Scholarly article on topic 'Effects of eutrophication on vendace, Coregonus albula (L.). II. Biological characteristics of vendace from selected lakes in Wielkopolska'

Effects of eutrophication on vendace, Coregonus albula (L.). II. Biological characteristics of vendace from selected lakes in Wielkopolska Academic research paper on "Agriculture, forestry, and fisheries"

0
0
Share paper
Academic journal
Archives of Polish Fisheries
OECD Field of science
Keywords
{""}

Academic research paper on topic "Effects of eutrophication on vendace, Coregonus albula (L.). II. Biological characteristics of vendace from selected lakes in Wielkopolska"

Arch. Pol. Fish. (2012) 20: 97-108 DOI 10.2478/v10086-012-0012-4

RESEARCH ARTICLE

Effects of eutrophication on vendace, Coregonus albula (L.). II. Biological characteristics of vendace from selected lakes in Wielkopolska

Malgorzata Fiszer , Antoni Przybyl, Wojciech Andrzejewski, Jan Mazurkiewicz, Janusz

Golski, Katarzyna Przybylska, Slawomir Runowski

Received - 05 December 2011/Accepted - 08 March 2012. Published online: 30 June 2012; ©Inland Fisheries Institute in Olsztyn, Poland Citation: Fiszer M., Przybyl A., Andrzejewski W., Mazurkiewicz J., Golski J., Przybylska K., Runowski S. 2012 - Effects of eutrophication on vendace, Coregonus albula (L.). II. Biological characteristics of vendace from selected lakes in Wielkopolska - Arch. Pol. Fish. 20: 97-108.

Abstract. The aim of the study was to evaluate the dynamics of changes in body weight, length, and condition, as well as to determine and compare the age structure, length increments, and fecundity of vendace from four lakes in the Wielkopolska region. The smallest mean total length (21.1 cm) and body weight (82.59 g) were recorded for specimens from Lake Lubikowskie, while the greatest values were noted for those from Lake Strzeszynskie at 23.07 cm and 118.01 g, respectively. The smallest mean value for Fulton's condition factor was noted in the vendace from Lake Lubikowskie (0.86), while the highest was noted for specimens caught in Lake Strzeszynskie (0.93). Slightly less than 50% of the vendace caught in Lake Lubikowskie were 1-year-old-fish, whereas 2-year-old fish predominated in the other lakes. In the vendace samples from Lakes Gorzynskie and Strzeszynskie no 1-year-old specimens were noted, while 3-year-old fish accounted for 35.3% and 23.3%, respectively, of the total fish caught. The total length increments of vendace in the analyzed lakes were similar, and according to the classification by Szczerbowski, did not vary from the Polish mean. The highest absolute fecundity was observed in fish from Lake Gorzynskie, but it was considerably lower (almost two-fold) in the vendace caught in Lake Strzeszynskie.

Keywords: age, condition, fecundity, growth, vendace

M. Fiszer, A. Przybyl, W. Andrzejewski [H], J. Mazurkiewicz,

J. Golski, K. Przybylska, S. Runowski

Department of Fisheries and Aquaculture, Institute of Zoology

Poznan University of Life Sciences

Wojska Polskiego 71c, 60-125 Poznan, Poland

Tel./fax: +48 618487706; e-mail: wojtek@up.poznan.pl

Introduction

Papers published to date concerning the comprehensive biology of vendace, Coregonus albula (L.), have clarified many issues connected with environmental requirements of this species (Walczak 1953, Bernatowicz 1958, Radziej 1973), catch rates and fishing methods (Turunen et al. 1998), the effects of biotic (Winfield et al. 1996a, Huusko and Sutela 1992, 1997, Huusko et al. 1996) and abiotic factors (D^browski and Eichler 1972) on fluctuations in productivity, and finally the production of stocking material (Mamcarz 1994). The following issues are also frequently discussed with regard to vendace: the analysis of age, length increments, and body weight (Szypula 1970, Viljanen 1988a, Huuskonen 1997); fecundity and reproduction (Vijanen 1988b, Demska-Zak^s and Dlugosz 1995, Czerniejewski and Filipiak 2002a); nutrition of adult fish (B0hn and Amundsen 2001, Czerniejewski and Rybczyk 2002, D^browski et al. 2002); nutrition of juvenile vendace (Karjalainen et al. 1997, Huusko and Sutela 1998).

In view of the deteriorating water quality in Polish lakes and their progressing eutrophication, it is of particular importance to continue these studies because of the high variability in individual bio-morphometric parameters of vendace inhabiting

different types of lakes. The scope of the investigations presented in this paper include an evaluation of the dynamics of changes in individual weights and total lengths, the condition of vendace in lakes of the Wielkopolska region, and determining and comparing the age structure, length increments, and fecundity of vendace caught in the analyzed lakes.

Study area

Analyses were conducted in four lakes in the Wielkopolska Region - lakes Dominickie, Gorzynskie, Lubikowskie, and Strzeszynskie. The parameters differentiating the lakes most strongly were area, depth, area-depth index, shoreline development, and fish yield index (Fiszer et al. 2012). In terms of morphometry, lakes Gorzynskie and Lubikowskie are most suitable for optimal vendace fishery management. The least developed stratification was observed in Lake Dominickie, while the most marked stratification was noted Lake Gorzynskie, which has the smallest epilimnion depth, the highest thermocline temperature gradient, and a deep, cool hypolimnion. Considerable deoxygenation was observed in the hypolimnion in the summer season in all the lakes; however, in Lake Strzeszynskie oxygen deficits were also noted in the metalimnion. According to the analysis of physicochemical indexes and trophic state indexes, all of the analyzed lakes were of good water quality. The trophic states of lakes Gorzynskie and Lubikowskie were designated as bordering on the mesotrophic and eutrophic states, while lakes Dominickie and Strzeszynskie were designated as eutrophic.

