0.0 



0.5 



.0 



2.0 



2.5 



URIC ACID (MILLIGRAMS PERCENT) 



Figure 7. — Uric acid of blood of adult pink salmon ir 

 three stages of maturity. (F, females; M, males; 

 single asterisk, early run; double asterisk, late run.) 



as an end product of purine metabolism, a de- 

 cline in purine metabolism at spawning is indi- 

 cated, and females maintain a higher level 

 longer than males. 



UREA 



The variations in the concentration of urea 

 among individual specimens from an area were 

 so great that no trend is apparent for this 

 blood component, which is the end product of 

 nitrogen metabolism. Lysaya (1951) noted 

 increasing concentrations as spawning ap- 

 proached and attributed death of pink and 

 chum salmon to urea poisoning. 



CREATININE 



No data are available on the concentrations 

 of creatinine in blood samples from fish in the 

 prespawning stage, and no trend is indicated 

 by the values for the other groups. Creatinine 

 is sometimes considered an end product of 

 tissue catabolism, which is a dominant process 

 in the fish sampled here. The values I found, 

 however (table 2), are similar to those de- 

 termined for smallmouth bass by Shell (1961) 

 and for carp (Cyprinus carpio) and brook 



trout {Salvelinus fontinalis) by Field, Elveh- 

 jem, and Juday (1943) for fish in which cata- 

 bolism was not high. 



SUMMARY AND CONCLUSIONS 



Blood samples were taken from adult pink 

 salmon collected at three stages of maturation 

 during their migration to the spawning 

 grounds — in the ocean actively migrating, mill- 

 ing in the estuary of a spawning stream, and 

 in fresh water on the spawning grounds. 



Basic hematological characteristics, includ- 

 ing specific gravity, packed-cell volume, ery- 

 throcytes, hemoglobin, corpuscular volume, 

 corpuscular hemoglobin, and corpuscular hemo- 

 globin concentration, were determined. Statis- 

 tical analyses indicated no significant differ- 

 ence among groups of fish. 



The concentrations of several components of 

 blood indicate that several changes accompany 

 migration and maturation. As pink salmon 

 mature, utilization of protein reserves (evi- 

 denced by lowered albumin and globulin levels 

 in females) may result from rapid building of 

 egg ti.ssue. Glucose levels declined, especially in 

 females. Cholesterol concentrations also de- 

 clined, although lipid phosphorus rose in both 

 sexes ; the increase was especially noticeable in 

 females. Lipid phosphorus may play an in- 

 creasingly important part in energy transfer 

 as salmon mature. 



The pink salmon from the spawning stream 

 were from two distinct components of the run 

 — the early and the late. The late spawners had 

 significantly higher concentrations of choles- 

 terol and uric acid, but lower levels of glucose 

 and lipid phosphorus. I do not know if these 

 differences are due to intrinsic genetic factors 

 or are induced by extrinsic environmental 

 factors. 



I could see no trend in urea or creatinine 

 concentrations at the three stages of maturity. 



ACKNOWLEDGMENTS 



David Boye and Mrs. Frances Pierce helped 

 with the statistical comparisons. Theodore R. 

 Merrell, Jr., and several other staff members 

 at the Bureau of Commercial Fisheries Bio- 

 logical Laboratory, Auke Bay, Alaska, aided in 

 collecting samples. This work was financed by 



BLOOD OF ADULT PINK SALMON 



201 



