Moroccan Coast Research Articles

LEVELS OF NATURAL AND ANTHROPOGENIC RADIONUCLIDES IN SEDIMENTS OF SOME MOROCCAN COASTAL AREAS AND DOSE ASSESSMENT BASED ON ERICA TOOL.

In this work, we considered the concentrations of natural and anthropogenic radionuclides (namely the 40K, 210Pb, 226Ra, 137Cs, 234Th, 228Th and 228Ra) in sediments from Moroccan coast areas by considering estuaries (Sebou and Loukkos) and marine ecosystems (M'diq Bay and three Lagoons: Moulay Bousselham, Sidi Moussa and Oualidia). Sediment samples were analyzed using Gamma spectrometry. The objective was to establish radioactivity levels in Moroccan coastal areas as well as radiological risk assessment by using the ERICA tool. The software allows the estimation of dose rates to biota (a set of reference organisms by default). The highest activity concentrations were found in sediment samples of Sidi Moussa Lagoon, possibly due to the anthropogenic activities, while the lowest levels were reported in Sebou estuary, attributed most probably to a flooding event that occurred in the same year of sampling. Also, 210Pb and 40K have the most significant concentrations, while 137Cs has the lowest concentrations with a great resemblance with similar works. The World Wide Average concentration of 226Ra was exceeded in the three lagoons and that of 40K only exceeded at Sidi Moussa Lagoon. The application of ERICA tool allowed the assessment of total dose rates that are mainly due to internal exposure with strong contribution of 226Ra mainly for phytoplankton in the case of marine ecosystems and insect larvae, mollusc-bivalve, mollusc-gastropod and zooplankton for estuary ecosystems. The total dose rates were far lesser than the admissible dose rate proposed by ERICA tool (10 μGy h-1) and, therefore, unlikely to cause harmful effects to organisms.

Stock Identification of Engraulis encrasicolus (Linnaeus, 1758) by Discriminant Function Analysis (DFA) of Morphometric Characters in The North of Atlantic and Mediterranean Moroccan Coasts

The European anchovy, Engraulis encrasicolus (Linnaeus, 1758) is a small pelagic fish found in the eastern Atlantic, the Mediterranean Sea and the Black Sea. Anchovy (E. encrasicolus) are among the important finfishes harvested in Moroccan coasts. The stock structure of European anchovy in NW Africa is not truly known (FAO, 2013). To effectively manage the anchovy fisheries, it is important to understand the anchovy stock structure. Therefore, discriminant function analysis (DFA) based on morphometric characters was conducted on a total of 204 adult anchovy specimens, seasonally collected by commercial fishing vessels from the region of Mehdia in the North Atlantic area and from the region of M’diq in the Mediterranean coast during the year 2019. Body shape variation, which is often environmentally induced, may provide a good record population structuring. Our data were subjected to univariate statistics of variance (ANOVA) by using SPSS 20 software version. The morphometric characteristics show a separation of two stocks of Engraulis encrasicolus between the two localities. These findings will have major implications for anchovy fisheries management in Morocco.

Microplastic ingestion by Atlantic horse mackerel (Trachurus trachurus) in the North and central Moroccan Atlantic coast between Larache (35°30′N) and Boujdour (26°30′N)

Horse mackerel is a semi-pelagic species found in abundance in the Moroccan coasts and occupies the first ranks in the catches landed by the coastal fleet. In this study, we investigated the ingestion of Polyamide, Acrylic and Polystyrene by Atlantic horse mackerel, in the Moroccan Atlantic coastal area located between Larache (35°30′N) and Boujdour (26°30′N). The objective is to map the spatial distribution of horse Mackerel containing microplastics (MPs) in their stomachs and identify hot spot areas. We also aim to verify the most ingested polymer by this fish characterized by significant daily vertical migrations. The results show that the three studied polymers were detected in the stomach contents of more than 73% of studied fishes. The hot spot areas are located more in the northern part where urbanization and fishing activity are important. Polyamide, the densest polymer, is the most abundant (86% of cases), followed by acrylic. These two polymers were found in association in 47% of cases. No correlation between the presence of MPs in the stomach contents and the size of the individual fishes was noted. Interestingly, the group of mature specimens ingested more MPs than the immature group.

