scholarly journals Spawning activity of European grayling ( Thymallus thymallus ) driven by interdaily water temperature variations: Case study Gr. Mühl River/Austria

Author(s):  
Christoph Hauer ◽  
Günther Unfer
Hydrobiologia ◽  
2020 ◽  
Author(s):  
Ruben Alexander Pettersen ◽  
Claudia Junge ◽  
Kjartan Østbye ◽  
Tor Atle Mo ◽  
Leif Asbjørn Vøllestad

Abstract Understanding how populations are structured in space and time is a central question in evolutionary biology. Parasites and their hosts are assumed to evolve together, however, detailed understanding of mechanisms leading to genetic structuring of parasites and their hosts are lacking. As a parasite depends on its host, studying the genetic structure of both parasite and host can reveal important insights into these mechanisms. Here, genetic structure of the monogenean parasite Gyrodactylus thymalli and its host the European grayling (Thymallus thymallus) was investigated in 10 tributaries draining into the large Lake Mjøsa in Norway. The population genetic structure of spawning grayling was studied using microsatellite genotyping, while G. thymalli was studied by sequencing a mitochondrial DNA gene (dehydrogenase subunit 5). Two main genetic clusters were revealed in grayling, one cluster comprising grayling from the largest spawning population, while the remaining tributaries formed the second cluster. For both taxa, some genetic differentiation was observed among tributaries, but there was no clear isolation-by-distance signature. The structuring was stronger for the host than for the parasite. These results imply that moderate to high levels of gene flow occur among the sub-populations of both taxa. The high parasite exchange among tributaries could result from a lack of strong homing behavior in grayling as well as interactions among individual fish outside of the spawning season, leading to frequent mixing of both host and parasite.


Caryologia ◽  
1988 ◽  
Vol 41 (3-4) ◽  
pp. 245-249 ◽  
Author(s):  
M. Kalat ◽  
B. Mayr ◽  
P. Rab ◽  
W. Schleger

2014 ◽  
pp. 22-30
Author(s):  
A. Khandozhivska ◽  
◽  
S. Krazhan ◽  
A. Mruk ◽  
S. Koba ◽  
...  

2019 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Ervany Eshmat N, Abdul Manan

Abstract The humpback grouper (Cromileptes altivelis) is one of the fishery commodities with high economic value in both local and international markets. The price of humpback grouper can reach Rp. 200,000 - Rp. 400,000 / kilogram in the local market. The humpback grouper is potentially to be developed in most coastal areas of Indonesia. The conditions of water quality have a very important role for the success of fish culture of humpback grouper. To that end, monitoring and management of water quality are necessary in fish culture. The purpose of this case study is to determine the water quality conditions on humpback grouper culture in BBAP, Situbondo. The study was conducted on 16 January until 16 February 2012. The study method use descriptive method. From the results of water quality analysis, the water in humpback grouper broodstock ponds (I1 and I2) is no smell, no colour water, temperature 26.1-30 oC, salinity 27-35 ppt, dissolved oxygen 3.3-3.9 ppm, ammonia levels <0.001-0.22 ppm, nitrite levels 0.0075-0.085 ppm, alkalinity 110-120 ppm and pH 7.94-8.18. The water in humpback grouper hatchery ponds (B1 and B2) is no smell, green colour water, temperature 26.7-29.3 oC, salinity 27-34 ppt, dissolved oxygen 2.7-3.7 ppm, ammonia levels 0.0781-0.28 ppm, nitrite levels 0.0225-3.3305 ppm, alkalinity 94-126 ppm, and pH 7.14-7.81.


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