Résumé: Gelatinous zooplankton, including cnidarians, ctenophores, and tunicates (appendicularians, pyrosomes, salps and doliolids), are often overlooked by scientific studies, ecosystem assessments and at a management level. Despite the important economic consequences that they can have on human activities and on the marine food web, arguments often related to the costs of monitoring or their coordination, or simply negligence, have resulted in the absence of relevant monitoring programs. A cost-effective protocol has been applied on trawling from existing fishery surveys conducted by national laboratories in England and France. The testing phase has successfully demonstrated the adequacy of such a tool to sample macro- and mega-zooplankton gelatinous organisms in a cost-effective way. This success has led to the acceptance of this protocol into the French implementation of the EU's Marine Strategy Framework Directive (MSFD). Here, a protocol which can be applied to any trawl-based fishery survey and in any new large-scale monitoring program is provided. As an ecosystem approach to marine management is currently adopted, exemplified by the MSFD in Europe, gelatinous zoo plankton should be monitored correctly to prevent a knowledge gap and bias to ecosystem assessments in future.

Résumé: The French initial assessment of the Marine Strategy Framework Directive (MSFD) highlighted the lack of reliable data concerning offshore areas. During the planning of the monitoring programmes, the scientists therefore proposed to partially cover this gap by using existing fisheries research vessel surveys deployed for the purposes of the Common Fisheries Policy (CFP). This paper describes ways of improving the effectiveness of these surveys and making them better suited to delivering the information needed for the MSFD. The process took two years and became operational at the beginning of the year 2016. Testing phases from October 2013 to August 2015 had to be organized to fit within the ongoing fisheries tasks without significantly increasing the workload in terms of both time and human resources. Six fisheries research surveys henceforth collect new data, with or without additional sampling techniques. Specific examples are given with litter and hydrological data which will be used to assess the environmental status of French marine waters. The paper also identifies certain limitations regarding this approach. This French experiment enabled more efficient and effective use of current data collection efforts, while optimising vessel time and implementing an ecosystem approach in collecting data for fisheries management.

Résumé: Trail-based ecology has been developed for decades lo infer ecosystem responses to stressors based on the functional structure of communities, yet its value in species-poor systems is largely unknown. Here, we used an extensive clataset in a Spanish region highly prone to non-native fish invasions (15 catchments, N 389 sites) to assess for the first time how species-poor communities respond to large-scale environmental gradients using a taxonomic and functional trait-based approach in riverine fish. We examined total species richness and three functional trait-based indices available when many sites have <= 3 species (specialization, FSpe; onginaliy, FOri and entropy, FEnt). We assessed the responses of these taxonomic and functional indices along gradients of altitude, water pollution, physical habitat degradation and non-native fish biomass. Whilst species richness was relatively sensitive to spatial effects, functional diversity indices were responsive across natural and anthropogenic gradients. All four diversity measures declined with altitude but this decline was modulated by physical habitat degradation (richness, FSpe and FEnt) and the non-native total fish biomass ratio (FSpe and FOri) in ways that varied between indices. Furthermore, FSpe and FOri were significantly correlated with Total Nitrogen. Non-native fish were a major component of the taxonomic and functional structure of fish communities, raising concerns about potential misdiagnosis between invaded and environmentally-degraded river reaches. Such misdiagnosis was evident in a regional fish index widely used in official monitoring programs. We recommend the application of FSpe and FOri to extensive clatasets from monitoring programs in order to generate valuable cross-system information about the impacts of non-native species and habitat degradation, even in species-poor systems. Scoring non-native species apart from habitat degradation in the indices used to determine ecosystem health is essential to develop better management strategies. (C) 2013 Elsevier B.V. All rights reserved.