Altomari L.N., Barros M.R.F., Santos W.C.R., Herrmann M., Chagas R.A.
*contatolaltomari@gmail.com
The present study aims to analyze the effects of El Niño on the growth of the oyster Crassostrea tulipa on the Amazon coast through the Overall Growth Performance (OGP) index. This index compares the general growth functions of von Bertalanffy from several studies, analyzing the growth parameters (K and L∞) of the species and ordering the data in an auximetric grid. In this experiment, the labeling method using fluorochrome calcein was used. The experiment started in April 2016 (during El Niño 2015/16) and continued for a period of one year. All experimental conditions were based on a previous study carried out (in 2013 – normal year). At each collection, 30 oysters were sampled. In the laboratory, after washing and drying, the shells of the oysters were embedded in crystal resin and cut longitudinally using a diamond saw. After polishing the resulting cuts with different grades of carbide powder and aluminum oxide, the absolute growth rate was determined by detecting calcein marks with a fluorescence microscope. The results of this study indicate a significant difference in the growth parameters of oysters under the influence of El Niño. This influence occurs in a different way, correlated with the strength of the climatic anomaly. In conclusion, there was a negative influence of El Niño on the growth of oysters C. tulipa, grown on the Amazon coast, when compared to growth in normal years. It is estimated that oysters grown in El Niño year take approximately three more months to reach their commercial size.
Keywords: Bivalve mollusk, oyster farming, growth parameters, El Niño.