FISHERIES POTENTIAL AND POSSIBLE MIGRATORY CIRCUITS FOR THE POPULATION ENHANCEMENT OF ASIAN Anguillid EELS IN PERENNIAL RESERVOIRS OF ANURADHAPURA DISTRICT IN SRI LANKA
The present study was evaluated the fisheries potential, ecological aspects, and possible
migratory circuits of two Anguillid eel species (Anguilla bicolor bicolor McClelland, 1844
and Anguilla bengalensis bengalensis Gray, 1831) in eight perennial reservoirs associated
with five river basins of Anuradhapura District, Sri Lanka. The study was conducted from
2019 to 2024, focusing on reservoirs such as Kalawewa, Rajanganaya, Nachcaduwa,
Nuwarawewa, Mahakanadarawa, Mahavilachchiya, Huruluwewa, and Padaviya, which are
connected to the Kala Oya, Malwathu Oya, Modaragam Aru, Yan Oya, and Ma Oya River
basins. Scientific data were compared with fishers’ Local Ecological Knowledge (LEK) on
eels, gathered through interviews with 59 eel fishers from May 2019 to July 2020. The
identification of two species of eels was confirmed using 16S rRNA gene sequencing (n=05
from each species). The fin differences index (FDI) further confirmed A. bicolor bicolor (FDI
5%) as short-fin and long-fin eels, respectively.
Four stages, glass eel, elver, yellow eel and silver eel were reported. Using yellow eels and
silver eels of A. bicolor bicolor (n=26) and A. bengalensis bengalensis (n=83), 24
morphometric measurements were reported, from which 17 morphometric characters were
found to be significantly different (p 6.5), higher mean total length (727.13 ± 101.93 mm and
803.80 ± 112.81 mm respectively), higher body weight (863.49 ± 334.37 g and 1178.74 ±
557.65 g respectively) and higher pectoral fin index (4.51 ± 1.36 and 5.17 ± 0.73
respectively). Histological studies of silver eels showed oocytes at the early and late
endogenous vitellogenic stages. Eel catch data showed an increase in numbers and weights of
eels from November to February. Phylogenetic analysis shows that the Sri Lankan species
indicates the possibility of a shared common ancestry with the Southeast Asian population.
LEK of fishers confirmed their possession of sound knowledge on the ecological and
biological aspects of eels. Results indicate a significant potential for an Anguillid eel fishery in
the Anuradhapura District and identify four migratory circuits related to Malwathu Oya,
Modaragam Aru, Kala Oya, and Ma Oya River basins.
Keywords: Anguilla bicolor bicolor, Anguilla bengalensis bengalensis, Catadromous
migration, Glass eel, Local Ecological Knowledge, Phylogenetic relationships, Silver eel
