Acta Sci. Pol., Piscaria 4(1-2) 2005, 59-70

Acta Sci. Pol., Piscaria 4(1-2) 25, 59-7 AGE AND GROWTH RATE OF THE ROACH (Rutilus rutilus L.) FROM THE SOLINA AND THE TRESNA ( YWIECKIE LAKE) DAM RESERVOIRES Piotr Epler, W odzimierz Popek, Ewa uszczek-trojnar, Ewa Dr g-kozak, Pawe Szczerbik, Magdalena Socha Agricultural University in Crakow, Poland Abstract. Roach spawners 35 were collected during fishing carried out in the Solina dam reservoir and 256 roach spawners in the Tresna dam reservoir within 1997-21.The individual body length and body weight of the fish were measured, additionally scales were collected for the age estimation. The growth of fish were determined by empirical measurements. Coefficients of condition were estimated using the Fulton formula. The results showed that roach from the Solina reservoir was at age 3-8, with the predominated age-classes of 4+ (33.3% of the whole sample) and 5+ (39%). The roach from the Tresna reservoir was at age 2-11, and the participation of fish in the particular age-classes ranged from 6% (2+) to 13.8% (4+). The highest value of the mean annual body length increment was observed at age 4+ (3.3 cm) and the lowest at age 8+ (.6 cm) in the Solina reservoir. Similar results were obtained in case of the roach from Tresna reservoir, which showed the highest mean annual body length increment at age 4+ and the lowest at age 8+. The highest annual body weight increment of roach in Solina was recorded at age 4+ (53.9 g) and 7+ (49 g), whereas the lowest one at age 5+ (24.5 g), 6+ (26.8 g) and 8+ (8.5 g). In the case of roach from Tresna the highest annual body weight increments were noted at age 9+, 6+ and 7+ : 95., 57.3 g and 51.2 g, respectively. The values of condition coefficient were similar in both reservoires. No significant differences were observed between values of the annual body length and weight increments of the particular age-classes from the Solina and Tresna dam reservoires. Key words: age, dam reservoir, growth rate, Rutilus rutilus, Solina, Tresna INTRODUCTION The management of fisheries and angling in the dam reservoires has to be based on the ichthyological and biological studies of fish species that occur in this environment [Masty ski 1991]. One of the most important elements is determination of age and Corresponding author Adres do korespondencji: Prof. dr hab. Piotr Epler, Department of Ichthyobiology and Fisheries, Agricultural University in Cracow, Spiczakowa 6, 3-199 Kraków- -Mydlniki, Poland

6 P. Epler et al. growth rate of fish, particularly of the species dominated by quantity in the ichthyofauna composition [Heese 1992]. In the earlier ichthyological studies roach was the third species in the Solina ichtyofauna by quantity (9.2%) of fish captured with the nets, followed the bream (57.8%) and the crucian carp (16.1%), whereas it was a dominant (48-5%) in the angling catches [Bieniarz and Epler 1993]. In the ichtyofauna of Tresna dam reservoir [Epler and Bieniarz 1977] roach catches contributed 2.14% by weight of fish in the commercial catches, being the fifth species followed the bream, vimba, pikeperch and pike, whereas it was a dominant in the angling catches, contributing up 67.9% by weight of fish collected [Bieniarz et al. 199]. This species was examined in other water bodies as well [Karpi ska-walu 1961, Skóra 1964a, Wilko ska 1975], but there was a lack of data from the Solina and Tresna reservoires. The object of present paper is to determine the age and growth rate of roach, which is a very important component of ichtyofauna in the Solina and Tresna reservoires. MATERIAL AND METHODS The material to study was collected within 1997-21 from the occasional commercial catches and from angling catches performed in the Solina and Tresna ( ywieckie Lake) reservoires. A total of 35 individuals from the Solina reservoir and 256 individuals from Tresna reservoir were examined. The measurements of total length longitudo totalis (l.t.) and standard (body) length longitudo corporis (l.c.) were made to the nearest.5 cm, and individual weight was established to the nearest 5 g. From each fish the scales were collected to determine age with the Zeiss projector and measuring microscope. The growth rate of length was determined with the method of empirical measurements. The coefficient of condition k was calculated used the Fulton formula. Data on length and weight of fish body, as well as annual increments of length and weight of roach from two reservoires were compared used the non-parametric Man-Whitney test. RESULTS AND DISCUSSION Age of fish investigated ranged from 3+ to 8+ (Table 1). The greatest number of individuals (39%) was found in the 5+ age-class, then in the 4+ age-class (33.3%) and 6+ one (14.9%). The contribution of remaining age-classes covered the range from 1% (8+) to 6.7% (3+) (Table 1). The growth rate of roach from the Solina until the eighth year of life was calculated based on the body length (Table 1). The growth is irregular; the highest increments of length are attained by roach between third and fourth years of life (ca. 3.3 cm). In the consecutive years the increment oscillates around 1 cm, to Acta Sci. Pol.

