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Papers by Patrick Astruch

Research paper thumbnail of Functional differences between fish communities on artificial and natural reefs: a case study along the French Catalan coast

Aquatic Biology, 2014

ABSTRACT In the context of growing anthropogenic disturbances that deeply alter marine coastal ec... more ABSTRACT In the context of growing anthropogenic disturbances that deeply alter marine coastal ecosystems, various management tools are used to protect biodiversity, such as fishing gear limitations, fishing quotas, protected areas or the creation of artificial reefs (ARs). In contrast to the other management tools, ARs require a modification of natural habitats. We used under - water visual censuses to investigate the effect of habitat modification on the structure of fish communities by comparing a natural reef (NR) to ARs with different habitat complexity. Different fish assemblage descriptors were used to assess species- and functional- and community-level aspects of the assemblages. ARs were rapidly colonized by adult fishes and presented community compositions different from that of the NR. Fish densities and functional richness were higher in the ARs than in the NR. Small isolated artificial structures, such as culverts and box-culverts, had different fish community compositions than more extended and complex structures, demonstrating the effect of structural habitat complexity on fish assemblages. Fish density was higher in small structures, most likely due to habitat isolation and patchiness. This study indicates that ARs which are located along sandy coastal areas with few rocky habitats and under high river nutrient influence are a suitable habitat for rocky coastal fish communities. Nevertheless, due to higher habitat complexity and lower fishing pressure on ARs, fish communities of an AR functionally differ from those of a NR. Further research is necessary to understand how these differences act on the properties of the ecosystem as well as on local fisheries.

Research paper thumbnail of How to enhance coastal sparids biomass? Patterns and kinetic of colonization by fish from a seasonal monitoring of 6 reef types in Marseille Prado reef area

Coastal fish populations are mainly shaped by habitat structure. The deployment of 27 300 m 3 of ... more Coastal fish populations are mainly shaped by habitat structure. The deployment of 27 300 m 3 of artificial reefs (ARs) in Marseille Prado Bay (Mediterranean Sea, Provence, France) offers the opportunity to compare the biological efficiency of 6 different types of ARs deployed at the same site, in large numbers. The Prado ARs were designed to favour species diversity by (i) diversifying the types of structure (shape, size and construction materials, and adding complexity with biogenic material input -first level of complexity), (ii) grouping and spatially arranging the modules -second level of complexity and (iii) creating biological corridors from natural habitats to ARs and between reefs. The numerous temporal replicates performed during 22 seasons under the same environmental conditions indicated that the fish communities of the different types of ARs did not vary in the same way according to seasons and did not present the same patterns of change in colonization scenarios. Differences in fish populations were evidenced between the 6 types of reefs. The specific composition, density and biomass significantly differed among reef types and presented a high temporal variability. The influence of size, structures' design, materials and volume of filling materials differed according to AR type, but fishing target species were overall increasing in density or/and mean size. The main criteria chosen for the deployment of the ARs (different volumes, adding complexity and arrangement of reefs relative to each other) can explain the success of this ARs deployment.

Research paper thumbnail of Les aménagements côtiers : de bons récifs artificiels ? Cas des zones portuaires de la région marseillaise

Despite their number and the surface area that small harbours cover along the French Mediterranea... more Despite their number and the surface area that small harbours cover along the French Mediterranean coast, few studies have been dedicated to their fish populations. Along the rocky coast of Provence, these harbours were generally built in small bays or coves, which are natural nursery sites for juveniles of many coastal fish species, in particular sparids and labrids. On the Western coast of Languedoc, striped bass (Dicentrarchus labrax) nurseries are localized in marinas as well as in estuaries and coastal lagoons.

Research paper thumbnail of Premier recensement du mérou brun (Epinephelus marginatus) à Porquerolles (Méditerranée, France)

Research paper thumbnail of CONTRIBUTION OF SMALL MEDITERRANEAN HARBOURS TO COASTAL FISH BIODIVERSITY

Despite their number and the surface area that small harbours cover along the French Mediterranea... more Despite their number and the surface area that small harbours cover along the French Mediterranean coast, few studies have been dedicated to their fish populations. Along the rocky coast of Provence, these harbours were generally built in small bays or coves, which are natural nursery sites for juveniles of many coastal fish species, in particular sparids and labrids. On the Western coast of Languedoc, striped bass (Dicentrarchus labrax) nurseries are localized in marinas as well as in estuaries and coastal lagoons.

