- A bioenergetics model for an air-breathing fish,
Qin, Jianguang; He, Xi; Fast, AW
Environmental Biology of Fishes [Environ. Biol. Fishes]. Vol. 50, no. 3, pp. 309-318. Nov 1997.
Food consumption, standard metabolism, and growth of juvenile snakehead, Channa striatus, a cannibalistic and air-breathing fish were measured at 24-26 degree C under controlled laboratory condition. Snakehead weighing 3.2-29.5 g were evaluated, and were fed smaller snakehead. Based on our observations, we determined bioenergetics relationships between specific food consumption, metabolic rates, and body weight. These values, along with other published parameter values allowed us to construct a bioenergetics model for snakehead. We then verified our model with growth and food consumption measurements from an independent feeding trial. Predicted fish growth closely matched observed growth. Our model underestimated cumulative food consumption when a constant activity value was used, but consumption estimates improved when we used nonconstant activity values (1-5 times of standard metabolism). Predicted fish maintenance ration was 1.7% of body weight per day. Food conversion efficiency was greatest (0.59) when fed 2% body weight daily, but declined when daily consumption exceeded 6% body weight. This model provides a useful approach for assessing food requirements of snakehead under controlled condition.
- Aspects of the reproductive biology of female snakehead (Channa striata Bloch) obtained from irrigated rice agroecosystem, Malaysia
Hydrobiologia [Hydrobiologia]. Vol. 411, pp. 71-77. Sep 1999.
Snakeheads (Channa striata), collected for one year from February 1992 from the rice fields and the contiguous irrigation and drainage canals of North Kerian, Perak, Malaysia, were studied. There were six developmental stages of oocytes. Oocyte size frequency distribution and frequency of occurrence for the different ovarian stages indicated that gonadal development occurs throughout the year. Multi-modal oocyte size frequency distribution in the population indicated the presence of developing as well as mature oocytes in the females also confirms spawning readiness throughout the year. Estimates of mean absolute fecundity ranged from 4326 to 9017 oocytes whereas estimates of mean relative fecundity ranged from 10.5 to 36.3 oocytes per g body weight. Both TL (cm) and weight (g) can be used for estimating fecundity.
- Length-weight relationship and fecundity of Channa punctatus
Journal of Ecobiology [J. Ecobiol.], vol. 8, no. 2, pp. 095-098, Jun 1996
The length-weight regression slopes of male and female Channa punctatus was significant (P<0.005) while their elevation exhibited non significant difference. The relationships between fecundity-length and fecundity-weight were significant (P<0.005).
- The Amur snakehead Channa argus warpachowskii in the Talas and Chu river basins.
VOPR. IKHTIOL./J. ICHTHYOL., vol. 31, no. 5, pp. 864-867, 1991
The Amur snakehead found its way into the Aral Sea basin in the early 1960s and was first recorded in the basins of the Talas and Chu rivers (Kazakhstan) in the mid-80s. The paper presents data on the morphological characters, growth, condition factor and feeding of the fish from water storage reservoirs.
- Food and feeding ratios of the Amur snakehead, Channo argus warpachowskii , in water bodies in the lower reaches of the Amu Darya.
Journal of Ichthyology [J. ICHTHYOL.], vol. 30, no. 4, pp. 11-21, 1990
Consideration is given to the seasonal dynamics and local differences in the feeding of the snakehead (Channa argus warpachowskii ), an introduced species, in the lower reaches of the Amu Darya. Calculations are made of daily and annual food consumption, and of the feeding ratios for various snakehead age groups.
- Feeding intensity and dynamics of juvenile northern snakehead, Channa argus, under different illumination
Xie, Congxin; Xiong, Chuanxi; Zhou, Jie; Wan, Xinmiao; Jin, Hui
Acta hydrobiologica sinica/Shuisheng Shengwu Xuebao. Wuhan [Acta Hydrobiol. Sin./Shuisheng Shengwu Xuebao]. Vol. 21, no. 3, pp. 213-218. 1997.
The feeding intensity of juveniles of the Northern snakehead Channa argus was influenced by light intensity. Under the strong light of 10 super(3) lx, the feeding intensity was relatively weak, but strong under the weak light of 10 super(-3) lx. The feeding intensity increased with the continuous weakening of light intensity. The feeding rate of the juveniles varied with light intensity. The highest feeding rate was observed under 10 super(-3) lx. An optimum illumination found for the feeding. The feeding rate decreased with the feeding time. The feeding dynamics of the juveniles in different feeding conditions, that is the curve of feeding dynamics, was similar in trends to the curves of feeding intensity and feeding rate.
