%0 Journal Article
%T Spawning ecology of the anchovy Engraulis japonicus in the spawning ground of the Southern Shandong Peninsulaｊ. Spawning habits and embryonic developmental characteristics of the anchovy
%A WAN Rui-Jing
%A ZHAO Xian-Yong
%A WEI Hao
%J Acta Zoologica Sinica
%D 2008
%I 
%X The investigations on the spawning ground of the Southern Shandong Peninsula by water mass drift experiments were carried out from May to July during 2000每2004. Spawning habits and embryonic development characteristics of anchovy are studied from these observations. It is shown that duration for the germ cells fully developed from spawning to hatch are different under different temperature. The durations are 42每44 hours when the water temperature is 21.78⊥每22.68⊥ ㄗaveraged 22.05⊥ㄘand 50每52 hours while the water temperature is 17.05⊥每18.88⊥ ㄗaveraged 17.90⊥ㄘat the surface layer. In the upper mixed layer, the durations for fully development are 44每46 hours and 50每54 hours under the water temperature of 21.26⊥每22.05⊥ ㄗaveraged 21.70⊥ㄘ and 17.02⊥每17.90⊥ ㄗaveraged 17.50⊥ㄘ respectively. While in the thermocline, the water temperature are 16.22⊥每21.26⊥ ㄗaveraged 18.70⊥ㄘand 14.42⊥每17.02⊥ ㄗaveraged 15.72⊥ㄘ, the durations are 46每48 hours and 68每72 hours respectively. One-way ANOVA showed that the anchovy embryonic development duration observed from in situ data was not significantly different from that calculated academic (P > 0.05), which indicates that both the in situ observation and academic estimation methods applied in the present study are reliable. Water temperature in the spawning ground in late June of 2003 is 1.80⊥每3.80⊥ lower than that of 2002. It makes the duration of anchovy embryonic development 8每24 hours longer. Developmental threshold temperature of anchovy germ cells is 10.26⊥ and the sum of effective temperature is 423.1 h﹞⊥. At the spawning season, adult anchovy produce new eggs from 19ㄩ00 in the evening till next 5ㄩ00 in the early morning. The spawning duration will last 10 hours. At night time from 21ㄩ00 to next 2ㄩ00 am is the peak spawn time. The adult anchovy mainly spawn in the thermocline [Acta Zoologica Sinica 54ㄗ6ㄘㄩ988每997, 2008].
%K Shandong Peninsula
%K Spawning ground
%K Anchovy Engraulis japonicus
%K Embryonic development
%K Developmental threshold temperature
%K Sum of effective temperature
%K Spawning time and layer
%U http://www.currentzoology.org/paperdetail.asp?id=11035