Esteban Avigliano

Heavy metals and trace elements in muscle of silverside (Odontesthes bonariensis) and water from different environments (Argentina): aquatic pollution and consumption effect approach

The concentrations of As, Ag, B, Ba, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hg, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Rb, Sb, Se, Sn, Sr, Te, Ti, U, V and Zn were determined in water and silverside (Odontesthes bonariensis) muscle samples from four important commercial fishing sites (Argentina) by ICPMS. Trace element concentrations in water with well-documented human health effects were above the recommended maximum levels established by Argentinean and international guidelines for the aquatic biota protection in three sampling sites (e.g. As: 28.4-367 μg L(-1); Cd: 0.17-1.05 μg L(-1); Hg: 0.07-0.63 μg L(-1); Zn: 71.3-90.0 μg L(-1)). High concentrations of As, Hg and Pb (0.03-0.76; 0.03-0.42 and 0.04-0.19 mg kg(-1) wet weight, respectively) were found in silverside muscle. Fishing communities associated with contaminated environments are likely to have higher consumption rates and are thus more likely to be exposed to higher concentrations of the toxic elements (As, Hg and Pb).

Use of otolith strontium:calcium ratio as an indicator of seasonal displacements of the silverside (Odontesthes bonariensis) in a freshwater) marine environment

Strontium:calcium (Sr:Ca) ratios were measured in sagittal otoliths of silverside (Odontesthes bonariensis) from a freshwater-marine environment (ParanaRiver Delta and Ro´o de la Plata River, South America) in order to understand its seasonal movements. Conductivity was recorded and the water Sr:Ca ratio was determined by inductively coupled plasma-atomic emission spectrometry (ICP-OES). A calibration curve of water Sr:Ca ratio versus otolith Sr:Ca ratio from four isolated lentic water bodies was made to predict silverside displacements in the lower section of the Plata Basin during summer (lotic water bodies). Otolith Sr:Ca ratio of silversides from the ParanaRiver Delta was associated with the conductivity of water at the locations where the sample was collected. According to this association and the obtained results in the calibration curve, the silversides were displaced from zones where conductivity was 7.45 (mScm � 1 ), corresponding to the water Sr:Ca ratio in the outer section of the Ro´o de la Plata River (1.92mmolmol � 1 ). The high values of otolith Sr:Ca ratio found for some fish may indicate that during summer they moved from estuarine waters where salinity increases gradually to the Argentinian Sea. Additional keywords: estuarine, Odontesthes bonariensis.

Use of lapillus otolith microchemistry as an indicator of the habitat of Genidens barbus from different estuarine environments in the southwestern Atlantic Ocean

The marine catfish Genidens barbus is an anadromous species from South America. The aim of the present study was to evaluate the use of lapillus otolith microchemistry (Sr:Ca; Ba:Ca and Mg:Ca ratios) as an indicator of changes in habitat use and identify the potential breeding areas and fish stocks of G. barbus populations from the Plata Basin (Paraná River Delta and De la Plata River estuary-Argentina) and Lagoa dos Patos coastal lagoon (southern Brazil). Sr:Ca, Ba:Ca and Mg:Ca ratios were measured in the core area (inner 4 rings) and external area (outer 3–4 rings) of the otoliths by ICP-OES. The Sr:Ca ratio tended to be higher in the otolith external area than in the core area, while the Ba:Ca ratio followed the opposite pattern. This suggests the displacement of fish toward higher salinity areas. The Sr:Ca, Ba:Ca, Mg:Ca ratios in the core and external areas of the otoliths from the Plata Basin differed significantly from those of the otoliths from Lagoa dos Patos. This may indicate the occurrence of two different breeding sites and at least two fish stocks in the study region.

A Review of the Application of Otolith Microchemistry Toward the Study of Latin American Fishes

ABSTRACT In developed countries, otolith microchemistry has been used for more than three decades for studies of life history, migration, and environmental ecology of fish stock of commercial importance. Although Latin America produces 16% of the annual fish capture, most of their fishery resources have not been well studied and handled. Modern methodologies related to microchemistry have not been applied to the underdeveloped countries of Latin America due to its high cost. In the last decade, there have been several studies on Latin American resources, carried out mainly by first world countries. Currently, some regional economies are strong and stable enough to ensure the training of specialized human resources and to generate opportunities for the exchange of projects and acquisition of state-of-the-art technology. In this work, all available literature associated to Latin American resources in relation to the use of otolith microchemistry has been reviewed. The use of different methodologies in the region in relation to global trends has been discussed. In addition to that, the extent of collaboration between underdeveloped and developed countries has been evaluated. This review shows a promising future in the application of otolith microchemistry to study biology of fishes, which will impact on the medium and long term to ensure the sustainability of certain resources and, therefore, the strengthening of regional economies.

