How wild is the ocean? Assessing the intensity of ... · PDF file02.04.2007 · patterns of human activities in the ocean exist (but see Lumb et al., 2004). Previous studies have focused

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS

Aquatic Conserv: Mar. Freshw. Ecosyst. 18: 55–85 (2008)

Published online 2 April 2007 in Wiley InterScience(www.interscience.wiley.com) DOI: 10.1002/aqc.816

How wild is the ocean? Assessing the intensity ofanthropogenic marine activities in British Columbia, Canada

NATALIE BANa,* and JACKIE ALDERb

aUniversity of British Columbia, UBC Fisheries Centre/Project Seahorse, Vancouver, British Columbia, CanadabUniversity of British Columbia, UBC Fisheries Centre/Sea Around Us Project, Vancouver, British Columbia, Canada

ABSTRACT

1. The intensity of marine activities in the exclusive economic zone (EEZ) of British Columbia,Canada, was quantified.2. Humans use the ocean for a multitude of purposes, many of which have a direct impact on

marine life and habitat. Yet such uses are seldom assessed in an integrated fashion.3. Using a GIS approach, spatial information for 39 marine activities was mapped, including

commercial and recreational fishing areas, transportation and infrastructure uses, and terrestrialactivities along the coast of British Columbia.4. A relative scale was used to rank both the impact of marine activities and the extent of stressors

beyond the location of occurrence. Limited information on the latter led to the application of threeranges of buffer distances to the data (0–1 km, 0–5 km, and 0–25 km).5. The most conservative estimate (41 km buffers) indicates at least 83% of the continental shelf

and slope of British Columbia is currently being used by humans. The largest buffer assumptionshows 98% of the continental shelf and slope being affected by stressors from anthropogenicactivities.6. This analysis provides a baseline for assessing future changes in the state of British Columbia’s

marine environment, and could assist in identifying areas of conservation potential.Copyright # 2007 John Wiley & Sons, Ltd.

Received 14 March 2006; Accepted 20 September 2006

KEY WORDS: human impact; fisheries; stressors; marine protected areas; British Columbia; conservation

planning; marine conservation; coastal zone management

INTRODUCTION

Most human activities in the ocean have a direct and/or indirect impact on marine life and habitat(McIntyre, 1995; Jackson et al., 2001). The oceans are fished for economic benefit, subsistence and

*Correspondence to: Natalie Ban, University of British Columbia, UBC Fisheries Centre/Project Seahorse, 2202 Main Mall,2nd Floor, Vancouver, BC V6T 1Z4, Canada. E-mail: [email protected]

Copyright # 2007 John Wiley & Sons, Ltd.

recreation (Botsford et al., 1997; Costanza, 1999; Cooke and Cowx, 2006). Oceans serve as a majortransportation network, coastal areas continue to have among the highest population densities, and peopleenjoy the ocean for pleasure and relaxation. All these pressures on the oceans are having an impact (Vincentand Hall, 1996; Roberts and Hawkins, 1999; Verity et al., 2002; Solan et al., 2004; Kappel, 2005). We areincreasingly fishing down trophic levels (Pauly et al., 1998, 2002, 2005; Watson et al., 2004), predatoryfishes have declined significantly (Myers and Worm, 2003, 2005; Devine et al., 2006) and pollution isprevalent (McIntyre, 1995; Siboni et al., 2004).

The effect humans are having on the ocean has been well documented. For example, more than 70% offisheries are fully exploited or overexploited (FAO, 2004). Overfishing has occurred worldwide for manycenturies (Jackson et al., 2001), resulting in cascading effects on the pelagic food web (Scheffer et al., 2005)and other structural and functional changes (Hutchings, 2000; Jackson et al., 2001; Myers and Worm, 2003;Solan et al., 2004; Bascompte et al., 2005; Scheffer et al., 2005). Certain fishing techniques, such as bottomtrawling, are known to damage benthic structures (Thrush et al., 1998; Watling and Norse, 1998; Collieet al., 2000; Thrush and Dayton, 2002; Ardron, 2005; Kaiser et al., 2005). Recreational fishing may havesimilar effects as commercial fishing (Coleman et al., 2004; Cooke and Cowx, 2006). Finfish aquaculture hascontributed to habitat destruction, the introduction of species and diseases, and further depletion of wildfish stocks (Auditor General of Canada, 2000; Milewski, 2000; Naylor et al., 2000, 2001, 2003; Krkoseket al., 2005), while shellfish aquaculture can enhance algal growth rates, reduce food supply for otherherbivores, and bias community composition towards fast-growing species (Jamieson et al., 2001;Broekhuizen et al., 2002; Gibbs, 2004). Shipping, cruise ships and recreational boating affect marine faunathrough noise (Richardson and Malme, 1995; United States General Accounting Office, 2000; Moore andClarke, 2002; Foote et al., 2004; Commoy et al., 2005), pollution and the introduction of non-native speciesin ballast water (United States Environmental Protection Agency, 2002; Hampton et al., 2003), and altershorelines and habitats through erosion and the water column through sedimentation (Stevens andEkermo, 2003). Infrastructure, such as ferry docks, marinas, anchorages, boat launches, docks, piers andmoorings, contributes to pollution (Wendt et al., 1996; Turner et al., 1997; Backhurst and Cole, 2000b;Nightingale and Simenstad, 2001; Stevens and Ekermo, 2003), noise (Nightingale and Simenstad, 2001;Foote et al., 2004), habitat damage (Backhurst and Cole, 2000a; Milazzo et al., 2004; Stamski, 2005), andreduces light levels (Macfarlane et al., 2000; Sanger and Holland, 2002). Land-based activities alsoimpact nearby coastal and marine areas. For example, the biggest source of marine oil pollution isurban and industrial runoff (Government of British Columbia, 2006), and fauna in marine environmentsclose to urban centres have elevated heavy metals in their tissues (Bolton et al., 2004). Mines as far awayas 40 km from the coast result in elevated levels of heavy metals in the coastal environment (Hines et al.,2000), and acid mine drainage is toxic to marine flora and fauna (Grout and Levings, 2001; Levingset al., 2004).

The impacts caused by human activities can be divided into three categories: physical, chemical andbiological change. Physical change comprises direct alterations to habitats, and includes damage fromfishing gear, dredging, etc. (Watling and Norse, 1998; Nightingale and Simenstad, 2001). Noise fromshipping and boating is also considered a physical change. Increased noise has been shown to causemarine mammals to change their feeding, diving and swimming habits (Croll et al., 2001; Foote et al.,2004). Chemical change includes the effects of pollution, such as introduction of nutrients and toxicmaterials (United States General Accounting Office, 2000; Costanzo et al., 2001; Je et al., 2004). Biologicalchange is effected through fishing, potentially resulting in trophic cascades (Pauly et al., 1998; Jacksonet al., 2001), and also includes the introduction of disease and exotic species (Naylor et al., 2001, 2003;Gibbs, 2004).