- Predatory behaviour of a snakehead fish (Channa striatus Bloch).
Das, M; Chakraborty, SC; Ahmed, F; Basak, RK
Bangladesh Journal of Fisheries Research [Bangladesh J. Fish. Res.]. Vol. 2, no. 2, pp. 127-137. 1998.
The predatory behaviour of a snake-head, Channa striatus on Labeo rohita fingerlings was studied in the laboratory. The study was conducted with six C. striatus (120-210 g and 22-28 cm) over 24h a day for 3 weeks. Three different sizes prey of large (2.00g and 5.8cm), medium (1.30g and 4.5cm) and small (0.72g and 3.5cm) were used for the first week and then medium size prey for 2nd and 3rd weeks. All the predators preferred eating the small group of L. robita, although all three size groups of L. rohita offered were available. It was found that the prey fishes remained together aside of the aquarium from the predator. Predator first targeted a prey, drove fast towards it, the prey tried to escape from the predator's attack using a specific route and finally the predator grasped the prey by the head and then engulfed it. The handling time ranged between 45 and 50 sec. The time of peak feeding was found in the morning and in the evening of day. When 2 or 3 predators were kept in one aquarium, they engaged in fighting, head on, followed by an attack on the mouth region by the dominant one, and subsequently on the pectoral fin and caudal fin of the defeating one. After 2-3 days they became accustomed to remain together and did not involve themselves in fighting.
- Predation by Channa striatus (Bloch) on Rana tigrina (Daudin), Puntius gonionotus (Bleeker) and Labeo rohita (Hamilton) in the laboratory.
Das, M; Sultana, N; Alamgir, MH; Hossain, MA; Islam, MS
Bangladesh Journal of Fisheries Research [Bangladesh J. Fish. Res.]. Vol. 3, no. 2, pp. 123-129. 1999.
The growth performance of a predatory snakehead, Channa striatis was tested by supplying tadpoles of Rana tigrina and fingerlings of Puntius gonionotus and Labeo rohita as prey for a period of 21 days in aquaria. Prey consumption by C. striatis was significantly different for different prey used (T super(1)-R. tigrina, T sub(2)-P. gonionotus, T sub(3)-L. rohita). Tadpoles of R. tigrina was prefered by the predator (C. striatus) over P. gonionotus and L. rohita although tadpole is nutritionally inferior to each of P. gonionotus and L. rohita. Each predator preyed on 50-330 mg per day per g of their body weight. Fish preyed on tadpoles also showed the highest growth. Significant difference in weight gain was found between T sub(1) and T sub(2) and also between T sub(1) and T sub(3) but no difference was found between T sub(2) and T sub(3). Food conversion ratio (FCR) was found to be lowest in treatment T sub(3), followed by the treatments T sub(2) and T sub(1), respectively.
- Effects of feeding rates on growth and feed utilisation of murrel fingerling, Channa striata (Bloch) and determination of protein to energy requirement for maintenance and maximum growth
Samantaray, K; Mishra, K; Mohanty, SS
6th Asian Fisheries Forum Book of Abstracts. p. 219. 2001.
Two experimental diets, containing 35% crude protein (P35) and 1628.4 kj digestible energy and 45% crude protein (P45) and 2088.8 kj digestible energy with protein to energy (P/E) ratio of 21.5 mg protein kj super(-1) in both diets, were fed at incremental rates (0, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0 and 5.0% of body weight day super(-1)) (13W. d super(-1)) to murrel fingerlings (Channa striata) for 8 weeks. An increase in growth rate of fingerlings was observed up to 10.5 g protein (kg BW. d) super(-1) and 488.51 kj energy (kg BW. d) super(-1) in P35 diet and 11.25 g protein (kg BW. d) super(-1) and 522.20 kj energy (kg BW. d) super(-1) in P45 diet, of which the former diet produced fish better than the later at feeding levels of 3% and 2.5% BW. d super(-1), respectively. Regressing growth rate, obtained for both the diets, to zero weight gain resulted in a maintenance requirement of 0.3-g protein (kg BW. d) super(-1) and 16.6 kj energy (kg BW. d) super(-1). The net gain in body protein also increased linearly with increasing feeding rates up to 10.5 g protein (kg BW. d) super(-1) and 488.51 kj energy (kg BW.d) super(-1) in P35 and 11.25 g protein (kg BW. d) super(-1) and 521.99 kj energy (kg BW. d) super(-1) in P45. Regression equations from the data obtained with the P35 diet predicted that 1.58 g protein (kg BW. d) super(-1) and 71.4 kj energy (kg BW. d) super(-1) was required to maintain a constant amount of tissue protein in fingerlings. But with P45 the protein and energy intake levels have insignificant effects on carcass protein. The effect of feeding rate on feed, protein and energy conversion efficiency and proximate composition were also examined.
