预防逃逸是人工饲养河蟹的重要措施之一。圈养在蟹塘中的河蟹,因受密度、生活条件和活动范围所限,它攀缘逃逸的习性表现得十分激烈。河蟹为了外逃,成群结队,攀登不息。有的饲养单位,防逃设施不全,河蟹往往大量逃逸而未被察觉。因此,在建造河蟹饲养塘时,必须建造完备的防逃设施。其种类很多,下面介绍几种较为常用、制作方便、防逃效果较好的设施,有玻璃贴坡、预制水泥板围壁、平瓦檐式、网条封面、竹棚等,它们各有优缺点,现分述于后。一、玻璃贴坡玻璃贴坡是河蟹防逃的理想方法之一,养蟹时应用较为普遍。它不但适用于土坡的饲养池,也适用于水泥预制板、砖石砌坡的饲养池。玻璃贴坡的方法:将30～45厘米的玻璃条用水泥或石灰砌在坡 Prevention and escape is one of the important measures to raise crabs by hand. Crabs caged in crab ponds, due to density, living conditions and scope of activities is limited, its habit of climbing escape behavior is very fierce. Crab in order to flee, in droves, climbing endless. Some breeding units, anti-evasion facilities, crabs tend to escape a large number of undetected. Therefore, the construction of crab breeding ponds, we must build a complete anti-escaping facilities. There are many kinds of them. Here are some of the more commonly used, easy to make, anti-escaping effect better facilities, glass sloping, prefabricated cement wall, flat tile canopy, net cover, bamboo shed, etc., Shortcomings, now described later. First, the glass paste slope slope glass is one of the ideal method of anti-escaping crab, crab application more common. It is not only suitable for raising the soil slope pool, but also for cement prefabricated slab, brick stone slope feeding pond. Glass slope approach: 30 to 45 cm of glass with cement or lime in the slope