Genetic structuring in the grooved carpet shell clam Ruditapes decussatus along the Moroccan coasts revealed by microsatellites

The grooved carpet shell clam Ruditapes decussatus is an economically important bivalve species in Morocco. Assessment of genetic diversity and genetic structure is essential for sustainable exploitation and effective management of this bivalve. Ten microsatellite loci were examined at seven localities along the Moroccan coast to determine the genetic diversity and population structure of the natural population of R. decussatus. A total of 280 clams were analyzed. The highest value of heterozygosity and mean number of alleles were found in the Mediterranean population (He: 0.685 and Na: 7.77), this can be considered in breeding and restocking programs. Five out of seven populations of R. decussatus showed signals of recent bottlenecks. Additionally, significant genetic differentiation among populations was detected (Fst =0.03125, p-val =1.021e−26). Bayesian analysis, neighbor-joining, and DAPC revealed the existence of two main groups spread on both sides of the 25th parallel. The AMOVA highlighted a genetic heterogeneity with the Southern and North group. These findings provide valuable information for efficient management and restocking based on aquaculture production for the Ruditapes decussatus inhabiting the Moroccan coasts.

Mapping total suspended matter along Moroccan coast using satellite data series

Remote-sensing techniques are a powerful technique for monitoring turbidity over the whole littoral areas. Different sensors can be used to quantify and analyze water quality parameters such as colored dissolved organic matter, total suspended sediments, chlorophyll-a, and pollutants. Therefore, the goal of this paper is to investigate the inter-annual and spatio-temporal variability’s of total suspended matter (TSM) concentration in the water surface layer. The coastal of the Atlantic Ocean, Morocco is taken an application area. The results show that high TSM (18 g m−3) is observed during winter season, and lower TSM (2 g m−3) is observed during summer season. In addition, the relationship between TSM and wind speed; and with ocean current was analyzed, and the results show that: (1) sand dredging areas usually coincide with region that have high TSM levels; (2) the wind and ocean current were both important to TSM variation; (3) the increased level of sand dredging in response to rapid economic growth has deeply influenced the TSM pattern since 2012 due to the resuspension of sediment in some areas. Visual interpretation of location led to the conclusion that the dredging activities were more located on the northern and western Morocco. Time series of MODIS images revealed a significant increase in water turbidity from 2012 onwards on the northern Morocco. Moreover, strong wind events in the northern Sahara can significantly increase the TSM in turbid coastal waters.

Checklist of rhodophyceae and the first report of Aglaothamnion tripinnatum and Gaillona gallica in the Moroccan coastline

The present study aims to update the red seaweed species in the intertidal zone of the Atlantic coast of Sidi Bouzid, a seaside resort near El Jadida City (Morocco) from 2016 to 2018. A particular interest was given to the new species recorded for the first time in the Moroccan coasts. The results obtained have shown an important red algal diversity in comparison to previous studies with 32 species of seaweeds that were found for the first time in this coastal area. A total of 156 species was recorded andrepresented by 35 families of red algae, where the largest number of these species belonged to Ceramiales order with 73 species, as well as 20 species of the order Gigartinales and 10 species for the Gelidiales and Corallinales orders. Among them, two epiphytes, Aglaothamnion tripinnatum and Gaillona gallica, are cited for the first time for the Moroccan coastline.