- Survivability of Channa punctatus (Bloch) in different kinds of containers
Alam, MM; Parween, S
Pakistan Journal of Zoology [Pak. J. Zool.]. Vol. 33, no. 3, pp. 259-260. 2001.
Channa punctatus (Bloch) is an air breathing fish. In starved condition this fish can live an average of 68.83 days in plastic, aluminium or earthen containers at 26.5-29 degree C. Cannibalism on the weaker partner was observed. The fish also feeds on its own excreta.
- Adaptation of the alimentary tract to feeding habits in four species of fish of the genus Channa.
Indian Journal of Fisheries [Indian J. Fish.]. Vol. 47, no. 3, pp. 265-269. 2000.
The structure and morphometrics of the alimentary canal of Channa orientalis, C. punctatus, C. striatus and C. marulius are described in relation to their food and feeding habits. The general pattern of the alimentary canal was found to be similar and of carnivorous type in the four species studied. C. striatus was found to be the most carnivorous as indicated by the structure and morphometrics of the alimentary canal and nature of gut content followed by C. marulius and C. orientalis was found to be the least carnivorous. Pattern of the mucosal folds in the different regions of the alimentary canal showed inter and intra-specific variations.
- Food and feeding habits of Channa species from East Godavari District (Andhra Pradesh)
Rao, LM; Ramaneswari, K; Rao, LV
Indian Journal of Fisheries [Indian J. Fish.]. Vol. 45, no. 3, pp. 349-353. 1998.
A comparative study on the food and feeding habits of three Channa species from different ponds, tanks and canals of Kothapeta mandal revealed that the feeding of Channa orientalis are different from that of C.punctatus and C. striatus. The preferential feeding habits of the three species have been highlighted. The relation between different maturity stages and feeding intensity is also presented.
- Food consumption and growth of two piscivorous fishes, the mandarin fish and the Chinese snakehead
Liu, J; Cui, Y*; Liu, J
Journal of Fish Biology [J. Fish Biol.]. Vol. 53, no. 5, pp. 1071-1083. Nov 1998.
Rates of maximum food consumption and growth were determined for immature mandarin fish Siniperca chuatsi (47 times 2-540 times 2 g) and Chinese snakehead Channa argus (45 times 0-546 times 2 g) at 10, 15, 20, 25, 30 and 35 degree C. The relationship between maximum rate of food consumption (C sub(max)), body weight (W) and temperature (T) was described by the multiple regression equations: lnC sub(max)=-4 times 880+0 times 597 lnW+0 times 284T-0 times 0048T super(2) for the mandarin fish, and lnC sub(max)=-6 times 718+0 times 522 lnW+0 times 440T-0 times 0077T super(2) for the Chinese snakehead. The optimum temperature for consumption was 29 times 6 degree C for the mandarin fish and 28 times 6 degree C for the Chinese snakehead. The relationship between growth rate (G), body weight and temperature was ln(G+0 times 25)=-0 times 439-0 times 500 lnW+0 times 270T-0 times 0046T super(2) for the mandarin fish, and ln(G+0 times 25)=-6 times 150+(0 times 175-0 times 026T) lnW+0 times 571T-0 times 0078T super(2) for the Chinese snakehead. The weight exponent in the growth-weight relationship was -0 times 83 for the mandarin fish, but decreased with increasing temperature for the Chinese snakehead. The optimum temperature for growth was 29 times 3 degree C for the mandarin fish, but tended to decrease with increasing weight for the Chinese snakehead, being 30 times 3 degree C for a 45-g fish, and 26 times 1 degree C for a 550-g fish.
