A Comparison of Pneumatic and Hand Stripping of Whitefish (Coregonus lavaretus) Eggs for Artificial Reproduction.

Radosław Kajetan Kowalski,Beata Sarosiek,Joanna Grudniewska,Mirosław Szczepkowski,Stefan Dobosz,Beata Irena Cejko

doi:10.3390/ani10010097

Abstract

Simple SummaryThis paper describes a technique of pneumatic stripping of whitefish (Coregonus lavaretus) eggs with the use of oxygen, nitrogen, and air. This study demonstrates that pneumatic stripping allows the collection of high-quality whitefish eggs. Moreover, we found that gas flow rates should not exceed 0.5 L∙min−1 to minimize post-spawning mortality in whitefish. The eggs obtained by pneumatic stripping using oxygen, nitrogen, or air had high hatching rates. We assumed that air stripping is a promising approach for improvement of the whitefish stripping procedure.We describe the technique of pneumatic stripping of whitefish (Coregonus lavaretus) eggs with the use of oxygen, nitrogen, and air. Eggs obtained via the traditional method (by pressing the abdominal surfaces) served as a control group. It was established that the gas flow rate during pneumatic stripping should not exceed 0.5 L∙min−1, since higher air flow resulted in increased post-spawning mortality. The pneumatic stripping method of egg collection was no faster than hand stripping; however, the time required per female was more consistent. It was found that the pH of the ovarian fluid obtained during hand and pneumatic stripping was not related to the success rate of fertilization. Pneumatic stripping resulted in a higher quality of collected eggs and a higher and more consistent hatching rate as compared with the hand-stripped samples, regardless of the gas used. The results presented here lead us to recommend the pneumatic method for obtaining eggs from whitefish, since it is a simple, reproducible method and improves the reproductive performance and developmental success of the fish eggs.

Highlights

The whitefish (Coregonus lavaretus) belongs to the Salmonidae family, and is one of the most valuable species of freshwater ichthyofauna
−1 significant differences were observed between hand and pneumatic stripping in terms of the time of and air) with a flow rate of approximately 0.5 L min can be successfully utilized for this procedure
The fertilization rate at the eyed stage and hatching rate was higher in the pneumatic stripping group, regardless of the gas used for egg collection, and we found that the hand-stripped group exhibited the highest variability in fertilization success

Summary

Introduction

The whitefish (Coregonus lavaretus) belongs to the Salmonidae family, and is one of the most valuable species of freshwater ichthyofauna. Work focused on increasing the egg developmental success in whitefish has not yet been done These activities are essential, because the conservation of aquaculture is a very important tool for the restitution and support of fish species that are in danger of extinction. Despite the fact that the wild population of whitefish is decreasing, the production and sale of whitefish have increased in Europe from 2344 t in 2000 to 5310 t in 2017 [13] and this species has recently attracted considerable interest from fish producers [14]. This fish undoubtedly represents high value to consumers, and production of this species could offer a valuable addition to commercial trout-breeding facilities [15]

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