Plastics and Microplastics in the Ocean Environment

IFFO Position Paper

Date: 14th August 2017

Author: Neil Auchterlonie

Introduction

The topic of plastic in the marine environment is rapidly gaining traction in the global media.  There is a general recognition that plastics are a problem, and the subject carries with it several points of interest that capture the audience’s attention: human impact on the marine environment, pollution, harm to wildlife, and possible impact on marine food chains and potential contamination in food. This latter issue is potentially the most powerful.

There are several active campaigns, suggesting that the media attention is only likely to increase over time.  This includes campaigns by the UN[1], Greenpeace[2], Marine Conservation Society[3], Sky News[4], The Ocean Cleanup[5], The Plastics Ocean Foundation[6] amongst others.  In the UK, politicians have pledged action and legislation on the subject[7].  Other administrations are developing strategies[8] and laws[9][10][11] to deal with the matter.  It is a topic of rapidly growing importance.  The impacts are visible, at the macro-scale - a project reported in June 2017 in Norway was designed to look into the potential of using trawling as a means to remove some of the larger material[12].

The Level of Current Knowledge

Although the problem seems widely recognised, the science is at a relatively early stage.  A small science review was published for “Plastic Oceans[13]”, which accepts that there are large knowledge gaps.  [Interestingly, and as an aside, some recent science shows that the volumes of marine plastic debris are actually lower than expected, perhaps due to microbial degradation[14].] 

The issues associated with plastics include:

  1. ingestion of plastics and microplastics by marine life, and their impact on the animal’s physiology;
  2. the direct physical harm effect of plastics on fauna,
  3. the consequences for the consumer of eating contaminated seafood (usually focusing on filter feeders such as bivalve molluscs and the subject of microplastics); and
  4. the impact of chemicals which may be associated with the plastics, or, the impact of those chemicals that may become attracted to the plastics in the ocean.

At this stage, we know that plastics and microplastics are ingested by marine life.  Estimates on historical data showed that plastics are predicted to be ingested by 90% of seabirds, globally (and estimated to reach 99% by 2050)[15].  Plastics have also been recorded in fish populations: at a rate of 35% on planktivorous species in the North Pacific[16]; at different frequencies in North Sea fish species[17]; and also in high frequencies in crustaceans such as Nephrops[18].  We therefore know the answer to the first part of point 1. (and we know that in some instances the direct physical effects can be damaging to marine wildlife such as whales[19]).  What we don’t know (at this stage) is the level of risk attached to the ingestion for the consumer of seafood products that may contain plastics or microplastics.

A large European project, the EC SafeSeafood project (described in the February 2017 Update[20]) described a stakeholder workshop attended by IFFO, and at which an extensive review of current risks to the seafood supply chain was discussed, including the topic of plastics and microplastics.  This was a reflection of the current state of knowledge in a large EU project, and the general consensus was that “levels of contaminants being identified are generally well below thresholds of concern for human safety”.  Despite some broad discussion on microplastics and some coverage of the science, no clear risks were highlighted.  There has been European funding of work on the subject since at least 2013[21] when the JPI Oceans projects were initiated.  Some of the science effort includes the feeding of farmed fish species (e.g. salmon) with microplastics to examine any effects, and so is directly relevant to the fishmeal industry (given a possible link between microplastics being found in pelagic fish species, and the likely carryover into fishmeal).

Some organisations have undertaken reviews of the science but again this is at an early stage.  One of the most comprehensive reviews of microplastics was the GESAMP Report No.90[22], published in 2015.  GESAMP is an advisory body consisting of specialized experts nominated by the Sponsoring Agencies (IMO, FAO, UNESCO-IOC, UNIDO, WMO, IAEA, UN, UNEP, UNDP).  Its principal task is to provide scientific advice concerning the prevention, reduction and control of the degradation of the marine environment to the Sponsoring Agencies.  One of the key conclusions from the GESAMP report in connection to commercial fish species and aquaculture was that “It is possible that microplastics may increase the chemical contamination of seafood, but there is little evidence to suggest that this represents a significant increase in risk to human health at the current observed microplastic concentrations”.  Despite the effort in that and other reveiws, communications highlight the same point – “Actual hazard potential still largely unknown”[23] (in Eurofish magazine in 2016).

Summary

The issue is of direct relevance to the fishmeal industry, given the potential link between ingestion of plastics by the fish species that are used for fishmeal production, and the possibility of transfer in the production process from both whole fish and byproduct material.  In general, the topic is highlighted in contemporary media, and is receiving attention in scientific research, although fishmeal is largely overlooked in these broader reports.  We can assume that funding for more science will be forthcoming in the short-term.  Although the current level of knowledge is relatively low, we may expect that the science will move forward quickly given increasing levels of funding and interest from numerous groups.  IFFO will maintain a watching brief on this subject.  In the meantime, members should also maintain an awareness of how important plastics may be within the context of their own production units, and continue to take steps to exclude any foreign material (including plastics) in their production processes.