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Timecourse of oocyte development in saithe Pollachius virens
J E Skjaeraasen1, J A Devine1, J A Godiksen1
1Institute of Marine Research and Hjort Centre for Marine Ecosystem Dynamics, N-5817, Bergen, Norway.
Journal of Fish Biology
|October 14, 2016
Summary
This study monitored North Sea saithe (Pollachius virens) reproduction, detailing oocyte development, sex steroid changes, and fecundity. Saithe spawning occurs from February to March, with egg size decreasing throughout the season.
Area of Science:
- Marine Biology
- Fish Reproduction
- Endocrinology
Background:
- North Sea saithe (Pollachius virens) reproductive biology requires detailed investigation.
- Understanding reproductive cycles is crucial for fisheries management and conservation efforts.
Purpose of the Study:
- To monitor wild-caught North Sea saithe for growth, sex steroid profiles, and oocyte development.
- To measure egg size and group fecundity during the spawning season.
- To validate sex steroid levels in P. virens.
Main Methods:
- Monitoring of wild-caught North Sea saithe (Pollachius virens) during pre-spawning and spawning.
- Analysis of sex steroid profiles (oestradiol-17β, testosterone, 11-ketotestosterone).
- Measurement of oocyte size, egg size, and group fecundity; histological examination of gonads.
Main Results:
- Vitellogenesis began in late October-early November, with rapid oocyte growth until February spawning.
- Sex steroid concentrations increased pre-spawning and decreased post-spawning.
- Spawning occurred from February 13 to March 29, with mean egg size of 1.18 mm and average fecundity of 0.84 million eggs.
Conclusions:
- The study provides the first validation of sex steroid levels in North Sea saithe.
- Reproductive parameters such as oocyte development, sex steroid profiles, and fecundity were characterized.
- Saithe spawning is characterized by specific oocyte development stages, steroid hormonal changes, and defined spawning periods and egg characteristics.
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