- Email: [email protected]
Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin
REPBIO-152; No. of Pages 4 reproductive biology xxx (2015) xxx–xxx
Available online at www.sciencedirect.com
ScienceDirect journal homepage: http://www.elsevier.com/locate/repbio
Short Communication
Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin Lidia Marszał *, Dagmara Błońska Department of Ecology and Vertebrate Zoology, University of Lodz, Lodz, Poland
article info
abstract
Article history:
The aim of the current study was to examine whether environmental conditions may
Received 8 September 2014
explain interpopulation variation in fecundity and egg size of the spirlin from two rivers of
Received in revised form
the Vistula River basin. The obtained results indicated that the reproductive performance,
12 March 2015
including the gonadosomatic index, was similar in both rivers and fecundity increased with
Accepted 24 March 2015
total length of females. The observed differences in water temperatures and flow speed
Available online xxx
between the rivers were too small to cause discernible differences in the reproductive performance of fish.
Keywords:
# 2015 Published by Elsevier Sp. z o.o. on behalf of Society for Biology of Reproduction &
Fecundity
the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in
Gonadosomatic index
Olsztyn.
Oocyte size Threatened species Poland
1.
Introduction
Spirlin Alburnoides bipunctatus (Bloch, 1782) is a small cyprinid inhabitating sub-montane streams and rivers characterized by gravel and sand substrata. Due to being rare and endangered in Poland (it is listed in the Polish Red Book), the spirlin is protected by law [1]. It prefers shallow, clear, well oxygenated and fast-flowing waters for reproduction. One well-known reproductive trait of this species is batch spawning [2,3], and although several papers on spirlin biology have been published in recent years [2,4,5], some other reproductive aspects
are still obscure, especially those concerning Polish populations [6]. The results of several studies have shown that variations in fish fecundity and egg size are dependent on phenotypic plasticity, which, however, are caused only by major changes in environmental factors [7]. The aim of the current study was to examine whether the reproductive traits of spirlin are influenced by local environmental factors. For this purpose, spirlin populations from two rivers of the Vistula basin characterized by different water temperatures and flow regimes were examined. If the presence of interpopulation differences in the reproductive traits was confirmed then the
* Corresponding author at: Department of Ecology and Vertebrate Zoology, University of Lodz, Banacha 12/16 Str., 90-237 Lodz, Poland. Tel.: +48 42 6354433; fax: +48 42 6655817. E-mail address: [email protected] (L. Marszał). http://dx.doi.org/10.1016/j.repbio.2015.03.004 1642-431X/# 2015 Published by Elsevier Sp. z o.o. on behalf of Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn.
Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004
REPBIO-152; No. of Pages 4
2
reproductive biology xxx (2015) xxx–xxx
differences might indicate adaptations of spirlin individuals to local conditions.
2.
Materials and methods
Specimens of spirlin were collected (n = 204; Table 1) using electrofishing from the Skrwa Prawa River (N 528380 , E 198340 , slope 1.07%), 117 km long tributary of the Vistula River, in May of years 2011 and 2014, and from the Drzewiczka River (N 518270 , E 208280 , slope 1.13%), 81 km long tributary of the Pilica River (left tributary of the Vistula River), in May of 1999. Both rivers have natural character in most of their courses; however, the Drzewiczka has a dam reservoir (Drzewieckie Lake), and the study site was located below it. A different water temperature (database of Voivodship Inspectorate for Environmental Protection, Warsaw) is the most important difference between rivers, because Skrwa Prawa is fed with deeper located, and thus colder, layers of groundwater than those that feed Drzewiczka. After being caught, fish specimens were anaesthetized using clove oil and fixed in 5% formaldehyde. All actions were carried out having permissions of the Local Ethics Committee (35/ŁB555/2011) and of the General Directorate of Environmental Protection (DOP-OZGIZ.6401.11.2011.ls). The measured parameters included: total length (TL; accuracy: 1 mm), standard length (SL; accuracy: 1 mm), body (W; accuracy: 0.01 g) and gonads weight (GW; accuracy: 0.01 g). The gonads were examined under the binocular to determine the sex and stage of maturation. The maturity status of female spirlin was determined using a visual observation of the ovary's color and microscopic inspection of vitellogenic oocytes. Ovaries contained: (1) immature – small, translucent, (2) maturing – larger, yellowish, translucent or opaque, and (3) mature – large, yellow, opaque oocytes [8]. Subsamples were taken from anterior, middle and posterior portions of the ovarian lobe, and oocytes in each subsample were counted. Diameters of 50 randomly selected ova per female were measured. Polymodal diagrams of diameter frequency were decomposed to normal distributions using the Bhattacharya's method [9] and the mean size ( SD) of ova was estimated with the FiSAT software [10]. Gonadosomatic index – defined as GSI = 100 weight of gonad (g)/total body weight (g) – was calculated for all individuals in which sex could be identified, while absolute (Fa) and relative (Fr) fecundity only for mature females [7]. Regression analysis of TL and W as well as of TL
and GW was estimated separately for females and males from both sampling sites. The results were submitted to analysis of covariance (ANCOVA) followed by Tukey test for multiple comparisons. The length–weight relationships were also tested to find if they were isometric (b = 3) when an increase in size and weight of fish during growth occurs at the same rate, or allometric (b 6¼ 3) when relationship between these variables deviates from isometry [11]. Differences in water temperature between studied rivers as well as in TL, Fr and egg diameter of females and GSI values of both sexes between localities were assessed using Student's t-test. All statistical analyses were performed using the software EXCEL 2007 and Statistica v. 10.
