Sexual cycle of white bream, Blicca bjoerkna (Actinopterygii, Cypriniformes, Cyprinidae), from three sites of the lower Oder River (NW Poland) differing in temperature regimes

Abstract

Domagała J., Dziewulska K., Kirczuk L., Pilecka-Rapacz M. 2015. Sexual cycle of white bream, Blicca bjoerkna (Actinopterygii, Cypriniformes, Cyprinidae), from three sites of the lower Oder River (NW Poland) differing in temperature regimes. Acta Ichthyol. Piscat. 45 (3): 285-298.Background. One of the largest European populations of white bream, Blicca bjoerkna (Linnaeus, 1758), can be found in the estuary of the Oder River. This fi sh is not only very abundant in this area but also attains sizes that have no match in other areas of central Europe. In search for the clues behind such reproductive success we decided to study the annual development cycle of gonads of white bream from three sites in the lower Oder River, north-western Poland, differing in temperature regimes (depending on their position and the distance from the discharge outlet of the Dolna Odra Power Plant). Materials and methods. White bream individuals were obtained from the three sites as bycatch of commercial fi shing in 2009 and 2010. Three sites were sampled: (1) the Oder River above the power plant, (2) the warm-water canal with post-cooling water discharged from the power plant, and (3) Lake Dąbie, 20 km below the warm-water canal. The fi sh age was determined as 2+ through 9+. In total, 506 females and 190 males were designated for histological analyses. The analysis of the annual cycle of gonad development was performed in both sexes using histological methods. A standard paraffi n technique and Heidenhain's iron hematoxylin staining were used. Results. In the Oder River, spawning of white bream lasted from early May to late June. In Lake Dąbie, it extended until the beginning of July. The spawn was laid in 2 or 3 portions. In the warm-water canal spawning began one month earlier, in April. The bream males from the thermally unaffected Oder River were ready for reproduction approximately one month earlier than the females and maintained their reproductive potential similarly to the females. Males from the warm-water canal became sexually mature two months earlier (February) than those from the river above the power plant. Conclusion. In waters with elevated temperature, gametogenesis of white bream occurs without problems and the fi sh exhibit a typical pace of growth depending on the temperature. In the perspective of climate warming, white bream will be able to maintain its status of a common species in the natural waters of the region.

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“…The blue bream male finalized spermatogenesis in April, however, the cycle in Lake Dąbie was completed slightly earlier than in the Oder River. The gonad filled with a large amount of spermatozoa was observed during 3 months, a period similar to that in the white bream, although only a few individuals in the studied species retained this stage in this period (Domagała et al, 2015b). The GSI of the analysed males was 5-6 times lower than in the females just before spawning (2 and 12%, respectively).…”

“…In December, the analysed blue bream males reached maturity stage IV and awaited the early spring spawning period. In the winter, the white bream and the common bream have gonads at earlier maturity stages (II or III) and spawning in these species takes place later (Sakun and Butskaya, 1968;Brylińska and Długosz, 1973;Domagała et al, 2015b). The blue bream male finalized spermatogenesis in April, however, the cycle in Lake Dąbie was completed slightly earlier than in the Oder River.…”

“…Histological analysis was performed to determine the developmental stage of the blue bream gonads using the modified 6-grade scales proposed by Domagała et al (2013Domagała et al ( , 2015b (Table 1, Table 2). …”

Spawning phenology of the white bream (Blicca bjoerkna) in the "Dnieper-Orylskiy" Nature Reserve in relation to seasonal temperature dynamic

“…Нерест плоскирки в різних регіонах Європи відбувається майже у подібний період із початку травня до кінця червня, або навіть до початку липняу Польщі (Domagała et al, 2015), Північній Росії (Berg, 1949), Бельгії Kestemont, 1996, 2003), Німеччині (Spratte and Hartmann, 1997;Molls, 1999). Найраніший нерест був зафіксований у Туреччині в квітні (Yılmaz et al, 2012(Yılmaz et al, , 2015Okgerman et al, 2012).…”

Artificial Reproduction of Blue Bream (Ballerus ballerus L.) as a Conservative Method under Controlled Conditions

“…The spawning period can shift to late May if the water does not become warm enough due to low spring air temperatures [5]. The blue bream's annual reproductive cycle description is based on gonad morphology, GSI fluctuations [5] and the gonad histology in fish of both sexes in the annual development cycle [8,9]. This species' reproduction under controlled conditions has not yet been conducted.…”