Measuring the footprint of seafood
Seafood footprint, considered a neglected issue in much of the rubric around fisheries and aquaculture, is defined by the report as “a measure of the efficiency of use of aquatic resources in the production of seafood.” Concentrating on this ecological efficiency is crucial; the ocean’s primary productivity sets the limit to seafood production, so more efficient production means more seafood from whatever the ocean can provide. Thus, seafood footprint is a tool that evaluates how primary production is used in producing seafood. The use of this tool in sustainability assessments can help ensure optimal and responsible use of ocean resources.
“The ecological efficiency of seafood is a measure of how efficiently the farmed species use aquatic primary productivity (APP) to grow,” says Dr Muldoon, Business and Industry Senior Manager, WWF Coral Triangle Coordination Team. “A corollary to this is the feed conversion ratio (FCR)1 of the farmed species−−how efficient the species is in converting feed inputs, such as fishmeal and fish oil, into biomass. Species with high ecological efficiency or low conversion ratios have a low APP requirement. At a time when aquaculture is seen as the only production system capable of ‘feeding the world,’ the demand of farmed species on APP will be critical.”
The report also refines the use of the word “footprint.” While ecological footprint is “a precisely defined measure of the resource requirements of production of seafood or other activities,” the term has also been used generally to refer to ecosystem impacts of human activities.
Trophic level“Ecological footprint” is influenced by the trophic level of wild-caught species, says the report. Trophic level refers to a species’ place on the food chain—basically, what it eats, and what eats it. Thus, low trophic level species make less demands on ocean productivity for their own sustenance, with this attribute being carried over into aquaculture production.
“Seafood from lower trophic level species requires much less primary productivity to produce because the transfer efficiency for ocean animals is around 10 per cent,” the report illustrates. “Thus, 1,000 kg of plant biomass at trophic level 1 can produce 100 kg of herbivore at trophic level 2, 10 kg of predator at trophic level 3 that eats herbivores, and only 1 kg of top predator at trophic level 4 that eats lower level predators. So, low trophic level seafood is described as having a lower seafoodprint.”
This related term, “seafoodprint,” is used to describe the measure of oceanic primary production required to produce ocean species caught in fisheries, as defined by Greenberg, 2010, notes the report. “The specific term seafoodprint has utility in evaluating and managing key aspects of seafood sustainability, the resource efficiency of seafood in utilisation of primary production.”
Because such a seafood footprint has become increasingly relevant, it should be considered in any future development of fisheries and aquaculture in the Coral Triangle. Low footprint aquaculture (LFA), referring to aquaculture with low impacts on ecosystems, is already important in the region in helping ensure food security and livelihoods, says the report. However, footprint measurement is not often included in sustainability assessments in the Coral Triangle. Thus, reliable tools that can cover a range of environmental issues are needed for measurement of seafood footprint for LFA.
The report posits that “the best approach currently available for evaluating the ecosystem impacts of low footprint aquaculture” is WWF’s Foundational Measures (FMs). FMs are comprised of specific, quantitative indicators and can be used for evaluating the sustainability of farmed species. While developed as a simple way of measuring conservation impacts and assessing farm performance, the approach lends itself well to identifying seafood footprint and other environmental impacts. Aside from being relatively simple, FMs are usable at different scales, even with limited data, and designed in a way that is supportive of LFA and its use in subsistence, domestic, or regional markets.
Fish-in fish-outThe report lists seven of the indicators used in the FM approach. The fish-in fish-out ratio (FIFO) is the clearest of the indicators, with LFA species showing low FIFO ranges and more predatory species (like trout or salmon) registering high FIFO ranges.
Other indicators are:
- water use, which will vary according to the different production systems;
- land use, which acknowledges the different types of farming areas used for aquaculture;
- energy use, recognizing that systems that require pumping require the most energy;
- survival of seed stock of different species;
- waste discharge levels, which determines eutrophication caused by aquaculture waste; and
- FCRs, which can be controlled by good feed management practices.
“All aquaculture, regardless of scale, system type, or supply chain, domestic or international, has impact, and while the nature of impacts will be similar across farms and species, performance against these impacts will vary, as will the leverage point for improving individual farming operations,” says Dr Muldoon. “The Foundational Measures approach is about measuring key impacts, and establishing a program to reduce these impacts. The intent of the FM indicators is the same as the Aquaculture Stewardship Council (ASC) standards—that of providing a pathway for improvement that leads to a positive conservation outcome.”
“FMs are common to all aquaculture and are standardized per ton of production, such that subjectivity and interpretation are taken out of the analysis,” confirms Dr Aaron McNevin, WWF-US Director of Sustainable Food.
FMs are a highly appropriate option for aquaculture development in the Coral Triangle, says Dr Muldoon. “ASC standards are considered the most robust and credible for key internationally traded aquaculture products, as they rely on metrics and also practice-based requirements to measure performance and improvement. WWF has initially focused on internationally traded products because of unique opportunities to leverage change with seafood buyers, such as retailers and food service companies. However, the volume of internationally traded products is only one part of the global aquaculture market—likely between 10-18 per cent of total production.”
The fact remains that a vast majority of global aquaculture production is neither destined for export nor suitable for Aquaculture Improvement Projects (AIPs) moving toward ASC, Dr Muldoon concludes—and FMs represent a significant opportunity to leverage change “The FM approach provides a tool for tracking improved performance in a meaningful way for farms and production facilities not focused on export supply chains, and not able to be influencers through international market leverage. The FM approach is rooted in the concept that better environmental performance means a better business and a better bottom line.”
1 Fish Conversion Ratio is one measure of species efficiency in converting feed inputs. Others terms used to describe this relationship include forage fish dependency ratio (FFDR) and fish-in-fish-out (FIFO) both which describe the quantity (kg) of wild fish used in feeds in relation to the quantity (kg) of farmed fish in terms of both fishmeal and fish oil.