Aqua-Internship Program Asia Link Project Faculty of Fisheries Bangladesh Agricultural University, Mymensingh

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1 Aqua-Internship Program Asia Link Project Faculty of Fisheries Bangladesh Agricultural University, Mymensingh Effect of Temperature on the Monosex Tilapia (Oreochromis niloticus) Egg Production in a Private Hatchery and Nursery System Name of Intern : Md. Adibul Islam Name of MS Supervisor : Professor Dr. Md. Abdul Wahab Name of field Supervisor : A. B. M. Shamsul Alam (Badol) Name of Aqua-Farm : Agro 3 1

2 Aqua-Internship Program Asia Link project Faculty of Fisheries Bangladesh Agricultural University, Mymensingh Report on Effect of Temperature on the Monosex Tilapia (Oreochromis niloticus) Egg Production in a Private Hatchery and Nursery System Name of Intern : Md. Adibul Islam Name of M.S. Supervisor : Professor Dr. Md. Abdul Wahab Department of Fisheries Management Name of field Supervisor : A. B. M. Shamsul Alam (Badol) Name of Aqua-Industry : Agro 3 Fish Hatchery and culture farm... Prof. Dr. Md. Abdul Wahab M. S. Supervisor.. A.B.M. Shamsul Alam (Badol) Field Supervisor... Md. Adibul Islam Intern M.S. in Fisheries Management Roll No.10 Fish.FM-JD-10M 2

3 Content Sl. No. Topics Pages 1 Introduction 5 2 Global Climate change Tilapia egg production Effect of Temperature 11 5 Result and discussion Possible Mitigation 13 7 Conclusion 13 8 References 14 3

4 Abstract An internship program was conducted at a renowned private Fish hatchery and culture farm named Agro 3 in Trishal Upazilla, Mymensingh for a period of 3 months to acquire practical knowledge and skill the effect of temperature on then monosex tilapia (Oreochromis niloticus) egg production. Commercial tilapia production generally requires the use of male monosex populations. Male tilapia grows approximately 30% as fast than the females. Moreover, the presence of female tilapia leads to uncontrolled reproduction, excessive recruitment of fingerlings, competition for food and space thus resulting in stunting of growth and delay to reach marketable size. So, monosex male tilapia fry production is important for commercial tilapia culture. But in the recent few years, due to the excessive temperature, the tilapia egg production is remarkably reduced. The aim of this internship was to study the various technical aspects of egg collection of tilapia at various temperature to find out that which temperature is suitable for the collection of eggs and which temperature is best for the higher egg collection. Besides, what measures should be taken for the maintenance of the temperature was one of the aim in this internship program. Keywords: Nile Tilapia(Oreochromis niloticus), 17α methyl testosterone, Water temperature( C) 4

5 Introduction The climate change is an important issue now a days; various human activities are making the world hot to hotter. The variation in the global climate or in the regional climate over time, such as-variation in sunlight intensity, drought, green house gas emission, temperature rise, extreme temperature, unexpected rainfall, arsenic contamination losses of ecosystem which caused by processes of internal and external forces. Bangladesh is extremely vulnerable to climate change impacts because of its geographical location, high population density and high level of poverty and the reliance on livelihoods on climate sensitive sectors particularly on fisheries. Climate change has direct and indirect impacts on fish stocks that are exploited commercially. Direct effects on physiology and behavior which are growth, development, reproductive capacity, mortality and distribution. Indirect effects alter the productivity, structure and composition of the ecosystem on which fishes depend for their food and shelter. Due to climate change, the hatchery farms face various types of problems such as drying up water bodies, eggs not well fertilized, lower hatching rate, late fry availability, shrinking breeding cycle, over heat hamper breeding, lower growth/survival, deform fry, loss of crops etc. Temperature as a Climate change factor Temperature plays an important part in determining the conditions in which living matter can exist. Temperature is very essential for the egg production in a hatchery system but due to excessive temperature the egg production hampered and the hatchery operator can not reach in its optimal production. From the recent few years, the temperature has risen 1to2 C that has highly effected the fish egg production. Temperature plays the most vital role as a main climate change factor not only in the human being but also in the animals; both aquatic and terrestrial and fishes are highly effected due to the excessive temperature. Fry production is the hatcheries are hampered due to the excessive temperature. On the other hand, high temperature may increase the phytoplankton production in the hatchery system that also produce phytoplankton bloom. O 2 level in the water may decrease due to the excess degradation of organic substances that will increase the mortality rate of fishes. Moreover, various types of microorganisms are also found in the high temperature that also increases the probability of diseases contamination. Global Climate change at a glance Greenhouse gases occur naturally in the environment and also result from human activities. By far the most abundant greenhouse gas is water vapor, which reaches 5

