FISHERY BULLETIN: VOL. 71. NO. 4 



(Risebrough et al., 1967; Anas and Wilson, 

 1970; Wolman and Wilson, 1970; Burnett, 

 1971; Shaw, 1971, 1972; Castle and Woods, 

 1972; Munson, 1972; Risebrough, Menzel, 

 Martin, and Olcott-'). 



Two types of apparatus were used: a flowing 

 water system and a static water system. The 

 flowing water apparatus was used for experi- 

 ments in which fish were subjected to different 

 toxicant concentrations. Flowing water miti- 

 gates differential toxicant uptake in experimen- 

 tal aquaria where unequal numbers of organisms 

 are present. The static water apparatus was 

 used to examine differences in congenital 

 (untreated) asymmetry in populations; it em- 

 ployed filters to remove metabolic by-products. 



Flowing Water Experiments 



The experimental apparatus used consisted of 

 10 pairs of 6-liter, solid, molded, all-glass 

 aquaria. One pair of aquaria was used as a con- 

 trol, the other nine pairs had the following p,p'- 

 DDT concentrations: 0.001, 0.01, 0.1, 0.4, 0.7, 1, 

 10, 100, and 500 ppb (parts per billion). Water 

 was gravity-fed from an 18-liter seamless all- 

 glass reservoir tank to a pair of aquaria, thus 

 ensuring that each experimental pair received 

 the same quantity of toxicant. Water levels in 

 the aquaria were maintained at 4 liters by indi- 

 vidual all-glass, air-lift water pumps, each pump 

 having the capacity to remove more water from 

 the aquaria than was entering from the reser- 

 voir. Aquaria were covered with a V4 -inch plas- 

 tic cover, and air was removed by vacuum (dis- 

 charged to the outside of the building) to prevent 

 contamination between tanks. Waste water from 

 each tank was discharged into a central collect- 

 ing tube and deposited into a sealed drain. The 

 water flow to each tank was such that its water 

 was completely replaced daily. 



To obtain the desired toxicant concentrations, 

 as mentioned above, standard solutions of p,p'- 

 DDT in pesticide quality acetone were prepared. 



The quantity of p,p'-DDT in each standard solu- 

 tion was such that when 100 /^l of acetone was 

 dissolved in 18 liters of seawater (the size of our 

 reservoir tanks), the concentration of p,p'-DDT 

 in each reservoir tank was brought to one of the 

 desired experimental concentrations. Filtered 

 seawater was used for these experiments (obtain- 

 ed from the Scripps Institution of Oceanography 

 Aquarium supply). 



Grunion eggs for this experiment were col- 

 lected from Belmont Shore. The eggs were 

 obtained by digging in the sand the morning 

 after a major grunion run. Clutches of eggs were 

 placed in damp sand for an incubation period of 

 10 days. Eggs were hatched by placing handfuls 

 of egg-bearing sand in seawater and agitating 

 for a short period of time. 



The flowing water experiments were begun 

 with two control tanks and two replicate tanks 

 for each treatment. Each tank initially contained 

 approximately 400 fry. Thirty-eight days after 

 hatching (48 days after being spawned), fish in 

 one of the control tanks and one each of the 

 replicate treatment tanks were killed. Fifty-one 

 days after hatching (61 days after being spawned), 

 the remaining fish were killed. 



Static Water Experiments 



The static water experiments consisted of 

 raising grunion fry from different localities in 

 continuously filtered recirculating seawater. 

 Seawater in these tanks was changed weekly. 

 Approximately 400 fry were used from each of 

 three localities, Belmont Shore, Del Mar, and 

 Bahia San Quintin, 200 fry being placed in each 

 of two replicate tanks. Collection of eggs, hatch- 

 ing, and experiment termination periods were 

 identical to those previously described. 



All grunion were fed several times weekly on 

 a diet consisting of newly hatched brine shrimp 

 nauplii. Dead brine shrimp were removed from 

 all tanks daily. Water temperature was ambient 

 (ca. 20° C). No attempt was made to adhere to a 

 light-dark cycle. 



■' Risebrough, R. W., D. B. Menzel, D. J. Martin, and H 

 S. Olcott. 1970. DDT residues in Pacific marine fish. 

 Unpubl. manuscr., 32 p. Bodega Bay Mar. Lab., Bodega 

 Bay, CA 94923. 



Analyses 



Upon termination of each experiment, live 



922 