A first step in managing marine resources effectively is to understand the influence humans are having onthe ocean, which activities are having an impact, where those activities are taking place, and how far thestressors from those activities extend. Yet very few comprehensive analyses of the extent and spatial

N. BAN AND J. ALDER56

Copyright # 2007 John Wiley & Sons, Ltd. Aquatic Conserv: Mar. Freshw. Ecosyst. 18: 55–85 (2008)

DOI: 10.1002/aqc

patterns of human activities in the ocean exist (but see Lumb et al., 2004). Previous studies have focused onidentifying the impacts of activities such as fishing (Collie et al., 2000; Jackson et al., 2001; Cooke andCowx, 2006), mining (Levings et al., 2004), shipping (Stevens and Ekermo, 2003; Hong et al., 2005), andaquaculture (Milewski, 2000; Krkosek et al., 2005), but have rarely examined the collective contribution ofmultiple activities (but see Lumb et al., 2004).

Human impact is commonly mapped on land (Hannah et al., 1994; Sanderson et al., 2002; Foley et al.,2005), in ways that may be instructive in marine environments. On land, roads are routinely used as a proxyfor human impact } areas distant from roads are considered intact } and advances in remote sensing andGIS facilitate such analyses (e.g. Nelson and Hellerstein, 1997; Lee et al., 2003; Government of BritishColumbia, 2006). However, in marine environments it is more difficult to identify areas affected by humansbecause of the ephemeral and episodic nature of many activities. Also, while many of the human impacts onland are clearly visible from space (e.g. logging, industrial development, urban centres), marine habitatimpacts occur below the water, and are therefore not detectable using current remote sensing technology.

This paper explores the impact of human activities in the ocean, using the exclusive economic zone (EEZ)of British Columbia (BC) as a case study. The human use of the marine environment is mapped in order toidentify patterns and intensity of use, providing an approximation of possible damage to marine life andhabitats.

METHODS

A geographic information systems (GIS) approach was used for data analysis (ESRI, 2004, ArcGIS Version9.0). The Albers Equal Area projection (NAD83) was used throughout the analysis, because it holdsconstant the areas on the maps.

Spatial data for marine activities from 1992 to 2005 were collated, for a total of 39 data layers of humanuses affecting the ocean. Data layers include commercial and recreational fishing areas, transportation andinfrastructure uses, aquaculture, and land-based activities in the coastal area (see Table 1 for a complete listof datasets used). Data were obtained from federal and provincial government agencies; much of theinfrastructure data were provided by the Province of British Columbia through the Terrain ResourceInformation Management (TRIM) data. Only very few spatial data were available for the period prior to1992, and thus historical uses were not considered in this analysis. Spatial data were not available for allhuman uses (see Table 2 for missing or unavailable data).

Given that marine activities do not affect the marine environment equally, a measure of the impact ofmarine activities at the location of occurrence was incorporated. Ranking impacts can be contentious, asconflicting evidence can lead to differing interpretations of relative impact. Therefore an existingclassification method was sought, and one which ranks 27 out of the 39 uses mapped in this study wasapplied (Jamieson and Levings, 2001). This scheme uses a qualitative ranking of the direct and indirectimpact of human activities for British Columbia (high impact ¼ 10; least impact ¼ 0), developed throughfocus groups of regional experts representing habitat managers and field biologists (Jamieson and Levings,2001). Only the ‘severity and duration of impact’ values were applied; the ‘extent of impact’ categoryincluded in Jamieson and Levings (2001) was superfluous as the geographic extent of activities wereincluded in this analysis through spatial data. The median value of 0.3 for weighting indirect impacts wasused, for a maximum possible impact value was 13. The impact value was calculated using the formula:

impact ¼ directþ ð0:3*indirectÞ

Table 1 contains an explanation of all the impact values used.For most marine activities, little was known about the geographic extent of the impact beyond the

location of the activity. A table was compiled referencing the measured impacts of activities (Table 3).

ASSESSING INTENSITY OF ANTHROPOGENIC ACTIVITIES 57


DOI: 10.1002/aqc

Table1.Data

used,relativestressors

beyondthelocationofoccurrence,im

pact

factorandcalculation,andcategories

ofim

pact

Typeofdata

Sourceofdata

Stressor

beyond

locationof

occurrence

Severityanddurationof

impact

(0¼

least;

10¼

greatest)a

Impact¼

direct

þð0:3

bindirect)

How

theim

pact

valuewasderived

from

Jamiesonand

Levings(2001)

Category

of

impact

References

Direct

Indirect

Physical

change

Chem

ical

change

Biological

change

Baselineand

protected

areas

BC

coastline

Province

ofBC

N/A

Marine

ecoregions

Province

ofBC

N/A

Provincial

protected

area

designations

Province

ofBC

(ftp://ftp.gis.luco.

gov.bc.ca/pub/)

N/A

NationalParks

ParksCanada

N/A

Rockfish

conservation

areas

Fisheriesand

OceansCanada

(http://w

ww-

heb.pac.dfo-m

po.

gc.ca/m

aps/

them

esdata

e.htm

)

N/A

Marine

Protected

Areas

Fisheriesand

OceansCanada

(http://w

ww.pac.

dfo-m

po.gc.ca/

oceans/mpa/

Info

e.htm

)

N/A

Aquaculture

Finfish

aquaculture

Province

ofBC


gov.bc.ca/pub/

coastal/)

High

96

10.8

Severityand

duration

ofim

pact

habitatrating

||

|Auditor

Generalof

Canada,2000;

Milew

ski,

2000;

Nayloret

al.,2000;

Jamiesonand

Levings,2001;

Nayloret

al.,

2001;Naylor

etal.,2003;

Krkoseket

al.,2005

Shellfish

aquaculture

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.ca/

pub/coastal/)

Low

12

1.6

Severityand

duration

ofim

pact

habitatrating

||

Jamiesonet

al.,

2001;Jamieson

andLevings,

2001;

Broekhuizen

etal.,2002;

Gibbs,2004



DOI: 10.1002/aqc

Commercial

fisheries

Pauly

etal.,

1998;Thrush

etal.,1998;

Jacksonet

al.,

2001;Jamieson

andLevings,

2001

Bottom

trawling

Fisheriesand

OceansCanada

(DFO)1996to

2005groundfish

trawldata

(no.of

sets;nodata

ifless

than3distinct

vesselsfished

ina

grid)in

10km

by10km

grid

(None)

8(destructionof

substrate

structure

orstructural,

epibenthic

species)

4(sedim

ent

plume;

loss

ofhabitat

forother

species,bycatch)

9.2

Jamiesonand

Levings(2001),

averageof‘severity

andduration

ofim

pact

habitat’

and‘species’

ratings

||

Watlingand

Norse,

1998;

Collie

etal.,

2000;Thrush

and

Dayton,2002;

Ardron,2005;

Kaiser

etal.,

2005

Commercial

urchin

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.ca/

pub/coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact

habitat’and‘species’

ratings

||

Commercial

shrimp

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.

ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severity

andduration

ofim

pact

habitat’and

‘species’ratings

||

Commercial

seacucumber

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationof

impact

habitat’and

‘species’

ratings

||

Commercial

scallop

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact

habitat’and


||

Commercial

salm

ontroll

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact

habitat’and


||

Commercial

salm

onnet

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact

habitat’and


||

continued

over



DOI: 10.1002/aqc

Commercial

groundfish

(other

than

bottom

trawling)

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.ca/

pub/coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact


ratings

||

Commercial

squid

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.ca/

pub/coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact

habitat’and


||

Commercial

prawn

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.

ca/pub/coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact


ratings

||

Commercial

octopus

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact


ratings

||

Commercial

herring

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.

ca/pub/coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact


ratings

||

Commercial

herringroe

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.ca/

pub/coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationofim

pact


ratings

||

Commercial

gooseneck

barnacle

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.ca/

pub/coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationof

impact

habitat’

and‘species’

ratings

||

Commercial

crab

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationof

impact

habitat’

and‘species’

ratings

||

Table1.continued

Typeofdata

Sourceofdata

Stressor

beyond

locationof

occurrence


impact

(0¼

least;

10¼

greatest)a

Impact¼

direct

þð0:3bindirect)

How

theim

pact

valuewasderived

from

Jamiesonand

Levings(2001)

Category

of

impact

References

Direct

Indirect

Physical

change

Chem

ical

change

Biological

change



DOI: 10.1002/aqc

Commercial

geoduck

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

4(somedestruction

ofstructural,

epibenthic

species)

3(loss

ofhabitat

forother

species,

bycatch)

4.9

Averageof

‘severityand

durationof

impact

habitat’

and‘species’

ratings

||

Recreational

fisheriesb

Coleman

etal.,2004;

Cookeand

Cowx,2006

Recreational

squid

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

32(bycatch)

3.6

Lessthan

commercialfishing

because

presumably

alower

volumeis

extracted

||

Recreational

scallop

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

32(bycatch)

3.6

Lessthan

commercial

fishingbecause

presumably

a

lower

volume

isextracted

||

Recreational

prawn

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

32(bycatch)

3.6

Lessthan

commercialfishing

because

presumably

alower

volume

isextracted

||

Recreational

groundfish

Province

ofBC


gov.bc.ca/pub/

coastal/)

(None)

32(bycatch)

3.6

Lessthan

commercialfishing

because

presumably

alower

volumeis

extracted

||

Recreational

crabfishing

areas

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.

ca/pub/coastal/)

(None)

32(bycatch)

3.6

Lessthan

commercial

fishingbecause

presumably

a

lower

volume

isextracted

||

Recreational

fish

(not

species-

specific)

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.

ca/pub/coastal/)

(None)

32(bycatch)

3.6

Lessthan

commercialfishing

because

presumably

alower

volumeis

extracted

||

continued

over



DOI: 10.1002/aqc

Transportationand

infrastructure

Shippinglaneb

Coast

Guard

Medium

5(pollution,noise)

15.3

Higher

impact

thancommercial

fishingbecause

of

theconcentration

ofshipsusingthe

sameroute,but

causesless

habitat

destructionthan

bottom

trawling

orpermanent

structuressuch

as

ferrydocks

||

Moore

and

Clarke,

2002;

Hamptonet

al.,

2003

Cruiseship

routesb

Oilandgas

commission

website

Medium

5(noise,

discharge

ofeffl

uent)

25.6

Sameas

shippinglane,

buthigher

indirectim

pact

due

toblack

and

greywater

discharges

||

United

States

General

Accounting

Office,

2000;Commoy

etal.,2005

Anchorages

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.

ca/pub/coastal/)

Low

12(fishingandlitter)1.6

Severityand

durationof

impact

habitat

rating

||

Backhurstand

Cole,2000b;

Jamiesonand

Levings,2001;

Milazzoet

al.,

2004

Boatlaunches

bProvince

ofBC


gov.bc.ca/pub/

coastal/)

Medium-low

13(noise,

litter,

spills)

1.9

Considered

same

asanchorages,but

higher

indirect

impact

because

of

thepermanent

structures

||

Turner

etal.,

1997

Disposalsites

Province

ofBC


gov.bc.ca/pub/

coastal/)

High

10

4(possible

toxins,

leaching)

11.2

Severityand

durationof

impact

habitat

rating

|Jamiesonand

Levings,

2001;Savage,

2005

Moorageb

Province

ofBC

(ftp://ftp.gis.

luco.gov.bc.ca/

pub/coastal/)

Low

12(fishingand

litter)

1.6

Considered

same

asanchorages

||

Nightingale

and

Sim

enstad,

2001

Table1.continued

Typeofdata

Sourceofdata

Stressor

beyond

locationof

occurrence


impact

(0¼

least;

10¼

greatest)a

Impact¼

direct

þð0:3

bindirect)

How

theim

pact

valuewasderived

from

Jamiesonand

Levings(2001)

Category

of

impact

References

Direct

Indirect

Physical

change

Chem

ical

change

Biological

change



DOI: 10.1002/aqc

Ferry

dock

bTRIM

}Province

ofBC

Medium

8(destructionof

habitat,alteration

ofcurrents)

4(litter,toxins)

9.2

Lesssevere

(�2points)than

‘loadingareasand

term

inals’asonly

people

are

loaded

||

Nightingale

andSim

enstad,

2001;Stevens

andEkermo,

2003

Marinab

TRIM

}Province

ofBC

Medium

8(destructionof

habitat)

4(litter,toxins)

9.2

Lesssevere

(�2points)than

‘loadingareas

andterm

inals’

asonly

people

are

loaded

||

Turner

etal.,

1997;Nightingale

andSim

enstad,

2001

Ferry

route

bTRIM

}Province

ofBC

Medium-low

5(noise)

15.3

Sameas

shippinglane

||

Stevensand

Ekermo,2003

Docksb

TRIM

}Province

ofBC

Low

13(litter,fishing)

1.9

Considered

same

asanchorages,but

higher

indirect

impact

because

of

thepermanent

structures

||

Wendtet

al.,

1996;Macfarlane

etal.,2000;

Nightingale

and

Sim

enstad,2001

Pierb

TRIM

}Province

ofBC

Low

13(litter,fishing,

noise)

1.9

Considered

same

asanchorages,but

higher

indirect

impact

because

of

thepermanent

structures

||

Macfarlaneet

al.,

2000;Nightingale

andSim

enstad,

2001

Terrestrialuses

Terrestrial

Mining

TRIM

}Province

ofBC

Medium-low

03(w

asteand

chem

ical

dispersion,

sedim

entplume)

0.9

Someindirect

impact

due

topollution,metals,

acidrock

drainage

|Hines

etal.,

2000;Jamieson

andLevings,2001;

Levingset

al.,

2004

Built-upareab

TRIM

}Province

ofBC

Medium-high

2(increased

sedim

entation

discharge,

disturbance

of

naturalvegetation)

2(disturbance

ofestuarine

functions,removal

ofdetritalsources)

2.6

Somedirectim

pact

dueto

seaside

structures,

indirect

impact

dueto

urban

runoff

||

Nightingale

and

Sim

enstad,2001;

Kennish,2002;

Boltonet

al.,

2004

Industry

bProvince

ofBC


gov.bc.ca/pub/

coastal/)

High

87(possible

toxins)

10.1

Basedonan

averageof

‘industrialoutfall’,

‘groinsand

breakwaters’,

‘logbooming’,and

‘dredging’

||

Colodey

and

Wells,1992;

Khan,1997;

Roberts

etal.,

1998;Bolton

etal.,2004

Lighthouse

bTRIM

}Province

ofBC

Low

01

0.3

Someindirect

impact

due

tostructure

andhumanpresence

|Stamski,2005

aBasedonim

pact

weightingschem

edevised

byJamiesonandLevings(2001).

bActivitiesnotweightedbyJamiesonandLevings(2001).