Research paper thumbnail of Ecosystem-versus species-based approach of the human impact on the Mediterranean seagrass Posidonia oceanica

Biological indicators are largely used in the marine realm to (i) evaluate the quality of a water... more Biological indicators are largely used in the marine realm to (i) evaluate the quality of a water body, (ii) to weigh processes such as e.g. currents, sedimentation and climate under natural and anthropogenic forcing, and (iii) to monitor the status of species of interest, either emblematic species, indicators of ecosystem health or indicators of pollution. Sometimes, species used as biological indicators are key-species or ecosystem engineers. This is the case of the seagrass Posidonia oceanica.

Research paper thumbnail of Mapping and state of conservation of benthic marine habitats and assemblages of Port-Cros national Park (Provence, France, northwestern Mediterranean Sea). Sci. Rep. Port-Cros natl. Park, 26: 45-90

Cartographie et état de conservation des habitats et assemblages marins benthiques du Parc nation... more Cartographie et état de conservation des habitats et assemblages marins benthiques du Parc national de Port-Cros (Provence, France, Nord-Ouest de la Méditerranée). Les habitats et assemblages benthiques, ainsi que la bathymétrie, ont été cartographiés en 2010 au moyen d'un sondeur multifaisceaux interféromètre, d'un sonar latéral et d'orthophotographies, complétés par des observations en ROV (véhicule sousmarin télécommandé) et en plongée. La comparaison des données acquises en 2010 avec les cartes dressées dans les années 1960s-1970s, puis avec une carte levée en 1999, ainsi qu'avec l'ensemble des données disponibles sur Port-Cros, ne permet pas de conclure à une dégradation importante des habitats. La surface occupée par l'herbier à Posidonia oceanica n'a pas diminué et la vitalité de l'herbier est bonne à très bonne. Les grandes 'macroalgues' des Substrats durs infralittoraux à macroalgues photophiles et du Coralligène sont toujours présentes et abondantes. Le Détritique côtier se présente sous l'aspect qu'il avait peut-être en Méditerranée, avant que ses fragiles espèces calcifiées et concrétionnantes ne soient broyées par les chaluts. La gestion efficace de la pêche artisanale a permis de juxtaposer une pêche économiquement rentable avec des stocks élevés de téléostéens. En revanche, le récif-barrière de P. oceanica de la baie de Port-Cros continue à régresser ; la limite inférieure de l'herbier à P. oceanica remonte ; dans ce cas, la cause n'est pas à rechercher dans des impacts locaux, mais plus probablement dans des phénomènes climatiques. Des épisodes chauds, dont la fréquence s'accroit en -45 -liaison avec le réchauffement climatique, ont causé des mortalités massives d'espèces emblématiques, telles que les gorgones. Les forêts superficielles à Cystoseira brachycarpa var. balearica ont fortement régressé. Des 'macroalgues' introduites, envahissent la plupart des habitats ; leur impact sur la biodiversité, la structure et le fonctionnement des écosystèmes est encore mal connu. Cet impact peut s'accroître avec le temps, de telle sorte que, sur le long terme, il peut s'avérer dramatique. Au total, nos résultats traduisent d'une part le succès durable de la politique de protection du patrimoine naturel dans le Parc national de Port-Cros, mais aussi sa vulnérabilité à des impacts locaux ou venus d'ailleurs.

Research paper thumbnail of An Ecosystem-Based Approach to Assess the Status of a Mediterranean Ecosystem, the Posidonia oceanica Seagrass Meadow

Research paper thumbnail of Coastal man-made habitats: Potential nurseries for an exploited fish species, Diplodus sargus (Linnaeus, 1758)

Fisheries Research, 2013

Human pressure on seashores has induced the installation of many seawalls. Artificial coastal def... more Human pressure on seashores has induced the installation of many seawalls. Artificial coastal defence structures may be providential for the juveniles of fish species exploited by artisanal fisheries. Focusing on Diplodus sargus, the number of settling juveniles was estimated on artificial structures and on natural rocky shores. The aim is to know if these artificial areas can have a nursery function. Densities of juveniles are from 30 to 109 times greater than those in natural habitats. Artificial coastal defence structures can be regarded as artificial nurseries. However, in the studied case, they also cause the loss of the nursery function of the nearby lagoon. The artificial seawalls at the entrance to the lagoon receive almost all the larvae that would normally enter the lagoon. This study underlines the important role of these artificial habitats in the life cycle of white seabream. They may have a positive impact on maintaining other species exploited by artisanal fisheries.

