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Apr 5, 2012 - ABSTRACT: Concern has been voiced in recent years regarding the environmental implica- tions of the Antarctic krill fishery. Attention h...
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Life Cycle Environmental Impacts of Three Products Derived from Wild-Caught Antarctic Krill (Euphausia superba) Robert W. R. Parker* and Peter H. Tyedmers School for Resource and Environmental Studies, Dalhousie University, 6100 University Avenue, Halifax, Nova Scotia, Canada, B3H 4R2 S Supporting Information *

ABSTRACT: Concern has been voiced in recent years regarding the environmental implications of the Antarctic krill fishery. Attention has focused primarily on ecological concerns, whereas other environmental aspects, including potentially globally problematic emissions and material and energy demands, have not been examined in detail. Here we apply life cycle assessment to measure the contributions of krill meal, oil, and omega-3 capsules to global warming, ozone depletion, acidification, eutrophication, energy use, and biotic resource use. Supply chains of one krill fishing and processing company, Aker BioMarine of Norway, were assessed. Impacts of krill products were found to be driven primarily by the combustion of fossil fuels onboard the fishing vessel and a transport/resupply vessel. Approximately 190 L of fuel are burned per tonne of raw krill landed, markedly higher than fuel inputs to reduction fisheries targeting other species. In contrast, the biotic resource use associated with extracting krill is relatively low compared to that of other reduction fisheries. Results of this study provide insight into the broader environmental implications of the krill fishery, comparisons between products derived from krill and other species targeted for reduction, opportunities for improving the fishery’s performance, and a baseline against which to measure future performance.

1. INTRODUCTION Global food production systems contribute significantly to environmental change at all scales though resource consumption, habitat alteration, material and energy demands, and resulting emissions to air and water.1−5 The provision of seafood from wild and cultured sources is associated with a wide range of environmental alterations.6−11 Energy use and related emissions can be highly heterogeneous across fisheries and seafood culture systems,12−15 and have been found to vary with target species, technologies and gears, and the locale of fishing or culture operations.13−18 In recent years, wild fisheries have been characterized by wide-scale depletion of many stocks, with most being exploited to capacity or overexploited.9,19,20 Opportunities for expansion are scarce, and a rapidly increasing portion of global demand for seafood is being met by aquaculture production.7,20,21 Fisheries targeting small pelagic species for industrial purposes, most notably inputs to livestock and aquaculture feeds,21−23 currently make up some of the largest fisheries in the world.20 Antarctic krill (Euphausia superba) is a relatively unexploited marine resource which has attracted attention in recent years as a potential source of meal and oil inputs to aquaculture supply chains as well as numerous other products. This fishery may provide a unique opportunity for growth in coming years, and improved understanding of the environmental implications of an expansion in this fishery is needed. 1.1. The Antarctic Krill Fishery. Antarctic krill are small shrimp-like crustaceans belonging to the order Euphausiacea. Of the 85 known species of euphausiids, Antarctic krill are the most abundant, the longest lived, and the most commercially significant.24,25 They are found in the seasonal pack-ice zone between the Antarctic continent and the polar front, with © 2012 American Chemical Society

greatest abundances occurring in the Atlantic sector of the Southern Ocean.26−28 Estimates of total Antarctic krill biomass vary, with recent estimates between 37 and 208 million tonnes, making them one of the most abundant animal species on the planet.29−32 The modern industrial fishery for Antarctic krill began in the early 1970s and catches were dominated by the Soviet Union until 1992.27,33,34 Since the collapse of the Soviet Union, a number of countries have remained active in the fishery, although fishing levels have been far below those of the 1980s. In recent years, Norway has been the most prominent country in the fishery, accounting for one-third of total reported catches from 2007 to 2009, and over half of 2010 landings.35,36 Uses for Antarctic krill products have included direct human consumption of whole krill, tail meat, or processed sauces and pastes; feed products for aquaculture and aquarium fish; fish bait for sport and commercial fishing; extraction of chitin from shells for industrial purposes; and use of enzymes and krill oil for medical and nutritional purposes.37,38 Recent demand for Antarctic krill products has been driven by the aquaculture industry, arising from evidence that krill inputs to aquafeeds may enhance fish growth and feeding behavior,39−41 and by promotion of omega-3 rich krill oil supplements by the nutraceutical industry.42−44 Until recently, fishing, processing and marketing challenges, including highly variable resource distributions, rapid post-mortem decomposition, and the lack of a marketable, value-added product, Received: Revised: Accepted: Published: 4958

