EFFECTS OF ACIDIFICATION ON FISH LARVAL ABUNDANCE AT TEKNAF COAST, BANGLADESH

Abstract

The study aimed to investigate the effects of acidification on fish larvae abundance at the Teknaf coast. From January 8 to December 14, 2021, samples of fish larvae were collected at every month from the Teknaf coast. From the bottom to the surface, Bongo-Net with a 500 µm mesh size was being towed. A total of 1,120 larvae were gathered from the research area during the survey. In the study region, 93 larvae/1,000 m3 were found to be the mean density of all fish larvae. The hydrological parameters such as water temperature, pH, salinity, and total alkalinity were determined to find out the effects of these variables on the larvae abundance along the Teknaf coast. The average values of the parameters including water temperature, pH, salinity, and total alkalinity were found at 28.41°C, 8.36, 23.57 PSU, and 113.25 mg/l respectively. The ocean acidification factors including pCO2, HCO3-, CO32-, DIC, ΩAragonite, and ΩCalcite were also determined by using the "seacarb" package of R programming to find out the effects of these variables on the larvae abundance along the Teknaf coast. The average values of the factors including pCO2, HCO3-, CO32-, DIC, ΩAragonite, and ΩCalcite were found 128.72 µatm, 0.000751 mole/kg, 0.000138 mole/kg, 0.000892 mole/kg, 2.3544 and 3.7028 respectively. The results showed an insignificant relationship between pCO2 and fish larvae abundance throughout the Teknaf coast. However, there was a negative correlation between pCO2 and pH. The findings of this research indicate that OA affects fish larvae abundance at Teknaf coast. Regional fisheries management organizations will be better able to make decisions about the management of the extremely valuable fish larvae as a result of future population-level predictions of the impacts of ocean acidification.