SIMULATION MODEL FOR THE REPRODUCTION OF Airus maculatus (THUNBERG, 1792) Vincent T. Lapinig Governor Alfonso D. Tan College Johnny Mark M. Bolante Northwestern Mindanao State College of Science and Technology ABSTRACT The study made use of simulation and Monte Carlo to study the population dynamics of Arius maculatus using the seed information provided by two recent papers on the reproductive biology of the fish namely Isa et al. (2012) and Chu et al.(2011). Results revealed that under the parameters utilized in these two studies, the population of the fish species would eventually decline towards extinction. On the other hand, further simulation similarly showed that the fish population could be saved through either the declaration of Marine Protected Areas or Seasonal Fish Banning. Keywords: simulation, Monte Carlo, population dynamics, airius maculatus 1.0 Introduction Airus maculatus (Thunberg, 1792), locally known as “tambangongo” is a benthic species in tropical and subtropical waters, inhabiting the bottom of estuaries, rivers and coasts (Chu et al. 2011). Isa et al. (2012) studied the biology of a related genus, Airus argyropleuron, and found an average absolute fecundity of mature ovary to range from 19 to 87 eggs. On the other hand, Chu et al. (2011) estimates the age, growth and mortality of Airus maculatus off the coast of Yunlin, Southwestern Taiwan. Apart from these studies, very few studies had been done on the biology of spotted catfish and even much less on its population dynamics. This paper purports to analyze