The Green Wave: Reviewing the Environmental Impacts of the Invasive European Green Crab (Carcinus maenas) and Potential Management Approaches

The European green crab (Carcinus maenas), native to northwestern Europe and Africa, is among the top 100 most damaging invasive species globally. In some regions, including the Atlantic coast of North America, C. maenas has caused long-term degradation of eelgrass habitats and bivalve, crab, and finfish populations, while areas are near the beginning of the invasion cycle. Due to high persistence and reproductive potential of C. maenas populations, most local and regional mitigation efforts no longer strive for extirpation and instead focus on population control. Long-term monitoring and rapid response protocols can facilitate early detection of introductions that is critical to inform management decisions related to green crab control or extirpation. Once C. maenas are detected, local area managers will need to decide on management actions, including whether and what green crab control measures will be implemented, if local invasion might be prevented or extirpated, and if population reduction to achieve functional eradication is achievable. Due to the immense operational demands likely required to extirpate C. maenas populations, combined with limited resources for monitoring and removal, it is unlikely that any single government, conservation and/or academic organization would be positioned to adequately control or extirpate populations in local areas, highlighting the importance of collaborative efforts. Community-based monitoring, and emerging methods such as environmental DNA (eDNA), may help expand the spatial and temporal extent of monitoring, facilitating early detection and removal of C. maenas. While several C. maenas removal programs have succeeded in reducing their populations, to our knowledge, no program has yet successfully extirpated the invader; and the cost of any such program would likely be immense and unsustainable over the long-term. An alternative approach is functional eradication, whereby C. maenas populations are reduced below threshold levels such that ecosystem impacts are minimized. Less funding and effort would likely be required to achieve and maintain functional eradication compared to extirpation. In either case, continual control efforts will be required as C. maenas populations can quickly increase from low densities and larval re-introductions.

IMPACT OF THE PORT STRUCTURE IN THE SPATIO-TEMPORAL EVOLUTION OF THE SEDIMENTARY AND BATHYMETRIC CHARACTERISTICS OF A MOROCCAN ATLANTIC BAY, STUDY CASE BAY OF SAFI CITY

This study focuses on morpho-sedimentary changes in the bay of Safi (Atlantic coast of Morocco), due to a progressive extension of the port. For this purpose, several bathymetric and sedimentary surveys carried out by the Hydrographic and Oceanographic Service of the Navy (SHOM) in 1892, 1906 and 1940 respectively, coupled with a bathymetric and sedimentary measurement mission in 2009, were analyzed to understand the impact of the port developments on the bottom of Safi Bay. This analysis consists of making maps of the evolution of (i) sedimentary facies (of different dates 1892, 1906, 1940 and 2009) and (ii) the shallow seabed of the three periods 1892–1906, 1906–1940 and 1940–2009. The sedimentary facies maps show that the facies appear unstable and evolve intermittently in response to environmental changes in the bay (port construction and expansion). In addition, the overlay of the bathymetric maps indicates that the bay has undergone changes (lowering, stability, and raising) controlled by hydrodynamic conditions before, during, and even after harbor construction. Analysis of the data showed that the expansion of the port often reshaped the morphology of the bay's seabed. The consequences of these evolutions are the appearance of the fattening or the erosion of the bank and the filling of small depressions of sediments. This evolution is reflected in the modification of the funds near the port and the beach of Safi.

AUTOMATIC FISH DETECTION FROM DIFFERENT MARINE ENVIRONMENTS VIDEO USING DEEP LEARNING

The marine environment provides many ecosystems that support habitats biodiversity. Benthic habitats and fish species associations are investigated using underwater gears to secure and manage these marine ecosystems in a sustainable manner. The current study evaluates the possibility of using deep learning methods in particular the You Only Look Once version 3 algorithm to detect fish in different environments such as; different shading, low light, and high noise within images and by each frame within an underwater video, recorded in the Atlantic Coast of Morocco. The training dataset was collected from Open Images Dataset V6, a total of 1295 Fish images were captured and split into a training set and a test set. An optimization approach was applied to the YOLOv3 algorithm which is data augmentation transformation to provide more learning samples. The mean average precision (mAP) metric was applied to measure the YOLOv3 model’s performance. Results of this study revealed with a mAP of 91,3% the proposed method is proved to have the capability of detecting fish species in different natural marine environments also it has the potential to be applied to detect other underwater species and substratum.