Reproductive biology of horse mackerel Trachurus trachurus (Linnaeus, 1758) in the North Atlantic Moroccan coast

The present study addressed the reproductive biology of the horse mackerel, Trachurus trachurus, in the northern area of the Moroccan Atlantic between December 2015 and November 2016, to provide more biological elements for stock management and good analysis of population dynamics. Monthly monitoring of the gonado-somatic index (GSI), the condition factor (K) and the stages of sexual maturity in the horse mackerel revealed that it is in reproductive activity during the period from January to June, with a peak spawning in February for females, and January for males. In addition, the length of the first sexual maturity was estimated at 21.75 cm (TL) for males and 22.75 cm (TL) for females. The evolution of the sex ratio showed a dominance of females overall size classes and during all seasons with an overall value of 0.58. The determination of fecundity allowed to assess that the total fecundity varies between 11424 and 114464 eggs with an average of 49072 ± 25045. For the relative fecundity, it varied between 159 and 770 eggs per gram of total weight, with an average of 426 ± 132, for a total length interval of 19 to 32.5 cm.

Taxonomy of the North Moroccan and Iberian species of the subgenus Amblypteraca/ (Coleoptera: Tenebrionidae: Pimeliinae: Pimelia/).

The subgenus Amblypteraca Mas-Peinado, Buckley, Ruiz García-París, 2018 of Pimelia Fabricius, 1775, is restricted to the southern Iberian Peninsula and western Maghreb (northern and western Morocco). The distribution of Amblypteraca throughout the African-European edges overlaps largely with the geographic range of the subgenus Amblyptera, which is sister to the clade grouping subgenera Amblypteraca and Ecphoroma Solier, 1836. Delimiting species boundaries in the speciose genus Pimelia is often challenging, and the taxonomic status of some groups within the aforementioned subgenera is still a matter of debate. Here, we aim to stabilize some of the available names in Amblypteraca, and to correct some previous misidentifications. For that purpose, we discuss the composition and taxonomic structure within Amblypteraca by (i) assessing the phylogenetic congruence between mitochondrial and nuclear markers, and (ii) examining external morphological traits in 568 Amblypteraca specimens under the light of the phylogenetic hypotheses proposed here. Based on our results, Amblypteraca consists of three species: P. rotundipennis Kraatz, 1865, P. fairmairii Kraatz, 1865 and P. chrysomeloides Pallas, 1781. Both molecular and morphological data revealed four lineages within P. chrysomeloides: P. chrysomeloides chrysomeloides, distributed on both sides of the Strait of Gibraltar; P. chrysomeloides fornicata Herbst, 1799 from Portugal (Troia region); P. chrysomeloides bathyglypta Antoine, 1949, restricted to a narrow strip between Larache and Arbaoua (northern atlantic Moroccan coast), and P. chrysomeloides subris Koch, 1941 from Kenitra-La Mamora forest (Morocco). We designate a neotype of Tenebrio chrysomeloides Pallas, 1781 and propose the synonymy of P. chrysomeloides (Pallas, 1781) = P. obesa Solier, 1836 syn. n. Pimelia tristis Haag-Rutenberg, 1875, previously misidentified and included in Amblypteraca, is now transferred back to Amblyptera. Further studies with ad hoc sampling designs and analytical tools would be in need to delimit the exact geographic ranges of these taxa, and to analyse the patterns of diversity within and among species and subspecies.

Bioeconomic-Epidemiological Model of Scomber colias Population in the Moroccan Coasts

In this paper, we develop and study a mathematical model for the dynamics of Scomber colias and Thunnus thynnus prey-predator with parasitic helminths. We search to analyze a bioeconomic model in which both susceptible and infected prey populations Scomber colias are exposed to the predator Thunnus thynnus, with varying degrees of exposure. However, the predator feeds preferentially on the most numerous prey types. This implies a kind of switching from the susceptible class to the infected class, and vice versa, as these two types of prey change in numerical superiority. So, the positivity, boundedness, equilibria, stability, and bioeconomic equilibrium are studied. Some numerical simulation of stability is cited. For giving a high yield and keeping the Scomber colias and Thunnus thynnus populations away from extension, we use the Maximum Principle of Pontryagin.

