The biogeographic history of French freshwater fish is poorly defined, and fishery managers donot currently take into account the only functional level, that of genetic stocks. The aim of the present paper is to provide a contribution for filling this gap. It surveys existing knowledge and previous studies of the genus Barbus in France. A first part chronicles the populations of the two French species according to ancient (tertiary) and recent (pre- and post-glacial, and contemporary) history. Thus, the Barbus meridionalis lineage seems to have been present in this country for 5 million years at least (Upper Miocene), but the present populations of the Rhône Valley seem to be the result of recent recolonization by populations restricted to a Languedoc-Roussillon sanctuary during the glaciations. B. barbus has its origin in the Danube drainage basin. It is a more recent invader in Western Europe. Its immigration may have occurred during the Pliocene interconnections between the Rhône, the Rhine and the Danube basins (and perhaps even that of the Loire), or even more recently. If the first assumption is correct, the present populations of the Rhône are presumably descended from populations that found a shelter in the southern tributaries of the right bank of the river, or even in the tributaries of the right bank of the River Saône. In the Rhine basin, the sanctuarymay have been the tributaries of the left bank, the Meuse and the Mosel Rivers, from which probablydescend the populations of Eastern England. The present occurrence of B. barbus in the Garonne catchment and perhaps also the Seine catchment seems to be due to man. The second part of the paper considers the genetic point of view, but the lack of data make it possible to discuss only the status of B. meridionalis. A synthesis of the available enzymatic data, compared with the hypotheses expressed in the first part, reveals a good agreement between the two approaches. In particular, the French an Spanish populations are well differentiated from one another, confirming the ancient settlement of the species in these countries. Moreover, the homogeneity of the French populations, and the higher polymorphism of the Roussillon population, agree with the presumption of a survival in this province during the glaciations. For instance, the first results on B. barbus show a very low polymorphism and a very high homogeneity throughout the different catchments examined (Rhône, Meuse, Garonne, Hérault). Based on this work, a historical diagram is proposed, with the aim of ordinating the hypotheses for future research on the genetics of this group.

In the Mediterranean Sea, the fish Sarpa salpa (Sparidae) is the only vertebrate grazer of Posidonia oceanica meadows. In order to gain knowledge about the behaviour of S. salpa and a better understanding of the meadow's primary production recycling, an original study was designed using ultrasonic telemetry to investigate activity patterns and space utilisation in the field. During June–September 2000, we compared diel movements of six adult S. salpa (249–317 mm FL and 313–633 g) in the Bay of Calvi. These fish were tagged by intraperitoneal insertion of ultrasonic transmitters. Their positions were recorded with a directional hydrophone from a small boat with an accuracy between 10 and 50 m, depending on the local environment. The tracking duration ranged from 3 to 22 days (average 11.8 ± 7.3). Locations were performed from at least dawn to dusk or early night, and one fish was tracked during the entire 24-h cycle. Fish were more mobile during the twilight periods, but statistical analysis indicated individual differences for the precise period of mobility. Two major behavioural patterns were observed: first, the fish remained in close vicinity of the harbour during the day and moved away to the north or the south at dusk to access nocturnal sites, occupying a home range of about 4.3 ha. The second behavioural pattern involved persistent occupation of the same sites during day and night within a relatively restricted home range (about 0.8 ha). Great variation in mobility was found and the same individual fish could show both kinds of behaviour.

Marine land-based fish farms located in coastal wetlands (salt-pond zones, lagoon banks, etc.), whether extensive or intensive, send farm effluents directly to the sea or after short periods of stocking in retention reservoirs. The aims of our investigation have been to compare the efficiency of current and potential water treatment procedures in open-air. Wastewater retention ponds in commercial farms (Atlantic coasts of France) are efficient in removing up to 1 metric ton of particulate material (dry weight) per hectare and per day (faeces and unconsumed feed), but are inefficient in reducing dissolved wastes, both organic (urea, amino acids, protein) and inorganic (total ammonia nitrogen, phosphates). Forthcoming outdoor technology to treat these forms of waste were examined by trials at different sites: treatment by foam fractionation in extensive systems (Italian fish pond culture), treatment by microalgae production (Skeletonema costatum) and oyster filtration (Crassostrea gigas) in intensive systems (sea bass farm, Dicentrarchus labrax). It can be concluded that foam fractionation coupled with aeration and water circulation is a good way to treat and recirculate wastewaters in extensive systems, but that a multiple treatment combining a retention pond, foam fractionation and microalgae-bivalve filtration, is the best solution to treat all these forms of wastes from intensive systems.

