Coast Of Argentina Research Articles

Toward a Better Understanding of the Native–Nonnative Status ofMytilusMussels in the Southwestern Atlantic: Comparing Pre-European Middens and Modern Populations

ABSTRACT Savoya, V.; Gomez Otero, J., and Schwindt, E., 2015. Toward a better understanding of the native–nonnative status of Mytilus mussels in the southwestern Atlantic: comparing pre-European middens and modern populations. The aim of this study is to determine the degree of similarity of the Mytilus mussels currently found along the Patagonian coast of Argentina to those found in pre-European colonization middens, in order to approach an understanding of whether the former are native or not. An elliptic Fourier analysis between pre-European archaeological (native) and modern mussels (cryptogenic) was performed, and the resulting data were analyzed with multivariate approaches (principal component analysis, discriminant function analysis, and cluster analysis). Our results showed that when all samples belonging to the Patagonian coast were included on a single analysis, modern and archaeological mussels were clustered in two major groups, matching the macroregional marine biogeographic scheme. In addit...

A checklist of the helminth parasites of marine mammals from Argentina

Based on published records and new data accumulated by the authors, we generated a list of the helminth parasites of marine mammals from off the coast of Argentina. We found 49 reports of helminths parasitizing cetaceans and pinnipeds from Argentina from 1952 to 2015. The list includes 54 taxa of helminths (8 acanthocephalans, 24 nematodes, 11 cestodes and 11 trematodes) associated with 18 species of cetaceans and 5 species of pinnipeds. Most of the records represent adults (5 acanthocephalans, 16 nematodes, 6 cestodes and 11 trematodes), followed by larvae (10 nematodes and 3 metacestodes) and juveniles (4 acanthocephalans and 2 cestodes). The checklist contains 24 named species (5 acanthocephalans, 8 nematodes, 4 cestodes and 7 trematodes) and 30 undetermined helminth taxa (3 acanthocephalans, 16 nematodes, 7 cestodes and 4 trematodes). The present account contains a parasite/host lists and information on the habitat, developmental stage and distribution of the parasites listed, repositories of their type and voucher specimens and references. A host-parasite list is also presented. The data compiled on the helminth of marine mammals from Argentina in the present study revealed gaps in the knowledge of their taxonomic identification, composition, distribution, host specificity and life cycles. These gaps are also briefly discussed in order to provide an outline for future research.

Are stocks of immature loggerhead sea turtles always mixed?

Sea turtles perform extensive migratory movements between feeding, developmental and nesting areas. Developmental areas for immature loggerheads turtles (Caretta caretta) are usually composed of individuals from multiple distant rookeries. Thus, impacts on such stocks usually affect multiple colonies, which require international efforts for conservation. This study describes the molecular genetic composition of the more austral foraging and developmental grounds of loggerhead sea turtles in the Atlantic Ocean and infers the possible origin and dispersal patterns of the species. Analyses were performed using shorter (380bp) and larger (760bp) sequences of the control region of mitochondrial DNA (mtDNA) from 24 samples of bycatch and 37 samples of stranded loggerhead sea turtles on the coast of the province of Buenos Aires, Argentina. All specimens (N=61) were adults and sub-adults (mean±standard deviation curved carapace length CCL=68.3±13.4cm; range: 52.0 to 107.0cm, N=41 individuals measured). Both shorter and longer mtDNA sequence analysis showed that in the foraging grounds of the Argentinean coast only haplotypes from Brazilian nesting areas (CC-A4=98% and CC-A24=2% for shorter sequences, and CC A4.2=81%, CC A4.1=17% and CC A24.1=2% for longer sequences) were found. The homogeneous stock located relatively close to the rookery where individuals originated contradicts the paradigm of immature loggerhead sea turtles forming mixed stocks in foraging and developmental areas. The conservation of the stock in coastal areas of Argentina could benefit the nesting population in the nearby Brazilian rookeries, and could be achieved by conservation actions between these two countries, as well as Uruguay in between.

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.

