This study aims to investigate the responses ofthe gonads in the edible mollusk Donax trunculusto stress induced by sublethal acute cadmium (Cd) exposures and after a subsequent recovery period. We hypothesized that Cd exposure during the resting stage triggers a significant metabolic cost, redistributing energy reserves and altering protein synthesis, which may compromise the organism's fitness. The toxicological endpoints included energy-related parameters (carbohydrates, lipids, and proteins), as well as the electrophoretic composition of proteins and the RNA/DNA ratio. Samples were collected from El Battah Beach, a site distant from any source of pollution, and were reared at the laboratory. Cd was added to the rearing water at two sublethal concentrations (previously determined) corresponding to LC10and LC25; the lethal concentration required to kill 10 and 25% of the exposed individuals after 96 hours, respectively. After 96 hours, the surviving individuals were depurated in tanks containing untreated seawater for four days (recovery period). The results showed concentration-dependent effects of Cd at LC10 and LC25 concentrations on the gonadic stress responses of D. trunculus after 96 h. Both Cd treatments led to a decrease in the gonadic energy reserve levels (carbohydrates, lipids, and protein), while a qualitative analysis of proteins showed a depletion of six protein fractions (132.24, 122.44, 113.36, 68.73, 48.61 and 6.82 kDa) in Cd-exposed groups. Interestingly, a new stress-related protein fraction (41.67 kDa) was observed in the two treated series. However, clam exposures to Cd did not affect the RNA/DNA gonadic ratio. After the depuration period, clams generally recovered their initial levels of carbohydrates and lipids when compared to control values. In contrast, protein levels remained lower than those of controls. Furthermore, a new stress protein fraction (86.59 kDa) was observed, suggesting a persistent effect of Cd on protein synthesis. Overall, this experiment provides evidence supporting the benefits of depuration as a mitigation strategy to reduce Cd toxicity in bivalves before the reproduction period.
The present study describes a new species of the genus Melanella (family Eulimidae), a group of gastropods exclusively parasitic on echinoderms. Melanella holothuriborus sp. nov. is a gall-forming parasite of the intertidal sea cucumber Holothuria scabra, observed in aquaculture farms in southwestern Madagascar. Specimens were collected at Sarodrano from H. scabra reared in grow-out pens at depths of less than 10 m. The new species can be distinguished from other members of the genus Melanella by its straight shell with conspicuous growth striae, whitish apex, absence of an umbilicus, maximum shell height of 15 mm with up to 10 whorls, wide aperture, and thin, straight outer and inner lips. The gastropods induce conspicuous galls on the body surface of infested sea cucumbers. Infestation prevalence ranged from 9 to 16%, with up to 20 galls recorded per host. Galls measured 3-10 cm in diameter and contained a single large female, up to 19 males, and as many as 94 egg capsules at various developmental stages. Molecular phylogenetic analyses (16S rDNA, 18S rDNA, COI and concatenated sequences) confirmed the placement of the new species within the genus Melanella. Melanella holothuriborus sp. nov. represents the first documented case of a eulimid gastropod causing significant impacts on a commercially important aquaculture species, thereby affecting a human economic activity.
The study was conducted during the year 2021 and on a quarterly basis to measure heavy elements (cadmium, lead, copper, and nickel) within the muscle tissue of Parupeneus forsskali caught in the marine waters of Latakia Governorate. The effect of size, season, sex, and sexual maturity on the accumulation of heavy elements in muscle tissue was studied. The results showed the concentrations of heavy elements within the muscle tissue of the species studied as follows: (0.306, 1.051, 2.166, 0.475 mg.kg-1 wet weight) for cadmium, nickel, copper, and lead, respectively. Concentrations were higher in the dry season (summer and fall) than in the wet season (winter and spring), and regarding the factors of sex and sexual maturity, the results showed that there were significant differences in the concentration of most heavy elements within the muscle tissue of the species studied between males, females, and immature individuals. Regarding the size factor (total length), the results showed a positive relationship between the increase in the total length of the fish and the increase in the accumulation of heavy elements within its muscle tissue.
The fish assemblages of the Mediterranean shallow sandy shore of Israel were sampled between October 2000 and July 2002, using experimental beach seine, at three sites in close proximity to thermal effluent discharges of electric power stations and at two adjacent non-affected sites. A total of 42 species, representing 24 families, were collected. Of these, nine species (20.45%) were of Red Sea origin (Lessepsian migrants) and one (Oreochromis cf. aureus) was an escapee from aquaculture farms. The vast majority (30 species) used this habitat only as a nursery ground. The fish assemblage structure at all sites was highly stochastic, with great variations between samples. Fish assemblages were compared with regard to the number of individuals per sample and cumulative number of species and the Euclidian distance; in most parameters, no significant difference was noted between the thermal affected and non-affected sites. This finding may be attributed to the combination of the highly dynamic temporal and spatial nature of the assemblages and the rapid fading of heat leaving the relatively small effected areas.
The palaemonid shrimp genus Cuapetes Clark, 1919, belongs to the family Palaemonidae Rafinesque, 1815 and is widely distributed throughout the Indo-Pacific oceans. The genus currently comprises about 30 species, most of which are free-living and commonly associated with coral reef environments. This study documents the first record of Cuapetes andamanensis (Kemp, 1922) from the southeastern coast of India. A single ovigerous female was collected from pneumatophores of the mangrove Avicennia marina (Forssk.) Vierh. in the Vellar estuary (11 degrees 29 ' 31 '' N-79 degrees 46 ' 03 '' E). This finding significantly extends the known geographical range of C. andamanensis, which has previously been reported from the Andaman Islands, Persian Gulf, and other Indo-Pacific localities, to the Indian mainland. The report highlights the importance of continued biodiversity surveys in estuarine ecosystems to expand our understanding of regional fauna.