DISTRIBUTION OF DINOCYSTS IN THE SURFACE SEDIMENTS OF SIDI MOUSSA LAGOON : (ATLANTIC COAST-MOROCCO)

The Sidi Moussa lagoon, (32°52′0″ N / 8° 51′05″ W) is located on the Moroccan Atlantic coast between the cities of El Jadida and Safi about 15 km South of the Jorf Lasfar industrial complex, The climate of the lagoon is classified as hot temperate. It is characterised by an oceanic influence. This study of dinoflagellate cyst mapping is the first of its kind from the Sidi Moussa lagoon. the objectives of the present survey were (i) to evaluate to the spatial variation of dinoflagellate cyst assemblages in the sediment along the Sidi Moussa lagoon (ii) to assess the densities of its cysts (iii) to compare the cyst assemblages in this study with that of other sites. The data were collected in a scientific campaign by zodiac carried out from in April 2018 by core following a sampling network of 21 stations distributed randomly in the study area. The surface layer of the sediment cores (3 cm) was sliced and kept at 4° C until analysis. The highest total cyst abundance was 194 cysts. g−1 dry sediment. The Pearson statistical test revealed a positive and significant correlation between cyst abundance and water content, organic matter and of fine sediment. Our study showed the presence of morphotypes of potentially toxic species. The cysts of these species present in the sediment of the Sidi Moussa lagoon could germinate, when environmental conditions become favorable, and in turn could inoculate the water column with the subsequent bloom formation. This study confirms the usefulness of cyst analysis in the assessment of harmful bloom risk in this area important for oyster’s culture.

Diversity of marine benthic algae from Cantabria (Eastern Cantabrian, Spain): a historical overview of research and publications

The macroalgal flora of Cantabria (north of Spain) has attracted the interest of many researchers on past occasions. Currently published information only reflects occasional collections from sporadic field visits to this region of the Spanish Atlantic coast. To overcome this, a historical overview of research and publications, encompassing collections and presence data recording, has been undertaken. This work lists the resultant taxonomic records and provides information about macroalgal flora of Cantabria. A total of 425 species (25 Cyanobacteria, 55 Chlorophyta, 81 Ochrophyta, and 264 Rhodophyta) were identified. The number of specific, infraspecific taxa, and stages is 437: 25 Cyanobacteria, 57 Chlorophyta, 89 Ochrophyta, and 266 Rhodophyta. The floristic character of flora from the Cantabrian coast is compared over time and with nearby regions applying Cheney’s ratio [(Rhodophyta+Chlorophyta)/ Ochrophyta, or (R+C)/O]. The present paper aims to provide an overview of the research that has been conducted in the Cantabrian coast, not only found in international publications but also in local publications as well as unpublished theses.

STUDY OF MORPHODYNAMIC AND SEDIMENTOLOGICAL CHANGES IN THE OUALIDIA LAGOON (MOROCCO) USING BATHYMETRIC DATA: FIRST INVESTIGATIONS AFTER THE SEDIMENT TRAP DREDGING

Coastal lagoons are highly dynamic and physically complicated systems. They are environmentally productive and socio-economically valuable. Contemporary global development and management pressures require a better understanding of their dynamics and sustainability. The present study focuses on the problem of water confinement in the Oualidia lagoon (Atlantic coast of Morocco). This lagoon is characterized by an asymmetric tidal propagation, with a shorter duration of the flood (rising tide) than the ebb (falling tide). In the long term, this contributes to the reduction of depths and the confinement of water upstream. After extensive studies, a sediment trap was created in 2011 to trap the finest sediment in the upstream part of the lagoon. This study aims to analyze the morphodynamical and sedimentological changes in the lagoon of Oualidia, after the sediment trap dredging. For this purpose, bathymetric surveys covering 6 years between 2006 and 2012 were analyzed, providing sufficient data to identify the morphological changes that the lagoon has undergone during this period. The data analysis was followed by a study of the lagoon bed dynamics using profile lines extracted from the bathymetric data in a GIS environment. As a result, the findings partly show that over 6 years, an average height of +0.65 m was gained by the lagoon, while the average change in the eroded areas was estimated to be −0.42 m. In addition, the eroded area in the lagoon was estimated to be about 1,513,800 m2 with an erosion volume of 633,383 m3, while the accumulated area found was about 2,699,396 m2 with an accumulation volume of 1,765,866 m3. These changes can be related to the large input of marine sediment, mainly caused by tidal currents and waves, but also to the creation of a sediment trap in the upstream area of the lagoon.

