Morphological characteristics and distribution of Najas indica (Wild.) Cham. in Cau Hai lagoon, Thua Thien Hue province

Abstract

The paper reports the morphological characteristics and distribution of Najas indica in the Cau Hai lagoon from March 2018 to March 2019. N. indica has a fairly wide distribution area in the Cau Hai lagoon, from the center towards the western bank, and exists in 10/21 surveyed sites. The coverage and biomass of N. indica differ significantly in the surveyed months. The species starts to increase its coverage and biomass in April, and the highest value of coverage is recorded from July to November (49.33 ± 15.05%÷52.60 ± 12.28%), while the biomass peak occurs in July (93,61 ± 35,60 g/m²). The distribution of N. indica partly depends on air temperature and salinity. The results demonstrate that air temperature variation is strongly correlated with biomass; whereas, water salinity shows a relatively weak correlation with the species’ biomass and coverage.