Transfer processes drive population dynamics of kelp gull colonies in Patagonia: Implications for management strategies

The dispersal of individuals among breeding sites is considered to be one of the key processes in seabird population dynamics. The kelp gull (Larus dominicanus) is the most abundant gull in coastal Argentina, although its population dynamics in the region remains poorly understood. This article aims to address aspects of kelp gull demography along a wide coastal sector (~1800 km) in northern Patagonia to improve our understanding of population changes and contribute to the design of management strategies and monitoring programmes. Modelled scenarios suggest that annual increases of 10–20% are high for the species, and 29% of 62 evaluated colonies presented growth rates within this high reference range. Transfer processes among colonies (e.g. source–sink) contributed to the growth of at least six kelp gull colonies. These processes have been instrumental in the growth of small, and in some cases recently established colonies, which had generally higher growth rates and were found near large and long-established colonies. These are the first studies of kelp gull demography on the coasts of Argentina aimed at understanding the population dynamics of this species in a metapopulation context.

Sperm ultrastructure in two species of Brachidontes (Bivalvia, Mytilidae) from the south-western Atlantic Ocean

Brachidontes rodriguezii and Brachidontes purpuratus have a wide geographic distribution along the Argentinean coast. Both species are abundant in the intertidal area of rocky shores. We used transmission electron microscopy to study the spermatogenesis of B. rodriguezii and the structure of mature spermatozoa from B. rodriguezii and B. purpuratus. Our results show that spermatogenesis in B. rodriguezii is very similar to that reported in other mytilids. The spermatozoa of both Brachidontes are of the primitive or ect-aquasperm type showing a spherical nucleus capped by a conical acrosome with an anterior extension. The chromatin was electron-dense, homogeneous and compact. The mid-piece region consisted of 5 spherical mitochondria grouped in a ring around a pair of short cylindrical centrioles. The flagellum exhibit the typical 9 + 2 microtubule structure. Studies of spermatozoa ultrastructure are considered a useful tool in bivalve phylogeny. Characters in the spermatozoa morphology of these two species were observed and a brief discussion about the sperm morphology along the distribution of both species is presented. We suggest that the acrosome complex presents the most significant differences between both species.

Nutrient allocation in the gonads of the sea urchin Arbacia dufresnii in different stages of gonadal development

This study reports nutrient allocation in different stages of gonadal development for two populations of the sea urchin Arbacia dufresnii off the Patagonian coast of Argentina (Nuevo Gulf and San Jorge Gulf). The biochemical composition of gonads was used to assess nutrient allocation by measuring ash, soluble protein, lipid and trichloroacetic acid-soluble carbohydrate concentrations, and absolute contents over a 24-month period. Reproductive output in terms of energy was calculated for females. Results were correlated with histological stage of the gonads. Soluble proteins were the main component for the Nuevo Gulf population while unmeasured organic material (i.e. insoluble proteins and nucleic acids, especially in testes) was prevalent in gonads from San Jorge Gulf. Soluble protein and lipid concentrations followed the gonadal cycle, while carbohydrate concentration was almost negligible, especially in the Nuevo Gulf population. The different patterns in the gonadal cycle in the two populations were reflected in the biochemical composition of gonads. Concentrations and contents of the biochemical components and reproductive output were higher in the population from San Jorge Gulf owing to the larger size of gonads and gametes. These findings contribute to the better understanding of the plasticity of the reproductive biology of A. dufresnii in different environments.

Panopea abbreviata(Bivalvia: Hiatellidae) in the Southwestern Atlantic Ocean, Taxonomic Revision and Anatomy

The taxonomy and anatomy of the southwestern Atlantic geoduck, Panopea abbreviata Valenciennes, 1839, are revised. Materials from several institutions, as well as new living specimens collected from the coast of Argentina were studied. Type materials of all related nominal species are illustrated. The shell morphology, shell ultrastructure, hinge, ligament and mantle cavity organs are described. The symbiotic relationship with the nemertean Malacobdella arrokeana, attached to host mantle tissues, is mentioned. Panopea abbreviata is abundant in the gulfs of northern Patagonia. It occurs in the subtidal zone from 8 to 25 meters deep, deeply buried in the sediment. It has a large thick shell, shortener at the posterior end, with exposed siphons covered by a dark brownish periostracum; a hinge plate characterized by a single cardinal tooth in each valve; and shell ultrastructure with three layers: an outer layer of nearly vertical and composite prisms, a middle, true homogeneous layer, and an inner layer of alternating sublayers of fine complex crossed lamellar and irregular simple prisms. The fused mantle is only interrupted in the pedal gape. Ctenidia and labial palps association belongs to the Category III and ctenidia type C(1). Panopea antarctica is its only synonym. The fossil taxa Panopea truncata, P. inferior, P. hauthali, P. coquimbensis and P. guayacanensis are excluded from the synonymy.

