According to su 2008 there has been an increase in

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According to Su (2008), there has been an increase in dengue incidences in the country, especially in Metro Manila, caused by various reasons related to weather. This is further proven by Sumi (2016) in which as it has been observed in this study that despite the difference in years, there is still an inflation of numbers regarding dengue cases. In response to this on-going epidemic, the government of Dagupan City, Pangasinan has resorted to the use of mosquito fish to eradicate carrying mosquitoes. Six thousand mosquitofishes has been released and introduced to fresh waters in the city as an act of preventive measures regarding the outbreaks (Yparraguirre & Pasion, 2019). 2.3.3 Population Growth Rate in Other Countries
Mulla & Hurlbert (1981) observed that during the experiment the Gambusia affinis would have occupied the volume of most ponds (starting number of Gambusia affinis in 12 ponds are 0, 50, and 450) with intertwining paths that connects them with each other. Pond measures 4 x 6 m and an approximate depth of 0.5 meters by the end of the first or second month stating likewise that the Gambusia affinis is a prolific species (Smith, 1912). Gambusia affinis was already used by the United States as a biological type of controlling the larval phase of the mosquitos as early as 1905 when it was linked that mosquitos carry sicknesses such as malaria. Gambusia was spread artificially by the allied forces to countries from the United States to New Zealand, Australia and the Philippines. (Ling, 2004). 2.4 Impacts of the Introduction of Mosquitofish Introduction of the Mosquitofish in a foreign environment may lead to several changes in the economic balance of an ecosystem and it is dependent on several factors that will either benefit, such as eating the mosquito larvae, or harm it based on the different interactions with other fishes where it is placed. 2.4.1 Positive Impacts of Mosquitofish Introduction Since the early 1900's, Gambusia affinis is suitable for the elimination of the mosquito larvae hence the name mosquitofish (Myers, 1965). According to Hildebrand (1919), that in a controlled setting where mosquito larvae can not hide, they are forced in an open area where the fish immediately detects their movement and are eaten instantaneously. However during the trial, the researcher observed that mosquito larvae can breed in an acidic environment where the fish can be killed instantly. Hildebrand (1919) emphasized in order to acquire a more practical result the amount of fish needs to be many but it is indifferent because of fast reproduction rate. On a separate extended study done by Hildebrand (1922), found out that a single pair of half-grown mosquitofish can eliminate 5,041 mosquito larvae. Through this, it summarized the abilities of the mosquito fish, which are the following: habitable in mosquito larvae areas, preference of live animals as food, able to reproduce quickly in different environments where mosquitoes breed and is capable of multiplying quickly.

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