Combining ecosystem indicators and life cycle assessment for environmental assessment of demersal trawling in Tunisia

The approach consisted of conducting LCA and calculating ecosystem indicators to provide a complete assessment of trawling’s environmental impacts and the ecosystem characteristics associated with seafood production. The functional unit for the LCA was set to 1 t of landed seafood, and system boundaries included several operational stages related to demersal trawling. Several ecosystem indicators from EwE were calculated. Demersal trawling in the exploited ecosystem of the Gulf of Gabes (southern Tunisia) was used as a case study to illustrate the applicability of the approach. Several management plans were simulated and their influence on environmental performance was assessed. Ecospace, the spatial module of EwE, was used to simulate management scenarios: establishment of marine protected areas, extension of the biological rest period, and decrease in the number of demersal trawlers

Rearing performances and environmental assessment of sea cage farming in Tunisia using life cycle assessment (LCA) combined with PCA and HCPC

ISI Document Delivery No.: GD0MXTimes Cited: 1Cited Reference Count: 51Abdou, Khaled Lasram, Frida Ben Rais Romdhane, Mohamed Salah Le Loc'h, Francois Aubin, Joel'Institut de Recherche pour le Developpement' (JEAI GAMBAS project); LabexMerThe authors would like to acknowledge valuable financial support from the 'Institut de Recherche pour le Developpement' (JEAI GAMBAS project). This study was also partially funded by 'LabexMer'.Springer heidelbergHeidelbergThe present study aims to understand the influence of rearing practices and the contributions of production phases of fish farming to their environmental impacts and determine which practices and technical characteristics can best improve the farms' environmental performance. Another objective is to identify the influence of variability in farming practices on the environmental performances of sea cage aquaculture farms of sea bass and sea bream in Tunisia by using principal component analysis (PCA) and hierarchical clustering on principal components (HCPC) methods and then combining the classification with life cycle assessment (LCA). The approach consisted of three major steps: (i) of the 24 aquaculture farms in Tunisia, 18 were selected which follow intensive rearing practices in sea cages of European sea bass (Dicentrarchus labrax) and gilthead sea bream (Sparus aurata) and then a typology was developed to classify the studied farms into rearing practice groups using HCPC; (ii) LCA was performed on each aquaculture farm and (iii) mean impacts and contributions of production phases were calculated for each group of farms. Impact categories included acidification, eutrophication, global warming, land occupation, total cumulative energy demand and net primary production use. Results revealed high correlation between rearing practices and impacts. The feed-conversion ratio (FCR), water column depth under the cages and cage size had the greatest influence on impact intensity. Rearing practices and fish feed were the greatest contributors to the impacts studied due to the production of fish meal and oil and the low efficiency of feed use, which generated large amounts of nitrogen and phosphorus emissions. It is necessary to optimise the diet formulation and to follow better feeding strategies to lower the FCR and improve farm performance. Water column depth greatly influenced the farms' environmental performance due to the increase in waste dispersion at deeper depths, while shallow depths resulted in accumulation of organic matter and degradation of water quality. Cage size influences environmental performances of aquaculture farms. Thus, from an environmental viewpoint, decision makers should grant licences for farms in deeper water with larger cages and encourage them to improve their FCRs. This study is the first attempt to combine the HCPC method and the LCA framework to study the environmental performance of aquacultural activity. The typology developed captures the variability among farms because it considers several farm characteristics in the classification. The LCA demonstrated that technical parameters in need of improvement are related to the technical expertise of farm managers and workers and to the location of the farm

Environmental assessment of seabass (Dicentrarchus labrax) and seabream (Sparus aurata) farming from a life cycle perspective: A case study of a Tunisian aquaculture farm

WOS:000395508400024International audienceLife Cycle Assessment (LCA) was applied to assess potential environmental impacts generated by production of 1 ton of European seabass (Dicentrarchus labrax) and gilthead seabream (Sparus aurata) on a sea-cage aquaculture farmin Tunisia. The studied farm produces 2100 tons of fish per year. Impact categories included in the current study were acidification, eutrophication, global warming, land occupation, total cumulative energy demand and Net Primary Production Use (NPPuse). In addition, a refinement of "sea use"impact category was proposed to assess impacts of aquaculture on the area of sea required and seabed degradation. Calculations were performed using the software SimaPro (R) 8.0, and the database ecoinvent 3.0 was used for background data. Uncertainty analysis was performed usingMonte-Carlo simulations. Results of this study indicate that seabass rearing has lower mean impact than seabream rearing for all the impact categories considered. However, no significant differences were observed in all the impact categories except the global warming. Fish feed is the main contributor tomost of the impacts studied, which is directly related to production of fish meal and oil as feed ingredients and the large amounts of nitrogen and phosphorus released into the environment. Management decisions aiming to optimize production and use of fish feed may have a positive impact on the environmental performance of the farm. It is essential to optimize diet formulation and to followbetter feeding strategies and farming practices (e. g. stock management, feed distribution, accurate ration calculation) to lower feed-conversion ratios and consequently improve the environmental performance of aquaculture farms. LCA is a valuable tool for assessing decisions for improving environmental sustainability of aquaculture because it performs overall impact assessment and helps identify main areas for improvement

