Target Length Calculator
This operator creates a single target variable that reports the calculated target length of each detected target.
It accepts operands with the following data types:
- Single targets
Notes:
- This operator is intended for use with single beam data. Target length in multibeam data is calculated and displayed differently, via the Multibeam target detection operator and the Target conversion operator.
- Target lengths from a single target echogram
- About target properties
Settings
The Target Length Calculator Variable Properties dialog box pages include (common) Variable Properties pages and these operator pages.
Operands page
Target length page
|
Setting |
Description |
|
Factor A |
Enter the species specific factor A. |
|
Factor B |
Enter the species specific factor B. |
Algorithm
The Target length calculator operator estimates Target length (L) in cm from target strength (TS) using two species specific constants A and B, and is calculated using the (inverse of the following) equation:
TS = A log(L) + B
The table below lists values of A and B for some fish species.
|
Species |
A (Slope ) (dB) |
B (Intercept) (dB) |
|
Basketwork eel (Diastobranchus capensis)1 |
20.1 |
-70.1 |
|
Black javelinfish (Mesobius antipodum)1 |
25.9 |
-84.5 |
|
Javelinfish (Lepidorhynchus denticulatus)1 |
20.0 |
-73.5 |
|
Black oreo (Allocyttus niger)1 |
14.9 |
-62.1 |
|
Smooth oreo (Pseudocyttus maculatus)1 |
27.6 |
-87.7 |
|
Notable rattail (Caelorinchus innotabilis)1 |
35.8 |
-93.9 |
|
Serrulate rattail (Coryphaenoides serrulatus)1 |
34.6 |
-93.8 |
|
Four rayed rattail (Coryphaenoides subserrulatus)1 |
26.3 |
-84.6 |
|
Ridge scaled rattail (Macrourus carinatus)1 |
27.9 |
-80.8 |
|
White rattail (Trachyrincus aphyodes)1 |
28.8 |
-80.2 |
|
Robust cardinalfish (Epigonus robustus)1 |
34.4 |
-83.6 |
|
Deepsea cardinal fish (Epigonus telescopus)1 |
34.6 |
-86.6 |
|
Johnson’s cod (Halargyreus johnsoni)1 |
22.5 |
-70.3 |
|
Ribaldo (Mora moro)1 |
21.7 |
-66.7 |
|
Hake (Merluccius australis)1 |
27.1 |
-83.5 |
|
Hoki (Macruronus novaezelandiae)1 |
18.0 |
-74.0 |
|
Orange roughy (Hoplostethus atlanticus)1 |
16.2 |
-74.3 |
|
Walleye pollock2 |
20 |
-66 |
|
Cod at 38kHz3 |
24.6 |
-60.8 |
|
Sprat at 38kHz3 |
17.2 |
-66.6 |
|
White perch4 |
26.48 |
-69.45 |
|
Striped bass4 |
15.37 |
-56.26 |
|
Yellowfin tuna (Thunnus albacares)5 |
34.0 |
-92.5 |
References:
- McClatchie and Coombs (2005)
- Foote and Traynor (1988)
- Nakken and Olsen (1977)
- Hartman and Nagy (2005)
- Wu et al. (2002)