Hydrocarbon pollution in Atlantic coast of Mauritania (Levrier Bay Zone): Call for sustainable management

Levrier Bay is an important fishing area which is under growing anthropogenic pressures seriously threatening this treasure. Among these pressures Polycyclic Aromatic Hydrocarbon are of great environmental concern. Therefore, 16 EPA-PAHs were analyzed using GC–MS in Perna perna species and sediment. Comparison with Dakar (Senegal) and Moroccan coasts shows that PAHs levels are strikingly lower than that of heavily polluted Dakar coast (2474 μg/kg); nevertheless, comparable to Moroccan Casablanca and Tangier coasts (245 and 351 μg/kg, respectively). Ratio analysis indicates the predominance of pyrogenic sources and partial contribution of automotive traffic for the half of 4 sites. Furthermore, statistical analys shows that there are no significative differences, except for Benzo(b)Fluorentene in P. perna tissue and 4 PAHs (Fluorene; Fluorenthene; Pyrene; diBenzo(ah)Anthracene and dBahANT) in sediment for sites samples. Furthermore, bioconcentration indicates that P. perna is an excellent PAHs bioindicator. This points the necessity for immediate introduction of a sound Pollutants monitoring system.

Age, Growth and Ovarian Histology of Sardinella aurita (Valenciennes, 1847) in the South of Atlantic Moroccan Coast

Otoliths reading and length frequency distribution were used for age determination and growth estimation of Sardinella aurita (round sardinella) stock of Southern Atlantic coast of Morocco. Both otoliths' method for age determination and Bhattacharya’s method for length frequency analysis showed five age groups. The growth performance index revealed that there is significant accordance among method of length frequency distribution and otoliths reading for stock assessment studies of Sardinella aurita stock in the south of Morocco. The microscopic observation of female gonads using histology method was investigated for the first time in our study area and confirms the presence of five principal stages of ovary of sardinella aurita: immature, maturing virgin and recovering spent, mature (or pre-spawning phase), spawning, post-spawning or spent. In addition, our results of the fecundity showed that the mean relative fecundity obtained is estimated at 193 ± 98 oocytes/g which is lower compared to those obtained in other areas in the Atlantic coast.

A bioeconomic model applied to a small pelagic species along the Moroccan coast

This paper proposes a case study of five small pelagic species: Sardina pilchrdus, Sardinella, Engraulis encrasicolus, Scomber scombrus and Trachurus exploited by seiners in the maritime zones of Morocco. A comparison is made between the fishing effort calculated using the generalised Nash equilibrium problem and the actual fishing effort given by the National Institute of Fisheries Research. In this work, fishing effort represents the number of fishing trips that must be made by seiners and that allows them to maximise their gain taking into account the preservation of marine species. As a result, we find that master data of the National Institute of Fisheries Research support the outcomes shown in the end of this paper.

A bioeconomic model applied to a small pelagic species along the Moroccan coast

A bioeconomic model applied to a small pelagic species along the Moroccan coast

Bioaccumulation and health risk assessment of trace elements inMytilus galloprovincialisas sea food in the Al Hoceima coasts (Morocco)

The monthly variations in metal concentration of Cadmium (Cd), Zinc (Zn) and Chromium (Cr) were determined in tissues ofMytilus galloprovincialisand seawater obtained from the mussel farm installed along the Al Hoceima coasts, during the sampling period of 2018. The heavy metals encountered in the bivalves were higher than those observed in their environment with a decreasing order of Zn > Cr > Cd. The results also showed a decreasing trend for the metals studied during the summer sampling campaign. The maximum values were obtained during the wet periods. The monthly variations in trace metals observed in the mussel tissues were due to environmental parameters and the physiological state of the bivalves. Our results revealed that the average concentrations of pollutants found inM. galloprovincialiswere below the limits allowed by the Food and Agriculture Organization of the United Nations (FAO) which are 2.0, 1000 and 1.0 mg/kg, for Cd, Zn and Cr, respectively in molluscan shellfish for human consumption. Therefore, the trace elements present in the tissues of Al Hoceima shore mussels do not represent a risk to human health associated with their consumption, even during the period of their maximum bioaccumulation. Our work highlights the potential use ofMytilus galloprovincialisin the Biomonitoring of metallic pollutants in this region of the northern Moroccan coasts.

