Stock Assessment of Connecticut River Shad: Examination of Fishing and Predation Effects on the Recent Stock Decline



Download 0.5 Mb.
Page5/9
Date31.03.2018
Size0.5 Mb.
#44219
1   2   3   4   5   6   7   8   9

A 488,000 fish 196,000 fish

r2 0.88


Approximate Equilibrium Overfishing Thresholds

______________________________________________________________________________________


Parameter Mean 95% Confidence Limits
----------------------------------------------------------------------------------------------------------------------------------

avFmsy 0.39 0.23 - 0.55


avFcoll 1.41 1.32 - 1.48
avBmsy 470,000 fish 462,000 - 494,000 fish


Table 8. Striped bass consumption rate (Mp), total fishing mortality (FT), annual Fmsy, annual run size at MSY (Nmsy*1000), shad consumed annually by striped bass (Dt), ratio of fishing mortality (FRZ) to predation (Mp), annual riverine landings (SHADTOTR*1000), ratio of landings to predation loss (FRCC) and sum of fishing + predation mortality (RIVMORT).




YEAR

Mp

FT

FMSY

NMSY

Dt

FRZ

SHADTOTR

FRCC

RIVMORT

1981

0.0523

0.2806

0.5377

497.61

43.52

0.7953

167

0.7933

0.3328

1982

0.0537

0.2330

0.5363

496.19

47.36

0.7267

125

0.7252

0.2868

1983

0.0423

0.1692

0.5477

490.19

63.69

0.7608

198

0.7566

0.2114

1984

0.0546

0.1886

0.5354

489.85

64.62

0.7042

150

0.6989

0.2432

1985

0.0661

0.2915

0.5239

497.22

44.57

0.7260

117

0.7242

0.3576

1986

0.0788

0.4411

0.5112

494.32

52.45

0.8097

213

0.8024

0.5199

1987

0.0572

0.4696

0.5328

502.24

30.90

0.8436

156

0.8347

0.5268

1988

0.1256

0.3478

0.4645

484.78

78.39

0.6088

115

0.5947

0.4734

1989

0.1345

0.2143

0.4555

465.01

132.18

0.4951

121

0.4779

0.3488

1990

0.0820

0.2095

0.5080

489.37

65.90

0.5667

83

0.5574

0.2915

1991

0.0577

0.1858

0.5323

488.54

68.17

0.6715

133

0.6612

0.2435

1992

0.0488

0.1428

0.5412

484.60

78.89

0.6945

171

0.6843

0.1917

1993

0.1001

0.2228

0.4899

485.94

75.25

0.5862

99

0.5681

0.3228

1994

0.1674

0.3692

0.4226

493.90

53.58

0.6168

77

0.5897

0.5366

1995

0.1385

0.2825

0.4516

498.15

42.03

0.4691

35

0.4544

0.4209

1996

0.2047

0.1355

0.3853

459.90

146.08

0.2084

35

0.1933

0.3402

1997

0.1967

0.1507

0.3933

463.51

136.26

0.2320

38

0.2181

0.3474

1998

0.1595

0.2777

0.4305

474.25

107.03

0.2792

39

0.2671

0.4372

1999

0.1777

0.1669

0.4123

480.78

89.28

0.1752

17.6

0.1647

0.3447

2000

0.3329

0.1785

0.2571

456.68

154.82

0.2211

38.5

0.1992

0.5113

2001

0.3413

0.1057

0.2487

401.30

305.45

0.0853

24.2

0.0734

0.4470

2002

0.4578

0.1470

0.1322

375.93

374.46

0.1320

46.2

0.1098

0.6048

2003

0.5018

0.1458

0.0882

396.92

317.39

0.1480

44

0.1218

0.6476

2004

0.5703

0.1542

0.0197

421.18

251.39

0.1206

26.4

0.0950

0.7244

2005

0.5809

0.1928

0.0091

454.53

160.69

0.1632

24.2

0.1309

0.7737



Appendix 1. Annual Atlantic herring (ATH) landings (pounds*1000), pounds of catch subsampled for bycatch, number of shad in subsampled catch, fraction of shad in subsample, coast-wide shad discards (ATH*fraction of shad)/4.5lbs(ave weight per shad) (N*1000) and shad bycatch from the Connecticut River (10% of coast-wide discards) (N*1000).





Download 0.5 Mb.

Share with your friends:
1   2   3   4   5   6   7   8   9




The database is protected by copyright ©ininet.org 2024
send message

    Main page