The Research Of The Effect Of Abalone Ranching In The Artificial Reef Of Laoshan Bay

Artificial reefs， in the form of rocks and logs have been used for thousands ofyears as an enhancement device by attracting fishes. More recently， theirapplications have varied widely， including: aquaculture production; nutrientremoval; recreational diving and tourism; coastal protection; surfing reefs; and，habitat protection. It has been postulated that artificial reef deployment combined withabalone stock enhancement may achieve the dual purpose of habitat and stockimprovement and be a cost-effective method of increasing production of targetedspecies. The objective of this thesis was to test these claims at artificial reef ofLaoShan Bay by manipulating a habitat within a net cage， by placement ofartificial reefs， and utilising stock enhancement techniques to seed a site withabalone(Haliotis discus hannai Ino).Thereby， we could monitor growth andsurvival of abalone and ambient environment factors.The results of the survey: annual variation in ocean temperature is3.1-25.1℃，salinity is31.6-34.1， they are accordance of the requirements of growth andsurvival of abalone; According to the Sea Water Quality Standard，transparency，pH， DO， CODMn， BOD5， all kinds of nutritive salts， oils and sulfide are allconform to Grade II water quality standards， and Pollution index of them are lessthan1in the investigating period; All the heavy metals in the water meet therequirements of Seawater aquaculture water quality， and Pollution index of heavymetals are less than1in the investigating period； heavy metal， oil and sulfide inthe sediment meet the requirements of Grade I standards of Marine SedimentQuality，and Pollution index of them are less than1in the investigating period;Scope of benthic algae biomass is290.2g/m2-463.5g/m2，and the types of biggerbiomass are Gelidium divaricatum， Gelidium amansii， Sargasso Sea， Corallina pilulifera， Undaria pinnatifida and Enteromorphalinza in the feedingpeak of abalone， while wakame and sargasso are like eating algae of abalone.The aspects of abalone， the mean growth rate were63.5μm/d for individuals of15months. The fastest growing stage was up to78.7μm/d， and the lowest growingstage was up to13.6μm/d. Compared with other abalone breeding data， growthspeed was up to higher level， and conformed to the requirements of the business.Mean survival was66.03%. Death mainly concentrated in the initial stage ofexperiment， after the survival rate can reach more than90%. Survival rate isslightly lower than intertidal abalone cage culture data， higher than the bottomculture data on proliferation. And we obtain the equation relationship between thewater temperature and the growth rates of shell length: y=-0.0009x3+0.0188x2+0.2271x-2.0025， R2=0.9471，y=growth rate of shell length （mm/month），x=water temperature.