Pub Date : 2020-04-15DOI: 10.5869/fc.2020.v25-1.039
J. Jussila, L. Edsman
The spreading of the alien signal crayfish (Pacifastacus leniusculus) is posing an ongoing threat to native European crayfish species in Fennoscandia, like the native noble crayfish (Astacus astacus). The signal crayfish is commonly a chronic carrier of the crayfish plague (Aphanomyces astaci), thus, in addition to being more competitive than noble crayfish, it also has a competitive advantage in this disease over the noble crayfish. The challenges rising from the introduction of the alien signal crayfish to Sweden, Finland and finally also Norway, are similar in nature. The licensed and unlicensed spreading of this species also has a similar history in these countries. In this paper we describe some of the patters of the spread of alien signal crayfish and highlight the detrimental nature of an alien crayfish, accompanied by a highly virulent disease, to native Fennoscandian crayfish and also to native Fennoscandian ecosystems. A halt to the further spreading of alien signal crayfish in Fennoscandia is the only means to ensure successful conservation outcomes for the noble crayfish.
{"title":"Relaxed attitude towards spreading of alien crayfish species affects protection of native crayfish species: case studies and lessons learnt from a Fennoscandian viewpoint","authors":"J. Jussila, L. Edsman","doi":"10.5869/fc.2020.v25-1.039","DOIUrl":"https://doi.org/10.5869/fc.2020.v25-1.039","url":null,"abstract":"\u0000 The spreading of the alien signal crayfish (Pacifastacus leniusculus) is posing an ongoing threat to native European crayfish species in Fennoscandia, like the native noble crayfish (Astacus astacus). The signal crayfish is commonly a chronic carrier of the crayfish plague (Aphanomyces astaci), thus, in addition to being more competitive than noble crayfish, it also has a competitive advantage in this disease over the noble crayfish. The challenges rising from the introduction of the alien signal crayfish to Sweden, Finland and finally also Norway, are similar in nature. The licensed and unlicensed spreading of this species also has a similar history in these countries. In this paper we describe some of the patters of the spread of alien signal crayfish and highlight the detrimental nature of an alien crayfish, accompanied by a highly virulent disease, to native Fennoscandian crayfish and also to native Fennoscandian ecosystems. A halt to the further spreading of alien signal crayfish in Fennoscandia is the only means to ensure successful conservation outcomes for the noble crayfish.","PeriodicalId":29940,"journal":{"name":"Freshwater Crayfish","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46905259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. DiStefano, J. Westhoff, Christopher J. Rice, A. Rosenberger
The saddleback crayfish, Faxonius medius (Faxon, 1884), is endemic to a single drainage in eastern Missouri, USA, that is affected by heavy metals mining, and adjacent to a rapidly-expanding urban area. We studied populations of F. medius in two small streams for 18 months to describe the annual reproductive cycle and gather information about fecundity, sex ratio, size at maturity, and size-class structure. We also obtained information about the species’ density at supplemental sites. The species, though rare in a geographic context, is locally abundant; we captured a monthly average of more than 75 F. medius from each of the two study populations. Densities of F. medius were high relative to several sympatric species of Faxonius Cope, 1872 and Cambarus Erichson, 1846. The species exhibited traits of an r-strategist life history; it was relatively short-lived and early to maturity. Its fecundity and egg size were comparable to Ozark congeners. Breeding season occurred in autumn, perhaps extending into early winter. Egg brooding occurred primarily in April. Young-of-year first appeared in samples in June. We estimated that these populations contained 2 to 3 size-classes, and most individuals became sexually mature in their first year of life. Life history information presented herein will be important for future conservation efforts.
