Rhythmic swimming of the isopod Exosphaeroma obtusum (Dana)     

A. A. Fincham 《新西兰海洋与淡水研究杂志》2013,47(4):655-662

The tidal swimming rhythm of the New Zealand rocky shore isopod Exosphaeroma obtusum (Dana) is described. Peak swimming was on the ebb tide about 2.5 h after high water; the peak in the dark period was 6–8 times greater in amplitude than the daytime peak. Positive thigmotaxis was shown at all other times. The rhythm period in continuous darkness (free‐running period) was greater than tidal periodicity, and there was a semi‐lunar swimming pattern with peaks at the first and third quarters of the moon. Rheotropic experiments showed that changes in water flow did not initiate the swimming rhythm. The work was compared with the infaunal species Pseudaega punctala and the northern Eurydice pulchra. It was concluded that infaunal species rely more on endogenous control of the swimming rhythm because of their isolation, when buried, from exogenous Zeitgeber.  相似文献   

The potential food poisoning hazard of Vibrio parahaemolyticus in New Zealand Pacific oysters     

G. C. Fletcher 《新西兰海洋与淡水研究杂志》2013,47(4):495-505

The level of Vibrio parahaemolyticus was generally very low in Pacific oysters sampled from 4 New Zealand oyster farms between November 1982 and May 1983. Of the 149 samples collected, only one was found to contain greater than the 1000 organisms g^‐1regarded as the maximum allowable by international standards (International Commission on Microbiological Specifications for Foods 1982: Micro‐organisms in Foods, Vol. 2. Academic Press, New York). V. parahaemolyticus was detected in 57% of the oyster samples, but 95% of these contained less than 10 organisms g^‐1. Maximum levels appeared to coincide with high water temperatures at the farm sites. Chilling, freezing, and depuration reduced V. parahaemolyticus numbers in oysters after harvest. However, holding at ambient temperatures (19–25°C) resulted in up to a 35‐fold increase in organism numbers with a maximum after one day. The food poisoning hazard from V. parahaemolyticus in New Zealand‐grown Pacific oysters thus appears to be minimal. Recommendations are made to keep harvested shellfish cool and to chill them as soon as practical.  相似文献   

牡蛎壳人工礁对多毛纲底栖动物群落结构的影响     

徐勤增  许强  张立斌  张涛  杨红生 《海洋与湖沼》2013,44(4):1056-1061

采用功能群及多元统计方法, 对山东荣成俚岛湾牡蛎壳人工增殖礁礁区与毗连非礁区底质中多毛纲动物群落结构进行对比研究, 评估了牡蛎壳人工礁对多毛纲底栖动物群落结构的影响。结果表明, 人工礁区与非礁区共采集19科39种多毛纲动物, 按食性分为植食性、沉积食性和肉食性三大功能群。礁区肉食性多毛纲动物栖息密度高于非礁区, 可能与人工礁礁体底栖多毛纲动物引起的边缘效应有关。多维尺度分析MDS、相似度分析ANOSIM以及多因素方差分析(PERMANOVA)结果表明, 礁区同非礁区多毛纲动物群落结构差异不显著, 这可能与牡蛎壳人工礁单体体积较小, 对近底层水体及底质理化环境的影响较小有关。综上所述, 牡蛎壳人工礁在较小时间尺度内(1—2年)对底栖环境无显著影响。  相似文献   

Changes in the contents of ATP and its related breakdown compounds in various tissues of oyster during frozen storage     

WANG Qi XUE Changhu LI Zhaojie FU Xueyan XU Jie XUE Yong 《中国海洋大学学报(英文版)》2007,6(4):407-412

The changes in the contents of adenosine 5’-triphosphate (ATP) and its related breakdown compounds were investigated in the adductor muscle, mantle, gill and body trunk of oyster (Crassostrea gigas) during frozen storage at -20℃ and -30℃ and compared with that of the fresh oyster. The investigation was performed using an HPLC system. Different extents of ATP decomposi- tion were found in various tissues frozen at the two temperatures. The K, K’ and A.E.C values were calculated as the chemical fresh- ness indices. Considering the results of sensory evaluation, the A.E.C. value in body trunk at -20℃ and -30℃ could be used as the best freshness index for frozen oyster.  相似文献   

微塑料对近江牡蛎免疫力的影响          下载免费PDF全文

牟红莉  王瑞旋  王俊  林小植  王江勇 《海洋科学》2023,47(9):53-60

为探究微塑料对牡蛎免疫力的影响,该研究对近江牡蛎(平均壳长:6.6cm)采用壳内推注的方式注入不同浓度的聚苯乙烯微塑料(0.05、0.5、5 mg·L^–1,以无菌生理盐水为稀释液),分别胁迫24 h、48 h和72 h后,检测分析牡蛎鳃组织的免疫指标(碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)、丙二醛(MDA)、过氧化氢酶(CAT)、一氧化氮合成酶(NOS)和乙酰胆碱酯酶(AChE))的变化。结果显示,在胁迫24 h后,微塑料浓度对AKP的活力有显著影响(P<0.05)。SOD、AKP和结构型一氧化氮合成酶的活性呈现明显的先升后降的趋势。在胁迫48 h后,微塑料浓度上升导致A-chE活力显著下降(P<0.05), CAT、SOD和AKP呈现先升后降的趋势。在胁迫72 h后,微塑料浓度的升高, AKP和AChE的活力呈现先降后升的趋势,而SOD、CAT和诱导型一氧化氮合成酶的活力与之呈现相反的趋势,显示先升后降的趋势。随时间和浓度的增长, MDA处于一直上升的趋势。以上结果表明,微塑料可使牡蛎产生免疫应激反应,且胁迫时间越长,牡蛎免疫应激反应越剧烈。  相似文献