DOI: 10.1002/aqc

Observed impacts vary by an order of magnitude in many cases, and therefore assumptions about theextent of the impact were applied to each data layer. These are termed stressors, as the impact on speciesand habitats is inferred. First, the assumption was that the stressors resulting from activities are localized,and a uniform 1-km buffer around point and line data was applied (Figure 1). Second, a medium extent ofstressors beyond the site of occurrence was assumed, with buffers out to a maximum of 5 km. Third, alarger extent of stressors was assumed, and buffers were assigned out to a maximum of 25 km. To apply thelast two assumptions, a qualitative ranking of high to low to rate the extent of stressors beyond the site ofoccurrence was devised based on a review of the literature (Table 3). Diminishing buffers were then assignedbased on the assumptions above, using the multiple buffer option with 1-km increments for the mediumbuffers, and 5 km increments for the large buffer assumption (Figure 2). Each marine use and its associatedbuffers was mapped on a raster (1 km2 grid), and then the impact of each activity was multiplied by itsrelative weighting (stressors) and the appropriate buffer distance (Figure 2). Where activities overlap in a

Table 2. Incomplete and missing data

Type of data Status of data Comments

Additional recreational fisheries Missing Limited spatial information on recreationalfishing areas is currently collected throughcreel surveys, and data on some targetedrecreational fisheries, such as salmon, ismissing from the spatial data files

Additional terrestrial: clear cuts,agriculture

Proprietary This kind of information could also beincorporated into a non-point-source pollutiondatabase

Commercial marine tourism: wildlifeviewing, sports fishing, diving

Missing Some recreational fishing areas are currentlyincluded, but sports fishing lodges are not.Other commercial tourism operations shouldalso be considered

Non-commercial marine tourism areas:pleasure boating

Missing

Invasive species Missing Problem areas for invasive species would helpidentify marine areas under stress

Non-point source pollution MissingAboriginal fisheries Missing/proprietaryShipping routes Missing Aside from the designated shipping lane in

Juan de Fuca Strait and Strait of Georgia, wewere unable to find data on routes used byshipping/tanker traffic

Climate change Missing Climate change, such as rising temperatures inthe ocean, has a ubiquitous impact. Yet theremay be areas that are seeing more changesthan average

Acidification Missing Acidification of the ocean is also a ubiquitousimpact. We do not know whether anyinformation exists for acidification in BritishColumbia

Historical impacts MissingNatural disturbance regimes MissingVulnerable and sensitive habitats MissingRisk of impact from activities MissingFuture developments and their potentialimpacts

Missing



DOI: 10.1002/aqc

Table3.Im

pact

beyondlocationofoccurrence

from

theliterature

Impact

beyondsite

Typeofdata

Typeofim

pact

Maxim

um

distance

of

observed

impact

Locationofstudy

References

High

Finfish

aquaculture

Transm

ittance

offurunculosis

24km

Puget

Sound

Quotedin

EVS

Environment

Consultants,2000,

Sea

lice

infectionsexceeded

ambient

levels

30km

British

Columbia

Krkoseket

al.,2005

Secondgenerationoflice

thatre-

infected

juvenilesalm

onexceeded

ambientlevels

75km

British

Columbia

Krkoseket

al.,2005

Escaped

Atlanticsalm

on

100sofkm

British

Columbia

Nayloret

al.,2001

Deadzonecreatedbyaccumulated

organic

matter

100to

500feet

British

Columbia

Quotedin

Nayloret

al.,

2003

Disposalsites

Sew

age-derived

nitrogen

tracedto

24km

from

outfall;sewageinfluence

most

pronouncedwithin

10km

10–24km

Baltic

Sea

Savage,

2005

Industry

Trace

metalcontaminants

found

�50km

distantfrom

Vancouver

harbour

�50km

British

Columbia

Boltonet

al.,2004

Structuralchanges

inbenthic

communitiesalongapresumed

pollutiongradient

�20km

British

Columbia

Jeet

al.,2004

Tracesofbark,fibre

andwoodchips

observed

12km

upcurrentfrom

apulp

andpaper

mill

12km

New

foundland

Khan,1997

Medium–high

Built-uparea

Structuralchanges

inbenthic

communitiesalongapresumed

pollutiongradient

�20km

British

Columbia

Jeet

al.,2004

Medium

Shippinglane

Responsesoffeedinghumpback

whales

tovessels

2–4km

British

Columbia

and

Alaska

RichardsonandMalm

e,1995

Illegaldumpingofoilywastes

80km

California

Hamptonet

al.,2003

Boatnoisecould

impaircommunication

betweenkillerwhalesover

arangeof

1–14km

1–14km

WashingtonandBritish

Columbia

Foote

etal.,2004

Cruiseship

routes

Volumeofgreywaterplumewith

detectable

levelsoftracerdye

6–45billionlitres

Florida

United

States

Environmental

ProtectionAgency,2002

Boatnoisecould

impaircommunication


arangeof

1–14km

1–14km


Columbia

Foote

etal.,2004

Marina

Dredgingformarinadevelopmentand

vesselnavigation,waterquality

issues

creatingconditionsfordinoflagellate

blooms

Atleast

extentofthe

marinaandvessel

channels

Washington

Nightingale

and

Sim

enstad,2001

Sweden

continued

over



DOI: 10.1002/aqc

Table3.continued

Impact

beyondsite

Typeofdata

Typeofim

pact

Maxim

um

distance

of

observed

impact

Locationofstudy

References

Sedim

entationanderosiondueto

ship

traffic

Erosionareasrepresent

56%

ofthetotal

1149000m

2mapped

StevensandEkermo,

2003

Ferry

dock

Increasedheavymetalcontamination,

differencesin

biologicalcommunities

andsettlementrates

1.4km

New

Zealand

Turner

etal.,1997

Medium–low

Ferry

route

Boatnoisecould

impaircommunication


arangeof

1–14km

1–14km


Columbia

Foote

etal.,2004

Duringconstruction,pile-drivingnoise

would

beheard

bysalm

onidswithin

aradiusofatleast

600m

from

thenoise

600m

Washington

Nightingale

and

Sim

enstad,2001

Boatlaunches

Increasedheavymetalcontamination,

differencesin

biologicalcommunities

andsettlementrates

1.4km

New

Zealand

Turner

etal.,1997

TerrestrialMining

Increasedlevelsofmercury

40km

from

abandoned

mercury

mine

40km

GulfofTrieste,Slovenia

andItaly

Hines

etal.,2000

Acidminedrainagehadadeleterious

effectonmusselsatleast

2.1km

north

and1.7km

south

ofthemine

Atleast

2.1km

British

Columbia

GroutandLevings,

2001

Low

Shellfish

aquaculture

Verylittle

quantified

inform

ationon

impactsbeyondshellfish

farm

sis

available,butseeBroekhuizen

etal.