6 the atmosphere through evaporation from oceans, lakes, and rivers. The amount of water vapor in the atmosphere is not directly affected by human activities. Carbon dioxide, methane, nitrous oxide, and ozone all occur naturally in the environment, but they are being produced at record levels by human activities. Other greenhouse gases do not occur naturally at all and are produced only through industrial processes. Human activities also produce airborne particles called aerosols, which offset some of the warming influence of increasing greenhouse gases Fig: Atmospheric concentration of carbon dioxide (CO 2 ) and methane (CH 4 ) Global warming of a few degrees may increase agricultural production, but not necessarily in the same places where crops are grown now. Crops and woodlands may be afflicted by more insects and plant diseases. Agricultural areas will need to adapt to changing conditions, such as by shifting the types of crops grown or investing in drought-tolerant or heat-tolerant varieties. Scientists estimate that warming of up to about 3 Celsius degrees (5.4 Fahrenheit degrees) could increase global agricultural potential, but that further warming is likely to decrease this potential Fig: Global Temperature Change since 1980 from GISS data 6

7 Period of high temperature gradually prolonging, i.e in the year 2008, we found high temperature upto 36 C in the month January-July. In the year 2009 we found temperature upto 38 C from May to August. But it has changed in the current years, it starts from May and prolong upto October and the remarkable temperature was sometimes 40 C. Impact of temperature of fisheries: Temperature plays a vital role in the fisheries sector. In the recent few years, due to the global warming, a remarkable effects have been found in this sector due to the excessive temperature. However, the following effect are found in the fisheries sector due to high temperature: Fry production in the hatcheries are hampered. Excess production of phytoplankton pollute the water. O 2 level in the water decrease due to the excess degradation of organic substances that will increase the mortality rate of fishes. PL mortality rate will increase if the temperature is above 23 C. Various types of diseases may be found in fishes. Fishing ground may be changed. If the migration time and the reproduction are changed, variation in species will be reduced. Tilapia(Oreochromis niloticus) egg production in hatchery farm( Agro-3) in different temperature: Egg collection starts from the 1 st week of March in every year and generally it ends at the late October depending on the temperature. Sometimes the ending period may be earlier because of the rainy season. There are around 210 female and 70 male brood fishes stocked in the Agro-3 hatchery farm. About 20-25% eggs are collected from each hapa but in the recent few years, due to high and excessive temperature, the collection rate is decreasing. In the hatchery farm, eggs are categorized in to 3: 2 no. eggs indicates fertilized eggs but not yet hatched. 3 no. eggs indicates eggs that already hatched. 4 no. eggs indicates hatched and swim up larvae. Sometimes in the rainy season, the number of egg collection increased. The fish farmer thought that this is due to the showering. 7

8 Fig 1: Egg collection from hapa in Agro-3 hatchery farm After collecting the eggs from the hapa, they are kept in different hatching jar and hatching tray. Proper rearing is done there for the incubation in the hatching jar. Each batch of fertilized eggs needs on an average about days to complete the cycle of development. Fig 2: Tilapia eggs incubation in hatching tray During the internship program, the egg collection data was collected from July to September. During this period, the temperature was relatively high and the egg collection was not satisfactory according to the hatchery owner. During the egg collection period, the temperature was between 30 to 35 C. The following data shows that generally the egg collections are a little bit satisfactory between C. In different temperature, the egg collection data was collected using two different hapas. In every temperature, eight pairs of hapa (16 hapa) are used for the egg collection. The hapa size was 40 20ft. During the egg collection process, we used small size beaker. Here, 1 beaker = 100 gm ;100 gm contains pcs. of eggs 8

9 The following tables show the amount of egg collection in different temperature: Table 1: During two different temperatures, the eggs were collected in different times at 35 and 34 C. Egg collection at 35 C Egg collection at 34 C Sl. No. Sl. No. 1 25, , , , , , , , , , , , , , , , Total Total Table 2: During two different temperatures, the eggs were collected in different times at 33 and 32 C. Egg collection at 33 C Egg collection at 32 C Sl. No. Sl. No. 1 3, , , , , , , , , , , , , , , , Total Total

10 Table 3: During two different temperatures, the eggs were collected in different times at 31 and 30 C. Egg collection at 31 C Egg collection at 30 C Sl. No. Sl. No. 1 3, , , , , , , , , , , , , , , , Total Total Effect of temperature on tilapia egg production in the hatchery: Due to high temperature, the egg production rate is decreased. Temperature is one of the most vital factors for tilapia egg production. From the above table, it indicates that generally in C, the maximum fish egg collection is done. But with the increasing of the temperature, the amount of eggs is reduced. Moreover, due to high temperature the fertilization is also reduced. Sometimes it is seen that because of the high temperature, the hatching rate increased but it also increase the mortality rate. Nile tilapia did not lay eggs when water temperatures went down below 19 o C. The most productive period coincided with the rise in water temperature to C where spawning rate averaged 40 and 73% of total female s under dark and natural photoperiod conditions, respectively (Brummett, R.E. 1995). But our study shows that between C, we can get the optimum production. But the fish farmer told that, in the recent few years, the amount was relatively high. 10