Research paper thumbnail of Acoustic telemetry survey of the dusky grouper (Epinephelus marginatus) in the Marine Reserve of Cerbère-Banyuls: informations on the territoriality of this emblematic species

Comptes Rendus Biologies, 2009

The Marine Reserve of Cerbère-Banyuls represents a refuge for dusky grouper populations (Epinephe... more The Marine Reserve of Cerbère-Banyuls represents a refuge for dusky grouper populations (Epinephelus marginatus). Density survey and observation of the reproductive behavior of this species have been conducted there for the last 30 years. However, information on the behavior or habitat utilization for this species during winter time is limited. We conducted acoustic telemetry surveys from September 2005 to June 2006 in the Marine Reserve of Cerbère-Banyuls for a dusky grouper population. Six groupers were tagged and followed within the integral reserve and in the adjacent partial reserve. The results from the tracking of these individuals indicated that the largest dusky groupers are sedentary fishes with a high degree of site fidelity and a high sensitivity to variations of environmental conditions such as storms. This together with the life history characteristics of this species encourages the conservation and the protection of essential habitats of this species. Acoustic tracking coupled to the use of a fixed Kernel can be proposed to follow fish populations.

Research paper thumbnail of Evaluation of Artificial Reefs Impact on Artisanal Fisheries: Necessity of Complementary Approaches

Global Change: Mankind-Marine Environment Interactions, 2010

... Bayle-Sempere JT, Ramos-Espla AA, Charton JAG (1994) Intra-annual variability of an artificia... more ... Bayle-Sempere JT, Ramos-Espla AA, Charton JAG (1994) Intra-annual variability of an artificial reef fish assemblage in the marine reserve of Tabarca ... structure of fishes at artificial reefs off Southeastern Florida, USA Bull Mar Sci 55(2–3):796–823 Bombace G, Fabi G, Fiorentini ...

Research paper thumbnail of Functional differences between fish communities on artificial and natural reefs: a case study along the French Catalan coast

Aquatic Biology, 2014

ABSTRACT In the context of growing anthropogenic disturbances that deeply alter marine coastal ec... more ABSTRACT In the context of growing anthropogenic disturbances that deeply alter marine coastal ecosystems, various management tools are used to protect biodiversity, such as fishing gear limitations, fishing quotas, protected areas or the creation of artificial reefs (ARs). In contrast to the other management tools, ARs require a modification of natural habitats. We used under - water visual censuses to investigate the effect of habitat modification on the structure of fish communities by comparing a natural reef (NR) to ARs with different habitat complexity. Different fish assemblage descriptors were used to assess species- and functional- and community-level aspects of the assemblages. ARs were rapidly colonized by adult fishes and presented community compositions different from that of the NR. Fish densities and functional richness were higher in the ARs than in the NR. Small isolated artificial structures, such as culverts and box-culverts, had different fish community compositions than more extended and complex structures, demonstrating the effect of structural habitat complexity on fish assemblages. Fish density was higher in small structures, most likely due to habitat isolation and patchiness. This study indicates that ARs which are located along sandy coastal areas with few rocky habitats and under high river nutrient influence are a suitable habitat for rocky coastal fish communities. Nevertheless, due to higher habitat complexity and lower fishing pressure on ARs, fish communities of an AR functionally differ from those of a NR. Further research is necessary to understand how these differences act on the properties of the ecosystem as well as on local fisheries.