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Figure 1. Product supply chains of krill meal, krill oil, and omega-3 krill oil capsules.

have kept the fishery from expanding.45,46 However, with the development of new fishing and processing technologies,47,48 improved product quality and increased demand, the fishery is set to grow in coming years. This potential for expansion has raised alarm in some circles regarding possible ecological consequences of significantly increased extraction.49−52 Concerns include potential effects on predators and uncertainty regarding krill biomass estimates, as well as effects on Antarctic krill populations by changes in sea ice and ocean acidification associated with increasing atmospheric CO2 levels.53,54 While population status and ecological impacts of Antarctic krill extraction have received much attention in the literature, other resource and environmental performance characteristics have been largely overlooked. Specifically, contributions to broad environmental concerns such as global warming and depletion of energy resources have been excluded from analyses of the fishery. Here we use life cycle assessment (LCA)55,56 to examine supply chains of one krill fishing and processing company, Aker BioMarine ASA of Norway (AB), and quantify and characterize life cycle environmental burdens associated with three Antarctic krill-derived products. Analysis focuses on contributions of krill-derived products to energy use, biotic resource use (BRU), and emissions of greenhouse gases and other potentially environmentally destructive substances. Results should be of interest to krill-fishing companies, customers of krill-derived products in the aquaculture and nutraceutical industries, consumers of farmed fish and omega-3 supplements, fisheries management authorities, and LCA practitioners, as well as any other organizations and individuals interested in better understanding the environmental implications of the Antarctic krill fishery and its associated products.

krill-derived products, to identify hot spots of environmental impact along the krill product supply chain, and to model potential improvement opportunities. Supply chains of three products were assessed: 1 kg krill meal, 1 L krill oil, and 1 consumer-ready bottle of 60 omega-3 krill oil capsules. Products were evaluated on the basis of six environmental impact categories: global warming potential (GWP, measured in carbon dioxide equivalent emissions [CO2-e]); cumulative energy demand (CED, in megajoules [MJ]); ozone depletion potential (ODP, in trichlorofluoromethane equivalent emissions [CFC-11-e]); acidification potential (AP, in sulfur dioxide equivalent emissions [SO2-e]); eutrophication potential (EP, in phosphate equivalent emissions [PO4-e]); and BRU expressed as net primary productivity (NPP) appropriation. Antarctic krill product supply chains were represented here by AB’s operations and processes. The system boundary included all activities up to the point of delivery to aquaculture clients and nutraceutical retailers, including fishing, processing, packaging, intermediate transport, and distribution (Figure 1). Processing of Antarctic krill into meal and oil takes place directly onboard AB’s fishing vessel, Saga Sea, while omega-3 krill oil capsules are processed at a secondary facility in France. Intermediate transportation includes both transport of processed meal and oil from the fishing vessel to port in Montevideo, Uruguay, via a resupply vessel, La Manche, and transport of a small portion of meal to France for secondary processing into omega-3 krill oil capsules. Background processes considered included coarse inputs to vessel construction and maintenance, manufacturing of gear, production of fuel, production of all packaging materials, and production of electricity for processing. Storage, consumer use and disposal stages of the product life cycle were excluded from analysis. 2.2. Life Cycle Inventory. Data relating to krill capture and processing, including vessel characteristics, fuel use, energy, and material inputs to processing, packaging materials, and transportation routes and modes, were solicited from AB via

2. MATERIALS AND METHODS 2.1. Goal and Scope. The objectives of this study were to quantify the life cycle environmental burdens associated with 4959

