FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

The engraulid resource was estimated by DeLury method which required: 1. there were no immigranted groups from other fishing grounds, 2. the period of occurreance and diminishment of each group was in a short time less than one week, and 3. it was intensivly fished. By this method, the fishing rate in the Fan- Liao area in 1990 was as follows: (1) Without considering the natural increment of all groups during the time of estimation, the average fishing rate was 0.714 and the yearly fishing rate was 0.489. (2) With considering the nature increment (daily growth rate 0.783mm/day, the relationship of body length (X) and body weight (Y) was Y=0.00031X3.741 and body length at the first day of estimation were 16mm,19mm,23mm), the average fishing rates were 0.742, 0.715, 0.691, respectively. In comparison of the two results, the latter that considered the growth of individuals is more closely to the result of the biomass hydrocostic method, which had been applied to same population in the year.