mm; all data - acfm14_1998.pdf (8.081Mb)

Year

Larvae 5-15 mm;

outlier excluded

1

1970 1975 1980 1985 1990 1995 2000 Year

Figure 2.5.1: Influence of an outlier on the resulting MLAI. Inclusion of outlier is presented on the left, exclusion on the right side

Figure 2.6.1

North Sea herring:

IBTS

2-5+

Figure 2.8.1 Herring in Sub-area IV, Divisions Vlld and Illa. Estimates of fishing mortality (+l- 95 c.1.) in population models fitted to the separate indices and the catch at age matrix. Each index is given an equal weight.

The encircled index numbers indicate which indices are used in the final assessment.

1400000

1

^+Acoustic surveys 2-9+

-+- IBTS 2-5+

V) V)

'

_I ₁_1- _-_-_I

1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997

Figure 2.8.2 SSB estimates obtained from model fits with separate indices compared to the SSB estimate in the final assessment

- - - . _ _ _ _ _ _ _ _ r _ _ _ _ _ C - . - - - . -

___,___... * - - - .--,... - - -

___,__,---- _ _ _ . . . I . - -

______,-. ___...--

_ _ _ _ , - - - -

,__...-- __,._._-.---

~ . - I _ _ . _ _ _ _ _ _ _ _ _ _ _ _ ~ , - - -

_ -

^{* -}

- . - _ _ _ _ _ _ _ _ _ _ - r - - _ _ _ _ - c * -

Reference F

Y e a r

Figure 2.8.3 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Upper panel: sum of squares (SSQ) surfaces for the tuning indices. SSBxl refers to the MLAI estimate of total biomass, the age-indices 1 to 4 refer to the acoustic index (l), the IBTS 2-5+ index (2), the IBTS l-ringer index (3) and the MIK 0-ringer index (4).

Lower panel: summary of landings, estimated fishing mortality at reference age 4 (wr), recruitment of 0-ringers and total biomass and spawning biomass at spawning time.

117

Figure 2.8.4 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Final assessment. Upper panel:

selection patterns diagnostics. Top left: contour plot of selection pattern residuals. Top right: two estimated selection patterns S1 (1992-1995) and S2 (1996-1997). Bottom: marginal totals of residuals by year and age. Lower panel:

diagnostics of the fit of the MLAI spawning stock biomass against the estimated SSB. Top left: spawning biomass from the fitted populations (line) and the predicted spawning biomasses from the index observations (triangles +/- standard deviation). Top right: scatterplot and fitted catchability model of spawning biomass from the fitted populations and the tuning index observations. Bottom: residuals as [ln(observed index)-ln(expected index)] plotted 118 against expected values from the fitted populations (left) and time (right).

2.*6 4.0e6 S.2e6 6.4e6

E x p e c t e d Ua lue

. . .

0.9e6 i.9e6 2.926 3.9e6

E x p e c t e d U a l u e

Figure 2.8.5 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Final assessment. Upper panel:

diagnostics of the fit of the acoustic 2-ringer index against the estimated stocknumbers at age 2. Top left: fitted populations at age 2 (line) and the predicted stocknumbers from the index observations (triangles +/- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 2 and the tuning index observations. Bottom: residuals as [ln(observed index)-ln(expected index)] plotted against expected values from the fitted populations (left) and time (right). Lower panel: diagnostics of the fit of the acoustic 3-ringer index against the estimated stocknumbers at age 3. Top left: fitted populations at age 3 (line) and the predicted stocknumbers from the index observations (triangles +/- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 3 and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected index)]

* plotted against expected values from the fitted populations (left) and time (right).

119

Index Ualue

Exmec t ed Ua lue

Expected Ua l& Tine

Figure 2.8.6 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Final assessment. Upper panel:

diagnostics of the fit of the acoustic 4-ringer index against the estimated stocknumbers at age 4. Top left: fitted populations at age 4 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 4 and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected index)] plotted against expected values from the fitted populations (left) and time (right). Lower panel: diagnostics of the fit of the acoustic 5-ringer index against the estimated stocknumbers at age 5. Top left: fitted populations at age 5 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 5 and the tuning index observations. Bottom: residuals as [ln(observed index)-ln(expected index)]

plotted against expected values from the fitted populations (left) and time (right).