Age and growth rate of the roach... 61 decrease to.6 cm in the eighth year. The mean increments of weight are also the highest between third and fourth year of life 53.9 g, in two consecutive years amount to 24.5 and 26.8 g, respectively, in the seventh year increase to 49 g, whereas in the eighth year it is only 8.5 g (Table 1). Table 1. The averages of: total length (l.t.), body length (l.c.), body weight, body length increments, body weight increments and coefficient of condition in particular ageclasses of the roach from the Solina reservoir Tabela 1. rednie: d ugo ci ca kowitej (l.t.), d ugo ci cia a (l.c.), masy cia a, przyrostów d ugo ci cia a, przyrostów masy cia a oraz wspó czynnik kondycji w poszczególnych grupach wiekowych p oci ze Zbiornika Soli skiego Age-classes Grupy wieku Percentage Udzia procentowy Mean l.t., cm rednia l.t., cm Mean l.c., cm rednia l.c., cm Mean l.c. increment, cm redni przyrost l.c., cm Mean body weight, g rednia masa cia a, g Mean body weight increment, g redni przyrost masy cia a, g Coefficient of condition Wspó czynnik kondycji III IV V VI VII VIII 6.7 33.3 39. 14.9 5.1 1. 15.8 19.9 21.3 22.3 23.5 25. 14. 17.3 18. 19.2 2.5 21.1 3.3.9 1. 1.3.6 47.3 11.2 125.7 152.5 21.5 21. 53.9 24.5 26.8 49. 8.5 1.19 1.28 1.3 1.37 1.56 1.34 The estimated coefficient of condition (k) ranges from 1.19 (3+) to 1.56 (7+). It was increasing regularly from 3+ to 7+, and decreased to 1.34 in the eighth year of life (Table 1). The condition of roach from the Solina (Table 2) is better when compared to roach from the Gocza kowice and Koz owa Góra [Skóra 1964a, b], however worse when compared to fish from the Lakes Bia e and Czarne [Stroi ski 1971]. Table 2. Comparison of condition coefficients of the roach from the Solina dam reservoir with other dam reservoires and lakes of Poland Tabela 2. Porównanie wspó czynników kondycji p oci z Soli skiego Zbiornika Zaporowego ze wspó czynnikami kondycji tego gatunku w zbiornikach zaporowych i jeziorach naturalnych Polski Age-classes Grupy wieku III IV V VI VII VIII Solina (own research badania w asne) 1.19 1.28 1.3 1.37 1.56 1.34 Gocza kowice [Skóra 1964a] 1.5 1.7 1.21 1.25 1.26 1.26 Koz owa Góra [Skóra 1964b] 1.23 1.1 1.11 1.13 1.17 Jezioro Bia e Bia e Lake [Stroi ski 1971] 1.87 1.98 1.92 1.96 2.6 Jezioro Czarne Czarne Lake [Stroi ski 1971] 1.38 1.13 1.19 1.84 1.59 1.37 Piscaria 4(1-2) 25

