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The deep-water coral Lophelia pertusa in Norwegian waters: distribution and fishery impacts - page 6 / 12

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Table 1. Overview of the contribution from the different sources of information

8

12

19

1

31

Damaged areas

4

10

51

65

Intact corals

6

7

27

1

41

Status unknown

6

11

32

49

Unknown

3

3

Source

Total number of fishermen

Fishermen " " Charts

Status of reefs

R1

R2

R3

R4

Sum

Directorate of Fisheries (dredge) IMR (trawl) Statoil (ROV and multibeam) Scientific literature (see Methods) IMR (ROV inspections)

Unknown Unknown Intact Different Damaged

areas

29

11

11

70

14

7

59

15

2

9

29 22 70 95 11

IMR (ROV inspections)

Intact corals

  • 18

4

22

Some fishermen informed about damaged areas as well as intact reefs in different regions

and are counted in several columns.The correct number of fishermen is 31. IMR: Institute of Marine Research). R1–R4 refer to the regions defined in Figure 1.

Table 2. ROV inspections on the Norwegian continental shelf and break in 1998–99 (see also Figure 1)

Locality

Date

Sørmannsneset " Aktivneset Korallneset Maurdjupet Iverryggen " " " "

16 May 98 " 26 April 99 27 April 99 " 17 May 99 " " " "

Depth (m)

345–260 370–225 350–270 305–205 280 199–170 180–170 200–191 203–195 259–231

Dist (km)

2.5 2.9 7.0 2.2 0.6 0.2 0.3 0.1 2.0

N

Start E

05

05

03

04

05

09

09

09

09

09

63

63

62

62

62

64

64

64

64

65

11.00

05.50

31.25

03.80

10.02

06.75

07.88

08.64

10.57

15.78

0 4 . 9 0 , 0 4 . 5 0 , 3 7 . 8 0 , 4 1 . 4 5 , 3 6 . 1 7 , 5 6 . 6 5 , 5 7 . 1 0 , 5 7 . 6 3 , 5 8 . 2 5 , 0 4 . 3 4 ,

E

05 09.60 05 07.50 03 34.00 04 03.75

09 06.73 09 07.95 09 09.00 09 10.71 09 17.37

64

64

64

65

N

Stop

6 3 0 3 . 7 0 , 6 3 0 3 . 2 0 , 6 2 3 4 . 2 5 , 6 2 4 0 . 2 5 ,

6 4 5 6 . 9 8 5 7 . 2 , 2 , 5 7 . 6 2 , 5 8 . 2 0 , 0 5 . 1 7 ,

The depth range covered, and the positions at start and stop. In the locality Iverryggen the distance between start and stop might be longer than given because the ROV did not follow a straigth course.

Region

Total area

Damaged area

Damaged area as %

R1 R2 R3 R4

222–237 590–702 715–875 0.5–1

30–40 176–242 356–456 <0.3

15–17 30–35 50–52 5

ural Lophelia reefs also seemed to be crushed and spread around (Fig. 6).

At Iverryggen damage due to passive gear was confirmed as well, as indicated by the presence of lost gillnets (Fig. 8). The nets and the anchor-ropes may sometimes severely disturb the corals by breaking down and tilting parts of the colonies. This impact is not uncommon in other coral grounds as well.

Table 3. Estimates of total area of corals and estimated damaged areas (km2)

R1–R4 refer to the regions defined in Figure 1.

Estimation of coral areas and damaged areas

Table 3 shows estimates of areas with corals in Nor- wegian waters. The range of estimates derived from the use of minimum and maximum widths (200 and 500 m, respectively) in the calculation of stretch areas between two points.

The four regions defined, R1-R4, have different sizes, the two northern regions (R1 and R2) being the largest and the two southern (R3 and R4) the smal- ler ones. The northern- and southernmost have fewest coral areas. Of R2 and R3 it is R3 that has the largest area of corals and because R3 is smaller than R2 it also has the highest density of corals. The percentage of

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