3.
Results and discussion
The rivers exhibited significant difference in water temperature ( p = 0.034) with mean annual values of 11.1 8C and 12.2 8C for Skrwa Prawa and Drzewiczka, respectively. Significant differences were obtained from a comparison of the length– weight relationships between males and females collected in both localities (F3;130 = 2.910, p = 0.037; Suppl. Table 1). There were no differences between localities, only between sexes. The b-values of the relationships imply that the body shapes of males and females display positive allometric form as a consequence of resource allocation to gonads during the reproductive season. Similar results were obtained for Iranian population [4]. A comparison of the relationship between TL and GW showed differences between sexes as well as localities (F3;108 = 13.14, p < 0.0001; Suppl. Table 2). Contrary to males, females from both localities differed significantly in TL ( p < 0.0001) with a higher mean value ( SD) for Drzewiczka than Skrwa Prawa (98 9.18 and 86 5.54 mm, respectively). Supplementary Tables S1 and S2 related to this article can be found, in the online version, at doi:10.1016/j.repbio.2015.03. 004. The mean value of GSI ( SD) was 11.75 4.32 for females and 6.47 2.08 for males in Skrwa Prawa and 18.6 4.41 and 7.01 2.06, in Drzewiczka, respectively. The GSI female values differed ( p < 0.0001) between the two rivers. The GSI was positively related to TL for all females (linear regression equation: GSI = 0.2934 TL 11.811, r2 = 0.2883). Similar or higher GSI values in May were reported for spirlin from Czech [2] and Turkish [12] populations, while Iranian population was
Table 1 – Characteristics of spirlin material collected in the studied rivers. River
Sex
n
Total body length (mm)
Body weight (g)
Mean SD
Range
Mean SD
Range
Skrwa Prawa
F M J
31 34 20
85.8 9.3 79.7 8.1 52.7 12.5
73–113 62–96 29–69
6.7 2.8 5.1 1.5 1.4 0.9
2.9–17.2 2.4–8.1 0.2–3.0
Drzewiczka
F M J
25 48 46
95.9 7.5 74.0 18.2 48.0 6.6
77–111 48–110 37–72
9.9 2.6 4.7 3.5 1.1 0.7
4.2–15.9 0.9–14.0 0.5–4.1
n, number of individuals; SD, standard deviation; F, female; M, male; J, juvenile.
Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004
REPBIO-152; No. of Pages 4 reproductive biology xxx (2015) xxx–xxx
characterized by lower GSI values [4,5]. Batch spawners may have a relatively low GSI due to more frequent acts of spawning [7]. Absolute fecundity (Fa) ranged between 308 and 3831 eggs (mean 1545 657) for fish from Skrwa Prawa (n = 31), and from 1191 to 3135 (mean 2023 523) for Drzewiczka (n = 22). The maximum Fa of 3831 eggs was recorded for the largest female collected (TL = 113 mm; W = 17.02 g, Skrwa Prawa). The relationship between TL and Fa was significant in females from both sampled rivers ( p < 0.0001; Suppl. Fig. 1). There was no difference in Fa between females from both localities (F1;49 = 0.3095, p = 0.580). For the whole set of females Fa linear regression was log Fa = 2.580 log TL 1.819; r2 = 0.721. Relative fecundity (Fr) ranged between 36 and 413 (mean 239 65) in Skrwa Prawa and between 136 and 232 (mean 192 28) in Drzewiczka. Mean Fr values differed significantly between populations ( p = 0.039). Relationship between Fr and TL was significant for females from Skrwa Prawa (r2 = 0.133, p = 0.043), similarly as for pooled data (r2 = 0.153, p = 0.004). Comparing the mean Fa for female spirlin in spawning season, similar values were noted in the Iranian populations of Alburnoides sp. [4,5], while higher values for Czech populations [2]. Oocyte
3
diameter ranged from 0.091 to 1.818 (mean 0.881 0.178) and from 0.524 to 1.667 (mean 1.106 0.09) in females from Skrwa Prawa and Drzewiczka, respectively. Egg diameter differed between females from the studied localities ( p < 0.0001). The fact that in some species mean egg size increases with female length was also pointed by Wootton [7]. Frequency diagrams of oocyte size were bimodal (Fig. 1a), which suggests batch spawning. Mature oocytes did not differ between populations ( p = 0.855); however, maturing oocytes were larger in females from Drzewiczka ( p < 0.0001). Both maturing and mature oocytes show significant relationship with female total length (Fig. 1b). Batch fecundity (i.e. the number of eggs produced per spawning) depends on age and size of females. Besides, the fecundity can vary from year to year in a population as a result of environmental factors such as temperature [7]. According to the results obtained by Polačik and Kovač [2] females collected during the spawning season showed diverse stages of oocyte development. In the present study, most females contained two oocyte size-classes, except two females with 3 size-classes from Skrwa Prawa. Besides, we found a female (TL = 97 mm, GSI = 5.35) containing only the largest size-class eggs (mean 1.48 mm, range 0.77–1.82 mm). These oocytes can be regarded
Fig. 1 – Reproductive characteristics of spirlin. (a) Frequency distribution of oocyte size. Theoretical distributions for Skrwa Prawa and for Drzewiczka were obtained by decomposition of polymodal distributions using the Bhattacharya method (n = 4440). (b) Regression analysis of small (maturing) and large (mature) oocyte diameters and total length of female (n = 51). Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004
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as a single spawning batch (308 eggs in total) and it is worth to emphasize that this female ovary contained no other oocytes. According to Wootton [7], large eggs can only be produced at the expense of a reduced batch fecundity, which means that fecundity and mean egg size are inversely correlated. The case of this exceptional female (excluded from Fa and Fr analysis) can be regarded as a very rare situation, because individual females of the same size do differ in their batch fecundities and even for the same female batch fecundities can vary within the same breeding season [7]. On the other hand, taking into consideration the time of spirlin spawning season (May) the female can serve as an example of synchronous spawning, an alternative spawning strategy. Consequently, it is possible that infrequent specimens in a population may represent determinate fecundity, the example of this being the female, which, to the best of our knowledge, might be the first such case recorded. Supplementary Fig. S1 related to this article can be found, in the online version, at doi:10.1016/j.repbio.2015.03.004. The presented results showed that a large part of the variations in female GSI, Fa and egg size among populations resulted from interpopulation variation in TL. The studied populations exhibited a similar reproductive performance in spite of being subjected to different environmental factors, such as water temperature and flow regime. Thus, the range of environmental conditions that spirlin is able to cope with in the studied streams is too narrow to cause discernible modifications in fecundity. Although the higher water temperature caused no difference in spirlin fecundity, it significantly impacted female total length.
Acknowledgements The present study was financed by an internal grant from the University of Lodz. We would like to thank M. Przybylski for valuable comments and suggestions on the statistical processing of data and Ł. Głowacki for improving the English text. Thanks are due to our colleagues from the department for their assistance in the field research.