{"title":"Life History of the Endemic Saddleback Crayfish, Faxonius medius (Faxon, 1884), (Decapoda: Cambaridae) in Missouri, USA","authors":"R. DiStefano, J. Westhoff, Christopher J. Rice, A. Rosenberger","doi":"10.5869/FC.2019.V24-1.1","DOIUrl":"https://doi.org/10.5869/FC.2019.V24-1.1","url":null,"abstract":"\u0000 The saddleback crayfish, Faxonius medius (Faxon, 1884), is endemic to a single drainage in eastern Missouri, USA, that is affected by heavy metals mining, and adjacent to a rapidly-expanding urban area. We studied populations of F. medius in two small streams for 18 months to describe the annual reproductive cycle and gather information about fecundity, sex ratio, size at maturity, and size-class structure. We also obtained information about the species’ density at supplemental sites. The species, though rare in a geographic context, is locally abundant; we captured a monthly average of more than 75 F. medius from each of the two study populations. Densities of F. medius were high relative to several sympatric species of Faxonius Cope, 1872 and Cambarus Erichson, 1846. The species exhibited traits of an r-strategist life history; it was relatively short-lived and early to maturity. Its fecundity and egg size were comparable to Ozark congeners. Breeding season occurred in autumn, perhaps extending into early winter. Egg brooding occurred primarily in April. Young-of-year first appeared in samples in June. We estimated that these populations contained 2 to 3 size-classes, and most individuals became sexually mature in their first year of life. Life history information presented herein will be important for future conservation efforts.","PeriodicalId":29940,"journal":{"name":"Freshwater Crayfish","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48300104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-28DOI: 10.5869/FC.2019.V24-1.39
Sean M. Hartzell
Sexual dichromatism is a common phenomenon among animal taxa and consists of differing coloration between sexes in a species. Specimens of the crayfish Faxonius rusticus (Girard) typically have a distinct “rusty” red spot on each side of the cephalothorax. These spots can display variation in both redness and size among specimens; however, little work appears to have been done examining variation in this trait. As a means of investigating possible sexual differences in the color and relative spot size (RSS) of the “rusty” spot in F. rusticus, this work utilized digital image analysis techniques to quantify the color and size of spots in a population of this species. Analyses revealed no difference in RSS between sexes; however, spots of females were significantly redder than those of males. Sexual dichromatism in the spot color of F. rusticus in this population could be relevant to mate discrimination during mating; however, this or other possible functions of this sexual color difference will need to be examined by behavioral studies.
{"title":"Sexual Dichromatism of “Rusty” Spots in a Population of Faxonius rusticus (Girard)","authors":"Sean M. Hartzell","doi":"10.5869/FC.2019.V24-1.39","DOIUrl":"https://doi.org/10.5869/FC.2019.V24-1.39","url":null,"abstract":"\u0000 Sexual dichromatism is a common phenomenon among animal taxa and consists of differing coloration between sexes in a species. Specimens of the crayfish Faxonius rusticus (Girard) typically have a distinct “rusty” red spot on each side of the cephalothorax. These spots can display variation in both redness and size among specimens; however, little work appears to have been done examining variation in this trait. As a means of investigating possible sexual differences in the color and relative spot size (RSS) of the “rusty” spot in F. rusticus, this work utilized digital image analysis techniques to quantify the color and size of spots in a population of this species. Analyses revealed no difference in RSS between sexes; however, spots of females were significantly redder than those of males. Sexual dichromatism in the spot color of F. rusticus in this population could be relevant to mate discrimination during mating; however, this or other possible functions of this sexual color difference will need to be examined by behavioral studies.","PeriodicalId":29940,"journal":{"name":"Freshwater Crayfish","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44080892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-28DOI: 10.5869/FC.2019.V24-1.43
A. Richardson
Body sizes (overall length) of 125 Australian and 230 North American freshwater crayfish were extracted from the literature in order to compare the two major radiations of freshwater crayfish. The size distribution of Australian species is strongly skewed to the right and contains at least 13 species that exceed the maximum size of North American crayfish, however the median size class (74 mm) is the same for both faunas. When the burrowing habits of each species are overlain on the distribution, the Australian fauna is shown to have a higher proportion of primary burrowers, and these are significantly smaller than North American primary burrowers. These differences are discussed in terms of the perceived absence of large predators in Australia, and the long term drying and unpredictability of the Australian climate, but no firm causes can be deduced.