Materials and methods

Specimens of vendace were collected in 2005 in the spring (9-16 May), summer (12-28 August), and autumn (20-26 November). These fish were caught during commercial night catches performed using gillnets with mesh sizes of 18,20,22, and 24 mm. The vendace

were selected at random from the whole catch on a given day, transported on ice to the laboratory, and packed in batches of ten specimens each in double plastic bags that prevented tissue water expression, and deep-frozen at a temperature of -28°C. A total of 1400 fish were analyzed with 350 specimens from each lake. Spring and summer samples comprised 100 specimens, while fall samples consisted of 150 specimens (Ciepielewski 2000a, 2000b). All of the specimens caught in the fall were subjected to biological analyses that included determining fish condition, age, growth rate, and absolute and relative fecundity in females. The first parameter was also calculated for fish caught in the spring and summer seasons using Fulton's condition factor (Opuszynski 1983). Fish age was determined using collected scale material as presented by Heese (1992). Readings were performed using the illustrations in studies by Bernatowicz (1952) and Ciepielewski (1971). Growth rates for total fish length were determined using reverse readings according to Dahl-Lea (Szypula etal. 2001). Absolute, individual fecundity and relative fecundity per 100 g of body weight was determined by gravimetry using female gonad analysis in the period preceding spawning.

Results

Fish length, body weight, and condition

The total length (TL) of all caught vendace ranged from 14.3 to 31.2 cm (Table 1). The smallest mean length (21.1 cm) was noted in vendace from Lake Lubikowskie, while the greatest (23.07 cm) was recorded for fish from Lake Strzeszynskie. The greatest length range was noted in vendace from Lake Gorzynskie. The mean body weight of vendace caught from all the analyzed lakes was 99.9 g at a range of 38.6 to 342.1 g (Table 1). Specimens caught in Lake Lubikowskie were characterized by the lowest mean weight (82.59 g), whereas the greatest (118.01 g) was recorded for vendace from Lake Strzeszynskie. The fishes caught in Lake Gorzynskie had the greatest body weight range from 64.1 to 342.1 g.

Table 1

Mean total length (TL), body weight (BW), and Fulton condition factor (CF) of vendace from the studied lakes by season. Sample size for each lake is 100 for spring and summer and 150 for autumn

Season TL (cm) Range (cm) SD BW(g) Range (g) SD CF Range SD

Lake Dominickie

Spring 20.47 18.0-23.1 10.91 89.44 56.4-142.6 14.49 1.04 0.84-1.37 0.10

Summer 22.14 20.1-24.8 11.36 90.34 64.4-121.2 13.74 0.83 0.70-0.98 0.05

Autumn 22.19 19.9-24.5 8.68 94.90 66.5-130.9 13.18 0.87 0.62-1.08 0.09

Mean 21.60 18.0-24.8 10.31 91.56 56.4-142.6 13.80 0.90 0.62-1.37 0.12

Lake Gorzynskie

Spring 21.96 14.3-26.4 20.11 104.19 64.1-158.5 22.70 0.96 0.81-1.43 0.09

Summer 22.05 19.7-25.6 11.29 97.79 67.1-153.0 17.23 0.91 0.55-1.09 0.07

Autumn 23.75 20.0-30.7 17.03 120.33 67.0-342.1 36.58 0.88 0.64-1.21 0.11

Mean 22.58 14.3-30.7 16.14 107.43 64.1-342.1 25.50 0.91 0.50-1.43 0.09

Lake Lubikowskie

Spring 21.58 19.5-31.2 15.45 77.92 53.3-140.8 15.73 0.77 0.67-0.93 0.06

Summer 19.90 17.2-25.5 19.05 72.22 45.1-159.0 22.87 0.89 0.71-1.08 0.08

Autumn 21.96 17.3-27.9 26.15 97.65 38.6-219.6 36.97 0.88 0.63-1.19 0.09

Mean 21.14 17.2-31.2 20.21 82.59 38.6-219.6 25.19 0.86 0.63-1.19 0.09

Lake Strzeszynskie

Spring 21.81 17.3-29.0 21.05 111.91 51.0-222.2 32.29 1.05 0.81-1.42 0.11

Summer 24.00 19.5-28.3 18.45 135.65 75.9-243.5 37.54 0.96 0.76-1.43 0.14

Autumn 23.38 19.7-29.4 18.70 106.47 66.7-277.0 31.09 0.82 0.63-1.15 0.09

Mean 23.07 17.3-29.4 19.40 118.01 51.0-277.0 33.64 0.93 0.63-1.43 0.15

The lowest mean value of Fulton's condition factor was observed among vendace from Lake Lubikowskie (0.86), whereas the highest was noted in specimens caught in Lake Strzeszynskie (0.93) (Table 1). This factor fluctuated within the broadest range in vendace from Lake Gorzynskie (0.55-1.43), while the narrowest range was noted in the fish from Lake Lubikowskie (0.63-1.19).

