Scottish Marine and Freshwater Science Volume 3 Number 10: Scottish Scallop Stocks - Results of 2011 Assessments

This report presents the results of Scottish regional scallop stock assessments carried out by Marine Scotland Science (MSS) based on commercial catch-at-age and survey data up to and including 2010.


8. Figures

Figure 2.1.1: Scottish scallop assessment areas.

Figure 2.1.1: Scottish scallop assessment areas.

Figure 3.1.1: Total reported landings by assessment area (tonnes).

Figure 3.1.1: Total reported landings by assessment area (tonnes). The Irish Sea and West of Kintyre also have landings into countries other than Scotland (solid line: Scotland, dotted line: UK (non Scotland), dashed line: Isle of Man). Some UK (non Scotland) landings pre 2000 may have been taken elsewhere in Division VIIa ( i.e. out-with the Irish Sea assessment area). Note differences in scales of landings.

Figure 3.1.2: Spatial distribution of dredge caught scallop landings (tonnes) from Scottish scallop assessment areas into Scotland in 2010.

Figure 3.1.2: Spatial distribution of dredge caught scallop landings (tonnes) from Scottish scallop assessment areas into Scotland in 2010. Landings from statistical rectangle 40E4 are split into and east and west component.

Figure 3.1.3: Spatial distribution of dredge caught scallop landings (tonnes) from Scottish scallop assessment areas into ports outside Scotland in 2010.

Figure 3.1.3: Spatial distribution of dredge caught scallop landings (tonnes) from Scottish scallop assessment areas into ports outside Scotland in 2010.

Figure 3.1.4: Spatial distribution of dive caught scallop landings (tonnes) in 2010.

Figure 3.1.4: Spatial distribution of dive caught scallop landings (tonnes) in 2010.

Catch at age for West of Kintyre

Figure 3.2.1: West of Kintyre. Total catch-at-age numbers (in thousands).

Figure 3.2.1: West of Kintyre. Total catch-at-age numbers (in thousands).

Mean weights at age for West of Kintyre

Figure 3.2.2: West of Kintyre. Mean weights-at-age (kg) in total catch (also used for stock weights).

Figure 3.2.2: West of Kintyre. Mean weights-at-age (kg) in total catch (also used for stock weights).

Figure 3.2.3: West of Kintyre. Catch curves from commercial data (ages 3 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.2.3: West of Kintyre. Catch curves from commercial data (ages 3 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.2.4: West of Kintyre. Distribution of dredge survey catch rates (2000-2010).

Figure 3.2.4: West of Kintyre. Distribution of dredge survey catch rates (2000-2010).

Figure 3.2.4: West of Kintyre. Distribution of dredge survey catch rates (2000-2010).

Scallop Survey

Figure 3.2.5: West of Kintyre. Catch curves from survey data (ages 2 ‑ 10+) by cohort (year class).

Figure 3.2.5: West of Kintyre. Catch curves from survey data (ages 2 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.2.6: West of Kintyre. TSA stock summaries from the final TSA run. Catch and SSB are in terms of muscle weight (thousand tonnes) and recruitment (age 3) in millions. Catch figure shows both model estimates (red line) and input data (points).

Figure 3.2.6: West of Kintyre. TSA stock summaries from the final TSA run. Catch and SSB are in terms of muscle weight (thousand tonnes) and recruitment (age 3) in millions. Catch figure shows both model estimates (red line) and input data (points). Estimates are plotted with approximate 95 % confidence intervals.

Figure 3.2.7: West of Kintyre. Standardised catch prediction errors by age from the final TSA run.

Figure 3.2.7: West of Kintyre. Standardised catch prediction errors by age from the final TSA run.

Figure 3.2.8: West of Kintyre. Standardised survey prediction errors by age from the final TSA run.

Figure 3.2.8: West of Kintyre. Standardised survey prediction errors by age from the final TSA run.

Figure 3.2.9: West of Kintyre. Stock-recruit plot from the final TSA run.

Figure 3.2.9: West of Kintyre. Stock-recruit plot from the final TSA run. Recruitment (age 3) is in millions and SSB in thousand tonnes muscle weight. Values are labelled with year class.

Figure 3.2.10: West of Kintyre.

Figure 3.2.10: West of Kintyre. Estimates of catch, mean F 4-6, SSB and recruitment with 95 % confidence intervals (pale lines) from retrospective TSA runs. Catch and SSB are in thousand tonnes and recruitment (age 3) in millions. Blue line: data to 2010, maroon line: data to 2009 and red line: data to 2008.

Catch at age for North West

Figure 3.3.1: North West.

Figure 3.3.1: North West. Total catch-at-age numbers (in thousands).

Mean weights at age for North West

Figure 3.3.2: North West.

Figure 3.3.2: North West. Mean weights-at-age (kg) in total catch (also used for stock weights).

Commercial catch data

Figure 3.3.3: North West.

Figure 3.3.3: North West. Catch curves from commercial data (ages 3 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.3.4: North West.

Figure 3.3.4: North West.

Figure 3.3.4: North West. Distribution of dredge survey catch rates (2000-2010).

Scallop Survey

Figure 3.3.5: North West.

Figure 3.3.5: North West. Catch curves from survey data (ages 2 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.3.6: North West.

Figure 3.3.6: North West. TSA stock summaries from the final run. Catch and SSB are in terms of muscle weight (thousand tonnes) and recruitment (age 3) in millions. Catch figure shows both model estimates (red line) and input data (points). Estimates are plotted with approximate 95 % confidence intervals.

Figure 3.3.7: North West.

Figure 3.3.7: North West. Standardised catch prediction errors by age from the final TSA run.