references
[1] Witkowski A, Kotusz J, Przybylski M. The degree of threat to the freshwater ichthyofauna of Poland: red list of fishes and lampreys – situation in 2009. Chrońmy Przyr Ojcz 2009;65 (1):33–52 (in Polish). [2] Polačik M, Kováč V. Fecundity and annual course of maturation in spirlin, Alburnoides bipunctatus. Folia Zool 2006;55(4):399–410. [3] Bless R. Reproduction and habitat preference of the threatened spirlin (Alburnoides bipunctatus Bloch) and soufie (Leuciscus souffia Risso) under laboratory conditions (Teleostei: Cyprinidae). In: Kirchhofer A, Hefti D, editors. Conservation of Endangered Freshwater Fish in Europe. Basel, Switzerland: Birkhauser Verlag; 1996. p. 249–58. [4] Patimar R, Zare M, Hesam M. On the life of spirlin Alburnoides bipunctatus (Bloch, 1782) in the qanat of Uzineh, northern Iran. Turk J Zool 2012;36(3):383–93. [5] Seifali M, Arshad A, Esmaeili HR, Kiabi BH, Yazdani Moghaddam F, Fardad N. Fecundity and maturation of South Caspian spirlin Alburnoides sp. (Actinopterygii: Cypriniade) from Iran. Iran J Sci Technol 2012;A2:181–7. [6] Skóra S. The cyprinid Alburnus bipunctatus Bloch from the basins of the rivers Upper San and Dunajec. Acta Hydrobiol 1972;14(2):173–204 (in Polish). [7] Wootton RJ. Ecology of teleost fishes. Netherlands: Springer; 1990. p. 159–94 [chapter 7]. [8] Thompson EJ, Hannah RW. Using cross-dating techniques to validate ages of aurora rockfish (Sebastes aurora): estimates of age, growth and female maturity. Environ Biol Fish 2010;88:77–88. [9] Bhattacharya CG. A simple method of resolution of a distribution into Gaussian components. Biometrics 1967;23:115–35. [10] Gayanilo FC, Sparre P, Pauly D. The FAO-ICLARM Stock Assessment Tools (FiSAT) user's guide. Roma: FAO Computerized Information Series Fisheries; 1994. p. 1–126. [11] Zar JH. Biostatistical analysis. New Jersey: Pearson PrenticeHall; 1984. [12] Yildirim A, Erdoğan O, Türkmen M, Demir BC. The investigation of some reproduction characteristics of the Alburnoides bipunctatus fasciatis (Nordman, 1840) living in Oltu stream, Çoruh Basin. Turk J Vet Anim Sci 1999;23 (4):679–86 (in Turkish).
Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004
Available online at www.sciencedirect.com
ScienceDirect journal homepage: http://www.elsevier.com/locate/repbio
Short Communication
Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin Lidia Marszał *, Dagmara Błońska Department of Ecology and Vertebrate Zoology, University of Lodz, Lodz, Poland
article info
abstract
Article history:
The aim of the current study was to examine whether environmental conditions may
Received 8 September 2014
explain interpopulation variation in fecundity and egg size of the spirlin from two rivers of
Received in revised form
the Vistula River basin. The obtained results indicated that the reproductive performance,
12 March 2015
including the gonadosomatic index, was similar in both rivers and fecundity increased with
Accepted 24 March 2015
total length of females. The observed differences in water temperatures and flow speed
Available online xxx
between the rivers were too small to cause discernible differences in the reproductive performance of fish.
Keywords:
# 2015 Published by Elsevier Sp. z o.o. on behalf of Society for Biology of Reproduction &
Fecundity
the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in
Gonadosomatic index
Olsztyn.
Oocyte size Threatened species Poland
1.
Introduction
Spirlin Alburnoides bipunctatus (Bloch, 1782) is a small cyprinid inhabitating sub-montane streams and rivers characterized by gravel and sand substrata. Due to being rare and endangered in Poland (it is listed in the Polish Red Book), the spirlin is protected by law [1]. It prefers shallow, clear, well oxygenated and fast-flowing waters for reproduction. One well-known reproductive trait of this species is batch spawning [2,3], and although several papers on spirlin biology have been published in recent years [2,4,5], some other reproductive aspects
are still obscure, especially those concerning Polish populations [6]. The results of several studies have shown that variations in fish fecundity and egg size are dependent on phenotypic plasticity, which, however, are caused only by major changes in environmental factors [7]. The aim of the current study was to examine whether the reproductive traits of spirlin are influenced by local environmental factors. For this purpose, spirlin populations from two rivers of the Vistula basin characterized by different water temperatures and flow regimes were examined. If the presence of interpopulation differences in the reproductive traits was confirmed then the
* Corresponding author at: Department of Ecology and Vertebrate Zoology, University of Lodz, Banacha 12/16 Str., 90-237 Lodz, Poland. Tel.: +48 42 6354433; fax: +48 42 6655817. E-mail address: [email protected] (L. Marszał). http://dx.doi.org/10.1016/j.repbio.2015.03.004 1642-431X/# 2015 Published by Elsevier Sp. z o.o. on behalf of Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn.
Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004
REPBIO-152; No. of Pages 4
2
reproductive biology xxx (2015) xxx–xxx
differences might indicate adaptations of spirlin individuals to local conditions.
2.
Materials and methods
Specimens of spirlin were collected (n = 204; Table 1) using electrofishing from the Skrwa Prawa River (N 528380 , E 198340 , slope 1.07%), 117 km long tributary of the Vistula River, in May of years 2011 and 2014, and from the Drzewiczka River (N 518270 , E 208280 , slope 1.13%), 81 km long tributary of the Pilica River (left tributary of the Vistula River), in May of 1999. Both rivers have natural character in most of their courses; however, the Drzewiczka has a dam reservoir (Drzewieckie Lake), and the study site was located below it. A different water temperature (database of Voivodship Inspectorate for Environmental Protection, Warsaw) is the most important difference between rivers, because Skrwa Prawa is fed with deeper located, and thus colder, layers of groundwater than those that feed Drzewiczka. After being caught, fish specimens were anaesthetized using clove oil and fixed in 5% formaldehyde. All actions were carried out having permissions of the Local Ethics Committee (35/ŁB555/2011) and of the General Directorate of Environmental Protection (DOP-OZGIZ.6401.11.2011.ls). The measured parameters included: total length (TL; accuracy: 1 mm), standard length (SL; accuracy: 1 mm), body (W; accuracy: 0.01 g) and gonads weight (GW; accuracy: 0.01 g). The gonads were examined under the binocular to determine the sex and stage of maturation. The maturity status of female spirlin was determined using a visual observation of the ovary's color and microscopic inspection of vitellogenic oocytes. Ovaries contained: (1) immature – small, translucent, (2) maturing – larger, yellowish, translucent or opaque, and (3) mature – large, yellow, opaque oocytes [8]. Subsamples were taken from anterior, middle and posterior portions of the ovarian lobe, and oocytes in each subsample were counted. Diameters of 50 randomly selected ova per female were measured. Polymodal diagrams of diameter frequency were decomposed to normal distributions using the Bhattacharya's method [9] and the mean size ( SD) of ova was estimated with the FiSAT software [10]. Gonadosomatic index – defined as GSI = 100 weight of gonad (g)/total body weight (g) – was calculated for all individuals in which sex could be identified, while absolute (Fa) and relative (Fr) fecundity only for mature females [7]. Regression analysis of TL and W as well as of TL
and GW was estimated separately for females and males from both sampling sites. The results were submitted to analysis of covariance (ANCOVA) followed by Tukey test for multiple comparisons. The length–weight relationships were also tested to find if they were isometric (b = 3) when an increase in size and weight of fish during growth occurs at the same rate, or allometric (b 6¼ 3) when relationship between these variables deviates from isometry [11]. Differences in water temperature between studied rivers as well as in TL, Fr and egg diameter of females and GSI values of both sexes between localities were assessed using Student's t-test. All statistical analyses were performed using the software EXCEL 2007 and Statistica v. 10.
3.
Results and discussion
The rivers exhibited significant difference in water temperature ( p = 0.034) with mean annual values of 11.1 8C and 12.2 8C for Skrwa Prawa and Drzewiczka, respectively. Significant differences were obtained from a comparison of the length– weight relationships between males and females collected in both localities (F3;130 = 2.910, p = 0.037; Suppl. Table 1). There were no differences between localities, only between sexes. The b-values of the relationships imply that the body shapes of males and females display positive allometric form as a consequence of resource allocation to gonads during the reproductive season. Similar results were obtained for Iranian population [4]. A comparison of the relationship between TL and GW showed differences between sexes as well as localities (F3;108 = 13.14, p < 0.0001; Suppl. Table 2). Contrary to males, females from both localities differed significantly in TL ( p < 0.0001) with a higher mean value ( SD) for Drzewiczka than Skrwa Prawa (98 9.18 and 86 5.54 mm, respectively). Supplementary Tables S1 and S2 related to this article can be found, in the online version, at doi:10.1016/j.repbio.2015.03. 004. The mean value of GSI ( SD) was 11.75 4.32 for females and 6.47 2.08 for males in Skrwa Prawa and 18.6 4.41 and 7.01 2.06, in Drzewiczka, respectively. The GSI female values differed ( p < 0.0001) between the two rivers. The GSI was positively related to TL for all females (linear regression equation: GSI = 0.2934 TL 11.811, r2 = 0.2883). Similar or higher GSI values in May were reported for spirlin from Czech [2] and Turkish [12] populations, while Iranian population was
Table 1 – Characteristics of spirlin material collected in the studied rivers. River
Sex
n
Total body length (mm)
Body weight (g)
Mean SD
Range
Mean SD
Range
Skrwa Prawa
F M J
31 34 20
85.8 9.3 79.7 8.1 52.7 12.5
73–113 62–96 29–69
6.7 2.8 5.1 1.5 1.4 0.9
2.9–17.2 2.4–8.1 0.2–3.0
Drzewiczka
F M J
25 48 46
95.9 7.5 74.0 18.2 48.0 6.6
77–111 48–110 37–72
9.9 2.6 4.7 3.5 1.1 0.7
4.2–15.9 0.9–14.0 0.5–4.1
n, number of individuals; SD, standard deviation; F, female; M, male; J, juvenile.
Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004
REPBIO-152; No. of Pages 4 reproductive biology xxx (2015) xxx–xxx
characterized by lower GSI values [4,5]. Batch spawners may have a relatively low GSI due to more frequent acts of spawning [7]. Absolute fecundity (Fa) ranged between 308 and 3831 eggs (mean 1545 657) for fish from Skrwa Prawa (n = 31), and from 1191 to 3135 (mean 2023 523) for Drzewiczka (n = 22). The maximum Fa of 3831 eggs was recorded for the largest female collected (TL = 113 mm; W = 17.02 g, Skrwa Prawa). The relationship between TL and Fa was significant in females from both sampled rivers ( p < 0.0001; Suppl. Fig. 1). There was no difference in Fa between females from both localities (F1;49 = 0.3095, p = 0.580). For the whole set of females Fa linear regression was log Fa = 2.580 log TL 1.819; r2 = 0.721. Relative fecundity (Fr) ranged between 36 and 413 (mean 239 65) in Skrwa Prawa and between 136 and 232 (mean 192 28) in Drzewiczka. Mean Fr values differed significantly between populations ( p = 0.039). Relationship between Fr and TL was significant for females from Skrwa Prawa (r2 = 0.133, p = 0.043), similarly as for pooled data (r2 = 0.153, p = 0.004). Comparing the mean Fa for female spirlin in spawning season, similar values were noted in the Iranian populations of Alburnoides sp. [4,5], while higher values for Czech populations [2]. Oocyte
3
diameter ranged from 0.091 to 1.818 (mean 0.881 0.178) and from 0.524 to 1.667 (mean 1.106 0.09) in females from Skrwa Prawa and Drzewiczka, respectively. Egg diameter differed between females from the studied localities ( p < 0.0001). The fact that in some species mean egg size increases with female length was also pointed by Wootton [7]. Frequency diagrams of oocyte size were bimodal (Fig. 1a), which suggests batch spawning. Mature oocytes did not differ between populations ( p = 0.855); however, maturing oocytes were larger in females from Drzewiczka ( p < 0.0001). Both maturing and mature oocytes show significant relationship with female total length (Fig. 1b). Batch fecundity (i.e. the number of eggs produced per spawning) depends on age and size of females. Besides, the fecundity can vary from year to year in a population as a result of environmental factors such as temperature [7]. According to the results obtained by Polačik and Kovač [2] females collected during the spawning season showed diverse stages of oocyte development. In the present study, most females contained two oocyte size-classes, except two females with 3 size-classes from Skrwa Prawa. Besides, we found a female (TL = 97 mm, GSI = 5.35) containing only the largest size-class eggs (mean 1.48 mm, range 0.77–1.82 mm). These oocytes can be regarded
Fig. 1 – Reproductive characteristics of spirlin. (a) Frequency distribution of oocyte size. Theoretical distributions for Skrwa Prawa and for Drzewiczka were obtained by decomposition of polymodal distributions using the Bhattacharya method (n = 4440). (b) Regression analysis of small (maturing) and large (mature) oocyte diameters and total length of female (n = 51). Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004
REPBIO-152; No. of Pages 4
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as a single spawning batch (308 eggs in total) and it is worth to emphasize that this female ovary contained no other oocytes. According to Wootton [7], large eggs can only be produced at the expense of a reduced batch fecundity, which means that fecundity and mean egg size are inversely correlated. The case of this exceptional female (excluded from Fa and Fr analysis) can be regarded as a very rare situation, because individual females of the same size do differ in their batch fecundities and even for the same female batch fecundities can vary within the same breeding season [7]. On the other hand, taking into consideration the time of spirlin spawning season (May) the female can serve as an example of synchronous spawning, an alternative spawning strategy. Consequently, it is possible that infrequent specimens in a population may represent determinate fecundity, the example of this being the female, which, to the best of our knowledge, might be the first such case recorded. Supplementary Fig. S1 related to this article can be found, in the online version, at doi:10.1016/j.repbio.2015.03.004. The presented results showed that a large part of the variations in female GSI, Fa and egg size among populations resulted from interpopulation variation in TL. The studied populations exhibited a similar reproductive performance in spite of being subjected to different environmental factors, such as water temperature and flow regime. Thus, the range of environmental conditions that spirlin is able to cope with in the studied streams is too narrow to cause discernible modifications in fecundity. Although the higher water temperature caused no difference in spirlin fecundity, it significantly impacted female total length.
