scholarly journals Occurrence of intersex in wild freshwater fish in Slovenian rivers: a histological evaluation

2016 ◽  
Vol 67 (3) ◽  
pp. 216-222
Author(s):  
Milka Vrecl ◽  
Vlasta Jenčič
Keyword(s):  
Freshwater Fish ◽  
Salmo Trutta ◽  
Testicular Tissue ◽  
Histological Evaluation ◽  
Thymallus Thymallus ◽  
Barbus Barbus ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Rivers And Streams ◽  
Brown Trout Salmo Trutta ◽  
Insight Into

Abstract The aim of this preliminary research was to establish if there are intersex occurrences in wild freshwater fish in Slovenian rivers and streams. In the first study we evaluated all fish species of both sexes obtained from the river Ljubljanica from its source to mouth. In the second study we focused on the rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta m. fario) males from 30 rivers and streams in different parts of Slovenia. The male gonads were histologically assessed for the presence of oocytes to determine the frequency and degree of intersex. Oocytes were found in the testicular tissue of a single grayling (Thymallus thymallus) and in the adipose tissue adjacent to the testis of a single common barbel (Barbus barbus), both from the Ljubljanica. Several cyst-like structures that resemble degenerated presumptive oocytes were also present in several trout testes. This preliminary report is the first of its kind in Slovenia. To gain a better insight into the intersex issue in Slovenia, we plan to regularly biomonitor freshwater pollution by histologically examining fish gonads and, if possible, by determining vitellogenin plasma levels in fish.

scholarly journals Diseases of different aetiologies in salmonids in Ukraine

Biologija ◽  
2020 ◽  
Vol 65 (4) ◽  
Author(s):  
Nаtalia Matvienko ◽  
Maria Maistrenko ◽  
Leonid Buchatsky ◽  
Alexander Didenko
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Fish Farms ◽  
Thymallus Thymallus ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Brown Trout Salmo Trutta ◽  
European Genotype ◽  
First Time ◽  
Natural Water Bodies

The paper contains the results of the studies into the ichthyopathological situation of the invasion and infectious diseases of salmonids carried out by the Ichthyopathology Laboratory of the Institute of Fisheries of Ukraine from 2013 to 2016. The investigated salmonid species included: the rainbow trout Oncorhynchus mykiss, the brown trout Salmo trutta morpha fario, the brook trout Salvelinus fontinalis, and the European grayling Thymallus thymallus. The fish were sampled from aquatculture farms as well as natural water bodies and their diseases included invasive (parasitic) and infectious (viral and bacterial). The most frequently encountered invasions in the brown and brook trout were ciliates: Chilodonella pisci­cola and Apiosoma conicum, Trichodina (in particular T. truttae and T. nigra), Ichtyophthirius multifiliis; monogenea Gy­rodactylus birmani, and diplostoma Diplostomum spathaceum. Aeromonas and Flavobacterium bacteria were isolated from fry and young-of-the-year rainbow trout and brook trout. Y. ruckeri positive samples were isolated from the fish with the signs of yersiniosis. As for viral diseases, IPNV isolates (the first time in Ukraine) of the rainbow trout were first isolated in fish farms in the western regions of Ukraine. A phylogenetic analysis of these IPNV isolates was performed, which showed that they belonged to Sp strain and the European genotype.

An examination of the PCB: lipid relationship among individual fish

1997 ◽  
Vol 54 (5) ◽  
pp. 1031-1038
Author(s):  
C A Stow ◽  
L J Jackson ◽  
J F Amrhein
Keyword(s):  
Salmo Trutta ◽  
Lake Michigan ◽  
Oncorhynchus Tshawytscha ◽  
Lake Trout ◽  
Coho Salmon ◽  
Salvelinus Namaycush ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Strong Linear Correlation ◽  
Brown Trout Salmo Trutta ◽  
The Relationship

We examined data from 1984 to 1994 for five species of Lake Michigan salmonids to explore the relationship between total PCB concentration and percent lipid. When we compared mean species lipid and PCB values, we found a strong linear correlation. When we compared values among individuals, we found modest positive PCB:lipid associations in brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and rainbow trout (Oncorhynchus mykiss) collected during spawning, but positive associations were not apparent among nonspawning individuals. Lake trout (Salvelinus namaycush) exhibited no discernible PCB:lipid relationship. Our results are not incompatible with previous observations that contaminants are differentially partitioned into lipids within a fish, but these results do suggest that lipids are not a major factor influencing contaminant uptake.

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