Bizerte Lagoon Research Articles

Pesticide contamination pattern of surface water in an urban–agricultural mediterranean watershed (Wadi Guenniche, Bizerte Lagoon, Northern Tunisia)

Two years of monthly sampling and hydrological monitoring were performed at the outlet of a Mediterranean watershed in northern Tunisia to determine the contents of 469 pesticide active ingredients and metabolites in water and evaluate their behavior. Wadi Guenniche is a tributary of the Bizerte coastal lagoon, with a watershed area of 86 km2, which exhibits pluvial cereal, legume, and orchid cultivation and irrigated market gardening. Twenty-nine pesticide active ingredients and 2 metabolites were detected in water. Twenty-four pesticide active ingredients were authorized for use in Tunisia. Among them, 14 had never been mentioned in previous farmer surveys. Five herbicides and their metabolites were the most frequently detected: aminomethylphosphonic acid (AMPA) (100%), glyphosate (94%), simazine (94%), 2,4-D (70%), and deisopropylatrazine (DIA) (47%). The detection frequency and concentration range suggested that the phytosanitary pressure and resulting water contamination are close to those on the northern Mediterranean shore. These results, in addition to characterizing the pollution state, emphasized the need for additional studies on the use and fate of pesticides on the southern shore of the Mediterranean Sea, particularly in Tunisia.

High levels of Polycyclic Aromatic Hydrocarbons in the Date Mussel (Lithophaga lithophaga) from Bizerte coast (northern Tunisia): Sources and human health risk implications

The date mussel Lithophaga lithophaga is protected by law in Tunisia. Still, illegal consumption of this luxury seafood has increased over time due to high demand and high prices, which have made the species regularly available in the seafood market of Bizerte, putting wild stocks at risk of decline. To raise public awareness of the risks to human health associated with the consumption of this bivalve, 16 priority polycyclic aromatic hydrocarbons (PAHs) were quantified in the soft tissue of the species, which was collected from two sites of high fishery pressure in the bay and lagoon of Bizerte. Total PAHs concentrations differ significantly between the studied sites ranging from 0.45 to 546.05 μg g−1 d.w., and were associated with port activity and the petroleum industry. The benzo(a)pyrene toxic equivalent factor and excess cancer risk showed both high values exceeding permissible limits in the polluted site. These findings provide valuable information regarding the distribution of PAHs in mussels from wild ecosystems that could be useful to prevent consumer intoxication and improve awareness against illegal harvesting of this species.

Taxonomic Composition Change after Environmental Levels Addition of Polyethylene Microplastic (PE-MPs) to Mediterranean Sediment: Case Study of Bizerte Lagoon Nematodes Communities

Taxonomic Composition Change after Environmental Levels Addition of Polyethylene Microplastic (PE-MPs) to Mediterranean Sediment: Case Study of Bizerte Lagoon Nematodes Communities

Assessment of social demand for environmental and cultural heritage preservation: evidence from a discrete choice experiment in Tunisia

Weighing cultural legacies is crucial to better understand the opportunity costs of lagoon restoration. It may be necessary for local populations whose wellbeing and culture are closely linked to heritage. This paper investigates the preferences and willingness to pay (WTP) of local fishermen for contributing to the restoration of the Bizerte lagoon (Tunisia, North Africa) and the management of the Manzel Abderrahmen harbor through the implementation of the EcoPact project. For this purpose, a discrete choice experiment (DCE) survey was conducted in the port with 50 local fishers. The results of this work represent a particular contribution to the literature as they offer a different perspective on the willingness to pay for the benefits of Cultural Bequest. Manzel Abderrahmen fishermen view “port organization” as an economic, cultural, and recreational attribute that drives their choices. The fishermen showed their willingness to accept all the taxes mentioned in the questionnaire and to increase the actual tax (9%) up to 13% over 5 years to complete the design of their port. This suggests that decision-makers should be aware of the omitted legacy values that could influence subsequent decision-making.

