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