Most highly fecund marine fish show a steep decline in natural death rate from egg to first maturity, after which the natural mortality rate remains constant, or may even increase with age for old animals. Relatively few investigations have quantified early life-history mortality vectors for short-lived invertebrate stocks, but this overall picture is also true here for species with planktonic life stages such as penaeid shrimps, and for squids. If M decreases rapidly with age, one logical approach to demographic analysis is by subdividing the lifespan into intervals which increase in duration in proportion to the age up to the start of each interval. This time subdivision strategy is referred to as `gnomonic’. Earlier work (Caddy, 1990) showed that if a reciprocal mortality function applies with age, the product of the instantaneous annual rate of natural mortality and interval duration should be roughly constant for gnomonic intervals. This working hypothesis is shown to produce similar results to the reciprocal function for Mt, but allows a simpler approach to generating realistic life history Mt vectors in the absence of direct estimates of M for stock assessment. Values of a constant probability of death, G = Mt Δt, were used to generate vectors of M-at-age for a gnomonic series of intervals from hatching up to the mean parental age. The value of G is found by iteration that results in 2 survivors from the mean population fecundity by 1 year of age, under the assumption of steady-state population replacement for an unexploited stock. The natural mortality rate in the final, longest interval was assumed to correspond to the ‘constant adult M’ value used in stock assessment. Two extremes of reproductive strategy were chosen by comparison with data from for annual species of cephalopods or penaeid shrimps: cephalopods such as Sepia sp. and Rossia sp., with few, large yolky eggs (and/or parental care), occupy one extreme, and are contrasted with high fecundity penaeid shrimps and at least some Illex squids.

The first category has a low fecundity (130–150 eggs, and a K-selected reproductive strategy). Values of ‘adult M’ of the order of 1.0–1.3 are predicted for the last 60–80% of the annual life span. The high fecundity category (200 000 eggs or more) are opportunistic spawners such as many penaeids and some oceanic squids, and follow an r-selected reproductive strategy. An instantaneous value for pre-spawning M of the order of 2.8–3.4 is predicted for the same period mentioned above. Neither range of values falls outside those in the literature, for which a brief summary is presented.

An important research question relates to the order of magnitude of post-hatching mortality under population stability: it is suggested that irrespective of the specific model used for changes in M with age, this falls rapidly from an initial rate of some 50–75% per day for short-lived, high fecundity species in the 2 days following hatching, unless adult M values are much higher than above, and of the order of 25–40% for the low fecundity organisms over the same initial interval.

The diurnal vertical behaviour of yellowfin tuna observed from sonic tagging experiments in the western Indian Ocean (Comoros archipelago) is compared with the vertical profiles of temperature and dissolved oxygen concentration. Two different behavioural situations: off-FAD and FAD-associated yellowfin tuna, are characterized by the relationships between swimming depth and vertical structure of temperature and dissolved oxygen concentration (i.e.depth and thickness of the mixed layer, of the thermocline layer and of the oxycline) observed in the tracking area. Gradients of both paramelers are shown to be the key factors which determine the vertical swimming behaviour. From an analysis carried out on the whole oceanographic data set of the Western Indian Ocean, oxyeline is found to match with the depth of the 4.2-4.3 ml.1−1 dissolved oxygen concentration.

