148 



15- 

 10 



I 



X 

 CO 



5- 



u 



CQ 



Z 



FISHERY BtJLLETIN OF THE FISH AND WILDLIFE SERVICE 



ALL PRESPAWNERS 



ALL POSTSPAWNERS 



ri , r^ 



MALE PRESPAWNERS 





FEMALE PRESPAWNERS 



234 56789 10 II 12 

 3 -HOUR SEDIMENTATION RATE 

 IN MILLIMETERS 



13 



Figure 1. — Three-hour sedimentation rates for prespawn- 

 ing and postspawning alewives. 



The average for prespawners was 5.9 g. per 100 

 ml. while that for postspawners was 5.3 g. per 

 100 ml. — a reduction in fresh water significant at 

 the 5-percent level with the student 7'-test used for 

 small samples, as well as with the rank sum test. 



SERUM CHLORIDES 



Concentrations of various ions in animal body 

 fluids, particularly in invertebrates, may vai^ 

 with environmental and physiological conditions 

 (Prosser, 1950). The closed circulatoiy system 

 of vertebrates probably effects greater ionic sta- 

 bility tlian is true for invertebrates. Numerous 

 studies of teleost ionic regulation in varying exter- 



nal salinities have been made (reviewed by Fon- 

 taine and Koch, 1950, and Black, 1957). Keys 

 (1933) foimd that seiiim clilorides of eels {An- 

 gtulki angu/Ua) were lower in fresh water than 

 in the sea (480 milligrams per 100 ml. as op- 

 posed to 580 mg. per 100 ml.). Bond, Gary, and 

 Hutchinson (1932) and McFarland and Munz 

 (1958) found that in hagfish {PoU^totrejna stouti) 

 the concentration of blood chloride varied in a 

 linear manner with that of the surrounding me- 

 dimn. Harris (1959) noted a drop in blood chlo- 

 ride from 804 mg. to 683 mg. per 100 ml. when 

 Fundulus heteroclitus were transferred from salt 

 water to fresh. 



I5n 



10 



<n 



PRESPAWNERS 



20 



a. 



CO 



3 



■n 



10 



o-t 



POSTSPAWNERS 



ii. 



—I 

 10 



2 3 4 5 6 7 6 

 GRAMS TOTAL PROTEIN 

 PER 100 CC. SERUM 



Figure 2.— Variation in total serum proteins in alewives 

 before and after spawning. 



