ELEFAN ICLARM EEFLAN I,II,III,IVEEFLAN 0

eeflan METHODS TO ANALYSE a widely used method to fit von-Bertalanffy Growth Function (VBGF) using length frequency data for data-poor fisheries.

1. ELEFAN Kola Akhila 190804230037

2. Introduction The ELEFAN system ( Electronic length Frequency Analysis ) was developed by ICLARM in response to the need for robust methods for analysis of length frequency data and the availability of cheap microcomputers. This system consists of five programmes
ELEFAN O
ELEFAN I
ELEFAN II
ELEFAN III
ELEFAN IV

3. ElEfan 0 This is the basic system used to create and modify length frequency data files for the use of other four programmes. ELEFAN I to IV will be using length frequency data created by ELEFAN-O

4. ELEFAN-I Developed by Pauly and David (1987). This programme is used to estimate the growth parameters of fish or invertebrates. Growth oscillations of fish can be correlated with selected environmental parameters.

5. ELEFAN – II It performs a variety of computation of which the following are the main ones.
1. Estimation of total mortality (Z) and derived quantities from the straight, descending arm of a length converted catch curve. 2. Estimation of probabilities of capture by length and mean length at first capture (Lc) from the ascending left arm of a length converted catch curve.

6. 3. Expressions of seasonal changes in recruitment intensity in the form of graphical recruitment pattern.
It requires no inputs other than growth parameter estimates and length frequency data.

7. ELEFAN – III It incorporate 3types of Virtual Population Analysis (VPA). VPA – I Estimates standing stock (in numbers) and fishing mortalities by time intervals. VPA – II This programme is used to estimate standing stock (in number) and fishing mortabilities by length class in a stock with age distribution.

8. VPA – III Provides estimates of standing stock and fishing mortalities by month by length.

It requires monthly catch data in addition to length frequency and growth parameters as input.

9. ELEFAN IV This programme provides gear selection parameters (Tc the probability of capture by length class) and can be used to estimate or and probabilities of recruitment by length class from catch samples.