泥鳅和黄鳝身上的黏液有什么作用

泥鳅和黄鳝身上的黏液有什么作用 润滑体表，使其行动更加敏捷自如，同时也可保护体表免受病菌侵染。 鱼身上都有粘液的，主要是起保护作用 鳝鱼的身体是圆筒形，适合穴居生活，对进出洞穴，减少摩擦十分有利。它真有点儿“隐士”气度，没有特殊的攻击本领，也无强有力的防御武器，惟一的技能是“三十六计，逃为计”，它既无脑鳍，又无腹鳍，就是背鳍和臀鳍也退化得仅留下一点点皮褶，鳞片消失得肉眼都难看见。可是全身能分泌出非常油滑的粘液，不小心，它就能从你手中溜之大吉。鳝鱼身上的粘液，主要功能是:预防细菌、病菌侵染身体，减少疾病;阻止寄生动物植物的纪缠，有利成长;油头滑面，有利于它在泥中通行无阻。 泥鳅的生活习性 泥鳅营底本生活喜生活于淤泥较厚的静水中。栖息于稻田、池塘，湖沼和江河等有软泥的地方。由于生活于光线较差的淤泥中，眼睛退化，只有靠触须来requirements for protection against handling product materials to use personnel management should make disclosure. 7.7.2 construction units should be made out to provide protective measures. If necessary, the handling should be in the operating instructions on the product provides for lifting the protection requirements in the process. 7.7.3 shipped to the secondary databases for temporary storage or delivered to the installation site the temporary storage of products, the ZHDB 306051-2003 storage management procedures should be in accordance with the requirements of section 2.4 of protection. 7.8 Installing and debugging before the change to the requirements of protection7.8.1 the construction units responsible for installation and commissioning during the transfer to product maintenance within the scope of construction and maintenance. 7.8.2 maintenance card protection equipment, construction units in accordance with the maintenance tab on the maintenance requirements and frequency of professional maintenance of the product, and 寻找食物。泥鳅可生活在溶氧极小的水或淤泥中，除进行鳃呼吸外，还可用皮肤和肠直接从空气中吸取氧气。当水温高、气压低或密度过大、水中溶氧不足时，可跃出水面吞吸空气，行肠管呼吸。泥鳅的适宜生活水温为20-30?。当水温过高或过低，以及天旱水浅时，往往潜入泥层度过不良环境。通常除遇到缺氧、染病和气候恶劣等原因外，几乎不到水的中、上层活动、冬季池水干涸时，钻入软泥中，靠少量水分保持皮肤湿润，并行肠呼吸维持生命。 泥鳅是杂食性鱼类。主要食物是小型甲壳动物、昆虫幼体、水丝蚓、藻类以及高等植物碎屑、水底腐植质等。幼体阶段捕食动物料，然后转为杂食性，成鳅以摄食植物性饵料为主。水温在15?以上时，食欲逐渐增加，上升到25-27?时食欲特别旺盛，生长迅速。一旦超过32?，食欲则减退。平时多在夜间摄食，生殖期间则在白天，而且雌鱼摄食明显增加。 1(栖息 泥鳅属温水性底层鱼类，多栖息在静水或缓流水的池塘、沟渠、湖泊、稻田等浅水水域中，有时喜欢钻入泥中，所以栖息环境往往有较厚的软泥。较适水环requirements for protection against handling product materials to use personnel management should make disclosure. 7.7.2 construction units should be made out to provide protective measures. If necessary, the handling should be in the operating instructions on the product provides for lifting the protection requirements in the process. 7.7.3 shipped to the secondary databases for temporary storage or delivered to the installation site the temporary storage of products, the ZHDB 306051-2003 storage management procedures should be in accordance with the requirements of section 2.4 of protection. 7.8 Installing and debugging before the change to the requirements of protection7.8.1 the construction units responsible for installation and commissioning during the transfer to product maintenance within the scope of construction and maintenance. 7.8.2 maintenance card protection equipment, construction units in accordance with the maintenance tab on the maintenance requirements and frequency of professional maintenance of the product, and 境酸碱度一般为中性和偏酸性。泥鳅对环境适应能力强，但也能为避开不利环境而逃逸。在天早水干或遇不利条件“休眠”期间，就会钻入泥层中，只要泥中稍有湿气，少量水分湿润皮肤，泥鳅便能维持生命。一旦条件好转，便会复出活动摄食。 2(呼吸 泥鳅对缺氧的耐受力很强，高水不易死亡，水体中溶氧低于0(16毫克,升时仍能存活，这是由于泥鳅不仅能用鳃呼吸，还能利用皮肤和肠进行呼吸。泥鳅肠壁很薄，具有丰富的血管网，能够进行气体交换，具辅助呼吸功能，所以又称为“肠呼吸”。当水中溶氧不足时，它便会浮出水面吞咽空气，在肠内进行气体交换(然后废气从肛门排出。人工养殖时，投饵摄食后泥鳅肠呼吸的次数会增加。据称，泥鳅耗氧量的1,3是由肠呼吸取得的。 3(温度 泥鳅生长的水温范围是13-30?，最适水温是24-27?。当水温降到5-lO?