First detection of the invasive protozoan Haplosporidium pinnae in the critically endangered bivalve Pinna nobilis in the Southern Mediterranean Sea (Bizerte Lagoon, Tunis) and update of its current status

Pinna nobilis (Linnaeus, 1758) populations have been severely damaged in the last few decades, and since early autumn 2016, a mass mortality event (MME) has drastically impacted populations in the Mediterranean Sea. Accordingly, the aim of the present study was to improve the knowledge on the status of P. nobilis populations in the Bizerte Lagoon (Tunisia) between 2016 and 2022. Before the MME, P. nobilis was found in the lagoon at depths from 1.5 to 6 m, with a density ranging from 2 to 30 ind/100 m². After the MME, mortality reached 100% in the monitored area, except in the eastern part of the Bizerte Lagoon near the Menzel Jemil site, where some living specimens were detected. Moreover, in 2022, successful recruitment was observed in the lagoon. Additionally, our results revealed the presence of Haplosporidium pinnae and Mycobacterium sp. in some living specimens sampled in the Bizerte Lagoon after the MME. This finding constitutes the first detection of both pathogens in Tunisia and in the entire Southern Mediterranean Sea.

Tackling bioinvasions in commercially exploitable species through interdisciplinary approaches: A case study on blue crabs in Africa's Mediterranean coast (Bizerte Lagoon, Tunisia)

The Mediterranean Sea is a well-known bioinvasion hotspot, with an increasing number of non-indigenous species spreading and becoming established. Among them, the blue crabs Callinectes sapidus and Portunus pelagicus have recently called the attention due to their notable ecosystem impacts but also potential economic importance. We hereby first tackled these species through interdisciplinary approaches along the Africa's Mediterranean coast (Bizerte Lagoon, Tunisia). Molecular analyses assigned C. sapidus specimens to the Lineage 1 sensu Windsor et al. (2019), while revealed uncertainties, mismatches, and low genetic distances within the P. pelagicus species complex, suggesting that multilocus or complete mitogenomes approaches are still needed to shed light on the taxonomy and distribution of these species worldwide. Replies to questionnaires and participatory monitoring confirmed the scattered literature data available and revealed that both species have already colonized the Bizerte Lagoon and showed similar distributions, although P. segnis is more abundant and is presumably sustained by the presence of nursery grounds. Awareness campaigns strongly contributed improving the level of engagement of the local community, with low catch discards and crab taste ranked as “good” to “excellent” mostly during the second phase of the project. Crab abundances significantly affected the general perception of the fishermen in considering these species as new promising fishing targets, although educational background also played a major role among the other investigated variables. As the Bizerte Lagoon hosts a wide and native biological diversity that historically sustained local communities through small scale fishery activities and aquaculture, ecosystem-based management strategies are urged ahead of the proliferation of alien species.

Bioremediation potential of consortium Pseudomonas Stutzeri LBR and Cupriavidus Metallidurans LBJ in soil polluted by lead.

Pollution by lead (Pb) is an environmental and health threat due to the severity of its toxicity. Microbial bioremediation is an eco-friendly technique used to remediate contaminated soils. This present study was used to evaluate the effect of two bacterial strains isolated and identified from Bizerte lagoon: Cupriavidus metallidurans LBJ (C. metallidurans LBJ) and Pseudomonas stutzeri LBR (P. stutzeri LBR) on the rate of depollution of soil contaminated with Pb from Tunisia. To determine this effect, sterile and non-sterile soil was bioaugmented by P. stutzeri LBR and C. metallidurans LBJ strains individually and in a mixture for 25 days at 30°C. Results showed that the bioaugmentation of the non-sterile soil by the mixture of P. stutzeri LBR and C. metallidurans LBJ strains gave the best rate of reduction of Pb of 71.02%, compared to a rate of 58.07% and 46.47% respectively for bioaugmentation by the bacterial strains individually. In the case of the sterile soil, results showed that the reduction rate of lead was in the order of 66.96% in the case of the mixture of the two bacterial strains compared with 55.66% and 41.86% respectively for the addition of the two strains individually. These results are confirmed by analysis of the leachate from the sterile and non-sterile soil which showed an increase in the mobility and bioavailability of Pb in soil. These promising results offer another perspective for a soil bioremediation bioprocess applying bacterial bioremediation.

Nutritional Comparison of Fish Species from the Bizerte Lagoon (Mediterranean Coasts)

The present study aimed to compare the nutritional quality of three fish species (Sparus aurata, Sarpa salpa, and Mullus barbatus) collected from the Bizerte lagoon (South Mediterranean coasts). Proximate composition, fatty acids and nutritional quality indices were determined. Results showed that the nutritional quality of the three fish follows this trend: S. aurata > S. salpa > M. barbatus. S. aurata had significantly higher protein content (16.02 ± 2.01 mg/g ww), glycogen level (1.08 ± 0.16 mg/g ww), and lipid content (8.47 ± 0.96 mg/g ww) which are rich in omega-3 fatty acids (47.34%). The Total Fatty Acid (TFA) profile of S. aurata was dominated by Polyunsaturated Fatty Acids (PUFA) (70.34 ± 0.02%), followed by monounsaturated (MUFA) (20.72 ± 0.04%) and Saturated Fatty Acids (SFA) (9.03 ± 0.01%). The use of different Nutritional Quality Indices (NQI) (n-3/n-6 ratio, PUFA/SFA, EPA+DHA, Atherogenicity (AI) and Thrombogenicity (TI) indices) confirmed that S. aurata is a good source of beneficial Fatty Acids (FA) and an excellent source of nutrients. Overall, the consumption of S. aurata over S. salpa and M. barbatus is highly recommended and can be considered as a healthy food for human consumption.