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carbon content of U.S. pig fodder and reported feed use rates.58,59 2.4. Sensitivity and Scenario Analyses. Sensitivity of results to the choice of allocation procedure was assessed by comparing the life cycle impact results for omega-3 capsules using three different allocation scenarios: (a) base case scenario, using energy allocation for fishing and primary processing into meal and oil, mass allocation for transport of meal to port, and system expansion to allocate between omega-3 capsules and lower grade meal; (b) energy-based allocation throughout, except for transport of meal to port (mass); and (c) mass allocation throughout the entire supply chain. Economic allocation was not included in the sensitivity analysis as coproduct revenue data were not available. In addition to the allocation sensitivity analyses, six scenarios were independently modeled to explore potential environmental performance implications of possible changes to Antarctic krill product supply chains. These included sensitivity of results to uniform (10%) changes in fuel use, distribution distance, packaging, and meal yield; transitioning to a low-sulfur marine fuel mix; and using air freight, rather than container vessel, to transport products.

surveys and personal communications. Additional data relating to secondary processing of omega-3 krill oil capsules were solicited from a France-based processor, and data pertaining to construction of fishing gear were solicited from a trawl gear manufacturer which supplies AB. Material and energy inputs to the production of gelatin for omega-3 krill oil capsules were solicited from a Canadian gelatin manufacturer, and characterized as either processingrelated or base material-related, where the base material was assumed to be pig skin. Atmospheric emissions from gelatin processing were not available; however, eutrophying emissions to water were estimated based on the difference between the stoichiometric composition of dry, unprocessed pig skin and that of the extracted collagen, assuming that remaining nitrogen and phosphorus is entirely emitted to water.57 Energy use and emissions associated with pig production were taken from Pelletier and colleagues.58 Slaughtering and transport activities associated with pig skins were excluded, as was transportation of finished gelatin. Background data for upstream processes relating to construction, packaging and processing materials, energy production, and transportation were compiled from the EcoInvent 2.0 database of European life cycle inventory data.59 Fuel-specific properties and emissions relating to burning marine diesel oil (MDO) and intermediate fuel oil (IFO) fuels were used to supplement heavy fuel oil processes in EcoInvent 2.0 to allow for comparison of energy carriers.59 The need to allocate environmental burden of processes between coproducts was encountered several times throughout the krill product supply chains. Coproduct allocation is a common methodological challenge in LCAs of seafood products, and has been handled in several ways in previous LCAs of wild-caught fisheries products.60 Here, environmental burden needed to be allocated between coproducts from fishing, primary processing of krill into meal and oil, secondary processing of omega-3 krill oil capsules from meal, and intermediate transportation throughout. In assessing meal and oil products destined for aquafeeds, relative energy content (mass multiplied by energy density) was used as the basis for allocation, as the provision of nutritional energy is a central attribute of both products. However, mass and volume, rather than energy, are the limiting factors in transportation, and so mass was used as the basis of allocating burdens associated with transporting krill products to port. Allocation also arises when omega-3 rich oil is stripped from krill meal leaving a lower grade meal coproduct. Here system expansion was applied. Specifically, lower grade meal was allocated an environmental burden equal to that of an energetically equivalent quantity of higher grade meal, with all residual impacts associated with omega-3 oil production being borne by the omega3 oil (see Supporting Information (SI) for details). 2.3. Impact Assessment. Inventory data were compiled and analyzed using SimaPro 7.0 software from PRé Consultants. Energy use was characterized by MJ energy input, from both renewable and nonrenewable sources.61 CML 2 Baseline 2000 characterization models were applied to quantify contributions to GWP, ODP, AP and EP.62 Quantification of BRU associated with krill extraction followed the NPP appropriation formula developed by Pauly and Christensen,63 which has been previously applied in other seafood product-related LCAs.64−66 BRU associated with the use of pig skin for gelatin production was estimated from the

