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Harrison HB, Drane L, Berumen ML, Cresswell BJ, Evans RD, Galbraith GF, Srinivasan M, Taylor BM, Williamson DH, Jones GP. Ageing of juvenile coral grouper ( Plectropomus maculatus) reveals year-round spawning and recruitment: implications for seasonal closures. Proc Biol Sci 2023; 290:20230584. [PMID: 37339745 DOI: 10.1098/rspb.2023.0584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/30/2023] [Indexed: 06/22/2023] Open
Abstract
Temporal patterns in spawning and juvenile recruitment can have major effects on population size and the demographic structure of coral reef fishes. For harvested species, these patterns are crucial in determining stock size and optimizing management strategies such as seasonal closures. For the commercially important coral grouper (Plectropomus spp.) on the Great Barrier Reef, histological studies indicate peak spawning around the summer new moons. Here we examine the timing of spawning activity for P. maculatus in the southern Great Barrier Reef by deriving age in days for 761 juvenile fish collected between 2007 and 2022, and back-calculating settlement and spawning dates. Age-length relationships were used to estimate spawning and settlement times for a further 1002 juveniles collected over this period. Unexpectedly, our findings indicate year-round spawning activity generates distinct recruitment cohorts that span several weeks to months. Peak spawning varied between years with no clear association with environmental cues, and little to no alignment with existing seasonal fisheries closures around the new moon. Given the variability and uncertainty in peak spawning times, this fishery may benefit from additional and longer seasonal closures, or alternative fisheries management strategies, to maximize the recruitment contribution from periods of greatest reproductive success.
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Affiliation(s)
- H B Harrison
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
- Marine Biology and Aquaculture, College of Science & Engineering, James Cook University, Townsville 4811, Queensland, Australia
| | - L Drane
- Marine Biology and Aquaculture, College of Science & Engineering, James Cook University, Townsville 4811, Queensland, Australia
| | - M L Berumen
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia
| | - B J Cresswell
- Marine Biology and Aquaculture, College of Science & Engineering, James Cook University, Townsville 4811, Queensland, Australia
- Commonwealth Scientific and Industrial Research Organisation, Townsville 4811, Queensland, Australia
| | - R D Evans
- Department of Biodiversity Conservation and Attractions, 17 Dick Perry Ave, Kensington 6151, Australia
- Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - G F Galbraith
- Marine Biology and Aquaculture, College of Science & Engineering, James Cook University, Townsville 4811, Queensland, Australia
- Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), James Cook University, Townsville 4811, Queensland, Australia
| | - M Srinivasan
- Marine Biology and Aquaculture, College of Science & Engineering, James Cook University, Townsville 4811, Queensland, Australia
- Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), James Cook University, Townsville 4811, Queensland, Australia
| | - B M Taylor
- University of Guam Marine Laboratory and UOG Sea Grant, 303 University Drive, UOG Station, Mangilao, Guam 96923, USA
| | - D H Williamson
- Great Barrier Reef Marine Park Authority, Townsville 4810, Queensland, Australia
| | - G P Jones
- Marine Biology and Aquaculture, College of Science & Engineering, James Cook University, Townsville 4811, Queensland, Australia
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