Estimating the dynamics of spawning aggregations using biological and fisheries data
journal contribution
posted on 2023-05-19, 05:07authored byPunt, AE, Smith, DC, Haddon, M, Russell, S, Tuck, GN, Ryan, T
Acoustic surveys can provide accurate estimates of biomass at a particular location at a point in time, but provide a negatively biased estimate of the total spawning population unless the proportion of fish that are unavailable to the survey is accounted for. Changes to the ages and maturity stages of fish caught during the spawning season is evidence for turnover of fish during spawning and, along with information on relative abundance, provides a basis for estimating turnover rates. A model is therefore developed that tracks the numbers of males and females by age as they arrive on the spawning grounds, initiate spawning, complete spawning and leave the spawning grounds. This model can be used to determine the proportion of the spawning biomass on the spawning grounds over the spawning season. It is applied to data for blue grenadier, Macruronus novaezelandiae, off western Tasmania, Australia. The results can be used to estimate the average proportion of the population available to an acoustic survey, although this estimate is not likely to be very precise, owing to the high between-year variation in arrival times. However, the model provides a quantitative estimate of turnover rate that was previously not available, and is a rigorous basis for estimating turnover for stock assessment.
History
Publication title
Marine and Freshwater Research
Volume
67
Pagination
342-356
ISSN
1323-1650
Department/School
Institute for Marine and Antarctic Studies
Publisher
CSIRO Publishing
Place of publication
150 Oxford St, Po Box 1139, Collingwood, Australia, Victoria, 3066