The idea that marine fish species should be managed at some sub-specific level can be traced to the early 20th century when two pioneering fishery biologists, F. Heincke and J. Hjort, established the local self-sustaining population as opposed to typological species as the preferred unit of study for fisheries management¹. Three primary drivers demand information at such scales, each incorporated within objectives of the EU Common Fisheries Policy (CFP). First, it is generally recognised that populations (hereafter used interchangeably with the term "sub-populations") are the natural unit of evolutionary change, and as such, provide the genetic resources required for adaptive response to natural and man-made changes in the environment. It is therefore at the level of populations that genetic and ecological diversity should be described for conservation measures, which necessitates discrimination between populations and their distribution and abundance across regional waters. Second, it is at the population level that policy legislation and associated enforcement must take place. In addition to output management tools (catch limits, TACs, minimum landing sizes) there is a growing need to develop control through input management tools (capacity and effort limitation)². Such a policy requires information on the relative dynamics and abundance of fish stocks from particular regions. Third, there is an increasing requirement for traceability of fish and fish products, both for consumer protection and for regulatory enforcement, in particular with respect to illegal, unreported and unregulated (IUU) fishing³. For example, in the UK, the Marine Stewardship Council encourages consumers to eat particular landings of cod that are taken from "stocks maintained within safe limits". A traceability system based on regional stocks is necessary to preclude fraudulent allocations.
Despite the long-term notion of sub-specific fishery units and plethora of phenotypic and genetic data4, effective incorporation of such thinking into fisheries management remains impeded5. Discriminating between marine fish populations is often problematic, and owing to low levels of differentiation and high variance in phenotypic characters, there is no single coordinated database to allow collation of information on population boundaries and dynamics of populations.
Moreover, globalisation has had major impacts on the food supply chain. It has removed production from direct consumer control, increased competition, lengthened the food supply chain, and made it less transparent. There has been an associated increase in awareness in traceability issues to deal with food safety, quality assurance and animal welfare. IUU fishing is a serious global problem and one of the main impediments to the achievement of sustainable world fisheries.
Worth between $4bn and $9bn per year, IUU fishing leads to major revenue losses (source: Energy, Environment and Development Programme of Chatham House in London). To reduce the market for illegal catches it is therefore necessary to develop an effective traceability system to verify the origins of fish caught.
Traceability is defined by the EU (EU Regulation on the General Principles and Requirement of Food Law Regulation6 as "the ability to trace and follow a food, feed, food-producing animal or substance intended to be, or expected to be, incorporated into a food or feed, through all stages of production, processing and distribution". There is an urgent need to identify traceability markers that can be used throughout the food supply chain, from on-board samples, to processed product ("fish to fork"), and which exhibit minimal variance. Furthermore, it is essential that such tools are validated to internationally recognised forensic standards. Only under such stringent conditions can traceability data be used for legal enforcement and as evidence in a court of law.
The underlying rationale of FishPopTrace is to assess and address challenges arising from the development of traceability tools within a forensic framework for four judiciously chosen target species: cod (Gadus morhua), hake (Merluccius merluccius), herring (Clupea harengus) and sole (Solea solea). While current information on levels of population structuring in traits such as life histories, morphometrics, genetics and physiology is used to inform sample choice, new data are restricted to markers at two levels: (1) Routine screening: selection of markers that exhibit maximal discriminatory power to identify populations, though with discrete and controlled variance enabling validation (single nucleotide polymorphisms (SNPs) and otolith microchemistry and morphometrics). Data from DNA-based methods provide a mechanism for traceability throughout the food supply chain ("fish to fork") and indicate discrete spawning populations, whereas otoliths provide an independent on-board traceability system of fish provenance. (2) Testing of novel tools: additional tools are tested on a selection of populations to assess validity and potential for traceability and validation, including fatty acid analysis, proteomics, gene expression analysis and the generation of high-throughput microarray platforms for SNP genotyping. Thus, FishPopTrace provides information that relates to geography ("population tag"), as well as providing regional signatures that indicate biological differentiation in relation to spawning identity. Both aspects are important for traceability, and are not mutually exclusive, since the former signals source of origin, whereas the latter yields information on biological variability that may underlie population resilience and evolutionary potential7. Recognising spawning groups therefore provides a base-line for conservation of genetic resources. Although there have been numerous definitions for the term "stock"8, hereafter we refer to "population" (=sub-populations) as a spawning assemblage, though for traceability purposes, regional identity that may, or may, not coincide with spawning groups and associated biological differentiation, is also a valid unit of recognition.
1 Sinclair, M (1988), Marine Populations. An essay on population regulation and speciation (University of Washington Press).
2 C.E.C., (2006) COM 499, final 1-12.
3 Gallic, BL, Cox, A, (2006) Mar. Pol. 30, 689-695.
4 Cadrin, X et al., (2005) Stock Identification Methods − Application in Fisheries Science (Elsevier Academic Press).
5 Hammer, C, Zimmermann, C, (2005) in Stock Identification Methods (Elsevier Academic Press).
6 European-Council, (2002) OJ L 358, 59-80.
7 Ruzzante, DE et al., (2006) P R Soc B 273, 1459-1464.
8 Carvalho, GR, Hauser, L, (1994) Rev Fish Biol Fish 4, 326-350.