Abu Al Abyad island is characterized by harsh environmental conditions. A preliminary trial conducted at the island to investigate the spawning and hatching performance of the blue finned sea bream Sparidentex hasta indicated that the fish can be successfully bred at high salinity levels exceeding 50 ppt

Ali, A.A.

Kumar, K.K.

Yousif, O.M.

English

Aquatic Commons

13NAGA, WorldFish Center Quarterly  Vol. 26 No. 4 Oct-Dec 2003
articles
Spawning and hatching performance of the 
Silvery Black Porgy Sparidentex hasta 
under Hypersaline conditions
O.M. Yousif, A.A. Ali and K.K. Kumar
Abstract
Abu Al Abyad island is characterized by harsh environmental conditions. A preliminary trial conducted at the 
island to investigate the spawning and hatching performance of the blue fi nned sea bream Sparidentex hasta 
indicated that the fi sh can be successfully bred at high salinity levels exceeding 50 ppt.
Introduction
The silvery black porgy or blue fi nned sea 
bream Sparidentex hasta, known as subaiti 
in the United Arab Emirates, is native to 
the Arabian Gulf, western Indian Ocean 
and coasts of India. It occurs in habitats 
varying from shallow (Fig. 1) coastal 
waters to deep water. The fi sh feeds 
mostly on invertebrates and crustaceans 
(Bauchot and Smith 1984; Kuronuma and 
Abe 1986;  Al-Abdessalaam 1995). 
The fi sh are protandrous hermaphrodites, 
that is, they possess both female and male 
gonadal tissue and mature fi rst as males, 
then become females as they get older 
(Parvez and Ahmed 2000). They are highly 
prized in the region. In the 1980s it was 
recognized that these fi sh possess 
characteristics desirable for aquaculture, 
such as readiness to spawn in captivity, 
rapid growth, and tolerance to a relatively 
wide range of culture conditions (Hussain 
et al. 1981). Hatchery technology for the 
commercial production of fi ngerlings of 
the species was established by the 
National Mariculture Center, Bahrain 
(Al-Ansari et al. 1998). 
The Abu Al Abyad island is situated west 
of Abu Dhabi and has low annual rainfall, 
high evaporation rates, high air tempera-
ture and high humidity. These factors have 
directly contributed to the unusually 
harsh marine conditions prevailing in the 
island. The island is characterized by its 
wide network of natural and artifi cially 
dredged channels that are fringed with a 
substantial expanse of mangrove trees 
(Avecinia marina) and shrubs.
The desirable characteristics for and the 
success achieved in culturing it have 
encouraged the introduction of this fi sh 
into Abu Al Abyad island.  The results of a 
preliminary trial undertaken in the Abu Al 
Abyad hatchery to assess whether this 
species can be spawned and hatched under 
hyper saline conditions, ranging between 
50 and 55 ppt, are presented in this paper.  
 
Fig. 1.  A 2.5 kg female Sparidentex hasta
Fig. 2.  Oval spawning tank with the egg 
collector placed at the overflow water exit
NAGA, WorldFish Center Quarterly  Vol. 26 No. 4 Oct-Dec 200314
articles
Brood stock management
The hatchery bred fi ngerlings were reared 
to sexual maturity in 5x5x2.5 m fl oating 
net cages placed in one of the artifi cially 
dredged channels of the island. During the 
grow-out period the fi sh were fed to 
satiation with a combination of 52 per cent 
crude protein commercial pelleted feed 
and trash fi sh (sardines) enriched with fi sh 
oil (10 g/kg).  At the end of the fi rst year of 
rearing, the S. hasta fi ngerlings in the net 
cages reached a size of 500 g in weight and 
the whole population was observed to 
have matured as males with thick and 
glutinous fl owing milt.  At the end of the 
second year, the fi sh had an average weight 
of 1 kg and some of them were observed 
to have changed sex but had not attained 
complete maturity. In the third year, about 
10 per cent of the population was easily 
distinguishable as females. 
In mid-December 2000 when the fi sh 
were two years old, eighty males with an 
average weight of 1.9 kg (1.30 to 2.50 kg) 
and eighty females with an average weight 
of 2.1 kg (1.60 to 2.75 kg) were 
segregated into two net cages. Beginning 
early January 2002, females with swollen 
abdomens were selected, injected with 
HCG at 400 IU per kg body weight of fi sh 
and kept in a separate net cage.  After 24 
hours a resolving dose of 100 IU/kg body 
weight was administered to the females. 
Immediately after the second injection, 
females and males with free fl owing milt 
were transferred to the hatchery where 
they were stocked for spawning, at a sex 
ratio of 1:1, in an oval 40 t concrete tank 
at a density of one fi sh/m3. Filtered 
seawater was continuously supplied at 40 
l/min, allowing a 200 per cent daily water 
exchange. Fish in the spawning tanks were 
fed squid meat at a rate of two per cent 
body weight. During the spawning season 
the water salinity was constant at 54 ppt 
and the average maximum and minimum 
water temperatures ranged between 18 
to 19 ºC and 22 to 23 ºC, respectively. In 
another identical tank, a second group of 
spawners was also stocked at a sex ratio 
of 1:1 and left to spawn naturally.  
 
