484 FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Table 8. — Ezperimenl 9: Effects on two size groups of Mugil cephalus of bacteria-free and unialgal Gymnodinium brevis 



cultures, and effects of filtration on the toxicity of bacteria-free cultures 



[1 large mullet and 3 small mullet tested in each container] 



Container 



Material in container 



Distress 

 time ' 



Death time 2 



Number (in millions) 



Gym- 

 nodinium 

 brevis per 



liter ' 



Bacteria per 

 ml.J 



pH3 



Salinity 



»/oo 



Remarks 



Millipore filtrate (HA membrane) of 1 

 liter of bacteria-free O. brevis culture, 

 3.3 million organisms per liter. Two 

 membranes used; first one became 

 clogged. 



Paper filtrate (Whatman No. 40) of 1 

 liter of the same culture that was 

 used to prepare the filtrate in con- 

 tainer 1. 



Both millipore membranes used to 

 prepare filtrate in container 1 eluted 

 in 1 liter of sterile culture medium, 

 which was 1 week old with a pH of 

 7.8. 



Filter-paper disc used to prepare the 

 filtrate in container 2 eluted in 1 liter 

 of sterile medium from same batch as 

 used for elution in container 3. 



Millipore filtrate (HA membrane) of 1 

 liter of sterile culture medium — con- 

 trol for container 1. 



Paper filtrate (Whatman No. 40) of I 

 liter of sterile medium from same 

 batch as used to prepare filtrate in 

 container 5 — control for container 2. 



Millipore membrane used to prepare 

 filtrate in container 5 eluted in 1 liter 

 of sterile medium from same batch as 

 used for elution in container 3 — con- 

 trol for container 3. 



Filter-paper disc used to prepare the 

 filtrate in container 6 eluted in 1 liter 

 of sterile medium from same batch as 

 used for elution in container 3— con- 

 trol for container 4. 



Bacteria-free G. breviis culture 



.do. 



.do. 



.do. 



Sterile culture medium— control 

 containers 9, 10, 11, and 12. 



.do.. 



for 



Autoclaved 85% sea water. 



.do.. 



10-week-old unialgal <7. brevis culture 

 that was not replenished with fresh 

 medium. 



.do.. 



(0:09) 

 0:19 

 0:42 

 1:10 



(0:46) 

 0:34 

 0:44 

 0:55 



(Notknown) 



Not known 



5:00 



5:05 



(0:31) 

 0:36 

 0:37 

 0:38 



(') 

 0:48 

 2:12 



(<) 



(*) 

 Not known 



(*) 



(') 



(') 



0:41 

 (*) 

 (') 



(•) 

 (') 

 (<) 

 (') 



(0:15) 

 0:16 

 0:23 

 0:32 

 (0:16) 

 0:32 

 0:48 

 0:68 

 (0:30) 

 0:42 

 0:43 

 0:43 

 (0:32) 

 0:35 

 0:37 

 0:41 

 (') 

 0:18 

 0:30 

 0:52 

 (Notknown) 

 0:46 

 0:52 

 Not known 

 (Notknown) 

 Not known 

 Not known 

 Not known 

 (Notknown) 

 Not known 

 (') 

 (') 

 (0:12) 

 0:24 

 0:54 

 1:48 

 (0:06) 

 0:12 

 0:14 

 0:24 



(0:14) 

 0:2.5 

 1:27 

 1:44 



(0:54) 

 0:44 

 1:10 

 8:05 



CAVi-WA hr.) 

 6:00 

 6:06 

 5:10 



(0:39) 

 0:42 

 0:42 

 0:42 



(<) 



2:01 

 2:17 



1:13 



(') 

 (') 



(') 

 (') 



(<) 



(') 

 (<) 



(') 

 (<) 

 (') 

 (') 



(0:23) 

 0:42 

 1:45 

 1:64 

 (0:28) 

 1:41 

 2:14 

 2:28 

 (0:41) 

 0:44 

 0:45 

 1:08 

 (0:40) 

 0:45 

 0:45 

 0:45 

 (') 



0:25 



0:33 



1 '38 



(8^2-13^ hr.) 



0:47 



0:56 



2:39 



(14:10) 



8H-13}^ hr. 



8;--2-13H hr. 



iVrlZH hr. 



(8H-13>-2 hr.) 



7:16 



(*) 



W 



(0:14) 

 0:45 

 0:56 

 2:30 

 (0:10) 

 0:15 

 0:20 

 0:25 



2.4 

 (2.3) 



3.1 

 (2.9) 



2.7 

 (2.8) 



3.3 



(1.8) 



2.6 



(2.7) 





 (0. 0050) 



0.000008 

 (0.015) 



0.000001 

 (0. 030) 



0.00010 

 (0. 0044) 



0.000002 

 (in excess of 

 80 millions) 



0.000026 

 (25 to 50 

 millions) 



0. 000012 



(in excess of 

 80 millions) 



} - 



6,6 



5.9 

 (6.4) 



1.3 



(1.4) 



33.3 



33 



30.7 



28.9 



33.2 



33.4 



32.! 



32.1 



33.0 



33.1 



33.0 



33.2 



33.2 



Salinity — ?^ hour after last 

 fish died. 



Some G. brevis passed by 

 the filter paper when it 

 was inadvertently over- 

 flowed. 



Salinity and pH— after 14 

 hours. 



pH— 54 hour, salinity— H4 

 hours after last fish died. 



Salinity— H hour after last 

 fish died. 



Salinity— l?i hours after 

 last fish died. 



Salinity— IH hours after 

 last fish died. 



Salinity, first pH, and 

 second bacterial count- 

 after 14 hours. Second 

 pH (6.4)— after 25 hours. 



Salinity, pH, and second 

 bacterial count— after 

 H'i hours. 



pH— 1 hour, salinity— 2 

 hours after last fish died. 



' Time (hr.: min.) required for fish to show first signs of imbalance. The 

 first distress time listed tor each container, in parentheses, pertains to large 

 mullet (4J* to 51.4 in. long) and the other three distress times pertain to small 

 mullet (1 to Hi in. long). 



' Time (hr.: min.) of cessation of opercular movement. The first death 

 time listed for each container, in parentheses, pertains to large mullet and 

 the other three death times pertain to small mullet. 



' The first G. brevis and bacterial counts listed for each container were 

 obtained from samples taken from the containers before addition of the fish 

 except for containers 17 and 18. For these containers, the sample was with- 

 drawn from the culture before portions were dispensed into containers 17 and 



18. With the exceptions noted under Remarks, samples for the second 0. 

 brevis and bacterial counts, in parentheses, as well as pH and salinity samples 

 were collected cither shortly after the last fish died if all fish died withm 24 

 hours or at the end of the 24-hour experimental period if at least 1 fish 

 survived. . 



I Distress or death did not occur during the 24-hour test period. 



s The large mullet in container 16 probably died of oxygen deficiency. The 

 fish appeared in good condition after 13^* hours and the material in the con- 

 tainer was being aerated. When noticed again 30 minutes later the fish was 

 dying and no air was being pumped into the container at this time. 



