Freshwater Fishes of North America

2020 ◽  
1995 ◽  
Vol 52 (S1) ◽  
pp. 7-12 ◽  
Author(s):  
David K. Cone ◽  
Richard L. Raesly

Myxobolus rhinichthidis Fantham, Porter and Richardson, 1939 (Myxosporea) is redescribed from longnose dace (Rhinichthys cataractae) in Maryland. Large round plasmodia occurred in the connective tissue of the skin covering the head and opercular regions. Fixed spores are oval in front view and measure 11.5–14.5 μm long, 9.0–10.5 μm wide, and 6.0–7.0 μm thick. The polar capsules are 5.5–7.0 μm long and 3.0–3.5 μm wide. Photomicrographs of formalin-fixed spores document variation in spore size and shape. The report is the first for M. rhinichthidis since the species was described from blacknose dace (Rhinichthys atratulus) in Quebec. An updated list of species of Myxobolus Bütschli, 1882 reported from freshwater fishes in North America is provided. Myxobolus jahnricei Landsberg and Lom, 1991 is considered a junior synonym of Myxobolus filamentus Grinham and Cone, 1990; and Myxobolus lii Desser, 1993 and Myxobolus gibbosus Li and Desser, 1985 are junior synonyms of Myxobolus uvuliferus Cone and Anderson, 1977.


1992 ◽  
Vol 70 (11) ◽  
pp. 2247-2259 ◽  
Author(s):  
Nicholas E. Mandrak ◽  
E. J. Crossman

The present-day distributions of 117 native freshwater fishes in Ontario have been shaped by processes active following the Wisconsinan glacial period, 80 000–10 000 years before present. During this glacial period, these species survived in unglaciated réfugia. To understand the processes that resulted in the recolonization of Ontario by fishes following the last glacial period, the refugial areas occupied by each species were determined using a refugial index, and glacial water bodies used as dispersal routes were identified. The refugial origins of the Ontario populations of 91 species were resolved. Seventy-two species resided in the Mississippian refugium, 13 species in the Atlantic Coastal refugium, 4 species in dual Atlantic Coastal – Mississippian refugia, 1 species in a Missourian refugium, and 1 species in Atlantic Coastal, Mississippian, and Missourian refugia. These conclusions differed significantly from those of other studies. Five general patterns were identified from the distributions of 104 species. In addition, there are 13 species that do not fit any of the general patterns. Most species with similar distributions in Ontario shared the same refugia and dispersal routes in eastern North America, therefore it is hypothesized that historical processes were important in shaping the present-day distributions of Ontario freshwater fishes.


2017 ◽  
Vol 6 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Cassandra Docherty ◽  
Jonathan Ruppert ◽  
Tyana Rudolfsen ◽  
Andreas Hamann ◽  
Mark Poesch

ABSTRACT Outside of anadromous salmonids and a few endangered species, the biology of native freshwater fishes of western North America is poorly known. What do we need to know to effectively manage native species and avoid decline and extinction? A recent analysis of the role of science in the Pacific salmon controversy outlines a clear framework for biological evaluation and management of native species. This framework has three components: (1) determine the status of populations based on genetic and ecological variation, (2) identify and quantify threats to populations, and (3) determine actions to alleviate threats and promote conservation of populations.We use our studies of leatherside chub <em>Gila copei</em> (also known as <em>Snyderichthys copei</em>), a small cyprinid native to the Bonneville basin and upper Snake River drainage, as a case study to illustrate the application of this research and management framework. Recent surveys have revealed dramatic reductions in range of leatherside chub over the last 50 years. Genetic, morphometric, and ecological studies all indicate that leatherside chub comprise two distinct species. Leatherside chub is threatened by both habitat degradation and introduced brown trout <em>Salmo trutta</em>, and the interaction between these two threats exacerbates negative effects.We conclude by showing how studies of leatherside chub can inform and influence management, conservation, and habitat restoration activities.


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