Long-term population trends of the Red-legged CormorantPhalacrocorax gaimardion the Argentine coast

SummaryThe world population of Red-legged CormorantPhalacrocorax gaimardiis reasonably small and has showed rapid declines. In Argentina, this species breeds in 13 localities and is considered as ‘Endangered’ by the national government. In this study, we provide information about population trends of the Red-legged Cormorant on the Argentine coast, between 1990 and 2009. We also discuss whether these trends could be related to sea surface temperature and marine primary productivity, both of which are considered oceanographic factors that can affect breeding seabirds. The long-term trend in the breeding population showed a slight decrease of 1.2% per year. Seven colonies showed an average population change < 1. Periods of stability and increase were identified over the study period, but they were insufficient to compensate for the decreases. The largest colony of Red-legged Cormorants (La Mina, with more than 55% of the entire breeding population) seems to determine the overall population trend. We did not find a direct relationship between the overall number of Red-legged Cormorants and the two oceanographic factors analysed. However, our analysis detected a positive effect of ocean productivity close to the coast on the largest colony at the beginning of the breeding season, suggesting that coastal ocean productivity could be an important factor affecting temporal variations in the Argentinian population.

The Relictual Population of the Purple ClamAmiantis purpurata(L.) in Northern Patagonia (Argentina): The History of a Warm-Temperate-Water Neogene Survivor

Abstract . The purple clam Amiantis purpurata (Lamarck) is a warm-temperate species inhabiting shallow water along the coast from Espiritu Santo (Brazil) to northern Patagonia. It is one of the few survivors of the middle—late Miocene faunal turnover which was characterized by the appearance of new taxa, most of them living now along the Argentinean coast. In order to study the biogeographic history of A. purpurata, a detailed review of its records was carried out. The oldest record of this species is from late Miocene rocks in Uruguay, and it appears that A. purpurata survived because its wide thermal tolerance range allowed larvae to migrate southwards from Uruguay, settling on the southern coast of Buenos Aires Province and San Matias Gulf. The characteristics of this gulf would have favored the development and settlement of the larvae, thus giving rise to the most abundant southern population during the Pleistocene. At the end of the Pleistocene, A. purpurata also survived the Last Glacial Maximum. Du...

A revision of the genus Neogrubea Dillon & Hargis, 1968 (Monogenea: Mazocraeidae): new morphological and molecular data from off the Patagonian coast of Argentina.

The genus Neogrubea Dillon & Hargis, 1968 (syn. Asymmetria Suriano, 1975) is revised based on examination of type- and voucher material, and from new specimens collected from the gills of Seriolella porosa Guichenot and Stromateus brasiliensis Fowler from off Patagonia, Argentina. Morphological comparisons based on light and scanning electron microscopy and molecular data (partial SSU and LSU rDNA sequences) of the monogeneans from off Patagonia suggest that N. seriolellae Dillon & Hargis, 1968 (syns N. stromateae Gibson, 1976, A. asymmetria Suriano, 1975 and A. platensis Rey & Meneses, 1985) is currently the only species of the genus. Neogrubea soni Evdokimova, 1969 is considered a species inquirenda. An emended diagnosis of Neogrubea is presented, and new host and locality records for N. seriolellae are given in detail. Morphological characters of the members of the mazocraeid subfamily Grubeinae Price, 1961 are also discussed.

Invasive polychaete Boccardia proboscidea Hartman, 1940 (Polychaeta: Spionidae) in sewage-impacted areas of the SW Atlantic coasts: morphological and reproductive patterns

Boccardia proboscidea is an alien polychaete species that has been introduced to the Southwestern Atlantic Ocean. This polychaete species has invaded intertidal benthic rocky shores, and builds reefs formed by thousands of individuals per square meter with densities up to 1,500,000 ind.·m−2 in organically impacted sites. This phenomenon was first recorded in Argentina in 2008. This is the first comprehensive study on the morphology, habitat and reproductive biology of B. proboscidea associated with the sewage-induced abrasion platforms on the Argentinean coasts. Adult morphology of B. proboscidea from Mar del Plata is described and a comparison with material from other locations is made. Results showed that B. proboscidea from Mar del Plata, Argentina share the same diagnostic features as those of the individuals from the original description (California). Moreover, the results also indicated that the reproduction of this species involves a poecilogonous development (production of more than one type of offspring with both kinds of larvae) and implicates adelphophagy (nurse egg ingestion). Patterns of larval development varied both within a single brood and among broods of different females. Continuous reproduction of B. proboscidea coupled with a continuous supply of organic matter could explain the possible mechanism that led to the development of reefs.

