| 英文摘要 |
A: The giant snakehead（Channa micropeltes）larva in the Tsengwen Reservoir water areas was sampled monthly with a fishing net from April 1, 2009 to December 30, 2009. A total of 837 fish and weight of 11,422.07g were collected sampled weekly during the period from September 1, 2009 to October 15, 2009. The average body length 99.89±17.08(mm)and weight 12.98±5.78(g) of the giant snakehead larva were sampled six weeks. The average body length add to 16.64(mm) and weight add to 12.16 of the giant snakehead larva used the investigations and the data were statistical analyzed. The results of growth current showed W=2E-0.5L2.873 that the relationship between average length (L) and weight (W) were analyzed with the linear regression. The gut contents of the giant snakehead larva were analyzed that the results showed the major food items were fresh water shrimps (Macrobrachium asperulum) and unknown fish fry. According to the feeding habits of the giant snakehead larva were strong carnivores habit and it may have profound effect on the economic fishes in the ecosystem system of Tsengwen Reservoir .
B: The distribution areas of the two invasive crayfish - Procambarus clarkia and Cherax quadricarinatus are still expanding in Taiwan. The distribution of Cherax quadricarinatus was only in the southern Taiwan three years ago,however, it has spread to Chiayi in the investigation of this year. Metaldehyde is a legal molluscicide in Taiwan for control of apple snail. This study investigated the toxicity of metaldehyde to these two invasive crayfishes. The result showed, Procambarus clarkia has higher tolerance than Cherax quadricarinatus, The half-lethal concentration (LC50) of metaldehyde to Procambarus clarkia is over 20 mg L-1, whereas to Cherax quadricarinatus is 17.9 mgL-1.
C:? Procambarus siamensis (the glass fish) was one an Invasive alien species (invasives) of the in middle Taiwan. (e.g. Sun-Moon Lake). Furthermore, It was create fisherman resulted in economically losses. To remove aquatic invasives was not an ease assignment. |
