ROTHLISBERG: VERTICAL MIGRATION OF PENAEID SHRIMP LARVAE 



Surface 



Scale a.b.c 



Figure 7.— Progressive vector diagrams for horizontal 

 advection, based on 2-h median larval distributions and 

 currents at Station 210, north of Groote Eylandt on 22- 

 23 March 1977. a) Advection over 24 h of a larva spend- 

 ing 12 h of daylight at the bottom stratum and 12 h of 

 night at the surface (dotted line), a nonmigratory ani- 

 mal at the surface (solid line), and a nonmigratory 

 animal near the bottom (dashed line); b)zoeal substages 

 1-3 (solid, dashed, dotted lines, respectively); c) mysis 

 substages 1-3 and postlarvae (solid, dashed, dotted, dot- 

 dashed lines, respectively); d) 14-d extrapolation of 

 daily resultant vectors: nonmigratory surface (dashed 

 line); nonmigratory bottom (dashed line); 12:12 surface 

 bottom larva (dotted line); median larva (solid line). 



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