Abstract:
In Sri Lanka, fish provide about 50% of the animal protein consumed, which is nearly three times
the global average. The country’s fisheries, including marine, inland and aquaculture sectors, play
an important role in food security and livelihoods. However, significant price fluctuations have
impacted stakeholders such as fishers, traders and consumers. This study analyses price trends
and seasonal patterns of selected six fish species (large pelagic and small pelagic) consumed by
Sri Lankans and available in Colombo market. Monthly retail prices from January 2014 to
December 2024, obtained from the Hector Kobbekaduwa Agrarian Research and Training
Institute, were used to develop a forecasting model for better market insights. The Augmented
Dickey-Fuller (ADF) test confirmed that the first order differenced real price series were
stationary. Accordingly, the Autoregressive Integrated Moving Average (ARIMA) and Seasonal
ARIMA (SARIMA) models were used for analysis with R software. Results show an upward trend
in nominal prices, mainly due to inflation while real prices remain stable over time. Seasonal price
index values indicate variations in the monthly average real prices of different fish species linked
to monsoon seasons. SARIMA models consistently provided the best fit for forecasting the prices
across allspecies. For Salaya, Hurulla, Balaya, Kelawalla, Thora and Talapath, the best-fitting
SARIMA models were (2,1,2)(0,1,12)[12],(1,1,2)(1,0,12)[12],(0,1,2)(2,0,12)[12],
(0,1,3)(0,0,12)[12],(0,1,5)(0,0,12)[12] and (0,1,2)(0,0,12)[12] respectively, with AICc values ranging
from 1295.76 to 1674.75, MAPEs between 0.0506 and 0.0885 and R-squared values from 0.7536
to 0.9149, indicating strong predictive accuracy across all species. The findings suggest that the
apparent increasing trend in nominal fish prices is influenced mainly by external factors such as
inflation, supply chain disruptions and weather patterns. These results highlight the need for
price stabilization and continuous market monitoring mechanism to enhance affordability and
improve the value chain in the sector.