Offshore Wind Energy Resource in the Kingdom of Morocco: Assessment of the Seasonal Potential Variability Based on Satellite Data

This study provides a first estimate of the offshore wind power potential along the Moroccan Atlantic shelf based on remotely sensed data. An in-depth knowledge of wind potential characteristics allows assessment of the offshore wind energy project. Based on consistent daily satellite data retrieved from the Advanced Scatterometer (ASCAT) spanning the period from 2008 to 2017, the seasonal wind characteristics were statistically analyzed using the climatological Weibull distribution functions and an assessment of the Moroccan potential coastal wind energy resources was qualitatively analyzed across a range of sites likely to be suitable for possible exploitation. Also, an atlas of wind power density (WPD) at a height of 80 m was provided for the whole Moroccan coast. An examination of the bathymetrical conditions of the study area was carried out since bathymetry is among the primary factors that need to be examined with the wind potential during offshore wind project planning. The results were presented based on the average wind intensity and the prevailing direction, and also the wind power density was shown at monthly, seasonal and interannual time scale. The analysis indicated that the coastal wind regime of the southern area of Morocco has the greatest energy potential, with an average power density which can reach in some places a value around 450 W/m2 at heights of 10 m and 80 m above sea level (a.s.l) (wind turbine hub height) more particularly in the south of the country.

Induction of Natural Defenses in Tomato Seedlings by Using Alginate and Oligoalginates Derivatives Extracted from Moroccan Brown Algae.

Polysaccharides extracted from marine algae have attracted much attention due to their biotechnological applications, including therapeutics, cosmetics, and mainly in agriculture and horticulture as biostimulants, biofertilizers, and stimulators of the natural defenses of plants. This study aimed to evaluate the ability of alginate isolated from Bifurcaria bifurcata from the Moroccan coast and oligoalginates derivatives to stimulate the natural defenses of tomato seedlings. Elicitation was carried out by the internodal injection of bioelicitor solutions. The elicitor capacities were evaluated by monitoring the activity of phenylalanine ammonia-lyase (PAL) as well as polyphenols content in the leaves located above the elicitation site for 5 days. Alginate and oligoalginates treatments triggered plant defense responses, which showed their capacity to significantly induce the PAL activity and phenolic compounds accumulation in the leaves of tomato seedlings. Elicitation by alginates and oligoalginates showed an intensive induction of PAL activity, increasing from 12 h of treatment and remaining at high levels throughout the period of treatment. The amount of polyphenols in the leaves was increased rapidly and strongly from 12 h of elicitation by both saccharide solutions, representing peaks value after 24 h of application. Oligoalginates exhibited an effective elicitor capacity in polyphenols accumulation compared to alginate polymers. The alginate and oligosaccharides derivatives revealed a similar elicitor capacity in PAL activity whereas the accumulation of phenolic compounds showed a differential effect. Polysaccharides extracted from the brown seaweed Bifurcaria bifurcate and oligosaccharides derivatives induced significantly the phenylpropanoid metabolism in tomato seedlings. These results contribute to the valorization of marine biomass as a potential bioresource for plant protection against phytopathogens in the context of eco-sustainable green technology.

