Publications by authors named "E M Morsan"

The system formed by a still-unidentified rhizocephalan infecting the Patagonian stone crab Danielethus (Platyxanthus) patagonicus (A. Milne-Edwards, 1879) was analyzed in northern Patagonia. Out of 3222 crabs sampled, mean prevalence of externae was 2.

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Global losses of oyster populations urgently necessitate evaluating the status of underdocumented populations. The north-Patagonian Ostrea puelchana metapopulation changed in recent decades: certain beds grew and expanded; others became depleted by the Bonamia exitiosa epizootic. We surveyed eight oyster beds from the San Matías and San José gulfs; assessing the extension, demographic structure, and density-distribution pattern of each.

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In the absence of instrumental records, shell growth increments of bivalves are used to build continuous multi-decadal time series of growth and to estimate environmental variability. While there is interest in such chronologies in the Northern Hemisphere, there is a lack of multi-decadal datasets of growth for marine species from the Southern Hemisphere. We assessed the potential of the clam Glycymeris longior as an environmental proxy archive for the mid-latitudes of the South Atlantic Ocean, by applying sclerochronological techniques on the shells of individuals from a coastal area in Northern Patagonia, Argentina.

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Wild oyster populations have declined severely worldwide, however fluctuations of South Atlantic populations are poorly documented. We explored the changes in the abundance of Ostrea puelchana population of Northern Patagonia, Argentina, by linking data from paleontological, archaeological and informal sources, with time series data from fishing, ecological and studies of oyster pathology. The present work is the first study which includes a South Atlantic time series concerning oyster beds.

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Between 1995 and 1996, Bonamia exitiosa caused an epizootic in San Matías Gulf, Argentina, that spread from a commercial culture site of Ostrea puelchana to natural beds located at the northeastern coast of the gulf. A mortality rate of 95% was registered in cultured oysters, and oysters from natural beds were also affected. The aims of this study were to assess the parasite prevalence in oyster beds and the demographic structure 14 yr after the epizootic.

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