| Literature DB >> 19623248 |
Natalie C Ban1, Amanda C J Vincent.
Abstract
BACKGROUND: Marine populations have been declining at a worrying rate, due in large part to fishing pressures. The challenge is to secure a future for marine life while minimizing impacts on fishers and fishing communities. METHODS AND PRINCIPALEntities:
Mesh:
Year: 2009 PMID: 19623248 PMCID: PMC2707608 DOI: 10.1371/journal.pone.0006258
Source DB: PubMed Journal: PLoS One ISSN: 1932-6203 Impact factor: 3.240
Figure 1Decreases in areas fished resulting from reductions of catches for 13 commercial marine fisheries (British Columbia, Canada).
Each of 11 scenarios was repeated 10 times, with 100 runs of one million iterations each (11,000 runs). The result requiring the least area of each of the 10 repetitions per scenarios is graphed (i.e., there are 10 data points per scenario; some overlap closely and appear as one).
Figure 2Marine ecosections in British Columbia and selected permitted fishing area solutions.
The marine ecosections (a) are 1 = Dixon Entrance; 2 = Hecate Strait; 3 = Johnstone Strait; 4 = Juan de Fuca Strait; 5 = North Coast Fjords; 6 = Queen Charlotte Sound; 7 = Queen Charlotte Strait; 8 = Strait of Georgia; 9 = Subarctic Pacific; 10 = Transitional Pacific; 11 = Vancouver Island Shelf; 12 = Continental Slope. The selection frequency map (b) shows the importance of areas to commercial fisheries based pm the summed solution results from Marxan. The permitted fishing area solutions (in blue) are for a sample of the scenarios that minimize the area fished with the corresponding percent reduction in commercial fishing catches: (c) 5%, (d) 20%, (e) 40%.
Gap analysis by ecosection for the most spatially limited result for each scenario.
| Area of ecosection (ha * 1000) | % of area fished | Percent reduction in catches (italics), resulting in percent protected (plain, in %) | |||||||||||
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| Continental Slope | 3,330 | 53.8 | 55.3 | 60.0 | 64.8 | 74.5 | 78.6 | 79.2 | 84.5 | 88.5 | 91.9 | 89.6 | 97.2 |
| Dixon Entrance | 1,089 | 55.4 | 57.8 | 64.8 | 72.0 | 79.1 | 83.0 | 90.8 | 86.9 | 89.9 | 95.3 | 93.6 | 98.1 |
| Hecate Strait | 1,280 | 77.0 | 36.5 | 43.0 | 50.0 | 57.6 | 64.9 | 70.9 | 74.5 | 82.7 | 91.7 | 85.5 | 95.5 |
| Johnstone Strait | 239 | 98.0 | 11.4 | 19.2 | 24.1 | 46.3 | 58.1 | 65.1 | 98.0 | 73.0 | 81.7 | 81.8 | 96.1 |
| Juan de Fuca Strait | 150 | 90.8 | 15.5 | 27.0 | 67.4 | 56.7 | 74.6 | 72.8 | 69.5 | 96.6 | 100 | 97.7 | 100 |
| North Coast Fjords | 958 | 91.9 | 23.6 | 33.9 | 46.9 | 59.6 | 68.7 | 72.8 | 80.5 | 83.3 | 91.3 | 85.2 | 96.4 |
| Queen Charlotte Sound | 3,642 | 55.7 | 60.7 | 68.1 | 75.9 | 82.5 | 87.5 | 89.1 | 89.8 | 90.1 | 97.4 | 94.2 | 99.2 |
| Queen Charlotte Strait | 220 | 94.5 | 7.9 | 18.1 | 33.2 | 46.2 | 45.6 | 69.4 | 66.4 | 56.8 | 93.2 | 74.6 | 86.0 |
| Strait of Georgia | 815 | 94.8 | 7.9 | 63.0 | 14.6 | 27.3 | 31.2 | 51.7 | 50.7 | 64.5 | 79.4 | 77.8 | 92.7 |
| Subarctic Pacific | 17,098 | 0.3 | 99.8 | 99.9 | 99.9 | 99.9 | 99.9 | 100 | 99.6 | 100 | 100 | 100 | 100 |
| Transitional Pacific | 14,850 | 0.1 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| Vancouver Island Shelf | 1,670 | 89.2 | 17.8 | 24.4 | 30.9 | 42.2 | 56.3 | 66.8 | 70.7 | 76.4 | 87.9 | 75.5 | 93.8 |
Detailed analysis of the result of the 5% catch reduction scenario that produced the greatest area unfished, indicating ecosystem components that would be protected.