An Evaluation of the Cytotoxic and Genotoxic Effects of the Marine Toxin C17-SAMT in Human TK6 and HepaRG Cell Lines.

This study investigates the genotoxicity and cytotoxicity of C17-sphinganine analog mycotoxin (C17-SAMT) using in vitro assays. C17-SAMT was previously identified as the cause of unusual toxicity in cultured mussels from the Bizerte Lagoon in northern Tunisia. While a previous in vivo genotoxicity study was inconclusive, in vitro results demonstrated that C17-SAMT induced an increase in micronucleus formation in human lymphoblastoid TK6 cells at concentrations of 0.87 µM and 1.74 µM. In addition, multiparametric cytotoxicity assays were performed in the human hepatoma HepaRG cell line, which showed that C17-SAMT induced mitochondrial dysfunction, decreased cellular ATP levels, and altered the expression of various proteins, including superoxide dismutase SOD2, heme oxygenase HO-1, and NF-κB. These results suggest that C17-SAMT is mutagenic in vitro and can induce mitochondrial dysfunction in HepaRG cells. However, the exact mode of action of this toxin requires further investigation. Overall, this study highlights the potential toxicity of C17-SAMT and the need for further research to better understand its effects.

First study of bromophenols and hexabromocyclododecanes in seafood from North Africa (case of Bizerte Lagoon, Tunisia): occurrence and human health risk.

In spite of the fact that bromophenols (BPs) and hexabromocyclododecanes (HBCDs) are widely used as flame retardants, no data was available until now on the levels of these two chemicals in North Africa biota. Seafood products might represent one of the main sources of dietary exposure to persistent organic pollutants such as non-dioxin-like polychlorinated biphenyls (ndl-PCBs), brominated flame retardants (BFRs), and polycyclic aromatic hydrocarbons (PAHs). In this study, the concentrations of the ndl-PCBs, PAH4, and BFRs were determined in seafood products from a North African lagoon (Bizerte lagoon). Almost all the compounds were detected (15 out of 18) in the analyzed marine organisms. The accumulation of the contaminants followed the order BFRs > ndl-PCB > PAH4. Mean contaminants concentrations ranged from 0.35 to 28.7ngg-1 ww for ∑ndl-PCBs; from below limit of quantification to 476ngg-1 ww for ∑BFRs and from below limit of quantification to 5.30ngg-1 ww for ∑PAH4. PCB 138, 153, and 180 were the most frequently detected ndl-PCB congeners due to their high resistance to metabolic degradation. 2,4-dibromophenol (2,4-DBP) was the predominant BFR. Chrysene (Chr) was found to be the main contributor to the total PAH4 concentration. Contaminant profiles varied significantly among seafood which may be due to the difference in lipid content, trophic level, feeding behavior, and metabolism. To assess the human health risks, the average daily dose exposure of ndl-PCBs, the dietary daily intake of PAHs and the estimated dietary intake of 3,3-,5,5-tetrabromobisphenol A (TBBPA) and HBCD from seafood were estimated. Findings indicated no adverse effects for human health from any of the analyzed contaminants, except for ndl-PCBs in eel.

Marine toxin C17-SAMT causes major structural damage to vital organs in mice following subchronic toxicity trials