3. RESULTS 3.1. Inventory Analysis. Operational inputs to fishing, processing, packaging and transportation were secured for three seasons of operation spanning from 2007 to 2009 (see SI). Over these years, AB harvested an average of 45, 700 metric tonnes of krill per annum, accounting for 35% of the total harvest of Antarctic krill from the Southern Ocean during that period. From this harvest, AB produced approximately 144 kg of meal and 0.8 L of oil per tonne of krill, as well as 7.2 kg of krill paste product for unspecified development purposes. Together, fishing, processing, and transportation of processed meal and oil were found to require 256 L of fuel per tonne of krill harvested. Meal is packaged in plastic-lined nylon bags requiring 19 g of packaging per kg of meal. Oil is packaged in plastic bottles and plastic-lined cardboard drums, requiring 67 g of packaging per liter of oil. After landing in Montevideo, meal and oil are shipped globally by container vessel and truck. A small portion of meal is further reduced into omega-3 oil and lower grade meal using ethanol extraction; 168 g of meal input is required to produce 30 g of omega-3-rich oil and 138 g of a lower grade meal byproduct. Omega-3 is packaged in porcine-derived gelatin capsules at a ratio of 225 mg gelatin to 500 mg oil, and subsequently in cardboard boxes for transport and 60-capsule plastic bottles for distribution. Capsules are shipped primarily to markets in Norway and the United States via container vessel and truck. 3.2. Impact Assessment. Krill meal and oil have similar environmental profiles when assessed against the six impact categories chosen (Table 1), although oil appears to contribute more heavily to all impact categories as a result of energy-based allocation which places more burden from non-transport joint activities on products with greater energy density. On a massto-mass basis, omega-3 krill oil capsules contribute markedly more to all energy- and emissions-based impact categories as a result of additional processing activities and a higher ratio of packaging to product. Fishing, processing of krill onboard the fishing vessel, and transport of processed meal and oil to port by a resupply vessel together account for an average of 96 and 97% of total impacts 4960

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Table 1. Contribution by Life Cycle Stage to Environmental Burden of Krill-Derived Meal, Oil, And Omega-3 Capsulesa GWP (kg CO2-e) 1 kg meal fishing processing transport packaging distribution

5.4 2.0 1.0 2.2 0.1 0.1

1 L oil fishing processing transport packaging distribution 60 omega-3 capsules fishing processing (meal) transport to port secondary transportb secondary processingc pig skin production gelatin processing nongelatin packagingd distribution

CED (MJ)

ODP (mg CFC-11-e)

(36%) (19%) (40%) (3%) (3%)

80 29 (36%) 15 (19%) 32 (40%) 2 (3%) 2 (3%)

0.64 0.24 0.13 0.27 0.00 0.02

7.1 3.2 1.6 2.0 0.1 0.1

(45%) (23%) (29%) (2%) (2%)

106 46 (44%) 24 (23%) 30 (28%) 2 (2%) 4 (4%)

0.95 0.14 0.07 0.15 0.02 0.43 0.07 0.01 0.06 0.00

(14%) (7%) (16%) (3%) (45%) (7%) (1%) (6%) (0%)

28.4 2.0 (7%) 1.0 (4%) 2.3 (8%) 0.4 (1%) 20.1 (71%) 0.3 (1%) 0.6 (2%) 1.7 (6%) 0.1 (0%)

AP (g SO2-e)

(37%) (19%) (41%) (0%) (3%)

134 49 26 55 1 3

0.85 0.38 0.20 0.25 0.00 0.02

(45%) (24%) (29%) (0%) (2%)

0.103 0.017 0.009 0.019 0.003 0.052 0.001 0.001 0.002 0.000

(16%) (9%) (18%) (3%) (50%) (1%) (1%) (2%) (0%)

EP (g PO4-e)

(37%) (20%) (41%) (0%) (2%)

15.7 5.7 3.1 6.5 0.1 0.3

176 79 42 51 1 3

(45%) (24%) (29%) (0%) (2%)

