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Updated: Jun 23, 2025

Measuring the Structure, Composition, and Change of Underwater Environments with Large-area Imaging
Published on: April 18, 2025
Can juvenile supply predict future abundance of large-bodied reef fishes?
Shaun K Wilson1, Martial Depczynski2, Christopher J Fulton2
1Australian Institute of Marine Science, Indian Ocean Marine Research Centre, Crawley, Western Australia, Australia; Oceans Institute, Indian Ocean Marine Research Centre, The University of Western Australia, Crawley, Western Australia, Australia; Marine Science Program, Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia, Australia.
Abstract:
The extent to which juvenile abundance can predict future populations of lethrinids at Ningaloo Reef was assessed using size frequency data collected over 13 consecutive years. Annual abundance of juvenile lethrinids (<5 cm TL) was highest in northern Ningaloo during La Niña years, when seawater is warmer and oceanic currents stronger. Juvenile lethrinid abundance explained 35% of the variance in 1-2 year-old Lethrinus nebulosus abundance the following year, a steeper relationship in the north suggesting greater survival of juveniles. Juvenile lethrinid abundance was also positively correlated to abundance of 1-2 year-old L. atkinsoni in the southern region of Ningaloo. Abundance of juvenile lethrinids were however poor predictors of L. nebulosus and L. atkinsoni older than 2 years of age. Post settlement processes likely weaken the link between juvenile supply and abundance of lethrinids >2 years old making it difficult to accurately quantify the overall size of future lethrinid populations.
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