Reproduction biology of pikeperch (Sander lucioperca (L.)) – a review

Abstract –  The present review focuses on the reproduction biology of pikeperch ( Sander lucioperca (L.)). Aspects like maturity, fecundity, spawning migrations, spawning habitats, onset of spawning, and development time of eggs were reviewed. The onset of maturity is reached at younger age in southern than northern populations due to higher growth rate in the south. Males mature at smaller size and are on average younger than females. Absolute fecundity is closely related to the length and weight, but no clear relationship could be found between relative fecundity and length. Statistically significant relationships were found between the onset of spawning and latitude, and between the duration of the development time of eggs and stable water temperature. Near the southern limits of distribution, the onset of spawning is in February while near the northern limits it is in June. The interannual variability in fecundity and in the onset of maturity and further the factors affecting them have not been studied much. Furthermore, it is not known whether these variations could affect the population dynamics of pikeperch. Little is also known about the actual spawning behaviour of pikeperch in natural habitats. This is probably due to the typical spawning habitats located at 1–3 m depth in waters with high turbidity and low visibility. Even though the homing behaviour to the same spawning areas is well developed in adults, it is not known whether the adults were actually born in the same area.     

Out-of-season spawning of cultured pikeperch [Sander lucioperca (L.)]

The aim of this study was to determine the effectiveness of out‐of‐season spawning of cultivated pikeperch (fish that were reared from the larval stage in re‐circulating systems and fed commercial feed exclusively) stimulated hormonally with human chorionic gonadotropin (hCG). The impact of fish age (2+ and 3+) and hormone dosage [200 or 400 IU hCG kg⁻¹ body weight (BW)] on spawning was analysed and expressed as the share of stripped females, commercial fecundity (% BW) and survival of embryos until the eyed‐egg stage (EES index). The possibility of utilizing changes in female pikeperch body weight (CBW index) that are observed following hormone injections as an additional indicator for determining maturity was also investigated. The age and hormone dosage were not noted to have a significant impact on the number of stripped females (≥80% on all groups), the latency period (90–100 h), commercial fecundity (11.3–13.3% BW) or the values of the EES index (61–73%; P>0.05). The mean value of EES from the 3+ age group females was higher than that in the 2+ females, and the interaction between the tested factors (fish age and hormone dosage) wasstatistically significant (P<0.05). In the fish from the control group (injected with a 0.9% NaCl solution), no progress was noted in the maturation of oocytes and no eggs were obtained from any female. It was noted that these females lost BW over the course of the subsequent 24 h of the measurements (P<0.05). In the groups of females that were stimulated hormonally, the opposite phenomenon was observed; in these groups, the CBW index increased significantly between 48 and 96 h following hormone injection. The value of the CBW index was not noted to have been statistically significantly determined by either hormone dose or fish age (P>0.05). The regression equations that described the dependence between CBW and the oocyte maturity stage were highly significant statistically, and the determination coefficient R² assumed a value of 0.76. The most significant increase in BW was related to the oocytes achieving maturity stage III. The BW of pikeperch females with oocytes in this stage was 103% higher than the initial BW. This might be a valuable and useful tool for determining maturity in females of this fish species.     

Light intensity preference of juvenile pikeperch Sander lucioperca (L.)

Light intensity preference of the pikeperch was tested in 1‐m² tanks divided into four lateral compartments with a hole in the middle to allow the fish to move between compartments. Two experiments were carried out with both 0+ and 1+ pikeperch: one testing intensities from 25 to 300 lx and the other from 1 to 50 lx. Light preference was observed individually for 5 days at 8, 11, 14 and 17 h. On the first and fifth day, the preference was tested without differences in light intensity (control). In both experiments, both age groups showed preference for the lowest available light intensity. Preference for low light intensity in pikeperch may be related to innate activity and feeding behaviour and to avoidance of harmful effects of light. It is suggested that under aquaculture operations, pikeperch should be reared under very dim conditions.     

Conventional and molecular cytogenetics of the pikeperch (Sander lucioperca L.)

