Oral Presentation AFSS/NZFSS Joint Conference 2019

Move it or lose it: Movement history influences growth of freshwater fish (#182)

Joshua Barrow 1 , John Morrongiello 1 , Jian Yen 1 , John Koehn 2
  1. The University of Melbourne, Melbourne, Victoria, Australia
  2. Arthur Rylah Institute, Melbourne, Victoria, Australia

The decision to move or to stay has significant fitness implications for individuals in partially migrating species. Partial migration occurs when some individuals within a population move, while the remainder of the population remain resident. There may be positive or negative consequences for individuals that decide to move or stay, including improved access to food resources, the ability to escape from poor conditions, and increased risk of predation or capture. We used otoliths (ear bones) to explore the growth history of individual golden perch (Macquaria ambigua), a partially migrating species native to the Murray-Darling Basin in eastern Australia. We compared a series of mixed effects models, each containing one movement predictor that represented a plausible hypothesis relating to the effects of movement on growth. We found that growth differed between resident and migrant fish, particularly in the early life. We also explored the variation in growth of migrant and resident fish at each age, and found that variation in migrant fish growth remained stable across ages, while there was greater variation in the growth of young resident fish, which then declined for older individuals. This research addresses a key gap in our understanding of how movement influences growth.