Laboratory assessment of feeding-behavior interactions between the introduced Pacific white shrimp Litopenaeus vannamei (Boone, 1931) (Penaeidae) and five native shrimps plus a crab species in Thailand

摘要

The Pacific white shrimp Litopenaeus vannamei (Boone, 1931) is native to the Pacific coast of Central and South America. This species was first introduced to Thailand in 1998 for aquaculture and as a replacement for Penaeus monodon Fabicius, 1798 because of problems with disease outbreaks and poor growth performance of the latter. Escapes of cultured L. vannamei to the wild were detected recently; however, little is known about the effects of the escape of cultured shrimps on the local ecosystems. In this laboratory study, the feeding behavior of L. vannamei was examined and compared with that of five native shrimps and a native crab species to determine the behavioral interactions and potential for food competition. With regards to palatability of the five native shrimp species, L. vannamei was non-selective, consuming the first piece of meat encountered. When all species were tested separately, Litopenaeus vannamei consumed its food faster than the native shrimps. In paired one-on-one contests, L. vannamei was much more aggressive in competing for food than the native shrimp species. When paired with the native crab species, Charybdis affinis, L. vannamei lost 100% of the contests and the crab sometimes killed and ate the shrimp. Due to its behavioural dominance in feeding contests with native shrimps, L. vannamei pose a serious threat to native shrimp species should it become fully established in marine waters of Thailand.