Artificial Reproduction of sturgeon fishes in Romania and Moldova

Materials of this site with last changes, additions and new materials are made out in 5 articles which are published in April, 2005 in the collected articles of an anniversary international scientific-practical conference "VNIIRs". (" Aquiculture and integrated technologies: problems and opportunities", vol. 2, Moscow, 2005). Here these materials are given for express-acquaintance of the experts-fish-breeders. To reserve collections of a conference "VNIIRs" it is possible on e-mail: LfB@flexuser.ru.
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ARTIFICIAL REPRODUCTION OF STURGEON FISHES IN ROMANIA AND MOLDOVA.

Vedrashko A.I.

Works on artificial reproduction of sturgeon fishes in Moldova are started in 1979 from creation of repair-mothering herd sterlets from river Dniester and further are continued with use repair-mothering herds the Lensky sturgeon and paddle-fish. Application accessible during this period acetonised hypophysises of sturgeon fishes at reproduction of a sterlet, the Lensky sturgeon and paddle-fish caused maturing of females at a level 65–70%. Further works on reproduction sturgeon in Moldova have been stopped because of partial destruction repair-mothering herds, experimental base (during time the “Pridnestrovsky” conflict) and absence of an opportunity of purchase of hypophysises of sturgeon fishes. Renewal of artificial reproduction sturgeon is started in 1995 from skilled works on testing preparation Nerestin-5(5А, 5B) on manufacturers paddle-fish, kept in Moldova in ponds of joint-stock company “Kosteshty” and fish farm “Ivancha”, and also in Romania on wild manufacturers stellat sturgeon, the Russian sturgeon and beluga, caught in Danube in conditions experimental bases “Bratesh Mik” and a private reproductive complex sturgeon firms “Caviar House”, and on paddle-fish - in research piscicultural stations “Nuchet”. For the first time preparation Nerestin-5 has been tested on sturgeon fishes in Russia simultaneously with Nerestin -1 on plant-feeding fishes and a carp in 1989, however these works on sturgeon, despite of positive results, in view of absence of external financing had no regular character. Term “Nerestin” (from Russian word “нерест” - spawning) is entered into the reference by one of first employees SPC “Aquaculture” nowadays Dr.Sci.Biol. of ITEB, the Russian Academy of Science, Stanislav Kolesnikov.

The repair-mothering herd of paddle-fish (Polyodon spathula, group Acipenseriformes, the family Polyodontidae) is submitted to station “Nuchet” five senior age groups of the fishes that have been brought up in local ponds from larvae, received from wild manufacturers in the USA. For work on reproduction of paddle-fish it has been lead valuation of eight, nine - and ten-years fishes, are selected females and males. At females such pisciculturally-biological parameters, as general length - L, length up to the basis of a tail fin - l, the maximal grasp - O, of fatness - Ff and a condition of sexual products on factor of polarization of a nucleus of oocytes - Fpn were defined.

Table 1. PISCICULTURALLY-BIOLOGICAL CHARACTERIZATION OF PADDLE-FISH FEMALES

At paddle-fish males the degree of display of “the marriage order” also was estimated: “+” - the marriage order only on a head, “+ +” - the marriage order on a head and a back, “+ + +” - the marriage order covers all body of a fish, “+ + + +” - the marriage order covers all body of a fish, the genital aperture is slightly inflamed (table 2).

Таблица 2. PISCICULTURALLY-BIOLOGICAL CHARACTERIZATION OF PADDLE-FISH MALES

All manufacturers of fishes were firstly-spawninged. As have shown resulted in tables 1 both 2 results of valuation and measurements, males and females of paddle fish were in a good physiological condition with 4 stage maturity of sexual products that allowed to carry out experiments with use of preparation Nerestin. At males with an estimation of a degree of display of the marriage order “+” and “++” quality of sperm is estimated in 2-3 points on a 5-ball scale and maturing occurs later; therefore such males undertook in experience only as an insurance reserve.

