Anabas testudineus
By: Hussain Mat Din

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Puyu Hapus Aedes Di Parit
MELAKA - Lebih 100 ikan puyu dilepaskan ke dalam parit di Taman Seri Duyong Fasa Dua, dekat sini yang dikesan sebagai tempat pembiakan nyamuk aedes.
Pelepasan ikan puyu itu dijangka memusnahkan jentik-jentik yang dihasilkan nyamuk berkenaan.
Ikan puyu itu dilepaskan Ahli Dewan Undangan Negeri (Adun) Kawasan Duyong, Gan Tian Loo, di parit berkenaan, baru-baru ini.
Gan berkata, pelepasan puyu ke dalam parit sepanjang hampir 500 meter itu dilakukan sebagai usaha berterusan menghapuskan kawasan pembiakan nyamuk aedes.
Katanya, walaupun parit itu dibina dua bulan lalu, ia dipenuhi sampah-sarap selain permukaannya juga tidak rata dan menyebabkan airnya mengalir tidak sempurna.
Beliau berkata, jika keadaan parit itu dibiarkan, ia dikhuatiri membolehkan nyamuk aedes bertelur dan menyebabkan deman denggi di kawasan sekitarnya.
"Untuk peringkat permulaan kita melepaskan lebih 100 puyu ke dalam parit dengan harapan ikan itu makan jentik-jentik di dalamnya.
"Saya lihat banyak jentik-jentik di dalam parit ini dan dalam masa terdekat, kita mengambil langkah lain termasuk semburan kabus untuk menghapuskan tempat pembiakannya," katanya.
Sentral difahamkan, Majlis Bandaraya Melaka Bersejarah (MBMB) menjalankan gotong-royong untuk membersihkan parit itu.
Selain itu, Gan berkata, sampah-sarap di dalam parit itu datang dari sekitar taman perumahan termasuk kampung berdekatan.
"Saya berharap penduduk terutama peniaga sama-sama menjaga kebersihan parit ini dengan tidak membuang sisa pepejal atau sampah-sarap termasuk plastik dan sebagainya," katanya.

Petikan dari Berita Harian, Isnin, 14 Februari 2005

– A Case Study of Hyderabad.

