Experimental Study On Enhancemental Reef Of Octopus

With the reason of excessive fishing intensity and offshore environment pollution etc,the fishery resources are now suffering from lots of questions. The questions including severely decling fishery resources,depravation of fishery water,degradation and lose of habitat fo fishes,worsening of resource composing and frame,lag of fishery management have threaten the sustainnable development of fishery resources. Artificial reef are considered as effective approach to improve water environment and restore fishery resources by most fishery developed countries. And they are one of the main mearures optimizing the environment in farming fishery.Surrounding the subject of enhancing and protecting the resource of octopus,this paper studies the biology and resource status of octopus,the attracting theories of artificial reefs,the attractive effects of artificial reef models with different shapes and materials on Octopus ocellatus and Octopus variabilis and enhancement practice of octopus spawning reefs.This paper is diveded into six chapters according to the theories and application in practice. The content of the two chapters in front of this paper emphasizes on the study of octopus biology and foundation theories of artificial reef,the third and fourth chapters are about the experimental research of artificial reef models'attractive effects on Octopus ocellatus and Octopus variabilis,the last two chapters are the enhancement practice of octopus spawning reefs and discussion on the resource enhancement of octopus.In order to enhance the resource of octopus,firstly we should know its biology characters and ecological habits in detail. In the first chapter this paper summarizes the modal characters,life habits,propagating habits,the fishery and resources of Octopus ocellatus and Octopus variabilis,which supplies the basal data for the octopus resource enhancement of artificial reefs.For constructing artificial reefs,we should study the reaction of fishes to the reefs and find the mutual relationship between them fistly. The second chapter emphasizes on the study of attracting theories of artificial reefs,and analyses the effect on biologic and abiological environment when the reefs are put in the sea,which supplies the theoretic foundation for the resource enhancement of artificial reefs.In the third chapter,The behavioral response of Octopus ocellatus to three PVC matetial artificial reef models with different shapes and three tubular artificial reef models with different materials are studied in a flume. The attractive effects of the reefs on Octopus ocellatus are analysed. The results show that Octopus ocellatus have a higher distribution in the corner of the flume when there are no reef model. When the three shapes of PVC matetial reef models are put in,each attractive effect of them is obvious,the cubical reef model has the highest rate. For each shape the attractive rates of the apertured reef model is always higher than the imperforate. The attractive effects are obvious when the three tubular reef models with different materials are put in,among them the earthenware pipe has the highest attractive rate. The attractive effects of the superposed reef models are better than the singles distinctly,thereinto,the superposed earthenware pipe has the highest attractive rate of 39.3%.Chapter4,which as a complementarity and extension to last chapter,is about the experimental research of artificial reef models'attractive effects on Octopus variabilis. The behavioral response of Octopus variabilis to three PVC matetial artificial reef models with different shapes,two tubular artificial reef models with different materials and the behavior reaction under three light intensity ranges are studied in a flume. The attractive effects of the reefs on Octopus variabilis are analysed. The results show that Octopus variabilis have a higher distribution in the corner of the flume when there are no reef model. When the three shapes of PVC matetial reef models are put in,each attractive effect of them is obvious,the cubical reef model has the highest rate of 29.8%. The attractive effects are obvious when two tubular reef models with different materials are put in,the earthenware pipe has a higher attractive rate whether the model reefs are single or superposed. Under the light intensity range of 0～10lx,30～75lx and 150～250lx,the attractive effects of PVC superposed reef models are 39.3%,54.6% and 60.6%,each of them are lower than the attractive effects of earthenware pipe superposed reef(the rates are 54%,68.3% and 69.8%).The research shows that Octopus variabilis has strong territorial behavior during the experiment,which may influence the attractive effects of the artificial reef models,we analysed this at the end of the chapter.Basing on the research results of artificial reef models'attractive effects on two octopuses,we design several types spawning reefs of octopus according to breeding behavior habits and deploy the reefs in sea area for multiplication. In the last chapter of this paper,in order to enhancing and protecting the resource of octopus,we discuss on the design of new spawning reefs of octopus,the construction of kelp bed and artificial reef protecting areas etc. We provide available reference to multiplication and sustainable using of octopus stocks.