The Effects of Multiple Fin Amputations on Rates of Fin Regeneration in Goldfish, Carassius Auratus (Linnaeus)

Goldfish, Carassius auratus (Linnaeus), were used in the study of rates of regeneration in all possible combinations of caudal, dorsal, left pectoral, and right pectoral fin amputations. The purpose of this study was to ascertain the effects of multiple injuries on rates of regeneration, to determine rates of regeneration in different fins, to test the hypothesis that rates of regeneration decrease from the proximal to the distal areas of a fin, and to determine the presence or absence of morphogenetic gradients in fin regeneration. In almost all cases, no significant differences in total regeneration were found to occur when the total regeneration in a particular single cut was compared to the total regeneration which occurred in the same cut on a multiple cut fish. Analysis of variance indicated that significant differences between total regeneration in different fins occurred during the ten week test period. Duncan\u27s multiple range test indicated significant differences occurred between the total regeneration in the caudal fin cuts and the total regeneration in all other cuts in the one through ten week periods. In only the one, two and eight week periods were significant differences found to have occurred between the dorsal and either the left pectoral or the right pectoral cuts. In all other test periods no significant differences were found to have occurred among these cuts. Graphs of average total regeneration showed that in each of the four fins, rates of regeneration decreased from the proximal to the distal areas of the fin. Slopes of these curves indicated that regeneration in the caudal fin had not yet reached completion while restoration of amputated tissue in the dorsal and pectoral fins was completed or was nearing completion. Consideration was given to a possible controlling mechanism for varying regeneration rates within the same fins and in different fins. It was suggested that a dual hormonal-nervous system mechanism involving varying numbers of receptor sites within the same fin and among different fins was responsible. The available information seems to indicate that a morphogenetic gradient within an entire fin or occurring from one portion of the body to another and affecting fin regeneration does not exist