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^
http://science.sciencemag.org/
Downloaded from