Pikeperch (Sander lucioperca L.) is a percid fish species of high commercial value and potential for being aquacultured in Europe. As such, pikeperch needs to be karyologically studied with special attention dedicated to arrangement of the homologous chromosomes into pairs and chromosomal location of the chosen DNA sequences. The karyotype of the pikeperch consists of 48 small chromosomes: One pair of metacentric chromosomes, 15 pairs of submetacentric chromosomes and eight pairs of subtelo‐acrocentric chromosomes (FN = 80). Original data on the chromosomal distribution of early and late replication regions, segments resistant to AluI, DdeI, HinfI and HaeIII restriction endonucleases and identification of the C‐banded heterochromatin presented herein have been used to arrange pikeperch chromosomes into the karyotype. After Primed in situ labeling (PRINS) technique with primers enabling amplification of 5S rDNA sequences, hybridization spots observed on the short (p) arms of two the largest pikeperch submetacentric chromosomes (no. 2). Fluorescence in situ hybridization (FISH) with telomeric PNA (Peptide Nucleic Acid) probe enabled recognition of the conservative telomeric DNA sequences on the pikeperch chromosomes. No interstitial signals were observed. The specimens studied did not show any morphologically differentiated sex chromosomes.     

Correction to: Maintenance requirement and utilisation efficiency of energy and protein for ongrowing pikeperch (Sander lucioperca (L.))

Aquaculture International -     

Effect of feeding regime and temperature on ongrowing results of pikeperch (Sander lucioperca L.)

This study aimed to determine the effect of feeding rates and water temperatures on the growth, feed utilization and size heterogeneity changes in subadult pikeperch. Fish with an average weight of 84±19 g were fed with a commercial trout diet for 18 weeks at a water temperature of 20 °C and 25 °C. Four feeding rates (PSFR) were predicted at both temperatures, which corresponded to 1.0%, 1.25%, 1.50% and 2.0% of body weight per day (bw day⁻¹) for the first, and to 0.8%, 1.0%, 1.2% and 1.4% of bw day⁻¹ for the second 9 weeks respectively. At the end of the experiment, the individual weight averaged 273±82 g. Pikeperch showed a better growth rate [specific growth rate (SGR)] and apparent feed conversion rates (AFCR) at the higher temperature. Thermal-unit growth coefficient (TGC) was better at the lower temperature. The values of SGR, TGC and AFCR significantly increased with increasing PSFR at both temperatures. The values of TGC plotted against the computed feeding rates allowed estimation of the maximum feeding rates (1.25% and 1.15% of bw day⁻¹ for pikeperch of 150–180 g at 25 and 20 °C respectively). Size heterogeneity changes were affected neither by the feeding rate nor by temperature.     

Hormonal induction of ovulation in pikeperch (Sander lucioperca L.) using human chorionic gonadotropin (hCG) and mammalian GnRH analogue

The aim of the present study was to study spawning stimulation in artificial reproduction of females pikeperch (Sander lucioperca L.) using “Chorulon” containing the human chorionic gonadotropin (hCG) and compare with “Supergestran” containing a mammalian GnRH ([D-Ala⁶]GnRHProNhet) analogue. The females were divided into eleven experimental groups and injected with hCG at 250, 500, 750, and 1 000 IU kg^?1 body weight (BW) and mGnRHa at 1, 2.5, 5, 10, 25, and 50 μg kg^?1 BW. In all treatments, a single intramuscular injection of hormone was performed. Control group was injected with 0.9 % NaCl, 0.9 cm³ kg^?1 BW. The average percentages of ovulating females were 88.5 ± 12.3 and 80.8 ± 10.9 % in hCG- and mGnRHa-treated groups, respectively. The average diameter of eggs was 0.95 ± 0.06 and 0.98 ± 0.06 mm in hCG- and mGnRHa-treated groups, respectively. Neither ovulation rate nor diameter of egg was statistically differed among hormonally treated groups. Statistical difference was observed only in hatching rate, where the average were 73.6 ± 14.4 and 50.6 ± 17.7 % in hCG and mGnRHa-treated groups, respectively. Among hormonally treated groups, the best results were observed in groups treated with hCG at 500 and 750 IU kg^?1 and in groups treated with mGnRHa at 25 μg kg^?1. No ovulation was observed in the control group. This study indicated successful ovulation in pikeperch using a single intramuscular injection of hCG or mGnRHa analogue.     