(2002)foranoverview

Broekhuizen

etal.,2002

Introductionofexoticspecies

100sofkm

British

Columbia

Nayloret

al.,2001

Moorage


would

beheard

bysalm

onidswithin

aradiusofatleast

600m

from

thenoise

600m

Washington

Nightingale

and

Sim

enstad,2001;

StevensandEkermo,

2003

Anchorages

Anchordamageto

benthos

Scale

ofwhole

embayments

New

Zealand

BackhurstandCole,

2000a

Docks

Shadingfrom

theaveragedock

adversely

affects

87m

2marshgrass

87m

2South

Carolina

Sanger

andHolland,

2002

Lightlevelsreduced2–4ordersof

magnitude

2400feet

Seattle

Macfarlaneet

al.,2000;

Nightingale

and

Sim

enstad,2001

Pier


would

beheard

bysalm

onidswithin

aradiusofatleast

600m

from

thenoise

600m

Washington

Nightingale

and

Sim

enstad,2001

Lighthouse

Physicalhabitatalterationdueto

structuresanderosioncontrol

Unknown

California

Stamski,2005



DOI: 10.1002/aqc

grid cell, the values were added. Because of the variability in the fishing polygons, buffers were not used forfishing areas. The bottom trawling data were at a coarse scale summarized in a 10 km by 10 km grid, suchthat buffering these data could exaggerate the impact of this activity. The polygon data for the otherfisheries were of unknown completeness and accuracy, so were also handled without buffers.

A visual report of the pattern of use can help identify the stressors of human activities in the ocean. Threecomposite maps overlaying all activities were created, one for each of the above assumptions: a small bufferwith 1 km around line and point data, a medium buffer with a maximum buffer distance of 5 km foractivities with a high rating for the extent of stressors beyond the location of occurrence, and a large bufferwith a maximum buffer distance of 25 km for activities with a high rating for the extent of stressors beyondthe location of occurrence.

Two metrics were applied to gauge the extent of stressors of different types of activities. First the stressorvalue of each occurrence of an activity in a raster cell was added, then averaged over all available rastercells. This gives an indication of the highest average stressors. Second, the total number of raster cells wherean activity occurs was tabulated. This provides a measure of the extent of activities. Both of these metricswere calculated for each of the three buffer assumptions.

The marine areas currently covered by protected area designations were calculated to gauge existingprotection. The following designations were included in the calculation: Oceans Act Marine ProtectedAreas, National Parks, Rockfish Conservation Areas, provincial Protected Areas, Parks, Marine Parks,and Ecological Reserves. The BC marine ecological classification system was used to divide the marine areainto the offshore and continental shelf and slope regions (Zacharias and Howes, 1998; Zacharias et al.,1998). The Inner Pacific Shelf, Outer Pacific Shelf and Georgia Basin ecoregions comprise the continentalshelf and slope. The Subarctic and Transition Pacific ecoregions comprise the offshore region.

Boat launches

Finfish farms

km

Stressor value00 - 22-13

km

km

km

km

km

0 105 0 105 0 105

0 105

0 105

0 1050 105

km

(Symbols exagerated)

(Symbols exagerated)

(a) (b) (c)

(d)

(a) (b) (c)

Figure 1. Schematic of the methodology used to generate the small buffer (1 km) data layers and analysis, highlighting two activities inone part of British Columbia. (Additional activities take place in this particular part of BC). (a) The activities are mapped. (b) 1 kmbuffers are added to mapped activities (see Table 1). (c) The maps are converted to a 1 km2 raster grid, assigning the stressor valueassociated with each activity (Table 1). (d) The stressor values for all layers are added. This figure is available in colour online at

www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

Bo

at la

un

ches

Fin

fish

farm

s

010

5km

010

5km

(Sym

bo

ls e

xag

erat

ed)

(Sym

bo

ls e

xag

erat

ed)

010

5km

km

Str

esso

rva

lue 0 1.9

3.8

010

5km

01

km

Str

esso

rva

lue

10.8

21.6

32.4

43.2

54

010

5km

010

5km

km

IStr

esso

rva

lue

1-12

12-2

525

-36

36-4

747

-58

(a)

(a)

(b)

(b)

(c)

(c)

(d)

(d)

(e)

201

2

010

5

Figure

2.Schem

aticofthemethodologyusedto

generate

themedium

buffer

(upto

5km)data

layersandanalysis.(a)Theactivitiesare

mapped.(b)Buffersare

added

in1km

increm

ents

(upto

fivebuffers)

basedontheassigned

relativestressorbeyondthelocationofoccurrence

(asoutlined

inTable1).Activitieswithahighratingare

given

five1km

buffers,activitieswithamedium-highratingare

assigned

fourbuffers,etc.(c)Thestressorvalues

are

assigned

basedontheim

pact

valueassociatedwith

each

activity(Table1).Toassignthestressorvalue,theinnermostbuffer

multiplies

theim

pact

valuebythenumber

ofrings(n).Thenextbuffer

iscalculatedastheim

pact

valuetimes

thenumber

ofbuffersminusone,thenextbuffer

istheim

pactvaluetimes

thenumber

ofbuffersminustw

o,etc.Thiscreateddecreasingbuffer

values,withthe

innermostbuffer

havingthehigheststressorvalue.(d)Themapsare

convertedto

a1km

2raster

grid.(e)Allthelayersare

added.Thesamemethodologywasusedforthe

largebuffers(upto

25km),using5km

buffersinsteadofthe1km

buffersdescribed

above.

This

figure

isavailable

incolouronlineatwww.interscience.wiley.com/

journal/aqc



DOI: 10.1002/aqc

RESULTS

The continental shelf and slope of BC is being used extensively by humans (Table 4, Figures 3–8).Examining the map showing the number of overlapping activities with small buffers (1 km), 83% of thecontinental shelf and slope is affected by stressors from human activities (Figure 3). Under this bufferassumption, fishing activities appear most prominently (Figure 9). With buffers up to 5 km, the resultingmap does not appear very different (Figure 4), with 85% of the continental shelf and slope affected bystressors. Once buffers were extended to 25 km, however, the number of activities that overlapped increasedsubstantially in inshore coastal areas, 15% of the area used having more than nine overlapping activities(Figure 5). Under this assumption, 98% of the continental shelf and slope lay in areas with stressors fromhuman activities.

