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Garaffo G.V.,University of the Sea | Dans S.L.,CONICET | Dans S.L.,Brown University | Pedraza S.N.,CONICET | And 8 more authors.
Marine Ecology Progress Series | Year: 2011

Several species of small cetaceans inhabit the coastal area of Patagonia (Argentina), but little is known about their distribution and the degree of overlap between them. The goal of the present study was to build habitat-selection models for small cetaceans in order to assess areas of particular importance for the different species. These models were constructed using physiographic and remotely sensed variables. From 1994 to 2007, 13 aerial surveys were conducted along the Patagonian coast (from Golfo San Matías: 40° 40'-42°14' S, 65° 00'-63°47' W to Bahía de los Nodales: 48°00' S, 65°35' W). A grid of 0.5° × 0.5° cells was constructed for the study area. Each cell was characterized by environmental variables and by the encounter rate (ER) for each cetacean species. The ER of each species was investigated in relation to environmental variables using generalized linear models, and model averaging (multimodel inference) was used to obtain a predicted ER for the different species. The correlation between the ER of different species was analyzed by Spearman rank correlation. The environmental variables that were found to be significant predictors of species distribution differed between species. The ERs of dusky dolphin Lagenorhynchus obscurus and Peale's dolphin L. australis showed a positive relationship. Commerson's dolphin Cephalorhynchus commersonii presented a more coastal distribution than the other species, and individuals were more often found feeding in estuarine zones. Knowledge of the patterns of distribution of small cetaceans along the Patagonian coast provides baseline knowledge of how these species interact with each other and their environment. Such information should be considered when managing potential areas of conflict between coastal small cetaceans and human activities. © Inter-Research 2011.


Bayer M.S.,CONICET | Bayer M.S.,National University of Cordoba | Morsan E.,Institute Biologia Marina y Pesquera Almirante Storni | Gordillo S.,CONICET | And 2 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2015

Amiantis purpurata shells from the San Matías Gulf (SMG) were analysed in order to compare both morphology and size throughout the late Quaternary in relation to environmental changes. Shells from modern beaches, Holocene marine assemblages (late Holocene, 3630 ± 100 years bp) and interglacial Pleistocene marine assemblages (MIS 5, 100 ka years bp) were studied by measuring the height and length, and using the elliptic Fourier analysis (EFA) to take an outline contour. The Pleistocene shells were smaller, more elliptical and with a deeper lunule than the Holocene and modern ones. No significant differences were recorded in the allometry index throughout the late Quaternary. The variation in size and shape of the A. purpurata shells could be related to the phenotypic plasticity of this species as a response to the environmental changes registered in the SMG during the Quaternary. These changes include variations in sea surface temperatures, salinities and substrates, and also water circulation changes, which would have modified nutrient availability. Morphological changes imply burrowing activity, mechanical stability, nutrient uptake and defence response to predation. Copyright © Marine Biological Association of the United Kingdom 2015


Storero L.P.,CONICET | Storero L.P.,Institute Biologia Marina y Pesquera Almirante Storni | Ocampo-Reinaldo M.,CONICET | Ocampo-Reinaldo M.,Institute Biologia Marina y Pesquera Almirante Storni | And 3 more authors.
Marine Biology | Year: 2010

Phenotypic plasticity in response to environmental variability is one of the main characteristics of cephalopods. This study compares growth and life span of Octopus tehuelchus in different coastal environments of San Matías Gulf (Patagonia) at three different periods. The progression of maturity jointly with modal progression analysis and the detection of hatchlings in the natural environment were used to differentiate cohorts and assign ages. Growth was described using the oscillatory von Bertalanffy growth model. Within San Antonio Bay, O. tehuelchus seems to have the most favourable conditions for an extended spawning season and the development of two sub-annual cohorts. O. tehuelchus growth is strongly seasonal with slow growth rates during winter. There were differences in the growth pattern between sites and particularly between sub-annual cohorts in San Antonio Bay. The growth pattern in each site seems to be similar along the last 26 years. The results of our study make evident the variability and plasticity of O. tehuelchus in response to the environment. © Springer-Verlag 2009.


