Biological characteristics of trout (Salmo trutta L.) smolts grown in river Mołstowa catchment area

Abstract

The paper presents the following biological characters of trout (Salmo trutta L) smolts grown under natural condi tions of the river Molstowa: length and weight distribution, age, sex ratio, and gonad maturity stage.

Age structure of the smolts of the migratory morphotype of the brown trout (Salmo trutta m. trutta L., 1758) from the Gowienica River

“…6. In the studies of Chelkowski (1978) and Chelkowska (1982) "small" edge increment in age groups ranged within 25-31 and 14-51 mm, while in the present study it was 16-44 mm. Similar values of "big" edge increments are attained by the smolts of the same age group (I+).…”

“…In the course of the present study a similar analysis of the scales was performed involving the distribution of the edge increments. The presently studied ma terial did not contain smolts of the age group O+, similarly as in the material of Chelkowski (1978) and Chelkowski and Chelkowska (1982). On the other hand smolts I+ and 2+ oc curred in both materials.…”

“…According to Chelkowski (1978), Chelkowski and Chelkowska (1982), determination of the real age of smolts requires counting of the annual rings on the scales and analysis of the edge increments "dk". In the course of the present study a similar analysis of the scales was performed involving the distribution of the edge increments.…”

“…weight 54.0 g; scale radii: S 1 = 0.41 mm; S2 = 0.85 mm; S = 1.01 mm); real age 2 years edge increments occurrence was determined for the smolts stud ied. Following Backiel (1962), Sych (1967b ), Chelkowski (1978), and Chelkowski and Chelkowska (1982)-the edge increment was defined as a dif ference between the length of fish measured after the capture and the fish length determined based on the last annual ring using the back-reading method.…”

Frequency of occurrence of acanthocephalans (Acanthocephala) and cestodes (Cestoda) in alimentary tracts of the sea trout smolts (Salmo trutta m. trutta) grown in the drainage area of the river Rega and their impact on fish condition

“…1. A total of 24 7 alimentary tracts were analyzed from one-, two-and three year-old smolts (Chelkowski 1978;Chelkowski et al 1982) .. Acanthocephalans attach to the intestinal wall with hooks situated on a proboscis. In the place of attachment there is a hyperaemia indicating inflammation of mucosa and dam age of intestinal wall.…”