European Red List of Marine Fishes

Marine conservation is a challenging issue due to conflicting interests, system complexity and limited knowledge. The production of Red Lists is considered as an essential tool for assessing priorities in the protection of marine habitats and species, aiming for a balanced marine governance. Most marine habitats are dominated by fishes; therefore, a Red List of marine fishes is of special interest for marine conservation policies. After several regional Red Lists in various European countries were produced in recent years, the first approach to a European Red List of marine fishes has been published by the European Union. This project is highly ambitious, assessing no fewer than 1220 fish species.

Sixty international authors contributed to this book. It contains a foreword written by Pia Bucella, the director of the Directorate B (Natural Capital) of the European Commission, explaining the role of European regional Red Lists in the context of the European legislation; the current Red List of marine fishes is filling a gap for the last group of vertebrates that still remained to be assessed. As stated in the acknowledgements section, the European Red List of Marine Fishes and consequently this report were requirements of a service contract with the European Commission.

The book is structured in five chapters. The introductory chapter explains the background, including the European context, where the area assessment boundaries are delineated. The European seas reach from the White Sea and parts of the Arctic Ocean east to Novaya Zemlya (Russian Federation), including Spitsbergen, and stretching west to Iceland (but not Greenland). The region covers the northeastern Atlantic Ocean south to the Canary Islands and west to the Azores (but excluding the coasts of Morocco and Western Sahara), the complete North Sea and Baltic Sea, the Mediterranean and Black Seas and the Sea of Azov. Not included are the Caspian Sea and overseas marine territories of the European Union. In the following discussion on the diversity and endemism of European fishes, it is stressed that the assessment follows the 1996 update of the list of the Fishes of the Northeastern Atlantic and Mediterranean which was published by Whitehead et al. in 1986, excluding species which were considered to be either Lessepsian migrants immigrating from the Red Sea through the Suez Canal, and also excluding eastern Atlantic species that recently dispersed into European waters, possibly due to warming sea surface temperatures.

Of the 1256 species listed by Whitehead et al. (1984–1986), a total of 1220 marine fish species considered to be native were extracted and assessed. In addition to these considerations, the economic value of European marine fish species is briefly discussed, and the assessment criteria of species extinction risk are explained to follow IUCN criteria and Red List categories, with exceptions and methods used for species with poor data or exploited species which are managed by fisheries policies. Finally, the objectives of European Red List assessment are summarized and include (1) a contribution to regional conservation planning, (2) the identification of priority geographic areas and habitats needing to be conserved to prevent extinctions, (3) the identification of major threats and the proposal of potential mitigating measures and conservation actions to address them, and (4) to strengthen the network of experts focused on marine fish conservation in Europe. The European Red List of marine fishes is supplemented by a freely available database holding the status and distribution of European marine fishes (European Red List 2015) and a website and data portal (IUCN Red List of Threatened Species 2015) presenting these data for the assessed species in the form of fact sheets. The second chapter gives a very brief outline of the methodology, the geographic range, the taxonomic scope, the assessment protocol and the species mapping. The main new information is that the assessment project lasted three years, and that several expert and IUCN workshops were held to assess European marine fish species. Species treated in the previous European Red List of freshwater fishes by Freyhof & Brooks (2011) are not assessed again in the marine list; this includes important species such as the European eel Anguilla anguilla (Linnaeus, 1758) (family Anguillidae) or the plaice Pleuronectes platessa Linnaeus, 1758 (Pleuronectidae).

The results are summarized in Chapter 3. None of the species is considered as ‘Extinct’, ‘Extinct in the Wild’ or ‘Regionally Extinct’; a total of 59 species (4.8% of the assessed species) are either ‘Critically Endangered’, ‘Endangered’ or ‘Vulnerable,’ including eight species endemic to European oceanic waters. An additional 26 species are ‘Near Threatened’ and 209 species (17.1%) are ‘Data Deficient’; the remainder of the species are of ‘Least Concern’. Not surprisingly, all the Critically Endangered species are chondrichthyans. The status of European chondrichthyans (sharks, rays and chimaeras) is further discussed in a separate section, as is the status of the European salmon (Salmo salar Linnaeus, 1758). Statistics evaluate the distribution of species in European seas (with the highest species diversity from the Canary Islands), the distribution of endemic species (most are found in the northern Mediterranean), and the number of threatened as well as data deficient species (again most in the Mediterranean Sea and the Canary Islands). Major threats to European fish species are briefly discussed; the most important threats include fisheries for target species, or the by-catch of such fisheries, and unknown threats. Other threats are either not affecting many species, or their impact on fish species is unknown. Very serious gaps in knowledge are admitted; these remain in the understanding of the distribution, population size, population trajectory and biology of many marine fishes, including many commercially important species.

