures via electron microscopy did not allow us to conclusively identify the species. Nevertheless, since Argentinian specimens closely resemble Pleurobranchaea maculata (a species native from Australia and New Zealand known to contain a potent neurotoxin) we performed a bioassay in our specimens, which was positive for neurotoxins. The presence of this pleurobranch in Argentinian waters is of concern beyond the ecological effects of the outbreak of a marine predator and requires urgent attention. This work provides a guide to distinguish between this unidentified species and the sympatric cryptogenic Pleurobranchaea inconspicua, based on features that are readily observable in fresh and preserved specimens. We discuss the potential effects of this outbreak on local communities.

The Implementation of the Human Right to Water in Argentina and Colombia

The article deals with the recognition of access to water as a human right in various international legal instruments offering a comparative perspective from the practice in Argentina and Colombia. The essay explores the human right to water providing with new insights about the enforceability (referred to as “justiciability”) of the right to water in light of recent rulings issued by the Colombian Constitutional Court and different judgements by Argentine courts. In the analysis the authors further underline main obstacles in the enforcement of the human right to water and the challenges for its protection in the context of climate change.

First record and range extension of the Antarctic coral Flabellum (Flabellum) impensum Squires, 1962 (Cnidaria: Scleractinia) in Argentinean coastal waters

The present paper reports the occurrence of the Antarctic coralFlabellum impensumin Tierra del Fuego Province, Argentina, and extends its distribution northwards in the south-west Atlantic Ocean. Nine individuals were found in Argentinean coastal waters in 2014, also representing one of the shallowest records of the species.

Origin and genetic diversity of leatherbacks (Dermochelys coriacea) at Argentine foraging grounds

To conduct conservation of migratory species, such as marine turtles, is important to understand the population structure throughout the entire distribution of the species. We study the genetic composition of the leatherback turtles, Dermochelys coriacea foraging in waters off Argentina by analyzing 763bp sequences of the mtDNA control region in order to determine the nesting origin of these animals. A total of 40 samples were collected from adult leatherbacks (mean 143.5; 180–123cm curved carapace length) captured (10%) in fisheries or encountered as strandings (90%). Based on analysis of mtDNA sequences we detected 4 haplotypes, the most common (n=26) being DC1.1, and the other two rarer DC1.3 (n=4), DC13.1 (n=2), and DC1.4 (n=1). The genetic diversity was evaluated through the haplotype (0, 3712±0, 1000) and nucleotide diversities (0, 000521±0, 000553). Bayesian Mixed Stock Analysis (MSA) showed that the Buenos Aires foraging leatherbacks come primarily from the West African rookeries (Ghana and Gabon, mean estimate=69% and 14% respectively). MSA results are consistent with those from mark–recapture studies, since four leatherbacks captured in Argentinean waters were adult females that were originally tagged on the nesting beaches in Gabon, West Africa. Our findings demonstrate the connection between nesting and foraging areas in the South Atlantic and illustrate the importance of the Malvinas ecoregion to the survival of migratory marine vertebrates, such as leatherbacks.

Pleurosigma hinzianum sp. nov. and P. frenguellianum sp. nov. (Pleurosigmataceae, Bacillariophyta) from Argentinean coastal waters, in comparison with P. amara Stidolph and P. elongatum W. Smith

Two new marine diatom species from Argentinean coastal waters, Pleurosigma hinzianum Sterrenburg, Sunesen & Sar, sp. nov. and P. frenguellianum Sunesen, Sterrenburg & Sar, sp. nov., are described. The characters permitting their identification are specified, based on comparison with type material of the morphologically similar species P. amara Stidolph and P. elongatum W. Smith in the light (LM) and scanning electron microscope (SEM). New information on the type material of P. elongatum is presented and its taxonomic concept is emended. The main criteria for separation of the species discussed here are: valve outline, path of the raphe-sternum, raphe angle and angle of intersection of the oblique striae in LM; and external central and terminal raphe fissures, internal details of the central area, external and internal apical structure, and morphology of the hymen-occluded internal pores in SEM. The occurrence of these (and probably other) species in the genus Pleurosigma in net samples is adventitious and not indicative of a true planktonic mode of life.