Effects of hormonal manipulation on stress responses in male and female broodstocks of pikeperch Sander lucioperca

This study was designed to determine the effects of hormonal manipulation on stress responses in female and male pikeperch. Two-year-old cultured female and male broodstocks with an average weight of 337.4 ± 20.1 (mean ± SE; n = 16) and 318.7 ± 15.1 g (n = 16), respectively, were randomly allocated into four hormonal treatments each containing 4 fish. Two sexual groups of 16 fish for each gender were considered. Sexually mature male and female pikeperch were injected with either physiological saline solution (as control group), common carp pituitary extract (CPE), human chorionic gonadotropin (hCG) and or luteinizing hormone-releasing hormone analog (LHRHa₂). The blood samples were taken before hormonal injection and after ovulation and spermiation. Then the plasma levels of stress indices (cortisol, glucose, and lactate) were determined. The results showed that all CPE-, HCG-, and LHRHa_2- injected males produced sperm. In females treated with CPE and hCG, three of four ovulated, but none of LHRHa_2- and saline-injected fish spawned. Significant changes in cortisol, glucose, and lactate levels were observed among the females injected with different hormones. Plasma cortisol and glucose levels increased significantly in males injected with CPE and females injected with hCG, but no significant change was observed in lactate levels before and after hormonal induction. Comparison of two sexes revealed significant differences in glucose levels for females in some groups before injection, while CPE-injected sexes showed significant changes in cortisol and lactate concentrations. The results indicated that the induction of ovulation or spermiation stimulated stress responses especially in female pikeperch, and therefore, all the procedures should be made to minimize the disturbance during the artificial spawning.     

Induced out-of-season and seasonal tank spawning and stripping of pike perch (Sander lucioperca L.)

Nine trials were carried out on the induced propagation of pike perch in out‐of‐season as well as in the natural reproduction period. From January till May, periodically, 16–20 pairs were transported to the hatchery, and acclimated to 15–16°C. The following hormonal treatments were used to induce reproduction: carp pituitary homogenate (CP) and human chorionic gonadotropin (hCG) alone or in combination; gonadotrop‐releasing hormone ‘Ovurelin’ (D‐Phe⁶‐LH‐RH) alone or with metaclopramid (MTC); and ‘Ovopel’ [containing des‐Gly¹⁰‐(D‐Ala⁶)‐LH‐RH‐ethylamide and MTC]. The effects of daylight regime, water temperature and the length of the pre‐spawning conditioning period on the reproduction performance were determined. From the 130 hormonally treated pairs, 122 either spawned in tanks or were stripped. There were no differences in the ovulation rate between out‐of‐season (93%) and seasonal (91%) propagation. The developmental stage of the eggs correlated with the latency period, which significantly declined from January till April. The latency period was the shortest in fish treated with hCG and, secondly, with CP. The germinal vesicle migration did not proceed without hormonal treatment, although in some trials breeders were kept at the spawning temperature for 1–2 weeks. The results demonstrate that the pike perch can be successfully induced to spawn about 3 months earlier than its natural spawning season, which allows a significantly prolonged yearly supply of fry.     

Movements and habitat use by pikeperch (Stizostedion lucioperca (L.)) in a hydropeaking reservoir

Abstract –  We used radio telemetry to measure the habitat use and movements of 20 tagged pikeperch (44–59 cm) in the hydropeaking Pyhäkoski Reservoir, Finland, during June 1999–2000. The hydrological conditions in the 8-km-long reservoir were measured and then modeled over eight discharge rates between 30 and 700 m³ · s⁻¹. Pikeperch preferred relatively low water velocities and deep water depths especially during the winter. During the summer, pikeperch moved actively in different parts of the reservoir. No relationship was found between hydroelectric plant operations and distances moved by pikeperch during the summer. Movements peaked in autumn but decreased during the winter to a restricted area. After 1 year of monitoring, 4 out of 20 tagged pikeperch remained in the Pyhäkoski Reservoir, three had died when descending from hydroelectric dams, 10 had descended downstream to other reservoirs or sea, two were captured by local fishermen, and one fish's signal was lost for unknown reasons.     