- Effects of temperature, size and density on culture performance of snakehead, Channa striatus (Bloch), fed formulated feed
Qin, JG; Fast, AW
Aquaculture Research [Aquacult. Res.]. Vol. 29, no. 4, pp. 299-303. Apr 1998.
- Tolerance of snakehead Channa striatus to ammonia at different pH
Qin, Jianguang; Fast, AW; Kai, AT
Journal of the World Aquaculture Society [J. World Aquacult. Soc.], vol. 28, no. 1, pp. 87-90, Mar 1997
Tolerance of snakehead Channa striatus to ammonia was tested at three pH levels (8.0, 9.0, and 10.0) in experimental tanks. At pH 8.0, ammonia LC50 estimates for snakehead at 24, 48, 72, and 96 h were >205.7, >203.5, 152.6, and 107.3 mg total ammonia-nitrogen (TAN)/L (or >10.3, >10.2, 7.6, and 5.4 mg NH sub(3)-N/L), respectively. At pH 9.0, ammonia LC50 estimates at 24, 48, 72, and 96 h were >52.4, 62.8, 56.1, 43.4 mg TAN/L (or >18.0, 21.6, 19.3, and 14.9 mg NH sub(3)-N/L), respectively. At pH 10.0, ammonia LC50 estimates at 24, 48, 72, and 96 h were 25.7, 21.6, 20.3, and 18.7 mg TAN/L (or 21.6, 18.1, 17.1, and 15.7 mg NH sub(3)-N/L), respectively. Our data indicate that the tolerance of snakehead to ammonia was associated with pH. Thus, we recommend that snakehead should not be subjected to prolonged exposures of NH sub(3)-N concentration more than 0.54 mg/L at pH 8.0, more than 1.49 mg/L at pH 9.0, or more than 1.57 mg/L at pH 10.0.
- Growth and survival of larval snakehead (Channa striatus) fed different diets
Qin, Jianguang; Fast, AW; DeAnda, D; Weidenbach, RP
Aquaculture, vol. 148, no. 2-3, pp. 105-113, Jan 1997
Culture performance of larval snakehead (Channa striatus) was examined in a three-phase feeding experiment. During Phase I, diet treatments included: no food (NF); formulated feed only (FF); live Artemia nauplii and decapsulated Artemia cysts (LA); decapsulated Artemia cysts only (DC); formulated feed plus live Artemia nauplii (FA); and formulated feed plus Artemia cysts (FC). Fish survivals during Phase I were, respectively, 82% (FA), 78% (LA), 46% (FC), 30% (DC), and 0% (NF, FF). Fish fed DC were longer and heavier than fish in the other treatments. Phase II was a transition period to wean fish onto formulated diets. During Phase III, only formulated feed was provided. Fish previously fed LA had significantly greater (P<0.05) non-cannibalism mortalities than any other treatment. Fish previously fed FC were heavier than fish in other treatments. We concluded that snakehead could be trained to accept formulated feeds using either of the following methods: (1) feed with Artemia nauplii supplemented with formulated feed for 30 days, then gradually eliminate live food over a 7- to 10-day period; or (2) feed larval snakehead exclusively with live Artemia nauplii for 30 days, followed by 7 to 10 days mixed feeding with both live Artemia and formulated feed, then switch completely to formulated feed.
- Food selection and growth of young snakehead Channa striatus
Qin, Jianguang; Fast, AW
J. Appl. Ichthyol./Z. Angew. Ichthyol. Vol. 13, no. 1, pp. 21-25. 1997.
Food selection and growth of young snakehead Channa striatus were studied in the laboratory and in a field trial. In the laboratory, first-feeding snakehead larvae of 6-7 mm total length (TL) with a mouth opening of 0.55 mm selected for Artemia nauplii, and against formulated feed. Fish began feeding on formulated feed at 12 mm TL when their mouth width reached 1.0 mm. In both laboratory and field trials, snakehead diets changed as fish size increased. For fish 15-20 mm TL, cladocerans and copepods were 96.5 % of their diet. With fish 30-40 mm TL, zooplankton consumption was greatly reduced while benthic organism consumption increased. Fish 45-50 mm TL fed exclusively on benthic invertebrates. Diet shift from zooplankton to benthic invertebrates was not due to reduced zooplankton availability, but was instead related to changes in gill raker structure. Low density of benthic invertebrates in the field trial caused reduced fish growth rates when fish switched diets from zooplankton to benthos. Our results indicate that snakehead can take Artemia nauplii as a larval starter food, then accept formulated feed at greater than or equal to 12 mm TL. Zooplankton can serve as food for snakehead < 40 mm, but formulated feed should be provided for larger fish which are unable to catch zooplankton.
