The glochidia of certain Unionidae (Mollusca) in Nova Scotia and their fish hosts

1975 ◽  
Vol 53 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Michael Wiles

Morphological and morphometric comparisons among adult and glochidial unionids from two Nova Scotian locations showed that Anodonta implicata, A. cataracta cataracta, A. c. fragilis, Elliptio complanatus, and Lampsilis radiata radiata were present. Gravidity studies suggested that fully developed glochidia occur from September to May in Anodonta marsupia, for only 5–6 weeks in June and July in E. complanatus, and perhaps at least from spring to early fall in L. r. radiata. Seven of 12 fish species sampled bore glochidia, which were identified in five host species by comparisons of their shapes and dimensions with those of glochidia from adult clams. Results were as follows: A. c. cataracta in Catostomus commersoni in June only, A. implicata or A. c. cataracta in Gasterosteus aculeatus in May and June, Anodonta sp. in Apeltes quadracus and Pungitius pungitius in June, and E. complanatus in Fundulus diaphanus in June and July. Thus, no relationships between gravidity periods of adult clams and infestation periods of their fish hosts by their glochidia were evident for species of Anodonta.

1974 ◽  
Vol 31 (6) ◽  
pp. 1135-1139 ◽  
Author(s):  
George Hanek ◽  
Kalman Molnar

In 224 fish of nine species from Matamek River system 38 genera of parasites were recovered (12 Protozoa, 3 Monogenea, 6 Digenea, 6 Cestoda, 6 Nematoda, 2 Acanthocephala, 3 Copepoda). Six genera of parasites were noted in Salmo salar, Salvelinus fontinalis harbored 17 genera, S. alpinus 5 genera, Osmerus mordax 4 genera, Anguilla rostrata 9 genera, Catostomus catostomus 8 genera, Apeltes quadracus 1 genus, Gasterosteus aculeatus 12 genera, and Pungitius pungitius 9 genera.


1969 ◽  
Vol 26 (5) ◽  
pp. 1390-1392 ◽  
Author(s):  
E. T. Garside

Collections of fishes from the several bodies of fresh and brackish waters on Sable Island, Nova Scotia (60°06′W, 43°56′N), were composed variously of four euryhaline species: Fundulus heteroclitus (Cyprinodontidae), Gasterosteus wheatlandi, Apeltes quadracus, and Pungitius pungitius (Gasterosteidae). Sight records are reported for Anguilla rostrata (Anguillidae).


1981 ◽  
Vol 59 (12) ◽  
pp. 2394-2395 ◽  
Author(s):  
Gérard J. FitzGerald ◽  
Jean-Denis Dutil

The diet of the black-crowned night heron (Nycticorax nycticorax) feeding in June and July along the southern shore of the St. Lawrence Estuary was composed primarily of the threespine stickleback Gasterosteus aculeatus. Three other sticklebacks, G. wheatlandi, Pungitius pungitius, and Apeltes quadracus occur in areas where the birds feed but were not eaten. It is suggested that differential predation on G. aculeatus may diminish interspecific competition for nest sites where the four stickleback species co-occur on the breeding grounds.


Author(s):  
Tapio Sutela ◽  
Teppo Vehanen ◽  
Pekka Jounela ◽  
Jukka Aroviita

Species-environment relationships were studied between the occurrence of 13 fish and lamprey species and 9 mainly map-based environmental variables of Finnish boreal small streams. A self-organizing map (SOM) analysis showed strong relationships between the fish species and environmental variables in a single model (explained variance 55.9%). Besides basic environmental variables such as altitude, catchment size, and mean temperature, landcover variables were also explored. A logistic regression analysis indicated that the occurrence probability of brown trout, Salmo trutta L., decreased with an increasing percentage of peatland ditch drainage in the upper catchment. Ninespine stickleback, Pungitius pungitius (L.), and three-spined stickleback, Gasterosteus aculeatus L., seemed to benefit from urban areas in the upper catchment. Discovered relationships between fish species occurrence and land-use attributes are encouraging for the development of fish-based bioassessment for small streams. The presented ordination of the fish species in the mean temperature gradient will help in predicting fish community responses to climate change.


1985 ◽  
Vol 63 (4) ◽  
pp. 956-960 ◽  
Author(s):  
D. K. Cone ◽  
M. Wiles

The systematics and zoogeography of Gyrodactylus from gasterosteid fishes (Apeltes quadracus, Culaea inconstans, Pungitius pungitius, Gasterosteus aculeatus, and G. wheatlandi) in North America were examined through a study of museum-held specimens and fresh material collected from localities across Canada. Six species are considered specific to these fishes, namely: G. alexanderi Mizelle and Kritsky, 1967, G. avalonia Hanek and Threlfall, 1969 (syn. G. lairdi Hanek and Threlfall, 1969, G. memorialis Hanek and Threlfall, 1969, G. terranovae Hanek and Threlfall, 1969), G. canadensis Hanek and Threlfall, 1969, G. cameroni Hanek and Threlfall, 1970, G. eucaliae lkezaki and Hoffman, 1957, and an unidentified species resembling G. pungitii Malmberg, 1964. The fauna has striking morphological similarities to that parasitizing the same host fishes in Eurasia. In fact, G. avalonia, G. canadensis, and the unconfirmed species are considered sister species to G. arcuatus Bychowsky, 1933, G. branchicus Malmberg, 1964, and G. pungitii, respectively. The match-ups are considered to have evolved from three lineages that parasitized G. aculeatus and P. pungitius prior to Pleistocene dispersal that resulted in these fishes and their parasites extending over much of the northern hemisphere. Gyrodactylus cameroni from A. quadracus is probably of North American origin and a sister species of G. avalonia. Gyrodactylus alexanderi from Pacific coast G. aculeatus and G. eucaliae from C. inconstans in the continent's central region have ties with a Pacific lineage. The parasites' geographical distributions and possible evolutionary histories since Pleistocene glaciation are discussed.


