Abstract

The effect of water temperature on the timing of spawning and spat settlement of the Yesso scallop (Mizuhopecten (=Patinopecten) yessoensis Jay, 1857) in Minonosok Cove (Posyet Bay, Peter the Great Bay) has been studied based on the most complete dataset of observations for 1970–2011. The date of onset of spawning varied from May 1 to June 9 (within 40 days) and the onset of spat settlement varied from June 4 to July 5 (within 32 days). It has been found that the timing of spawning shifts to later dates due to the longer preceding cold periods with a greater accumulated sum and lower average values of below-zero temperatures, due to the short pre-spawning periods (from the date when the sea surface temperature (SST) reaches 0°C to May 1) with decreased sums and low average temperatures over these periods, as well as due to the decreased sums of temperatures in April. Later settlement dates were also recorded in the years with severe winter conditions. The onset of settlement shifts to a later date also in case of low average above-zero temperature in the pre-spawning period (correlation coefficient (R) = –0.46). Early settlement on collectors was observed in the years when SST reached 0°C on earlier dates in spring (at the Posyet Hydrometeorological Station). The higher the sum of above-zero temperatures was accumulated by May 1 and June 1, as well as in April and May, the earlier the scallop spat settled on collectors (R = –0.58, –0.60, –0.55, and –0.42, respectively). Prognostic equations are proposed to predict the dates of the onset of spawning and spat settlement with a lead time of 10 and 15 days, respectively; the equations are tested on the results of a correlation analysis. The accuracy of these predictions based on 10-year independent samples constitutes 70% for the spawning onset date and 60% for the spat settlement onset date.

中文翻译：

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水温对Minonosok湾（Posyet湾，彼得大帝湾，日本海）Yesso扇贝（Mizuhopecten yessoensis Jay，1857年）的产卵和吐落时间的影响

摘要

水温对虾夷扇贝（Mizuhopecten（= Patinopecten）yessoensis）产卵和卵沉降时间的影响。根据最完整的1970-2011年观测资料集，对Minonosok湾（Posyet湾，彼得大帝湾）的Jay（1857年）进行了研究。产卵的开始日期从5月1日到6月9日（40天以内）不等，而结算的开始时间从6月4日到7月5日（32天内）不等。已经发现，由于前产卵期短（从海域发生之日起），产卵时间的变化是由于较冷的前期较长，累积总和较大，而较低的零温度以下平均值较低，因此推迟到较晚的日期发生。地表温度（SST）到5月1日达到0°C），这期间的总和有所减少，平均温度较低，这也是由于4月温度的总和有所减少。在冬季条件恶劣的年份，也记录了较晚的定居日期。R）= –0.46）。在春季早些时候（在Posyet水文气象站）SST达到0°C的年份中，观测到收集者的早期沉降。到5月1日和6月1日以及4月和5月，高于零温度的总和累积得越多，扇贝吐口落在收集器上的时间就越早（R = –0.58，–0.60，–0.55和–0.42，分别）。提出了预后方程式来预测产卵和吐口定居的发生日期，前置时间分别为10天和15天。根据相关性分析的结果对方程进行测试。这些基于10年独立样本的预测的准确性在产卵开始日期占70％，在卵子沉降开始日期占60％。