TECHNOLOGY FOR ARTIFICIAL SPAWNING OF SILURUS GLANIS SPECIES – WELLS TECHNOLOGY DISPLAY TECHNOLOGY DISPLAY Object Object The elaborated technology is after controlled spawning of Silurus glanis – wells, towards redressing its natural populations and inserting it on aquaculture. The elaborated technology is after controlled spawning of Silurus glanis – wells, towards redressing its natural populations and inserting it on aquaculture. Area of implementation Area of implementation Implicit costumers of spawning technology are economical agents that have the main activity fishing and aquaculture. Implicit costumers of spawning technology are economical agents that have the main activity fishing and aquaculture.

Technological system for artificial spawning of Silurus glanis – wells Technological system for artificial spawning of Silurus glanis – wells For artificial spawning of wells having regard to special reproductive features of species, must ensure a technical-material base specific and in accordance with different stages of this process. For artificial spawning of wells having regard to special reproductive features of species, must ensure a technical-material base specific and in accordance with different stages of this process. Technological system will be apportion depending on production capacity agreed by costumer, and will ensure by its capacity the spawning of minimum 10 families, in order to insure maintenance and conservation of genetic biodiversity of species. Technological system will be apportion depending on production capacity agreed by costumer, and will ensure by its capacity the spawning of minimum 10 families, in order to insure maintenance and conservation of genetic biodiversity of species. Correlate with the capacity for incubation, technological system will be framed by an ensemble of earthen ponds: ponds for standing- wintering, ponds for pre-maturation, modules for standing and maturation of breeders, modules for incubation of embrionated eggs and modules for standing and growing larvae. Correlate with the capacity for incubation, technological system will be framed by an ensemble of earthen ponds: ponds for standing- wintering, ponds for pre-maturation, modules for standing and maturation of breeders, modules for incubation of embrionated eggs and modules for standing and growing larvae.

Ponds for pre-maturation, modules for maturation of breeders and modules for incubation of eggs have the same properties as the case of pikeperch. Ponds for pre-maturation, modules for maturation of breeders and modules for incubation of eggs have the same properties as the case of pikeperch. For standing and rearing larvae should be used PVC or fiberglass tanks with volume of about 1300 l, fitted with proper fuel system, adjustment and discharge of water. For standing and rearing larvae should be used PVC or fiberglass tanks with volume of about 1300 l, fitted with proper fuel system, adjustment and discharge of water.

DESCRIPTION OF TECHNOLOGY Technology for artificial spawning and rearing larvae of Silurus glanis involves travel along following stages: Technology for artificial spawning and rearing larvae of Silurus glanis involves travel along following stages: Assurance of breeders stock; Assurance of breeders stock; Evaluation of phenotypic characters and sex determination; Evaluation of phenotypic characters and sex determination; Standing, pre-maturation of breeders; Standing, pre-maturation of breeders; Maturation of breeders; Maturation of breeders; Induction of sexual cells maturation; Induction of sexual cells maturation; Gathering sexual products; Gathering sexual products; Fecundation; Fecundation; Incubation of sexual products in special installed enclosures; Incubation of sexual products in special installed enclosures; Sampling and standing larvae in enclosure standings; Sampling and standing larvae in enclosure standings; Sacking and transportation of larvae; Sacking and transportation of larvae; Rearing larvae up to 45 days. Rearing larvae up to 45 days.

Assurance of breeders stock. Assurance of breeders stock. Wells breeders used in artificial spawning come from stocks reared in farms especially for this goal. Wells breeders used in artificial spawning come from stocks reared in farms especially for this goal. For the establishment of breeders stock are chosen fish with age of 4 – 8 years and weight of 6 – 10 kg. For the establishment of breeders stock are chosen fish with age of 4 – 8 years and weight of 6 – 10 kg.