- Size and feed dependent cannibalism with juvenile snakehead Channa striatus
Qin, Jianguang; Fast, AW
Aquaculture, vol. 144, no. 4, pp. 313-320, 1996
A linear regression model was developed to predict cannibalism in juvenile snakehead Channa striatus. Based on morphological measurements of mouth width, head width and body length, the model relates maximum prey length (TL; mm) to predator TL (TLprey =26.168+0.278 TLpredator). This model was verified with a set of independent data, indicating an underestimate of maximum prey size for a certain predator size. The revised model should be: TL prey=25.809+0.405 TLpredator (mm). Size differences substantially increased the rate of cannibalism, but prey:predator TL ratios decreased with increased predator TL. Cannibalism rate was 100% during a 5 day trial when the TL ratio of smaller fish to larger fish was 0.35; but the cannibalism rate decreased to 43% when the TL ratio of smaller fish to larger ones increased to 0.64. Increased availability of formulated feed also reduced cannibalism. With no feed offered, cannibalism was 83%; but decreased to 43% when daily feeding rate was 15% of the larger fish's body weight. Our results indicate that cannibalism is unavoidable with this species, but can be greatly reduced among juvenile fish by size grading and ad libitum feeding.
- Effects of feed application rates on growth, survival, and feed conversion of juvenile snakehead Channa striatus
Qin, Jianguang; Fast, AW
Journal of the World Aquaculture Society [J. WORLD AQUACULT. SOC.], vol. 27, no. 1, pp. 52-56, 1996
Growth, survival and feed conversion ratio of juvenile snakehead Channa striatus were evaluated when fed a dry, formulated feed (50% crude protein) at 24 plus or minus 1 C. Six daily feed application rates were used (0%, 5%, 10%, 15%, 20%, and 30%), as a percentage of fish body weight, with three replicates per treatment. After 29 d, final weights were all significantly greater (P < 0.01) than initial weights, except for the 0% application. Feed applications higher than 5% did not result in increased growth (P > 0.05). Feed conversion ratio was 0.99 at 5% feed application, and 6.3 at 30% feed application. Fish survival was increased by providing formulated diet, but no further improvement was found when feed applications exceeded 5%. Cannibalism was reduced by providing formulated feed, but it was unavoidable when substantial differences in fish size existed, even when feeding ad libitum. Our results indicate that the optimal feed application rate is close to 5% body weight/d for juvenile snakehead.
- Effect of slaughter house pollution on the biochemical composition of Channa orientalis
Hymavathi, V; Rao, LM
Journal of Environmental Biology [J. Environ. Biol.]. Vol. 22, no. 3, pp. 209-212. Jul 2001.
The present study deals with the biochemical composition of Channa orientalis from a habitat polluted by slaughter house wastes in comparison to an unpolluted habitat of Mudasarlova stream of Visakhapatnam. The total proteins, carbohydrates and lipids were found to be less in the organisms collected from the polluted habitat. The probable reasons for these variations are discussed in detail.
- Seasonal variation in the biochemical composition of juvenile Channa striatus (Bloch).
Mohanty, SS; Samantaray, K
The Third Indian Fisheries Forum, Proceedings, 11-14 October, 1993, Pant Nagar, U.P.. pp. 191-192. 1996.
Juvenile Channa striatus, were studied for seasonal variations in their biochemical composition. Though no significant variations was observed in the moisture content of the fish in an annual cycle, a significant variation was observed in the body protein, fat and ash content. The data was correlated with the reproductive cycle and water temperature.
