Table 2.—Catch (metric tons) and number of length-frequency samples 
of skipjack tuna by NMFS area-month strata. Samples substituted 
in strata without samples are identified in parentheses. 
Month - year Catch Samples Catch Samples Catch Samples 
(tons) (tons) (tons) 
(July 51) 
January 1974 
February 1974 
March 1974 
May 1970 
1972 
June 1970 
1972 
1974 
July 15969 
1970 
1971 
1972 
1973 
1974 
August 1968 
1969 
1970 
1971 
1972 
1973 
1974 
September 1968 
1969 
1970 
197] 
1972 
1973 
1974 
October 1968 
1969 
1970 
1971 
1972 
1973 
1974 
November 1968 
1969 
1970 
1971 
1972 
1973 
1974 
December 1974 
(July-51) 
(July-51) 
(June-51) 
2 
5 
(July-51) 
(June-51) 
(June-51) 
(July-51) 
3 
(July-51) 
] 
(July-51) 
2 
(Sept-51) 
(Sept-51) 
19 
7 
28 
10 
1 
(Oct-51) 
(Sept-51) 
9 
2 
13 
6 
(Oct>52) 
(Nov-51) 
(Oct-53) 
(Sept-51) 
(Sept-52) 
] 
5 
(Oct-53) 
6 
7 
(Oct-52) 
] 
] 
(Oct-53) 
] 
] 
5 
(Nov.-53) (Oct>52) 
2 
] 
(Dec-52) 
(Nov.-51) 
yellowfin tuna according to the length-frequency distribution of the 
W =a(2:18) <10'458) 22 ith sample. 
skipjack tuna 4. A weighted average weight (w) of fish in all the 
bi af rn (S,GL 2410 se db samples of a stratum was estimated with M; as the 
1eeye une weighting factor, 2 = 2(M_w,)/=M. : 
Ww =10225 XG 10 see) et 
5. The number of fish (N) in the total catch (C) of a 
stratum was estimated with N = C/w. 
2. Average weight was used to convert the well tonnage 6. The length-frequency distributions of all M,’s of a 
. ul bee foe a Maal eS) ETE Sr stratum were pooled and the pooled frequency dis- 
of fish (M; = 5 /0; ). tribution was used to estimate the length com- 
3. M_ is distributed proportionately by 2-cm intervals, position of N. 
