The vertical distribution of shorefish — primarily reef fish — larvae in the upper 20 m in relatively shallow (<30 m)="" waters="" of="" the="" great="" barrier="" reef="" lagoon="" near="" lizard="" island="" was="" investigated="" from="" 27="" february="" to="" 7="" march="" 1983="" during="" both="" day="" and="" night.="" four="" strata="" were="" sampled="" by="" neuston="" net="" and="" opening/closing="" bongo="" net:="" neuston="" (0="" to="" 0.1="" m),="" upper="" (0="" to="" 6="" m),="" middle="" (6="" to="" 13="" m),="" and="" deep="" (13="" to="" 20="" m).="" taxon-specific="" patterns="" of="" vertical="" distribution="" which="" changed="" little="" ontogenetically,="" were="" found="" for="" the="" 50="" taxa="" (in="" 24="" families)="" analysed.="" vertical="" distribution="" was="" highly="" structured="" during="" the="" day,="" and="" with="" few="" exceptions="" was="" nearly="" unstructured="" at="" night.="" most="" taxa="" had="" highest="" concentrations="" deep="" in="" the="" water="" column="" during="" the="" day,="" but="" in="" any="" given="" stratum="" some="" taxa="" had="" highest="" concentrations.="" day/night="" changes="" in="" pattern="" apparently="" were="" due="" to="" randomization="" or="" spread,="" rather="" than="" active="" migration.="" related="" taxa="" had="" similar="" patterns.="" similarity="" analysis="" including="" 211="" taxa="" produced="" three="" groupings="" of="" samples:="" day="" neuston;="" day="" upper/middle;="" and="" day="" deep="" plus="" all="" night="" samples.="" the="" sampling="" strategy="" of="" using="" drogues="" to="" tag="" water="" parcels="" for="" subsequent="" resampling="" was="" compared="" with="" one="" of="" sampling="" at="" a="" fixed="" point.="" the="" drogue="" strategy="" was="" not="" superior="" to="" the="" fixed-point="" strategy="" as="" measured="" by="" dissimilarity="" indices,="" but="" this="" may="" differ="" among="">