Lyczkowski-Shultz and Steen: Diel vertical distribution of Sciaenops ocellstus in northcential Gulf of Mexico 



633 



CRUISE 84-9-1 



IO 



25 



o 20 

 o 



Q. 

 



c 



60-| 



I 5 II I 5 II I 5 II 



DEPTH (m) 

 1650-1854 2355-0152 0650-0844 



® © 



TIME (hr CST) 



I 5 12 I 5 12 I 5 12 



DEPTH (m) 

 1119-1409 I9II-2II8 0725-0927 



® © 



TIME (hr CST) 



CRUISE 84-10-1 



-OFFSHORE 



I 3 7 

 1056-1246 



5 12 I 5 16 



OEPTH (m) 

 1202-1445 1904-2101 0640-0831 

 ® © 



TIME (hr CST) 



NE4RSH0RE 

 n=2 



I 5 9 

 1308-1223 



35 



30 



"6 25 

 o 

 o 



cr 2° 



ill 



Q. 



uj 15- 



tr 

 < 10 



5 



CRUISE 85-9-1 



-OFFSHORE 



n = 3 



n = 3 

 + 



I 5 II 



«=i 



., 



. n=l 



I 5 12 I 5 12 I 5 II 



DEPTH (m) 

 1333-1526 1853-2047 0704-0851 



© ® 



TIME (hr CST) 



NEAR SHORE 

 n = l 



I 3 7 



5 II I 5 II 



DEPTH (m) 

 1244-1501 1931-2145 0742-1008 1359-1532 



© ® 



TIME (hr CST) 



CRUISE 85-10 



OFFSHORE 



Figure 2 



Mean and range in density of red drum larvae Sciaenops ocellatus by sampling depth and time at offshore and 

 nearshore sites during cruises in 1984 and 1985. n = number of collections per sampling period. Crosshatch- 

 ing denotes nighttime observations. Encircled H and L symbols mark the approximate times of high and low tide. 



Vertical profiles of temperature and salinity prior to 

 sample collection were obtained with the CTD. 



Ichthyoplankton samples were preserved at sea in 

 5-10% formalin and were later (1 week to 6 months) 

 transferred to 70% ethanol for final preservation. In 

 the laboratory, all larvae were removed from either the 

 entire sample or from a one-half aliquot which was ob- 



tained using a Motoda plankton splitter (Van Guelpen 

 et al. 1982). Standard length (SL) of larvae was mea- 

 sured to the nearest 0.1mm at 12 x using a stereo- 

 microscope. Larval densities are reported as number 

 per 100 m 3 . 



Zooplankton samples were collected by pumping 

 water up from the same depths as ichthyoplankton 