或升到30?以上时，泥鳅requirements for protection against handling product materials to use personnel management should make disclosure. 7.7.2 construction units should be made out to provide protective measures. If necessary, the handling should be in the operating instructions on the product provides for lifting the protection requirements in the process. 7.7.3 shipped to the secondary databases for temporary storage or delivered to the installation site the temporary storage of products, the ZHDB 306051-2003 storage management procedures should be in accordance with the requirements of section 2.4 of protection. 7.8 Installing and debugging before the change to the requirements of protection7.8.1 the construction units responsible for installation and commissioning during the transfer to product maintenance within the scope of construction and maintenance. 7.8.2 maintenance card protection equipment, construction units in accordance with the maintenance tab on the maintenance requirements and frequency of professional maintenance of the product, and 便潜入泥层下20-30厘米处，停止活动进行“休眠”。一旦水温达到适宜温度时，便又会复出活动摄食。 4(食性 泥鳅是偏好动物性饵料的杂食性鱼类。生长发育的不同阶段摄取食物的种类有所不同。幼鱼阶段，胃中的浮游动物，特别是桡足类明显较多。成鱼阶段，胃中的昆虫幼虫，特别是摇蚊幼虫明显高于幼鱼。泥鳅的食性很广，在泥鳅胃中的食物团里腐殖质、植物碎片、植物种子、水生动物的卵等的出现率最高，约占70,，其他如硅藻、绿藻、蓝藻、棵藻、黄藻、原生动物、枝角类、桡足类、轮虫等占30,。人工养殖中能摄食商品饵料。 泥鳅在一昼夜中有两个明显的摄食高峰，分别是7-10时和16-18时，而早晨5时左右是摄食低潮。 泥鳅与其他鱼龟类混养时常以其他鱼类的残饵为食，可称为池塘的“清洁工”。泥鳅肠道短小，对动物性饵料消化速度比植物性饵料快。泥鳅贪禽，如投喂动物性饵料时会因贪食过量，而影响肠呼吸，并产生requirements for protection against handling product materials to use personnel management should make disclosure. 7.7.2 construction units should be made out to provide protective measures. If necessary, the handling should be in the operating instructions on the product provides for lifting the protection requirements in the process. 7.7.3 shipped to the secondary databases for temporary storage or delivered to the installation site the temporary storage of products, the ZHDB 306051-2003 storage management procedures should be in accordance with the requirements of section 2.4 of protection. 7.8 Installing and debugging before the change to the requirements of protection7.8.1 the construction units responsible for installation and commissioning during the transfer to product maintenance within the scope of construction and maintenance. 7.8.2 maintenance card protection equipment, construction units in accordance with the maintenance tab on the maintenance requirements and frequency of professional maintenance of the product, and 毒害气体而胀死。当水温为15?时泥鳅的食欲增高;水温24~27?时最旺盛;水温30?以上时食欲减退，在泥鳅生殖时期食量比较大，雌鳅比雄鳅更大，以满足生殖时期卵黄积累和生殖活动的需要。 5(光照 泥鳅一般白天潜伏水底，傍晚后活动觅食，不喜强光。人工养殖时往往集中在遮光阴暗处，或是躲藏在巢穴之中。 6(生长 泥鳅生长快慢和饵料、饲养密度、水温、性别和发育时期有关，人工养殖中个体差异也很大。在自然状况下，刚孵出的苗体长约0(3厘米，1个月之后可达3厘米，半年后可长到6-8厘米，第二年年底可长成13厘米体长、15克左右的体重。最大的个体可达20厘米、100克体重。人工养殖时约经20天左右培育便可达3厘米的鳅苗，1足龄时可长成每公斤80~100尾的商品鳅。 requirements for protection against handling product materials to use personnel management should make disclosure. 7.7.2 construction units should be made out to provide protective measures. If necessary, the handling should be in the operating instructions on the product provides for lifting the protection requirements in the process. 