Figure 3.3.8: North West.

Figure 3.3.8: North West. Standardised survey prediction errors by age from the final TSA run.

Figure 3.3.9: North West.

Figure 3.3.9: North West. Stock-recruit plot from the final TSA run. Recruitment is in millions (age 3) and SSB in thousand tonnes of muscle weight.. Values are labelled with year class.

Figure 3.3.10: North West.

Figure 3.3.10: North West. Estimates of Catch, Mean F 4-6, SSB and Recruitment with 95% confidence intervals (pale lines) from retrospective TSA runs. Catch and SSB are in thousand tonnes and recruitment in millions. Blue line: data to 2010, maroon line: data to 2009 and red line: data to 2008.

Catch at age for North East

Figure 3.6.1: North East.

Figure 3.6.1: North East. Total catch-at-age numbers (in thousands).

Mean weights at age for North East

Figure 3.6.2: North East.

Figure 3.6.2: North East. Mean weights-at-age (kg) in total catch (also used for stock weights).

Figure 3.6.3: North East.

Figure 3.6.3: North East. Catch curves from commercial data (ages 3 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Commercial catch data

Figure 3.6.4: North East.

Figure 3.6.4: North East.

Figure 3.6.4: North East. Distribution of dredge survey catch rates (2000-2010).

Scallop Survey

Figure 3.6.5: North East.

Figure 3.6.5: North East. Catch curves from survey data (ages 2 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.6.6: North East.

Figure 3.6.6: North East. TSA stock summaries from the final TSA run. Catch and SSB are in thousand tonnes and recruitment (age 3) in millions. Catch figure shows both model estimates (red line) and input data (points). Estimates are plotted with approximate 95 % confidence intervals.

Figure 3.6.7: North East.

Figure 3.6.7: North East. Standardised catch prediction errors by age from the final TSA run.

Figure 3.6.8: North East.

Figure 3.6.8: North East. Standardised survey prediction errors by age from the final TSA run.

Figure 3.6.9: North East.

Figure 3.6.9: North East. Stock-recruit plot from the final TSA run. Recruitment (age 3) is in millions and SSB in thousand tonnes of muscle weight. Values are labelled with year class.

Figure 3.6.10: North East.

Figure 3.6.10: North East. Estimates of Catch, Mean F 4-6, SSB and Recruitment with 95% confidence intervals (pale lines) from retrospective TSA runs. Catch and SSB are in thousand tonnes and recruitment in millions. Blue line: data to 2010, maroon line: data to 2009 and red line: data to 2008.

Catch at age for Shetland

Figure 3.7.1: Shetland.

Figure 3.7.1: Shetland. Total catch-at-age numbers (in thousands).

Mean weights at age for Shetland

Figure 3.7.2: Shetland.

Figure 3.7.2: Shetland. Mean weights-at-age (kg) in total catch (also used for stock weights).

Commercial catch data

Figure 3.7.3: Shetland.

Figure 3.7.3: Shetland. Catch curves from commercial data (ages 3 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.7.4: Shetland.

Figure 3.7.4: Shetland.

Figure 3.7.4: Shetland. Distribution of dredge survey catch rates (2000-2010).

Scallop Survey

Figure 3.7.5: Shetland.

Figure 3.7.5: Shetland. Catch curves from survey data (ages 2 ‑ 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.7.6: Shetland.

Figure 3.7.6: Shetland. TSA stock summaries from the final TSA run. Catch and SSB are in thousand tonnes and recruitment (age 3) in millions. Catch figure shows both model estimates (red line) and input data (points). Estimates are plotted with approximate 95 % confidence intervals.

Figure 3.7.7: Shetland.

Figure 3.7.7: Shetland. Standardised catch prediction errors by age from the final TSA run.

Figure 3.7.8: Shetland.

Figure 3.7.8: Shetland. Standardised survey prediction errors by age from the final TSA run.

Figure 3.7.9: Shetland.

Figure 3.7.9: Shetland. Stock-recruit plot from the final TSA run. Recruitment (age 3) is in millions and SSB in thousand tonnes. Values are labelled with year class.

Figure 3.7.10: Shetland.

Figure 3.7.10: Shetland. Estimates of Catch, Mean F 4-6, SSB and Recruitment with 95% confidence intervals (pale lines) from retrospective TSA runs. Catch and SSB are in thousand tonnes and recruitment (age 3) in millions. Blue line: data to 2010, maroon line: data to 2009 and red line: data to 2008.

Catch at age for East Coast

Figure 3.8.1: East Coast.

Figure 3.8.1: East Coast. Total catch-at-age numbers (in thousands).

Mean Weights at age for East Coast

Figure 3.8.2: East Coast.

Figure 3.8.2: East Coast. Mean weights-at-age (kg) in total catch (also used for stock weights).

Commercial catch data

Figure 3.8.3: East Coast.

Figure 3.8.3: East Coast. Catch curves from commercial data (ages 3 - 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.8.4: East Coast.

Figure 3.8.4: East Coast.

Figure 3.8.4: East Coast. Distribution of dredge survey catch rates (2000-2010).

Scallop Survey

Figure 3.8.5: East Coast.

Figure 3.8.5: East Coast. Catch curves from survey data (ages 2 - 10+) by cohort (year class). The bold line represents log catch number and for reference the average log catch curve is shown in grey.

Figure 3.8.6: East Coast.

Figure 3.8.6: East Coast. Stock summary (trends only): reported landings (muscle weight of catch in thousand tonnes), SSB and recruitment indices derived from the survey index (mean standardised) and mean standardised F proxy (ratio of catch to SSB). No survey in 1997.

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