Imaging features of retroperitoneal extra-adrenal paragangliomas in 10 dogs

Retroperitoneal paragangliomas are rare tumors of the neuroendocrine system. Only a few canine case reports are available with rare descriptions of their imaging features. The objectives of this multi-center, retrospective case series study were to describe the diagnostic imaging features of confirmed retroperitoneal paragangliomas and specify their location. Medical records and imaging studies of 10 affected dogs with cytological or histopathologic results concordant with retroperitoneal paragangliomas were evaluated. Dogs had a median age of 9 years. Four of them had clinical signs and laboratory reports compatible with excessive production of catecholamines. Six ultrasound, four CT, four radiographic, and one MRI studies were included. The paragangliomas did not have a specific location along the aorta. They were of various sizes (median 33 mm, range: 9-85 mm of length). Masses had heterogeneous parenchyma in six of 10 dogs, regardless of the imaging modality. Strong contrast enhancement was found in all CT studies. Encircling of at least one vessel was detected in six of 10 masses, clear invasion of a vessel was identified in one of 10 masses. In five of 10 cases, the masses were initially misconstrued as lymph nodes by the on-site radiologist. Retroperitoneal paragangliomas appear along the abdominal aorta, often presenting heterogeneous parenchyma, possibly affecting the local vasculature, and displaying strong contrast enhancement on CT. Clinical signs can be secondary to mass effects or excessive catecholamine production. Underdiagnosis and misdiagnosis of this tumor are suspected as they can be silent, of small size, or confused with other structures

The self-sustaining decomposition of ammonium nitrate fertiliser: Case study, Escombreras valley, Spain

Fertilizers containing ammonium nitrate have caused several accidents over time, including toxic clouds, fires and explosions. Therefore, in this work we have studied the accident produced in Escombreras (Spain) related to the decomposition of fertilizer NPK 15-15-15 composed basically of monoammonium phosphate, ammonium nitrate and potassium chloride. The fertilizer was stored in a silo and its decomposition produced a toxic cloud formed by nitrogen oxides. Calculations have been made to determine the amount of heat released in the accident and the temperature gradient in the stored pile. The causes of the accident are not clear but could be related to the presence of decomposing organic matter. The fault tree has revealed several weak points in the storage conditions. The dispersion of the gases produced has been simulated to evaluate the distance to which dangerous concentrations of gases would reach. The consequences of the accident are met with almost 4000 people affected although most of them only with minor irritations and episodes of confinement of the nearby population. To conclude, a series of lessons have been extracted that can help avoid similar accidents in the future

Patterns of predation on native and invasive alien fish in Mediterranean protected and unprotected areas

Worldwide, the loss of predatory fish due to overexploitation has altered the structure of native communities and caused ecosystem shifts. Ecosystems deprived of high-level predators may be more vulnerable to invasive alien species as the latter are subject to reduced predation control. Marine protected areas (MPAs), and particularly no-take reserves where fishing is banned, can be effective tools for the restoration of predatory relationships within their boundaries. We explored whether the restoration of high-level predatory fish populations within Mediterranean MPAs can exert top-down control on alien fish. Fish tethering experiments, including native (Sardina pilchardus, Boops boops) and alien (Siganus rivulatus) dead specimens, were conducted to quantify predation within the no-take zones of three MPAs and in unprotected areas, and to assess potential differences in predation rates and prey type preferences. A subsample of experimental units was filmed to document predation events and related fish behaviour. More high-level predators interacted with the tethered fish inside the MPAs than in unprotected areas. Yet we did not find significant differences in the consumption of alien or native fishes between MPAs and unprotected areas. The native S. pilchardus was consumed more in comparison to the other tethered fishes, regardless of protection status and location. Interestingly, the alien S. rivulatus was consumed by native predators in the western Mediterranean locations where this alien fish is not established. Despite its limitations, our study provides evidence on the ability of some native predators to feed on and potentially control certain alien species without requiring ‘adaptive’ time-lag periods

Thermal threshold and sensitivity of the only symbiotic Mediterranean gorgonian Eunicella singularis by morphometric and genotypic analyses

International audienceThe only symbiotic Mediterranean gorgonian, Eunicella singularis, has faced several mortality events connected to abnormal high temperatures. Since thermotolerance data remain scarce, heat-induced necrosis was monitored in aquarium by morphometric analysis. Gorgonian tips were sampled at two sites: Medes (Spain) and Riou (France) Islands, and at two depths: 15 m and-35 m. Although coming from contrasting thermal regimes, seawater above 28 degrees C led to rapid and complete tissue necrosis for all four populations. However, at 27 degrees C, the time length leading to 50% tissue necrosis allowed us to classify samples within three classes of thermal sensitivity. Irrespectively of the depth, Medes specimens were either very sensitive or resistant, while Riou fragments presented a medium sensitivity. Microsatellite analysis revealed that host and symbiont were genetically differentiated between sites, but not between depths. Finally, these genetic differentiations were not directly correlated to a specific thermal sensitivity whose molecular bases remain to be discovered

Optimizing canopy‐forming algae conservation and restoration with a new herbivorous fish deterrent device