Spawning and hatching
The induced fi sh were observed to spawn 
48 hrs after the second hormonal injection. 
The buoyant eggs were directed towards 
the overfl ow opening by the gentle inlet 
water current. Pelagic eggs were collected 
twice daily (8:00 hrs and 17:00 hrs) in fi ne-
meshed 400µ collection buckets placed at 
the overfl ow waters from the spawning 
tanks (Fig. 2). The eggs were then washed 
thoroughly with fresh seawater and placed 
in a measuring cylinder for separation of 
good buoyant fertilized eggs from sinking 
bad eggs as well as for volumetric 
estimates (Fig. 3). To ensure good water 
quality, about 50 per cent of the bottom 
water from the tank was drained out daily 
after the second egg collection in the 
afternoon through a drain exit located at 
the bottom of the tank.
 
Spawning period Lunar cycle
Collected eggs
       Total           good         bad
      (106)            (%)             (%)
Incubation period
(hrs)
Hatching rate
(%)
Water temp. (°C)
 max        min
8 - 13 Jan 2nd quarter       0.99          39.30          60.70 24 6.05   20         19
14 - 27 Jan 1st quarter       3.29          33.70          66.30 30 2.16   19         18
28 Jan - 12 Feb 2nd quarter       3.78          33.40          66.60 42 72.48   19         18
27 Feb - 13 Mar 2nd quarter      16.32          78.80           21.20 22 20.65   23         22
Table 1. Induced spawning and hatching rate of S. hasta in 40 t indoor concrete tanks
The total number of eggs collected from 
30 females during the whole spawning 
period (8 January-13 March) was 24.4 
million eggs at an average of 0.39 million 
eggs per one kilogram of female (Table 1).  
Each female spawned once during this 
period. The good fl oating eggs comprised 
64 per cent of the total number of eggs 
collected. Only buoyant eggs were 
stocked in 600 µ mesh incubators (70 cm 
in diameter and 65 cm in height) placed in 
5 t rectangular fi berglass tanks with fl ow-
through fi ltered and sterilized seawater. 
Eggs were stocked at an average rate of 
300 ml/incubator (approx. 600 000 eggs/ 
incubator). Dead eggs were continuously 
siphoned out from the bottom of the 
incubators.  The average hatching rate was 
only 23.17 per cent of the total incubated 
eggs. The incubation period ranged 
between 42 hrs (at a minimum water 
temperature of 18 ºC) and 23 hrs (at a 
maximum water temperature of 23 ºC).
In the control tank, the fi rst natural 
spawning occurred at the end of January 
and continued till the middle of March. 
The total number of eggs collected from 
30 females was 32.6 million eggs at an 
average of 0.52 million eggs per one 
kilogram of female.  About 81.41 per cent 
of this number were good eggs. The 
average hatching rate was only 27.87 per 
cent of the total incubated good eggs 
(Table 2).
For both the induced and naturally 
spawned groups, spawning was continuous 
at both the fi rst and second quarters of 
the moon, suggesting that spawning of this 
species is not synchronized with the lunar 
cycle. On the other hand, it was observed 
that fi sh spawning activity increased 
following the fl ushing out and sudden 
refi lling of the spawning tanks. This 
suggests that there is a correlation 
between spawning and tidal fl oods or 
currents. Further investigations are 
suggested to test the use of this natural 
trigger in initiating and controlling the 
Fig. 3. Separation and volumetric 
counting of eggs
15NAGA, WorldFish Center Quarterly  Vol. 26 No. 4 Oct-Dec 2003
articles
spawning activity of S. hasta. The 
incubation period was observed to 
increase with decreasing water 
temperature. Owing to limited hatching 
facilities, spawning activity was 
discontinued by the middle of March and 
the spawners were transferred back to 
their respective net cages.  
 
