Scottish Marine and Freshwater Science Volume 5 Number 10: Updating Fisheries Sensitivity Maps in British Waters

The requirement to display sensitive areas relating to the life history of commercially important fish species in British waters is well recognized and has been used by the Oil and Gas and other offshore industries for over thirty years. An update of thes


3 Fisheries Sensitivity Maps

3.1 Areas of 0 Group Aggregations

There is a set of three maps for each of the selected species:

a) The first map shows the probability of presence of aggregations of 0 group fish; aggregations were determined as detailed in Section 2.1.1. For hake and anglerfish the maps presented here show the probability of presence of 0 group fish and not the probability of presence of aggregations.

The first map also shows information about the performance of the Random Forest model, evaluated by the AUC and kappa statistics, as explained in Section 2.3. Random Forest always showed higher values than MAXENT and, therefore, this model was used to produce the final outputs.
A summary of the performance of every model can be seen in Table 7 and Table 8.

b) The second map shows areas of 0 group aggregations in red, identified as the areas with a probability of presence above the value at which kappa is maximum - as detailed in Section 2.3

This map also shows Presence and Absence source data.

c) The third map shows how the newly defined 0 group aggregation areas compare to the areas defined in Coull et al. (1998), for the species where these were available. Horse mackerel, hake and anglerfish were not included in the Coull (1998) report hence for these three species there are no maps of this kind.

Table 7

Evaluation of models performance: AUC (Area Under the Curve) and kappa statistics, using a random division of the data.

AUC Kappa
Value Performance Value Performance
Cod 0.977 ± 0.018 Excellent 0.682 ± 0.053 Good
Haddock 0.987 ± 0.009 Excellent 0.859 ± 0.043 Excellent
Whiting 0.980 ± 0.005 Excellent 0.823 ± 0.021 Excellent
Norway pout 0.988 ± 0.005 Excellent 0.861 ± 0.023 Excellent
Herring 0.949 ± 0.012 Excellent 0.539 ± 0.033 Good
Mackerel 0.985 ± 0.010 Excellent 0.837 ± 0.057 Excellent
Horse mackerel 0.988 ± 0.004 Excellent 0.848 ± 0.033 Excellent
Sprat 0.988 ± 0.010 Excellent 0.857 ± 0.049 Excellent
Blue whiting 0.997 ± 0.002 Excellent 0.879 ± 0.038 Excellent
Plaice 0.997 ± 0.003 Excellent 0.893 ± 0.030 Excellent
Sole 0.995 ± 0.007 Excellent 0.750 ± 0.096 Excellent
Hake 0.977 ± 0.005 Excellent 0.657 ± 0.034 Good
Anglerfish 0.979 ± 0.013 Excellent 0.667 ± 0.036 Good

Table 8

Evaluation of models performance: AUC (Area Under the Curve) and kappa statistics, using a year-by-year division of the data.

Herring, mackerel and sole were not analysed using this division of data.

AUC Kappa
Value Performance Value Performance
Cod 0.79 ± 0.08 Good 0.19 ± 0.08 Poor
Haddock 0.82 ± 0.08 Good 0.37 ± 0.07 Poor
Whiting 0.83 ± 0.05 Good 0.42 ± 0.08 Good
Norway pout 0.86 ± 0.04 Good 0.38 ± 0.1 Poor
Herring - - - -
Mackerel - - - -
Horse mackerel 0.91 ± 0.07 Excellent 0.51 ± 0.15 Good
Sprat 0.86 ± 0.08 Good 0.33 ± 0.11 Poor
Blue whiting 0.95 ± 0.03 Excellent 0.51 ± 0.18 Good
Plaice 0.96 ±0.03 Excellent 0.67 ± 0.16 Good
Sole - - - -
Hake 0.92 ± 0.05 Excellent 0.47 ± 0.17 Good
Anglerfish 0.97 ± 0.01 Excellent 0.67 ± 0.03 Good

Figure 3: Probability of presence of 0 group aggregations. Cod.