Molina L.M.,National University of Rio Negro | Molina L.M.,CONICET | Pereyra P.J.,Institute Biologia Marina y Pesquera Almirante Storni | Pereyra P.J.,CONICET | And 2 more authors.
Russian Journal of Biological Invasions | Year: 2015

The invasive Asiatic clam, Corbicula fluminea (Müller, 1778), is reported in new localities from the Negro River, from Conesa until Viedma. Fourteen years since its first record in this area, the species has established in the entire Negro River basin, upstream until Cipolletti and downstream until Viedma, where it reached densities up to 525 ind./m2. The most probable dispersal vector of clams is passive upstream and downstream transport which is probably facilitated by some human activities, such as fishing, fish stocking, recreational activities, sand and gravel extraction. This work state the southernmost record worldwide of C. fluminea. © 2015, Pleiades Publishing, Ltd.


Daleo P.,CONICET | Alberti J.,CONICET | Avaca M.S.,CONICET | Avaca M.S.,Institute Biologia Marina y Pesquera Almirante Storni | And 4 more authors.
Marine Biology | Year: 2012

Feeding decisions under predation risk can be a key in the life of scavenger organisms, and tuned recognition of predation alarm cues and flexibility in the response are fundamental. The effect of injured conspecifics on the response behavior of the whelk Buccinanops globulosum to feeding opportunities was experimentally evaluated in a Patagonian Bay (40°45′S, 64°56′W, Argentina) in September 2010. The effect of sex, size, body condition, or starvation on anti-predatory behavior was assessed. The number of B. globulosum feeding on carrion was reduced by half when damaged conspecifics were present. Smaller, lighter, and starved individuals responded less to the presence of damaged conspecifics. These results indicate that, under natural conditions, feeding avoidance after detecting damaged conspecifics is a common and important anti-predatory strategy of B. globulosum and show that morphology and starvation are significant factors in the context of the trade-off between feeding and avoiding predation risk. © 2012 Springer-Verlag.


Firstater F.N.,CONICET | Firstater F.N.,Institute Biologia Marina y Pesquera Almirante Storni | Hidalgo F.J.,CONICET | Lomovasky B.J.,CONICET | Iribarne O.O.,CONICET
Journal of Experimental Marine Biology and Ecology | Year: 2012

Bottom-up and top-down forces simultaneously influence benthic communities. However, their relative strength may vary with environmental conditions. In the Peruvian coast, the periwinkles are conspicuous grazers able to control both biofilm abundance and barnacle recruitment. Moreover, even in upwelling areas, algae living in the high intertidal may be nutrient-limited. Here we tested, in a nutrient-rich system, the relative effects of grazing and nutrient on the early succession of the high rocky intertidal. For this, we experimentally manipulated grazing and nutrient combined in a completely crossed design. Since nutrient and grazing seem to alter benthic community at different temporal scales, their effects were tested over the long-term (14. months) and the short-term (1. months). Over the long-term, barnacle cover increased throughout time, but was neither affected by grazing nor fertilization. At all sampling times fertilization increased biofilm cover and reduced bare rock, while exclusion of grazers also enhanced biofilm. The effect of grazing on bare rock varied through the succession. Macroalgae reached a maximum cover of 6.88%. Over the short-term, chlorophyll-a content was not affected by nutrient addition but was always higher in plots where grazer were excluded. Our results suggest that biofilm might be nutrient-limited in the high intertidal, despite being located in an upwelling area. However, the effects of grazers and nutrients on the biofilm are not reflected in macroalgae or barnacles, probably because of the occurrence of other structuring factors. In the short-term, grazing seems to have greater effect on biofilm, irrespective of the nutrient level, whereas over the longer-term, biofilm can take advantage of nutrient enhancement only in the absence of grazers. © 2012 Elsevier B.V..