1984 ◽  
Vol 62 (11) ◽  
pp. 2313-2316 ◽  
Author(s):  
Jocelyn Hudon ◽  
Helga Guderley

The genetic relationships between four species of sticklebacks, Gasterosteus aculeatus Linneaus form trachurus, Gasterosteus wheatlandi Putnam, Pungitius pungitius (Linneaus), and Apeltes quadracus (Mitchill) were estimated by a locus-by-locus analysis of interspecific allozyme variation as well as by a band-counting analysis of soluble proteins in muscle. The locus-by-locus data was analysed both by a qualitative cladistic analysis and by a quantitative phenetic analysis. Both the locus-by-locus analysis and the band-counting analysis generated phylogenies which concord with the previously established relationships among these species. Our analyses indicate that these species have diverged considerably with a genetic identity of only 0.37 between the two congeneric species.


Parasitology ◽  
1974 ◽  
Vol 69 (3) ◽  
pp. 291-300 ◽  
Author(s):  
R. A. Sweeting

The range of fish hosts parasitized by Diplostomum spathaceum was assessed. Natural and experimental levels of infection were compared between host species. The accumulation of eye flukes with age was established in one host – Rutilus rutilus. Development of metacarcariae in lenses of naturally infected Gasterosteus aculeatus throughout the year was compared with that of experimentally infected South African clawed toads, Xenopus laevis, maintained at various temperatures (5–30 °C). The importance of temperature changes to this part of the life-cycle of the parasite is discussed.


2021 ◽  
pp. 1356336X2098588
Author(s):  
Daniel B Robinson ◽  
Nathan Hall ◽  
José da Costa ◽  
Brent Bradford

Due to the overemphasis of traditional sports at the expense of other movement domains in physical education (PE) programmes, there is a need to consider what factors might enable or limit PE teachers’ incorporation of some of these other domains that can support student learning. The focus of this article is on one such marginalized domain – alternative environment activities (AEAs). AEAs can afford students a breadth of opportunities for moderate-to-vigorous physical activity in different environments (i.e. land, snow and ice, water, air) and improve environmental awareness and stewardship. This article reports on a comparative investigation of Nova Scotian (Canadian) and Irish PE teachers’ incorporation of AEAs in their PE programmes. To understand what similarities or differences might exist with respect to these PE teachers’ incorporation of AEAs, along with existing enablers and barriers, a self-selected sample of current PE teachers (Nova Scotia = 53; Ireland = 64) completed a 22-item online questionnaire. Descriptive and inferential statistical analyses were employed to conduct comparisons among the two data sets. PE teachers’ understandings of curricular requirements for AEAs were found to be an issue in both Nova Scotia and Ireland. Reported significant differences include: AEA-related professional development participation; most important factors for deciding not to include AEAs; and feelings of school administrative support towards AEA incorporation. Findings also suggest that various issues may be hindering incorporation of AEAs in PE programmes, and that some of these issues do differ based on where the PE programme is situated.


2021 ◽  
Vol 22 (4) ◽  
pp. 1614
Author(s):  
María Esther Rodríguez ◽  
Ismael Cross ◽  
Alberto Arias-Pérez ◽  
Silvia Portela-Bens ◽  
Manuel Alejandro Merlo ◽  
...  

Cytogenomics, the integration of cytogenetic and genomic data, has been used here to reconstruct the evolution of chromosomes 2 and 4 of Solea senegalensis. S. senegalensis is a flat fish with a karyotype comprising 2n = 42 chromosomes: 6 metacentric + 4 submetacentric + 8 subtelocentric + 24 telocentric. The Fluorescence in situ Hybridization with Bacterial Artificial Chromosomes (FISH-BAC) technique was applied to locate BACs in these chromosomes (11 and 10 BACs in chromosomes 2 and 4, respectively) and to generate integrated maps. Synteny analysis, taking eight reference fish species (Cynoglossus semilaevis, Scophthalmus maximus, Sparus aurata, Gasterosteus aculeatus, Xiphophorus maculatus, Oryzias latipes, Danio rerio, and Lepisosteus oculatus) for comparison, showed that the BACs of these two chromosomes of S. senegalensis were mainly distributed in two principal chromosomes in the reference species. Transposable Elements (TE) analysis showed significant differences between the two chromosomes, in terms of number of loci per Mb and coverage, and the class of TE (I or II) present. Analysis of TE divergence in chromosomes 2 and 4 compared to their syntenic regions in four reference fish species (C. semilaevis, S. maximus, O. latipes, and D. rerio) revealed differences in their age of activity compared with those species but less notable differences between the two chromosomes. Differences were also observed in peaks of divergence and coverage of TE families for all reference species even in those close to S. senegalensis, like S. maximus and C. semilaevis. Considered together, chromosomes 2 and 4 have evolved by Robertsonian fusions, pericentric inversions, and other chromosomal rearrangements mediated by TEs.


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