Science - USA (2018-12-21)

scientifically surveyed, only 24 (or 13%) had no
commercial trawling present, and in 10 of those
MPAs, elasmobranchs have been reported. These
untrawled MPAs had indeed higher average elas-
mobranch abundance as compared with those of
commercially trawled MPAs (fig. S8). Overall,
elasmobranch abundance decreased with in-

creasing trawling intensity both inside (fig. S9)

and outside MPAs (fig. S10).

After controlling for spatial autocorrelation

and potentially confounding effects of habitat

and climate, we found that commercial trawling

was the strongest predictor of elasmobranch rela-

tive abundance across the study area (P<0.001)

(Fig. 3A and table S5), with an average decrease

of 69% across the observed gradient of trawling

intensity (0 to 6.4 hours km−^2 ). Analyzing this

relationship over time, we detected no trend in

relative elasmobranch abundance in areas with

high trawling intensity but detected higher and

increasing abundance in areas with low trawling

Dureuilet al.,Science 362 , 1403–1407 (2018) 21 December 2018 2of4

0

0.5

1

Outside Inside

Co

mmerci

al traw

lin

g

0

5

10

15

20

25

30

35

40

45

Outside Inside

Re

sea

rch

cat

ch

p

er h

aul

36

40

44

48

52

56

60

−16 −12 −8 −4 0 4 8 12 −16 −12 −8 −4 0 4 8 12

Longitude Longitude

Latitude

0.01

0.1

1

10

100

250

0.01

0.1

0.5

1

1.5

2.4

AB

0.005

0.056

0.336

0.348

1.08

1.23

1.59

8.62

35

52

63

154

187

773

3289

4272

8995

12508

14176

20410

26050

70573

102759

171156

Ecological Sites of Special Interest

Nature Reserve UK

Regional Nature Reserve (Flemish Region)

Protected Dunes (Flemish Region)

Natural Monument

Biotope Protection Order

Site of national interest

Voluntary Reserve

Site of Special Scientific Interest (GB)

Conservatoire du littoral

National Hunting and Wildlife Reserve

Demonstration and Research Marine Protected Area

Ramsar Site, Wetland of International Importance

Marine Protected Area

Nature Reserve Germany

National Park

Baltic Sea Protected Area (HELCOM)

Marine Nature Park

Nature Conservation Act

Marine Conservation Zone

Nature Conservation Marine Protected Area

Special Protection Area (Birds Directive)

Site of Community Importance (Habitats Directive)

Marine Protected Area (OSPAR)

0 90000 180000

Area

C

012345

Trawling

D

012

Abundance

E

Fig. 1. Spatial distribution of marine protected areas, commercial
trawling, and elasmobranchs in the European Union.(A) Commercial
trawl fishing hours per 0.01° × 0.01° grid cell in 2017 (log 10 color scale).
Existing MPAs as of 2016 are outlined with black borders. (Inset)
Aggregate commercial trawling intensity (hours per square kilometer)
across MPAs versus unprotected areas. (B) Elasmobranchs scientific
survey abundance expressed as normalized multispecies catch per unit
effort per 0.25° × 0.25° grid cell (square-root transformed color scale).

Grid cells in purple were surveyed, but no elasmobranchs were

present. (Inset) The total elasmobranch research catch per haul inside

versus outside MPAs, with 95% confidence limits. (C)MPAarea

(square kilometers), (D) commercial trawling intensity per trawled area

(logehours per square kilometer trawled), and (E) elasmobranch abundance

index for each MPA type. The gray dotted line in (D) indicates the median

commercial trawling intensity in nonprotected areas for reference. No data

in (E) indicates MPA types that were not scientifically surveyed.

RESEARCH | REPORT

on December 20, 2018^

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