{"title":"Body Size in Freshwater Crayfish: An Intercontinental Comparison","authors":"A. Richardson","doi":"10.5869/FC.2019.V24-1.43","DOIUrl":"https://doi.org/10.5869/FC.2019.V24-1.43","url":null,"abstract":"\u0000 Body sizes (overall length) of 125 Australian and 230 North American freshwater crayfish were extracted from the literature in order to compare the two major radiations of freshwater crayfish. The size distribution of Australian species is strongly skewed to the right and contains at least 13 species that exceed the maximum size of North American crayfish, however the median size class (74 mm) is the same for both faunas. When the burrowing habits of each species are overlain on the distribution, the Australian fauna is shown to have a higher proportion of primary burrowers, and these are significantly smaller than North American primary burrowers. These differences are discussed in terms of the perceived absence of large predators in Australia, and the long term drying and unpredictability of the Australian climate, but no firm causes can be deduced.","PeriodicalId":29940,"journal":{"name":"Freshwater Crayfish","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42316281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-28DOI: 10.5869/FC.2019.V24-1.15
A. Richardson, T. S. Walsh
An on-going opportunistic tagging program marked almost 600 giant freshwater crayfish, Astacopsis gouldi, between 22-222 mm carapace length from 123 localities on 62 rivers in Tasmania since 1998. Eighty animals were recaptured once, 50 more than once, and the longest period between initial and latest capture was 8 years. These data were analysed to examine differences in size and growth between the sexes, between the disjunct eastern and western ranges of the species, and between catchments on nutrient-poor and nutrient-rich rocks. Male animals were heavier per unit length than females, as were animals from the western part of the range compared to the naturally disjunct eastern range. Males grew slightly faster than females. Animals from a catchment underlain by nutrient-poor quartzite rocks grew more slowly than those in a neighbouring catchment on richer dolerite. Individual growth histories varied considerably and suggest that there may be fast-growing and slow-growing animals within the population.
{"title":"Geographical Variation in the Giant Freshwater Crayfish, Astacopsis gouldi: Deductions from a Large Opportunistic Database","authors":"A. Richardson, T. S. Walsh","doi":"10.5869/FC.2019.V24-1.15","DOIUrl":"https://doi.org/10.5869/FC.2019.V24-1.15","url":null,"abstract":"\u0000 An on-going opportunistic tagging program marked almost 600 giant freshwater crayfish, Astacopsis gouldi, between 22-222 mm carapace length from 123 localities on 62 rivers in Tasmania since 1998. Eighty animals were recaptured once, 50 more than once, and the longest period between initial and latest capture was 8 years. These data were analysed to examine differences in size and growth between the sexes, between the disjunct eastern and western ranges of the species, and between catchments on nutrient-poor and nutrient-rich rocks. Male animals were heavier per unit length than females, as were animals from the western part of the range compared to the naturally disjunct eastern range. Males grew slightly faster than females. Animals from a catchment underlain by nutrient-poor quartzite rocks grew more slowly than those in a neighbouring catchment on richer dolerite. Individual growth histories varied considerably and suggest that there may be fast-growing and slow-growing animals within the population.","PeriodicalId":29940,"journal":{"name":"Freshwater Crayfish","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48927254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-28DOI: 10.5869/FC.2019.V24-1.33
P. Hamr, M. Hoel, Kathryn L. Eales
The white morph of Faxonius propinquus was first identified and described by Dunham and Jordan. They subsequently documented the presence and geographic distribution of other species in Lake Simcoe, including two additional colour morphs of F. propinquus (Dunham et al. 1979). Since then, no further research has been conducted on these populations, even though the lake has now been invaded by the introduced rusty crayfish (Faxonius rusticus). The present study documents the decline and most recent distribution of the F. propinquus colour morphs and the other native species, Faxonius virilis, which also appears to display several unusual colour morphs in Lake Simcoe. The decline of the various colour morphs of F. propinquus, as well as the impact of the F. rusticus expansion in the lake, were assessed through surveys from 2015 to 2018. The significance of the results is discussed with respect to the conservation status and the future management of native crayfishes in Lake Simcoe.
