Forecasting and Comparison of Nonlinear Statistical Growth Models for Fish Seed Production in Eastern Coastal States of India
M. Rajani *
College of Fishery Science, Andhra Pradesh Fisheries University, Muthukur, Nellore, Andhra Pradesh (524 344), India.
A. Balasubramanian
College of Fishery Science, Andhra Pradesh Fisheries University, Muthukur, Nellore, Andhra Pradesh (524 344), India.
M. Hemanth Kumar
Department of Statistics, Hindu College, University of Delhi, India.
*Author to whom correspondence should be addressed.
Abstract
The study was carried out to compare the goodness of fit of three non–linear growth models viz., Monomolecular, Logistic and Gompertz growth models and analysing the instability index among the collected fish seed Production data from the eastern costal states of Indian for the period from 1994–1995 to 2019–2020. The parameters of each model were estimated using Levenberg–Marquardt (LM) iterative method. The ‘independence’ and ‘normality’ of error terms were examined by using ‘Run–test’ and ‘Shapiro–Wilk test’. Among the three models tested, monomolecular model was found as best model to describe variation in fish seed production in all Eastern Costal States of India. The values of CDI for fish seed production were 146.94 %, 79.30 % and 63.41% respectively which revealed that fish seed production had high instability in Odisha, Tamil Nadu and Andhra Pradesh while low instability (14.93 % and 13.13%) in West Bengal and India.
Keywords: Fish seed production, nonlinear models, levenberg-marquardt method, run-test, shapiro-wilk test, goodness of fit