At approach of spawning temperatures (12⁰-14⁰ С) manufacturers of paddle-fish replaced in prespawning pools separately on sexes. Injections of females carried out preparations Nerestin-5 and Nerestin-5А in 2 stages: a preliminary injection at 20.00 - 22.00 o'clock in the evening in quantity 20% from the total doze, an allowing injection in 12 hour at 8.00 - 10.00 o'clock in the morning in volume 80% from the general doze. Males have been injected unitary direct after preliminary introduction of a preparation to females in volume 50% from the total doze of a preparation for females.

General doze Nerestin-5 for paddle-fish females precisely corresponded to marks on bottles in capacity of 20 ml and has made 0,4 ml/kg of weight of a fish, and Nerestin-5А – 0,2 ml/kg; or for females in weight, for example, 8 kg – 3,2 ml (0,64+2,56 ml) and 1,6 ml (0,32+1,28 ml) on a fish, accordingly. Some of bottles of a preparation for date of application already had expired 2 years working life, but appreciable decrease in activity of preparations has not been revealed. For males and females with more expressed attributes of readiness for reproduction (on set of parameters of tables 1 and 2) entered dozes of preparations reduced on 4–8% from recommended. Small volumes of a preparation entered an insulin-syringe or precisely graduated syringe in volume of 2,0 ml intramuscularly on depth of 1,5 cm into back area of fishes on removal 10-15 cm from a head and with an inclination of a needle in its party. A place of an injection pressed down a finger and massed for prevention escaping a preparation outside and acceleration of his receipt in a blood-groove. Inflammations at fishes in a place of an injection and any collateral reactions it was not observed, the behavior of fishes was quiet. Action of preparations Nerestin-5 and Nerestin-5А was soft and differences between them consist only in volume of introduction.

Everything specified in tab. 1 and 2, females and males of paddle-fish have answered positively on Nerestin-5(5А) ovulation and spermiation. At females spawn has been ovulated through 24-28 hour after the second injection. Fertilisation of spawn from everyone female made sperm from 2-3 males. As sperm received by a method of syringed-suction, the final volume sperm was not measured, but visually his quality and quantity were in norm. Ovulated oocytes received in one's lifetime by straining off after incision of ovum-conductions on the method of S.B.Podushka.

The survival rate males and females of paddle-fish after the made injections and operations has made 100%. Average working fruitfulness 9-year-old females was equaled 120000 pieces of spawn, 10-year-old - 148000. The average percent of fertilisation of spawn has made 84%, percent hatching of larvae–76%, survival rate of business larvae at their average weight 8-10 mg – 93%. Incubation of spawn it was carried out in the device such as the “Sterlet”, developed by SIFFS of Kishinev in 1992. Hatching of larvae at temperature 13-14⁰ С was occurred on 5-7 days. Deformities and anomalies of development of larvae it is not marked.

Translation paddle-fish larvae on the mixed active feed and rearing of young fishes up to average weight 340 mg during 21-22 days made on natural forages (zooplankton) in concrete pools at initial density of landing of 80000 pieces/m³. The survival rate of rearing young fishes from total business larvae has made 86,5%.

In total for the period 2001–2004 in Romania and Moldova for artificial reproduction have been injected by Nerestin-5 (5А) 86 females of paddle-fish from which have positively answered a preparation 81 pieces, i.e. 94,1%. Besides employee of Kishinev SIFFS P.D.Arikov (the personal message) in 2002 in Moldova has been injected by Nerestin-5А 12-year-old paddle-fish, 4 females in average weight 12 kg and 3 males on 8,5 kg. At temperature of water 11,5-14,0 ⁰С and the scheme of injections, described above, he receives full maturing all manufacturers (females - on the average in 47 hours after the first injection) with straining off on the average on 1,2 kg of spawn from females, at percent of fertilisation of spawn – 85%, quantity hatching of larvae under the attitude to all spawn – 57%, survival rate of larvae in 5 day – 75%.