Exploring the potential effects of marine protected areas on the ecosystem structure of the Gulf of Gabes using the Ecospace model

00000 ăWOS:000386763900003International audienceThe Gulf of Gabes is considered as one of the most productive areas of the southern Mediterranean Sea and it plays an important role in Tunisian economy. It is known to be an archetypal ecosystem in which the effects of fisheries are the most pronounced. Based on the stock assessment outcomes, it is as a highly exploited ecosystem. Thereupon, it becomes necessary to establish adequate measures to facilitate the recovery of the marine resources. The most important sets of management measures regard the establishment of Marine Protected Areas (MPAs). However, these management plans should be assessed beforehand to make sure of the relevance of the measure and its impact on marine resources. Modeling may significantly enhance our understanding of the likely impacts of fisheries management plans on groups that are very difficult to study and this approach gives insights at larger spatial scales. We used Ecospace to investigate the potential impacts of several spatial management plans on the ecosystem structure of the Gulf of Gabes. The Ecospace model is based on the existing Ecopath model elaborated by Hattab (2013). The simulation were carried over a 15-year period. The outcomes of the simulations, suggest that the implementation of MPAs in the Gulf of Gabes could be simultaneously beneficial for the ecosystem and fishing activities. However, the benefits are related to the characteristics of the MPA. The spatial simulations highlight that the location is crucial to the success of the MPA. Additionally, an increase in the size of a MPA can result in an increase in the spillover effect and, consequently, in catches in the neighborhood without harming ecosystem integrity. The configuration of the implemented MPA is of capital importance, a set of many small MPAs is more beneficial than fewer and larger MPAs, especially in terms of catches

A spatio-temporal ecosystem model to simulate fishing management plans: A case of study in the Gulf of Gabes (Tunisia)

00001 ăWOS:000377228800007International audienceThe Gulf of Gabes located in southern Tunisia is one of the most productive ecosystems in the Mediterranean Sea. Despite its ecological importance, it is subject to high fishing pressure affecting the different components of the ecosystem. Given the multispecies, multigear nature of the fishery, there is a need to manage trade-offs between environmental and economic objectives. In this study, an Ecospace model was developed based on the previously constructed Ecopath model of the Gulf of Gabes and calibrated for the period 1995-2008 to investigate the response of the ecosystem to a set of alternative spatial management scenarios. These scenarios were derived from the current fishery regulation owing the important interest expressed by local fishery managers to assess new management measures. The results showed for each management scenario how bottom trawling and coastal fishing impact the different trophic groups and the complexity of interaction between these two fishing activities. Furthermore, spatially explicit simulations were performed to identify regions where the management measures are effective. Results suggested that for some trophic groups, these regions are well-defined which would be interesting to propose more accurate spatial measures. Finally, several indicators were calculated to evaluate the proposed management plans and provide managers with a straightforward set of decision rules to describe the potential trade-offs and fulfill both fisheries and conservation management objectives in the context of an ecosystem approach. The decision rules were based on observed trends to reduce uncertainty relative to the model complexity and provide consistent advice to decision makers

Environmental life cycle assessment of seafood production: A case study of trawler catches in Tunisia

