Fecundity assessment of vendace, Coregonus albula L. from six lakes in Polish Western Pomerania

Vendace acquired for the fecundity analysis originated from six west Pomeranian lakes: Pile (97 specimens), Komorze (41), Drawsko (62), Pełcz (89), Moryńskie (91), and Leśne (70). The fish were caught during commercial catches using anchored gillnets, 24-mm mesh size. Substantial differences were stated in individual biological parameters between fish representing different lakes, even if the dominant age group everywhere were 2+ vendace. The fish of Drawsko Lake showed the highest individual weight and the total length. The highest fecundity was stated in fish from lakes Komorze and Drawsko (7.21-16.85ּ103 and 6.9-22.23ּ103, respectively), whereas in Pełcz Lake this parameter reached the value as low as 1.61-4.12ּ103. All vendace exhibited a high, statistically significant correlation between the absolute fecundity and their total length

Fish management and biogenic levels entered in lakes in groundbait on the example of the Myśla Upper basin

W pracy przedstawiono wartości podstawowych parametrów określających presję wędkarską na 5 jeziorach położonych w zlewni górnej Myśli na Pojezierzu Myśliborskim. Badania przeprowadzono metodą ankietową, rozdając 271 ankiet wędkarskich podczas zakupu zezwoleń do połowu ryb. Ponadto kilkakrotnie w miesiącu przeprowadzono wizje terenowe nad każdym z jezior, w celu określenia liczby wędkujących. W strukturze ryb poławianych przez wędkarzy dominują karpiowate: płoć (31,2%), leszcz (23,5%) i lin (8,3%), z niewielką ilością ryb drapieżnych (szczupak 12,8%, okoń 7,6%, sandacz 3,6% i węgorz 2,1%). Łączny udział ryb karpiowatych wynosi 72,0%, co oznacza, że jeziora mogą znajdować się w stanie dość znacznie posuniętych procesów eutrofizacji. W ciągu jednego dnia statystyczny wędkarz odławia 0,54 kg ryb, a łączna masa pozyskanej ichtiofauny ze zbiorników w trakcie 365 dni połowów wynosi 10 052,1 kg ryb. Wykazano wzrost masy poławianych ryb wraz ze wzrostem ilości zanęty wrzucanej do wody. Analiza bilansu biogenów wykazała niestety niekorzystne oddziaływanie stosowania zanęt przez wędkarzy na jakość środowiska wodnego, mierzoną wzrostem ładunku fosforu i azotu.The article presents the basic parameters determining the fishing pressure on 5 lakes located in the basin of the Myśla in Myślibórz Lakeland. The carp species: roach (31.2%), bream (23.5%) and tench (8.3%), with a small number of predatory fish (pike 12.8%, perch 7.6%, pike-perch 3.6% and european eel 2.1%). The total share of carp fish is 72.0%, which means that the lakes may be in a state of fairly advanced eutrophication processes. Within one day, the angler fish catches 0.54 kg of fish and the total weight of the fish taken from the tank during 365 days of fishing is 10 052.1 kg of fish. The weight of the fish caught was increased with the increase in the amount of groundbait thrown into the water. Unfortunately, the analysis of biogen balance showed the unfavorable impact of the use of groundbaits by anglers on the quality of aquatic environment measured by the increase of phosphorus and nitrogen

Age, growth rate, and condition of vendace, Coregonus albula (L.), from some Pomeranian Lakes (NW Poland)

Background. Vendace, Coregonus albula (L.), is one of the most valuable components of Polish lake ichthyofauna. The vendace from different lakes differ in their principal vital characteristics (such as growth rate etc.) and it is therefore crucial to determine those characteristics from different throphic types of lakes in order to implement proper measures of fisheries management for those coregonids. The aim of the present paper was therefore to learn principal biological features of vendace populations representing three different Pomeranian lakes. Materials and methods. Comparative biological studies were carried out on 136 vendace from PeĹ‚cz Wielki Lake, 304 from BytyĹ„ Wielki Lake, and 62 from WeĹ‚tyĹ„ Lake (Pomerania Lakeland) collected within 2002-2003. The age and growth rate of the fish were determined from scales. Fulton′s condition factor and the total length-weight relation were used to determine fish condition. Results. Gillnet selectivity influenced fish age structure and size. For example, among 502 vendace obtained, in total, from the three lakes, 75.7% (380 specimens) were 2+. The results of back-calculations and the parameters of von Bertalanffy′s growth equation revealed distinct disproportions in the total length in individual age groups (PeĹ‚cz Wielki Lake: Lt = 213.22[1 - e-0.49576(1 + 1.055013)]; BytyĹ„ Wielki Lake: Lt = 219.17[1 - e-0.733553(1 + 0.040147)]; WeĹ‚tyĹ„ Lake: Lt = 255.08[1 - e-0.571108(1 + 0.023036)]) Slower length- and weight growth rates were observed in the fish from PeĹ‚cz Wielki Lake. Conclusion. The growth rates, determined using back-calculations, were different for the vendace populations representing lakes PeĹ‚cz Wielki, BytyĹ„ Wielki, and WeĹ‚tyĹ„ in the sequential years of fish lives. The fish from WeĹ‚tyĹ„ Lake were characterized by average growth, whilst the fish from the remaining reservoirs were characterized by slow or very slow growth. The lower condition values and growth rates from PeĹ‚cz Wielki Lake were probably the result of poor environmental conditions in this body of water