Luzzatto D.C.,Institute Biologia Marina y Pesquera Almirante Storni | Luzzatto D.C.,CONICET | Sieira R.,CONICET | Pujol M.G.,Museo Municipal de Ciencias Naturales Lorenzo Scaglia | De Diaz Astarloa J.M.,CONICET
Cybium | Year: 2012

This study aimed at sequencing the mitochondrial cytochrome b gene (cyt b) of seahorses morphologically identified as Hippocampuspatagonicus Piacentino & Luzzatto, 2004 from the two known localities where the species occur in the Argentine Sea (San Antonio Oeste and Mar del Plata). Based on the lack of substitutions within cyt b found between the individuals of both localities, the geographical range of H. patagonicus was extended up to the Northern limit of the Argentine Sea. A phylogenetic analysis comparing the cyt b sequences of Hippocampus species revealed that H. patagonicus together with H. hippocampus and H. erectus belong to a monophyletic group of species. The comparison of the cyt b sequence of Hippocampus cf. erectus from Southern Brazil with that one of H- patagonicus resulted in scarce differences. This could suggest the presence of H, patagonicus in southern Brazil, although further investigation is needed to resolve the taxonomie status of H, erectus in the South Western Atlantic.


Storero L.P.,CONICET | Storero L.P.,Institute Biologia Marina y Pesquera Almirante Storni | Narvarte M.A.,CONICET | Narvarte M.A.,Institute Biologia Marina y Pesquera Almirante Storni | Gonzalez R.A.,Institute Biologia Marina y Pesquera Almirante Storni
Helgoland Marine Research | Year: 2012

This study evaluated the reproductive features of Octopus tehuelchus in three coastal environments of San Matías Gulf (Patagonia). Monthly samples of O. tehuelchus were used to estimate size at maturity, compare seasonal changes in oocyte size frequency distributions between sites as well as oocyte number and size between female maturity stage and sites. Females in Islote Lobos had a smaller size at maturity than females in San Antonio Bay and El Fuerte, probably as a consequence of a generally smaller body size. Males in San Antonio Bay were smaller at maturity than females. O. tehuelchus is a simultaneous terminal spawner. Fecundity (expressed as number of vitellogenic oocytes in ovary) was lower in Islote Lobos, and an increase in oocyte number in relation to female total weight was found. Females in San Antonio Bay had the largest oocytes, which may indicate higher energy reserves for the embryo and therefore higher juvenile survival. There was a close relationship between reproduction, growth and condition, represented as size at maturity, number and size of vitellogenic oocytes and period of maturity and spawning. Given the local variation in some reproductive features of O. tehuelchus, studies should focus on the environmental factors, which bring about this variation, and on how it affects the dynamics of local populations. © 2012 Springer-Verlag and AWI.


Galindez E.J.,National University of San Juan | Diaz-Andrade M.C.,National University of San Juan | Avaca M.S.,Institute Biologia Marina y Pesquera Almirante Storni | Estecondo S.,National University of San Juan
Brazilian Journal of Biology | Year: 2010

The oviductal gland is an exclusive structure of cartilaginous fishes that produces the egg jelly, forms the tertiary egg envelopes and stores sperm. The biological importance of this structure is related to the special features of the reproductive strategy of the group and to its phylogeny, considering that egg-laying is the ancestral condition in this fish (Dulvy and Reynolds, 1997). This gland of the smallnose fanskate shows four morphofunctional zones. The lining epithelium along the gland is columnar with secretory and ciliated cells. Secretions are mucous and/or proteic according to the zone, and to their specific functions. This is the first report about the microanatomy of the female reproductive tract of S. bonapartii with evidence of sperm storage in the genus.


PubMed | Institute Biologia Marina y Pesquera Almirante Storni
Type: | Journal: Marine environmental research | Year: 2011

Mussels in the San Matas Gulf fishery are targeted using artisanal dredges and diving. The main objective of this study was to assess the direct impact of artisanal dredging on the biota and sediments, and to compare the composition of the catches and the individual damage induced by fishing between dredging and commercial diving. The experimental design included samplings from dredge catches, dredge tracks, control sites and commercial diving. According to their damage level, individuals were scored as undamaged, lightly damaged and severely damaged. Sediment characteristics were analyzed using coring samples and traps. Damage of mussels, mostly corresponding to the severely damaged category, was less than 5% both in samples from dredging and diving. Conversely, mean damage of the main bycatch species (sea urchins and ophiuroids) was 75 and 65% in samples from dredging and diving respectively, being most of the individuals lightly damaged. Considering also the catch sample composition of both fishing methods, dredging affected relatively more individuals than diving. Although sediment removal in dredged areas was three times higher than that in non-dredged ones, mean grain size and gravel percentage of sea floor sediments showed subtle differences between them.

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