Search results for "crustacean"

Trawl mesh selectivity and body engagement pattern in the red shrimpAristaeomorpha foliacea(Risso, 1827) (Crustacea: Decapoda)

1998

The paper presents selectivity data and utilizes an elliptic surface index (maximum height and width of the folded body), in order to explain the selectivity differences between sexes and to investigate the body engagement pattern of the red shrimp Aristaeomorpha foliacea. The results show that males are retained more, with significant differences, and demonstrates a previously unknown morphological difference between sexes (folded males are significantly higher than females of the same carapace length, while the latter are larger, but not significantly, than males of similar size). Nevertheless, in practice the overall escapement rate should not change dramatically with sex, since the resu…

Assessment of the efficacy of Artemia sp (Crustacea) cysts chorion as barrier to chlorpyrifos (organophosphorus pesticide) exposure. Effect on hatchi…

2005

In order to reveal the efficacy of the Artemia cysts chorion as barrier to the organophosphorus pesticide chlorpyrifos, whole and decapsulated cysts have been exposed to 10 mg L(-1) chlorpyrifos in sea water during hydration and hatching phase, separately. The concentration of chlorpyrifos in capsulated and decapsulated cysts after exposure has been determined in order to elucidate the efficacy of chorion as protection to the embryo. The results obtained demonstrate the ability of the cysts chorion to obstruct the pass of chlorpyrifos molecules through this protection structure. Thus, the concentration of chlorpyrifos in exposed decapsulated cysts is higher than in exposed whole cysts. More…

UV Radiation and Freshwater Zooplankton: Damage, Protection and Recovery

2011

While many laboratory and field studies show that zooplankton are negatively affected when exposed to high intensities of ultraviolet radiation (UVR), most studies also indicate that zooplankton are well adapted to cope with large variations in their UVR exposure in the pelagic zone of lakes. The response mechanisms of zooplankton are diverse and efficient and may explain the success and richness of freshwater zooplankton in optically variable waters. While no single behavioural or physiological protection mechanism seems to be superior, and while several unexplained and contradictory patterns exist in zooplankton UVR ecology, recent increases in our understanding are consistent with UVR pl…

�ber Die Geschlechtsbeeinflussende Wirkung Von Farballelen Bei Gammarus Pulex SSP. Subterraneus (Schneider)

1957

Seasonal studies of the biology ofAchtheres percarumin perch,Perca fluviatilis, from four Finnish lakes over a 3-year period

1993

Achtheres percarum infection on the gills of perch Perca fluviatilis was studied from four lakes in central Finland in monthly or bimonthly samples of fish during a 3-year period. The highest prevalence and intensity of infection (30%, 0.7 copepods/fish) were found in the oligotrophic, unpolluted Lake Peurunka and the lowest (6%, 0.1 copepods/fish) in the eutrophic and polluted Lake Vatia. According to hierarchical loglinear models the prevalence of A. percarum infection was related to the lake, but not to the year. However, when logit models were constructed such that two ‘seasons’ (‘cold’ and ‘warm’ periods) were included, it was apparent that the year also influenced the prevalence of A.…

Histological and electron microscopical observations on the effects of lead on gills and midgut gland ofProcambarus clarkii

1991

Adult intermolt specimen of Procambarus clarkii (Crustacea, Decapoda) have been treated for 96 hours in aquaria with 100mg/l of lead. The gills and midgut gland were processed and studied in the electron microscope. The gill filament shows important changes in the ultrastructure of the epithelial cells and the cuticle. The hepatopancreatic cells studied (i.e. the vacuolated and dark cells) do not show noticeable structural changes but accumulate lead (electrondense precipitates) mainly in lysosomes.

Determination of lead in treated crayfish Procambarus clarkii: accumulation in different tissues.

1988

The continual loading of trace metals into our environment represents a water pollution problem due to their toxic effects on aquatic biota. In addition, metal ions can be incorporated into food chains and concentrated by aquatic organisms to a level that affects their physiological state. There are several investigations on the toxic effects and bioaccumulation of lead in fishes, molluscs, and crustaceans. Lake Albufera (Valencia, Spain) and the surrounding rice-field waters are subjected to large loads of sewage and toxic industrial residues (including heavy metals) from many urban wastewaters in the area. In 1978, the American red crayfish Procambarus clarkii (Girard) appeared in Lake Al…

REDUCTION IN THE LEVEL OF INFECTION OF THE BIVALVE ANODONTA PISCINALIS BY THE COPEPOD PARAERGASILUS RYLOVI USING HIGH TEMPERATURE AND LOW OXYGEN

2003

The aim of this study was to develop a method to kill or expel the gill-dwelling crustacean parasite Paraergasilus rylovi from a common freshwater clam, Anodonta piscinalis. Naturally infected clams were exposed to different water-quality treatments and monitoring in the laboratory. In a high-temperature treatment (26 C vs. control 18 C), the mean abundance of the parasite decreased to near zero in 7 days. Because only 2 clams of 72 died in this treatment during the 14-day experiment, the survival of the host was not seriously at risk at the high temperature. 'Low oxygen, no water change' (18 C) was the second most effective treatment, followed by a 'low-oxygen, water-flow' (18 C) treatment…

On the non-malacostracan crustaceans (Crustacea: Branchiopoda, Copepoda, Ostracoda) from the inland waters of Fthiotida (Greece)

2019

In the frame of the activities of the LIFE11 NAT/GR/1014 ForOpenForests, some water bodies occurring in the "Ethnikos Drymos Oitis" (GR2440004) and "Oros Kallidromo" (GR2440006) (Sterea Ellada) were investigated with the aim of providing a first census of the composition and diversity of their crustacean fauna. Overall, the sampling of 15 water bodies (7 of them listed as "Mediterranean temporary ponds" sensu EU "Habitats Directive") led to the finding of 13 branchiopod, 11 copepod, and 7 ostracod taxa, including 4 species new for mainland Greece, i.e. the copepods Arctodiaptomus alpinus (Imhoff, 1885) and Diaptomus cf. serbicus, and the branchiopods Leptestheria dahalacensis (Rüppel, 1837)…

An updated checklist and biogeography of the Sardinian large branchiopods, with a focus on Spinicaudata (Crustacea, Branchiopoda)

2021

Author(s): Marrone, Federico; Alfonso, Giuseppe; Cottarelli, Vezio; Botta, Marco Massimo; Koepp, Christian; Stoch, Fabio | Abstract: The large branchiopod fauna of Sardinia is reviewed based both on literature and newly collected data. Based on the available evidence, 13 taxa are present on the island (8 Anostraca, 2 Notostraca, and 3 Spinicaudata). Among them, the finding of the spinicaudatan Leptestheria dahalacensis is new for Sardinia, while the spinicaudatans Cyzicus bucheti and Eulimnadia sp. were overlooked in the most recent synopses on the fauna of the island due to misidentifications. Conversely, Cyzicus tetracerus and Limnadia lenticularis, previously erroneously reported based o…