For artificial reproduction of stellate sturgeon (Acipenser stellatus) from river Danube for the period of 1995-2004 38 females in average weight 6,4 kg (4,5-9,8 kg) and 51 males in average weight 5,5 kg have been used. Catching of wild manufacturers of sturgeon fishes was carried out by the enterprises of Romania "Bratesh Mik " (experimental base of the Center on fish culture, fishery and processing of a fish, Galatz) and "Caviar House " (private enterprise) within the limits of the quotas allocated by the state. Fishes have transferred stress of catching and transportation, the part from them had external traumas.

Ovulated оocytes from females and sperm from males of stellate sturgeon received with use of preparations Nerestin-5 in the total doze of 0,4 ml/kg and Nerestin-5А (0,2 ml/kg) at temperature of water 22-24 ⁰С. Fishes injected intramuscularly at a level of the third back “zhuchka” a syringe in capacity of 2,0 ml on depth 1,5 cm. Preparations for females gave fractionally (20% + 80%) with an interval 12 hours, for males gave 50% from the total doze for females simultaneously with a preliminary injection. Males ripened earlier of females, sperm received by a method of syringed-suction in 12-18 hours after injections and stored in a refrigerator. Possible decrease in a doze for males up to 1/3 from a doze for females yet did not apply. Females ripened in 24-28 hours after the second injection and spawn from them took in one’s lifetime straining off after incision of ovum-conductions. On the average 72% wild caught from Danube stressed manufacturers of stellate sturgeon have positively answered preparations by ovulation and spermiation (basically the fishes having traumas “have not answered”), from them 85% females and 62% of males. In catch got males, already participating in natural spawning in Danube, they, apparently, also have not reacted to a preparation. The survival rate of fishes after the lead operations has made 83% (died wounded and it is strong stressed), percent of fertilisation of spawn – 81%, quantity of hatching larvae – 76%. Working fruitfulness of stellat sturgeon females was up to standard 100 - of 150 thousand pieces spawn, volume taken by a syringe sperm at males - on 10 ml.

Spawn of every female was impregnated by sperm of 2-3 males. Incubation spawn carried out at t = 23 - 24 ⁰С in devices “Sterlets”, hatching of larvae occurred through 4,5 - 5 days. Deformities and anomalies of development of spawn over normative it is not marked. Average weight of received business larvae stellat sturgeon - 8 - 12 mg. Rearing made in plastic pools at initial density of landing 50 - 60 thousand larvae/m³ within two weeks on zooplankton up to average weight 100 - 150 mg. The survival rate received young fishes was up to level 63% from planted on rearing larvae.

The Russian sturgeon of Danube (Acipenser gueldenstaedti colchicus) reproduced at the end of May on base “Caviar House”. Took from catch 4 females in weight 25 - 30 kg and males 15 - 18 kg. Fishes injected by Nerestin-5А (0,2 ml/kg for females twice with an interval 12 hours under the scheme of 20% + 80% and 0,1 ml/kg for males unitary right after a preliminary injection for females) at 18 - 20 ⁰С. Working fruitfulness of females has made 180 thousand pieces spawn, percent of fertilisation – 84%, hatching – 75%. Young fishes translated on the active mixed feed by zooplankton and pipe (“trubochnik”) up to weight 300 mg, but the output has made 48% in view of absence during necessary time of a forage and displays of cannibalism. This parameter for the same reason cannibalism has been reduced at young stellate sturgeons and, especially, at young paddle-fishes. By 20 thousand pieces younger sturgeon in weight 5 g it is let out on fish-breeding in Danube, other молодь is now raised in plastic pools on artificial forages. 100% manufacturers have survived; females have let out to Danube, males utilized.