Age structure and body length increments

Slightly less than 50% of the vendace caught in Lake Lubikowskie consisted of 1-year-old fish, while 2-year old specimens predominated in the other lakes (Table 2). No 1-year-old specimens were noted in the vendace samples caught in lakes Gorzynskie and Strzeszynskie, while 3-year-old fish accounted

for 35.3% and 23.3%, respectively, of all the fish caught. Moreover, six fish from Lake Gorzynskie were identified as 4 + , which accounts for 4% of the sample caught in that lake.

Vendace caught in Lake Dominickie had the greatest growth rates in terms of length in the first year of life (on average 14.69 cm). In the second year this increment was over three-fold lower, while in the third year it was 18-fold lower (Table 2). Vendace from Lake Gorzynskie were characterized by the greatest increases in body length increments in the first two years of life. In the third and fourth years this increment was, on average, three times lower in comparison to that of the first year. The character of length increment increases in vendace from Lake Lubikowskie was typical and similar to that in ven-dace from the lakes described above, i.e. very high growth was noted in the first year of life, increment

Table 2

Growth rate of vendace from the studied lakes calculated with the Dahl-Lea method (by age groups)

Age group n Li L2 L3 L4

Lake Dominickie

I 35 16.06

II 109 14.34 18.65

III 6 13.01 16.70 19.36

Mean 14.69 18.56 19.36

Total length growth 14.69 3.86 0.81

Lake Gorzynskie

II 91 10.69 17.37

III 53 9.41 14.63 19.84

IV 6 10.62 17.09 21.67 25.41

Mean 10.24 16.39 20.03 24.51

Total length growth 10.24 6.15 3.63 4.47

Lake Lubikowskie

I 70 15.6

II 48 13.53 18.83

III 32 13.36 18.17 21.81

Mean 14.49 18.57 21.81

Total length growth 14.49 4.08 3.24

Lake Strzeszynskie

II 115 13.74 18.75

III 35 10.98 16.32 21.31

Mean 13.09 18.18 21.31

Total length growth 13.09 5.08 3.12

increase was over three-fold lower in the second year, and it was the lowest in the third year of life (3.24 cm). The fastest growth rate in fish from Lake Strzeszynskie was recorded in the first year of life (13.09 cm), while in the second and third years a marked decrease in length increment growth was observed (Table 2).

The growth of vendace in the first year of life in lakes Dominickie, Lubikowskie, and Strzeszynskie was almost uniform and slight differences were recorded in their total lengths (range of 13.09-14.69 cm) (Table 2). In Lake Gorzynskie the growth rate of vendace was markedly slower and the value of it was much lower at 10.24 cm. In the second year of life the above mentioned trend was maintained; in Lake Gorzynskie the highest value of body length was

recorded in vendace. In the third year of life the described regularity was reversed; vendace grew fastest in Lake Gorzynskie (3.63 cm), while the growth rate was slowest in fish from Lake Dominickie (0.81 cm). The significant growth variability of vendace from Lake Gorzynskie is probably due to environmental conditions and food availability.

Fecundity

The highest absolute fecundity was noted in fish from Lake Gorzynskie, while nearly two-fold lower fecundity was recorded in vendace caught in Lake Strzeszynskie (Table 3). In lakes Lubikowskie and Strzeszynskie the highest absolute fecundity was observed for vendace aged 3 + , while in Lake

Table 3

Mean and range values of individual absolute fecundity of vendace from the studied lakes by age group

Age groups

Total 1 + 2 + 3 + 4+

Lake Dominickie

n 90 32 53 5

Mean 10363 10109 10467 9727

Range 5321-16278 5321-14008 6025-16278 8102-12131

SD 2194 2192 2235 1707

Lake Gorzynskie n 78 48 27 3

Mean 15757 14397 15570 39221

Range 8368-54589 8368-22796 9040-26587 20300-54589

SD 6485 3238 3908 17419

Lake Lubikowskie

n 132 62 42 27 1*

Mean 10294 8126 11684 13191

Range 2622-21992 2624-14911 4686-21193 9449-21992

SD 3827 2256 4246 3161

Lake Strzeszynskie n 34 23 10 1*

Mean 9581 7404 14547

Range 3670-46041 3670-26150 1297-46041

SD 8542 5790 12617

*fish not considered in the analysis

Table 4

Mean and range values of individual relative fecundity of vendace from the studied lakes by age group

Age groups

Total 1 + 2+ 3 + 4+

Lake Dominickie

n 90 32 53 5

Mean 10322 10628 10271 9817

Range 5892-13795 5892-13780 6031-13795 9121-10679

SD 1727 1771 1762 643

Lake Gorzynskie n 78 48 27 3

Mean 11350 11243 11373 12867

Range 7285-17492 7362-17492 7285-14575 9244-15957

SD 2145 2115 2090 3388

Lake Lubikowskie

n 132 62 42 27 1*

Mean 10416 10951 10098 9664

Range 4380-16619 4380-16167 6809-16619 6546-12746

SD 2117 2430 1831 1713

Lake Strzeszynskie n 34 23 10 1*

Mean 6418 5687 7896

Range 2380-16621 2380-12694 1239-16621

SD 3318 2925 4103

*fish not considered in analysis

Gorzynskie it was noted in age group 4 + . In the latter case, the sample was not representative since it comprised only three specimens.