11 Quantity of eggs Quantity of eggs Quantity of eggs Quantity of eggs Series1 Series2 Series Series1 Series2 Series3 Series4 0 25,26 27,28 19,20 7,8 9,10 11,12 15,16 1,2 0 5,6 17,18 21,22 27,28 1,2 24,26 11,12 9,10 Fig 3: Quantity of eggs collected from different hapas in 35 and 34. The collection highest was and when the temperature was 35 and 34 C but comparison with the other data, it is the lowest production. The figure shows the reduction of eggs number with the increase of temperature Series1 Series2 Series Series1 Series2 Series ,12 15,11 1,2 3,4 29,30 27,28 25,26 23,24 21,22 23,24 25,26 27,28 18,19 11,12 9,10 1,2 Fig: Quantity of eggs collected from different hapas in 32 and 30 C. Relatively in 32 and 30 C, the egg production rate is high. This study indicates that, in the recent years when temperature is increasing gradually, we can get optimum egg between the ranges from C. 11

12 Series C 31 C 32 C 34 C 35 C Fig: Quantity of egg production in different temperature ( C) Result and discussion: In this study, reproduction is best at water temperatures in the range of o C. In subtropical regions with a cool season, the number of fry produced will decrease when daily water temperature averages less than 23 o C. After 16- to 20- day spawning cycles with g Nile tilapia, fry recovery was about 600 fry per female brooder at a water temperature of 27 o C, but only 250 fry per female at 23 o C. Optimal water temperature for tilapia growth is about 28 to 30 o C. Growth at this optimal temperature is typically three times greater than at 23 o C. This study shows that optimum egg collection is possible between the temperature ranges of C. 30 C 31 C 32 C 34 C 35 C Fig 6: Percentage of quantity of egg collection in different temperature( C) This study was mainly conducted to indicate that with the increasing of global temperature due to climate change, not only the fisheries, agricultural and overall socio-economic conditions are effected but also the different hatchery and nursery 12

13 system are highly in great loss due to excessive temperature. Every year the hatchery and nursery owner facing different problem and they are also deprived from a higher portion of profit. Though we get a optimum number of eggs from this study, but the farm owner said that in the previous years, the quantity of eggs was much higher. It was also recorded that about eggs/hapa were also collected. In this study period, the average temperature was 33 C and in this temperature we got the maximum egg collection between C. But generally C is good for the maximum egg collection of Nile tilapia (Oreochromis niloticus). Possible mitigations: In the selected fish hatchery and culture farm (Agro-3), some measures are taken to keep the temperature in the optimum condition in order to obtain the maximum egg from the Nile tilapia. It is not always possible to manage temperature because it is often expensive and reduce the amount of profit. Because electricity, generator and extra manpower is required for the maintenance of water temperature. The following mitigations are taken in the selected farm: Water exchange is a good way for maintaining the temperature. Water temperature is done here. It is usually done for 2-3times/week. Sometimes the surface water are removed from the nursery and brood pond. Water level of the pond are increased sometimes to maintain the temperature. Conclusion: Tilapia is a good fish for warm water aquaculture. But in the recent few years, the tilapia hatchery owners are facing some problems due to the high temperature. They are also depriving from the better profit. Like the selected farm, the mitigations technique should be practiced in other farsm. Besides Nile tilapia are easily spawned, use a wide variety of natural foods as well as artificial feeds, tolerate poor water quality, and grow rapidly at warm temperatures. These attributes, along with relatively low input costs, have made tilapia the most widely cultured freshwater fish in tropical and subtropical countries. Consumers like firm flesh and mild flavor of tilapia, so markets have expanded rapidly in the world wide during the last 10 years. Tilapia farming is gaining popularity day by day in Bangladesh and a number of entrepreneurs have already initiated its hatchery development for commercial monosex seed production and farming in different parts of the country. So in conclusion we can say that tilapia farming has a bright future in Bangladesh. 13

14 References: Brummett, R.E. (1995). Environmental Regulation of Sexual Maturation and Reproduction in Tilapia. Reviews in Fisheries Science, 3 (3): Beardmore, J.A., Mair, G.C. & Lewis, R.I. (2001). Monosex male production in finfish as exemplified by tilapia: applications, problems, and prospects. Aquaculture, 197,