Fig. 1.1 Annual commercial landings of masu salmon in Hokkaido during 1970-2002.

Fig. 1.2 Number of hatchery-reared masu salmon stocked in Hokkaido, 1980-2001.

Fig. 2.2a Masu salmon landed at the Muroran Fish Market, Hokkaido. Fig. 2.2b Marked masu salmon landed at the Muroran Fish Market, Hokkaido. The upper one is unmarked fish, and the lower one is maked fish (adipose, dorsal, and anal fins clipped).

Table 2.2 Date, site, number, mean weight, and mark of masu salmon smolts s0in 1993-1995 1 Numbers of total marked masu salmon counted by samplers at fish markets (i.e. does not imply total recoveries).

Fig. 2.4 Estimated number of marked masu salmon landed at each market in 1996. The arrows indicate stocking sites.

Fig. 2.5 Estimated number of marked masu salmon recovered in relation to total number of masu salmon landed at each market in 1996 (except for Otobe and Shosanbetsu fish markets).

Table 2.3 Number of marked fish recovered and mark ratio at each fish market surveyed in 1996

Table 2.4a Estimated number of total masu salmon landed in the coastal waters of western Hokkaido in 1994-1996 (without stratification of markets) 1 Within -variance: variance accounts for the variation of fish landed among landing days 2 Between -variance: variance accounts for the variation of fish landed among fish markets Table 2.4b Estimated number of marked masu salmon landed in the coastal waters of western Hokkaido in 1994-1996 (without stratification of markets) 1 Withi n-variance: variance accounts for the variation of fish landed among landing days 2 B etween-variance: variance accounts for the variation of fish landed among fish markets

Fig. 2.6 Effects of stratification of fish markets on the coefficient of variation for the estimates. Explanatory notes show the hatcheries of origin and the years of recoveries.

2 B etween-variance: variance accounts for the variation of fish landed among fish markets 1 Within -variance: variance accounts for the variation of fish landed among landing days 2 Between -variance: variance accounts for the variation of fish landed among fish markets

A) Otobe Hatchery stock recovered in 1996 B) Shosanbetsu Hatchery stock recovered in 1995 Fig. 2.7 Relation between the numbers of fish markets surveyed and survey days for SE of the marked masu salmon recovered. *Present value of the estimate of SE. (A) Otobe Hatchery stock recovered in 1996. (B) Shosanbetsu Hatchery stock recovered in 1995.

Table 2.7 Cost and financial returns for hatchery-reared masu salmon fry and smolts. Ranges in parentheses.

Fig. 2.9 Mean weight of marked masu salmon landed in western Hokkaido in 1996. Vertical bar indicates standard deviation.

Table 3.1 Detailed results from investigating parameters of each model to illustrate the relationship between smolt size of hatchery-reared masu salmon at release and subsequent recovery rate by commercial fisheries (for total smolts) 1 Xi is mean weight of hatchery-reared masu salmon at release, and Yi is estimated recovery rate by commercial fisheries.

Fig. 3.1a Relationship between recovery rate by commercial fisheries and mean weight of masu salmon smolts at release. Regression line was estimated for total smolts. Fig. 3.1b Relationship between recovery rate by commercial fisheries and mean weight of masu salmon smolts at release. Regression lines were estimated for the Shosanbetsu Hatchery stock (---) and the Kumaishi and Otobe Hatcheries stocks (-), separately.

Table 3.2 Detailed results from investigating parameters of each model to illustrate the relationship between smolt size of hatchery-reared masu salmon at release and subsequent recovery rate by commercial fisheries (for smolts stocked from Shosanbetsu)

Table 3.3 Detailed results from investigating parameters of each model to illustrate the relationship between smolt size of hatchery-reared masu salmon at release and subsequent recovery rate by commercial fisheries (for smolts stocked from Kumaishi and Otobe)