Acknowledgements The present study was financed by an internal grant from the University of Lodz. We would like to thank M. Przybylski for valuable comments and suggestions on the statistical processing of data and Ł. Głowacki for improving the English text. Thanks are due to our colleagues from the department for their assistance in the field research.
references
[1] Witkowski A, Kotusz J, Przybylski M. The degree of threat to the freshwater ichthyofauna of Poland: red list of fishes and lampreys – situation in 2009. Chrońmy Przyr Ojcz 2009;65 (1):33–52 (in Polish). [2] Polačik M, Kováč V. Fecundity and annual course of maturation in spirlin, Alburnoides bipunctatus. Folia Zool 2006;55(4):399–410. [3] Bless R. Reproduction and habitat preference of the threatened spirlin (Alburnoides bipunctatus Bloch) and soufie (Leuciscus souffia Risso) under laboratory conditions (Teleostei: Cyprinidae). In: Kirchhofer A, Hefti D, editors. Conservation of Endangered Freshwater Fish in Europe. Basel, Switzerland: Birkhauser Verlag; 1996. p. 249–58. [4] Patimar R, Zare M, Hesam M. On the life of spirlin Alburnoides bipunctatus (Bloch, 1782) in the qanat of Uzineh, northern Iran. Turk J Zool 2012;36(3):383–93. [5] Seifali M, Arshad A, Esmaeili HR, Kiabi BH, Yazdani Moghaddam F, Fardad N. Fecundity and maturation of South Caspian spirlin Alburnoides sp. (Actinopterygii: Cypriniade) from Iran. Iran J Sci Technol 2012;A2:181–7. [6] Skóra S. The cyprinid Alburnus bipunctatus Bloch from the basins of the rivers Upper San and Dunajec. Acta Hydrobiol 1972;14(2):173–204 (in Polish). [7] Wootton RJ. Ecology of teleost fishes. Netherlands: Springer; 1990. p. 159–94 [chapter 7]. [8] Thompson EJ, Hannah RW. Using cross-dating techniques to validate ages of aurora rockfish (Sebastes aurora): estimates of age, growth and female maturity. Environ Biol Fish 2010;88:77–88. [9] Bhattacharya CG. A simple method of resolution of a distribution into Gaussian components. Biometrics 1967;23:115–35. [10] Gayanilo FC, Sparre P, Pauly D. The FAO-ICLARM Stock Assessment Tools (FiSAT) user's guide. Roma: FAO Computerized Information Series Fisheries; 1994. p. 1–126. [11] Zar JH. Biostatistical analysis. New Jersey: Pearson PrenticeHall; 1984. [12] Yildirim A, Erdoğan O, Türkmen M, Demir BC. The investigation of some reproduction characteristics of the Alburnoides bipunctatus fasciatis (Nordman, 1840) living in Oltu stream, Çoruh Basin. Turk J Vet Anim Sci 1999;23 (4):679–86 (in Turkish).
Please cite this article in press as: Marszał L, Błońska D, Reproductive traits of the spirlin Alburnoides bipunctatus in the Vistula River basin. Reprod Biol (2015), http://dx.doi.org/10.1016/j.repbio.2015.03.004