Habitat Use of Freshwater shrimps Neocaridina denticulata in the Hapen Creek

Information on habitat use can enhance our understanding to a species’ecological requirements and physiological costraints, then we can make relevant suggestions about conservation and management. Neocaridina denticulata is a very common shrimp speices in Taiwan streams. They play an important role in freshwater ecosystem and an economical species in aquaculture. To understand hibitat use of Neocaridina denticulata, we use electric fishing method to capture shrimps in natural and altered banks of Hapen creek in both non-reprodective ㄈ and reproductive season (May). The aim of the stury is to understand (1) differences in abundance and distribution of shrimps in different seasons and habitat types, (2) habitat use of shrimps along 14 environmental factors, (3) differences in habitat use among different age/sex groups.
During the study period, we found that plants were present only in natural creek banks, but not altered ones. Comparisons between natural banks without plants and altered banks revealed no significant difference in both shrimp abundance and distribution. However, there was significant difference in shrimp abundance when natural banks with plants and altered banks were compared, suggesting that construction might have negative effects on plants and, in turm, on shrimp abudance. Comparisons between reproductive and non-reproductive season yielded significant results in both shrimp abundance and distribution, which resulted from the recruitment of juveniles to local populations. Results of habitat use along 14 environmental factors showed that Neocaridina denticulata appeared at sites with plants, greatrer coverage above water, lower water speed, shallower depths and lower substrate diversity 1m apart. We suggested that sites with the above property serve as shelters against predators, provide more heterogeneous microhabitat and more food. In addition, this study showed that different age/sex groups did not differ in habitat use. Manipulative experiments are needed to further elucidate habitat preference for different age/sex groups.