International audienceThe Gulf of Gabes is one of the most productive fishery areas in the southern Mediterranean Sea. It is archetypal of an ecosystem in which the effects of fisheries are most pronounced. Demersal trawling is the main fishing activity in the Gulf of Gabes. Life Cycle Assessment (LCA) was applied to assess the environmental performance landing 1 t of seafood with wooden demersal trawlers in the Gulf of Gabes. Impact categories included in the study were abiotic depletion potential (ADP), acidification potential (AP), eutrophication potential (EP), global warming potential (GWP), ozone depletion potential (ODP), photochemical oxidant formation potential (POFP), human toxicity potential (HTP), marine eco-toxicity potential (METP), terrestrial eco-toxicity potential (TETP), land occupation potential (LOP), and total cumulative energy demand (TCED). Demersal trawlers were classified based on their impact intensity. Results showed that 70% of the vessels had relatively low impacts. Impact intensity was proportional to the amount of fuel consumed to land 1 t of seafood. Ships that fished less had the highest impacts per ton, due to lower fishing effort and catch per unit effort. This is likely to typify vessels that target highly valuable species such as shrimp. Onboard vessel activities contributed most to different environmental impacts (AP, EP, GWP and POFP), related to the high energy use of this fishery. Several impacts (ADP, ODP, METP, LOP and TCED) were associated mainly with fuel and lubricating oil production. Therefore, improvements must focus on minimizing fuel consumption. LCA is a valuable tool for assessing how to increase environmental sustainability of demersal trawling and it can help stakeholders identify the main operational issues that require improvement

Mitochondrial DNA structure of an isolated Tunisian Berber population and its relationship with Mediterranean populations.

International audienceBACKGROUND Douiret is an isolated Berber population from South-Eastern Tunisia. The strong geographic and cultural isolation characterising this population might have contributed to remarkable endogamy and consanguinity, which were practiced for several centuries. AIM The objective of this study is to evaluate the mitochondrial DNA (mtDNA) genetic structure of Douiret and to compare it to other Mediterranean populations with a special focus on major haplogroup T. SUBJECTS AND METHODS Genomic DNA was extracted from blood samples of 58 unrelated individuals collected from the different patrilineal lineages of the population. The hypervariable region 1 of the mtDNA was amplified and sequenced. For comparative analyses, additional HVS1 sequences (n = 4857) were compiled from previous studies. RESULTS The maternal background of the studied sample from Douiret was mainly of Eurasian origin (74%) followed by Sub-Saharan (17%) and North African (3%) lineages. Douiret harbours the highest frequency of haplogroup T in the Mediterranean region, assigned to the unique subclade T1a (38%). Phylogenetic analysis showed an outlier position of Douiret at the Mediterranean level. CONCLUSIONS The genetic structure of Douiret highlights the presence of founders, most likely of Near/Middle Eastern origin, who conquered this area during the Middle/Late Upper Palaeolithic and Neolithic dispersals

Association analysis of IGF2BP2, KCNJ11, and CDKAL1 polymorphisms with type 2 diabetes mellitus in a Moroccan population: a case-control study and meta-analysis.

International audienceAssociations with type 2 diabetes mellitus have been identified for variants CDKAL1 rs7756992, KCNJ11 rs5219, and IGF2BP2 rs4402960 in different populations. In a case-control study of 250 unrelated Moroccan diabetic patients and 250 healthy controls, we used TaqMan allelic discrimination assays to genotype the three SNPs and meta-analysis to investigate the association between the polymorphisms and diabetes in Arab populations. The results showed a significant diabetes association only with the variant rs4402960 of the IGF2BP2 gene under additive 2 (GG vs. TT; p = 0.009) and recessive (TT vs. GG+GT; p = 0.003) models. Meta-analysis indicated significant association between the IGF2BP2 rs4402960 and CDKAL1 rs7756992 polymorphisms and increased risk of diabetes in Arab populations. According to our results, the case-control study and meta-analysis revealed a significant association between the IGF2BP2 rs4402960 variant and type 2 diabetes in Moroccan and Arab populations

Type 2 diabetes in Mauritania: Prevalence of the undiagnosed diabetes, influence of family history and maternal effect

International audienceAim: We estimated the prevalence of undiagnosed diabetes, analyzed the influence of family history on the occurrence of T2D and evaluated its aggregation pattern in the Mauritanian population. Methods: The prevalence of unknown diabetes was obtained using data compiled from 1278 Mauritanian adults applying a questionnaire and fasting serum glucose tests. Detailed family history of diabetes and clinical characteristics were gathered from 421 T2D patients. Results: The prevalence of undiagnosed diabetes was 4.7 +/- 1.2% in the studied population (3.1% in men and 6.4% in women). 27% of T2D patients reported at least one relative with diabetes. Association between family history and diabetes was higher among first degree compared to second degree relatives (p = 0.003). We observed more probands with an affected mother than those who have a father with diabetes (p = 0.002), suggesting a preferential maternal effect which did not extend to second degree relatives. Conclusions: These results show that the prevalence of diabetes in the Mauritanian population could be higher than currently thought. Family history screening may be used in the management of this condition in Mauritania. (C) 2012 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved