9710

• UCREFRP Catalog Number: 9710
• Author: Connolly, P.J., I.G. Jezorek, K.D. Martens and E.F. Prentice.
• Title: Measuring the performance of two stationary interrogation systems for detecting downstream and upstream movement of PIT-tagged salmonids.
• USFW Year: 2008.
• USFW - Doc Type: North American Journal of Fisheries Management
• Copyright Material: YES

417

PERFORMANCE OF PIT TAG INTERROGA nON SYSTEMS

NBC = fish detected on arrays other than array
A = (Sb + Sc+ She)
VA = fish undetected by array A, estimated as
(NA X NBC) / NABC

The detection efficiency of array A (P A) was then
derived from the equation

PA = NA/(NA + VA).

The detection efficiencies for arrays Band C were
calculated in the same fashion. The detection efficiency
for the entire system (P) was then calculated as

P = I - [(1 ~ PA) X (1 - PE) X (I ~ PC)].

Appendix 2: Estimation of the Variance of' the Detection Efticiency

To calculate the detection efficiency, variance (V),
and standard eITor (SE) for the entire interrogation
system, we used a likelihood model available in the
Lady et al.'s (2003) USER program; the variance and
SE were estimated using the delta method (Seber
1982:7-9).
Following the delta method, the variance is calcu-
lated as

n (a )2
V[g(x)] = L: var[xd a~

1=1

~~ (ag) (ag)
+2 L..."L..."COV[Xi,Xj] ~ ~.
i<j ax, ax,

The standard error (SEp) is calculated as

SEp = {SE~A[(PB ~ 1)(Pc - 1)]2
2 ^ ^. 2
+ SEj.H[(PA ~ 1) X (Pc ~ I)]
2 ^ ..^ 2
+ SEpcl(PA ~ I)(PB - 1)]
+ 2 {[COVPA' PB(PB - 1)(Pc - I )(PA - 1)
X (Pc - I)]
+ [covPA,Pc(PB - I)(Pc -1)(PA - I)
X (PH - I)]
+ [covPB,Pc(PA - 1)(Pc - I)(PA -1)
X(PB - 1)]}1/2;

P A = the estimated detection efficiency of array
A,
P B = the estimated detection efficiency of aITay
B,
Pc = the estimated detection efficiency of array
C,
SEpA = the standard error of the detection
efficiency of array A,
SEfrB = the standard error of the detection
efficiency of array B, and
SEpc = the standard error of the detection
efficiency of array C.