Conclusion
The husbandry procedures applied in this 
trial indicate that hormonal injections are 
unnecessary for spawning induction, 
especially when the water temperature is 
above 20 ºC, and fi sh can spawn naturally. 
The incorporation of polyunsaturated 
fatty acids in the brood stock feed 
improved to some extent the quality of 
the eggs as well as the hatching rate.
Hormonal treatment resulted in poorer 
egg quality and a lower hatching rate than 
Fig. 4. Newly hatched larvae collection from the 600 µ eggs incubators 
Spawning period Lunar cycle
Collected eggs
       Total           good         bad
      (106)            (%)             (%)
Incubation period
(hrs)
Hatching rate
(%)
Water temp. (°C)
 max        min
28 Jan - 12 Feb 2nd quarter     14.46           73.24         26.76 42 20.65   19         18
13 Feb - 26 Feb 1st quarter       3.16           68.35         31.65 30 51.06   21         20
27 Feb - 13 Mar 2nd quarter     14.98           92.05           7.95 22 29.78   23         22
Table 2. Natural spawning and hatching rate of S. hasta in 40 t indoor concrete tanks
natural spawning. However, the spawning 
performance obtained in this trial is 
considered low as compared to those 
reported from other parts of the region 
(Al-Ansari et al. 1998). The cause for this 
low performance is not specifi cally 
known but high salinity could be a factor. 
Towards the end of the spawning season, 
the total number of eggs produced, 
fertilization and hatchability increased 
compared to those obtained at the 
beginning of the season. This might be 
due either to lower water temperatures 
in January or to the immaturity of the 
eggs. These observations suggest that the 
proper spawning season for S. hasta in 
Abu Al Abyad island is between February 
and March. In general, these fi ndings 
indicate that the spawning and hatching 
of S. hasta is possible in the harsh 
environmental conditions of the island 
and plans for mass larvae production 
should be encouraged.
References
Al-Abdessalaam, T.Z.S. 1995. Marine 
species of the Sultanate of Oman.  An 
Identification Guide. Ministry of 
Agriculture and Fisheries, Sultanate of 
Oman, 412 p.
Al-Anasri,  A.A.,  A.A. Al-Bosta, A. H. Al-
Shaikh and A.A. Shawoosh. 1998. 
Production of sobaity bream, 
Sparidentex hasta, larvae and fry at the 
National Mariculture Center 
(NaMaC), Bahrain. National 
Mariculture Center, Directorate of 
Fisheries, Ministry of Works and 
Agriculture. State of Bahrain, 25 p.
Bauchot, M.L. and M.M. Smith.1984. 
Sparidae. In W. Fischer and G. Bianchi 
(eds.) FAO species identification 
sheets for fishery purposes.  Western 
Indian Ocean (Fishing Area 51).  Vol. 4. 
FAO, Rome.
Hussain, N., S. Akatsu and C. Al-Zahr.1981. 
Spawning, egg and early larval 
development, and growth of 
Acanthopagrus cuvieri (Sparidae). 
Aquaculture 22:181-194. 
Kuronuma K. and Y.  Abe. 1986. Fishes of 
the Arabian Gulf. Kuwait Institute for 
Scientific Research, 356 p.
Parvez L.K. and A.M.  Ahmed. 2000. First 
observations on natural sex reversal 
in a protandrous bream (Sparidentex 
hasta: Sparidae) from Kuwait. Pakistan 
Journal of Zoology 32(3):229-243.  
______________________________
O.M. Yousif, A.A. Ali and K.K. Kumar 
are from the Fish and Shrimp Farming 
Project,  Abu Al Abyad, P.O. Box 372,  
Abu Dhabi, United Arab Emirates.
E-mail: onrash@emirates.net.ae


