Fish Population Dynamic and Stock Assessment (2+1)

Solution for both trawl net and purse seine

1. Relative CPUE for both gears

R(y) = $${Yield (Y1)\timesRelative CPUE + Yield (Y2) \timesRelative CPUE}\over{Yield (Y1) + Yield (Y2)}$$

1. R (1998) = $${(70\times0.9912) + (250 \times1.0753)}\over {70 + 250}$$ = 1.0569

2. R(1999) = 0.9581

3. R(2000) = 0.9107

4. R(2001) = 1.1362

Sl.No.	Year	YT	R(y)	Relative effort = YT / R(y)
1.	1998	3000	1.0569	2838.4899
2.	1999	4000	0.9581	4174.9295
3.	2000	7500	0.9107	8235.4233
4.	2001	6000	1.1362	5280.7604
			Total	20529.6031

Mean YT/R = 20529.6031 / 4

$$\overline{YT}$$ /R=5132.4008

Calculation of normalized relative effort

E.g. for the year ‘Y’ is

E(Y) = $${YT(Y)/}\over {Mean\overline{YT}/R$$ Relative effortmean relative effort

1. E (1998) = 2838.4899 / 5132.4008 = 0.5537

2. E(1999) = 0.8134

3. E(2000) = 1.6046

4. E(2001) = 1.0289