| Total area (ha) of each ecological feature | % outside permitted fishing areas | ||
| Depth | Shallow (0–20 m) | 743,853 | 40.6 |
| Photic (20–50 m) | 1,521,555 | 42.9 | |
| Mid-depth (50–200 m) | 60,400,258 | 94.3 | |
| Deep (200–1000 m) | 3,469,678 | 43.9 | |
| Abyssal (>1000 m) | 33,627,695 | 99.7 | |
| Temperature (summer at seabed bottom) | Warm (9–15°C) | 2,438,557 | 32.9 |
| Cool (<9°C) | 42,820,022 | 88.0 | |
| Slope | Flat (0–5%) | 40,556,889 | 87.2 |
| Sloping (5–20%) | 4,737,411 | 67.4 | |
| Steep (>20%) | 42,749 | 43.0 | |
| Current | High (>3 knots) | 212,713 | 39.0 |
| Low (<3 knots) | 45,162,974 | 85.3 | |
| Substrate | Mud | 2,295,529 | 27.6 |
| Sand | 4,852,577 | 47.7 | |
| Hard | 3,631,788 | 53.5 | |
| Exposure | High | 42,616,399 | 89.0 |
| Moderate | 1,287,192 | 17.4 | |
| Low | 1,470,964 | 30.4 | |
| Relief | High | 206,158 | 17.6 |
| Moderate | 20,839,047 | 93.9 | |
| Low | 43,040,993 | 87.7 | |
| Salinity (annual average at surface) | Mesohaline (5–18ppt) | 147,957 | 22.1 |
| Polyhaline (18–28 ppt) | 11,279,517 | 91.7 | |
| Euhaline (28–33 ppt) | 43,945,636 | 87.0 | |
| Stratification | Mixed | 4,931,996 | 36.8 |
| Weakly-mixed | 2,083,666 | 42.3 | |
| Stratified | 37,823,783 | 94.4 | |
| Kelp | 79,806 | 19.5 | |
| Eelgrass | 10,449 | 28.7 | |
| Clam | 18,978 | 22.5 | |
| Herring spawn | 99,737 | 22.3 | |
| Sponge reefs | 69,733 | 85.0 |
Actual catch reductions and estimated direct financial impact for each fishery under the scenario that (a) reduced overall catch by 2%, 5% and 10% and (b) produced the greatest area unfished at that level.
| Actual catch reduction (%) | Estimated direct impact (US$) | |||||
| Commercial fishery | 2% catch reduction scenario | 5% catch reduction scenario | 10% catch reduction scenario | 2% catch reduction scenario | 5% catch reduction scenario | 10% catch reduction scenario |
| Crab | 2.0 | 5.0 | 10.0 | 665,624 | 1,664,103 | 3,327,551 |
| Geoduck | 2.0 | 5.0 | 10.0 | 113,128 | 282,906 | 565,828 |
| Green urchin | 2.0 | 5.0 | 10.0 | 5,021 | 12,512 | 25,122 |
| Groundfish trawl | 2.0 | 5.0 | 10.0 | 470,332 | 1,175,818 | 2,351,668 |
| Krill | 1.9 | 4.7 | 9.9 | NA | NA | NA |
| Prawn | 2.0 | 5.0 | 10.0 | 234,238 | 585,538 | 1,171,154 |
| Red urchin | 2.0 | 5.0 | 10.0 | 186,231 | 465,469 | 932,242 |
| Sablefish longline | 1.2 | 1.5 | 3.4 | 35,061 | 42,496 | 95,713 |
| Sablefish trap | 2.0 | 5.0 | 10.0 | 266,145 | 665,345 | 1,330,782 |
| Schedule two | 2.0 | 5.0 | 10.0 | 19,455 | 48,632 | 97,280 |
| Sea cucumber | 2.0 | 4.7 | 10.0 | 35,661 | 83,147 | 178,338 |
| Shrimp trawl | 2.0 | 4.2 | 7.2 | 207,272 | 430,335 | 748,438 |
| ZN catch | 2.0 | 5.0 | 10.0 | 17,223 | 43,057 | 86,118 |
| Total | 2,255,391 | 5,499,359 | 10,910,233 | |||
Ex-vessel data obtained from the Sea Around Us online database (www.seaaroundus.org) [21]. We used mean annual prices from 2000 to 2004 in the reporting units of US$. At the time of writing the Canadian and US currencies were about par.
NA = ex-vessel data not available.
Proportion of annual commercial fisheries catches that fall within the permitted fishing area result of the 95% target scenario.
| Fishery | Annual data | Average | Standard deviation | Minimum | Maximum |
| Geoduck | 2002–2004 | 95.04% | 1.91% | 92.96% | 96.73% |
| Green urchin | 1998–2003 | 94.29% | 2.89% | 90.49% | 97.05% |
| Red urchin | 1997–2003 | 95.07% | 0.39% | 94.72% | 95.82% |
| Sea cucumber | 1997–2004 | 94.81% | 3.07% | 88.25% | 97.97% |