The relative fecundity of vendace from the analyzed lakes located in the Wielkopolska region fell within a broad range from 6418 in Lake Strzeszynskie to 11350 in Lake Gorzynskie (Table 4). It must be emphasized that, similarly to absolute fecundity, slight differences of a maximum of 0.9% were observed in the relative fecundity of vendace caught in lakes Dominickie and Lubikowskie. The mean value of this parameter in the above mentioned lakes was 10322 and 10416 eggs per 100 g 1 body weight.

Discussion

Commercial catches of vendace in Poland are performed mainly using gillnets with a mesh size of 24 mm. This permits catching fish with body lengths ranging from 17.8 to 24.2 cm, while the length of fish caught with maximum efficiency was 21.0 cm (Ciepielewski 1974a). Vendace used for the realization of the objectives of this study were caught using gillnets with a varied mesh size (18-24 mm), which resulted in high heterogeneity in total length and individual weight of fish samples caught from lakes included in these investigations. However, the use of multi-mesh gillnets with varied mesh size increased the qualitative representativeness of the fish samples.

Vendace condition in this study was evaluated using Fulton's factor, which is used widely in such studies (Ritterbusch-Nauwerch 1995). The mean value of this parameter indicates the markedly better condition of vendace in Lake Strzeszynskie in comparison to those from the other lakes, although in terms of morphometric and physicochemical parameters this lake cannot be classified as an advantageous habitat for vendace. In turn, fish from Lake Lubikowskie, which is characterized by the best environmental conditions for this species, exhibited the lowest condition factor. The reasons for this and the different maximum individual lengths and weights

probably lie in differences of the availability of adequate nutrition bases for vendace. This factor could have been of greater importance than environmental factors.

A comparison of the estimated condition factors with literature data is hindered because some authors use total length (Szypula 1970, Sarvala et al. 1992), body length (Bernatowicz 1958), or caudal length (Winfield et al. 1996b, Czerniejewski and Filipiak 2002a, 2002b, Czerniejewski et al. 2002) to determine this parameter (Table 5). When using empirical data presented in the three most recent publications, the values of Fulton's condition factor were determined based on fish total length. Data concerning the condition of fish from 11 lakes in western Pomerania in view of the 4 analyzed lakes from the Wielkopolska region indicate that, except for Lake Lubikowskie, vendace from the other three lakes are characterized by good condition. Differences in the values of Fulton's factor could have been the result of different catch seasons, and also because the effect of fish length and age was not considered in these analyses.

A significant element of a rational fishery management is to identify the age structure of fish as well as their growth rate. Vendace is classified as a pelagic fish species with a relative short life cycle, while in commercial catches as much as 80-90% are comprised by fish aged 1+ to 3+ (Viljanen 1986, Auvinen 1987, Christianus 1995). However, in accordance with the suggestions presented by Leopold (1972), because of their short life cycle, vendace catches should target specimens aged 2+ with maximum intensity. In accordance with the above mentioned recommendations, commercial catches of this species should be performed using gillnets with mesh size of 24 mm.

The age structure of the population was similar in vendace samples from the lakes included in this study. The adequately high proportion of vendace specimens aged 1+ and 2+ years in catches from the analyzed lakes was because the growth rate of this species is greatest in the first three years of life (Bernatowicz et al. 1975). However, as a result of changes in fish growth, the performance of catches

Table 5

Values of Fulton condition factors of vendace in selected lakes of Poland

Fulton condition factors

Lake Authors Season Mean Range

Pomerania Region

Siecino Czerniejewski et al. (2002a) Autumn 0.86 0.65-0.99

Komorze Czerniejewski and Filipiak (2002a) Autumn 0.88 0.7-1.0

Pile 0.84 0.58-0.96

Lesne 0.87 0.67-1.01

Morynskie 0.91 0.68-1.21

Drawsko Czerniejewski and Filipiak (2002b) Summer 0.79 0.66-0.92

Autumn 0.86 0.7-1.1

Pelcz Summer 0.74 0.55-0.88

Autumn 0.81 0.50-1.06

Wielkopolska Region

Dominickie Own data 0.90 0.62-1.37

Gorzynskie 0.91 0.50-1.43

Lubikowskie 0.86 0.63-1.19

Strzeszynskie Mean of all seasons 0.93 0.63-1.43

using identical gear, or the decision to cease fishing exploitation in a lake, aging can occur in the exploited segment of the population (Ciepielewski 1974b, Winfield et al. 1996b).

Vendace is characterized by high growth rate variation in different lakes. The comparison of the data presented in Table 6 regarding the total length of fish in each year of life indicates that vendace inhabiting the northernmost lakes were characterized by the slowest growth rates. This was confirmed indirectly by an analysis of growth rates of different populations of vendace from lakes in Finland (Viljanen 1988a). Viljanen suggests that with increasing latitude, the body length obtained by vendace in subsequent years of life is significantly reduced, probably due to the lower productivity of these lakes. Bauch (1961) suggested that specific environmental conditions play a decisive role in vendace growth, and the greatest increments as well as the maximum age are typically found in lakes with an abundance of crustaceous plankton. This is confirmed by the results of studies conducted by Radziej (1973).

