Spawning response of Sahar (Tor - putitora) in different seasons under pond reared condition in Pokhara, Nepal

Spawning response of Sahar (Tor
putitora) in different seasons under pond
   reared condition in Pokhara, Nepal

          Jay Dev Bista, Bharat K Shrestha, Ram K. Shrestha ,
 Surendra Prasad, Arun Baidya , Madhav K Shrestha and Tek B Gurung

Introduction

 Golden Sahar (Tor putitora) so called “mahseer” is
  popularly known as Sahar in Nepal,
 Two species: T. putitora and T. tor are reported to inhabit
  Nepalese mountainous rocky rivers and lakes of mid hills
 Due to over fishing and physical alterations of their
  surroundings, it is reported to be declining in their natural
  habitats in the past.
 At present attempts to culture and conserve Tor spp. has
  been initiated in most of trans-himalayan countries

Objective of the study

 To determine the breeding behavior and spawning
  season to assure success spawning of Sahar (Tor
  putitora) broods in captive condition.
 To establish mass scale seed production technology for
  biodiversity conservation and food security through ex-
  situ conservation approach.

Methods and materials

                     Brood management

       Description          Female Pond   Male Pond
                 2
         Area (m )              500          500
      Stocking density       1000 kg/ha   2000 kg/ha
        Stocking No          100 female    200 male
    Feeding rate (of BW)        3-4%         3-4%
            pH                 7.0-9.0      7.0-9.0
         DO (mg/L)             5.0-9.0      5.0-9.0
                   0
       Temperature C          12.5-32.0    12.5-32.0
        Depth (cm)             80-90        80-90

     Transparency (cm)         30-50        30-50

Monthly water temperature of brood fish pond

Research ponds at
FRC Pokhara, Nepal

Proximate Composition of pellet feed for sahar brood

         S.N                      Description          %
          1                       Crude Protein        35
          2                        Crude Fat           9
          3                           Ash              7
          4                           Fiber            8
          5                          NFEE*             31
          6                         Moisture           10

*   Nitrogen free ether extract

 Female broods were checked frequently for maturity after
  hauling them by drag net at the bank of the ponds.
 The collected broods were partially anaesthetized in 50 mg/L
  Benzocaine solution and brood were examined by applying
  gentle hand pressure near the genital opening.
 No hormone injection was applied for spawning
 Females releasing ova on slightest pressure were
  transported in inside the hatchery where they were fully
  anaesthetized and stripped gently to receive eggs in clean
  and dry bowl.

Contd …

 Milt from healthy males was directly mixed with eggs for dry
  fertilization.
 Incubation of eggs was took place in running water system
  incubators by allowing one layer of eggs to settle on single
  mesh screen, where water flow was maintained 5-6
  liters/minute.

                                  Maturity
                                  observation of
                                  female sahar

Hatchery operation

     Striping and fertilization

       Striping of eggs           Milt from male

Breeding process…

 Hatchery Operation

Results and Discussion

Spawning performance of Sahar in different season

                                 Sept-Oct 2010   Feb-Mar 2011
          Female, No.                100             100
   Responded female, No. (%)       60 (60%)      100 (100%)
  Normally spawned brood (%)       10 (10%)        46 (46%)
       Over matured (%)            50 (50%)        42 (42%)
        Not spawned (%)            40 (40%)        12 (12%)

   Post spawning mortality (%)        0%             0%

Fecundity:
90,000-100,000 eggs/kg
(No. of eggs: 90-120/g)

Fertility: 80-90 %

Hatchability: 75-95%.

Hatching time:
Depends on water            Striped eggs
temperature (72-120 hrs.)

Size of ovulated eggs, fertilized eggs and size of newly
  hatched larvae and yolk-sac absorbed larvae (mm)

 Female    Diameter of   Diameter of   Size of newly
                                                       Size of yolk-sac
Body wt.    ovulated      fertilized      hatched
                                                       absorbed larvae
   (g)        eggs          eggs           larvae

 2.32       2.27±0.17     2.88±0.12     10.52±0.56       11.81±0.20

 3.95       2.58±0.29     2.87±0.13     10.37±0.27       11.46±0.27

 3.35       2.41±0.11     2.93±0.10     10.14±0.23       12.00±0.21

 2.95       2.28±0.13     2.96±0.08     10.16±0.17       11.98±0.38

  3.50      2.53±0.18     2.98±0.08     10.24±0.29       11.77±0.22

 Female brood get maturity at the age of 3+ years (> 700 g) and
  male at 1 year ( 50-100 g).
 Most of the Sahar brood responded during February-March than
  September-October under cultured condition.
 Almost 100% females attained sexual maturity in pond condition,
 Among which 46% females released viable eggs, 12% females
  released poor quality eggs and rest 42% were found over matured
  during the maturity examination in February-March 2011,
 While only 10% females released viable eggs and 50% were
  found over matured during September-October 2010.
 Early hatched larvae possessed a large yolk sac and settled down
  in the corners of the incubation trays.

Spawning response of Sahar (T. putitora ) in different months

Spring (S/B)
                   Spawned brood of sahar in different season
                                                                                 Spring (O/M)
                                                                                 Autumn (S/B)
                    40
                                                                                 Autumn (O/M)
                    35
                    30
   No. of broods

                    25
                    20
                    15
                    10
                    5
                    0
                         2000   2002   2004   2006   2008   2009   2010   2011   2012

                                                     Year

Spawning behavior of Sahar in spring and autumn season
                    in last few years

Conclusion and Recommendation

 Almost all Pond reared Sahar breed twice in a year in
  two distinct season (spring and autumn) and most of
  the females (>95%) were gained maturity in both
  season
 No reproductive hormone need for breeding of sahar
 The mature broods get over maturity within very short
  time.
 Higher spawning rate can be achieved by frequent
  checking of brood fish in every 1-2 days interval for
  ovulation under captive condition.

Some important breeding protocols to be applied:
   Female brood should be well ripen with bulging abdomen
      and a swollen, soft and elastic genital opening (vent)
     Press gently on abdomen, then slightly move towards the
      vent for checking maturity of the female
     Smooth netting with knotless nets of small mesh
     Careful handling for no injury and less stress, use towels to
      hold the brood
     Broods should be anaesthetized during transportation and
      oxygenation if distance
     Handle the fish very carefully, don’t press more during
      striping and returning back to the pond safely in short time.
     Common salt must be treated before back to the pond.

Research activities
                                   Production technology
      Conservation
                                         (Ex-situ)
        (In-situ)

Phewa Lake

                             Egg incubation         Larvae

Begnas Lake

                                              Growth monitoring

Sahar (Tor putitora) in
                               fisheries and aquaculture

Sahar in cage culture

                        In pond culture

                                          River fisheries for ecotourism

Funding for this travel was provided by the

        The AquaFish Innovation Lab is supported in part by United States Agency for International Development (USAID)
            Cooperative Agreement No. EPP-A-00-06-00012-00 and by contributions from participating institutions.
     This presentation is made possible by the generous support of the American people through the United States Agency for International Development (USAID). The contents are the
responsibility of the authors and do not necessarily reflect the views of USAID or the United States Government. Mention of trade names or commercial products in this presentation does not
 constitute endorsement or recommendation for use on the part of USAID or AquaFish. The accuracy, reliability, and originality of the work presented are the responsibility of the individual
                                                                                            authors.

THANKS