Genetic population structure in Nacella magellanica: Evidence of rapid range expansion throughout the entire species distribution on the Atlantic coast

Nacella magellanica, the most abundant limpet in the Magellanic biogeographic Province of Argentina and Chile, is characterized by a noticeable variability in shell morphology and color patterns. Ecological as well as evolutionary features make this limpet an interesting species for evolutionary and population genetic studies. Here, arbitrary nuclear molecular markers, inter-simple sequence repeat-PCR, are used to analyze the population genetic structure in 14 localities of N. magellanica along 2900km on the Atlantic coast of the Magellanic Province. We compare the present results, based on nuclear markers, with previous findings of a phylogeographic study that used the mitochondrial COI gene. All the results presented here suggest little genetic structure within N. magellanica, with moderate to high genetic connectivity among populations. The short time elapsed since the expansion of this species plus a possible long larval lifespan and the oceanographic and environmental conditions of the Magellanic Province might explain the lack of genetic structuring and the low levels of genetic differentiation in the species throughout its distribution range along the Argentine coast.

Reproductive system and size maturity of the paddle crab Ovalipes trimaculatus (Brachyura: Portunidae) along the Argentine coast

Fil: Vallina, Micaela Veronica. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina

What is left behind when the lights go off? Comparing the abundance and composition of litter in urban areas with different intensity of nightlife use in Mar del Plata, Argentina

Nightlife activities represents an important source of urban litter; the latter often being left behind or abandoned in public places and streets. Mar del Plata is a very important city on the Atlantic coast of Argentina and is the main tourism destination in the South Atlantic region of South America. However, few studies on urban litter related to nightlife activities have been conducted in the area. Here we assessed (i) the abundance and composition of litter, and (ii) the spatial and temporal variations of its abundance, diversity, richness and evenness in urbanized areas with different intensity of nightlife activities from April 2008 to March 2009. An overall of 13,503 items were counted. Around 92% of the total litter was comprised by cigarette butts, papers and plastics. We found significant spatial differences in the abundance of litter between sampling sites, with the greatest amounts of litter at the Alem site followed by the Hipólito site (both with an intensive nightlife activity) compared with the Chauvin site (a quiet high-income neighborhood). The composition of litter of the Alem and the Hipólito sites was relatively similar and both sites differ with respect to the Chauvin site. Cigarette butts, papers, and plastics were the items that contributed most to the dissimilarity between sampling sites. The diversity of litter was the single community parameter that significantly differed from the other seasons. We discussed the potential effect of nightlife activities on the amounts and quality of urban litter in the city of Mar del Plata.

Horizontal transport, mixing and retention in a large, shallow estuary: Río de la Plata

We use field data and a high-resolution three-dimensional (3D) hydrodynamic numerical model to investigate the horizontal transport and dispersion characteristics in the upper reaches of the shallow Rio de la Plata estuary, located between the Argentinean and Uruguayan coasts, with the objective of relating the mixing characteristics to the likelihood of algal bloom formation. The 3D hydrodynamic model was validated with an extensive field experiment including both, synoptic profiling and in situ data, and then used to quantify the geographic variability of the local residence time and rate of dispersion. We show that during a high inflow regime, the aquatic environment near the Uruguayan coast, stretching almost to the middle of the estuary, had short residence time and horizontal dispersion coefficient of around 77 \(\mathrm {m}^{2}\,\mathrm {s}^{-1}\), compared to the conditions along the Argentinean coastal regime where the residence time was much longer and the dispersion coefficient (40 \(\mathrm {m}^{2}\,\mathrm {s}^{-1}\)) much smaller, making the Argentinian coastal margin more susceptible for algae blooms.

Two new species of Halichondrida (Demospongiae) and the first record of Phycopsis and Ciocalapata for Brazil.