Morphological criteria used to determine sex on wells Criteria/sex MaleFemale Form of genital papilla Concave, smallBulging, ovoid Head formSlightly foursquare shape Foursquare Roughness of pectoral fins Earthy Light color The color of tegument in the ventral area DarkSmooth touch Sedimentation of erythrocytes SlowFast

Hormonal treatment goes through after 24 hours from stocking of breeders in the station for incubation. For induction of sexual cells maturation on wells, it is used carp pituitary. Hormonal treatment goes through after 24 hours from stocking of breeders in the station for incubation. For induction of sexual cells maturation on wells, it is used carp pituitary. Hormonal induction of females is made in two steps: Hormonal induction of females is made in two steps: Step I – 0.5 mg/kg of body weight for both females and males; Step I – 0.5 mg/kg of body weight for both females and males; Step II – 4 mg/kg of female body weight and 3 mg/kg of male body weight. Step II – 4 mg/kg of female body weight and 3 mg/kg of male body weight. Before injection and gathering gametes breeders are anesthetized in a solution of 2-fenoxietanol (1 : 1000). Before injection and gathering gametes breeders are anesthetized in a solution of 2-fenoxietanol (1 : 1000).

Gathering eggs and artificial fertilization. Method of harvesting is abdominal palpation, technology known as “milking”. Gathering eggs and artificial fertilization. Method of harvesting is abdominal palpation, technology known as “milking”. Abdomen is gently massaged on longitudinal direction up and down, along axial line of abdomen, pushing eggs by the genital hole. Abdomen is gently massaged on longitudinal direction up and down, along axial line of abdomen, pushing eggs by the genital hole. From each female collect a single portion of eggs, about 160 – eggs. From each female collect a single portion of eggs, about 160 – eggs. Sperm is gathered in a crystallizer by abdominal palpation or by using a syringe with tygon tube of 5-6 cm long. Sperm is stored for 4 hours at 4 0C. Volumetrically, average quantity of sperm gather is 2.0 – 2.5 ml/kg of body weight. Males generate between 0.13 – 0.14 × 109 spermatozoids/kg body weights. Sperm is gathered in a crystallizer by abdominal palpation or by using a syringe with tygon tube of 5-6 cm long. Sperm is stored for 4 hours at 4 0C. Volumetrically, average quantity of sperm gather is 2.0 – 2.5 ml/kg of body weight. Males generate between 0.13 – 0.14 × 109 spermatozoids/kg body weights. Artificial fertilization Artificial fertilization Fertilization is accomplished with mixture of sperm originating from at list 2 – 3 males. For fertilization of 100 g of eggs are required 2 ml of sperm. Fertilization is accomplished with mixture of sperm originating from at list 2 – 3 males. For fertilization of 100 g of eggs are required 2 ml of sperm. Eggs and sperm are mixed in a fertilizing solution made by 0.3 % NaCl. The volume of activating solution is 50 ml/100 g of eggs. Mixture is homogenized for 10 seconds, and then, after 2 minutes add another 25 ml of activating solution and eggs are spread on nytal frames with help of a feather. After another 5 minutes, fertilized eggs are bringing in Nucet hatcheries for incubation. Eggs and sperm are mixed in a fertilizing solution made by 0.3 % NaCl. The volume of activating solution is 50 ml/100 g of eggs. Mixture is homogenized for 10 seconds, and then, after 2 minutes add another 25 ml of activating solution and eggs are spread on nytal frames with help of a feather. After another 5 minutes, fertilized eggs are bringing in Nucet hatcheries for incubation.

