细点圆趾蟹肉酶解肽螯合锌工艺的优化

为了优化蟹肉酶解肽的锌螯合工艺,以细点圆趾蟹肉为原料,制得蟹肉酶解物,通过单因素试验,考察酶解物与硫酸锌的质量比、pH、反应时间、酶解物浓度、反应温度对锌修饰蟹肉酶解肽的影响,采用正交试验优化蟹肉酶解肽的锌修饰工艺。结果表明,在酶解物与硫酸锌的质量比2∶1、pH值6.5、时间60 min、酶解物浓度5%、温度55℃条件下,酶解肽-锌的螯合率为91.52%,螯合物得率为25.83%,该工艺条件下酶解肽与锌的螯合率和螯合物得率均较高。本研究结果为新型生物态锌的研制、细点圆趾蟹的高值化利用提供了依据。     

东海细点圆趾蟹的生物学特性

根据1998—2000年在东海虾蟹资源调查和渔业生产监测调查中周年采集的1576只细点圆趾蟹样品，开展了基础生物学研究，结果表明，东海细点圆趾蟹的渔获群体甲长分布范围为26～95mm，甲宽为32～120mm，体重为5～410g，雄蟹个体平均大于雌蟹；春季雌蟹生长不明显，而雄蟹则生长迅速，2—6月平均增长率达38．7％；周年雌蟹略多于雄蟹，性比约为1：0．88，繁殖盛期为3—5月，不同个体怀卵量在6．8～75．8万粒之间，最小抱卵个体的甲长为46mm，甲宽为60mm，体重为59g，多数抱卵个体的甲长为50～60mm，甲宽为65～80mm，体重为80～115g。周年摄食强烈，半胃、饱胃率多数时间在50％～60％以上，其中冬春季摄食强度大于夏秋季．     

Evaluation of artificial and natural baits for the pot fishery of the sand crab Ovalipes punctatus (De Haan, 1833)

We compared the luring effectiveness of artificial bait made from fish waste with natural baits in pots targeting the sand crab Ovalipes punctatus in the East China Sea. Bait types used were fish (mackerel), minced fish (heads of greenling) and two artificial baits made mostly from fish waste and starch. The first two need frozen storage but artificial bait does not. Three fishing operations were conducted in May 2010 and in each forty pots (10/treatment) were fastened along a bottom line. Results for the three operations had catch data for 30 pots/treatment. The number of crabs captured was 496, of which 206 (41.5%) were caught in pots containing fish, 116 (23.4%) in those with minced bait, and 93 (18.8%) and 81(16.3%) in pots baited with the two artificial baits, respectively. Fish was significantly more attractive than minced bait and artificial baits, but no differences were detected between the other baits. Natural baits disappeared almost entirely by the time of hauling, with only 1% of the fish and 5.3% of the minced bait remaining; artificial bait remained almost intact (96.3–100%). The artificial bait catch was approximately half of that of fish bait, but it only contained 30% fish waste. Furthermore, if catch returns are calculated according to the bait's fish content their efficiency seemed higher, ranging from 88 to 100 crabs/kg of fish waste vs only 69 crabs/kg of fish.     

东海细点圆趾蟹数量分布的研究

本文依据1998年5月(春)、8月(夏)、11月(秋)和1999年2月(冬)在东海26°00’-33°00’N,127°00’E以西海域的蟹类资源调查资料,分析了东海细点圆趾蟹(Ovalipes punctatus)数量分布特征。结果表明:春、夏、秋和冬季调查海域细点圆趾蟹平均资源密度重量和个体数分别为65.00 kg·km-2、2076 ind·km-2,43.71 kg·km-2、395 ind·km-2,26.27 kg·km-2、643 ind·km-2和0.36 kg·km-2、7 ind·km-2。冬春季,东海北部近海细点圆趾蟹重量占蟹类总重量的一半以上,出现率和优势度远远高于其它水域,以产卵群体为主,是目前细点圆趾蟹最大的生产渔场。东海南部近海80-120m水深和北部外海80 m以深海域,各有一个细点圆趾蟹的高数量分布区。细点圆趾蟹的生产旺汛在春季的3-6月。夏季由于该种渔获个体规格和经济价值较高,加上有一定的资源密度,也是较好的捕捞季节。该种虽然能够适应广泛的温度和盐度,但具有明显的温水种特征,在东海北部近海又具有较低盐度的分布趋向性。