C17-sphinganine analog mycotoxin (C17-SAMT) has been characterized as the contaminant responsible for the atypical toxicity reported in mussels from the Bizerte lagoon (northern Tunisia) over the past decade. C17-SAMT exhibited common symptoms of toxicity in mice, including flaccid paralysis and severe respiratory distress, followed by rapid death. To determine the potential health risks of this neurotoxin, we assessed its subchronic toxicity according to the recommendations of OCDE n° 407. The body weight and the structural changes of vital organs were recorded. Biochemical and hematological parameters were also quantified. Macroscopic observations showed that mice treated with 0.9, 9, and 90 µg/kg C17-SAMT had significantly reduced stomach weights, swollen and fragile intestines, and signs of nephritis with renal abscesses. Transaminase assays pointed out that exposure to C17-SAMT can lead to transaminitis. Above-average lactate dehydrogenase values were recorded in both the treated and satellite groups. Hematology data showed a significant reduction in red blood cell counts in high-dose-treated group. Reductions in hemoglobin and hematocrit were also recorded. Mean leukocyte counts were significantly elevated in the high-, mid-dose treated and satellite groups. At the microscopic level, we noted myocardial atrophy and hyperemia. In the lungs, we noted necrosis associated with macrophages perivascular infiltration and congestion. The kidneys showed mild inflammation and glomerular atrophy. The stomach exhibited mucosal atrophy, while a thin colon and distended small intestine were observed in high-dose-treated group. The liver was affected by vascular congestion, inflammatory infiltration, and lobular necrosis that evolved into acute hepatitis. Lesions, such as inflammatory infiltration and mild necrosis of the liver, cortical abscess with central necrosis in the kidney, and mild congestion of cardiac tissue were recorded in the satellite group.

Biometric relationships for the bivalve Ark shell Arca noae(Bivalvia; arcidae) from the Bizerte lagoon (Northern Tunisia)

Bivalves are known to exhibit wide morphological variations, which are closely linked to their ecology and reproductive activity. Therefore, the study of growth is necessary to model population dynamics, which, in turn, is crucial to support the exploitation and management of the stock. The current study aimed to analyze the shell morphological variations in the bivalve Ark shell Arca noae collected monthly from the Bizerte lagoon (northern Tunisian coasts) from October 2013 to September 2014. Allometric relationships established between linear variables (shell length and height); weight variables (total weight) and the relative growth between variables (isometry vs allometry) were analyzed. All morphometric relationships were highly significant with high correlation coefficients (R2: 0.604-0.903). Seasonal monitoring of the linear and weight relationship of the A. noae population suggested the presence of a negative allometric growth during the seasons which indicated that Ark shells are growing faster in length than in height and weight. Overall, linear and weight growth in A. noae from the Bizerte lagoon was found to be uniform and synchronous over the seasons and seems not to be influenced by the species’ reproductive cycle. This preliminary study will be useful for further research studies in biology, ecology and stock management of this non-exploited marine resource.

Fisheries activity in the Bizerta lagoon (South Mediterranean Sea) from the 18th to the 21st century

The Bizerte lagoon is characterized by its biological diversity and its wealth of species with high commercial values such as cuttlefish, seabass, seabream, mussels, prawn, and sole, and its fisheries provide employment for fishermen in the area. Indeed, artisanal fishing in the lagoon has been practiced for decades using traps, nets, and mobile gears such as straight nets and lines. The present paper focuses on the diagnosis of the fisheries’ status in this area. This allows us to reflect on the exploitation of the species caught in the Bizerte lagoon since the18th century. Large-scale hydraulic works taking place during the 20th century resulted in a reduction in the water volume inputs, inevitably affecting the fishing activity in the lagoon which we intend to analyze in the present work.

The response of meiobenthinc sediment-dwelling nematodes to pyrene: Results from open microcosms, toxicokinetics and in silico molecular interactions.

An experiment conducted with 'open microcosm' made by connected sedimentary compartments with different qualities was for 30days to evaluate the migratory behaviour of nematodes as induced by exposure to pyrene. The nematofauna was collected along with sediment from a reference site in Bizerte lagoon. Following one week acclimatization period, the populated sediments were topped with azoic sediments, with a pyrene concentration of 150μgkg-1. The concentration of pyrene from sediments was measured on a weekly basis. A stable status of nematode assemblages was reached between the upper and lower compartments in each microcosm, whatever the treatment type. An upward exploratory phase was observed during the first two weeks within the assemblages, possibly induced by the repellent chemodetection of pyrene. This observation was confirmed by the toxicokinetic properties and molecular interactions of pyrene with the germ-line development Protein 3 and sex-determining protein of Caenorhabditis elegans as nematode model.

Early diagenetic behavior of trace metals along with estimation of their diffusive fluxes: Ecological risk assessment in pore water and sediment of Bizerte Lagoon, Tunisia.