Spawning and hatching performance of the silvery black porgy Sparidentex hasta under hypersaline conditions

The silvery black porgy or blue fi nned sea

bream Sparidentex hasta, known as subaiti

in the United Arab Emirates, is native to

the Arabian Gulf, western Indian Ocean

and coasts of India. It occurs in habitats

varying from shallow (Fig. 1) coastal

waters to deep water. The fi sh feeds

mostly on invertebrates and crustaceans

(Bauchot and Smith 1984; Kuronuma and

Abe 1986; Al-Abdessalaam 1995)

Yousif, Omer M

Ali, A A

Krishna Kumar, K

CMFRI Digital Repository

13NAGA, WorldFish Center Quarterly  Vol. 26 No. 4 Oct-Dec 2003articlesSpawning and hatching performance of the Silvery Black Porgy Sparidentex hasta under Hypersaline conditionsO.M. Yousif, A.A. Ali and K.K. KumarAbstractAbu Al Abyad island is characterized by harsh environmental conditions. A preliminary trial conducted at the island to investigate the spawning and hatching performance of the blue fi nned sea bream Sparidentex hasta indicated that the fi sh can be successfully bred at high salinity levels exceeding 50 ppt.IntroductionThe silvery black porgy or blue fi nned sea bream Sparidentex hasta, known as subaiti in the United Arab Emirates, is native to the Arabian Gulf, western Indian Ocean and coasts of India. It occurs in habitats varying from shallow (Fig. 1) coastal waters to deep water. The fi sh feeds mostly on invertebrates and crustaceans (Bauchot and Smith 1984; Kuronuma and Abe 1986;  Al-Abdessalaam 1995). The fi sh are protandrous hermaphrodites, that is, they possess both female and male gonadal tissue and mature fi rst as males, then become females as they get older (Parvez and Ahmed 2000). They are highly prized in the region. In the 1980s it was recognized that these fi sh possess characteristics desirable for aquaculture, such as readiness to spawn in captivity, rapid growth, and tolerance to a relatively wide range of culture conditions (Hussain et al. 1981). Hatchery technology for the commercial production of fi ngerlings of the species was established by the National Mariculture Center, Bahrain (Al-Ansari et al. 1998). The Abu Al Abyad island is situated west of Abu Dhabi and has low annual rainfall, high evaporation rates, high air tempera-ture and high humidity. These factors have directly contributed to the unusually harsh marine conditions prevailing in the island. The island is characterized by its wide network of natural and artifi cially dredged channels that are fringed with a substantial expanse of mangrove trees (Avecinia marina) and shrubs.The desirable characteristics for and the success achieved in culturing it have encouraged the introduction of this fi sh into Abu Al Abyad island.  The results of a preliminary trial undertaken in the Abu Al Abyad hatchery to assess whether this species can be spawned and hatched under hyper saline conditions, ranging between 50 and 55 ppt, are presented in this paper.   Fig. 1.  A 2.5 kg female Sparidentex hastaFig. 2.  Oval spawning tank with the egg collector placed at the overflow water exitNAGA, WorldFish Center Quarterly  Vol. 26 No. 4 Oct-Dec 200314articlesBrood stock managementThe hatchery bred fi ngerlings were reared to sexual maturity in 5x5x2.5 m fl oating net cages placed in one of the artifi cially dredged channels of the island. During the grow-out period the fi sh were fed to satiation with a combination of 52 per cent crude protein commercial pelleted feed and trash fi sh (sardines) enriched with fi sh oil (10 g/kg).  At the end of the fi rst year of rearing, the S. hasta fi ngerlings in the net cages reached a size of 500 g in weight and the whole population was observed to have matured as males with thick and glutinous fl owing milt.  At the end of the second year, the fi sh had an average weight of 1 kg and some of them were observed to have changed sex but had not attained complete maturity. In the third year, about 10 per cent of the population was easily distinguishable as females. In mid-December 2000 when the fi sh were two years old, eighty males with an average weight of 1.9 kg (1.30 to 2.50 kg) and eighty females with an average weight of 2.1 kg (1.60 to 2.75 kg) were segregated into two net cages. Beginning early January 2002, females with swollen abdomens were selected, injected with HCG at 400 IU per kg body weight of fi sh and kept in a separate net cage.  