Apart from the abundance of zooplankton in lakes, growth rates of these fish are also influenced by lake size (Marciak 1970), lake depth, water transparency and oxygenation during summer stagnation (Bernatowicz et al. 1975), and population size (Valkeajaervi and Bagge 1993). In Poland, the highest growth rate is noted among populations inhabiting lakes in the Wielkopolska Lake District and the Pomerania region, which indicates that conditions there are considerably better for the growth of this species than they are in the lakes of the Mazurian Lake District (Bernatowicz 1953, Czeczuga 1959, Marszalek 1961, Marciak 1970, Bernatowicz et al. 1975, Mastynski 1978, Christianus 1995, Czerniejewski et al. 2002) (Table 7).

Criteria presented by Szczerbowski (1978) were applied to perform an accurate evaluation of the growth of the analyzed fish. According to this author, specimens that reached a length of approximately 20 cm (19.8-21.5 cm) in the third year of life are considered to be of average growth. Such growth dynamics were noted found for vendace from all of the the four analyzed lakes.

Table 6

Growth rates of vendace in different European countries

Total length of vendace (mm)

Country Authors 1 2 3 4 5 6

Scandinavia (14 lakes) Bauch (1961) 95 145 170 193 248 267

Norway (5 lakes) Amundsen et al. (1999) Sandlund (1992) 114 153 173 192 209

Finland Viljanen (1988a) 103 136 158 171 178

Soviet Union (3 lakes) Nikolski (1970) 111 168 206 225

Germany (45 lakes) Bauch (1961) 111 175 202 219 236 273

Poland (186 lakes) Marciak (1970) 120 174 202 223 249 267

Table 7

Growth rates of vendace in different regions of Poland

Total length of vendace (mm)

Region Lake Author 1 2 3 4 5 6

Mazury Dejguny Bernatowicz (1953) 144 206 247

Krzywe 114 172 236 260 273

Dobskie 145 204 232 249 265

Mamry Pln. 145 197 229 253 275

Harsz 127 194 225 249 252

Kisajno 138 197 224 235

Goldopiwo 91 145 205 233 250 273

Buwelno 87 138 189 209 233 265

Rydzowka 78 136 187 208 237 270

Jagodne 95 139 186 209 230 255

Talty 95 141 184 207 213

Lasmiady 112 160 183 204

Tajty 85 145 176 196 213 238

Ublik 108 143 162 173 186

Rajgrodzkie Czeczuga (1959) 99 158 192 220

Maroz Christianus (1995) 95 137 158 192

Lutry 107 146 156

Narie 95 145 166 171

Is^g 114 167 191 214

Pomorze Wdzydze Marszalek (1961) 80 145 196 231 261 284

Pl^sno Marciak (1970) 132 197 230

Ciesz^cin 99 181 229 259 274

L^towo 158 205 225

Zerdno 149 213 247 267

Insko 137 205 235 263

Wielkopolska Janikowo Lawica Marciak (1970) 181 162 232 210 230

Sremskie 145 209 256 277 290

Trzesniowskie 95 167 201

Gorzynskie Mastynski (1978) 112 179 232

Dominickie Own data 146 185 193

Gorzynskie 102 163 200 245

Lubikowskie 144 185 218

Strzeszynskie 131 181 213

Table 8

Mean values of individual relative fecundity of vendace from Europe by age group

Age groups

Country Study site Authors 1 + 2 + 3 + 4 + 5 + 6+ 7 + 8+

Finland Bay of Bothnia Lehtonen (1981) 1.63 3.25 4.45 4.48 5.35 6.26

Lake Pyhajarvi Sarvala et al. (1992) 9.88 13.51 17.36 18.90

Soviet Union Juribej River Vysegorodcev (1977) 12.65 9.73 12.43 15.37 21.72 26.88

Lake Ladoga Diatlov (1978) 0.85 2.00 3.16 3.51 5.21 5.57 7.95 7.79

Lake Onega Berg (1948) 1.30 2.00 2.90 3.80

Germany Lake Stechlin Anwand (1998) 3.58 5.36 7.13

Poland (Mazury) Lake Isqg Demska-Zak^s and Dlugosz (1995) 13.46 19.83 31.07

Lake Narie 4.44 8.77

Lake Maroz Ciepielewski (1974c) 5.67 7.81 10.62 13.19 15.73 18.69 18.98

Lake Mamry Bernatowicz (1953) 4.10 4.60 8.50

Lake Dargin 6.70 8.30 8.80

Lake Kisajno 8.30 10.70 14.10

Lake Dobskie 5.60 7.00

Poland (Pomerania) Lake Komorze Czerniejewski and Filipiak (2002a) 8.52 11.81

Lake Drawsko 8.05 14.88 21.02

Lake Pile 6.38 7.33 8.28

Lake Lesne 4.65 5.68 7.95

Lake Morynskie 5.82 6.02 5.73

Lake Pelcz 2.73 2.94 3.62

Lake Siecino Czerniejewski et al.(2002) 6.03 6.74

Poland (Wielkopolska) Lake Lubikowskie Mastynski (1978) 4.30 13.65 19.98

Lake Bechno 7.40 11.27 14.53 16.71

Lake Lubrza 4.45 8.21 12.15

Lake Chlop 5.28 8.50

Lake Sremskie Budych and Iwaszkiewicz (1964) 18.20 20.40 62.60

Lake Strzyzmin 9.30 10.00 15.20

Lake Chalinskie 7.10 12.30 14.80

Lake Tuczno Czerniejewski et al.(2002a) 5.07 9.80 11.46

Lake Dominickie Own data 10.10 10.46 9.27

Lake Gorzynskie 14.39 15.57 39.22

Lake Lubikowskie 8.12 11.68 13.19

Lake Strzeszynskie 7.40 14.54

Vendace is a fish species of relatively low fecundity; however, this is compensated by its early sexual maturity. Depending on environmental factors in lakes, males of this species are capable of reproducing most frequently as soon as the second year of life, while females can do so in the third year of life (Bernatowicz et al. 1975). Many authors have reported that in certain cold lakes in northeastern