Chapter 4 provides an overview of potential conservation measures. It mainly lists various international conventions aimed at marine conservation, a very brief discussion of relevant fisheries policies, and a mention of the NATURA 2000 network of Marine Protected Areas. It is stressed that a high Red List ranking does not necessarily imply a high priority of conservation action, as the setting of conservation priorities also needs to take into account various other factors, from ecological and economical to the availability of funds and personnel, and legal frameworks for conservation of taxa. Nevertheless, in Chapter 5 a number of recommendations for the conservation of European marine fishes are proposed, including additional research and data collection, the enforcement of existing European legislation, a restriction of fisheries in all designated Marine Protected Areas of the NATURA 2000 network, and the revision of the European Red List of marine fishes on a regular basis. After a references section, Appendix 1 (which is the main part of the book) provides a list of all assessed marine fish species and their Red List status, and in Appendix 2 a sample fact sheet and distribution map of the Halibut Reinhardtius hippoglossoides (Walbaum, 1792) (family Pleuronectidae) is presented, which is classified as Near Threatened.

In marine habitats, IUCN Red List criteria are generally difficult to apply. They originally targeted terrestrial species such as birds, where individuals, nests and eggs can be counted by visual observation, and they require detailed information on population size, size of the distribution area and population trends. In the ocean, such criteria are difficult to research. In many habitats, species can hardly be observed, but must be removed by commercial or research fisheries to get an estimate of their population size. Fishing efficacy of different types of gear has to be taken into account; a fish that is difficult to collect with standardized gear cannot be easily assessed. Marine habitats are often patchy and extremely heterogeneous. Even a widespread species may only be present in a certain, narrow depth range, and in a few patches, each harbouring a ‘micropopulation’. What is then the size of the distribution area – the whole area in the distribution map, or the added areas of the distribution patches? Also, what defines a population of sedentary species with pelagic eggs and larvae, where the adults are stationary, but the young are mobile, and the whole population system is connected by circular currents?

As stated above, our knowledge of the biology of many marine fish species in European waters is poor. Therefore, to apply IUCN criteria to marine fishes, much guesswork is needed. Alternatively, a large percentage of fish species must be classified as Data Deficient, and consequently cannot be assessed. Some previous Red Lists, for instance early OSPAR and HELCOM lists, have used different sets of criteria in addition to the IUCN criteria and are modified for their application to marine species to overcome these obstacles and get a more realistic picture of threatened and declining species. European Red Lists, however, use IUCN criteria as their only standard. Roughly one fifth of the species is treated as Data Deficient, and more such Data Deficient species may be hiding among the 70.7% of the species categorized under Least Concern. The percentage of threatened and declining species therefore seems to be underestimated in the European Red List of marine fishes.

A significant strength of the book lies in the classification of the species that could be assessed according to IUCN criteria. It is important to know that many chondrichthyan species throughout European marine waters are Critically Endangered, Endangered or Vulnerable, and that for the time being no marine species is supposed to be either extinct or regionally extinct. For these species, well-documented species data sheets exist. Unfortunately, they are not part of the book (except the sample data sheet of a species classified as Near Threatened which is mentioned above), but have to be consulted in a separate, freely available database on the internet. The main Red List merely presents a list of species names in a category, as well as additional information on whether these species are endemic to European waters or not. If the reader wants to know the rationale for the Red List classification of fish species, he or she needs an additional search in the database. The fact sheets are relatively detailed for fishes in the marine list, but rather brief and not very informative for species categorized in the freshwater fish list. No references to regional or national Red Lists of marine fishes are included in these fact sheets.

Many fish species are euryhaline, and do not live exclusively in salt water, but also in brackish water and sometimes even freshwater habitats. The dominating oceanographic elements of two major ocean systems in European seas, the Baltic Sea and the Black Sea/Sea of Azov complex, consist of large brackish water masses with a gradient between salt water and fresh water; similar gradients are found in tidal sections of river mouths throughout the region. In the legislative context, brackish waters are usually treated as part of the ocean, not as part of the inland waters. For a complete picture of threatened and declining species in the Baltic Sea, we need to consider marine, brackish and freshwater species. In the European Red Lists for fishes, the boundary between marine and freshwater habitats has not been defined. The freshwater fish list was published first (Freyhof & Brooks 2011); it included assessments for many of those marine or brackish water species that enter fresh water at times, as well as most migratory species which spend much of their life in marine habitats, like the European sturgeon Acipenser sturio Linnaeus, 1758 or the European eel Anguilla anguilla, both classified as Critically Endangered. As mentioned before, the authors of the European Red List of marine fishes did not re-assess species previously treated in the freshwater list, but excluded them from their assessment. Many species from the Baltic Sea and Black Sea/Sea of Azov are not included in this Red List; and in the discussion and statistics, they have been excluded (or forgotten). In Table 5, which summarizes the Red List status of European marine fishes, Acipenseriformes do not appear at all, although the Critically Endangered A. sturio spends nearly all of its life in the European Atlantic. For instance, only 45 species of Anguilliformes are recognized, all of them either classified as Least Concern or Data Deficient, ignoring the enigmatic, Critically Endangered species A. anguilla. In the analysis of European marine regions, the Baltic Sea and Black Sea/Sea of Azov are insufficiently represented. Species numbers are underestimated, including total species diversity, endemic marine species, threatened marine fishes and data deficient marine fishes. This is a major conceptual problem, as such an analysis of the Baltic Sea or the Black Sea/Sea of Azov is also not included in the European Red List of freshwater fishes, which exclusively focuses on inland waters.