After 24 hours a resolving dose of 100 IU/kg body weight was administered to the females. Immediately after the second injection, females and males with free fl owing milt were transferred to the hatchery where they were stocked for spawning, at a sex ratio of 1:1, in an oval 40 t concrete tank at a density of one fi sh/m3. Filtered seawater was continuously supplied at 40 l/min, allowing a 200 per cent daily water exchange. Fish in the spawning tanks were fed squid meat at a rate of two per cent body weight. During the spawning season the water salinity was constant at 54 ppt and the average maximum and minimum water temperatures ranged between 18 to 19 ºC and 22 to 23 ºC, respectively. In another identical tank, a second group of spawners was also stocked at a sex ratio of 1:1 and left to spawn naturally.   Spawning and hatchingThe induced fi sh were observed to spawn 48 hrs after the second hormonal injection. The buoyant eggs were directed towards the overfl ow opening by the gentle inlet water current. Pelagic eggs were collected twice daily (8:00 hrs and 17:00 hrs) in fi ne-meshed 400µ collection buckets placed at the overfl ow waters from the spawning tanks (Fig. 2). The eggs were then washed thoroughly with fresh seawater and placed in a measuring cylinder for separation of good buoyant fertilized eggs from sinking bad eggs as well as for volumetric estimates (Fig. 3). To ensure good water quality, about 50 per cent of the bottom water from the tank was drained out daily after the second egg collection in the afternoon through a drain exit located at the bottom of the tank. Spawning period Lunar cycleCollected eggs       Total           good         bad      (106)            (%)             (%)Incubation period(hrs)Hatching rate(%)Water temp. (°C) max        min8 - 13 Jan 2nd quarter       0.99          39.30          60.70 24 6.05   20         1914 - 27 Jan 1st quarter       3.29          33.70          66.30 30 2.16   19         1828 Jan - 12 Feb 2nd quarter       3.78          33.40          66.60 42 72.48   19         1827 Feb - 13 Mar 2nd quarter      16.32          78.80           21.20 22 20.65   23         22Table 1. Induced spawning and hatching rate of S. hasta in 40 t indoor concrete tanksThe total number of eggs collected from 30 females during the whole spawning period (8 January-13 March) was 24.4 million eggs at an average of 0.39 million eggs per one kilogram of female (Table 1).  Each female spawned once during this period. The good fl oating eggs comprised 64 per cent of the total number of eggs collected. Only buoyant eggs were stocked in 600 µ mesh incubators (70 cm in diameter and 65 cm in height) placed in 5 t rectangular fi berglass tanks with fl ow-through fi ltered and sterilized seawater. Eggs were stocked at an average rate of 300 ml/incubator (approx. 600 000 eggs/ incubator). Dead eggs were continuously siphoned out from the bottom of the incubators.  The average hatching rate was only 23.17 per cent of the total incubated eggs. The incubation period ranged between 42 hrs (at a minimum water temperature of 18 ºC) and 23 hrs (at a maximum water temperature of 23 ºC).In the control tank, the fi rst natural spawning occurred at the end of January and continued till the middle of March. The total number of eggs collected from 30 females was 32.6 million eggs at an average of 0.52 million eggs per one kilogram of female.  About 81.41 per cent of this number were good eggs. The average hatching rate was only 27.87 per cent of the total incubated good eggs (Table 2).For both the induced and naturally spawned groups, spawning was continuous at both the fi rst and second quarters of the moon, suggesting that spawning of this species is not synchronized with the lunar cycle. On the other hand, it was observed that fi sh spawning activity increased following the fl ushing out and sudden refi lling of the spawning tanks. This suggests that there is a correlation between spawning and tidal fl oods or currents. Further investigations are suggested to test the use of this natural trigger in initiating and controlling the Fig. 3. Separation and volumetric counting of eggs15NAGA, WorldFish Center Quarterly  Vol. 26 No. 4 Oct-Dec 2003articlesspawning activity of S. hasta. The incubation period was observed to increase with decreasing water temperature. Owing to limited hatching facilities, spawning activity was discontinued by the middle of March and the spawners were transferred back to their respective net cages.   