All four are linear regressions having a 

 constant rate of increase of head length to body 

 length. The percentage decrease in head length 

 with increase in body length, noted by Tester, 

 results from the fact that the y -intercepts (a 

 above) differ considerably from zero. Both the 

 slopes and y-intercept of the four regressions 

 differ from each other, but it is not possible to 

 assess the significances of these differences 

 without having the original data instead of aver- 

 age values for determining the regressions. 

 Whether the differences are age connected or 

 whether they reflect the variability in this char 

 acter between year classes is a moot point. 



From a consideration of the differences 

 found in meristic and morphometric characters 

 and from additional evidence from age composi - 

 tion, Tester concluded that "intermingling of the 

 runs of herring in British Columbia is limited in 

 extent and that the total stock is divided into a 

 number of essentially discrete units or local 

 populations. Differences in one or several char- 

 acters segregates the populations in the following 

 localities or groups of localities: Point Grey; 

 Granite Bay; Saltspring Island- Departure Bay- 

 Nanoose Bay; Bartcley Sound-Sydney inlet; Nootka 

 Sound-Kyuquot Sound; Quatsino Sound; Bella Bella; 

 Jap inlet -Butler Cove -Pearl Harbour. There are 

 indication s from age composition that the Sydney 

 inlet run also forms a local population. Similar 

 evidence indicates the presence of a local popula- 

 tion at Skidegate inlet and at Pearl Harbour. The 

 status of Prince Rupert Harbour, Bella Coola, 

 and Pender Harbour herring has not been estab- 

 lished, although it is certain that the latter are 

 not part of the Point Grey run . 



"The designation of these runs or local 

 populations does not preclude the possibility of 

 a slight degree of intermingling between adjacent 

 or closely- situated groups. Because of this 

 possibility and also because of incomplete knowl- 

 edge of the seasonal movements which seem to 

 take place during summer feeding grounds and 

 winter habitats, no attempt is made to define 

 precisely the areas which they occupy. The pos- 

 sibility also exists that further investigation will 

 reveal that any of these populations may be fur- 

 ther divisible into two or more separate units." 

 (Tester, 1937:143-44). 



By the time this report had appeared, 

 British Columbia had entered upon an extensive 

 tagging program, which was to alter some of 

 the conclusions given above. 



Tagging in British Columbia waters .- - Tag- 

 ging of British Columbia herring, begun in 1936, 

 has been continued to date without interruption . 

 The results are found in a series of yearly pub- 

 lications listed in the bibliography. Internal tags 

 of iron plated with nickel or silver of the type 

 developed by Rounsefell and Dahlgren were used. 

 A portion of the tags are recovered at the time of 

 unloading by means of an electronic tag detector 

 placed in a chute or conveyor, but the great 

 majority are recovered from electro -magnets in- 

 stalled in the meal line of herring reduction 

 plants . The former method developed by Dahlgren 

 (1936) is by far the more valuable method of re- 

 covery, for in addition to the tag the fish itself 

 is recovered and can be measured for the second 

 time, aged, sexed, etc . , and exact information 

 can be obtained on area and date of recapture and 

 rate of growth . 



During the period 1936-37 through 1953-54 

 (the last report available) over 737,000 herring 

 have been tagged in British Columbia waters . 

 The great majority of these (over 90 percent) 

 were tagged on the spawning grounds after the 

 commercial season had ended and so are not sub- 

 ject to recapture by the commercial fleet for at 

 least six months following tagging. The average 

 recovery from spring tagged herring has been 

 about 25.7 fish per 1,000 tagged during the first 

 season after tagging, 7.70 fish per 1,000 tagged 

 during the second season after tagging, and then 

 1.90, 0.80, and 0.20 fish per thousand tagged 

 during the three subsequent seasons . 



These recoveries are somewhat lower than 

 those obtained from a tagging experiment on the 

 Pacific sardine. The two experiments are com- 

 parable, as an internal tag was used in tagging 

 sardine, and recoveries were dependent upon 

 electro -magnets placed in fish meal lines. 



The returns are markedly lower than those 

 obtained on hardier, longer lived fish such as the 

 Pacific halibut. Recoveries of halibut tagged in 

 1951, for example, amounted to 199 per 1,000 

 tagged after three seasons, and the recoveries 



54 