Accounting for the impact of activities by mapping predicted stressors, much of the continental shelf andslope region appears more affected than depicted by overlapping activities (Figures 6–8 for the small,medium, and large buffer assumptions). As with the small and medium buffer maps showing the number ofoverlapping activities (Figures 3 and 4), the small and medium buffer maps depicting stressors are similar toeach other (Figures 6 and 7). The large buffer map (Figure 8) highlights most coastal areas as having highrelative values of stressors.

The marine activity with the highest stressor value when averaged over all raster cells is commercialbottom trawling for both the small buffer assumption (Figure 9), and the medium buffer assumption(Figure 10). Assuming stressors extend up to 25 km beyond the sites of occurrence, however, indicated thatindustry exceeded bottom trawling as the activity with the highest average raster cell value (Figure 11). Theindustry data were used as categorized by the Province of British Columbia (Table 1), and includes loggingoperations (e.g. log booms, logging camps, log dumps), pulp and paper mills, industrial yards, oil tanks,conveyors, buildings, fish processing facilities and shipyards.

The category of marine activity in BC with the largest spatial extent was commercial fishing under boththe small and medium buffer assumptions given stressors (Figure 12) and the area used (Figure 13).Accounting for stressors under the large buffer assumption, the transportation and infrastructure categoryand terrestrial use category exceed the stressors resulting from commercial fishing (Figure 12). Recreationalfishing has the lowest stressor value under the medium and large buffer assumptions.

Very little of BC’s marine environment is currently protected (Table 5). BC’s EEZ has 1.47% of watersprotected, while the continental shelf and slope has a proportionally higher protection at 4.69%.

DISCUSSION

Intensity of use

The continental shelf and slope of British Columbia is used intensively by humans. Even under the mostconservative assumption about the extent of stressors resulting from human activities, a greater proportion

Table 4. Area affected by anthropogenic stressors

Buffer assumptions Area of EEZaffected byanthropogenicstressors (ha)

Percentage of EEZaffected byanthropogenicstressors

Area of continentalshelf and slope affectedby anthropogenicstressors (ha)

Percentage of continentalshelf and slope affectedby anthropogenicstressors

Small (0–1 km) buffer 12 596 412 27.78% 11 157 972 83.30%Medium (0–5 km) buffer 13 371 569 29.49% 11 431 612 85.34%Large (0–25 km) buffer 14 598 777 32.20% 13 094 191 97.75%



DOI: 10.1002/aqc

of BC’s continental shelf and slope is affected than the adjacent coastal terrestrial area, where 45.9% of thecoast and mountains ecoprovince is considered intact (Government of Canada, Province of BritishColumbia, 1998). The data used in this analysis indicate that the deep ocean beyond the continental shelfand slope remains little used, yet globally an increase in deep-sea fishing has been observed (Roberts, 2002).With such extensive use of the continental shelf and slope, very little if any of BC’s marine environment isuntouched.

Bottom trawling has been documented repeatedly as a destructive form of fishing (Watling and Norse,1998; Collie et al., 2000; Fossa et al., 2002; Ardron, 2005). In this analysis, bottom trawling has the highestaverage stressor value. However, this may be influenced by how this particular data layer is summarized.

Figure 3. Number of overlapping activities, applying the small buffer (1 km buffer) assumption. The number of activities in each 1 km2

grid cell is shown. The area inshore of the solid line is the continental slope and shelf. This figure is available in colour online atwww.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

Groundfish bottom trawling areas from 1996 to 2005 were obtained as documented in logbooks,summarized in 10 km by 10 km grid cells from the federal department Fisheries and Oceans Canada (DFO).Each such cell shows groundfish trawling activity when three or more distinct vessels trawled in that cell.Thus areas that do not show trawling may be trawled by one or two vessels, and it should not be inferredthat all ground within the trawled cells has been towed. More accurate bottom trawling data that do notexclude data would be very valuable.

Recreational fishing is probably much more extensive than available data show. Recreational fishing is apopular activity in BC. For example, in 2001 55% of the reported catch of chinook salmon was caught inthe tidal recreational fishery (FAO, 2001). A recent review of global recreational and commercial fisheries

Figure 4. Number of overlapping activities, applying the medium buffer (up to 5 km buffer) assumption. The number of activities ineach 1 km2 grid cell is shown. The area inshore of the solid line is the continental slope and shelf. This figure is available in colour

online at www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

suggests that the two types of fisheries may have similar impacts (Cooke and Cowx, 2006). Yet governmentcreel surveys are not designed to collect spatial data on recreational fishing (Fisheries and Oceans Canada,2006). Incorporating questions about the spatial distribution of fishing into creel surveys would greatlyimprove the information on recreational fishing. It may therefore be dangerous to dismiss recreationalfishing as an insignificant source of impact based on our results.

Protection of the marine environment

Very little of the marine environment in BC is protected, even though marine protected areas have been asubject of Canadian government policy development since the 1960s (Government of Canada, Province ofBritish Columbia, 1998). Marine protected areas can eliminate or reduce the direct impact of human

Figure 5. Number of overlapping activities, applying the large buffer (up to 25 km buffer) assumption. The number of activities in each1 km2 grid cell is shown. The area inshore of the solid line is the continental slope and shelf. This figure is available in colour online at

www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

activities on the ocean. British Columbia has several protected area designations that have previously beenconsidered as marine protected areas (Zacharias and Howes, 1998). Fisheries and Oceans Canada candesignate Marine Protected Areas under the Oceans Act, where the level of protection varies. NationalParks, designated under the National Parks Act may include a marine component, although the level ofprotection varies. Parks Canada can designate National Marine Conservation Areas under the NationalMarine Conservation Areas Act, which are meant to be zoned to allow various levels of use and mustinclude a no-take component. Environment Canada can establish marine wildlife areas, aimed primarily atprotecting seabird foraging areas. Fisheries and Oceans Canada has been designating Rockfish

Figure 6. Stressors resulting from human activities, applying the small buffer assumption (1 km). The area inshore of the solid line isthe continental slope and shelf. This figure is available in colour online at www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

Conservation Areas aimed to reduce the decline of inshore rockfish species. Activities unlikely to harmrockfish are permitted. Provincial Protected Areas, Marine Parks, and Ecological Reserves in the marineenvironment similarly vary in the level of protection.

The total area protected has changed little since a previous analysis in 1997 (Zacharias and Howes, 1998;Government of British Columbia, 2006). In total, all marine areas designated for conservation orprotection purposes combined cover 1.5% of British Columbia’s marine environment (Table 5). However,most of these areas were designated for terrestrial purposes, with boundaries extending into the marineenvironment without necessarily providing comprehensive marine protection (Jamieson and Levings,

Figure 7. Stressors resulting from human activities, applying the medium buffer assumption (up to 5 km). The area inshore of the solidline is the continental slope and shelf. This figure is available in colour online at www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

2001). Rockfish Conservation Areas currently cover 0.9% of British Columbia’s EEZ. These areas were setup to protect inshore rockfish under the inshore rockfish conservation strategy (Fisheries and OceansCanada, 2002), with the eventual goal of protecting about 20% of inshore rockfish habitat. One MarineProtected Area (Endeavour Hydrothermal Vents) covers 0.2% of BC’s marine area. No areas currentlyexist under the National Marine Conservation Area or Marine Wildlife Area designations. Given that avery large percentage of BC’s marine environment is already exposed to human activity, the need to providemore protection is urgent. The results from this analysis could be integrated as a cost layer into reserveselection tools (for such an approach in BC, see Ardron (2003)) to identify suitable conservation areas thatare predicted to be relatively less impacted.

