Studies have shown that arachidonic acid (ARA) serves as a precursor for prostaglandins which have a key function in the reproductive process. The objective of this was to manipulate an appropriate ARA level for inducing final maturation and spawning of limpet Cellana sandwicensis and black tiger shrimp Penaeus monodon via broodstock diet. The broodstock were fed with different diets containing various ARA levels ranging from 0.24% to 1.06% for 3 months. The results showed that gonadal somatic index values, eggs diameter, the fecundity, spawning cycle and hatching rate of those broodstock fed with diets containing ARA were significantly (P