Age and Growth of Octopus Essay

372 WordsSep 15, 20122 Pages
Age and Growth of Octopus In order to determine the age of the octopus, scientist performed an experiment that would estimate the growth and the instantaneous rate of mortality, natural mortality, fishing mortality, and relative per recruit. The scientist in this experiment believed that there would be a difference in the age and growth of octopus over a length of time. 2675 samples were collected during the months of October 2000 to December 2002, from the Mandpam region, on the southeast coast of India. In order to determine the age, each sample ranged between 34 and 36 cm in length. The mantle length was taken as the standard measurement for determining age and growth of Octopuses. Data on Dorsal Mantle Length (DML) of O.aegina were grouped into 5mm class intervals and their frequencies in various classes were worked out. Growth was modeled following Von Bertalanffy’s Growth Function (VBGF). The total instantaneous mortality coefficient was estimated from the length frequency based catch curve method. The instantaneous natural mortality coefficient was found out by the following method Pauly and relative yield per recruitment Y/R was estimated by Beverton and Holt. Scientists performed a growth and mortality experiment as well using FISAT software. Growth was also modeled by following Von Bertalanffys Growth Function (VBGF). Experimental Variable and Control Variable The experimental variables in the study were all the different charts that they used to show the differences in age and growth overtime. The control variable was Von Bertalanffys Growth Function, because they measured all the data with the formula. The results on the study showed that the current rate of exploitation is well below the maximum sustainable yield and more units can be operated in this water for octopus fishing. This study has critical implications for gaining an accurate

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