Several species of European marine fishes were formerly divided into subspecies. This is not useful for conservation purposes, as each taxon of the species group needs to be assessed separately in Red Lists. Some species checklists, however, do not consider individual subspecies, but merely list the ‘parent’ species. This is the case for the online Catalog of Fishes (Eschmeyer 2015), on which the classification of the European Red List of marine species is based. The Catalog treats subspecies as synonyms of the ‘parent’ species, with the remark that valid subspecies have been recognized by authors. In their checklist and Red List of the fishes of Turkey, Fricke et al. (2007) raised all subspecies of European marine fishes occurring in the Mediterranean and Black Sea to the species level, so that conservation issues could be adequately addressed. This was subsequently followed by many authors. The online Catalog of Fishes is not yet fully revised in this respect. Some species have already been raised to the species level, while others are still treated as synonyms of the ‘parent’ species, though as valid subspecies. This was obviously not checked for the European Red List of marine fishes, and errors occurring in the Catalog of Fishes were repeated, not corrected. For instance, Tripterygion minor (Kolombatovic, 1892) (family Tripterygiidae) was treated as a valid subspecies of T. melanurum Guichenot, 1850 by earlier authors, but as a valid species by most recent authors; yet the taxon is not assessed in the European Red List. Former subspecies of Diplodus sargus (Linnaeus, 1758) (family Sparidae) and Diplecogaster bimaculata (Bonnaterre, 1788) (family Gobiesocidae) are missing as well; the assessments of the ‘parent’ species in their entire distribution range, where all former subspecies are lumped together, is inadequate and misleading.

Furthermore, some species of eastern Atlantic origin recently recorded from the Mediterranean were excluded from the assessment as so-called ‘vagrant’ and non-native species. While such immigration may be linked to global warming, their exclusion seems barely justified. Such immigrants usually enter the Mediterranean through the Strait of Gibraltar and then follow the North African coast, where the fish fauna is not well known, and are then first recorded from Israel, Turkey or Greece. An immigration of single individuals over such a long distance is not probable, at least for benthic species with a short-lived larval stage. It is suspected that populations have already been established, but are not yet known to science. An assessment with a probable resulting classification as Data Deficient would be more adequate in such cases.

The style of the book follows the standardized scheme of previous European Red Lists. It is easy to read, does not provide much detail, but just gives a brief summary of the most important facts. The main bulk of the text is a mere list of the assessed species in Appendix 1. The important Chapters 4 (Conservation measures, 2 pages) and 5 (Recommendations, 3 pages) are rather short, though the latter includes some important items. It is certainly a good idea to restrict fisheries in all designated Marine Protected Areas and to fully adopt and enforce such fisheries management measures. How could a benthic marine fauna ever be efficiently protected if trawl fisheries are ploughing through the benthic habitats every few weeks? There is still a long way to go in order to achieve a sound European marine conservation scheme, but in spite of their brevity these recommendations are certainly strengths of the book.

Another topic recurring in the book is the need for more scientific knowledge. This is emphasized in the discussion and also in the recommendations. The numerous Data Deficient species, the poor knowledge of the biology, reproduction, population size and dynamics, and even the systematic identity and distribution of some species highlight the importance of additional funding of scientific research. The paucity of European taxonomists is another obstacle; how can we achieve insights into the biology if we cannot even properly distinguish and identify the species?

In summary, the book falls short of its aim to present the actual knowledge on European threatened and endangered marine fish species. Many taxa were either excluded from the assessment and discussion, or were missed out for other reasons, and the treatment of some regions like the Baltic Sea and the Black Sea/Sea of Azov is inadequate. This book can only be considered as the Red List for a choice of European marine fish species; yet, it is an accomplishment that it has managed to assess a number of important marine fishes, identify many chondrichthyans as highly threatened and provide some important recommendations for marine conservation. It is a valuable book for anyone addressing biodiversity conservation and fisheries governance, and will necessarily be consulted by many readers in Europe and beyond, but although it has only just appeared there is already an urgent need for revision.