Biological and morphological characteristics of vendace, Coregonus albula L. from lakes Drawsko and Pełcz

Comparative biological and morphometric studies were carried out on vendace from lakes Drawsko and PeĹ‚cz in two seasons of the year. The summer sample covered 106 specimens of this fish from Drawsko Lake and 120 specimens from Pełcz Lake, while the autumn sample consisted of 110 and 104 specimens, respectively. This survey demonstrated a number of significant differences in the individual weights, the condition of the fish, as well as in the mensural and meristic characters. Out of a total of 28 analysed linear parameters, such differences were recorded in 15 characters in summer and in as many as 19-in autumn. Also 3 out of 11 meristic parameters showed differences. Vendace of Pełcz Lake, among other things, had larger (related to fork length, FL) linear dimensions of individual body parts and they had smaller maximal body depth. The reasons behind the above-mentioned differences may be different environmental conditions of both lakes

Invasion dynamics of round goby Neogobius melanostomus (Pallas 1814) in the Oder estuary

Naturalnym miejscem występowania babki byczej (Neogobius melanostomus) jest rejon Pontokaspijski: zlewiska morza Azowskiego, Czarnego i Kaspijskiego [1], wykazując w ostatnich dekadach gwałtowną ekspansję w Europie [2]. W estuarium Odry po raz pierwszy babki bycze złowione były na początku XXI wieku w Zatoce Pomorskiej [3]. W polskiej części Zalewu Szczecińskiego w 2009 roku, [4], potwierdzili obecność tych ryb. Natomiast w latach 2013-2014 babki bycze licznie notowano w tych akwenach, a nawet w Odrze na wysokości Szwedt i Widuchowej [5]. Biorąc powyższe pod uwagę, jak również negatywny wpływ babki byczej na środowisko wodne, zasadne jest podjęcie badań monitoringowych dotyczących ważniejszych cech biologicznych i populacyjnych.Natural place of occurrence round goby (Neogobius melanostomus) is Caspian area: catchment Sea of Azov, Black Sea and Caspian Sea [1], where in the last decades was a rapid expansion in Europe [2]. In the estuary of the Oder River in the Pomeranian Bay for the first time round goby was caught in the early twenty-first century [3]. In the Polish part of the Szczecin Lagoon in 2009 [4] confirmed the presence of these fish. Whereas in 2013-2014 round goby was many times recorded in these areas, and even in the Odra River at the height of Szwedt and Widuchowa [5]. Considering the above, as well as the negative impact round goby on the aquatic environment, it is reasonable to undertake monitoring study about important biological characteristics and population

Possibilities of recreational fishing use of small mid-field water reservoirs on the background of environmental conditions

W artykule przedstawiono podstawowe parametry określające presję połowową na 8 niewielkich zbiornikach wodnych na terenach rolniczych w województwie zachodniopomorskim. Oceniono warunki siedliskowe ryb i zróżnicowanie chemiczne wód w poszczególnych zbiornikach. Przedstawiono ichtiofaunę złowioną przez wędkarzy w każdym akwenie, określono współczynnik stałości występowania (Ci) i dominacji (Di) gatunków. Badania hydrochemiczne nie wykazały podwyższonego poziomu biogenów w badanych zbiornikach wodnych w porównaniu z akwenami o większej powierzchni. Łącznie ze wszystkich 8 zbiorników w dwuletnim cyklu badawczym odłowiono 501 ryb należących do 9 gatunków. Wśród złowionych ryb zanotowano największą liczbę karasi pospolitych (Carassius carassius L.), których łącznie w okresie dwóch lat badań złowiono 127 szt. Nieco mniej odłowiono okoni (Perca fluviatilis L.) i płoci (Rutilus rutilus L.) – w obu przypadkach po 92 osobniki. Największą wartość współczynnika dominacji odnotowano w odniesieniu do karasia pospolitego (25,25%), a najmniejszy – jazia (Leuciscus idus L.) (0,20%). Również największe wartości współczynnika stałości występowania (Ci) stwierdzono w przypadku karasia pospolitego (87,5%) i nieznacznie niższy – lina (Tinca tinca L.) (75,0%). W dwuletnim cyklu prowadzonych badań rozdano 99 ankiet wędkarskich, a zbiornikiem wodnym, na którym poławiało najwięcej wędkarzy, był ZW1 (35 wędkarzy).The article presents the basic parameters determining the fishing pressure on 8 ponds located on agricultural areas in West Pomeranian Region. The habitat conditions of fishes were assessed and the hydrochemical differentiation of individual ponds was given. The ichthyofauna caught by anglers in each ponds was presented, coefficient of occurrence (Ci) and dominance of ichthyofauna (Di) were determined. Hydrochemical studies did not show elevated nutrient levels in each reservoir water. In total, from all 8 ponds in a two-year study cycle, 501 fish belonging to 9 species were caught. Among the fish caught by anglers, the largest number of crucian carp (Carassius carassius L.) was recorded, a total of 127 fish of this species were caught in two years of research. Then the most frequently caught fish were perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) – in both cases 92 individuals. The highest dominance coefficient was recorded in crucian carp (25.25%), and the lowest was recorded in ide (0.20%). Also, the highest values of coefficients of constancy were found in crucian carp (87.5%), and tench (75.0%). In a two-year cycle of research, 99 angling questionnaires were distributed, and ZW1 (35 anglers) was the largest water reservoir with the largest number of anglers