The seasonal, lunar and diurnal changes in schooling of jack mackerel were examined using log-book
information collected from an industrial fishery off the east coast of Tasmania between 1985 and 1989.
School size increased significantly from spring to autumn. The ratio between surface and subsurface
schools encountered by the fishery also changed seasonally. Surface schools predominate during summer,
whereas subsurface schools become more frequent during autumn. The fishery was predominantly a day
fishery and no lunar effects on catch rates or fishing intensity were detected. Catches mainly comprised
jack mackerel, although redbait (Emmelichthys nitidus Richardson) and blue mackerel (Scomber australasicus
Cuvier) were a significant by-catch. In summer, schools were almost exclusively composed of jack mackerel,
but in other seasons mixed schools were found. Data presented, together with evidence from other sources,
suggest that the availability of schools to the fishery may be closely related to the availability of feed.
GRSS Summer Schools in 2020 [Education]