Europe the gonads ofvendace mature as late as in the third year of life (Aass 1972, Koskova 1977), and in case of vendace from Siberia they do so at the age of 4+ (Vysegorodcev 1977). Because of the thermal characteristics in Polish lakes, vendace is capable of reproducing as early as at the age of 1+ (Budych and Iwaszkiewicz 1964, Ciepielewski 1974c, Demska-Zak^s and Dlugosz 1995). This has been

confirmed by the results of studies conducted by the authors of this paper on lakes from the Wielkopolska region (Table 8). However, in spawning grounds, three-year-old fish predominate, and their fecundity is much greater than that of vendace aged 1+ (Bernatowicz et al. 1975, Dlugosz and Worniallo 1985).

Vendace fecundity, as well as that of other fish species, fluctuates depending on environmental and population factors (Zawisza and Backiel 1970a, Viljanen 1988b, Gregersen et al. 2011). This is why the range of this parameter in different lakes is very broad. In their investigation of vendace from Mazurian lakes such as Is^g and Narie, Demska-Zak^s and Dlugosz (1995) reported that fish exhibiting a higher growth rate are also characterized by higher fecundity. This thesis could not be confirmed in the current study. Growth rates of fish in the four analyzed lakes in the Wielkopolska region were similar but fecundity was varied. The decidedly highest absolute and relative fecundity was noted in vendace from Lake Gorzynskie.

Conclusions

1. Despite adverse environmental conditions in ven-dace lakes with elevated trophic status, vendace can achieve greater dimensions and better condition. This is confirmed by comparing individual size and condition in the populations from lakes Strzeszynskie and Lubikowskie.

2. The predominance of fish aged 1+ in Lake Strzeszynskie and those aged 2+ in the other lakes is consistent with adopted standards.

3. The growth rate of vendace in the analyzed lakes is similar, and according to the classification presented by Szczerbowski, does not deviate from the mean in Poland.

4. The highest vendace fecundity was recorded in Lake Gorzynskie, while the lowest was noted in Lake Strzeszynskie.

Acknowledgments. This study was conducted within a project supported by Poznan University of Life Sciences.

Author contributions. M.F., A.P., W.A., and J.M. designed and performed the study; M.F., W.A., J.M., and J.G. analyzed the data; M.F., J.M., J.G., K.P., and S.R.

prepared the paper.

References

Aass P. 1972 - Age determination and year-class fluctuations of cisco, Coregonus albula L., in the Mjosa hydroelectric reservoir, Norway - Rep. Inst. Freshw. Research Drottiningholm 52: 5-22. Amundsen P.A., Staldvik F.J., Reshetnikov Y.S., Kashulin N., Lukin A., Bahn T., Sandlund O.T., Popova O.A. 1999 -Invasion of vendace Coregonus albula in a subarctic watercourse - Biol. Conser. 88: 405-413. Anwand K. 1998 - Comparisons of annual gonad cycle and fecundity between nominate and deepwater forms of vendace (Coregonus albula L.) in Lake Stechlin (State of Brandenburg, Germany) - J. Appl. Ichtyol. 14: 97-100. Auvinen H. 1987 - Fisheries in the Finnish zone of Lake

Pyhäjärvi (Karelia) - Finnish Fish. Res. 8: 53-57. Bauch G. 1961 - Die einheimischen Süsswaserfische -

NeumanVerlag Radebeul, Berlin, 198 p. Berg L.S. 1948 - Fish of Freshwaters of USSR and Neighboring Countries - Izdatel'stvo Akademii Nauk SSSR, Moskowva-Leningrad, 466 p. (in Russian).

Bernatowicz S. 1952 - Accuracy issues in determining age and growth using scales of vendace from different body parts - Rocz. Nauk Rol. 65: 311-335 (in Polish). Bernatowicz S. 1953 - The occurrence and growth of vendace in Mazurian lakes in relation to environmental conditions - Rocz. Nauk Rol. 67-B-1: 1-20 (in Polish). Bernatowicz S. 1958 - Observations on vendace development in small lakes - Pol. Arch. Hydrobiol. 4(17): 163-181 (in Polish).

Bernatowicz S., Dembinski W., Radziej J. 1975 - Vendace -

PWRiL, Warszawa, 284 p. (in Polish). Bahn T., Amundsen P.A. 2001 - The competitive edge of an

invading specialist - Ecology 82: 2150-2163. Budych J., Iwaszkiewicz M. 1964 - Vendace fecundity in lakes of the Sierakowski Lakeland - Rocz. WSR Poznan, 22: 13-20 (in Polish). Christianus J. 1995 - Age and growth of selected vendace (Coregonus albula L.) populations in Poland - Arch. Hydrobiol. Spec. Issues Advanc. Limnol. 46: 97-102.

