172 Karunarathne et al. 39(2) Jellyfsh Species Used as Live Baits in Traditional Trap Fishery of Sri Lanka: Acromitus fagellatus and Lychnorhiza malayensis (Cnidaria: Scyphozoa) KRISHAN D. KARUNARATHNE and M. D. S. T. DE CROOS* Department of Aquaculture and Fisheries, Faculty of Livestock, Fisheries and Nutrition, Wayamba University of Sri Lanka, Makandura, Gonawila (NWP) - 60170, Sri Lanka Received: 01.03.2021 Accepted: 08.06.2021 Two species of scyphozoan jellyfsh were observed to be used as live baits in a traditional small-scale trap fshery operated in the eastern Sri Lanka. However, there was limited taxonomic knowledge on the respective scyphomedusae. Therefore, altogether 83 specimens of these jellyfshes netted from several coastal localities of the country from 2016 to 2020 and eight museum specimens were examined taxonomically to reveal their identity. Of the species identifed, Acromitus fagellatus was reported for the frst time from Sri Lanka while Lychnorhiza malayensis was re-reported and these two species are presented here with detailed descriptions. As both species are mild stingers, so far no severe health issues have been reported in Sri Lanka. However, as bloom-forming species clogged jellyfsh have adversely affected gillnet, trammel-net, and stake-net operations in coastal water bodies of Sri Lanka by reducing fsh catches and damaging nets. (Key words: Artisanal fsheries, First records, Medusae, Morphology, Taxonomy) *Corresponding author: E-mail: dileepa_dc@yahoo.com/dileepad@wyb.ac.lk J. Indian Soc. Coastal Agric. Res. 39(2): 172-182 (2021) https://doi.org/10.54894/JISCAR.39.2.2021.110892 Scyphozoan jellyfsh are generally known to affect the fshing industry, tourism, aquaculture and machinery (Purcell et al., 2007; Richardson et al., 2009). Some jellyfsh can also have ecosystem impacts such as indirect effects on fsheries resources via predation of ichthyoplankton, being vectors for parasites and becoming invasive species (Purcell et al., 2007; Richardson et al., 2009). Despite this, jellyfsh are important in stabilizing the marine ecosystem by supporting nutrient cycling (Lebrato et al., 2012), and establishing symbiotic relationships with fshes (Purcell and Arai, 2001). Moreover, several species of jellyfsh are exceptionally benefcial for various industries. For example, some species are harvested for direct human consumption (Omori and Nakano, 2001; Kitamura and Omori, 2010) while, some other species are used in aquaria and zoos (Aquatic Invertebrate TAG, 2013). Moreover, products derived from jellyfsh are used in livestock, agriculture, aquaculture, cosmetic industry and pharmaceutical industry (Brotzand Pauly, 2017). Some jellyfsh species are also used as bioindicators for environmental monitoring (Templeman and Kingsford, 2000), material science (CIESM, 2011), and fshing (Table 1). They are important as a feed for newly hatched phyllosomas in sand lobster aquaculture as well (CMFRI, 2015). In Sri Lanka, jellyfshes are not consumed thus, most of the species have no commercial value. But processed bells and oral arms of a Crambionella species and Lobonemoides species, which are respectively from the southeastern and northwestern coasts of the country, are exported in some quantities (Authors’ unpublished data). Also, Cassiopea andromeda (Forskål, 1775) reported from northern Sri Lanka is used as an ornamental species in some public aquaria of Sri Lanka (Karunarathne et al., 2020). Altogether fve rhizostome jellyfsh species of Scyphozoa were reported with morphological descriptions by Stiasny (1931), Karunarathne and de Croos (2020), and Karunarathne et al. (2020) while, Fernando (2006) had reported Lychnorhiza malayensis Stiasny, 1920 from Sri Lanka but neither any description nor photographs were provided. Maran et al. (2021) provided only short descriptions of L. malayensis and an unknown Acromitus species, which were reported from Sri Lanka. These two species were observed to be swarming in coastal waters of eastern Sri Lanka at the end of the northeast monsoon along with the increment of salinity level in brackishwater bodies and are used as live baits in traditional trap fsheries operated along the same coastline to capture demersal fsh species (Karunarathne et al., 2021). Both of the relevant jellyfsh species were taxonomically examined in this study and