Reproductive Biology of Splendid Ponyfish Leiognathus Splendens(Cuvier,1829)in Myeik Coastal Waters,Myanmar

Reproductive biology of Leiognathus splendens was studied by using the samples collected from the catches of trawl fisheries in Myeik coastal waters during January to December 2014.Spawning takes place throughout the year,with a peak during April-May and September-December.The observed length at first maturity was 9.0 cm total length in males and 8.4 cm in females.The mean gonadosomatic index was more prominently in females(2.5)than males(1.5).Sex ratio(1 male:1.1 females)also indicates the general dominant of females over males Fecundity varied from 6120 to 58412 eggs.Relationship of fecundity to fish length,fish weight and ovary weight showed that fecundity is more related to the gonad weight(r=0.9)than length(r=0.8)and weight of fish(r=0.7).

Three-Dimensional Climatological Structures of the Arabian Sea Eddies and Eddy-Induced Flux

This study explores the spatial structure and transport characteristics of eddies in the Arabian Sea(AS)using Argo profiles and satellite measurements.The majority of eddies occur in the northern AS,especially along its northeastern boundary.In contrast,the western AS had a relatively higher eddy kinetic energy compared to the eastern part.Particularly,the strongest energetic eddies were present in the Somali Current system.The composite results revealed the evident thermohaline anomalies caused by cyclonic eddies(CEs)and anticyclonic eddies(AEs)in the upper 300m layers.The anomalous temperature structure within CEs and AEs showed a dominant dipole structure in the near-surface layer and a monopole structure below,with maximum temperature anomalies of approximately−0.8℃and+1.0℃located at depths of 100–150m,respectively.The composited salinity structures for CEs and AEs exhibited monopole vertical structures and sandwich-like patterns.For AEs,large positive salinity anomalies occurred at subsurface layers of 60–180 m with a peak value of about 0.07,and weak negative values were observed above 60m and below 180 m.A similar vertical structure but with an opposite sign operates for CEs.The composited CE and AE caused an equatorward salt flux with values of−8.1×10^(4)and−2.2×10^(4)kg s^(−1),respectively.CEs caused an equatorward heat flux of−7.7×10^(11)W,and AEs induced a poleward flux of 1.5×1011 W.

Fish Species Diversity in Upstream and Downstream of Sittaung River,Bago Region,Myanmar

This research was conducted to generate a primary database on ichthyofauna,distribution and diversities in the upstream and downstream segments of Sittaung River in Bago Region of Myanmar.This study contributes to the information needed on the distribution of river fish in Myanmar.Fish diversities are assessed by calculating the various diversities indices between December,2018 and November,2019.A total of 65 fish species belonging to 9 orders,23 families and 49 genera were recorded.All 65 fish species were found in upstream segment but only 60 species of them were found in downstream segment of the river.In all study sites,Shannon diversity index had value above 3 indicating that the structure of habitat was stable and balanced.Simpson’s index values were close to 1 in all sites indicating that the species richness in the region was satisfactory.The abundance all of above 5%of total catch of Mystus vittatus,M.pulcher,M.cavasius and Erethistes pusillus in their feeding habitat suggested that their upstream and downstream habitats provided suitable feeding conditions.Anguilla bengalensis,Tenualosa ilisha,Mystus gulio,Rita rita and Silonia silondia were least abundant all below 0.1%of total catch showing they could be impacted by unwise anthropogenic activities.Assessing fish species diversity is thus very important to conserve and manage and promote the health of river ecosystem that is necessary for the migration of fish species.

Diversity and Abundance of Copepods in Taninthayi Coastal Waters, Myanmar

Diversity and abundance of copepods occurring in Taninthayi coastal waters were studied and analyzed from the samples collected by R/V DR.FRIDTJOF NANSEN during the Myanmar ecosystem survey 2018.Seventy-nine copepods species belonging to calanoids(51 species),cyclopoids(21 species),and harpacticoids(7 species)were identified in the copepods community of Taninthayi coastal waters.Copepods species number and density were high at the nearshore stations(Sts 799,842,788)and low at the offshore stations(Sts 846,802,823).The resulted diversity index values of copepods were varied from 2.61 to 3.78 in species diversity index(H'),from 0.89 to 0.97 in the evenness index(E'),and from 2.51 to 7.50 in species richness index(D').According to the correlation matrix,the abundance of copepods was positively correlated with temperature,chlorophyll a and fluorescence,and negatively correlated with salinity and oxygen.