Bizerte Lagoon is a vital Mediterranean ecosystem subjected to intense anthropogenic pressure. The potential ecological risk caused by certain metals (Zn, Cu, Cr, Cd, Ni, Pb and Mn) is assessed from the data carried out in the sediment and pore water at two sites along with identifying the effects of diagenetic processes on the vertical distribution of these metals and their resulting diffusive fluxes. Using various ecological indices our results reveal a high ecological risk to benthic organisms from metals chiefly Cd, Pb and Ni accumulated in the sediment at both sites. Metals derived from organic matter degradation (Cu and Cd) and/or reduction of Mn-Fe-oxyhydroxydes (Pb, Ni, Zn, Cr) due to early diagenetic processes in sediment. The resulting concentration gradients between pore water and overlying water induce diffusive fluxes of metals to the water column. The estimation of the potential ecological risk caused by dissolved metals in pore waters by application of the Interstitial Water Criteria Toxic Units index indicates a slight ecological risk by Cu that was not identified in sediment. The ecological risk posed by dissolved metals is evidenced from -6 cm depth, which reduces the possibility of contamination of benthic species living above the water-sediment interface by diffusive fluxes of these metals.

Ecotoxicity of chrysene and phenanthrene on meiobenthic nematodes with a case study of Terschellingia longicaudata: Taxonomics, toxicokinetics, and molecular interactions modelling

Polycyclic aromatic hydrocarbons (PAHs) are toxic for humans and marine fauna alike. The current study assessed the impact of PAHs on the migratory behaviour of meiobenthic nematodes collected from the Bizerte lagoon, Tunisia. The experiment lasted for 15 days and was carried in open microcosms, which comprised a lower, contaminated and an upper, uncontaminated compartment. Three treatments were used, for each of them an untreated control was set up: sediment contaminated with chrysene (116 ng g−1 dry weight (DW), with phenanthrene (116 ng g−1 DW) and a mixture of both. The results showed a significant decrease in diversty and abundance in the lower, contaminated compartments compared to the upper zones. The results also highlighted that under an increased stress some species progressively increased in number, these were considered PAH-tolerant species such as Odontophora villoti, some others had an occasionally increased in number were considered as opportunistic species, such as Paracomesoma dubium and the species that showed a progressive decreased in number, such as Metoncholaimus pristiurus and Steineria sp., Terschellingia. longicaudata, and Oncholaimellus sp. were classified as PAH-sensitive. Moreover, an increase in the activity of biochemical biomarkers was observed following the exposure of males and gravid females of T. longicaudata to 29, 58 and 87 ng g−1 DW of chrysene and phenanthrene paralleled by a higher vulnerability of the latter demographic category. Besides, a significant decrease in fertility of females and an increase in pharyngeal sucking power were observed for both types of PAHs considered. The sex ratio was also significantly imbalanced in the favor of males, which suggest that chrysene and phenanthrene affect also the hormone system of T. longicaudata. The high affinities of these PAHs and their molecular interactions with both germ line development protein 3 (GLD-3) and sex-determining protein (SDP) may justify these results and explain the toxicokinetic attributes.

Investigation of the Genotoxic Potential of the Marine Toxin C17-SAMT Using the In Vivo Comet and Micronucleus Assays.

The contaminant responsible for the atypical toxicity reported in mussels from Bizerte Lagoon (Northern Tunisia) during the last decade has been characterized as C17-sphinganine analog mycotoxin (C17-SAMT). This neurotoxin showed common mouse toxic symptoms, including flaccid paralysis and severe dyspnea, followed by rapid death. For hazard assessment on human health, in this work we aimed to evaluate the in vivo genotoxic effects of this marine biotoxin using the classical alkaline and modified Fpg comet assays performed to detect DNA breaks and alkali-labile sites as well as oxidized bases. The micronucleus assay was used on bone marrow to detect chromosome and genome damage. C17-SAMT induces a statistically insignificant increase in DNA tail intensity at all doses in the duodenum, and in the spleen contrary to the liver, the percentage of tail DNA increased significantly at the mid dose of 300 µg/kg b.w/d. C17-SAMT did not affect the number of micronuclei in the bone marrow. Microscopic observations of the liver showed an increase in the number of mitosis and hepatocytes’ cytoplasm clarification. At this level of study, we confirm that C17-SAMT induced DNA damage in the liver but there was no evidence of effects causing DNA oxidation or chromosome and genome damage.

