2002_Ziegler,_Frusher,_Johnson_&_Gardner_MFR_A.pdf (218.73 kB)
Catchability of the southern rock lobster Jasus edwardsii. I. Effects of sex, season and catch history
journal contribution
posted on 2023-05-16, 13:48 authored by Philippe ZieglerPhilippe Ziegler, Stewart FrusherStewart Frusher, Craig JohnsonCraig Johnson, Caleb GardnerCaleb GardnerSeasonal variation in catchability of the southern rock lobster Jasus edwardsii, was estimated in a scientific reserve in south-east Tasmania by comparing estimates of lobster density based on direct visual observations underwater with concomitant estimates from trapping surveys. Underwater density estimates of undersized and legal-sized male and female lobsters >80 mm carapace length, did not change significantly over the 14-month study period, with the exception of undersized males (≤110 mm carapace length). Sex ratios remained constant at approximately 1:1. In marked contrast, catch rates of males and females and the sex ratio of trapped lobsters varied strongly with season, implying that catchability varies seasonally and with sex. Catchability of males and females was highest in early summer and lowest in winter. Impact of capture on subsequent catchability appeared to be weak, since the ratios of tagged animals in the population observed underwater generally reflected recapture rates of tagged animals in trap catches. Recapture rates increased with size and were higher for medium-sized and large males than for similar-sized females. However, for each particular sex-size group, recapture rates remained relatively constant throughout the study period.
History
Publication title
Marine and Freshwater ResearchVolume
53Issue
8Pagination
1143-1148ISSN
1323-1650Department/School
Institute for Marine and Antarctic StudiesPublisher
CSIRO PublishingPlace of publication
AustraliaRepository Status
- Restricted