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Garavelli, L., Colas, F., Verley, P., Kaplan, D. M., Yannicelli, B., & Lett, C. (2016). Influence of Biological Factors on Connectivity Patterns for Concholepas concholepas (loco) in Chile. Plos One, 11(1), e0146418.
Résumé: In marine benthic ecosystems, larval connectivity is a major process influencing the maintenance and distribution of invertebrate populations. Larval connectivity is a complex process to study as it is determined by several interacting factors. Here we use an individual-based, biophysical model, to disentangle the effects of such factors, namely larval vertical migration, larval growth, larval mortality, adults fecundity, and habitat availability, for the marine gastropod Concholepas concholepas (loco) in Chile. Lower transport success and higher dispersal distances are observed including larval vertical migration in the model. We find an overall decrease in larval transport success to settlement areas from northern to southern Chile. This spatial gradient results from the combination of current direction and intensity, seawater temperature, and available habitat. From our simulated connectivity patterns we then identify subpopulations of loco along the Chilean coast, which could serve as a basis for spatial management of this resource in the future.
Mots-Clés: Biological transport; Biophysics; Chile (country); Death rates; Fecundity; Hydrodynamics; Larvae; Marine biology
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Garrido, M., Cecchi, P., Vaquer, A., & Pasqualini, V. (2013). Effects of sample conservation on assessments of the photosynthetic efficiency of phytoplankton using PAM fluorometry. Deep-Sea Res. Part I-Oceanogr. Res. Pap., 71, 38–48.
Résumé: Pulse Amplitude Modulated (PAM) fluorometry is now a widely used method for the assessment of phytoplankton fitness, with an increasing popularity in field assessments. It is usually recommended to carry out measurements swiftly after collection, but the number of samples and analytical procedures needed to obtain valuable datasets sometimes makes immediate analysis impracticable, forcing delays between fluorescence measurements. Conservation conditions of samples before analysis may potentially affect their photosynthetic performances but no formal study documenting such impacts appears available in the literature. The aim of this study was to investigate the effects of storage conditions (temperature, duration) on photosynthetic parameters in different phytoplankton communities (characterized in situ by a BBE fluoroprobe) sampled during summer in different environmental locations in a Mediterranean lagoon (Biguglia lagoon, Corsica, France). PAM-fluorescence parameters were measured after three different conservation durations (2-4 h, 6-8 h and 10-12 h after collection) on samples stored at three different temperatures (15 degrees C, 25 degrees C and 35 degrees C). Results showed that storage at the highest temperature severely impacted photosynthetic parameters, with cumulative effects as storage duration increased. For phytoplankton samples collected in warm or tropical environments, storage at “room temperature” (25 degrees C) only appeared a valid option if measurements have to be carried out strictly within a very short delay. Inversely, cooling the samples (i.e. conservation at 15 degrees C) did not induce significant effects, independently of storage duration. Cooling appeared the best solution when sampling-to-analysis delay goes over a few hours. Long-term storage ( > 8 h) should definitively be avoided. (C) 2012 Elsevier Ltd. All rights reserved.
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GASCUEL, D., COLL, M., FOX, C., GUENETTE, S., GUITTON, J., KENNY, A., et al. (2016). Fishing impact and environmental status in European seas: a diagnosis from stock assessments and ecosystem indicators. Fish And Fisheries, 17(1), 31–55.