13.6 3.4 1.8 3.9 0.4 1.9 1.7 0.1 0.2 0.1

(25%) (14%) (29%) (3%) (14%) (12%) (1%) (2%) (1%)

BRU (kg C)

(37%) (20%) (42%) (1%) (2%)

12 12 0 0 0 0

(100%) (0%) (0%) (0%) (0%)

20.4 9.2 4.9 6.0 0.2 0.1

(45%) (24%) (29%) (1%) (0%)

19 19 0 0 0 0

(100%) (0%) (0%) (0%) (0%)

2.44 0.40 0.21 0.46 0.03 0.53 0.46 0.29 0.05 0.01

(17%) (9%) (19%) (1%) (22%) (19%) (12%) (2%) (0%)

0.89 0.82 0 0 0 0 0.1 0 0 0

(91%) (0%) (0%) (0%) (0%) (9%) (0%) (0%) (0%)

a

Note: Individual values may not add to totals, and percentages may not add to 100, due to rounding. For detailed impact assessment results, see Supporting Information. bIncludes transport to France for further processing, and transport to a UK-based distributor. cFrance-based secondary processing to extract oil from meal. dIncludes packaging of capsules in cardboard boxes for transport, and packing in bottles for distribution.

across energy and emissions-based impact categories for meal and oil, respectively (Table 1). Combustion of fossil fuels accounts for 95% of impacts up to delivery of meal and oil at port. Vessel construction and maintenance, gear provision, and upstream activities associated with fuel together account for less than 2% of total impacts of meal and oil. Similarly, postlanding packaging and distribution by container vessel and truck also contribute insignificantly (Table 1). While fishing, processing of meal, and transport of meal to port contribute significantly to overall burden of omega-3 krill oil capsules, secondary processing to extract omega-3 oil from meal is the clear driver of several impacts. In particular, CED is driven primarily by secondary processing in France (71%); the effect on GWP is still substantial (45%), though less so due to the role nuclear energy plays in French electricity production. Further, packaging also contributes more heavily to impacts associated with omega-3 capsules than to those of krill meal and oil, accounting for 15% and 31% of overall AP and EP, respectively. Porcine production and emissions from gelatin processing in particular contribute heavily to overall eutrophying emissions (Table 1). BRU associated with each krill-derived product is generally a direct reflection of allocated product yields from whole krill. The fishing stage, therefore, accounts for all BRU associated with krill meal and krill oil, and the majority of BRU associated with omega-3 krill oil capsules. However, a small portion of the BRU burden of omega-3 krill oil capsules (13%) also results from crop-derived inputs to pork production in the gelatin supply chain (Table 1). 3.3. Sensitivity and Scenario Analyses. 3.3.1. Allocation Sensitivity. Life cycle impact assessment results for

Table 2. Scenario Analysis of Omega-3 Krill Oil Capsule Life Cycle Impacts Using Three Different Allocation Methodsa value (and % change from base case) impact category GWP CED ODP AP EP BRU

(kg CO2) (MJ) (mg CFC-11) (kg SO2) (kg PO4) (kg C)

base case (system expansion)b 0.95 28.4 0.103 13.6 2.44 0.89

energy allocationc 0.55 13.1 0.054 9.5 1.77 0.66

−42% −54% −48% −30% −27% −26%

mass allocationd 0.35 8.1 0.031 6.0 1.32 0.40

−63% −71% −70% −56% −46% −55%

a

Note: Revenue data were not available to model results using economic allocation. bSystem expansion used to allocate between omega-3 capsules and lower grade meal byproduct; energy allocation used for fishing and primary processing; mass allocation used for transport to port. cEnergy allocation used for all coproduct allocation except transport to port (mass). dMass allocation used for all coproduct allocation.

omega-3 krill oil capsules were found to be highly sensitive to the method of allocation used (Table 2). Applying strictly energy-based or mass-based allocation procedures to divide environmental burden among coproducts, rather than a combination of system expansion and energy allocation, resulted in outcomes on average 38% and 60% lower, respectively. 3.3.2. Scenario Analysis. Not surprisingly, decreasing fuel consumption by the fishing and/or resupply vessels yields marked potential for improvement across most impact categories, particularly in the case of meal and oil production (Table 3). This is particularly the case for meal and oil products destined for 4961

