Significant variation in spawning frequency of common coral trout, Plectropomus leopardus, on the Great Barrier Reef

Carter, Alex, Carton, Guy, Russ, Garry, Tobin, Andrew, and Williams, Ashley (2011) Significant variation in spawning frequency of common coral trout, Plectropomus leopardus, on the Great Barrier Reef. In: Abstracts from the 48th Annual Conference of the Australian Marine Sciences Association. p. 35. From: AMSA 2011: 48th Annual Conference of the Australian Marine Sciences Association, 3-7 July 2011, Fremantle, WA, Australia.

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Abstract

Spawning frequency estimates are essential for understanding the reproductive biology of species with indeterminate fecundity, and are vital when calculating annual fecundity. However, spawning frequency is not well quantified for tropical fishes, particularly exploited tropical fish. We investigated the relationship between spawning frequency with maternal size and age for the common coral trout Plectropomus leopardus, the most commercially important finfish on the Great Barrier Reef (GBR). Four GBR regions were sampled (Lizard Island, Townsville, Mackay, Storm Cay), over four years (1998 – 2001), and compared between reefs open and closed to fishing. Spawning frequency was determined histologically using the post-ovulatory follicle (POF) method. Of the 2481 coral trout ovaries histologically classed as mature, 23.7% contained POFs <24 h old, indicating coral trout spawn approximately every 4.22 days. Logistic regression revealed there was no effect of maternal size or age on spawning frequency. Spawning frequency decreased significantly with increasing latitude on the GBR. Townsville and Lizard Island's mature females spawned every 2.91 and 3.96 days, respectively, compared with every 16.17 and 20.25 days, respectively, for Mackay and Storm Cay's females. Spawning frequency also varied with year, peaking in all regions in 1998 or 1999. Marine reserve status had a significant but varied effect on spawning frequency. Storm Cay and Lizard Island's females were spawning almost twice as often on fished than protected reefs. In contrast, Townsville's protected females were spawning twice as often in protected reefs, and in Mackay's fished reefs no female spawners were found over the 4 years of sampling while protected females spawned every 13 days. Decreased spawning activity in the southern GBR and extended spawning during all lunar phases in the central and northern GBR suggests a regional approach to the management of coral trout reproduction, particularly the timing and duration of spawning closures, is appropriate. The results also highlight the importance of multi-year studies to determine the extent of annual variation in reproductive parameters, and the need for further research into the region-specific response in spawning frequency to no-take marine reserve zoning.

Item ID: 39942
Item Type: Conference Item (Abstract / Summary)
ISBN: 978-0-9587185-6-1
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Date Deposited: 09 Sep 2015 01:22
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050205 Environmental Management @ 50%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050206 Environmental Monitoring @ 50%
SEO Codes: 96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960507 Ecosystem Assessment and Management of Marine Environments @ 50%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 50%
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