Research paper thumbnail of How to enhance coastal sparids biomass? Patterns and kinetic of colonization by fish from a seasonal monitoring of 6 reef types in Marseille Prado reef area

Coastal fish populations are mainly shaped by habitat structure. The deployment of 27 300 m 3 of ... more Coastal fish populations are mainly shaped by habitat structure. The deployment of 27 300 m 3 of artificial reefs (ARs) in Marseille Prado Bay (Mediterranean Sea, Provence, France) offers the opportunity to compare the biological efficiency of 6 different types of ARs deployed at the same site, in large numbers. The Prado ARs were designed to favour species diversity by (i) diversifying the types of structure (shape, size and construction materials, and adding complexity with biogenic material input -first level of complexity), (ii) grouping and spatially arranging the modules -second level of complexity and (iii) creating biological corridors from natural habitats to ARs and between reefs. The numerous temporal replicates performed during 22 seasons under the same environmental conditions indicated that the fish communities of the different types of ARs did not vary in the same way according to seasons and did not present the same patterns of change in colonization scenarios. Differences in fish populations were evidenced between the 6 types of reefs. The specific composition, density and biomass significantly differed among reef types and presented a high temporal variability. The influence of size, structures' design, materials and volume of filling materials differed according to AR type, but fishing target species were overall increasing in density or/and mean size. The main criteria chosen for the deployment of the ARs (different volumes, adding complexity and arrangement of reefs relative to each other) can explain the success of this ARs deployment.

Research paper thumbnail of Les aménagements côtiers : de bons récifs artificiels ? Cas des zones portuaires de la région marseillaise

Despite their number and the surface area that small harbours cover along the French Mediterranea... more Despite their number and the surface area that small harbours cover along the French Mediterranean coast, few studies have been dedicated to their fish populations. Along the rocky coast of Provence, these harbours were generally built in small bays or coves, which are natural nursery sites for juveniles of many coastal fish species, in particular sparids and labrids. On the Western coast of Languedoc, striped bass (Dicentrarchus labrax) nurseries are localized in marinas as well as in estuaries and coastal lagoons.

Research paper thumbnail of Premier recensement du mérou brun (Epinephelus marginatus) à Porquerolles (Méditerranée, France)

Research paper thumbnail of CONTRIBUTION OF SMALL MEDITERRANEAN HARBOURS TO COASTAL FISH BIODIVERSITY

Despite their number and the surface area that small harbours cover along the French Mediterranea... more Despite their number and the surface area that small harbours cover along the French Mediterranean coast, few studies have been dedicated to their fish populations. Along the rocky coast of Provence, these harbours were generally built in small bays or coves, which are natural nursery sites for juveniles of many coastal fish species, in particular sparids and labrids. On the Western coast of Languedoc, striped bass (Dicentrarchus labrax) nurseries are localized in marinas as well as in estuaries and coastal lagoons.

Research paper thumbnail of Ecosystem-versus species-based approach of the human impact on the Mediterranean seagrass Posidonia oceanica

Biological indicators are largely used in the marine realm to (i) evaluate the quality of a water... more Biological indicators are largely used in the marine realm to (i) evaluate the quality of a water body, (ii) to weigh processes such as e.g. currents, sedimentation and climate under natural and anthropogenic forcing, and (iii) to monitor the status of species of interest, either emblematic species, indicators of ecosystem health or indicators of pollution. Sometimes, species used as biological indicators are key-species or ecosystem engineers. This is the case of the seagrass Posidonia oceanica.

Research paper thumbnail of Mapping and state of conservation of benthic marine habitats and assemblages of Port-Cros national Park (Provence, France, northwestern Mediterranean Sea). Sci. Rep. Port-Cros natl. Park, 26: 45-90