Vertical distributions of yellowfin tuna, for both off-FAD and FAD-associated situations, are modelled by using normal-derived distributions. These models indicate the probability of the presence of yellowfin tuna, related to the vertical profiles of temperature and dissolved oxygen concentration. A single mode distribution is fitted to describe the FAD-associated situation, and a bi-modal one for the off-FAD situation. Positions of the modes are determined by the relationship between the vertical swimming behaviour and the position of either maximum gradient of temperature or dissolved oxygen concentration. An iterative calculation of normal distribution standard error is conducted to adjust the shape of the eurve to cover the entire layer in which yellowfin tuna is considered to be present. Both models were applied in a remote area, east of the Seychelles, where purse seine catches are important. The predicted vertical distribution seems to be realistic and matches the observations given by echosound pictures of tuna schools obtained in the same area by purse seiners.

Statistical Process Control (SPC) methods are extensively used in manufacturing contexts to monitor production processes. This article illustrates their potential utility for monitoring the state of marine ecosystems, using survey indicators. We exemplify the use of one SPC tool, the cumulative sum (CUSUM) control chart, to detect persistent changes in the state of a system as new observations are collected, using simulated and real data. Practical guidelines are given on how the chart parameters can be tuned to achieve an acceptable compromise between the ability to detect anomalies quickly and keeping the risk of false alarms low. The common performance measures associated with control charts depend on some key assumptions being met, and the potential impact of their violation is indicated.

The most distinctive feature of the reproductive biology of Hoplosternum littorale is the building and guarding of an elaborate floating bubble nest. Reproduction starts at the age of one year. Males grow to a larger size than females and, during the breeding season, they develop fat deposits in the pectoral fin and an elongated recurved pectoral spine that often assumes a reddish colour. Analysis of gonadal development and surveys of nesting in swamps show that initiation of reproduction is associated with the onset of the rainy season. Males start building the nest at night, and spawning takes place around noon the day after. Most nests are built in newly flooded swamps, especially in open water in the peripheral area of the swamp. A minimum distance of 10 m between nests is usually observed. The floating bubble nest consists of a dome of plant material supported by oxygen-rich foam produced by the male. Diameter and height of the nest average 30 and 6 cm, respectively. The nest is the centre of a territory that is vigorously defended by the male, using its enlarged pectoral spine, against conspecific and heterospecific intruders. The number of nests that did not acquire spawns (48 %) suggests a bold competition among males for females. There are indications that the female drinks the sperm and that fertilization takes place after the sperm has passed through her digestive tract. Hoplosternum littorale is a multiple spawner. Investment in reproduction is high in females since they can spawn up to 14 times during a 7-month breeding season and each spawn consists of 6 000 to 9 000 eggs. On average, two to four females spawn simultaneously, resulting in an average number of 20 000 eggs per nest. Incubation of the eggs takes two to three days depending on the temperature in the nest. Despite intense predation pressure on eggs and larvae, the guarding behaviour of the male extends for only one or two days after hatching. In the hypoxic water of tropical swamps, the main function of the floating bubble nest appears to be to provide oxygen to the developing eggs by lifting the eggs above the water surface while protecting them from desiccation. Other functions of the nest may be protection of the brood against predators, temperature regulation, identification of the centre of the territory and synchronization of reproductive activities. We suggest that H. littorale may be a useful model for the study of the reproduction of tropical freshwater fish in hypoxic environments.

A population of the invasive slipper limpet (Crepidula fornicata) has been spreading in the Bay of Mont-Saint-Michel (Western English Channel) for 40 years. Sidescan sonar, underwater video and quantitative sampling were conducted in 1996 and 2004 to document the widening geographic spread of the species over the bay. The limpet population grew by 50% during this period, to reach a fresh biomass of about 150 000 t. This local study analyses causes and effects of the spread and provides a typical example of the limpet spreading process. This population increase has significant effects on the environment in the most densely colonized area (modification to the sediment and biodiversity), leading to the emergence of a new benthic community. Anthropic dredging activities are among the causative factors of the spread but are also adversely affected by the invasion.

