Ismail Nahed M M, El Gamal Abd El Rahman A
Department of Environmental Research and Medical Malacology, Theodor Bilharz Research Institute, Imbaba P.O. Box 30, Giza, Egypt.
J Egypt Soc Parasitol. 2003 Aug;33(2):413-24.
The abundance of snail species in earthen fish ponds, irrigation and drainage canals at World Fish Center (ICLARM) in descending order was Bellamya unicolor (50.89%) > Physa acuta (18.94%) > Cleopatra bulimoides (7.6%) > Lanistes carinatus (6.73%) > Bulinus truncatus (5.19%) > Melanoides tuberculata (4.83%) > Lymnaea natalensis (3.14%) > Gabbiella senaariensis (0.9%) > Biomphalaria alexandrina (0.55%) > Lym naea truncatula (0.4%) > Planorbis planorbis and Succinea cleopatra (0.33%) > Ferrissia isseli (0.18%). Dead snails constituted about 5.19% of all the collected specimens. There were dramatic decrease in the total number of pulmonates in fish ponds which contained only Tilapia sp., and a very small number of cat fish, whereas the numbers of prosobranchia snails were much higher in these ponds. In fish ponds which accommodated a variety of fish species, the most dominant snail was B. unicolor followed by L. carinatus. However, pulmonate snails were absent in these ponds. B. truncatus was the only snail species found in concrete tank which contained only young tilapias with a very small size (5-8 cm in standard length). In irrigation canals, the number of snails and diversity was much higher than those in fish ponds. Out of 191 snails collected from inlet irrigation canal, 71 were dead, but in the outside irrigation canals, seven out of 564 snails were dead. P. acuta was absent in all examined fish ponds, but it was alive and in a high number (497 snails) in the outside irrigation canals. The number of snails collected from Bahnasawy drain was remarkably low (128 snails), however the diversity of snails was much higher compared to those in fish ponds and irrigation canals. Snail populations were stable with constant recruitment of young to adult snails for all the studied species.
世界渔业中心（ICLARM）的土池、灌溉排水渠中蜗牛种类的丰富度从高到低依次为：纯色环棱螺（50.89%）＞尖膀胱螺（18.94%）＞埃及扁卷螺（7.6%）＞隆背蜒螺（6.73%）＞截形小泡螺（5.19%）＞瘤拟黑螺（4.83%）＞纳塔尔椎实螺（3.14%）＞塞纳里加贝螺（0.9%）＞亚历山大双脐螺（0.55%）＞截形椎实螺（0.4%）＞扁卷螺和埃及琥珀螺（0.33%）＞伊氏费里螺（0.18%）。死蜗牛约占所有采集标本的5.19%。仅养殖罗非鱼和少量鲶鱼的池塘中肺螺亚纲蜗牛总数急剧减少，而这些池塘中前鳃亚纲蜗牛的数量要多得多。养殖多种鱼类的池塘中，最主要的蜗牛是纯色环棱螺，其次是隆背蜒螺。然而，这些池塘中没有肺螺亚纲蜗牛。截形小泡螺是仅养殖小规格（标准体长5 - 8厘米）幼罗非鱼的混凝土池中发现的唯一蜗牛种类。在灌溉渠中，蜗牛数量和种类多样性比池塘中高得多。从灌溉渠进水口采集的191只蜗牛中有71只死亡，但在外部灌溉渠中，564只蜗牛中有7只死亡。所有检测的池塘中均未发现尖膀胱螺，但在外部灌溉渠中它数量众多且存活（497只蜗牛）。从巴纳萨维排水渠采集的蜗牛数量极少（128只蜗牛），不过与池塘和灌溉渠相比，蜗牛种类多样性要高得多。所有研究种类的蜗牛种群都很稳定，幼蜗牛不断成长为成体。
