Search results for "Crayfish"
showing 7 items of 67 documents
Comparative ultrastructure and carbohydrate composition of gastroliths from Astacidae, Cambaridae and Parastacidae freshwater crayfish (Crustacea, De…
2012
21 pages; International audience; Crustaceans have to cyclically replace their rigid exoskeleton in order to grow. Most of them harden this skeleton by a calcification process. Some decapods (land crabs, lobsters and crayfish) elaborate calcium storage structures as a reservoir of calcium ions in their stomach wall, as so-called gastroliths. For a better understanding of the cyclic elaboration of these calcium deposits, we studied the ultrastructure of gastroliths from freshwater crayfish by using a combination of microscopic and physical techniques. Because sugars are also molecules putatively involved in the elaboration process of these biomineralizations, we also determined their carbohy…
Do native white-clawed crayfish impact macroinvertebrate assemblages in Mediterranean limestone headwaters?
2019
Crayfish are among the largest aquatic macroinvertebrates in rivers and streams. Their trophic ecology is important for the understanding of the functioning of benthic communities. This is relevant in key areas, such as headwaters, as they partly condition the processes occurring downstream. To shed light on the effects of native white-clawed crayfish,Austropotamobius pallipes, on local macroinvertebrate assemblages from running headwaters, a three-month mesocosm-based field study was designed. Collection and subsequent analysis of benthic samples under different crayfish density levels yielded a set of metrics indicative of short-term impacts at general and taxonomic scales. Neither signif…
Invasive crayfish increase habitat connectivity: a case study in a large boreal lake
2013
Several studies have shown that distinct compartments of lake ecosystems are coupled via transportation of organic matter, nutrients and energy across habitat boundaries. Here we evaluate the potential of the invasive signal crayfish (Pacifastacus leniusculus (Dana)) to modify energy pathways in large boreal lakes. Using a stable isotope mixing model and calculation of the isotopic niches we estimated the contribution of different food sources to the diets of crayfish captured from different habitats, and from that inferred their potential to transport energy across the littoral-profundal gradient. The crayfish caught from the littoral area utilized mainly littoral food sources, whereas the…
The effect of two sulphur-containing pesticides, fenitrothion and endosulfan, on glutathione (GSH) content and on GSH S-transferase and gamma-glutamy…
1988
The glutathione (GSH) system of Procambarus clarkii (P.c.), the American red crayfish, is used as a marker of the effects of Fenitrothion (FT) and Endosulfan (ES), organophosphorus and organochlorinated insecticides, respectively. This system has been shown to be sensitive to different heavy metals poisoning, thus it has a double interest as marker for environmental contamination and as a potential source of xenobiotics or their metabolites to humans, since it is being fished commercially. The GSH content of the organ decreased 24 h after treatment with FT. FT promotes a 2-fold induction of GSH S-transferase (GST) activity at 6 h which is followed by a decrease of it at 24 h. The latter coi…
Nikkelin kertyminen täplärapuun (Pacifastacus leniusculus) kahdessa eri lämpötilassa
2017
Kaivostoiminnan aiheuttamat metallipäästöt ovat maailmanlaajuinen ympäristöongelma. Kaivospäästöjen takia metalleja pääsee luontoon ja eliöstöön biosaatavassa vesiliukoisessa muodossa kuten sulfaatteina tai klorideina. Nikkeli on bioakkumuloituva eliöille haitallinen metalli, jota käytetään teollisuuden raaka-aineena ympäri maailmaa. Tässä tutkielmassa tarkasteltiin nikkelin kertymistä täplärapuun (Pacifastacus leniusculus) laboratorio-olosuhteissa kahdella 14 vrk:n altistuskokeella eri nikkelialtistuspitoisuuksilla kahdessa eri lämpötilassa (7 ja 17 °C). Eri testilämpötiloilla pyrittiin selvittämään, onko nikkelin kertyminen riippuvaista vaihtolämpöisen täpläravun aineenvaihduntatasosta. K…
It takes time to see the menu from the body: an experiment on stable isotope composition in freshwater crayfishes
2015
For many applications and ecological studies in which wild individuals are brought to laboratory it would be essential to know accurately how fast novel diet is reflected in composition of different tissues. To study the effects of two different diets on the stable isotope composition of freshwater crayfish muscle and hemolymph, we conducted a three month experiment on noble crayfish (Astacus astacus) and signal crayfish (Pacifastacus leniusculus) by feeding them sweet corn (Zea mays) or Baltic herring (Clupea harengus membras) as novel food. During the experiment, the crayfish were given 0.4 g of selected food daily and the amount consumed was recorded. The samples for the stable isotope a…
Haemolymphatic Parameters in Two Aquaculture Crustacean Species Cherax destructor (Clark, 1836) and Cherax quadricarinatus (Von Martens, 1868)
2022
In the last few years, there has been a notable development in the breeding of freshwater shrimp (astaciculture), which involved various species and in particular, the two Australian Parastacidae species, Cherax destructor and Cherax quadricarinatus. Information about the haemolymphatic parameters of these two species is fragmentary, and filling these gaps becomes important given their importance in aquaculture. Cellular and biochemical parameters were analyzed in both species to create a reference baseline for these parameters to identify the state of welfare or suffering of these animals. The results showed that the total haemocyte count, haemocyte subpopulations, enzymatic activities and…