Estimating the natural mortality rate of saucer scallops (Ylistrum balloti) on the Queensland east coast from tag-recaptures

Saucer scallops ( Ylistrum balloti ) were tagged and released on four occasions inside two areas closed to fishing (Hervey Bay A, HBA; Yeppoon B, YB) the Queensland (Australia) east coast their subsequent recaptures over following months used measure instantaneous rate of natural mortality M ). A total 13,295 526 recaptured 15 month-long experiment (May 2018 August 2019). Three statistical approaches applied experimental design analysis tagging data, based 1) Brownie model, 2) a modified version 3) binomial logistic regression model recaptures. Estimates much higher for that at liberty summer compared those winter months, possibly indicating seasonal variation. The parameter estimates indicated proportion differed significantly with lunar phase recapture, scallop size class, number days interaction between days-at-liberty closure. All three was in HBA YB. Mean whole fishery, derived by averaging from both closures, ranged minimum 1.461 year –1 1.501 1.548 (variable recapture rate) 1.594 (fixed model. all than previous estimate published 40 years ago possible reasons increase are discussed. • Temporal spatial variation saucer tag-recaptures. Multidecadal ), Logistic models tag-recaptures can quantify