大潮差下浅海养殖围网防纠缠技术试验研究

大潮差海况条件会对养殖围网设施敷设产生较大影响,会发生网衣堆积严重、易纠缠、贴底网衣离底、网衣撕裂等生产安全事故,因此,网衣防纠缠技术研究非常重要。研究制作了小尺寸围网模型,采用装配横纲、沉力纲、浮力纲的方法设计3种不同的围网网衣沉降和升浮技术方案,进行模拟涨潮、落潮的网衣堆积试验研究。选取网衣堆积较明显的水位(水位分别降低30~60 cm)进行分析。结果显示:水位降低30 cm时,方案C,即采用浮沉力纵向向下递增分布的方法,网衣堆积高度最大,堆积系数最小;当水位降低分别为40 cm、50 cm、60 cm时,也得出同样的结果。研究表明:网衣堆积高度越大,堆积系数越小,网衣能够在更多层面堆积,发生纠缠的可能性越小。实际应用效果证明方案C适合在大潮差海域应用。

Experimental study on anti-entanglement technology of purse seine for shallow sea culture in spring tide range

Spring tide has a great influence on installation of purse seine aquaculture facilities, including serious netting accumulation, entanglement, bottom netting getting away from the base, netting tear, etc.Therefore, it is very important to study the anti-entanglement technology of netting.A small-scale purse seine model was made and 3 different schemes for settlement and lift of netting were designed (i.e., assembled horizontal line, sinking force lines and buoyancy lines) to simulate the netting accumulation in flood and ebb tides.The water level (water level was reduced by 30-60 cm) of obvious netting accumulation was selected for analysis.The results showed that when the water level was reduced by 30 cm, because the method of longitudinal increasing downward of buoyancy and sinking force was used in Scheme C, the netting reached the maximum accumulation height and the minimum accumulation coefficient.When the water level was reduced by 40 cm, 50 cm or 60 cm, the same results were obtained.The study showed that the higher the netting was accumulated, the smaller the accumulation coefficient was, and the netting might accumulate in more layers, resulting in the less possibility of entanglement.The actual application result proves that Scheme C is suitable to be used in spring tide waters.