Evaluation of Biomonitoring Strategies to Assess Performance of a Bioremediation Bioprocess

This study was conducted to propose a suitable set of methods to evaluate the efficiency of two biotreatments. For this purpose, two sets of four 7.5 L bioreactors were followed over 90 days, containing natural sediments from the Bizerte Lagoon (Tunisia) contaminated with 35 mg·kg−1 benzo(a)pyrene (BaP) and 28 mg·kg−1 dichlorodiphenyltrichloroethane (DDT). One set was biostimulated with N/P and bioaugmented with the indigenous Pseudomonas stutzeri, Cupriavidus metallidurans and Rhodococcus equi, and the other set was only biostimulated. In the effluent, organic carbon decreased from 42 gC·L−1 to 0.2 gC·L−1 for the bioaugmented treatment compared to 15 gC·L−1 for biostimulation. Statistical analyses confirmed a significant difference in BaP concentration after bioaugmention from 35 mg·kg−1 to 21 mg·kg−1 sediment, whereas no difference was found with biostimulation. Considering DDT, biostimulation was more efficient (8.5 mg·kg−1 sediment final concentration) than bioaugmentation (15 mg·kg−1 final concentration). Native organotin and metals were also monitored using bioluminescent bioreporter strains. The bioaugmented treatment brought about a significant decrease in TBT content, to below 0.01 µM, whereas its concentration remained significant after biostimulation. The biostimulation did not alter As3+, Cu2+, Cd2+, and Hg2+ concentrations, whereas bioaugmentation induced a decrease of 1 to 2 log for each metal. At the end of the experimental period, toxicity decreased to 90% in the effluent of the bioaugmented reactors compared with a drop of only 48% for biostimulation, and a significant decrease in mutagenicity appeared for bioaugmention only. Interestingly, not all the strains used in the treatments were maintained, as P. stutzeri and R. equi increased up to densities of 8.3 × 1013 and 5.2 × 1012 DNA·g−1 sediment, respectively, while in both treatments, C. metallidurans decreased down to the detection threshold. Among the different methods used, a restricted monitoring panel of analyses appears essential to follow the change occurring over the bioremediation process: (i) organic carbon measurement reporting all biodegradation events, as well as a specific method to monitor the main compounds; (ii) dissolved N, P, O2 and pH measurements, (iii) a qPCR method to track the degraders; and (iv) measurements of the acute toxicity and the mutagenicity.

Diagenetic processes and nutrients diffusive fluxes at the sediment-water interface in the Bizerte Lagoon (North Tunisia)

Diagenetic reactions occurring in the sediments of Bizerte Lagoon along with their seasonal variation were assessed through examining the concentration profiles of nutrients and dissolved Fe and Mn in the supernatant water and pore waters, as well as the profiles of total organic carbon, carbonates, Fe and Mn contents in the particulate phase. The results indicate that these diagenetic reactions followed the classical sequence of oxidant reduction following the degradation of organic matter with a successive reduction of NO3−, MnO2, Fe (OH)3 and SO42−. In particular, a delay was observed in the winter sequence which occurred at greater depth due to higher Eh in surface layer. Generally, NO3−, NH4+ and PO43− seem to originate from sediments as reflected by their measured flux from sediments to the water column while the reverse was quoted for SO42− as reported from other Mediterranean environments. In addition, oxygenation of the water column reduces the diffusive fluxes of (NO3−, NH4+, PO43−) released into the pore water during mineralization of organic matter.

Inventory of the fauna and flora of the Northeast new ecosystem of Bizerte lagoon (Tunisia), Southeastern Mediterranean sea

Bizerte lagoon is a valuable socio-economic ecosystem which is renowned for its significant biodiversity and its strategic position in the Mediterranean and in northern Tunisia. It is characterized by an important biodiversity and a high biological productivity, which makes of it a nursery for several marine species. It is also a place of brood stock maturation for others and a feeding area for many migratory species. Its shores and maritime space host lots of human activities, such as coastal fishing, shellfish farming, maritime traffic, recreational fishing and nautical sports, besides 277 industries spanning several sectors of activity such as leather and textile as well as the refining of hydrocarbons and the steel industry. These activities cause severe pollution and result in many anthropogenic disturbances. The aim of this work is to study the sanitary state of Bizerte Lagoon using a biological and ecosystem approach that exploits bio-ecological indicators at the scale of specimen, population, community or whole ecosystem. The findings of this study have revealed the following facts: the peri-lagoon part of the Northeast zone is distinguished by an interesting biological diversity. According to statistical descriptors, the most abundant and frequent zoological groups are gastropod mollusks followed by crustaceans. In terms of diversity indexes, the values obtained showed that the Northeast zone has a poor to mediocre ecological status. This research demonstrates that Bizerte Lagoon is undergoing an anthropic pressure that has been jeopardizing the biodiversity of this ecosystem.