Ciepielewski W. 1971 - Annual ring formation on the scales of vendace (Coregonus albula L.) - Rocz. Nauk Rol. 93-H-3: 25-34 (in Polish).

Ciepielewski W. 1974a - Growth, mortality and the relation of production to biomass ratio of Coregonus albula in the Lake Maroz - Rocz. Nauk Rol. 96-H-2: 7-22 (in Polish).

Ciepielewski W. 1974b - Selectivity of gill nets for the catches of Coregonus albula - Rocz. Nauk Rol. 96-H-1: 17-29 (in Polish).

Ciepielewski W. 1974c - The estimation of eggs quantities and of hatch survival rate of Coregonus albula in the Lake Maroz - Rocz. Nauk Rol. 96-H-2: 23-36 (in Polish).

Ciepielewski W. 2000a - Sample number of fish population age structure research - part I - Komun. Ryb. 1:13-21 (in Polish).

Ciepielewski W. 2000b - Sample number of fish population age structure research - part II - Komun. Ryb. 2: 15-21 (in Polish).

Czeczuga B. 1959 - The food and growth rate of vendace (Coregonus albula L.) in Rajgrodzkie Lake - Rocz. Nauk Rol. 74-B-3: 497-508 (in Polish).

Czerniejewski P., Filipiak J. 2002a - Fecundity assessment of vendace, Coregonus albula L. from six lakes in Polish Western Pomerania - Acta. Ichtyol. Piscat. 32: 71-82.

Czerniejewski P., Filipiak J. 2002b - Biological and morphological characteristics of vendace, Coregonus albula L., from lakes Drawsko and Pelcz - Acta. Ichthyol. Piscat. 32: 53-69.

Czerniejewski P., Rybczyk A. 2002 - Feeding of vendace (Coregonus albula L.) in fall period - Komun. Ryb. 5: 7-10 (in Polish).

Czerniejewski P., Filipiak J., Przybyl A. 2002 - Biological characteristics of vendace (Coregonus albula) from the Tuczno Wielkie and Siecino lakes - Sci. Pap. Agric. Univ. Pozn. Anim. Sci. 4: 77-90.

Dqbrowski B., Eichler M. 1972 - The effect of the course of temperatures on fluctuations of Coregonus albula Linnaeus production - Rocz. Nauk Rol. 94-H-2: 59-73 (in Polish).

Dqbrowski K., Czesny S., Matusiewicz M. 2002 - Coregonids - In: Nutrient requirements and feeding of finfish for aquaculture (Eds) C.D. Webster, C.E. Lim. Cabi Publishing, New York, 230-244.

Demska-Zakçs K., Dlugosz M. 1995 - Fecundity of vendace from two lakes of Mazurian lake district - Arch. Pol. Fish. 3: 37-50.

Diatlov M.A. 1978 - O populacionnoj nieiednorodnosti rjapuski Coregonus albula L. Ladozskowo ozera - Vopr. Ikhtiol. 18: 615-623 (in Russian).

Dlugosz M., Worniallo E. 1985 - Variability of vendace (Coregonus albula L.) gonads in the annual cycle, in three lakes of Mazurian lakeland - Acta. Ichthyol. Piscat. 15: 171-189.

Fiszer M., Przybyl A., Andrzejewski W., Mazurkiewicz J., Golski J., Przybylska K., Runowski S. 2012 - Effects of eutrophication on vendace Coregonus albula (L.). I. Lim-nological characteristic of selected lakes in Wielkopolska - Arch. Pol. Fish. 20: 85-95.

Gregersen F., Vallestad L.A., 0stbye K., Aass P., Hegge O. 2011 - Temperature and food-level effects on reproductive investment and egg mass in vendace, Coregonus albula - Fisheries Manag. Ecol. 18: 263-269.

Heese T. 1992 - Optimizing methods for determining fish growth rates using back-calculations - Wyd. WSI, Koszalin, 155 p. (in Polish).

Huusko A., Sutela T. 1992 - Fish predation on vendace (Coregonus albula L.) larvae in Lake Lentua, Northern Finland - Pol. Arch. Hydrobiol. 39: 381-391.

Huusko A., Sutela T. 1997 - Minnow predation on vendace larvae: intersection of alternative prey phenologies and size-based vulnerability - J. Fish Biol. 50: 965-977.

Huusko A., Sutela T. 1998 - Diel feeding periodicity in larvae of the vendace (Coregonus albula L.) and influence of food availability and environmental factors on food intake - Ecol. Freshw. Fish. 7: 69-77.

Huusko A., Vuorimies O., Sutela T. 1996 - Temperature- and light-mediated predation by perch on vendace larvae - J. Fish Biol. 49: 441-457.

Huuskonen H. 1997 - Age and energy allocation of coregonid larvae and juveniles: analysis of otolith microstructure and bioenergetics - PhD thesis, Univ. Joensuu, Publications in Sciences 45: 1-28.

Karjalainen J., Turunen T., Helminen H., Sarvala J., Huuskonen H. 1997 - Food selection and consumption of 0+ smelt (Osmerus eperlanus L.) and vendace (Coregonus albula L.) in pelagial zone of Finnish lakes -Arch. Hydrobiol. Spec. Issues Advanc. Limnol. 49: 37-49.

Koskova L.A. 1977 - Bielozerskaja rjapuska Coregonus sardinella vessicus Drjagin v saratovskom vodochra-nilisce - Vopr. Ikhtiol. 17: 545-548.