Small-scale fishing produces about half of the total landings of the gulfof Gabès (Tunisia), but still remains very poorly known. Coastal fleet structureis studied through a typological approach based on multivariate analyses of tripcatches (principal component analysis, cluster analysis, and partition). Eleven‘métiers' are defined by combinations of target species,fishing gears and periods: two of them target cephalopods (octopus and cuttlefish) inwinter, one targets shrimp with trammels, and eight target finfish in a more or lessselective way with gillnets, trammelnets or their combination, with set nets,and with longlines. This study of Tunisian coastal fishery is the first step towardsa more thorough understanding of its structure and dynamics, which is necessary forthe management of resources and fishing activities.

Martinique is a French overseas department whose economy relies heavily on agriculture. Organochlorine pesticides, mainly chlordecone, were used for banana cultivation to eradicate banana weevil over a period of 40 years. Chlordecone is chemically stable,and has a strong affinity for fatty tissues. It is therefore able to bioaccumulate in animals and thereby represent a threat to ecosystems and man. Soils from banana plantations in Martinique are heavily contaminated with chlordecone. Possible transfer of these molecules from agricultural watersheds to the aquatic environment and the organisms that live in it is feared. The hypothesis that ecosystems of Martinique might be highly contaminated with this organochlorine pesticide was investigated. Chlordecone levels were measured in various freshwater and marine species. Data show a heavy contamination of many carnivorous and detritivorous species (fish and prawns). Concentrations measured in wild or farmed tilapia are among the highest ever reported in the literature. Some coastal species (fish and lobster) were also found to be contaminated, although to a lesser extent. Given the biogeochemical behavior of chlordecone, the most likely route of contamination is food. Detected concentrations in marine organisms are below the tolerated limits established by authorities, however, the impact of other sources of exposure, namely, contaminated water and root vegetables, remains to be investigated.

A lightweight sorting grid was developed to reduce bycatch in the Danish small-meshedtrawl fishery (22 mm full mesh in the cod end) for Norway pout in the North Sea.Experimental fishing with the grid demonstrated the possibility to capture Norway poutwith only a minimum of unintended bycatch. Fishing with two different grid orientations,backwards and forwards-leaning, in distinct day and night hauls, resulted in an estimatedrelease of between 88.4 and 100% of the total number of haddock (Melanogrammusaeglefinus) and whiting (Merlangius merlangus) entering thetrawl. However, bycatch reductions were not significantly different between day and nightor between grid orientations, indicating that the grid rejection of haddock and whiting isnot influenced by fish behaviour. The loss of the target species, Norway pout, was low(between 5.6% and 13.7%) in comparison with the bycatch excluded, and clearly lengthdependent. Consequently, loss of target species would vary with the size structure of thepopulation fished. Although results were not statistically significant, length-basedanalyses indicated that the grid rejection likelihood for particularly smaller Norway pout(<16 cm) was higher when fishing with the forwards-leaning grid during the night;this might be explained by behavioural and visual aspects of the fish-grid encounterprocess for Norway pout.

The ecosystem-based approach to fisheries management and, more specifically, the European Marine Strategy Framework Directive require the assessment of the state and dynamics of an ecosystem in order to determine suitable management strategies. This paper takes an analytical approach to assess the state of the Bay of Biscay ecosystem in the early 1990s, chosen as a period of reference because key monitoring data series have been collected since then. To assess the state of the ecosystem, the pressures exerted by six broad categories of human activities were examined. A literature review of the ecosystem components was made and a component tree was tailored according to data availability. Data rich components were subdivided into subcomponents for their assessment while data poor components were assessed at an aggregated level. The component tree of the ecosystem comprised six main branches, four of which further divided into sub-components. In total, assessments were carried out at the level of 19 components. For four of these (fished species, sensitive fish species, marine mammals and turtles) the overall assessments were made combining the status of individual species. Impact from human activities were categorised as (i) “widespread” over the whole Bay of Biscay or “local” and (ii) “possible” when they could be logically expected or “documented” when they were reported in the literature. Fishing appeared to be the only activity exerting widespread documented impacts on several ecosystem components. Terrestrial activities had some possible and documented widespread impacts. With the exception of marine transport impacting seabirds at the regional scale through oil pollution, other activities had only local impacts, mostly nearshore. The reference state in the early 1990s, suggests that continuation of monitoring of vertebrates as well as estuarine and coastal habitats must be central to the monitoring programme and management strategies to be set in the context of the Marine Strategy Framework Directive. Additional monitoring is also required for benthos, substrate and micro-organisms.