Figure 3: Probability of presence of 0 group aggregations. Cod

Figure 4: 0 group aggregations and areas of Presence/Absence source data. Cod.

Figure 4: 0 group aggregations and areas of Presence/Absence source data. Cod

Figure 5: 0 group aggregation areas and Coull (1998) nursery areas. Cod.

Figure 5: 0 group aggregation areas and Coull (1998) nursery areas. Cod

Figure 6: Probability of presence of 0 group aggregations. Haddock

Figure 6: Probability of presence of 0 group aggregations. Haddock

Figure 7: 0 group aggregations and areas of Presence/Absence source data. Haddock.

Figure 7: 0 group aggregations and areas of Presence/Absence sources data

Figure 8: 0 group aggregation areas and Coull (1998) nursery areas. Haddock.

Figure 8: 0 group aggregation areas and Coull (1998) nursery areas. Haddock

Figure 9: Probability of presence of 0 group aggregations. Whiting.

Probability of presence of 0 group aggregations. Whiting

Figure 10: 0 group aggregations and areas of Presence/Absence source data. Whiting.

Figure 10: 0 group aggregations and areas of Presence/Absence source data. Whiting

Figure 11: 0 group aggregation areas and Coull (1998) nursery areas. Whiting.

0 group aggregation areas and Coull (1998) nursery areas. Whiting

Figure 12: Probability of presence of 0 group aggregations. Norway pout.

Probability of presence of 0 group aggregations. Norway pout.

Figure 13: 0 group aggregations and areas of Presence/Absence source data. Norway pout.

Figure 13: 0 group aggregations and areas of Presence/Absence sources data. Norway pout

Figure 14: 0 group aggregation areas and Coull (1998) nursery areas. Norway pout.

Figure 14: 0 group aggregation areas and Coull (1998) nursery areas. Norway pout

Figure 15: Probability of presence of 0 group aggregations. Herring.

Figure 15: Probability of presence of 0 group aggregations. Herring

Figure 16: 0 group aggregations and areas of Presence/Absence source data. Herring.

0 group aggregations and areas of Presence/Absence source data

Figure 17: 0 group aggregation areas and Coull (1998) nursery areas. Herring.

Figure 17: 0 group aggregation areas and Coull (1998) nursery areas. Herring

Figure 18: Probability of presence of 0 group aggregations. Mackerel.

Figure 18: Probability of presence of 0 group aggregations. Mackerel

Figure 19: 0 group aggregations and areas of Presence/Absence source data. Mackerel.

Figure 19: 0 group aggregations and areas of Presence/Absence source data

Figure 20: 0 group aggregation areas and Coull (1998) nursery areas. Mackerel.

Figure 20: 0 group aggregation areas and Coull (1998) nursery areas. Mackerel

Figure 21: Probability of presence of 0 group aggregations. Horse mackerel.

Figure 21: Probability of presence of 0 group aggregations. Horse mackerel

Figure 22: 0 group aggregations and areas of Presence/Absence source data. Horse mackerel.

figure 22: 0 group aggregations and areas of Presence/Absence source data. Horse mackerel

Figure 23: Probability of presence of 0 group aggregations. Sprat.

Figure 23: Probability of presence of 0 group aggregations. Sprat

Figure 24: 0 group aggregations and areas of Presence/Absence source data. Horse mackerel.

Figure 24: 0 group aggregations and areas of Presence/Absence source data. Horse mackerel

Figure 25: 0 group aggregation areas and Coull (1998) nursery areas. Sprat.

Figure 25: 0 group aggregation areas and Coull (1998) nursery areas. Sprat

Figure 26: Probability of presence of 0 group aggregations. Blue whiting.

Figure 26: Probability of presence of 0 group aggregations. Blue whiting

Figure 27: 0 group aggregations and areas of Presence/Absence source data. Blue whiting.

Figure 27: 0 group aggregations and areas of Presence/Absence source data. Blue whiting

Figure 28: 0 group aggregation areas and Coull (1998) nursery areas. Blue whiting.