The effect of fish size and stocking density on the weaning success of pond-cultured pikeperch Sander lucioperca L. juveniles

The effect of initial fish size (small with TL = 40.3 ± 2.3 mm and W = 0.42 ± 0.15 g, medium with TL = 56.2 ± 2.7 mm and W = 1.66 ± 0.4 g, and big with TL = 71.0 ± 3.2 mm and W = 2.95 ± 0.65 g) and stocking density of identical fish with TL = 40.3 ± 2.3 mm and W = 0.42 ± 0.15 g (1; 2; 4; 8 fish l^?1) on weaning success was evaluated in pond-cultured pikeperch. The trial was divided into weaning (12 days) and post-weaning (16 days) periods. Small juveniles reached significantly higher specific growth rate (SGR = 1.6 ± 0.2 % day^?1) and survival rate (S = 81.7 ± 2.7 %) and lower cannibalism (C = 3.0 ± 0.75 %) compared to medium and large juveniles (SGR = 0.3–0.5 % day^?1, S = 65.3–76.5 %, C = 6.5–7.5 %) during the weaning period. The higher survival rate was found at the two higher densities (S = 72.0–79.1 %) during the weaning period. The lowest survival rate (S = 38.9 ± 2.7) was observed at the lowest fish density. Fish stocking density did not affect growth, condition, or cannibalism rate during the weaning period. Similar trends of growth, survival, and cannibalism of weaned juveniles were observed during the post-weaning period. A mass weaning trial verified experimental results showing small pikeperch juveniles to reach satisfactory growth rate (SGR = 1.4 ± 0.1 and 7.2 ± 0.2 % day^?1), survival (S = 78.7 ± 3.0 % and 97.6 ± 1.0 %), and cannibalism (C = 4.0 ± 1.5 % and 2.5 ± 1.0 %) rates during the weaning and post-weaning periods. No body or fin deformities of weaned juveniles were observed.     

Effect of different commercial spawning agents and thermal regime on the effectiveness of pikeperch, Sander lucioperca (L.), reproduction under controlled conditions

Pikeperch, Sander lucioperca (L.), has been identified as one of the most perspective candidates for diversification of freshwater aquaculture. However, some aspects of production are still being developed, and controlled reproduction is one of the bottlenecks. The aim of the present study was to compare the effectiveness of different commercial spawning agents in the induction of final oocyte maturation (FOM) and ovulation in wild spawners. Within the study, four spawning agents [human chorionic gonadotropin (hCG), mixed human and horse gonadotropin (PG-600), carp pituitary (CPH) and mammalian GnRH analogue combined with metoclopramide (Ovopel)] in different thermal regimes (13 and 15 °C) were tested. In both thermal regimes, the highest (P < 0.05) ovulation rate among the treatment groups was obtained after stimulation with hCG (100 % in both cases). Latency time was the shortest in groups where CPH was used (2–3 and 3–4 days for 15 and 13 °C) and was similar in the remaining groups (3–4 and 4–5 days for 15 and 13 °C, respectively). Embryo survival was the highest in groups treated with hCG (78.9 and 81.3 % at hatching stage for 15 and 13 °C, respectively). Hormonal stimulation did not significantly affect spermiation rate or spermatozoa motility (P > 0.05). Based on the obtained results, hCG can be recommended for induction of FOM and ovulation in pikeperch. In addition, the thermal regime within the tested range seemed to have no effect on the reproduction outcome, and the application of lower temperature only prolonged the time of ovulation.     

Effect of different dietary fat content and fat type on the growth and body composition of intensively reared pikeperch Sander lucioperca (L.)

