RECRUITMENT AND 
RELATIVE ABUNDANCE 
Fish usually enter the fishery at age-1 at a minimum 
size of about 120 mm, although some age-0 fish enter at 
about the same size in September and October. Since 
some age-l fish are still less than 100 mm in July, as 
shown by catch samples, a year class probably is not fully 
recruited until August or September. The removal of 
large and the recruitment of small age-1 fish during the 
fishing season tends to supress the amount of increase in 
the mean and modal lengths during the fishing season 
relative to actual growth. 
If age groups are distributed equally in time and space 
throughout a fishery and if the distribution of fishing ef- 
fort does not change each year, the catch per unit of ef- 
fort (CPUE) for each age group is an estimate of relative 
year class abundance. Since these conditions are closely 
approximated in the Gulf menhaden fishery, I based es- 
timates of year class abundance on the CPUE of each age 
group. As a measure of effort, I used the adjusted vessel 
week? which was calculated from the CPUE of a selected 
group of vessels and the total catch of all vessels. 
For the period covered, there was relatively little varia- 
tion in year class abundance (Table 12). The total CPUE 
of all ages in a year class combined ranged from 2.577 
million fish per week for the 1965 year class to 5.377 mil- 
lion for the 1968 year class, with a mean of 3.742 million 
for all years. The most abundant year classes appeared 
to be the 1964, 1968, and 1970, the least abundant the 
1965 and 1971. On the basis of the CPUE of age-2 fish 
only, the 1962 year class also was probably strong. 
There also was little variation in overall abundance. 
The CPUE for total number of fish, regardless of age, 
averaged 3.63 million for the 10 yr and ranged from 2.95 
(1973) to 4.60 million (1969). Years of greatest relative 
abundance were 1965, 1969, and 1971 (4.42, 4.60, and 
4.38 million, respectively); years of least abundance were 
1966, 1972, and 1973 (3.02, 3.01, and 2.95 million, respec- 
tively). 
*Nicholson, W. R. 1977. Fishing effort, mortality, and MSY in the 
Gulf menhaden, Brevoortia patronus, purse seine fishery. Unpubl. 
manuscr., 20 p. 
& U.S. GOVERNMENT PRINTING OFFICE: 1978—-799-953/11 REGION 10 
Table 12.—Catch per unit of effort (mil- 
lions of fish) of Gulf menhaden, at each 
age, 1962-72 year classes. 
Year 
class Agel Age2 Age3 Total 
1962 = 1.175 0.053 =e 
1963 2.698 0.715 0.023 3.436 
1964 3.618 0.633 0.008 4.259 
1965 2.330 0.227 0.020 2.577 
1966 3.025 0.627 0.021 3.673 
1967 2.442 0.682 0.022 3.146 
1968 3.891 1.392 0.094 5.377 
1969 2.062 1.034 0.045 3.141 
1970 3.241 1.006 0.076 4.328 
1971 1.959 0.750. — -- 
1972 2.088 — — — 
LITERATURE CITED 
ANONYMOUS. 
1918-38. Fishery industries of the United States. U.S. Bur. Fish. 
1939-44. Fishery statistics of the United States. U.S. Fish Wildl. 
Serv., Stat. Dig. 
CHAPOTON, R. B. 
1972. The future of the Gulf menhaden, the United States’ largest 
fishery. Gulf Caribb. Fish. Inst. Proc. 24th Annu. Sess., p. 134- 
143. 
CHRISTMAS, J. Y., and G. GUNTER. 
1960. Distribution of menhaden, genus Brevoortia, in the Gulf of 
Mexico. Trans. Am. Fish. Soc. 89:338-343. 
JUNE, F. C., and J. W. REINTJES. 
1960. Age and size composition of the menhaden catch along the 
Atlantic coast of the United States, 1956; with a brief review of the 
commercial fishery. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 
336, 38 p. 
NICHOLSON, W. R., and W. E. SCHAAF. 
In press. Aging of Gulf menhaden, Brevoortia patronus. Fish. 
Bull., U.S. 
ROBAS, J. S. 
1959. Menhaden purse seining. Jn H. Kristjonsson (editor), 
Modern fishing gear of the world, p. 394-399. Fishing News 
(Books) Ltd., Lond. 
SCHMIDT, P. G., Jr. 
1959a. New purse seining techniques in the menhaden fishery em- 
ploying the power block. Gulf Caribb. Fish. Inst. Proc. 11th 
Annu. Sess., p. 46-50. 
1959b. The Puretic power block and its effect on modern purse 
seining. Jn H. Kristjonsson (editor), Modern fishing gear of the 
world, p. 400-413. Fishing News (Books) Ltd., Lond. 
