. -1 30 so 60 70 LENGTH _ CMS u In IbtItI ytIyhImiI kIx Ixr Ixnl YEAR CLASSES Fig. 20. Percentage length frequencies, and a partial life curve, for Merluccius merhicciiis. From Hickling, 1933, table IX a. Before this comparison is made, it is necessary to make clear one most important difference between the two stocks: the males of the Patagonian hake are relatively much smaller than those of the European hake. It will be shown that Patagonian hake are some 5-0 cm. smaller than European hake, on the average, when the sexes are lumped together; but although directly comparable data for the sepa
. -1 30 so 60 70 LENGTH _ CMS u In IbtItI ytIyhImiI kIx Ixr Ixnl YEAR CLASSES Fig. 20. Percentage length frequencies, and a partial life curve, for Merluccius merhicciiis. From Hickling, 1933, table IX a. Before this comparison is made, it is necessary to make clear one most important difference between the two stocks: the males of the Patagonian hake are relatively much smaller than those of the European hake. It will be shown that Patagonian hake are some 5-0 cm. smaller than European hake, on the average, when the sexes are lumped together; but although directly comparable data for the separate sexes are not available, it can be shown that males of the Patagonian stock are relatively much smaller than this difference would indicate. Means for each sex of European hake may be obtained from Hickling's table IXa. While the means for the Patagonian stock are not directly comparable with these, the difference between the mean lengths for each sex, in each set of data, may readily be com- puted; and the difference between these differences is probably significant, though this cannot be established statistically. For Patagonian hake the difference is 49-9 cm. for females less 36-4 cm. for males, 13-5 cm. For European hake, with data including a much higher proportion of the smaller individuals of both sexes, it was 34-9 cm. for females less 31-0 cm. for males, 3-9 cm. Moreover, if we take the largest decile of the 1396 Patagonian males, we find that they show a mean length of 46-1 cm., the largest individual was 64 cm. long, and only i % of the total of 50-0 cm. and over. The largest decile of the European males has a mean length of 56-1 cm., while the largest individual age group had a mean length of 767 cm.; and some 7% of the total were 50-0 cm. long and over, in spite of the much greater proportion of small individuals in this series of measurements.
Size: 2424px × 2061px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