International audienceThe role of herbivorous fish in threatening marine forests of temperate seas has been generally overlooked. Only recently, the scientific community has highlighted that high fish herbivory can lead to regime shifts from canopy-forming algae to less complex turf communities. Here, we present an innovative herbivorous Fish Deterrent device (DeFish), which can be used for conservation and restoration of marine forests. Compared to most traditional fish exclusion systems, such as cages, the DeFish system does not need regular cleaning and maintenance making it more cost-efficient. Resistance of DeFish was tested by installing prototypes at different depths in the French Riviera and in Montenegro: more than 60\% of the devices endured several years without maintenance, even if most of them were slightly damaged in the exposed site in Montenegro. The efficacy of DeFish in limiting fish herbivory was tested by an exclusion experiment on Cystoseira amentacea in the French Riviera. In a few months, the number of fish bite marks on the seaweed was decreased, causing a consequent increase in algal length. The device here presented has been conceived for Mediterranean canopy-forming algae, but the same concept can be applied to other species vulnerable to fish herbivory, such as kelps or seagrasses. In particular, the DeFish design could be improved using more robust and biodegradable materials. Innovative engineering systems, such as DeFish, are expected to become useful tools in the conservation and restoration of marine forests, to complement other practices including active reforestation, herbivore regulation and regular monitoring of their status. This article is protected by copyright. All rights reserved

Artificial reef effectiveness changes among types as revealed by underwater hyperspectral imagery

Artificial reefs (ARs) are designed to mimic natural habitats and promote marine life. Their effectiveness is however debatable and can depend on factors such as structural complexity and construction material. Old artificial reefs (OARs) were made of concrete mold of simple geometric shapes, limiting their ability to mimic the complexity of natural reefs. Recent advancements in three-dimentional (3D)-printing technology have enabled the creation of 3D-printed artificial reefs (3DRs) with biocompatible material and complex structures that can better simulate the natural habitats. We employed underwater hyperspectral technology to estimate the performance of these reefs and compare the benthic photosynthetic signal of natural reefs (NATs) with those of ARs (OARs and 3DRs) in coastal area of the north-western Mediterranean (France and Monaco Principality). We expected differences in reflectance signals between OARs and NATs, and signals closer to NATs in 3DRs than OARs. Underwater hyperspectral technology was able to detect higher chlorophyll-a derived signals on NATs than OARs. Moreover, the magnitude of differences between 3DRs and NATs was smaller than that between OARs and NATs. Although ARs were not capable of mimicking natural reefs, the use of 3D-printed ARs might ameliorate their effectiveness for coastal reconciliation

Analyse par imagerie hyperspectrale sous-marine : Révéler la variabilité de l'efficacité des récifs artificiels

International audiencePoster illustrant l'usage de l'imagerie hyperspectral sous marine pour évaluer l'efficacité des récifs artificiels à imiter le signal photosynthétique des assemblages des habitats naturels adjacents. Etude de cas effectué en Principauté de Monaco en 2020

Distribution patterns of marine cave fishes and the potential role of the cardinal fish

Fish assemblages associated with 16 marine caves were investigated along the coasts of Spain, France and Italy. Sampling was done in caves that encompassed blind caves (one entrance) and caves with several openings, remarkably variable in morphology, overall extension, presence/absence of ceiling, and characteristics of the bottom. On the whole, 33 fish species were recorded. The distribution patterns of fish assemblages (both in terms of density and biomass) showed a significant variability at the regional (hundreds of kms) and local scale (kms/hundreds of meters), which confirms the great heterogeneity of the cave-associated communities. In terms of occurrence, only the cardinal fish Apogon imberbis and the gobid Corcyrogobius liechtensteini were found in all 16 caves, followed by Scorpaena notata and Serranus cabrilla (n = 15) and Diplodus vulgaris and Didogobius splechtnai (n = 11). A significant number of species were occasionally found, like Sarpa salpa and Diplodus annularis. They usually occur outside caves and could be considered as “sporadic cave visitors”. The high densities of A. imberbis and its frequency of occurrence shows that this species is by far the most represented fish within caves in the western Mediterranean. In spite of the conspicuous variation from cave to cave (from 10 to 70% of the whole fish biomass), a general pattern emerges showing that A. imberbis accounts for a significant proportion of the fish biomass. Average density and biomass of A. imberbis are significantly variable at regional scale (hundreds of kms), but not at local scale (kms/hundred meters). A similar pattern could be explained by multiple processes acting concurrently. Although further studies are needed (e.g. to prove nychthemeral movements inside–outside caves for feeding), this study shows that, based on its density and biomass, A. imberbis has the potential to fulfill a crucial trophic role within Mediterranean marine caves as a vector of organic matter

Threats to large brown algal forests in temperate seas: the overlooked role of native herbivorous fish

International audienceCanopy-forming algae are declining globally due to multiple disturbances. This decline has recently been on the increase due to the spread of some tropical herbivorous fishes. This new phenomenon has drawn attention to the effects of fish herbivory in temperate areas, which have been assumed to be negligible compared to that of invertebrates, such as sea urchins. In this study, the impact of a Mediterranean native herbivorous fish (Sarpa salpa, salema) was assessed on the canopy-forming seaweed Cystoseira amentacea var. stricta. Cystoseira amentacea forms belts in the infralittoral fringe of wave-exposed shores, which has so far been considered a refuge from fish herbivory. To test the effects of salema feeding on natural C. amentacea belts, an innovative herbivore deterrent device was conceived. Salema had a significant effect on C. amentacea by decreasing algal size, biomass and fertility, by up to 97%. The results suggest that the contribution of salema feeding to the loss of Cystoseira forests in the Mediterranean may have been overlooked. In addition, the analysis of temporal and spatial patterns of salema landings in the Mediterranean Sea suggests that salema abundance may have increased recently. Thus, along with invertebrate herbivory and anthropogenic stressors, fish herbivory may also represent a potential threat to algal forests in temperate areas