Canada’s Oceans Strategy, led by Fisheries and Oceans Canada, is meant to provide an integratedapproach to ocean management, coordinate policies and programmes across governments, and generate a

Figure 8. Stressors resulting from human activities, applying the large buffer assumption (up to 25 km). The area inshore of the solidline is the continental slope and shelf. This figure is available in colour online at www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Comm

ercia

l pra

wn

Comm

ercia

l urc

hin

Recre

ation

al cr

ab

Comm

ercia

l her

ring

roe

Ferry

rout

es

Cruise

ship

rout

es

Comm

ercia

l cra

b

Comm

ercia

l shr

imp

Recre

ation

al gr

ound

fish

Recre

ation

al fis

h

Comm

ercia

l salm

on n

et

Comm

ercia

l gro

undf

ish (t

rawl ta

ken

out)

Comm

ercia

l salm

on tr

oll

Comm

ercia

l bot

tom

traw

l

Activities with an average cell value > 0.01

Ave

rag

e ce

ll va

lue

Figure 9. Stressors resulting from marine activities by average raster cell value, using the small buffer assumption (1 km). This figure isavailable in colour online at www.interscience.wiley.com/journal/aqc

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Comm

ercia

l pra

wn

Comm

ercia

l urc

hin

Recre

ation

al cr

ab

Comm

ercia

l her

ring

roe

Shippin

g lan

e

Ferry

doc

k

Dispos

al

Comm

ercia

l cra

b

Comm

ercia

l shr

imp

Recre

ation

al gr

ound

fish

Ferry

rout

es

Recre

ation

al fis

h

Comm

ercia

l salm

on n

et

Comm

ercia

l gro

undf

ish (t

rawl ta

ken

out)

mar

ina

Cruise

ship

rout

es

Finfish

aqu

acult

ure

Indu

stry

Comm

ercia

l salm

on tr

oll

Comm

ercia

l bot

tom

trawl


Ave

rag

e ce

ll va

lue

Figure 10. Stressors resulting from marine activities by average raster cell value, using the medium buffer assumption (up to 5 km).This figure is available in colour online at www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

shift towards an ecosystem approach (Government of Canada, 2002a). While the strategy has been in placesince 2002, progress in achieving it has been very slow (Jessen and Ban, 2003; Office of the Auditor Generalof Canada, 2005). In British Columbia, most aboriginal groups have not signed treaties, and all have a rightto fish for food, social and ceremonial purposes. Successful implementation will require meaningfulinvolvement of aboriginal people (Government of Canada, 2002b).

Data issues

The marine uses considered for this analysis were limited by data availability (Table 2). The resulting mapsshould therefore be considered a preliminary and conservative estimate of human use of the ocean in BC.Many human activities and influences were not included in the analysis because data were unavailable(Table 2). Therefore the emphasis in this analysis is on the general patterns of use, not the precise locationsof activities and influences. As such, this static assessment of anthropogenic stressors is not sufficient tocomprise a complete picture of anthropogenic stressors and their impacts.

The resolution and accuracy of the data that exist for BC vary. For extractive uses, areas delineated byDFO were used. These data were collected from 1992 to 2002 from a variety of sources and compilers,including interviews with fisheries officers and managers, commercial and recreational fishermen and otherrecords. While the metadata indicate that the accuracy of the information is good, they do not provideinformation about the completeness of the datasets. Using DFO’s logbook data for all fisheries would bepreferable, as it would provide up-to-date and complete coverage of fishing areas. Unfortunately densityinformation was not uniformly available for all data layers, and was therefore excluded from the analysis.

0

0.2

0.4

0.6

0.8

1

1.2

Moo

rage

Comm

ercia

l pra

wn

Comm

ercia

l urc

hin

Recre

ation

al cr

ab

Comm

ercia

l her

ring

roe

dock

sPier

Ancho

rage

Terre

strial

mini

ng

Comm

ercia

l cra

b

Comm

ercia

l shr

imp

Recre

ation

al gr

ound

fish

Boat la

unch

Recre

ation

al fis

h

Shippin

g lan

e

Comm

ercia

l salm

on n

et

Comm

ercia

l gro

undf

ish (t

rawl ta

ken

out)

Built a

rea

Ferry

rout

es

Cruise

ship

rout

es

Ferry

doc

k

Comm

ercia

l salm

on tr

oll

Dispos

al

mar

ina

aqua

cultu

re

Finfish

Comm

ercia

l bot

tom

traw

l

Indu

stry


Ave

rag

e ce

ll va

lue

Figure 11. Stressors resulting from marine activities by average raster cell value, using the large buffer assumption (up to 25 km). Thisfigure is available in colour online at www.interscience.wiley.com/journal/aqc



DOI: 10.1002/aqc

The buffers used for mapping stressors are based on a limited number of studies that report on thedistance beyond which activities are having a measurable impact (Table 3). Yet many of these studies werenot designed to measure the maximum detectable distance of impacts, and therefore the distances in Table 3are minimum estimates. For example, a study measuring the effects of acid mine drainage from a coppermine on blue mussels measured mussel survival 2.1 km north and 1.7 km south of the mine (Grout andLevings, 2001). Acid mine drainage was deleterious to blue mussels at least to this distance, but it isunknown how far beyond these limits the impact may have been felt. Similarly, activities can have multipletypes of impacts. For example, finfish aquaculture has effects on the substrate immediately below the seapen, serve as a vector for sea lice infestations, contribute to the introduction of exotic species throughescapes, and are dependent on fishing to produce their feed (Milewski, 2000; Dalton, 2004; Krkosek et al.,2005). The geographic extent of each of these stressors will probably vary.

Ecological considerations

Little is known about the response of multi-trophic marine communities to multiple anthropogenicstressors (Petchey et al., 2004). Because of the limited understanding of such interactions, in this analysisthe simplifying assumption is that activities have an additive effect. In reality, stressors can be synergistic, orcumulative, when the combined effect is larger than the additive effect of each stressor would predict (Foltet al., 1999; Vinebrooke et al., 2004). Stressors can also be antagonistic, when the impact is less thanexpected (Folt et al., 1999; Vinebrooke et al., 2004). How individuals or species react to multiple stressorsdepends on the ability of individuals or species to tolerate each stressor, termed co-tolerance (Vinebrookeet al., 2004). When positive co-tolerance is observed, ecosystem functioning will be more likely to withstandan additional stressor. Negative co-tolerance would probably result in an increased decline or loss of species

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

Commercial Recreational Transportationandfishing fishing

infrastructure

Terrestrial uses Aquaculture

Su

m o

f av

erag

e ce

ll va

lues

small (0-1 km) buffers

medium (0-5 km) buffers

large (0-25 km) buffers

Figure 12. Stressors resulting from marine activities by category.