Queen triggerfish Balistes vetula: Validation of otolith-based age, growth, and longevity estimates via application of bomb radiocarbon

Ensuring the accuracy of age estimation in fisheries science through validation is an essential step in managing species for long-term sustainable harvest. The current study used Δ14 C in direct validation of age estimation for queen triggerfish Balistes vetula and conclusively documented that triggerfish sagittal otoliths provide more accurate and precise age estimates relative to dorsal spines. Caribbean fish samples (n = 2045) ranged in size from 67–473 mm fork length (FL); 23 fish from waters of the southeastern U.S. (SEUS) Atlantic coast ranged in size from 355–525 mm FL. Otolith-based age estimates from Caribbean fish range from 0–23 y, dorsal spine-based age estimates ranged from 1–14 y. Otolith-based age estimates for fish from the SEUS ranged from 8–40 y. Growth function estimates from otoliths in the current study (L∞ = 444, K = 0.13, t0 = -1.12) differed from spined-derived estimates in the literature. Our work indicates that previously reported maximum ages for Balistes species based on spine-derived age estimates may underestimate longevity of these species since queen triggerfish otolith-based ageing extended maximum known age for the species by nearly three-fold (14 y from spines versus 40 y from otoliths). Future research seeking to document age and growth population parameters of Balistes species should strongly consider incorporating otolith-based ageing in the research design.

Effects of Groundwater Inputs to the Hydraulic Circulation, Water Residence Time, and Salinity in a Moroccan Atlantic Lagoon

The finite element model SHYFEM was used to study the hydrodynamics and variability of water level, salinity, temperature, and water residence time (WRT) in the Oualidia lagoon located on the Moroccan Atlantic coast. The lagoon hosts a RAMSAR convention-protected area and also offers a set of valuable ecosystem services providing the source of income for the local population. To assess the effects of submarine groundwater discharge (SGD) inputs in the study area, four simulations were set up using different SGD inputs estimates in addition to tidal forcing, bathymetry, meteorological data including solar radiation, rain, and wind, in addition to boundary conditions in the Atlantic such as salinity, water level, and water temperature. The model was calibrated and validated using hydrodynamic measurements of previous studies in 2012 and 2013. The final results from the model are in good agreement with measured data. The simulation with SGD input ~0.05 m3 s−1 produced salinity values closest to the observed ones. Calculated spatial distribution of WRT, temperature, and salinity reduced to coordinates in two PCA axes is consistent with lagoon zones developed earlier using the benthic macroinvertebrate distribution. The calculated spatial distribution of WRT allowed us to evaluate the placement of oyster aquaculture farms and small-scale fisheries in relation to water quality issues existing in the lagoon.

Extinction in transition: coca, coal, and the production of enmity in Colombia's post-peace accords environment

At the Paris Climate Summit in 2015, then Colombian president Juan Manuel Santos proposed constructing a multi-national biodiversity corridor that would extend from the Andes to the Brazilian Atlantic coast. Santos highlighted increased militarization of the territory as one advantage of the corridor. In this model, ecological conservation becomes a matter of national/natural security, in the form of counterinsurgency to counter illegal economies. Climate change and ecological disaster mean the forest needs the military power of the State to save it from destruction. We argue that such conservation entails a form of necropolitics lying in wait; because to conserve one part is to condemn the other – framed as the enemy – to certain destruction, as land is simultaneously designated for large-scale development projects. Conservation, in effect, becomes tied to a form of extinction. Our article examines two increasingly militarized frontiers that work through conservation in Colombia. The first is where the Andes meets the Amazon rainforest, an area that has seen an increase in deforestation following the 2016 Peace Agreement with the FARC. Deforestation is often attributed to the cultivation of coca (used to produce cocaine), and the solution posited by the government is to eradicate the plant. We argue that eradication of illicit crops is a form of enforced extinction that militarizes the forest, targeting both human and non-human inhabitants. The second frontier concerns coal mining on the Caribbean coast, where mass environmental devastation induced by the industry has led to a forced reorganization of life in the region. The military guards the sites of extraction and those who oppose coal mining become targets for elimination. We bring these two cases – coal and coca – into dialogue, to trace the extinction-driven expansion of extractive economies, a process intertwined with armed conflict, narcotrafficking, and now with transitional politics.