GOPALAKRISHNAN: ZOOGEOGRAPHY OF NEMATOSCELIS 



120" 



-=r= 



130" 



APRIL 16 - OCTOBER 15 

 (DAY STATIONS) 



No. of INDIVIDUALS per co 200m' 



Nematoscelis atlantica 



• 1-24 



• 25-74 



MO" ISO- 



20» 50" 40" 5<r 60* TO" •O' W (OCT IIC 120* 130* t4(r ISO* 



Figure 9. — Locality records and daytime abundance of larvae and juveniles of Nematoscelis atlantica in the Indian Ocean: b - SW 



Monsoon period. 



Geographical Distribution of 



N. microps 



Indian Ocean 



Nematoscelis microps has wider ranges of dis- 

 tribution than N. gracilis and N. atlantica. This 

 species penetrates the Arabian Sea and the Bay of 

 Bengal only at their western and eastern sides 

 respectively (Figure 12a, b). The northernmost 

 record of this species in the western Arabian Sea 

 was at lat. 14°N and that in the eastern side of the 

 Bay of Bengal at lat. 19°N off the coast of Burma. It 

 does not live in the poorly oxygenated subsurface 

 waters of the Arabian Sea and Bay of Bengal. In 

 midocean the northern boundary does not extend 

 north of lat. 6°N and the southern boundary not 

 beyond lat. 30°S. It was caught less frequently 



from the southern central gyre south of lat. 10°S. 

 Nematoscelis microps is a predominant species of 

 the South Equatorial Current and the West Aus- 

 tralian area. The Agulhas Current apparently 

 brings it around the tip of South Africa. 



There was not much seasonal change in the 

 distribution of this species in the Indian Ocean. 

 Larvae and juveniles were present in the Somali 

 Current area during both monsoon seasons but 

 were carried as far north as lat. 14°N only during 

 the SW monsoon. They were present throughout 

 the year in the Andaman Sea area. During the NE 

 monsoon adults were not caught in the Somali 

 Current area north of the Equator, whereas they 

 were present as far north as lat. 12°N during the 

 opposite season when the flow is northeastward 

 (Figure 13a, b). Adults occurred in the North 

 Equatorial Current area during the NE monsoon 



1057 