Pouting, Trisopterus luscus is harvested commercially on the Galician shelf by the Spanish inshore artisanal fleet. In spite of a substantial decrease in pouting catches, fishery regulations are limited to size length restrictions. This study provides biological data including length-at-maturity based on histological methods, seasonal maturation, spawning and fecundity. A collection 443 females, from 17 to 42 cm in total length, were sampled from landings (December 2003 to December 2004). Pouting length-at-maturity was estimated as 19.2 cm on average. Pouting females in spawning condition were observed throughout the year and the number of developing oocytes ranged from 20 000 to 1 327 000. Peak spawning was observed between February and April, which correlated well with trends in gonadosomatic index, and inverse to condition factor and hepatosomatic index. Histological examination of the gonads revealed that pouting ovarian development organization is asynchronous, and fecundity is probably determinate.

The present work is based on a set of bottom trawl surveys performed in the Gulf of Lions between 1983 and 1992. A new method which couples the STATIS multitable approach with the logic of correspondence analysis (CoA) is proposed to study the stability of spatial organization of demersal assemblages in terms of species composition. This CoA version of STATIS has provided a clear representation of the stable part of the spatial structure of the assemblages. In addition, it gave an insight into the interannual variations of the distribution of each population around the reference structure. Our results showed that the demersal assemblages of the Gulf of Lions exhibited bold spatial structuring, mainly orientated along a bathymetric gradient. This gradient is structured around three major regions: the coast, the continental shelf and the continental slope. Despite sampling variations that occurred during the course of the study, the analysis showed a high degree of reproducibility for this spatial pattern. With the exception of Mullus surmuletus, the species considered in this investigation exhibit limited variations in their spatial distribution. Finally, in the absence of log-books covering the activities of commercial fishing vessels, these findings constitute a base of reference for the analysis of the dynamics of fishing fleets exploiting the demersal resources of the Gulf of Lions.

Using experimental data and a model to predict size selection based on morphological data, we investigated size selection of redfish (Sebastes spp.) in the grid-based selection systems used in Northeast Atlantic trawls. We found that not all redfish make physical contact with the spacing between the bars in the sorting grids while they pass in the direction of the codend, and therefore the escapement of some undersized redfish depends on size selection in the codend. We estimate that most of the escapement in the combined selection system (consisting of a 55-mm grid and a diamond mesh codend) happens through the grid. We demonstrated that for one of the two grid systems investigated the increase in size selection obtained experimentally by increasing grid-bar spacing is well in line with what could be expected based on the morphology of redfish. However, the size selection observed experimentally was significantly lower than the size-selective potential of the grids estimated based on the morphology of redfish. By computer simulations, we show that a possible explanation for this difference could be that not all redfish that attempt to escape through the grid make their attempt with an optimal angle of attack.

This paper provides an overview of the progress Ifremer has made recently in fisheries acoustics and the study of small pelagic fish by: i) pushing observation frontiers using a range of platforms including an autonomous underwater vehicle, AUV, ii) developing measuring instruments and methods and iii) studying fish distributions. Presently, information from several frequencies of single-beam echosounders is routinely collected together with data from the ME70 multibeam echosounder. For onboard data acquisition control the HERMES software was developed. The new MOVIES 3D software includes modules for simultaneous realistic 3D visualisation and post-processing such as bottom detection, school extraction and calculation of descriptors and integration of all acoustic data. Several data analysis methods are being developed and some initial results are presented. Finally, results on the spatial distribution of small pelagic fish schools in the Bay of Biscay illustrate the role that acoustics can play, and are already playing, in the implementation of an ecosystem approach to fisheries.