64 P. Epler et al. Table 3. Age, mean total length, mean body length, mean annual body length increments and body weight of the roach from the Tresna reservoir Tabela 3. Wiek, rednie d ugo ci ca kowite, rednie masy cia a, oraz rednie roczne przyrosty d ugo ci i masy cia a p oci z Tresnej Age Wiek Percentage Udzia procentowy Mean l.t., cm rednia l.t., cm Mean l.c., cm rednia l.c., cm Mean body weight, g renia masa, g Mean l.c. increments, cm rednie przyrosty l.c., cm Mean body weight increments, g rednie przyrosty masy cia a, g Coefficient of condition Wspó czynnik kondycji 2+ 3+ 4+ 5+ 6+ 7+ 8+ 9+ 1+ 11+ Total Razem 6.6 11.8 13.8 12.5 11.3 1.2 9.7 1.5 6.6 7 1 1.6 13.5 17.6 21 23.5 25.7 27 28.6 29.5 3.5 8.5 11.1 14.6 17.3 19.3 21.4 22.4 23.5 24.6 25.5 15 31.9 69.8 16 163 214 27 365 38 42 2.6 3.5 2.7 2 2.1 1 1.1 1.1.9 16.9 37.9 35.7 57.3 51.2 56 95 16 22 1.1 1.15 1.19 1.1 1.48 1.42 1.3 3 25 2 Tresna - own research - badania w asne Gocza kowice Koz owa Góra Przeczyce W gorzewskie Libiszowskie l.c., cm 15 1 5 I II III IV V VI VII VIII IX X XI Grupy wiekowe Age-classes Fig. 3. Age, mean total length, mean body length, mean annual body length increments and body weight of the roach from the Tresna reservoir Rys. 3. Wiek, rednie d ugo ci ca kowite, rednie masy cia a, oraz rednie roczne przyrosty d ugo ci i masy cia a p oci z Tresnej In the first years of life (2+ - 4+), the growth pattern of roach from the Tresna is almost identical like in other water bodies (Fig. 3). The length curve that presents the growth of roach from the Tresna indicates its irregular run with the declining Acta Sci. Pol.

Age and growth rate of the roach... 65 tendency [Karpi ska-walu 1961]. The slowing down of growth rate of roach may result from the deteriorated food connditions for these age-classes, although according to criteria given by Wilko ska [1975] the growth rate of roach from the Tresna can be considered as very good. The comparison of growth rates of body weight of roach from the Tresna reservoir and fish of this species from other water bodies (Fig. 4) shows that they are similar from the second to fourth years of life, however they differ in minus and in plus in the consecutive years. The weight increments of roach from the Tresna are globally lower when compared to roach from the Gocza kowice and Przeczyce reservoires, however higher when compared to fish from the Koz owa Góra and Lake Bia e. Mean body weight, g rednia masa cia a, g 45 4 35 3 25 2 15 1 5 Tresna - own research - dane w asne Gocza kowice Koz owa Góra Przeczyce Bia e I II III IV V VI VII VIII IX X XI XII Fig. 4. Comparison of the rate of the roach body weight growth from Tresna with the growth in dam reservoires: Gocza kowice, Koz owa Góra, Przeczyce and in Bia e lake Rys. 4. Porównanie tempa wzrostu masy cia a p oci w Tresnej ze wzrostem masy cia a tego gatunku w zbiornikach zaporowych: Gocza kowice, Koz owa Góra, Przeczyce i jeziorze Bia ym Authors of the present paper realize that data concerning growth rate of fish length, determined from the direct reading (the mean lengths calculated in age-classes) and back-calculated growth rate may be uncomparable, because the edge increment of scale overestimates the calculations. Nevertheless it seemed to be motivated, at least in some extent, by common studies with Szypu a et al. [21] on fish growth rate in the dam reservoires in Iraq, where in both methods the comparable results were obtained; however the constant high water temperature may have been a vital factor in these examinations. Bearing all facts in mind, data given in Karpi ska-walu [1961] and Heese [1992] should be treated as full years without extra +. Piscaria 4(1-2) 25

