Search results for "crayfish"
showing 10 items of 67 documents
An alien ectosymbiotic branchiobdellidan (Annelida: Clitellata) adopting exotic crayfish: a biological co-invasion with unpredictable consequences
2015
Invasive alien species present a global threat to biodiversity, particularly where pathogens and symbionts are involved. Branchiobdellidans are clitellate annelids with an obligate ectosymbiotic association primarily on astacoidean crayfish. There are several examples of branchiobdellidan species adopting a geographically exotic host where endemic and exotic crayfishes cohabit the same water body. The first records of a western North American branchiobdellidan, Xironogiton victoriensis , adopting the eastern North American crayfish, Procambarus clarkii , in 2 river basins in Spain provide further evidence of the ectosymbionts’ tolerance to adopt an exotic host. Given worldwide translocation…
Effect of sublethal exposure to mercury in the biochemical composition of hepatopancreas in Procambarus clarkii during the recovery after starvation
1993
Abstract Freshwater crayfish undergo seasonal periods of starvation. The hepatopancreas is the main energetic-storage organ in this animal. An adequate replenishment of energetic reserves after these periods of fasting is critical for the proper growth and reproduction in this species. Mercury compounds enter the biological environment from natural discharges and anthropogenic sources. Mercuric chloride is one of the most toxic metallic salts found in polluted waters. In these studies, we report the effect of mercuric chloride in the biochemical composition of crayfish hepatopancreas during the recovery period after prolonged starvation. Adult intermolt crayfish (P. clarkii) were kept starv…
Comparison of Two Chemicals for Removing an Entocytherid (Ostracoda: Crustacea) Species from Its Host Crayfish (Cambaridae: Crustacea)
2011
Entocytherids are epifauna on larger crustaceans. We assessed the effectiveness of chlorobutanol and carbonated water for removing entocytherid, Ankylocythere sinuosa, from crayfish, Procambarus clarkii. This was done using different exposure times and by assessing entocytherid and crayfish survival, together with the number of entocytherids removed. According to our results, chlorobutanol submersion of crayfishes in shorter time periods is more effective for removing entocytherids without killing the crayfish host. However, carbonated water submersion is better to extract larger amounts of living entocytherids. Finally, both chemicals are appropriate tools to establish standardised protoco…
Degradation and acute toxicity of Methidathion and Trichlorfon onProcambarus clarkii,in experimental conditions
1991
Routine applications of organophosphate pesticides may adversely affect many nontarget organisms. Static toxicities in mature crayfish Procambarus clarkii were determined, in laboratory, for two organophosphate insecticides using 24, 48, 72 and 96‐h static tests. Three groups of 10 crayfish were exposed to 0.75 to 6 ppm for Trichlorfon and 0.2 to 0.9 ppm for Methidathion. The 24 to 96‐h LC50 values for Trichlorfon and Methidathion were from 5.14–0.99 ppm and 0.73–0.28 ppm respectively. Studies of degradation of Methidathion and Trichlorfon have been made using 1 ppm for Methidathion and 0.1 ppm for Trichlorfon. Both insecticides were degradated gradually until 96‐h. Results show that Methid…
The influence of environmental factors on abundance and prevalence of a commensal ostracod hosted by an invasive crayfish: are ‘parasite rules’ relev…
2014
Summary Symbiosis represents a widespread and successful lifestyle, but research on symbiotic associations has been mainly focused on parasites. Three general patterns in parasite ecology have been proposed: (i) aggregation, (ii) positive and tight correlation between mean symbiont abundance and its variance and (iii) positive correlation between abundance and prevalence of symbionts. The factors affecting abundance and prevalence within symbiont species can be grouped into host features and environmental conditions. According to research in parasite ecology, environmental conditions seem to play a minor role. We investigated whether the three most recognised parasite patterns were also evi…
Beyond the mean: A comparison of trace- and macroelement correlation profiles of two lacustrine populations of the crayfish Procambarus clarkii
2018
In invertebrate biomonitors of chemical pollution, emphasis has been generally given to mean accumulation patterns and how they reflect varying environmental levels of contamination. Intra-population variability, and how it relates with individual phenotypic traits, has received less attention. Here, a set of analytes including trace elements (B, Ba, Cd, Cr, Cu, Fe, Li, Mn, Ni, Pb, Sr, V, and Zn), macroelements (C, Ca, K, Mg, N, Na), and carbon and nitrogen stable isotopes (δ13C and δ15N) was measured in two populations of the crayfish Procambarus clarkii from Lake Trasimeno and Lake Bolsena (Central Italy). The influence of location, sex, body size, and condition factor was assessed; in ad…
Individual and population-scale carbon and nitrogen isotopic values of Procambarus clarkii in invaded freshwater ecosystems
2022
Este artículo contiene 16 páginas, 1 figura, 1 tablas.
Spatial Mark-Recapture Method in the Estimation of Crayfish Population Size
1995
The mark-recapture method is considered for estimation of population size of slowly moving animals like crayfish. The Petersen type estimator for closed population is generalized for situations where recaptures are spatially dependent between the capture sites, and its variance approximation is derived using point processes as models for the population. The method of quadratic forms is suggested to be used as variance estimator. Finally, a trapping design is proposed where onc trap at recapture is replaced by four adjacent traps. A simulation experiment is performed to explain the robusticity of the new trapping design against movements of animals.
Infection with acanthocephalans increases the vulnerability of Gammarus pulex (Crustacea, Amphipoda) to non-host invertebrate predators.
2008
SUMMARYPhenotypic alterations induced by parasites in their intermediate hosts often result in enhanced trophic transmission to appropriate final hosts. However, such alterations may also increase the vulnerability of intermediate hosts to predation by non-host species. We studied the influence of both infection with 3 different acanthocephalan parasites (Pomphorhynchus laevis, P. tereticollis, and Polymorphus minutus) and the availability of refuges on the susceptibility of the amphipod Gammarus pulex to predation by 2 non-host predators in microcosms. Only infection with P. laevis increased the vulnerability of amphipods to predation by crayfish, Orconectes limosus. In contrast, in the ab…
Biological responses to high-frequency sound in a freshwater crayfish, Cherax quadricarinatus
2023
Anthropogenic noise is recognised as an important environmental stressor that can have longterm negative consequences on species. In recent years, there has been increasing attention to the potential negative impact of noise pollution on species, with great concern for the importance of impacts on aquatic animal life. This study examined the effects of acoustic stress on the biochemical parameters of the freshwater crayfish Cherax quadricarinatus. The experiment was conducted in a tank equipped with an audio and video recording system using ten groups (five control and five test) of three adult crayfish (30 animals in total). The animals in the test group were exposed to acoustic signals [a…