Sampling and standing larvae Sampling and standing larvae Sampling of hatched larvae is made continuously on cushion of water, in individual tanks for gathering. Gathering tank is fitted with a nytal cage having mesh size of 0.3 – 0.5 mm to constrict the larvae. Sampling of hatched larvae is made continuously on cushion of water, in individual tanks for gathering. Gathering tank is fitted with a nytal cage having mesh size of 0.3 – 0.5 mm to constrict the larvae. The constricted larvae are sample with the help of paddles and placed in special enclosure for standing. The operation is carried out continuously until the end of hatching. Counting larvae is accomplished directly at the time collection. The constricted larvae are sample with the help of paddles and placed in special enclosure for standing. The operation is carried out continuously until the end of hatching. Counting larvae is accomplished directly at the time collection. Stocking density will be of 40 – 60 ex/l. flow of water in standing tanks will be adjusted to 5 l/min. Larvae will stay on these enclosures a period of 5 – 7 days up to resorption of yolk. Stocking density will be of 40 – 60 ex/l. flow of water in standing tanks will be adjusted to 5 l/min. Larvae will stay on these enclosures a period of 5 – 7 days up to resorption of yolk.

Growth of larvae up on achieving adult-like phenotypic characters Growth of larvae up on achieving adult-like phenotypic characters Stocking rate Stocking rate Larvae achieved from each female are stoked independently on rearing enclosures. Larvae achieved from each female are stoked independently on rearing enclosures. Stocking rate is 1500 ex/m3 and is determined taking into account technological losses for rearing phase which in general are estimated on 30 %. Stocking rate is 1500 ex/m3 and is determined taking into account technological losses for rearing phase which in general are estimated on 30 %. The height of water column in rearing enclosures is adjusted to 20 cm. The height of water column in rearing enclosures is adjusted to 20 cm. Technological water from enclosures will be assessing physic-chemically by determination of temperature, pH and oxygen. Technological water from enclosures will be assessing physic-chemically by determination of temperature, pH and oxygen. The flow of water supply in enclosures for pre- maturation is set at 5 – 7 l/min. The flow of water supply in enclosures for pre- maturation is set at 5 – 7 l/min.

Feeding Feeding Rearing of larvae up to outlining phenotypic characters conformable with adults is achieved on account of a feeding schedule involving deliver of live food and blended yolk of egg in first 5 – 7 days of growth and then a composite diet composed of natural food and forage. Rearing of larvae up to outlining phenotypic characters conformable with adults is achieved on account of a feeding schedule involving deliver of live food and blended yolk of egg in first 5 – 7 days of growth and then a composite diet composed of natural food and forage. Feeding with natural food is achieved with very small zooplankton. The diet is supply with blended yolk of egg. Feeding with natural food is achieved with very small zooplankton. The diet is supply with blended yolk of egg. Feeding of larvae using natural live food in a composite diet with forage will imply the use of following feeding schedule that will allow gradually passing to a feeding based exclusively on forage: Feeding of larvae using natural live food in a composite diet with forage will imply the use of following feeding schedule that will allow gradually passing to a feeding based exclusively on forage: first 5 days: 85 % zooplankton, 15 % forage; first 5 days: 85 % zooplankton, 15 % forage; next 5 days: 60 % zooplankton, 40 % forage; next 5 days: 60 % zooplankton, 40 % forage; next 5 days: 50 % zooplankton, 50 % forage; next 5 days: 50 % zooplankton, 50 % forage; next 5 days: 10 % zooplankton, 90 % forage. next 5 days: 10 % zooplankton, 90 % forage. After that feeding will be assure only by forage. After that feeding will be assure only by forage. With the passage exclusively on forage, daily ration will be determined depending on consumption, percentage ranging from 4 to 20 % of batch weight. With the passage exclusively on forage, daily ration will be determined depending on consumption, percentage ranging from 4 to 20 % of batch weight. During rearing time preventive treatments are made for mix bacteria and ichtyophtiriosis; these disease are symptoms: abatement, bleaching tail with necrosis and then fall of necrosis part of the tail. For treatment use oxytetracycline + neomycin. During rearing time preventive treatments are made for mix bacteria and ichtyophtiriosis; these disease are symptoms: abatement, bleaching tail with necrosis and then fall of necrosis part of the tail. For treatment use oxytetracycline + neomycin. For ichtyophtiriosis use malachite green combined with formalin. For ichtyophtiriosis use malachite green combined with formalin.