Figure 28: 0 group aggregation areas and Coull (1998) nursery areas. Blue whiting

Figure 29: Probability of presence of 0 group aggregations. Plaice.

Figure 29: Probability of presence of 0 group aggregations. Plaice

Figure 30: 0 group aggregations and areas of Presence/Absence source data. Plaice.

Figure 30: 0 group aggregations and areas of Presence/Absence source data

Figure 31: 0 group aggregation areas and Coull (1998) nursery areas. Plaice.

Figure 31: 0 group aggregation areas and Coull (1998) nursery areas. Plaice

Figure 32: Probability of presence of 0 group aggregations. Sole.

Figure 32: Probability of presence of 0 group aggregations. Sole

Figure 33: 0 group aggregations and areas of Presence/Absence source data. Sole.

Figure 33: 0 group aggregations and areas of Presence/Absence source data. Sole

Figure 34: 0 group aggregation areas and Coull (1998) nursery areas. Sole.

Figure 34: 0 group aggregation areas and Coull (1998) nursery areas. Sole

Figure 35: Probability of 0 group presences. Hake.

Figure 35: Probability of 0 group presences. Hake

Figure 36: 0 group presence areas and Presence/Absence source data. Hake.

Figure 36: 0 group presences areas and Presence/Absence source data. Hake

Figure 37: Probability of 0 group presences. Anglerfish.

Figure 37: Probability of 0 group presences. Anglerfish

Figure 38: 0 group presence areas and Presence/Absence source data. Anglerfish

Figure 38: 0 group presence areas and Presence/Absence source data. Anglerfish

3.2 Herring Small Larvae Aggregation Areas

A set of three maps has been created for each of the models, MAXENT and Random Forest:

a) The first map shows the probability of presence of aggregations of small
(<10 mm or <11 mm) herring larvae; aggregations were determined as detailed in Section 2.1.2.

The first map also shows information about the performance of the model, evaluated by the AUC and kappa statistics, as explained in Section 2.3. A summary of the performance of every model can be seen in Table 8.

b) The second map shows areas with high density of small herring larvae, identified as the areas with a probability of presence above the value at which kappa is maximum - as detailed in Section 2.3.

This map also shows Presence and Absence source data.

c) The third map shows how the newly defined areas of small larvae aggregation for herring compare to the spawning areas defined in Coull et al. (1998).

As it has also been explained in Section 2.1.2, two separate and independent runs of the models were done for data east and west of the 4°W meridian.

Table 9

Evaluation of models performance: AUC (Area Under the Curve) and kappa statistics.

AUC Kappa
Value Performance Value Performance
MAXENT - East 0.763 ± 0.017 Good 0.132 ± 0.027 Poor
MAXENT - West 0.762 ± 0.015 Good 0.151 ± 0.027 Poor
RForest - East 0.877 ± 0.009 Good 0.297 ± 0.023 Poor
RForest - West 0.879 ± 0.014 Good 0.319 ± 0.044 Poor

Figure 39: Probability of presence of small larvae aggregations - MAXENT.

Figure 39: Probability of presence of small larvae aggregations - MAXENT

Figure 40: Small larvae aggregation area ( MAXENT) and Presence/Absence source data.

Figure 40: Small larvae aggregation area (MAXENT) and Presence/Absence source data

Figure 41: Small larvae aggregation areas ( MAXENT) and Coull spawning areas.

Figure 41: Small larvae aggregation areas (MAXENT) and Coull spawning areas

Figure 42: Probability of presence of small larvae aggregations - Random Forest.

Figure 42: Probability of presence of small larvae aggregations - Random Forest

Figure 43: Small larvae aggregation area (Random Forest) and Presence/Absence source data.

Figure 43: Small larvae aggregation area (Random Forest) and Presence/Absence source data

Figure 44: Small larvae aggregation areas (Random Forest) and Coull spawning areas.

Figure 44: Small larvae aggregation areas (Random Forest) and Coull spawning areas

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