66 P. Epler et al. When analyzed the results obtained in this study it can be concluded that roach in the Tresna (Lake ywieckie) find there good environmental and developmental conditions. The population is strong, what is confirmed by the high angling captures; it can be limited by stocking the water bodies with the predatory fish species. The comparison of length and weight increments in the consecutive years of the roach life from both dam reservoires is presented in Fig. 5. Body lenght l.c., cm D ugo cia a, cm 25 2 15 1 5 Solina Tresna 3+ 4+ 5+ 6+ 7+ 8+ Body weight, g Masa cia a, g 3 25 2 15 1 5 Solina Tresna 3+ 4+ 5+ 6+ 7+ 8+ Acta Sci. Pol.

Age and growth rate of the roach... 67 l.c. increments, cm Przyrosty l.c., cm 4 3,5 3 2,5 2 1,5 1,5 Solina Tresna 3+ 4+ 5+ 6+ 7+ 8+ Body weight increments, g Przyrosty masy cia a, g 7 6 5 4 3 2 1 Solina Tresna 3+ 4+ 5+ 6+ 7+ 8+ Fig. 5. Comparison of the body length (l.c.), body weight, annual l.c. increments and annual body weight increments of the roach from the Solina and the Tresna reservoires Rys. 5. Porównanie wzrostu d ugo ci i masy cia a oraz rocznych przyrostów d ugo ci i masy cia a u p oci z Soliny i Tresnej Due to a great range of data derived from the individual measurements, a nonparametric test Man-Whitney was employed to the statistical calculations. The test showed no statistically significant differences between the growth rates of roach from the Solina and Tresna, among the age-classes compared, i.e., from 4+ to 7+. Piscaria 4(1-2) 25

68 P. Epler et al. CONCLUSIONS The roach in both dam reservoires Solina and Tresna find favourable conditions for development. Its rate of growth is close to the growth pattern of this species in other dam reservoires and higher than in the Mazurian Lakes. The population of roach is strong in the Solina and Tresna, although this species should not dominate in the submontane dam reservoires. No statistically significant differences were found in the growth patterns of roach from the Solina and Tresna reservoires. REFERENCES Bieniarz K., Epler P., Achinger J., 199. Po owy w dkarskie na ywieckim zbiorniku zaporowym [Angling catches in the ywieckie dam reservoir]. Rocz. Nauk. PZW 3, 7-14 [in Polish]. Bieniarz K., Epler P., 1993. Po owy w dkarskie na Soli skim zbiorniku zaporowym [Angling catches in the Solina dam reservoir]. Rocz. Nauk. PZW 6, 5-18 [in Polish]. Epler P., Bieniarz K., 1977. Ichtiofauna zbiornika zaporowego [Ichthyofauna of the Tresna reservoir dam]. Gospod. Ryb. 1, 8-11 [in Polish]. Heese T., 1992. Optymalizacja metody okre lania tempa wzrostu ryb za pomoc odczytów wstecznych [Optimalization of the growth rate estimation with the back-calculations method]. Monogr. Politech. Koszal. 42, 7-155 [in Polish]. Karpi ska-walu B., 1961. Wzrost p oci w jeziorach okolic W gorzowa [Growth pattern of the roach in lakes near the village W gorzewo]. Rocz. Nauk Rol. Ser. B. 77, 2, 329-392 [in Polish]. Masty ski J., 1991. Gospodarka rybacka w zbiornikach zaporowych [Fishery management in the dam reservoires]. Skrypty AR, Pozna [in Polish]. Skóra S., 1964a. Charakterystyka p oci (Rutilus rutilus L.) ze zbiornika Gocza kowickiego [The roach (Rutilus rutilus L.) from the Gocza kowice dam reservoir]. Acta Hydrobiol. 6, 351-374 [in Polish]. Skóra S., 1964b. Charakterystyka p oci (Rutilus rutilus L.) ze zbiornika w Koz owej Górze [The roach (Rutilus rutilus L.) from the Koz owa Góra dam reservoir]. Acta Hydrobiol. 6, 269-284 [in Polish]. Skóra S., 1972. The roach (Rutilus rutilus L.) from the dam reservoir in Pieczyce. Acta Hydrobiol. 14, 399-418. Stroi ski R., 1971. Wzrost lina Tinca tinca L. i p oci Rutilus rutilus L. z jezior Libiszowskich przed zasilaniem wodami kana u Wieprz-Krzna [Growth pattern of tench Tinca tinca L. and roach Rutilus rutilus L. from the Lakes Libiszowskie beneath the inflow of the Wieprz-Krzna canal waters]. Rocz. Nauk Rol. Ser. H. 92, 2, 67-85 [in Polish]. Szypu a J., Ekler P., Bartel R., Szczerbowski A., 21. Age and growth of fish in Lasek Tharthar, Razzazah and Habbaniya. Arch. Pol. Fish. 9, Supl. 1, 185-197. Wilko ska H., 1975. Ró nicowanie tempa wzrostu p oci (Rutilus rutilus L.) w jeziorach polskich na tle warunków rodowiskowych [Differentiation of growth rate of roach (Rutilus rutilus L.) in Polish lakes against the environmental background]. Rocz. Nauk Rol. Ser. H. 92, 7, 7-3 [in Polish]. Acta Sci. Pol.