Résumé: Stock-based and ecosystem-based indicators are used to provide a new diagnosis of the fishing impact and environmental status of European seas. In the seven European marine ecosystems covering the Baltic and the North-east Atlantic, (i) trends in landings since 1950 were examined; (ii) syntheses of the status and trends in fish stocks were consolidated at the ecosystem level; and (iii) trends in ecosystem indicators based on landings and surveys were analysed. We show that yields began to decrease everywhere (except in the Baltic) from the mid-1970s, as a result of the over-exploitation of some major stocks. Fishermen adapted by increasing fishing effort and exploiting a wider part of the ecosystems. This was insufficient to compensate for the decrease in abundance of many stocks, and total landings have halved over the last 30 years. The highest fishing impact took place in the late 1990s, with a clear decrease in stock-based and ecosystem indicators. In particular, trophic-based indicators exhibited a continuous decreasing trend in almost all ecosystems. Over the past decade, a decrease in fishing pressure has been observed, the mean fishing mortality rate of assessed stocks being almost halved in all the considered ecosystems, but no clear recovery in the biomass and ecosystem indicators is yet apparent. In addition, the mean recruitment index was shown to decrease by around 50% in all ecosystems (except the Baltic). We conclude that building this kind of diagnosis is a key step on the path to implementing an ecosystem approach to fisheries management
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Gerigny, O., Brun, M., Fabri, M. C., Tomasino, C., Le Moigne, M., Jadaud, A., et al. (2019). Seafloor litter from the continental shelf and canyons in French Mediterranean Water: Distribution, typologies and trends. Mar. Pollut. Bull., 146, 653–666.
Résumé: Seafloor litter has been studied both on the continental shelves (by trawling during 24 years) and in canyons (by ROV) of the French Mediterranean sea Water (FMW). On the continental shelf, mean densities range from 49.63 to 289.01 items/km(2). The most abundant categories were plastic, glass/ceramics, metals and textiles. Trend analysis shows a significant increase in plastic quantities during the study period. Plastics accumulate at all depths, with heavier items being found in deeper areas, while the continental slope-break appears as a clean area. The spatial distribution of litter revealed the influence of geomorphologic factors, anthropic activities, shipping route, river inputs. All the canyons are affected by debris but coastal canyons (Ligurian Sea and Corsica) were more impacted than offshore canyons in the Gulf of Lion. The FMW appears to be highly polluted with regard to values found in other areas, but lower than those observed in the Eastern Mediterranean.
Mots-Clés: abundance; adriatic sea; areas; benthic marine litter; Canyon; Corsica; gulf; Gulf of Lion; impacts; macro; Marine litter; Mediterranean Sea; northern; plastic debris; Seafloor; strategy
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Giakoumi, S., Guilhaumon, F., Kark, S., Terlizzi, A., Claudet, J., Felline, S., et al. (2016). Space invaders; biological invasions in marine conservation planning. Divers. Distrib., 22(12), 1220–1231.
Résumé: AimBiological invasions are major contributors to global change and native biodiversity decline. However, they are overlooked in marine conservation plans. Here, we examine for the first time the extent to which marine conservation planning research has addressed (or ignored) biological invasions. Furthermore, we explore the change of spatial priorities in conservation plans when different approaches are used to incorporate the presence and impacts of invasive species. LocationGlobal analysis with a focus on the Mediterranean Sea region. MethodsWe conducted a systematic literature review consisting of three steps: (1) article selection using a search engine, (2) abstract screening and (3) review of pertinent articles, which were identified in the second step. The information extracted included the scale and geographical location of each case study as well as the approach followed regarding invasive species. We also applied the software Marxan to produce and compare conservation plans for the Mediterranean Sea that either protect, or avoid areas impacted by invasives, or ignore the issue. One case study focused on the protection of critical habitats, and the other on endemic fish species. ResultsWe found that of 119 papers on marine spatial plans in specific biogeographic regions, only three (2.5%) explicitly took into account invasive species. When comparing the different conservation plans for each case study, we found that the majority of selected sites for protection (ca. 80%) changed in the critical habitat case study, while this proportion was lower but substantial (27%) in the endemic fish species case study. Main conclusionsBiological invasions are being widely disregarded when planning for conservation in the marine environment across local to global scales. More explicit consideration of biological invasions can significantly alter spatial conservation priorities. Future conservation plans should explicitly account for biological invasions to optimize the selection of marine protected areas.
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