Two, 42‐day feeding experiments were carried out in aquaria working in a recirculation system, to determine the influence of the different dietary fat levels and fat sources on the growth and body composition of pikeperch fingerlings. In the first experiment three levels of dietary fat (F0: 60; F1: 120; F2: 180 g kg^?1) were tested, compared with a commercial diet (Trouvit, 240 g kg^?1 fat content). F1 and F2 were formulated by adding fish oil. Best growing and feed conversion ratio was obtained with the commercial control diet, which produced also the highest total body fat (117 g kg^?1) while respective values of fish fed on the other three diets varied between 74.1 and 85.1 g kg^?1. Different feeds had no significant differences in crude protein content of the fish body. In the second test, besides feeds F0, F1 and F2, two additional feeds were formulated containing 127 g kg^?1 (L1) and 178 g kg^?1 (L2) crude fat (from linseed oil). Dietary fat levels and fat sources had significant effect neither on growth nor on feed conversion ratio. Chemical composition of the whole body did not change significantly due to the different feeds. Linseed oil had a decreasing effect on the sum of saturated fatty acids and increased the oleic and the α‐linoleic acid proportions in fillet. However, total polyunsaturated fatty acid (PUFA) proportion remained constant.     

Alcalase treatment for elimination of stickiness in pikeperch (Sander lucioperca L.) eggs under controlled conditions

Elimination of egg stickiness is an important factor in artificial reproduction of pikeperch (Sander lucioperca L.). This study was conducted to evaluate the effectiveness of Alcalase enzyme to remove the adhesive layer of pikeperch eggs. The eggs were treated with Alcalase at 0.5, 1.0, 1.5, 2.0 and 5.0 mL L^?1 or a milk/talc solution 2 min post insemination. Duration of exposure was 2 min in Alcalase and 60 min in milk/talc. The highest, albeit not significant, hatching rate (85.4%) was found with 1.5 mL L^?1 of Alcalase, but hatching rates were similar in 0.5, 1.0 and 2.0 mL L^?1. Hatching rates were significantly lower groups treated with 5.0 mL L^?1 Alcalase enzyme (56.4%) compared to groups treated with milk powder and talc (61.3%). Nominally complete removal of adhesiveness was observed in 1.5 and 2 mL L^?1. All Alcalase treatments led to significantly lower incubation duration compared with the traditional milk/talc treatment. The application of Alcalase successfully eliminated pikeperch egg stickiness in less time than with traditional milk/clay/talc methods.     

Growth in juvenile pikeperch (Sander lucioperca L.) stimulated with yeast,Saccharomyces cerevisiae,extract

Thanks to the content of valuable bioactive substances, yeast, Saccharomyces cerevisiae, is finding wider applications in aquaculture and marine fish husbandry. Highly bio‐available and bio‐assimilable yeast extracts, which are obtained through processes that remove cell walls, are of special interest. The current study examined the impact of yeast extracts added to commercial feed at concentrations of 2% (group F2), 4% (group F4) and 6% (group F6) on growth, blood biochemistry parameters, liver and intestinal morphology, proximate body composition and the content of free amino acids in the muscle tissues of European pikeperch, Sander lucioperca (initial body weight = 10 g). At the termination of the experiment that ran for 60 days, the highest increases in body weight were noted in all the groups of fish that had received yeast extract (final body weight ≈ 35 g vs. control group ≈ 31 g). The daily and specific growth rates indexes were the highest in group F6. The alanine aminotransferase activity in this group was half of that in the control group (group C) (p < .05). The lowest levels of plasma bilirubin were noted in groups F4 and F6, while these groups had the highest hepatosomatic indexes that differed significantly to those of group C (p < .05). Microscopic analysis of the intestines indicated significant growth in the enterocyte height and supranuclear zone, or the so‐called absorption space, as the quantity of yeast extract added to the diets increased. Yeast supplementation was not noted to have a significant impact on the proximate body composition or the contents of free amino acids in the fish muscle tissues. In conclusion, the lowest analysed dose of yeast (i.e. 2% yeast extract) stimulates the growth of pikeperch.     