Lipophilic toxins occurrence in non-traditional invertebrate vectors from North Atlantic Waters (Azores, Madeira, and Morocco): Update on geographical tendencies and new challenges for monitoring routines

In the last decades, due to monitoring programs and strict legislation poisoning incidents occurrence provoked by ingestion of naturally contaminated marine organisms has decreased. However, climate change and anthropogenic interference contributed to the expansion and establishment of toxic alien species to more temperate ecosystems. In this work, the coasts of Madeira, São Miguel islands and the northwestern Moroccan coast were surveyed for four groups of lipophilic toxins (yessotoxins, azaspiracids, pectenotoxins, and spirolides), searching for new vectors and geographical tendencies. Twenty-four species benthic organisms were screened using UHPLC-MS/MS technique. We report 19 new vectors for these toxins, six of them with commercial interest (P. aspera, P. ordinaria, C. lampas, P. pollicipes, H. tuberculata and P. lividus). Regarding toxin uptake a south-north gradient was detected. This study contributes to the update of monitoring routines and legislation policies, comprising a wider range of vectors, to better serve consumers and ecosystems preservation.

Simulated Tsunami and Earthquake Impact on RC Structures: a Comparative Study

The aim of this work is to undertake a comparison of vulnerability of a reinforced concrete building located on the Moroccan coast under a tsunami and a seismic load. Tsunami and seismic loads are evaluated through FEMA P646 and the Morocco seismic building code RPS2011 respectively. Thus, a case study building is analyzed by determining its reaction and displacements due to solicitations of each hazard separately. In order to determine the capacity of the building to each hazard, two methodologies are applied: time-history analysis and pushover. Next, fragility curves are plotted according to four damage states as a function of the inundation depth for tsunamis and of spectral displacement for earthquakes. A comparison is finally held between statistical data of past tsunami events and the reported impact data. In addition, a comparison between the impacts of these two hazards allows determining the associated threat limits and drawing recommendations so that buildings can resist tsunamis and earthquakes effects.

The Western Alboran Gyre: An Analysis of Its Properties and Its Exchange with Surrounding Water

AbstractOne of the largest and most persistent features in the Alboran Sea is the Western Alboran Gyre (WAG), an anticyclonic recirculation bounded by the Atlantic Jet (AJ) to the north and the Moroccan coast to the south. Eulerian budgets from several months of a high-resolution model run are used to examine the exchange of water across the Eulerian WAG’s boundary and the processes affecting the salinity, temperature, and vorticity of the WAG. The volume transport across the sides of the WAG is found to be related to vertical isopycnal movement at the base of the gyre. Advection is found to drive a decay in the salinity minimum and anticyclonic vorticity of the Eulerian WAG. Given the large contributions of advection, a Lagrangian analysis is performed, revealing geometric aspects of the exchange that are hidden in an Eulerian view. In particular, stable and unstable manifolds identify a stirring region around the outer reaches of the gyre where water is exchanged with the WAG on a time scale of weeks. Its complement is an inner core that expands with depth and exchanges water with its surroundings on much longer time scales. The 3D evolution of one parcel, or lobe, of water as it enters the WAG is also described, identifying a general Lagrangian subduction pathway.

Hydro-meteorological characteristics and occurrence probability of extreme flood events in Moroccan High Atlas

Abstract Flood frequency analysis could be a tool to help decision-makers to size hydraulic structures. To this end, this article aims to compare two analysis methods to see how rare an extreme hydrometeorological event is, and what could be its return period. This event caused many deadly floods in southwestern Morocco. It was the result of unusual atmospheric conditions, characterized by a very low atmospheric pressure off the Moroccan coast and the passage of the jet stream further south. Assessment of frequency and return period of this extreme event is performed in a High Atlas watershed (the Ghdat Wadi) using historical floods. We took into account, on the one hand, flood peak flows and, on the other hand, flood water volumes. Statistically, both parameters are better adjusted respectively to Gamma and Log Normal distributions. However, the peak flow approach underestimates the return period of long-duration hydrographs that do not have a high peak flow, like the 2014 event. The latter is indeed better evaluated, as a rare event, by taking into account the flood water volumes. Therefore, this parameter should not be omitted in the calculation of flood probabilities for watershed management and the sizing of flood protection infrastructure.