Harvest Patterns of New-Guinea (Crocodylus-Novaeguineae) and Saltwater (Crocodylus-Porosus) Crocodiles in Papua-New-Guinea, 1969-1980

摘要

The harvest patterns of Crocodylus novaeguineae and C. porosus in Papua New Guinea are discussedrnon the basis of an analysis of 1969-1980 harvest data. No trends in numerical harvest were found forrneither species, although some trends were detected in the frequency of harvest composition for thernformer species. The proportion of juvenile and adult size classes in harvests of C. novaeguineae showsrna respective increase and decrease in the Western Province (southern population), while the proportionrnof subadult size classes decreased in the two Sepik Provinces (northern population). A cyclic harvestrnpattern was observed in C. novaeguineae juvenile size classes from the Western Province, but suchrnpatterns were not detected in harvest size classes for that species elsewhere. No trends or cyclic patternsrnwere detected in size classes of C. porosus harvests. Harvest compositions strongly differed amongrnpopulations for most within-year intra-specific comparisons for each species. Differences amongrnpopulations were largely attributable to selective harvesting and marketing strategies that variedrnbetween harvest areas.rnSex ratios of juvenile and subadult C. novaeguineae differed significantly among populations.rnA female bias was present in the northern population sample, while a 1 : 1 ratio existed for pooledrnsubdistricts in the southern population. However, subdistricts of the latter each differed significantlyrnfrom a 1 : 1 ratio, with a male bias found in the Lake Murray subdistrict and a female bias occurringrnin the Middle Fly subdistrict. Limited data showed a 0.6: 1 ma1e:female sex ratio for C. porosusrnin south-western Papua New Guinea.rnDespite being better protected by existing legislation with respect to adult size classes, C. porosusrnpopulations experienced far higher harvest mortality rates than C. novaeguineae populations.