- Interactions of dietary levels of protein and energy on fingerling snakehead, Channa striata
Samantaray, K; Mohanty, SS
Aquaculture [AQUACULTURE]. Vol. 156, no. 3-4, pp. 245-253. 1 Nov 1997
A 4 x 3 factorial experiment was conducted to determine the optimum protein to energy (P/E) ratio for fingerling snakehead (Channa striata). Four crude protein levels and three energy levels at each protein level were utilized. Laboratory-made brown fish meal was used as the major source of protein in all the test diets. Each of the experimental diets was fed to triplicate groups of 15 fingerlings with an average individual weight of 12 g in 110-l flow-through fibre blast tanks at 28 plus or minus 2 degree C, with 5.9 to 7.2 mg dissolved oxygen l-1. The diets were fed at a rate equalling 3 wet body wt% day-1 in two equal rations and adjusted weekly for 8-weeks. The highest growth was attained by fingerlings fed a 40% protein diet with a P/E ratio of 90.9 mg protein kcal-1 digestible energy. A lower but not significantly different (P>0.05) growth response was attained by fingerling fed a 45% diet with a P/E ratio of 93.8 mg kcal-1. Protein efficiency ratio (PER) was affected by the increase in energy level from 400 to 480 kcal 100 g-1 at all protein levels except 40% where a diet with energy 440 kcal 100 g-1 showed maximum PER value. The lowest feed conversion ratio (FCR) was obtained at an P/E ratio of 90.9 mg protein kcal-1. Carcass moisture content was not affected by dietary P/E ratio. Other changes in carcass composition due to the change in dietary P/E ratio were not consistent. This study also indicated that a lipid level of 13% can be effectively utilized by snakehead fingerlings without any adverse effects.
- Sublethal effects of pesticides on feeding energetics in the air breathing fish Channa striatus
Ramakrishnan, M; Arunachalam, S; Palanichamy, S
Journal of Ecotoxicology & Environmental Monitoring [J. Ecotoxicol. Environ. Monitoring]. Vol. 7, no. 3, pp. 169-175. Jul 1997.
The sublethal effects of endosulphan, malathion and hexavin on food intake, growth and conversion efficiency of the air-breathing fish Channa striatus have been studied. It was found that all parameters of food utilizations in pesticide-treated fish were altered with increasing concentrations of pesticides. The food consumption rate decreased from 170.2 cal g super(-1) d super(-1) (pesticide - free water) to 82.4, 90.4 and 87.8 cal g super(-1) d super(-1) when the fish was reared in the highest sublethal concentrations of endosulpha, malathion and hexavin, respectively. The conversion rate of the fish reared in the maximum sublethal concentrations of endosulphan (0.0008 ppm), malathion (0.4 ppm) and hexavin (1.5 ppm) medium decreased from 84.2 cal g super(-1) d super(-1) (pesticide-free water) to 22.4, 27.4 and 18.3 cal g super(-1) d super(-1), respectively. The net conversion efficiency (k2) also decreased from 51.7% to 30.5, 35.6 and 24.5% when the fish was reared in the maximum sublethal concentration of endosulphan malathion and hexavin medium, respectively.
- An Overview of Freshwater Cage Culture in Thailand
Lin, CK; Kaewpaitoon, K
Cage Aquaculture in Asia: Proceedings of the First International Symposium on Cage Aquaculture in Asia. pp. 253-257. 2000.
Despite its long history and a large number of rivers and reservoirs in Thailand, cage culture contributed only 0.3% of 200,000 tons in total fish production from freshwater aquaculture. Over the last decade, the peak of annual fish production from freshwater cages reached 2,700 tons in 1991 and declined since to a minimum of 600 tons in 1995. Although cage culture takes place in various habitats such as river, reservoirs, irrigation canals and large ponds, its predominant habitats are in flowing waters. Among a dozen of cultured species, red snake-head (Channa micropeltes), catfish (Pangasius spp.), marble goby (Oxyeleotris marmoratus) and tilapia (Oreochromis spp.) topped the list. The production of those species fluctuated drastically resulting mainly from deteriorating water quality, competing for trash fish feed, changing market value, and shifting culture practices. However, disease and fingerling supply caused the reduction and limitation in culture of the most valued marble goby. Recently, the cage culture of tilapia has gained great popularity in certain parts of the country. Cage culture has been a small-scale, artisanal operation with little research and technical innovation. Further development of cage cultures in freshwater lies on ecologically sound multiple uses of reservoirs and flowing waters. In addition, integration of intensive cage culture with semi-intensive species in ponds should also be promoted.