MarBEF investigates the biodiversity of fish

Brian MacKenzie

Danish Institute for Fisheries Research, Kavalergården 6, DK-2920 Charlottenlund, Denmark

Figure 1. Slope fishes in deepwater corals at 800 to 900 m, south-west of Ireland. From top: Phycis blennoides, a gadoid species landed as by-catch on the offshore shelf and upper slope; Trachyscorpia cristulata echinata a scorpaenid fish by-catch of deepwater fisheries; a monkfish (Lophius sp.; these species are highly valued fishes throughout European waters which are heavily exploited on shelf areas and found down to 1000 m); Lepidion eques, a small morid species abundant on all slope areas from 500 m to 1500 m in the North East Atlantic, discarded by fisheries (©Ifremer, Caracole cruise, August 2001)

Figure 2. A fish market in Copenhagen showing some of the species of fish local consumers can buy. Will they have the same kind of fish to choose from in the future? Photograph credit: Brian MacKenzie

European seas have 100s of species of fish (Figure 1), and fish are one of the commonest marine animals encountered by Europeans. We see them in fish markets (Figure 2), restaurants, pet stores, and aquaria, and many of us devote entire weekends and vacations trying to catch or observe them in the sea. Fish also provide 1000s of jobs for Europeans either directly for fishermen or indirectly (e. g. processing, transport, tourism, research).

The different kinds of fish occupy a wide range of habitats characterised by differences in biotic and abiotic conditions such as the availability of food, presence of predators, temperature, salinity, oxygen concentration and light intensity. It is not surprising therefore that fish distributions can change over time and space, and that fish have specialised functional roles (e.g. as predators of certain types of zooplankton or of other fish) within marine ecosystems, or that distributions and functional roles change as fish grow.

Increasingly, however, we are seeing that many human-related factors are affecting fish distributions and therefore the biodiversity and functionality of local fish faunas. These factors include high fishing rates, eutrophication and structural changes to fish habitats (e.g. dredging). This means that the biodiversity of present and future fish communities is changing and may be quite different from what it was many years ago (i.e. before humans began to impact marine ecosystems). Society, including scientists and conservation organisations, is recognising that many of these changes are for the worse and is now considering ways to slow down and perhaps even reverse the changes.

MARBEF will be considering some of these issues as part of its activities. At the Bruges Kick-off meeting (March 17-19, 2004), the topic "fish and fisheries" was identified as a cross-cutting subject within MARBEF, having elements addressing several key actions and main themes of MARBEF.

A workshop was organised at IFREMER (Brest, France) from June 14-16 2004 to define a responsive mode project addressing biodiversity of fish, including effects of fisheries. The general aim of the project will be to address the following issues:

• fish biodiversity within EU waters (temporal/spatial variability, functioning) ;
• threats to fish biodiversity (direct impact from fisheries, other local anthropogenic impacts, global change, methods to stop fish biodiversity losses);
• genetic diversity of EU fish populations
• fish biodiversity and human society (e.g., impacts of different conservation measures on stakeholders).

The project will be designed to extend the activities of various recent and ongoing EU and national projects and to promote new approaches for biodiversity research within the fields of fish and fisheries ecology.