Lehtonen H. 1981 - Biology and stock assessments of coregonids by the Baltic coast of Finland - Finn. Fish. Res. 3: 31-83.

Leopold M. 1972 - Methodology of forecasting and evaluating catches of fishes with short lifetime in the polish lakes (on the example of Coregonus albula (Linnaeus)) - Rocz. Nauk Rol. 94-H-4: 1-98 (in Polish).

Mamcarz A. 1994 - An attempt of cage rearing of vendace (Coregonus albula L.) originated from populations with different growth rates - Acta Ichtyol. Piscat. 16:109-122.

Marciak Z. 1970 - Natural foundation of vendace management - In: Managing vendace lakes, part I. Wyd. IRS, Olsztyn, 39: 8-13 (in Polish).

Marszalek W. 1961 - Growth of vendace in Lake Wdzydze -Rocz. Nauk Rol. 93-D: 201-220 (in Polish).

Mastynski J. 1978 - Whitefish (Coregonus lavaretus L.) and vendace (Coregonus albula L.) in lakes of Western Poland - Rocz. AR Poznan 85: 1-26 (in Polish).

Nikolski G. 1970 - Essentials of ichthyology - PWRiL, Warszawa, (in Polish).

Opuszynski K. 1983 - Fundamentals of fish biology- PWRiL, Warszawa, 297-300 p. (in Polish).

Radziej J. 1973 - The effect of site upon slowly growing Coregonus albula (Linnaeus 1758) transferred from the Lake Narie to the Lake Wierzbiczany - Rocz. Nauk Rol. 95-H-1: 129-146 (in Polish).

Ritterbusch-Nauwerck B. 1995 - Condition or corpulence, fitness or fatness: a discussion of terms. - Arch. Hydrobiol. Spec. Issues Advanc. Limnol. 46: 109-112.

Sandlund O.T. 1992 - Differences in the ecology of two vendace populations separated in 1895 - Nord. J. Freshwat. Res. 67: 52-60.

Sarvala J., Helminen H., Hirvonen A. 1992 - Fecundity of vendace (Coregonus albula) in relation to year-class variations in Lake Pyhajarvi, SW-Finland - Pol. Arch. Hydrobiol. 39: 341-349.

Szczerbowski J.A. 1978 - An assessment of the growth rates of vendace, common whitefish, carp bream, roach, and zander as a benchmark for determining the marketable size - Wyd. IRS, Olsztyn 114: 1-15 (in Polish).

Szypula J. 1970 - Growth and distribution of Coregonus albula L. in Leginskie and Wydrynskie Lake - Rocz. Nauk Rol. 92-H-3: 45-60 (in Polish).

Szypula J., Wi^ski K., Rybczyk A. 2001 - Practicals in Fish Biology with MS Excel spreadsheet - Wyd. AR Szczecin, 150 p. (in Polish).

Turunen T., Salmi P., Auvinen H. 1998 - The latest changes in the Finnish lake fisheries of vendace (Coregonus albula) - Arch. Hydrobiol. Spec. Issues Advanc. Limnol. 50: 419-427.

Valkeajäervi P., Bagge P. 1993 - Larval abundance, growth and recruitment of vendace (Coregonus albula (L.) at high and low stock densities in Lake Konnevesi, Finland, in 1979-1992 - Adv. Limnol. Ergeb. Limnol. 46: 203-209.

Viljanen M. 1986 - Biology, propagation, exploitation and management of vendace (Coregonus albula L.) in Finland

- Arch. Hydrobiol. Beih. Ergebn. Limnol. 22: 73-97.

Viljanen M. 1988a - Population dynamics of vendace

(Coregonus albula L.) in Finland - Univ. Joensuu, Publications in Sciences 12: 1-19.

Viljanen M. 1988b - Relations between egg and larval abundance, spawning stock and recruitment in vendace (Coregonus albula L.) - Finnish Fish. Res. 9: 271-289.

Vysegorodcev A.A. 1977 - Sibirskaja rjapuska Coregonus albula sardinella (Valenciennes) reki Juribej (Bassejn Gydanskogo Zaliva) - Vopr. Ikhtiol. 17: 17-26 (in Russian).

Walczak J. 1953 - Vendace (Coregonus albula) from several lakes of Western Pomerania - Rocz. Nauk Rol. 67-B-1: 21-37.

Winfield I.J., Adams E.C., Fletcher M.J. 1996a - Recent introductions of the ruffe (Gymnocephalus cernuus) to three United Kingdom lakes containing Coregonus species -Ann. Zool. Fennici 33: 459-466.

WinfieldI.J., Cragg-Hine D., Fletcher J.M., CubbyP.R. 1996b

- The conservation ecology of Coregonus albula and C. lavaretus in England and Wales, UK - Conservation of Endangered Freshwater Fish in Europe: 213-223

Zawisza J., Backiel T. 1970a - Gonad development, fecundity and egg survival in Coregonus albula L. Fundamentals of Fish Biology - In: Biology of coregonid fishes (Eds) C.C. Lindsey, C.S. Woods, Univ. Manitoba Press: 363-399.

Zawisza J., Backiel T. 1970b - Vendace fecundity. Fundamentals of Fish Biology - In: Vendace management in lakes, part II - Wyd. IRS, Olsztyn 40: 8-19 (in Polish).