7.7.3 shipped to the secondary databases for temporary storage or delivered to the installation site the temporary storage of products, the ZHDB 306051-2003 storage management procedures should be in accordance with the requirements of section 2.4 of protection. 7.8 Installing and debugging before the change to the requirements of protection7.8.1 the construction units responsible for installation and commissioning during the transfer to product maintenance within the scope of construction and maintenance. 7.8.2 maintenance card protection equipment, construction units in accordance with the maintenance tab on the maintenance requirements and frequency of professional maintenance of the product, and 7(繁殖 泥鳅一般1冬龄性成熟，属多次性产卵鱼类。长江流域泥鳅生殖季节在4月下旬，水温达18?以上时开始，直至8月份，产卵期较长，盛产期在5月下旬至6月下旬。每次产卵花时也长，一般4—7天时间才能排卵结束。 泥鳅怀卵量因个体大小而有差别，卵径约1毫米，吸水后膨胀达1.3毫米，一般怀卵8000粒左右，少的仅几百粒，多的达十几万粒。12-15厘米体长泥鳅怀卵约1万-1.5万粒;20厘米体长泥鳅怀卵达2(4万粒以上。体长9.4—11.5厘米雄性泥鳅精巢内含约6亿个精子。而雄泥鳅体长约达6厘米时便已性成熟。成熟个体中往往雌泥鳅比例大。 泥鳅常选择有清水流的浅滩，如水田、池沼、沟港等作为产卵场:发情时常有数尾雄泥鳅追逐一尾雌泥鳅，并不断用嘴吸吻雌鳅头、胸部位，最后由一尾雄鳅拦腰环绕挤压雌鳅，雌鳅经如此刺激便激发排卵，雄鳅排精。这一动作能反复多次。产卵活动往往在雨后、夜间或凌晨。受精卵具弱粘性，黄色半透明，可requirements for protection against handling product materials to use personnel management should make disclosure. 7.7.2 construction units should be made out to provide protective measures. If necessary, the handling should be in the operating instructions on the product provides for lifting the protection requirements in the process. 7.7.3 shipped to the secondary databases for temporary storage or delivered to the installation site the temporary storage of products, the ZHDB 306051-2003 storage management procedures should be in accordance with the requirements of section 2.4 of protection. 7.8 Installing and debugging before the change to the requirements of protection7.8.1 the construction units responsible for installation and commissioning during the transfer to product maintenance within the scope of construction and maintenance. 7.8.2 maintenance card protection equipment, construction units in accordance with the maintenance tab on the maintenance requirements and frequency of professional maintenance of the product, and 黏附在水草、石块上，一般在水温19-24?时经两天孵出鳅苗。 刚孵出的鳅苗约3.5毫米，身体透明呈“痘点”状，吻瑞具黏着器，附着在杂草和其他物体上。约经8小时，色素出现，体表渐转黑色、鳃丝在鳃盖外，成为外鳃。3天后卵黄囊接近消失，开始摄食生长、约经20多天，苗长15毫米，此时的形态与成鳅相似，呼吸功能也从鳃呼吸转为兼营肠呼吸功能了。 requirements for protection against handling product materials to use personnel management should make disclosure. 7.7.2 construction units should be made out to provide protective measures. If necessary, the handling should be in the operating instructions on the product provides for lifting the protection requirements in the process. 7.7.3 shipped to the secondary databases for temporary storage or delivered to the installation site the temporary storage of products, the ZHDB 306051-2003 storage management procedures should be in accordance with the requirements of section 2.4 of protection. 7.8 Installing and debugging before the change to the requirements of protection7.8.1 the construction units responsible for installation and commissioning during the transfer to product maintenance within the scope of construction and maintenance. 7.8.2 maintenance card protection equipment, construction units in accordance with the maintenance tab on the maintenance requirements and frequency of professional maintenance of the product, and