Effect of different sources and levels of dietary phospholipids on performances and fatty acid composition of pikeperch (Sander lucioperca) larvae

The aim of this study was to evaluate the effects of dietary phospholipids (PL) sources (fish gonad G‐PL and soybean lecithin S‐PL) and levels (50 and 90 g kg^?1 dry matter) on the performances and fatty acid (FA) composition of pikeperch larvae. From day 10 to day 34 posthatching (p.h.), larvae were fed with three isoproteic and isolipidic microdiets. The best results of growth and skeletal development were related to a high phospholipid level regardless of their origin and FA profile. Jaw deformities seemed associated with high dietary highly unsaturated FA (HUFA) level. The optimal level of eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA) for pikeperch larvae appeared to be around 12 g kg^?1 (dry matter) associated with a PL level around 90 g kg^?1. FA composition of diets and larvae revealed a better incorporation of arachidonic acid, EPA and DHA into PL fraction especially in larvae fed with soybean PL. Moreover, 34‐day‐old pikeperch larvae may have capability of converting 18 carbon n‐3 FA into the n‐3 HUFA. Hence, for pikeperch larvae, PL from plant origin were as efficient as those from marine fish origin.     

Effects of turbidity on feeding of the young-of-the-year pikeperch (Sander lucioperca) in fishponds

The effect of water turbidity on the prey selection and consumption of the young-of-the-year (YOY) pikeperch in the planktivorous feeding stage was studied. Attention was paid particularly to the question of how the food selectivity depends on the size of YOY pikeperch and how the turbidity affects feeding in different size classes. Studies were carried out in ponds of two fish farms in Estonia over 4 years. Small cladocerans were the most preferred prey in the smallest pikeperch size class. In larger size classes, the most selected prey were the large cladocerans. Water turbidity affected the prey selection of the planktivorous pikeperch significantly. In more turbid environments, the larger zooplankters were more positively selected than the smaller ones. Turbidity decreased both total zooplankton consumption and Fulton's condition factor of fish only in the largest size class of pikeperch. The effect of turbidity on foraging and growth, and thus on the size of juvenile pikeperch of a particular year class is substantial under conditions where juveniles cannot shift from planktivory to piscivory.     

Out-of-season spawning of pike perch (Sander lucioperca L.) without the need for hormonal treatments

The provision of fry and fingerlings, independent of the natural spawning season, can facilitate the implementation of innovative rearing strategies also in pike perch ( Sander lucioperca L.). As strict pharmaceutical acts or codes of conduct for organic aquaculture can constrain fish farmers in inducing spawning with hormonal applications, this study intended to develop protocols for advanced and postponed spawning just by simple photo-thermal treatments. After spending between 31 and 61 days at temperatures below 10 °C, different groups of pike perch spawners were treated with light and temperature programmes to advance spawning. Reproduction could be induced successfully 2 months before the natural spawning season when the mating pairs spent 43 or more days below 10 °C, followed by a maturation phase of 44–68 days at 15 °C and 16 h illumination per day. Advanced spawning could be documented for 32 out of 35 females (91%) that underwent photo-thermal treatments. Mean commercial fecundities up to 24% and average rates of developing eggs of 65% were observed in advanced spawning groups. Coldbanking of mature females allowed to postpone spawnings for 2 and 3 months. However, no egg development could be recorded in these treatment groups.     

Effects of brewer’s yeast extract on growth performance and health of juvenile pikeperch Sander lucioperca (L.)

Juvenile European pikeperch, Sander lucioperca, were fed commercial feed (group C) or experimental feed supplemented with NuPro^® nucleotide‐rich Saccharomyces cerevisiae yeast protein (extract obtained through a cell wall removal process) in doses of 20, 40 or 60 g kg^?1 feed (groups N2, N4, N6) for 8 weeks. Growth, non‐specific immunity parameters, histological structure of the liver and intestine, proximate whole‐body composition and blood biochemical parameters were assayed. It was noted that brewer’s yeast extract has immunomodulatory proprieties. NuPro^® in doses of 40 and 60 g kg^?1 feed strongly stimulated non‐specific (innate) cellular and humoral immunity in pikeperch. The experimental feed did not have a significant impact on pikeperch growth (P > 0.05). The proximate composition of the fish bodies and the hepatosomatic and viscerosomatic (VSI) indices were also not affected, which indicated that the tested diets had no negative impact on the metabolism or deposition of nutrients in fish tissues. The lower levels of transaminases AST and ALT, which were noted in the groups with the two highest doses of NuPro^® (P < 0.05), might indicate improved liver function. It was also demonstrated that the brewer’s yeast extract stimulates the absorption activity of intestinal epithelial cells.