{"title":"The Distribution and Conservation Status of the White Colour Morph of Faxonius propinquus (Northern Clearwater Crayfish) in Lake Simcoe, Ontario, Canada","authors":"P. Hamr, M. Hoel, Kathryn L. Eales","doi":"10.5869/FC.2019.V24-1.33","DOIUrl":"https://doi.org/10.5869/FC.2019.V24-1.33","url":null,"abstract":"\u0000 The white morph of Faxonius propinquus was first identified and described by Dunham and Jordan. They subsequently documented the presence and geographic distribution of other species in Lake Simcoe, including two additional colour morphs of F. propinquus (Dunham et al. 1979). Since then, no further research has been conducted on these populations, even though the lake has now been invaded by the introduced rusty crayfish (Faxonius rusticus). The present study documents the decline and most recent distribution of the F. propinquus colour morphs and the other native species, Faxonius virilis, which also appears to display several unusual colour morphs in Lake Simcoe. The decline of the various colour morphs of F. propinquus, as well as the impact of the F. rusticus expansion in the lake, were assessed through surveys from 2015 to 2018. The significance of the results is discussed with respect to the conservation status and the future management of native crayfishes in Lake Simcoe.","PeriodicalId":29940,"journal":{"name":"Freshwater Crayfish","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46581975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-28DOI: 10.5869/FC.2019.V24-1.23
Lauren Kong, Alex Ballinger, C. Bonvillain
The majority of Louisiana’s wild crayfish landings are harvested from the Atchafalaya River Basin (ARB) during floodplain inundation from the annual flood pulse. Spatial and temporal heterogeneity in ARB physicochemical characteristics are associated with flood pulse characteristics and floodplain inundation, and extensive areas of the ARB experience environmental hypoxia (dissolved oxygen [DO] < 2.0 mg·L-1) for several weeks to months during the annual flood pulse. The purpose of this research was to evaluate the effects of flood pulse characteristics and physicochemistry on harvested crayfish populations at 14 sites in the ARB that were sampled biweekly during the 2016 and 2017 crayfish seasons. Despite dissimilar 2016 and 2017 flood pulse characteristics, red swamp crawfish Procambarus clarkii and southern white river crawfish P. zonangulus carapace length and CPUE were similar between sample years. Comparisons of P. clarkii populations among physicochemical location groupings indicated that DO concentration, particularly chronically hypoxic water, is the principal abiotic variable influencing P. clarkii population characteristics. Although not significant, normoxic locations produced larger crayfish and yielded higher CPUE values for the majority of both crayfish seasons. Furthermore, hemolymph protein concentrations in P. clarkii from normoxic areas were significantly and consistently higher than individuals from chronically hypoxic locations.
{"title":"Flood pulse characteristics and physicochemical influences on harvested Procambarus clarkii and Procambarus zonangulus populations in the Atchafalaya River basin, Louisiana","authors":"Lauren Kong, Alex Ballinger, C. Bonvillain","doi":"10.5869/FC.2019.V24-1.23","DOIUrl":"https://doi.org/10.5869/FC.2019.V24-1.23","url":null,"abstract":"\u0000 The majority of Louisiana’s wild crayfish landings are harvested from the Atchafalaya River Basin (ARB) during floodplain inundation from the annual flood pulse. Spatial and temporal heterogeneity in ARB physicochemical characteristics are associated with flood pulse characteristics and floodplain inundation, and extensive areas of the ARB experience environmental hypoxia (dissolved oxygen [DO] < 2.0 mg·L-1) for several weeks to months during the annual flood pulse. The purpose of this research was to evaluate the effects of flood pulse characteristics and physicochemistry on harvested crayfish populations at 14 sites in the ARB that were sampled biweekly during the 2016 and 2017 crayfish seasons. Despite dissimilar 2016 and 2017 flood pulse characteristics, red swamp crawfish Procambarus clarkii and southern white river crawfish P. zonangulus carapace length and CPUE were similar between sample years. Comparisons of P. clarkii populations among physicochemical location groupings indicated that DO concentration, particularly chronically hypoxic water, is the principal abiotic variable influencing P. clarkii population characteristics. Although not significant, normoxic locations produced larger crayfish and yielded higher CPUE values for the majority of both crayfish seasons. Furthermore, hemolymph protein concentrations in P. clarkii from normoxic areas were significantly and consistently higher than individuals from chronically hypoxic locations.","PeriodicalId":29940,"journal":{"name":"Freshwater Crayfish","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48341768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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