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Table 3. Modeled Changes in Emissions and Energy and Biotic Resource Use as a Result of Potential Changes Made to Krill Meal and Omega-3 Krill Oil Capsule Supply Chains, Relative to Baseline Analysisa scenario 1 2 3 4 5 6

resulting change in meal impacts (%) GWP −9.4 0.2 0.2 −4.6 −2.0 243.5

ODP −9.7 0.2 0.0 −4.8 −3.1 261.8

AP −9.7 0.0 0.0 −5.2 −36.0 36.0

EP −9.6 0.0 0.0 −5.1 −3.2 54.4

CED −9.5 −0.2 −0.2 −4.7 −3.2 257.7

resulting change in capsule impacts (%) BRU 0.0 0.0 0.0 −9.1 0.0 0.0

GWP −3.0 0.0 −1.4 −2.0 −0.7 33.8

ODP −3.4 −0.0 −0.4 −2.2 −1.3 39.4

AP −5.4 −0.1 −1.4 −3.5 −24.9 9.0

EP −3.5 0.0 −3.3 −2.3 −1.3 8.2

CED −1.5 0.0 −0.9 −1.0 −0.5 17.3

BRU 0.0 0.0 −0.9 −8.2 0.0 0.0

Note: Scenario 1, 10% reduction in fishing/transport to port fuel use; Scenario 2, 10% reduction in distribution distance; Scenario 3, 10% reduction in packaging materials; Scenario 4, 10% increase in krill meal yield; Scenario 5, 100% MDO fuel mix on fishing/resupply vessels; Scenario 6, distribution by air freight. a

performance over time.12,14,16 On the basis of unprocessed landings transported to port, the FUI of Antarctic krill is relatively low when compared to many high-value commercial species such as cod, tuna, or lobster,12,16,67−70 but markedly higher than has been documented for other fisheries targeting species for reduction into meal and oil (Table 4).

aquafeeds: a reduction in fuel consumption on either vessel would be expected to provide an almost equal reduction in life cycle energy use and emissions. Increasing meal yield would also result in substantial improvements across impact categories, although not to the extent that a direct fuel reduction would. Substantial improvement in AP would be realized by switching to a low-sulfur fuel: transitioning to a fuel mix of all MDO on both vessels would result in modeled reductions in life cycle acidifying emissions of 36% for krill meal and 25% for omega-3 krill oil capsules. Interestingly, by far the most significant overall changes to life cycle environmental costs of krill-derived products modeled would result if products were distributed by air. Shipping krill meal by air rather than by container vessel, for example, would more than triple life cycle GHG emissions and energy use (Table 3). Importantly, modeled potential improvements to BRU in the life cycles of both krill meal and omega-3 krill oil capsules follow different patterns than those modeled for other impact categories, because BRU is not related to fuel use. The only scenario modeled here that would see improvements in BRU is an increase in meal yield per tonne of krill harvested. A 10% increase in meal yield would translate to a 9.1% decrease in BRU associated with meal and an 8.2% decrease in BRU associated with omega-3 krill oil capsules (Table 3).

Table 4. Reported FUI of Fisheries Targeting Species for Reduction gear (if known)

fishery Capelin/Atlantic herring12 Sand eels/ Atlanticerring12 Atlantic herring/ mackerel12 Atlantic herring71 Antarctic krill Capelin/Atlantic herring12 Atlantic herring71 Gulf menhaden12 South American pilchard72 Atlantic mackerel73

