CRD 01-03 Table 11. Two alternative approaches to estimating natural
mortality of silver hake. |
|
Hoenig's regression model (1983) based on maximum observed
age Tmax. |
| Fish: |
ln(Z) = 1.46-1.01*ln(Tmax) |
|
a |
b |
|
|
1.46 |
-1.01 |
|
Time Period |
Tmax |
ln(Z) |
Z |
|
|
1960s-1980s |
9.5 |
-0.81719 |
0.44 |
|
1990s |
5.6 |
-0.28156 |
0.75 |
|
Value for 0.4 |
10.5 |
-0.91629 |
0.4 |
| Pauly's regression model (Quinn and Deriso 1999) using growth
parameters from Helser (1996) and near-bottom temperatures from the NEFSC
autumn survey |
| ln(M) = -0.0152-0.279*ln(Linf)+0.6543*ln(k)+0.4634*ln(C) MAB
is Mid-Atlantic Bight, SGB is southern Georges Bank,NGB is northern Georges
Bank, and GOM is Gulf of Maine. |
|
REGION |
Linf |
k |
Fall Survey |
M |
|
Temperature (C) |
M |
Using 0.5*C |
|
MAB75-80 |
49.44 |
0.307 |
12.423 |
0.49 |
0.36 |
|
MAB82-87 |
38.51 |
0.763 |
12.615 |
0.96 |
0.70 |
|
MAB88-92 |
41.25 |
0.472 |
12.27 |
0.68 |
0.49 |
|
SGB75-80 |
42.23 |
0.369 |
12.61 |
0.58 |
0.42 |
|
SGB82-87 |
35.74 |
0.737 |
12.267 |
0.95 |
0.69 |
|
SGB88-92 |
39.71 |
0.425 |
12.25 |
0.64 |
0.47 |
|
NGB75-80 |
45.13 |
0.323 |
10.666 |
0.49 |
0.35 |
|
NGB82-87 |
38.82 |
0.621 |
11.248 |
0.80 |
0.58 |
|
NGB88-92 |
42.47 |
0.399 |
10.371 |
0.56 |
0.41 |
|
GOM75-80 |
51.48 |
0.254 |
7.59 |
0.34 |
0.25 |
|
GOM82-87 |
44.31 |
0.401 |
7.866 |
0.49 |
0.35 |
|
GOM88-92 |
44.88 |
0.354 |
7.228 |
0.43 |
0.31 |