Assessment of the morphometry of saccular otoliths as a tool to identify triplefin species (Tripterygiidae)

In the present work we describe nine saccular otolith morphometric indices (circularity, rectangularity, aspect ratio, percentage of the otolith surface occupied by the sulcus, percentage of the sulcus length occupied by the cauda length and ostium length, otolith length relative to the length of the fish, rostrum aspect ratio and percentage of the rostrum length occupied by the otolith length) of 41 species of the Tripterygiidae family collected mainly from New Zealand, Australia, Chile, South Africa, Mediterranean Sea and North America. The principal component of analysis showed that the indices that best explain the variability between species were related to sulcus and rostrum morphometry. According to cluster analysis, otolith morphometry could reflect the diversity of microenvironments for some genera such as Notoclinops and Forsterygion , while this does not happen to genera like Enneapterygius and Ruanoho . The discriminant analysis showed that the species Helcogrammoides cunninghami, Karalepis stewarti, Lepidoblennius haplodactylus, Notoclinus compressus, Ucla xenogrammus can be discriminated by using the morphometric indices. Two new indices related to the sulcus that were of great value for the discrimination of these species are described for the first time. This information will be a useful tool for palaeontological, taxonomic and trophic ecology studies.

Use of otolith strontium:calcium and zinc:calcium ratios as an indicator of the habitat of Percophis brasiliensis Quoy & Gaimard, 1825 in the southwestern Atlantic Ocean

Fish were collected in three sampling sites: Argentine-Uruguayan Common Fishing Zone (AUCFZ), El Rincon (ER) and San Matias Gulf (SMG). The otolith Sr:Ca and Zn:Ca ratios were determined by ICP-OES and EDTA volumetric method. The otolith Sr:Ca ratio was similar in the three sampling sites, while the Zn:Ca ratio was significantly higher in AUCFZ than in ER and SMG for all age groups. The discriminant analysis showed an association between the otolith Sr:Ca and Zn:Ca ratios from ER and SMG. Present results suggest the potential occurrence of two fish stocks of

Nursery areas and connectivity of the adults anadromous catfish (Genidens barbus) revealed by otolith-core microchemistry in the south-western Atlantic Ocean

The anadromous catfish, Genidens barbus, is a commercial and vulnerable species from South America. The aims of the present study were to assess whether the nursery areas can be discriminated by using microchemical signatures of lapillus otoliths, to assess the accuracy of classifying fish in relation to natal nursery area and to discuss the possibility of existence of homing behaviour. Thus, the otolith-core chemical signatures (barium (Ba):calcium (Ca), lithium (Li):Ca, magnesium (Mg):Ca, manganese (Mn):Ca, strontium (Sr):Ca, and zinc (Zn):Ca ratios) of adult fish were compared among different estuaries (De La Plata River in Argentina, and Patos Lagoon, Paranagua Bay and Guanabara Bay in Brazil). PERMANOVA analysis showed significant differences in the multi-element signatures of the otolith core among sampling sites for all cohorts (2002, 2003, 2006 and 2007), indicating that the technique has considerable potential for use in future assessments of population connectivity and nursery areas of G. barbus. Via quadratic discriminant function analysis, fish were classified to natal nursery areas with 80–100% cross-validation classification accuracies. These results suggested that a high level of spatial segregation exists in adult catfish life and homing behaviour could not be ruled out on the basis of our data.

Actinopterygii, Atheriniformes, Atherinopsidae, Odontesthes bonariensis Valenciennes, 1835: new records for the Plata Basin, Argentina

The present work reports the presence of the silverside Odontesthes bonariensis Valenciennes, 1835, in 11 water bodies and six new locations from the lower Plata Basin (Argentina).

Short spatial and temporal scale patterns of fish assemblages in a subtropical rainforest mountain stream

The fish fauna of a subtropical mountain stream in Argentina was surveyed for the first time. The abundance and occurrence of species were explored considering variation in hydrology, seasonality and the abiotic environment. We collected 221 individuals of 23 species from 10 families and four orders. Small sized species and small individuals dominated the fish fauna. The small characid Astyanax saguazu was the most conspicuous species. Hydrology, seasonal changes in water temperature and variation in water conductivity affected the abundance and distribution of fish. Hypobrycon maromba is recorded in Argentina for the first time.

Migration and brackish environment use of Prochilodus lineatus (Characiformes: Prochilodontidae) inferred by Sr:Ca ratio transects of otolith

otolith sections were analyzed for Sr:Ca with laser ablation-inductively coupled plasma-mass spectrometry (LA ICP-MS) to infer habitat use of fish. To the interpretation of transects, a threshold that represents the transition between freshwater and brackish environments was calculated using the Sr:Ca ratio of the otolith edge of specimens captured in the first section of the La Plata Estuary (salinity ≥ 0.5 PSU). The percentage of fish using the estuary was higher in the Parana (37%) than the Uruguay River (5%). Change-point analysis showed that fish entered the estuary between 1 and 3 times throughout life at a wide range of ages (0-15 years). These incursions had no obvious periodicity. This information should be integrated into future management actions, which should also be specific to each area since migration patterns differ between the major rivers of the basin.