ConclusionThe husbandry procedures applied in this trial indicate that hormonal injections are unnecessary for spawning induction, especially when the water temperature is above 20 ºC, and fi sh can spawn naturally. The incorporation of polyunsaturated fatty acids in the brood stock feed improved to some extent the quality of the eggs as well as the hatching rate.Hormonal treatment resulted in poorer egg quality and a lower hatching rate than Fig. 4. Newly hatched larvae collection from the 600 µ eggs incubators Spawning period Lunar cycleCollected eggs       Total           good         bad      (106)            (%)             (%)Incubation period(hrs)Hatching rate(%)Water temp. (°C) max        min28 Jan - 12 Feb 2nd quarter     14.46           73.24         26.76 42 20.65   19         1813 Feb - 26 Feb 1st quarter       3.16           68.35         31.65 30 51.06   21         2027 Feb - 13 Mar 2nd quarter     14.98           92.05           7.95 22 29.78   23         22Table 2. Natural spawning and hatching rate of S. hasta in 40 t indoor concrete tanksnatural spawning. However, the spawning performance obtained in this trial is considered low as compared to those reported from other parts of the region (Al-Ansari et al. 1998). The cause for this low performance is not specifi cally known but high salinity could be a factor. Towards the end of the spawning season, the total number of eggs produced, fertilization and hatchability increased compared to those obtained at the beginning of the season. This might be due either to lower water temperatures in January or to the immaturity of the eggs. These observations suggest that the proper spawning season for S. hasta in Abu Al Abyad island is between February and March. In general, these fi ndings indicate that the spawning and hatching of S. hasta is possible in the harsh environmental conditions of the island and plans for mass larvae production should be encouraged.ReferencesAl-Abdessalaam, T.Z.S. 1995. Marine species of the Sultanate of Oman.  An Identification Guide. Ministry of Agriculture and Fisheries, Sultanate of Oman, 412 p.Al-Anasri,  A.A.,  A.A. Al-Bosta, A. H. Al-Shaikh and A.A. Shawoosh. 1998. Production of sobaity bream, Sparidentex hasta, larvae and fry at the National Mariculture Center (NaMaC), Bahrain. National Mariculture Center, Directorate of Fisheries, Ministry of Works and Agriculture. State of Bahrain, 25 p.Bauchot, M.L. and M.M. Smith.1984. Sparidae. In W. Fischer and G. Bianchi (eds.) FAO species identification sheets for fishery purposes.  Western Indian Ocean (Fishing Area 51).  Vol. 4. FAO, Rome.Hussain, N., S. Akatsu and C. Al-Zahr.1981. Spawning, egg and early larval development, and growth of Acanthopagrus cuvieri (Sparidae). Aquaculture 22:181-194. Kuronuma K. and Y.  Abe. 1986. Fishes of the Arabian Gulf. Kuwait Institute for Scientific Research, 356 p.Parvez L.K. and A.M.  Ahmed. 2000. First observations on natural sex reversal in a protandrous bream (Sparidentex hasta: Sparidae) from Kuwait. Pakistan Journal of Zoology 32(3):229-243.  ______________________________O.M. Yousif, A.A. Ali and K.K. Kumar are from the Fish and Shrimp Farming Project,  Abu Al Abyad, P.O. Box 372,  Abu Dhabi, United Arab Emirates.E-mail: onrash@emirates.net.ae

Spawning and hatching performance of the

Silvery Black Porgy Sparidentex hasta

under Hypersaline conditions

http://aquaticcommons.org/9589/1/naga-26-4-article3.pdf

Spawning and hatching performance of the silvery black porgy Sparidentex hasta under hypersaline conditions

Abstract

Similar works

Full text

Available Versions

Aquatic Commons

CMFRI Digital Repository