{"refrec":{"BRefID":5967,"RR":"<b>Mayfield, S.; Branch, G.M.</b> (2000). Interrelations among rock lobsters, sea urchins and juvenile abalone: implications for community management. <i>Can. J. Fish. Aquat. Sci. 57(11)</i>: 2175-2185","BEntID":5967,"PublicFlag":1,"CheckedFlag":0,"wosflag":1,"vabbflag":0,"RefStringPartII":". <i>Can. J. Fish. Aquat. Sci. 57(11)</i>: 2175-2185","DocTypID":8,"DocType":"Journal article","MarineFlag":1,"FreshFlag":0,"BrackishFlag":0,"TerrestrialFlag":0,"Authorstring":"Mayfield, S.; Branch, G.M.","OrigTitleTranslFlag":0,"Authorstringtrunc":"Mayfield, S.; Branch, G.M.","Englishabstract":"Field and laboratory experiments demonstrate that juveniles of South African abalone <i>(Haliotis midae)</i> depend vitally on the protection from predation that they gain from living concealed beneath Cape urchins <i>(Parechinus angulosus)</i>. Recent reports suggest that rock lobsters <i>(Jasus lalandii)</i> have increased substantially in the region where the commercial abalone fishery is centered. This increase has been blamed for a recorded collapse of urchin populations and dramatic reductions in the numbers of juvenile abalone. We verified the substantial increase in rock lobster abundance there. Surveys covering 200 km of coastline showed that densities of urchins were negatively correlated with those of large lobsters (>68 mm carapace length) and that densities of juvenile abalone were positively correlated with those of urchins. The indirect negative effects of rock lobsters on juvenile abalone clearly pose a major threat to the abalone industry, already under stress from poaching. Quantification of the relationship between juvenile abalone and urchins and between urchins and rock lobsters allows a forecast of the magnitude of lobster harvesting necessary to reduce them to a level at which urchins may recover and sustain juvenile abalone. The complex interactions involved emphasize the importance of an ecosystem approach for the management of these stocks.","AbstractOtherLang":"Des expériences menées en laboratoire et sur le terrain ont montré que les juvéniles de l'ormeau <i>(Haliotis midae)</i> d' Afrique du Sud dépendent de façon vitale de la protection contre la prédation que leur assurent les oursins du Cap <i>(Parechinus angulosus)</i>, sous lesquels ils vivent cachés. Des rapports récents indiquent que la population de langoustes <i>(Jasus lalandii)</i> a fortement augmenté dans la zone où se concentre la peche commerciale de l' ormeau. On attribue à cette augmentation l'effondrement des populations d'oursins et la baisse spectaculaire du nombre des ormeaux juvéniles qui ont été observés. Nos travaux ont confirmé la forte augmentation du nombre de langoustes. Nos relevés, qui couvraient 200 km de littoral, ont montré que les densités d'oursins étaient négativement corrélées a celles des grosses langoustes (>68 mm de longueur de carapace) et que les densités d'ormeaux juvéniles étaient positivement corrélées a celles des oursins. Les effets négatifs indirects des langoustes sur les ormeaux juvéniles constituent àl'évidence une grave menace pour la peche de l'ormeau, secteur qui souffre déjà des activités de braconnage. La quantification de la relation entre les ormeaux juvéniles et les oursins et entre les oursins et les langoustes permet de prédire le volume de prélèvement de langoustes qui serait nécessaire pour réduire leurs populations à un niveau permettant aux oursins et de se rétablir et de soutenir les ormeaux juvéniles. Les interactions complexes qui entrent en jeu font ressortir l'importance d'une approche écosystémique pour la gestion de ces stocks.","BibLvlCode":"AS","StandardTitle":"Interrelations among rock lobsters, sea urchins and juvenile abalone: implications for community management","OrigTitleLangCode":"en","OrigTitleLangCodeExtended":"eng","OrigTitleLangID":15,"DateLastModified":{"date":"2024-12-10 01:33:17.368041","timezone_type":1,"timezone":"+01:00"},"UserAccessRight":null,"UserAccID":null,"AuthorKeywords":null,"OtherDescriptors":null,"Notes":null,"AnaPub":2000,"MonPub":null,"DateUpdate":"2021-11-25","DateCreate":"2001-02-06","SecASFANote":null,"ConfID":null,"PeerRev":1,"VlizCoreFlag":1,"WoScode":"WOS:000165451000001","VABBcode":null,"OpenAcc":0},"refs":null,"anarec":{"AnaID":5967,"PubliDate":2000,"Pagination":"2175-2185","XtraPublOfAnaID":null,"ISBN":null,"Volume":"57","Issue":"11","BRefMon":null,"BRefMonRR":null,"BRefXtra":null,"BRefXtraRR":null,"SerBRefID":42535,"SerRR":"Canadian Journal of Fisheries and Aquatic Sciences = Journal canadien des sciences halieutiques et aquatiques. National Research Council Canada: Ottawa.  ISSN 0706-652X; e-ISSN 1205-7533","StandardTitleSer":"Canadian Journal of Fisheries and Aquatic Sciences = Journal canadien des sciences halieutiques et aquatiques","ISSN":"0706-652X","AbbrevSer":"Can. J. Fish. Aquat. 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