4. DISCUSSION Fisheries for Antarctic krill represent a potentially important source of nutritionally valuable products for a number of uses. However, products derived from this fishery are associated with a number of challenges and concerns regarding the environmental implications of fishing and processing krill. Energy use and related GHG emissions in the krill product life cycle are largely dominated by the fishing and transport-toport stages. This is consistent with previous LCAs of wildcaught fishery products, which have found the fishing stage (which typically includes both fishing and transporting unprocessed fish to port) to account for between 60 and 90% of life cycle GHG emissions.17,67−69 Interestingly, in the supply chain of Antarctic krill products, fuel consumption by a secondary resupply vessel used to transport meal and oil from the fishing vessel to port accounts for roughly the same magnitude of energy use and emissions as fuel consumption on the fishing vessel (see SI). This suggests that the distance between the fishing vessel and port plays a particularly important role in the life cycle environmental impacts of krill products. Fuel use intensity (FUI), or liters of fuel consumed per tonne wet weight landings (L/t), can be used as one way to compare relative performance of fisheries and track changes in

Blue whiting12 Atlantic herring/ sand eels12 Atlantic Herring73 Peruvian anchovy70 Atlantic herring70 Atlantic mackerel70 Multiple small pelagic14

fuel use fishing locale (if known) intensity (L/t)

trawl

North Atlantic Ocean

80

trawl

North Atlantic Ocean

95

trawl

North Atlantic Ocean

110

Northwest Atlantic Ocean trawl Atlantic sector of Southern Ocean purse seine North Atlantic Ocean

118

purse seine Northwest Atlantic Ocean purse seine North Atlantic Ocean purse seine Indian Ocean

21

purse seine Northeast Atlantic Ocean purse seine North Atlantic Ocean purse seine North Atlantic Ocean

80

purse seine Northeast Atlantic Ocean purse seine Southeast Pacific Ocean

140

trawl

Northeast Atlantic Ocean

191a 20

32 42−112b

85 100

19 91 94 106

a Fuel use intensity for Antarctic krill reflects fuel consumed during fishing (65% of total fuel use by the fishing vessel) and transport by the resupply vessel, and excludes fuel burned for onboard processing on the fishing vessel. bRange shows variation of fuel use intensity between three years of fishing.

Reductions in fuel consumption in the Antarctic krill fishery could be realized by reducing the number of trips between the fishing vessel and port, reducing the distance of fishing grounds to port, improving engine efficiency, or increasing either krill catch or processed yield relative to fishing effort. Emissions 4962

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improve the performance of farmed fish products through strategic input selection. This includes both the choice of source fishery for fish-based inputs, and the option of replacing fish-based products partially or entirely with alternative plantbased ingredients.79 The replacement of fish ingredients with soy and vegetable oil has been shown, in some cases, to improve energy use, emissions, and BRU associated with culture systems.64,66,80 Feasibility studies of transitioning to new feed compositions, though, must consider differences in nutritional content between different species and between plant- and fishbased ingredients. While this study provides an estimate of the contributions of krill-derived products to numerous environmental impacts, a number of limitations and assumptions are inherent in the methods used and should be made clear. Impact assessment was limited to a suite of six environmental impact categories, chosen for their relevance to the system, global importance in policy, and comparability to other LCA studies of wild-caught fisheries. Numerous additional impact categories were excluded (e.g., measures of ecotoxicity, smog production). Additionally, many issues of concern to fisheries managers and consumers were not assessed as they do not readily lend themselves to quantification in LCA studies, including habitat alteration and impacts on populations of krill and krill predators. The system boundaries of the study excluded impacts associated with activities past the point of departure into aquaculture systems or retail of omega-3 products. Assessment of upstream processes is limited by the availability and relevance of secondary life cycle inventory data: in this study, only one inventory database was used (EcoInvent) to maintain consistency, and results are subject to the methods applied by those studies contributing to that database. Finally, while AB’s vessel does account for a substantial portion of the total Antarctic krill harvest and the logistical challenges faced by AB can be assumed to be shared by other vessels fishing in high seas environments, results here are specific to one vessel and can not necessarily be generalized to the entire krill industry or other fisheries. The environmental performance of the Antarctic krill fishery is of particular interest to many stakeholders, and the environmental implications of the fishery are at the heart of much debate. It is critical that these discussions be informed from a variety of perspectives, to bring forward the most holistic understanding of fisheries sustainability. This is the first comprehensive study of the energy use and emissions associated with the Antarctic krill fishery, and findings here will contribute to broadening our understanding of the environmental implications of using Antarctic krill as a resource.