Cartographie et état de conservation des habitats et assemblages marins benthiques du Parc nation... more Cartographie et état de conservation des habitats et assemblages marins benthiques du Parc national de Port-Cros (Provence, France, Nord-Ouest de la Méditerranée). Les habitats et assemblages benthiques, ainsi que la bathymétrie, ont été cartographiés en 2010 au moyen d'un sondeur multifaisceaux interféromètre, d'un sonar latéral et d'orthophotographies, complétés par des observations en ROV (véhicule sousmarin télécommandé) et en plongée. La comparaison des données acquises en 2010 avec les cartes dressées dans les années 1960s-1970s, puis avec une carte levée en 1999, ainsi qu'avec l'ensemble des données disponibles sur Port-Cros, ne permet pas de conclure à une dégradation importante des habitats. La surface occupée par l'herbier à Posidonia oceanica n'a pas diminué et la vitalité de l'herbier est bonne à très bonne. Les grandes 'macroalgues' des Substrats durs infralittoraux à macroalgues photophiles et du Coralligène sont toujours présentes et abondantes. Le Détritique côtier se présente sous l'aspect qu'il avait peut-être en Méditerranée, avant que ses fragiles espèces calcifiées et concrétionnantes ne soient broyées par les chaluts. La gestion efficace de la pêche artisanale a permis de juxtaposer une pêche économiquement rentable avec des stocks élevés de téléostéens. En revanche, le récif-barrière de P. oceanica de la baie de Port-Cros continue à régresser ; la limite inférieure de l'herbier à P. oceanica remonte ; dans ce cas, la cause n'est pas à rechercher dans des impacts locaux, mais plus probablement dans des phénomènes climatiques. Des épisodes chauds, dont la fréquence s'accroit en -45 -liaison avec le réchauffement climatique, ont causé des mortalités massives d'espèces emblématiques, telles que les gorgones. Les forêts superficielles à Cystoseira brachycarpa var. balearica ont fortement régressé. Des 'macroalgues' introduites, envahissent la plupart des habitats ; leur impact sur la biodiversité, la structure et le fonctionnement des écosystèmes est encore mal connu. Cet impact peut s'accroître avec le temps, de telle sorte que, sur le long terme, il peut s'avérer dramatique. Au total, nos résultats traduisent d'une part le succès durable de la politique de protection du patrimoine naturel dans le Parc national de Port-Cros, mais aussi sa vulnérabilité à des impacts locaux ou venus d'ailleurs.

Research paper thumbnail of An Ecosystem-Based Approach to Assess the Status of a Mediterranean Ecosystem, the Posidonia oceanica Seagrass Meadow

Research paper thumbnail of Coastal man-made habitats: Potential nurseries for an exploited fish species, Diplodus sargus (Linnaeus, 1758)

Fisheries Research, 2013

Human pressure on seashores has induced the installation of many seawalls. Artificial coastal def... more Human pressure on seashores has induced the installation of many seawalls. Artificial coastal defence structures may be providential for the juveniles of fish species exploited by artisanal fisheries. Focusing on Diplodus sargus, the number of settling juveniles was estimated on artificial structures and on natural rocky shores. The aim is to know if these artificial areas can have a nursery function. Densities of juveniles are from 30 to 109 times greater than those in natural habitats. Artificial coastal defence structures can be regarded as artificial nurseries. However, in the studied case, they also cause the loss of the nursery function of the nearby lagoon. The artificial seawalls at the entrance to the lagoon receive almost all the larvae that would normally enter the lagoon. This study underlines the important role of these artificial habitats in the life cycle of white seabream. They may have a positive impact on maintaining other species exploited by artisanal fisheries.

Research paper thumbnail of Acoustic telemetry survey of the dusky grouper (Epinephelus marginatus) in the Marine Reserve of Cerbère-Banyuls: informations on the territoriality of this emblematic species

Comptes Rendus Biologies, 2009

The Marine Reserve of Cerbère-Banyuls represents a refuge for dusky grouper populations (Epinephe... more The Marine Reserve of Cerbère-Banyuls represents a refuge for dusky grouper populations (Epinephelus marginatus). Density survey and observation of the reproductive behavior of this species have been conducted there for the last 30 years. However, information on the behavior or habitat utilization for this species during winter time is limited. We conducted acoustic telemetry surveys from September 2005 to June 2006 in the Marine Reserve of Cerbère-Banyuls for a dusky grouper population. Six groupers were tagged and followed within the integral reserve and in the adjacent partial reserve. The results from the tracking of these individuals indicated that the largest dusky groupers are sedentary fishes with a high degree of site fidelity and a high sensitivity to variations of environmental conditions such as storms. This together with the life history characteristics of this species encourages the conservation and the protection of essential habitats of this species. Acoustic tracking coupled to the use of a fixed Kernel can be proposed to follow fish populations.

Research paper thumbnail of Evaluation of Artificial Reefs Impact on Artisanal Fisheries: Necessity of Complementary Approaches

Global Change: Mankind-Marine Environment Interactions, 2010

... Bayle-Sempere JT, Ramos-Espla AA, Charton JAG (1994) Intra-annual variability of an artificia... more ... Bayle-Sempere JT, Ramos-Espla AA, Charton JAG (1994) Intra-annual variability of an artificial reef fish assemblage in the marine reserve of Tabarca ... structure of fishes at artificial reefs off Southeastern Florida, USA Bull Mar Sci 55(2–3):796–823 Bombace G, Fabi G, Fiorentini ...