Reproduction of beluga is carried out from individual copies of wild manufacturers from river Danube during the period from 01.03. for 27.04.2004. A place of work - a facilities “Caviar House”, settlement Isakcha, Romania. Preparation Nerestin -5А, a date of issue 04.03.2002 г, a series 14 and additionally a series 10 from 16.01.2003 is used. Female of beluga in weight about 150-160 kg, length 265 cm, preliminary, up to injections, maintained in plastic pool. The total amount of the entered preparation of this female at t⁰ = 10,5 ⁰С has made 34 ml in three injections (a delay of ovulation and necessity of the third injection have been connected to a mistake in definition of weight of a fish). In 12 hours after last injection (20% more over a settlement doze of 0,2 ml/kg) ovulated spawn in quantity of 12 kg has been received. Sperm from three wild males of beluga in average weight 97 kg selected in 8-10 hours after unitary injection a preparation in a doze of 0,1 ml/kg, or 9,7 - 10,0 ml on a fish. In one gramme of spawn contained 39 pieces spawn. Duration incubation has made 7 days at eclosion 88%. Younger fishes on an active feeding of zooplancton and pipe (“trubochnik”) translated in glass-fibre plastics pools at density of landing of 60 thousand in pieces/m3. In 20 days rearing up to 500 mg weight the output of younger fishes has made 52,5%.

Another female of beluga in weight 180-200 kg, length 286 cm was injected twice (20% + 80%) in the general doze of 0,1 ml/kg Nerestin-5B with a date of issue of 02.03.2004. This female had a penetrating wound on depth 5 - 6 cm in an occipital part at a level of the third back “zhuchka”. However and this fish has in due time given ovulated spawn in quantity of 18 kg. From three males of beluga at a doze of this preparation of 0,05 ml/kg have received sperm. Survival rate of manufacturers after injections and operations – 100%. The percent of fertilisation of spawn has made 88%, eclosion – 79%.

Beluga females after selection of spawn at the presence of the commission are let out to Danube, males are utilized. Received younger fishes of beluga in weight 8 - 10 g in quantity of 60 thousand pieces Danube was stocked with fish on a site of Isakcha- Braile (Romania).

On the given materials of beluga artificial reproduction in 2004 film (at authors) is turn out. The third reproduction of this fish in 2004 with help Nerestin-5А was independently executed by employees of the Center of fish culture from Galatz. In Russia and the world of other examples of beluga reproduction in 2004 is not present.

Reproduction of a sterlet (Acipencer ruthenus) both caught in Danube, and brought up from larvae in fresh-water pond in Moldova, with help Nerestin-5 in a doze of 0.4 ml/kg while is carried out in the limited quantity, but with result ovulation and spermiation 100%. These works, after some perfection of a preparation, will be scaled in 2005.

Thus, the lead work has shown high enough efficiency and reliability of application of preparation Nerestin-5(5А, 5B) for replacement hypophysis injections at reproduction of sturgeon fishes and paddle-fish. The additional information on materials of clause can be received at the reference on an e-mail address polyodon@mail.ru or in the guest book of a site http://nerestin.narod.ru.

Authors express gratitude for the given opportunities of tests of preparation Nerestin-5(5А, 5B) on sturgeon fishes to the doctor of biology V.V.Lobchenko (SIFFS, Kishinev), to the doctor of biology of the Center on fish culture in Galatz Nikulae Patrickie, to director of firm “Caviar House” Marilena Maeryanu, to director SIFFS “Nuchet” Miuara Kostake and the supervisor of studies of this station Mikhai Kostake.

ARTIFICIAL REPRODUCTION OF STURGEON FISHES IN ROMANIA AND MOLDOVA.

Vedrashko A.I.

The resume.

In the article the data on artificial reproduction with the help of Russian preparations Nerestin-5(5А, 5B) sturgeon fishes Polyodon spathula, Acipenser stellatus, Acipenser gueldenstaedti colchicus, Huso huso, Acipenser ruthenus in Moldova and Romania in 1995 - 2004 are resulted. The applied dozes of preparations and schemes of their introduction, quantity and quality of the received sexual products are specified at ovulation at females and spermiation at males, percent of fertilisation of spawn, an output raised larvae and younger fishes after growing, survival rate of fishes and other parameters.

Results specify high efficiency of application Nerestin-5 and his analogues in artificial reproduction of sturgeon fishes and Polyodon spathula.