Effects of substrate colour and fouling organisms on the recruitment of oysters and barnacles:results from field experiment
Adequate larvae supply and substrates suitable for larvae settlement are two key factors for successful oyster reef restoration.Oyster settlement and recruitment are influenced by a variety of physiological and external environmental factors,including larval physiological status,temperature,pH,light,hydrology,substrate texture,direction,angle,shape,color and transparency,biofilm,fouling organisms,and the presence of conspecifics.It is highly important to understand the settlement and recruitment of oysters and barnacles for oyster reef restoration.Previous studies have examined the effects of substrate types,new and old shells and substrate size on settlement and recruitment of Crassostrea sikamen.This study examined the effects of substrate color(experiment Ⅰ:white and black tiles)and fouling organisms(experiment Ⅱ:Crassostrea ariakensis,C.sikamea,oyster shell and barnacle)on natural recruits of Crassostrea sikamen and barnacle through field experiments at a natural oyster reef of Jiantiao Bay,Zhejiang Province.The experiment Ⅰ compared the surface temperature and oyster recruits between the black tiles and white tiles with five replicates through field observations.The results of one-way ANOVA showed that the surface temperature on the black tiles was significantly higher than that on the white tiles(q=20.104,P＜0.05);the maximum temperature difference between these two tiles reached 4.0 ℃,with an average difference of(2.5±0.1)℃.Substrate color significantly influenced natural oyster recruits.The white tiles had significantly greater oyster recruits than the black tiles at 15 and 30 d after the initiation of the experiment(P＜0.05),but the difference in recruits disappeared at 45 d(P＞0.05).The color of substrate did not affect natural recruits of barnacle(P＞0.05).The experiment Ⅱ examined the differences on the natural recruitment of oysters and barnacles among experimental tiles settled by living Crassostrea ariakensis,C.sikamea,oyster shell,living barnacle alone.The results indicated that the presence of live oysters(C.ariakensis or C.sikamea)or oyster shells sometimes did not affect or significantly decreased natural oyster recruits.It was consistent with that the presence of barnacles significantly reduced natural oyster recruits.In contrast,the presence of live oysters,oyster shells and barnacles did not affect natural barnacle recruits on the experimental substrates(P＞0.05).The experimental studies found that oyster recruits on the white tiles was significantly higher than those on the black tiles,while barnacle recruits had no difference between these two colored substrates.The presence of live Crassostrea sikamea,live C.ariakensis,and oyster shells did not facilitate the natural recruits of oysters,while barnacles actually inhibited oyster settlement and recruitment.It was found that the fouling organisms had no effect on settlement and recruitment of barnacles.The study concludes that substrates with light color and clean surface without fouling organisms is recommended for oyster reef restoration projects,and the reef should be constructed away from places and times with high barnacle recruitment.
万方数据
维普
