THESIS APPROVAL

CONCLUSION AND RECOMMENDATIONS
Conclusion
From the experimental results and discussion of this study, the conclusion can
be drawn as follows:
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The investigation on the morphological features of Limnodrilus hoffmeisteri
collected from Chao Phraya estuary revealed that the specimens were totally
immature. By using 10 individuals, the worms had a total length between 20-30
(25.52±3.29) mm with a total segment ranging from 50-90 (64.8±13.34) segments.
The range of weight was varying from 3.154 to 4.557 (3.813±0.46) mg wwt. All bifid
crochets were found, which the upper tooth was shorter and thinner than the lower.
Anterior dorsal bundles were composed of 5-6 setae while ventral bundles were
composed of 6-7 setae. Posterior setae had become reduced in number falling to 2-3
setae which were shorter than the anterior. The results from biological behavior
observation were found that L. hoffmeisteri showed active swimming in the water.
They burrowed and left traces while digging through the sediment. Cluster of
L. hoffmeisteri on the sediment surface was found that they comprehensively pierced
as deep as 4-5 cm. The anterior portion of the worms was hidden in the substrate due
to their feeding habit, and the posterior end was vertically projected and excreted fecal
pellets. Dense colony of L. hoffmeisteri was found beneath the sediment surface
without movement of the posterior end when the overlying water was well aerated.
On the contrary, movement of the tail end was appeared when low level of DO was
recorded. Clump living of L. hoffmeisteri was also found by furnishing cramped
microhabitats.
The estimation on the specific growth and biological activities of
L. hoffmeisteri was done under laboratory condition corporating with the different
level of food addition in the sediments. It could be concluded that the number
individual and weight of the worms increased in the treatment with high level of food
(E-WH) than in the treatment with low level of food (E-WL) after 35 d of the