CalCOFI Reports, Vol. 11, 1967 - California Cooperative Oceanic ...

40g .a-CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS1944-45 - 01943-44 - 01942.63 - A19Al-42 - 01940-41 - mccc///0 -c I t 1 / I I I I I I 1J 10 20 30 40 50 60 70 eo 90 (00 110 120LENGTH OF FISH (U IN MMFIGURE 10. Relationship between standard length of fish and scale radius in Victorian specimens of E. australis. All scales were taken from the samepart of the fish and measured in the same way. Regression lines are based on the material of all year-classes combined. Far further explanationsee text (from Blackburn 19500).Blackburn (1950 a), who analyzed the values in variousways exemplified by Table 2 (where L is actualfish-length at capture).Table 2 shows that intermediate lengths are consistentlyhigher in younger age-groups than in older ;it is believed that this is a result of over-representationof comparatively large fish in the samples of theyounger age-groups from which scales were available,because scales are more deciduous in small fish thanin large ; consequently, it is believed that the Ln meansfrom the older age-groups are the most reliable. Thebest available estimates of mean L1, Lz, L3, Lg, and L5are therefore 53,65,77,93, and 104 mm for GippslandLakes fish; L1, Lz, and L3 are slightly lower (50, 62,and 74 mm) for fish of Port Phillip, which is a salinebay about 170 miles west along the Victorian coastfrom Gippsland Lakes. These data are quantitativelymeager but qualitatively very good. They may be combinedto give the following estimates of mean lengthof Victorian anchovies at successive ages :0.5 yems- 50 mm1.5 years- 62 mm2.5 years- 75 mm3.5 years- 90 mm4.5 years-102 mmNo estimate is given for 5.5 years because only onefish of that age, and none that were certainly older,was found. The greatest length recorded for E.australis is 136 mm, so older fish may well exist.These findings agree fairly well with those of Table1, in which allowance must be made for growth inTABLE 2E. AUSTRALIS, VICTORIAN LOCALITIES MEANS OF CALCULATED INTERMEDIATE LENGTHS (11, 12 EX.) FOR SUCCESSIVE AGE-GROUPS,WHERE n IS NUMBER OF FISH AND L IS THEIR MEAN LENGTH AT CAPTURE; FOR FURTHER EXPLANATION SEE TEXT. (FROM BLACK-BURN 1950~1).L1LaLaL4L6AgeGroupMean Mean nLl LMean Mean nLz LMean Mean nL% LMean Mean n Mean Mean nLk L L6 LA. Port Phillip Bay 1234B. Gippsland Lakes 1234555.87 61.40 3254.07 71.60 10152.23 78.23 2649.91 86.73 1153.00 68.00 156.21 83.14 1453.35 92.35 4653.23 100.48 4853.00 104.58 17_-70.4; 75.ii 4365.60 78.24 2561.91 86.73 11__ _- --72.00 83.25 1268.65 92.25 4866.50 100.71 4464.93 104.40 15I__85.6 93.46 3084.91 100.76 46 96.59 103.0077.27 103.60 15 92.82 104.31-- -- --