MUD CRAB (Scylla serrata) LARVAE
An Investigatory Project Presented to
the Faculty of the Special Science Class
Iloilo National High School
La Paz, Iloilo City
In Partial Fulfillment
of the Requirement for the Subject
Dominic Paul O. Genson
THE EFFECT OF TREFLAN ON SURVIVAL OF
MUD CRAB (Scylla serrata) LARVAE
DOMINIC PAUL O. GENSON
Background of the Study
Mud crabs belonging to the Genus Scylla are large portunids with high commercial value. Its culture in the Philippines is a significant source of income for farmers. However, a major constraint to grow-out culture activities is insufficient supply of crablets gathered from the natural habitat. To answer this problem, research on larval rearing of mud crab has been intensified. One of the problems that causes low survival in the larval rearing of mud crab is the occurrence of bacterial and fungal infection. Treflan, a fungicide, has been used to prevent the occurrence of fungal infection in some crustaceans. However, the effect of Treflan on the growth and survival of each larval stage of mud crab has not been investigated.
This research about on crabs was conducted because of two reasons. One was to determine the effect of various concentrations of Treflan on the survival of mud crab larvae. The second was to identify the level of Treflan which would be most recommended to use during larval rearing of mud crab.
Statement of the Problem and the Hypothesis
This study aimed to determine the effects of Treflan on the growth and survival of mud crab larvae. It specifically sought answers to the following questions:
1. Is Treflan effective in preventing the occurrence of fungal infection?
2. What id the effect of the various concentrations of Treflan on the survival rate of mud crab larvae?
3. Is there significant difference in the survival of mud crab using different amounts of Treflan?
There is no significant difference in the survival rate of mud crabs at various concentrations of Treflan.
Significance of the Study
Treflan is a widely-used commercial fungicide for mud crabs and other marine crustaceans. Although it had been proven efficient, no one has done research to find out the most effective concentration of Treflan to be used. This research will help in finding the most effective concentration of Treflan to be used.
This will help the many cultivators of mud crabs to give more effective doses of Treflan while, at the same time, increase the mortality rates of their larvae. The result will be more profit and less loss.
Definition of Terms
Mud crab- a group of crustaceans characterized by a reduced abdomen and an enlarged and broadened anterior portion of the body; dig or inhabit burrows in mangroves and soft substrates in shallow and inter tidal waters (Microsoft Encarta Reference Library 2003 and Food and Agriculture organization of the United Nations 1988).
In this study, “mud crab” referred to the test animal in its larval stage obtained from SEAFDEC.
Larva- scientific term for the young of any crustacean that undergoes a complete metamorphosis in the course of development to an adult; larvae is plural form (Microsoft Encarta Reference Library 2000).
In this study “larva” referred to the mud crab organism used in the toxicity test.
Megalopa- mud crab larval stage next to zoea (Ong 1964)
In this study “megalopa” referred to the larval stage of the mud crab during testing.
Development- means to go through a process of natural growth, differentiation, or evolution by successive changes (Merriam- Webster Online).
In this study, “development” referred to the transformation of megalopa to crab instar stage after a given period of time.
ppm- parts per million or milliliter per ton of water (Parado-Estipa et al 1996).
In this study “ppm” referred to the...