In order to understand the morphological differences between four populations of genus Coilia (Teleostei: Clupeiforms) and identify them conveniently, truss network data were used to conduct multivariate analysis. Nineteen morphometric measurements were made for each individual. Burnaby's multivariate method was used to obtain size-adjusted shape data. The cluster analysis and discriminant analysis were used to discriminate among populations. The results indicated that 1) the four populations were clustered into three distinct groups; the first group included Changjiang C. mystus and Taihu C. ectenes, the second one included Zhujiang C. mystus, the last one included Changjiang C. ectenes, and 2) discriminant analysis with selected 4 morphological parameters showed that the identification accuracy was between 88% and 100%, and global identification accuracy was 95%. Our result showed that populations of different Coilia species living in geographic proximity to one another are more similar than conspecifics living farther apart. Separation and adaption are important to morphological difference. The taxonomy of genus Coilia should be reconsidered. This study also showed that the method to obtain size-adjusted data is important to acquire right conclusion.

This study assessed the Zanzibar sea cucumber fishery using a multidisciplinary approach. Data was collected by (i) interviewing various groups of actors in the fishery and reviewing management documentation and legislation, (ii) by monitoring catches and (iii) through a visual census of coastal sea cucumber populations in areas open and closed to fishing. The fishery showed clear signs of being unsustainable with high fishing effort, and weak formal and informal management institutions. The fishery operation was characterised by an intricate cross-scale structure with both fishers and sea cucumber products being transported across national borders. The visual census of commercial sea cucumber stocks at three sites open to fishing around Zanzibar showed low densities across the range of sea cucumber value groups including low value species. Furthermore, the diversity of commercial sea cucumber species was lower in fished reefs than on a protected reef. The poor status of the sea cucumber populations was confirmed by the perception of an overfished resource by the interviewed actors active in the fishery. This was also depicted by the paucity of high value species, and high representation of low value and newly commercialised species in fishers catch. We conclude that the current state of Zanzibar’s sea cucumber populations is compromising the fisheries self-replenishment and existence and that the fishery is in urgent need of a complete management reform.

In a multi-gear and multi-species artisanal fishery, the level of technical interactions (i.e. the competitive externalities resulting from a shared exploitation of common resources or fishing grounds) among various fishing units is high. Assessing these technical interactions is of great importance for fishery management, as any control applied to one fishing unit may have positive or negative effects on others. The magnitude and direction of these effects cannot be easily measured, unless all fishing units and species in the fishery are considered simultaneously. Technical interactions are particularly important in the complex artisanal fisheries of the English Channel. Using a bioeconomic model of the English Channel that incorporates all the major fishing units (the BECHAMEL model), we describe a method for measuring and classifying the technical interactions due to the competition for resource (stock externalities). The results are used to develop a typology of métiers and fleets based on their overall level of interaction for the resource. We also define fleets and métiers as structuring, dependent, intermediate or autonomous.

Research on the biology and ecology of cold-water corals (CWCs) is still in its infancy.The growth patterns of CWCs in their natural environments are poorly known. Growth rateinvestigations on these deep-sea reef builder species are needed to predict recovery timesfollowing damage to their ecosystems. This study investigates a new approach for analysingCWC growth rate, suitable for in situ application. Lopheliapertusa and Madrepora oculata (Scleractinian) were collectedfrom the Lacaze-Duthiers canyon in the northwestern Mediterranean Sea (520 m depth),marked and then either redeployed in situ for 6 months, or maintained inaquaria for growth rate comparison at a constant temperature of 13 °C, corresponding totheir habitat conditions. Two different types of staining (calcein and manganese) andthree different exposure times (30, 60 and 240 min) were tested. The results show thatcalcein offers rapid incorporation and easy detection, making it particularly suitable forskeletal growth rate investigations compared with other chemical staining. In situlinear polyp growth rates of 7.5 ± 1.2 mm y-1 and 3.5 ± 2.1 mmy-1 were measured in new polyps of L. pertusa and M.oculata, respectively. Those values were significantly higher in young polypsthan in older ones, where they decreased to 1.3 ± 1.5 mm y-1 and 1.2 ± 1.2 mmy-1. Beyond the study of coral reef growth processes, this approach offers amethodological basis for habitat quality assessment which could be used in the managementof deep-sea marine protected areas (MPA).