Using Cox Regression Model with Time Dependent Explanatory Variable for Survival Analysis of Common Sole, Solea solea L.


PAKISTAN JOURNAL OF ZOOLOGY, vol.43, no.3, pp.497-504, 2011 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 43 Issue: 3
  • Publication Date: 2011
  • Page Numbers: pp.497-504


In this study, Cox regression models for fixed and time dependent explanatory variables were studied for Solea solea under culture conditions. The data of wild common sole (Solea solea) was obtained from fish population maintained under culture conditions. Common soles were caught by trawling and trammel nets between March and April, 2007 around the Urla, Izmir Bay. At the beginning of the study 270 common soles obtained by both fishing methods were subjected to a five-day dark period and antibiotic treatment (furozolidon, 100 gmL(-1),60 min.): A total of 128 common soles were adapted to culture conditions for ten days, and then human chorionic gonadotropin (HCG) injection (250-500 IU/kg fish), luteinizing hormone releasing hormone analog (LH-RHa) injection (30 mu and LH-RHa pellet hormone (30 mu were administered to the fish. When the results of Cox regression analysis were applied with forward selection method in the case of fixed and time dependent common variables, there was no significant difference in means of hazard rates with respect to the application type. In the present study, the Cox regression model was applied to a real cluster of data and interprets the results obtained from wild common sole in culture conditions.