from the top of the catch, which came from the last set 
made by the vessel, measured (millimeters, fork length), 
weighed (grams), and sexed. Scales were taken for aging 
(Nicholson and Schaaf in press). In 1964, 1965, and 1971, 
two samples of 20 fish (1 sample per boat) were taken 
daily. From 1966 to 1970, three samples of 20 fish were 
taken. Beginning in 1972, three samples of 10 fish each 
were taken. The location of the last set made by the ves- 
sel was recorded to the nearest 10 minutes of latitude and 
longitude. 
All plants were not sampled equally. Usually, four 
samplers were employed and stationed at locations 
where they could cover two or more plants, arbitrarily 
grouped into ports. Locations were chosen so that plants 
throughout the entire range of the fishery could be 
sampled. The number of samples depended, in part, on 
the duty station of the sampler and ranged from 0 to over 
150 per plant and from 386 to 1,004 per year (Table 4). 
AGE AND SIZE COMPOSITION 
The number of fish landed at each plant was es- 
timated by dividing the total weight of fish landed week- 
ly by the mean weight of fish in the weekly samples, 
either from that plant or from several plants arbitrarily 
grouped together. The number of each age was es- 
timated by multiplying the total estimated number of 
fish by the percentage of each age in the samples. Weekly 
estimates were summed to obtain seasonal estimates. 
Since fish landed at plants in the eastern and western 
ends of the fishery tended to be smaller and younger than 
fish landed at plants in the middle, I summarized the 
data by grouping together plants in the eastern area 
(Mississippi and Florida), central area (Empire to Intra- 
coastal City, La.), and western area (Cameron, La., and 
Sabine Pass, Tex.). 
The total number of fish landed annually varied from 
4,054.73 million in 1966 to 7,796.38 million in 1971 (Table 
5). Age-1 and -2 fish together supplied from 97 to 99% of 
the fish caught, and ages 0 and 3 supplied the remainder. 
Age-1 fish supplied from 59 to 92% of the estimated num- 
ber of fish caught annually, while age-2 fish supplied 
from 6 to 40%. These percentages are about the same, 
whether they are calculated from the estimated number 
of fish caught or from the number of fish in the samples 
(Table 6). The former method of calculating is more 
precise, since it corrects for differences in time and space 
between the ratio of weight of fish landed to number of 
fish in the samples. 
There was remarkable little variation from year to year 
in the length range or mean length, either for individual 
ages or for all ages combined (Table 7). With few excep- 
tions length ranged from about 115 to 215 mm. Mean an- 
nual lengths ranged from 147 to 165 mm for age-1 fish, 
181 to 188 mm for age-2, 201 to 214 mm for fish over age- 
2, and 153 to 172 mm for all ages combined. 
Weight also showed relatively little annual variation, 
ranging from about 20 to 250 g (Table 7). Means ranged 
from 65 to 101 g for age-1 fish, 122 to 148 g for age-2, 170 
Table 5.—Estimated number (in millions) of Gulf menhaden at each 
age landed annually, 1964-73, at plants in eastern area (Mississippi 
and Florida), central area (Empire to Intracoastal City, La.), and 
western area (Cameron, La., and Sabine Pass, Tex.). 
Plant Age 
Year location 0 1 2 3 Total Percent 
1964 Eastern 0.52 1,194.52 219.84 5.65 1,420.53 31 
Central 0.33 744.39 768.45 88.23 1,601.40 34 
Western 5.42 1,196.65 376.86 18.04 1,596.97 35 
Total 6.27 3,135.56 1,365.15 111.92 4,618.90 100 
1965 Eastern 0.35 1,702.82 297.33 8.34 2,008.84 34 
Central 41.01 1,830.84 627.35 62.04 2,561.24 43 
Western 5.27 1,354.41 41.58 1.01 1,402.27 23 
Total 46.63 4,888.09 966.26 71.39 5,972.35 100 
1966 Eastern 5.13 846.22 193.10 7.00 1,051.45 26 
Central 39.17 858.08 413.77 18.53 1,329.55 33 
Western 2.54 1,422.49 243.26 5.44 1,673.73 41 
Total 46.84 3,126.79 850.13 30.97 4,054.73 100 
1967 Eastern 1.32 1,007.79 84.97 4.34 1,098.42 25 
Central 17.38 1,759.82 198.98 6.21 1,982.39 44 
Western 0.00 1,361.63 25.93 0.00 1,387.56 31 
Total 18.70 4,129.24 309.88 10.55 4,468.37 100 
1968 Eastern 0.00 463.78 276.61 4.46 744.85 18 
Central 23.87 1,105.98 529.02 21.22 1,680.09 40 
Western 11.53 1,741.75 44.36 1.53 1,799.17 42 
Total 35.40 3,311.51 849.99 27.21 4,224.11 100 
1969 Eastern 3.16 1,320.30 150.70 6.68 1,480.84 22 
Central 7.62 2,309.13 628.31 21.77 2,966.83 44 
Western 0.00 2,137.41 232.04 1.94 2,371.39 34 
Total 10.78 5,766.84 1,011.05 30.39 6,819.06 100 
1970 ~=Eastern 0.89 690.35 299.14 2.51 992.89 19 
Central 20.89 1,050.08 1,416.42 26.07 2,513.26 48 
Western 27.60 1,515.92 481.62 5.84 2,030.98 33 
Total 49.18 3,256.35 2,197.18 34.42 5,537.13 100 
1971 Eastern 1.75 952.68 532.99 65.88 1,453.30 19 
Central 7.21 2,486.21 988.76 95.04 3,577.22 46 
Western 16.30 2,424.43 316.32 9.01 2,766.06 35 
Total 25.26 5,763.32 1,838.07 169.73 7,796.58 100 
1972 Eastern 788.13 171.57 11.56 971.26 20 
Central 15.31 717.13 1,223.77 52.65 2,008.86 41 
Western 2.26 1,640.99 220.33 7.43 1,871.01 39 
Total 17.57 3,146.25 1,615.67 71.64 4,851.13 100 
1973. Eastern 55.66 432.33 224.56 9.39 721.94 17 
Central 1.56 1,246.38 656.45 94.92 1,999.31 47 
Western 0.00 1,333.64 201.64 5.17 1,540.45 36 
Total 57.22 2,012.35 1,082.65 109.48 4,261.70 100 
Mean total 31.39 3,953.63 1,208.60 66.79 5,260.41 
to 217 g for fish over age-2, and 74 to 117 g for all ages 
combined. 
The contribution of each age group to the total weight 
of the catch was estimated by multiplying the number of 
fish caught at each age by the mean weight of fish in the 
samples. Two age groups, 1 and 2, accounted for over 
95% of the total weight of the catch. The annual varia- 
tion ranged from 95.0 to 99.3%. Age-1 fish contributed 
from 49 to 88%, and averaged 63% for the 10-yr period. 
Age-2 fish contributed from 12 to 50% and averaged 34%. 
Age-3 fish contributed an average of 2.6%, and age-0 fish 
0.2% (Table 8). 