associated with the fishery can also be effectively improved without necessarily decreasing fuel consumption. Ziegler and Hansson,74 for example, found that technological changes (e.g., more efficient engines, cleaner fuels) made at the fishing stage as well as changes in fishing effort could decrease emissions of CO2 by 40% and emissions of several other gases by between 70 and 98%, for cod fisheries in the Baltic. Perhaps one of the most effective long-term options to reduce GWP of Antarctic krill products would be a transition to a cleaner energy carrier, such as natural gas, which has been modeled to reduce emissions of nitrous oxides (NOx) and CO2 from fisheries by 85 and 20%, respectively;75 however, the provision of natural gas to a fishing vessel in the Southern Ocean may be impractical logistically. BRU has been measured previously for meal and oil products derived from numerous fisheries, as well as several culture systems64−66,76 (Table 5). Antarctic krill products are Table 5. BRU Associated with Reduction Fisheries and Culture Systems species Species for Reduction into Meal and Oil Gulf menhaden76 Antarctic krill76 Peruvian anchovy76 Atlantic herring76 Blue whiting76 Aquaculture Species Atlantic salmon culture, Canada66 Rainbow trout culture, fed mostly plantderived feed ingredients64 Rainbow trout culture, fed mostly Norwegian and Peruvian fish meal64 Atlantic salmon culture, Chile66 Turbot culture, France65 Atlantic salmon culture, Norway66 Atlantic salmon culture, UK66

BRU per live weight tonne

BRU per 100 GJ meal and oil

1721 1761 5569 18 869 113 699

16 349 45 786 99 681 215 111 2 694 672

18 400 19 100 41 300 56 600 60 900 111 100 137 200

associated with relatively low BRU when compared to those derived from other species targeted for reduction, largely as a result of Antarctic krill’s relatively low trophic level. The BRU associated with culture systems has been found to be largely driven by feed ingredients, and there is wide variation within culture of a single species depending on the composition of feeds.64,66 Clearly, the source fishery for fish-derived feed inputs greatly influences the BRU of these systems. Currently, the major market for Antarctic krill-derived products is the aquaculture industry. Farming of salmon and other carnivorous fish species relies on inputs from reduction fisheries.7,10,64,66,77,78 While concerns regarding this relationship tend to be focused on the ecological consequences of fishing, reliance on these key fisheries inputs also drives emissions and energy-related environmental impacts of aquaculture production.66 LCAs of culture systems have found that feed provision accounts for upward of 90% of total energy use and related impacts for intensive Atlantic salmon culture, and is also a key driver of many emissions-based impacts.66 Feed inputs are also generally assumed to be the sole driver of NPP appropriation associated with aquaculture of carnivorous species.64−66 The important role that fish-derived inputs play in the life cycle environmental performance of fed aquaculture systems suggests that there is a potentially substantial opportunity to



ASSOCIATED CONTENT

* Supporting Information S

(1) a breakdown of annual krill harvest rates in the Southern Ocean, including total values and Norwegian harvest; (2) nutritional information for krill products; (3) more detailed inventories of the material and energy flows throughout the supply chains of krill meal, oil and omega-3 capsules; (4) a more detailed explanation of allocation procedures employed; and (5) detailed life cycle impact assessment results for each product, broken down by life cycle stage and subprocess.This material is available free of charge via the Internet at http:// pubs.acs.org. 4963

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Notes

The authors declare no competing financial interest.



ACKNOWLEDGMENTS We acknowledge the support of Aker BioMarine and the Natural Sciences and Engineering Research Council of Canada (NSERC). We thank in particular Mr. Sigve Nordrum at Aker BioMarine and all other individuals and companies that assisted by providing data.



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