0.09e6 0.50e6 0.9ie6 i.32e Index Ua lue

Expected Ualue

Index Ualue

Figure 2.8.7 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Final assessment. Upper panel:

diagnostics of the fit of the acoustic dringer index against the estimated stocknumbers at age 6. Top left: fitted populations at age 6 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 6 and the tuning index observations. Bottom: residuals as [ln(observed index)-ln(expected index)] plotted against expected values from the fitted populations (left) and time (right). Lower panel: diagnostics of the fit of the acoustic 7-ringer index against the estimated stocknumbers at age 7. Top left: fitted populations at age 7 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 7 and the tuning index observations. Bottom: residuals as [ln(observed index)-ln(expected index)]

plotted against expected values from the fitted populations (left) and time (right). 12 1

Index Ualue

Expected Ualue

T i n e

a

Figure 2.8.8 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Final a>w\\rnc.nr. Upper panel:

diagnostics of the fit of the acoustic 8-ringer index against the estimated stocknumbers ~II ~ g c X . Top left: fitted populations at age 8 (line) and the predicted stocknumbers from the index observations crncln2lcs +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age X .~nd the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected index)] plotted against e ~ p c c t c d values from the fitted populations (left) and time (right). Lower panel: diagnostics of the fit of the acoustic Y+ ringer index against the estimated stocknumbers at ages 9+. Top left: fitted populations at ages 9 + (line) and the prediotcd stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at ages 9+ and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected 122 index)] plotted against expected values from the fitted populations (left) and time (right).

f!&

~ x m e c t ed Ua lue

Figure 2.8.9 Autumn spawning herring in Section IV and Divisions VIId and II1,a. Final assessment. Upper panel:

diagnostics of the fit of the IBTS 2-ringer index against the estimated stocknumbers at age 2. Top left: fitted populations at age 2 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 2 and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected index)] plotted against expected values from the fitted populations (left) and time (right). Lower panel: diagnostics of the fit of the IBTS 3-ringer index against the estimated stocknumbers at age 3. Top left: fitted populations at age 3 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 3 and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected index)]

plotted against expected values from the fitted populations (left) and time (right). 123

Y e a r I n d e x V a l u e

a ~ x p e c t e d V a l u e

I n d e x V a l u e

Figure 2.8.10 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Final assessment. Upper panel:

diagnostics of the fit of the IBTS Cringer index against the estimated stocknumbers at age 4. Top left: fitted populations at age 4 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 4 and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected index)] plotted against expected values from the fitted populations (left) and time (right). Lower panel: diagnostics of the fit of the IBTS S+ ringer index against the estimated stocknumbers at ages 5+. Top left: fitted populations at ages 5+ (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted 124 populations at ages 5+ and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected

index)] plotted against expected values from the fitted populations (left) and time (right).

Index Ua lue

Figure 2.8.11 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Final assessment. Upper panel:

diagnostics of the fit of the separate IBTS l-ringer index against the estimated stocknumbers at age I . Top left:

fitted populations at age 1 (line) and the predicted stocknumbers from the index observations (triangles +/- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 1 and the tuning index observations. Bottom: residuals as [ln(observed index)-ln(expected index)] plotted against expected values from the fitted populations (left) and time (right). Lower panel: diagnostics of the fit of the MIK 0-ringer index against the estimated stocknumbers at age 0. Top left: fitted populations at age 0 (line) and the predicted stocknumbers from the index observations (triangles +l- standard deviation). Top right: scatterplot and fitted catchability model of fitted populations at age 0 and the tuning index observations. Bottom: residuals as [In(observed index)-ln(expected index)]

plotted against expected values from the fitted populations (left) and time (right).

125

Y e a r Y e a r

Y e a r

n 1.&6

Y e a r

Figure 2.8.12 Autumn spawning herring in Section IV and Divisions VIId and IIIa. Evaluation of assessment uncertainty using a covariance matrix method with 1000 random draws of all the parameters estimated in the ICA model (e.g. selection patterns, reference fishing mortalities in the separable period, stock numbers in the final year and at the final ages, catchabilities of the survey indices and recruitment in 1998)

.

Upper panel: summary of landings, estimated mean fishing mortality (age 2-6), recruitment of 0-ringers and spawning biomass. Shown are the 5, 25, 50, 75 and 95 percentiles. Lower panel: distribution of spawning stock biomass in relation to MBAL (800.000 tonnes) and the risk of being below MBAL.

126

Figure

2.9.1

The age composition of herring in Divisions IVc and VIId in the Dutch catches from December 1980- 1997.

Figure 2.1 1 . l . North Sea Herring.Stock-recruitment relationship used for the medium-term projecti0ns.A Beverton-Holt model.

Clockwise from top left, first panel: Time series of recruitment (ICA estimates, open squares), expected recruitments (fitted value from Beverton-Holt model) and fitted recruitments (including autocorrelation term). Second panel, the stock-recruit function and the obsewed and expected recruitments plotted in the stock-recruitment plane. Third panel, scatterplot of residuals on time. Fourth panel, scatterplot

In document acfm14_1998.pdf (8.081Mb) (sider 120-136)