Ecobiology Character of Midas Cichlid (Amphilophus citrinellus Günther, 1864) as A Basis for Controlling Alien Fish Species in Ir. H. Djuanda Reservoir, West Java.

Abstract

Midas cichlid is an alien fish species found in Ir. H Djuanda Reservoir and known to be disrupting the stability of the native fish population. This research was conducted in order to analyze the ecobiological characteristic of the fish such as food composition, distribution, growth, reproduction, food utilization and food similarity with other fish species in the area. The samples were taken from six stations from October 2011 to January 2012 in Ir. H. Djuanda Reservoir, in the Province of West Java. Gill nets were used with mesh-size of 1, 1,5, 2, 2,5, 3, 3,5 and 4 inches. The total number of fish being caught during those times were 657 individuals, with six of 12 species caught being native species, while the rest were alien species. Midas cichlid dominated the amount of fish caught (460 individuals). This fish has a total body length and weight ranges between 62–210 mm and 4.81–187.18 gram, respectively. The growth pattern showed that this fish is positive allometric. The condition factor of this fish tended to be similar throughout the stations. Midas cichlid was in good condition at the time sampling occurred The sex ratio of midas cichlid was even at 1:1. The size of mature males and females individuals were 125 mm and 121 mm, respectively. Total fecundity ranged between 729–3,299 of eggs. This fish is a partial-spawning type. Midas cichlid is an omnivore species and usually consumed all sorts of food within the feeding ground. The diet of this fish include phytoplankton, zooplankton, mollusks, earthworms and small fish in general. According to the index of preponderance, this kind of fish prefers to eat zooplankton. There were occurence of food ontogenetic variance found from this fish. Other fish species thought to be utilizing in the same way the small-sized, medium-sized, and the large-sized midas cichlid does is Barbonymus balleroides. Midas cichlid is being considered as an invasive spesies in Ir. H. Djuanda Reservoir and its existence should be controlled. The controlling could be done preventively and curatively. Preventive controlling could be conducted by sorting the fry population that would be stocked into the reservoir and by ensuring the fish hatchery used was free from midas cichlid fry. Curative controlling could be done by using a well-planned and scheduled catching method using a 1.5 inches gill nets in the litoral area body of water.