Age and growth rate of the roach... 69 WIEK I WZROST P OCI (Rutilus rutilus L.) ZE ZBIORNIKÓW ZAPOROWYCH SOLINA I TRESNA (JEZIORO YWIECKIE) Streszczenie. Z od owów gospodarczych i w dkarskich w zbiornikach zaporowych Solina i Tresna pozyskano w latach 1997-21 odpowiednio 35 i 256 p oci. Wykonano indywidualnie pomiary ichtiologiczne oraz pobrano uski celem okre lenia wieku. Wzrost ryb oznaczono metod pomiarów rzeczywistych. Obliczono kondycj badanych p oci za pomoc wzoru Fultona. Wiek p oci z Soliny waha si od 3 do 8 lat, przy czym dominuj cymi by y roczniki 4+ (33,3% wszystkich badanych ryb) i rocznik 5+ (39% ryb). Wiek p oci ze zbiornika Tresna waha si od 2 do 11 lat, a udzia ryb w poszczególnych grupach wiekowych waha si od 6% (2+) do 13,8 % (4+). redni przyrost cia a by najwy szy w 4. roku ycia (3,3 cm), a najni szy w 8. (,6 cm) w zbiorniku Soli skim. Podobne wyniki uzyskano w przypadku p oci z Tresnej, gdzie najwy sze przyrosty d ugo ci cia a przypad y na 4. rok ycia, a najni sze na 11. Najwi ksze roczne przyrosty masy cia a p oci z Soliny mia y miejsce w 4 (53,9 g) oraz w 7 roku (49 g), a najmniejsze w 5. i 6. roku ycia. W przypadku p oci z Tresnej najwi ksze roczne przyrosty masy cia a wykazano w 9., 6. i 7. roku ycia, odpowiednio: 95, 57,3 oraz 51,2 g. Warto ci wspó czynnika kondycji p oci by y zbli one w obu zbiornikach. Porównanie masy cia a oraz rocznych d ugo ci i masy cia poszczególnych roczników p oci z Soliny i Tresnej nie wykaza o ró nic statystycznie istotnych. S owa kluczowe: Rutilus rutilus, Solina, tempo wzrostu, Tresna, wiek, zbiornik zaporowy Accepted for print Zaakceptowano do druku: 22.6.25 Piscaria 4(1-2) 25