Two new species of the genera Phycopsis and Ciocalapata are described from the shallow waters off the Brazilian coast. This is the first record of Phycopsis in South Atlantic, with Phycopsis styloxeata sp. nov. being the only species of the genus that presents three categories of spicules: two of styles and one of oxeas. Ciocalapata, here represented by Ciocalapata minuspiculifera sp. nov., displays smaller oxeas and styles when compared to its congeneric C. amorphosa (Ridley & Dendy, 1886). The definition of this genus was modified and its geographical and bathymetric distributions now extend from the coast of Argentina to the northeastern coast of Brazil (state of Bahia) and from deep (1.097 m) to shallow (14-20 m) waters, respectively.

Marine Holocene microgastropods of northeast Buenos Aires Province, Argentina

Marine micromolluscs, especially gastropods, are found in Quaternary marine deposits on the coast of the province of Buenos Aires. In this study, the microgastropods from Holocene beach ridges of northeast Buenos Aires Province are described. Eight localities were analyzed in the SE margin of the Río de la Plata between Berisso and Cerro de la Gloria, Samborombón Bay, in which 5391 individuals of 11 species were recovered. Registration of two species of the subfamily Triphorinae Gray, 1847 not found before for the Quaternary of Argentina, is reported. The species Parvanachis isabellei (d'Orbigny, 1839), Iselica anomala (Lea, 1843), Turbonilla paralaminata Castellanos, 1982 and Turbonilla farinatiae (Pimenta and Absalão, 2004) were first recorded in Quaternary marine deposits of the study area, hence extending their geographical distribution during the Holocene. Most of the species here listed are currently living in the Atlantic Coast of the Buenos Aires Province, except for T. farinatiae, I. anomala and the Subfamily Triphorinae, which do not reach the Argentine coast. The presence of T. farinatiae, I. anomala, and the Subfamily Triphorinae, together with warm water species such as Calliostoma carcellesi (Clench and Aguayo, 1940), Heleobia australis (d'Orbigny, 1835) and Epitonium georgettinum (Kiener, 1838) in the Holocene deposits suggest warm paleotemperatures during the MIS 1 Interglacial in this region.

An inverse latitudinal biodiversity pattern in asellote isopods (Crustacea, Peracarida) from the Southwest Atlantic between 35° and 56°S

Fil: Doti, Brenda Lia. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biologia Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biologia Experimental y Aplicada; Argentina

Molecular identification, morphological characterization and new insights into the ecology of larval Pseudoterranova cattani in fishes from the Argentine coast with its differentiation from the Antarctic species, P. decipiens sp. E (Nematoda: Anisakidae)

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. Larvae of Pseudoterranova decipiens s.l. have been reported in several fish species from off the Argentine coasts; however, there are no studies dealing with their specific identification in this region. Here, a genetic identification and morphological characterization of larval Pseudoterranova spp. from three fish species sampled from Argentine waters and from Notothenia coriiceps from Antarctic waters was carried out. Larvae were sequenced for their genetic/molecular identification, including the mitochondrial cytochrome c oxidase subunit II (mtDNA cox2), the first (ITS-1) and the second (ITS-2) internal transcribed spacers of the nuclear ribosomal DNA, and compared with all species of the P. decipiens (sensu lato) species complex (sequences available in GenBank). Further, adults of Pseudoterranova spp. from the definitive host, the southern sea lion, Otaria flavescens, from Argentine and Chilean coasts were sequenced at the same genes. The sequences obtained at the ITS-1 and ITS-2 genes from all the larvae examined from fish of Argentine waters, as well as the adult worms, matched 100% the sequences for the species P. cattani. The sequences obtained at mtDNA cox2 gene for Antarctic larvae matched 99% those available in GenBank for the sibling P. decipiens sp. E. Both MP and BI phylogenetic trees strongly supported P. cattani and P. decipiens sp. E as two distinct phylogenetic lineages and depicted the species P. decipiens sp. E as sister taxon to the remaining taxa of the P. decipiens complex. Larval morphometry was similar between specimens of P. cattani from Argentina, but significantly different from those of P. decipiens sp. E, indicating that larval forms can be distinguished based on their morphology. Pseudoterranova cattani is common and abundant in a variety of fish species from Chile, whereas few host species harbour these larvae in Argentina where they show low levels of parasitism. This pattern could arise from a combination of factors, including environmental conditions, density and dietary preferences of definitive hosts and life-cycle pathways of the parasite. Finally, this study revealed that the life-cycle of P. cattani involves mainly demersal and benthic organisms, with a marked preference by large-sized benthophagous fish.