Mosquito problem for mankind is ever known and their prevalence is increasing day by day. There are many kinds of mosquitoes and each of which has a different habitat, among which sewage water in urban areas is predominant. In urban areas other than sewage water, mosquitoes hardly find any suitable place for their breeding. These mosquitoes transmit dreadful diseases, and produce intense annoyance and distress to human beings, which is considered a public health problem.
To extirpate the mosquito problems from the targeted water body, its chemical analysis has to be evaluated in terms of its pollution quantity, such as organic and inorganic pollutants so as to establish tolerance threshold of a larvivorous fish in sewage water. As the sewage water quality significantly varies from place to place and community to community.
In developed countries the sewage system is planned and its variations in terms of organic and inorganic pollution is not significant. In these developed countries there is no chance for mosquitoes to take shelter for breeding activity except after treatment, wherein larvivores are introduced for effective control of mosquito larvae.
But in most of the developing countries sewage system is open type and facilitates every chance for mosquito multiplication. There are very few reports on biological control of mosquito larvae in sewage water from Japan, China, Cuba, California and Indonesia. In Indian context biological control of mosquito larvae in sewage water by larvivores has not been reported, except a note released by Vector Control Research Center (VCRC) Pondicherry, wherein it was mentioned that guppy can be introduced in drains for effective control of mosquito larvae. The reasons for success and failure of this particular fish in sewage water are not clearly worked out.
Therefore, Chemical analysis of sewage water in accordance to biological control of mosquito larva was felt essential for the present study. The sewage water quality has been estimated for over a period of two years and variations were established, in terms of its concentrations of organic and inorganic pollutants along with temperature fluctuations. The parameters analyzed show significant correlation with each other, the organic pollutant like Suspended solids, Biochemical oxygen demand, Chemical oxygen demand and inorganic pollutants like Phosphates and Nitrates are recorded highest in Summer months and lowest in rainy seasons, which can be attributed to the dilution factor.
In the present study three larvivorous fish were selected while keeping their merits and previous research findings for evaluation and effective control of mosquito larvae in municipal sewage water. They are Gambusia affinis holbrooki, Poecilia reticulata, and Anabas testudineus.
Gambusia affinis holbrooki is also commonly known as mosquito fish and its larval feeding efficacy in fresh and stagnant-water is undeniable and better than any other larivore. Even, there are few reports (Castleberry and Cech, 1990) on its introduction in sewage water, but that sewage water could be either with lower concentration of sewage pollution or a treated sewage or secondary treated sewage water. Because in the present findings, Gambusia affinis holbrooki had not been proved effective in sewage water.
A good number of reports on mosquito larval feeding efficacy of Poecilia reticulata and its tolerance to sewage pollution are known, but its success and failure in terms of sewage concentration has not been defined by any previous findings (Bay and Self 1972). Another interesting fish selected for present investigations was Anabas testudineus, due to its ability to survive in sewage water and due to its bimodal respiration and accessory air-breathing organ, which is assumed for successful survival and mosquito larval feeding in sewage water. The study of behavioural changes of fish in sewage water and fresh water is investigated to understand differences between two different habitats. The tested fish have shown three different behaviours i.e., Surface stay, Vertical and Horizontal migration, and Bottom stay. It is well known that Gambusia affinis holbrooki and Poecilia reticulata are surface feeders, and Anabas testudineus is a bottom feeder. But the differences are significant with respect to Gambusia affinis holbrooki that projects their abnormal behaviour in sewage water in contrast to fresh water. Two other fishes did not significantly differ in their normal behaviour in both fresh and sewage water habitats.
In the present investigations, the mosquito larval density in the sewage water from the selected study area has been estimated, from the present findings it is found that the density of mosquito larvae are seasonal specific and water current dependent. The occurrence of mosquito larvae represents three major genera, i.e., Aedes, Culex, and Anopheles. The mosquito larval representatives of Aedes and Anopheles were more in rainy season, and Culex represents more in winter season than in other seasons.
In the present investigation the survival rate of selected larvivorous fish was compared between fresh and sewage water. The survival rate can be determined by several factors in different habitats. It is found that the survival rate of Gambusia affinis holbrooki in fresh water was gradually decreased and it is clear that the survival rate of this fish is water quality dependent. But the two other fishes i.e., Poecilia reticulata, and Anabas testudineus were sturdy and with few exceptions their over all survival rate was almost constant in both water habitats. In general the survival rate is more in fresh water than sewage water, but in winter season Poecilia reticulata exhibited quite different results, wherein it is found that 50% in sewage water and 27% in fresh water. This phenomenon can be correlated to temperature fluctuations in different mediums.
Mosquito larval feeding efficiency in selected larvivorous fish (Gambusia affinis holbrooki, Poecilia reticulata, and Anabas testudineus) in fresh and sewage water, reveals that their feeding abilities in fresh water is undeniable, and present findings are comparable to other earlier works. But in sewage water, Poecilia reticulata proved to be more efficient than other fishes. The fate of so called 'mosquito fish' Gambusia affinis holbrooki that struggles for its life in sewage water, and feeding on mosquito larva was not noticed. On the other hand Anabas testudineus though adjusted to sewage water but it was not comparable to guppy, where it is comparably sluggish in sewage water.
From the observations, Poecilia reticulata has emerged as a successful larvivorous fish to suit the desired purpose (i.e., in sewage water for biological control of mosquito larva). Therefore it was felt essential to evaluate the physiological adaptations of particular fish both in sewage and fresh water. The physiological studies are limited and confined to metabolic alterations such as Carbohydrates (Glycogen, and Glycogen Phosphorylase activity), Proteins (Total proteins, free amino acids, Aspartate aminotransferase and Alanine aminotransferase) and Lipids (Total lipids and free fatty acids). As the sewage water is a new environment for test animal and as soon as it was shifted, it underwent stress and to compensate, the energy required was derived from utilizable form of Glycogen. In the present finding glycogen content in sewage water was decreased significantly on 12hrs, 24hrs and 48hrs of introduction, and there after as it is the glycogen content gradually and significantly increased till 4th week of introduction.
Glycogen Phosphorylase activity in the fish had significantly differed between types of water, On 12hrs of introduction in comparison to control, the enzyme activity increased in the fish in sewage water leading to breakdown of the glycogen. In fresh water there was no demand for glycogen breakdown, because the test animal had no stress effect. Till the second day of introduction Glycogen Phosphorylase activity was significantly high in sewage water, and there after with due acclimatization to sewage water, the activity has decreased. However over all observations of Glycogen Phosphorylase activity was more in sewage water than fresh water, which can be attributed to over dependence on Glycogen. This may be due to depleted oxygen level or pollution stress in sewage water.
The total Protein content was less in both the type of waters than the control through out the observation period, but significantly differed between the types of water. In sewage water total protein content was significantly reduced after 24hrs of introduction, and again gradually increased till 1st week of introduction, there after the decreasing trend continued. The decreasing trend can be attributed to the pattern of changes in metabolism, which may be influenced by the distribution of the food in take and biosynthetic purposes. The present finding supports that, the sewage water facilitated fish to feed upon the available food after due acclimatization and ultimately converted it to protein. Where as in fresh water the total protein content gradually decreased throughout the observation period, with an exception on 1st and 3rd week of introduction where the protein metabolism was significantly increased.
In the present findings the lipid level was less than that of control and significantly differed between two different water bodies in comparison to control. On the other hand the variations of total lipid content did not differ significantly throughout the observation period in sewage water. The free fatty acid levels in fish from sewage water is significantly reduced on 12hrs and 24hrs of introduction, there after it varied significantly upto 1st week of introduction, and again the free fatty acid level remained constant till the end of experiment period. Whereas the variations in the levels of free fatty acids in fresh water are significantly differed throughout the observation period and more than the control on 4th week of introduction, which may lead to the biosynthetic processes for energy requirements. Thus it can be assumed that the animal shared a biochemical adaptation lead to the success of the animal in sewage water.

SOURCE: http://www.osmania.ac.in/PG-College-Siafabad/abstract.htm

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