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with additional stressors (Vinebrooke et al., 2004). Examples of both responses have been observed inaquatic environments (Folt et al., 1999; Lotze and Milewski, 2004; Vinebrooke et al., 2004; Scheffer et al.,2005). In addition, a debate exists in the ecology literature about whether more diverse ecosystems are morestable (the diversity–stability debate) (Grime, 1997; Huston, 1997; McGrady-Steed et al., 1997; Naeem andLi, 1997; Doak et al., 1998; Tilman et al., 1998; Schlapfer and Schmid, 1999; Tilman, 1999, 2000; Chapinet al., 2000; Ghilarov, 2000; McCann, 2000; Loreau and Hector, 2001; Loreau et al., 2001; Naeem, 2002).One hypothesis suggests that the stability of ecological communities is affected by the interaction strengthsbetween predators and their prey (de Ruiter and Neutel, 1995; Bascompte et al., 2005), and therefore thestructure of a community will affect its response to stressors.

The frequency and magnitude of natural disturbances will influence the response of individuals, speciesand functional groups to anthropogenic stressors (Hughes and Connell, 1999; Nystrom and Folke, 2001).Similarly, the history of natural and anthropogenic disturbances in any particular area will affect theresponse of individual, species and functional groups to additional natural or anthropogenic stressors(Lotze and Milewski, 2004). Thus environments also vary in their sensitivity to particular stressors givenboth the habitat structure and past impacts (Zacharias and Gregr, 2005). For example, a muddy substratesubject to frequent natural disturbance events such as storms that perturb the sediment will be less sensitiveto trawling than an area that comprises deep sea corals. Such less physically stable habitats are generallyinhabited by more opportunistic species that are better able to recover from trawling until a thresholdbeyond which the system enters a permanently altered state (Collie et al., 2000). Because of the lack ofspatial data on natural disturbance regimes and historical human use, a limitation of this analysis is thatonly recent anthropogenic stressors were mapped.

0

2,000,000

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6,000,000

8,000,000

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12,000,000

Commercial Recreational Transportationandfisheriesfisheries

infrastructure

Terrestrialuses

Aquaculture

Are

a (h

a) small (0-1 km) buffer

medium (0-5 km) buffer

large (0-25 km) buffer

Figure 13. Area impacted by categories of marine activities.



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Future direction

Given the confounding effects of positive and negative co-tolerance, natural disturbances, and pastanthropogenic impacts, it is unknown whether or how the maps of intensity of use and anthropogenicstressors translate into ecological impacts in the ocean. Additional mapping that incorporates models of thevulnerability and sensitivity of habitats to different types of stressors (sensu Zacharias and Gregr, 2005)would contribute to understanding the impacts such stressors may have on the marine environment.Including the risk of impact from activities, and the potential contribution of planned and potentialdevelopments (e.g. port expansions, oil and gas development, inshore tanker traffic) would further enhancethe assessment. Plans for undertaking such additional mapping work are under way. A future step inverifying the analysis would be to ground-truth the results and determine whether a correlation betweenimpacts and the areas mapped as having a high level of stressors exists.

CONCLUSION

The purpose of this paper was to depict the intensity of use, and evaluate the sum of stressors resulting fromhuman activities in British Columbia, Canada. Results show that the continental shelf and slope of BritishColumbia is extensively and in places intensively ‘used’ by humans, yet very little protection is offered to themarine environment. The analysis provides a preliminary and conservative look at the patterns andintensity of use and resulting stressors given the limited spatial data currently available. The resulting maps

Table 5. Marine protection in British Columbia

Protection provided Hectares PercentageofEEZ

Percentage ofcontinentalshelf

Marine ProtectedAreas

Variable 93 812 0.21% 0.00%

RockfishConservationAreas

Recreational fishing activities allowed arehand-picking or diving for invertebrates,crab by trap, prawn by trap, smelt bygillnet. Commercial fishing activitiesallowed are invertebrates by hand-pickingor dive, crab by trap, prawn by trap,scallops by trawl, salmon by seine or gillnet,herring by gillnet, seine and spawn-on-kelp,sardine by gillnet, seine, and trap, smelt bygillnet, euphausiid (krill) by mid-watertrawl, opal squid by seine, and groundfishby mid-water trawl (Fisheries and OceansCanada, 2005)

393 152 0.87% 2.93%

ProvincialProtectedAreas, ProvincialParks, MarineParks, NationalParks, EcologicalReserves

None to variable 237 635 0.52% 1.77%

Totala 666 078 1.47% 4.69%

aSome areas have multiple designations, and therefore the columns do not add up to form the total.



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can be used as a baseline of human activities for comparison with future analyses. The results may alsoassist in the development of integrated management plans by providing a spatial representation of thelocation of activities.

As this study has shown, even when mapping only current stressors for which spatial data exist, most ofthe marine environment is affected by stressors resulting from human activities. Given the extent of use ofthe ocean in BC and the paucity of protected areas, it is paramount that additional protection is offered tostop degradation and assist recovery while additional research is carried out on the impact and location ofhuman activities. With the limited number areas that are either fully protected or not currently exploited, arelated issue is the lack of reference areas to which impacted areas can be compared. Without a baseline tocompare to degraded systems, compounded with the ‘shifting baselines syndrome’ (Pauly, 1995), it becomesvery difficult to gauge the impact of human activities. The establishment of areas where direct impacts areeliminated can provide a basis for comparison to impacted areas. Yet anthropogenic activities can have animpact many kilometres beyond the location of occurrence, and thus even fully protected areas willprobably continue to receive some stressors from outside of the boundaries.

ACKNOWLEDGEMENTS

The Province of British Columbia’s State of the Coastal and Marine Environment Report instigated the work for thispaper. We thank two reviewers, John Roff and Norm Sloan, and the editor of Aquatic Conservation: Marine andFreshwater Ecosystems, John Baxter, for their helpful comments. We would like to extend particular gratitude toAmanda Vincent for her detailed comments on earlier versions of the manuscript. Drafts of this paper have benefitedfrom the feedback of many people: colleagues at Project Seahorse, Jeff Ardron, Stephen Ban, Brad Barr, Doug Bifford,Sylvie Guenette, Sabine Jessen, Kaaren Lewis, James Quayle and Jodi Stark. We would also like to thank all those whogenerously provided data. Funding for the primary author is provided by: The Canon National Parks Science ScholarsProgram, Natural Science and Engineering Research Council of Canada (NSERC), NSERC industrial postgraduatescholarship in combination with the Canadian Parks and Wilderness Society } British Columbia Chapter, OceanManagement Research Network Integrated Management graduate student seed grant, and Mountain EquipmentCooperative studentship. Jackie Alder is supported by the Sea Around Us Project.

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