turchini-barrensofgold-2018.pdf (765.65 kB)
Barrens of gold: gonad conditioning of an overabundant sea urchin
journal contribution
posted on 2018-01-01, 00:00 authored by Cassandra G Pert, Stephen E Swearer, Symon Dworjanyn, Nina Kriegisch, Giovanni Turchini, David FrancisDavid Francis, Tim DempsterOvergrazing by the overabundant native purple urchin Heliocidaris erythrogramma has caused kelp-dominated reefs to shift to urchin barrens throughout southeastern Australia. These areas are characterised by low kelp abundance, low biodiversity and high urchin densities. As purple urchin gonads are a delicacy in many countries, commercial harvest from barrens could aid kelp recovery. However, the lack of macroalgae in these habitats, driven by high urchin densities, results in urchins with small, poor-quality roe that is commercially undesirable. To overcome this, we assessed whether urchin gonad quantity and quality could be improved with access to high-quality feed and optimal environmental conditions, a process known as ‘gonad conditioning’. Specifically, we (1) surveyed the quality of urchins from barrens and kelp sites in Port Phillip Bay, Australia, over 18 mo and (2) tested if gonad conditioning was effective on urchins from barrens during and after the harvest season. Field surveys revealed considerable variation in gonad size across sites, habitats and collection periods (mean gonad index range: 3 to 12%). Gonad conditioning with the best diet increased urchin gonad size by up to 2.8 times during the harvest season. Moreover, gonads of conditioned urchins from one barren were 3 times brighter in colour and contained lower concentrations of arsenic than wild urchins. In contrast, gonad conditioning at 22°C after the harvest season was ineffective. Our results show that targeted in-season harvest from barrens and subsequent gonad conditioning produces roe of commercial quality, promoting the use of urchin fisheries as a tool for managing urchin barrens.
History
Journal
Aquaculture environment interactionsVolume
10Pagination
345 - 361Publisher
Inter-ResearchLocation
Oldendorf, GermanyPublisher DOI
Link to full text
ISSN
1869-215XeISSN
1869-7534Language
engPublication classification
C Journal article; C1 Refereed article in a scholarly journalCopyright notice
2018, The AuthorsUsage metrics
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Keywords
Science & TechnologyLife Sciences & BiomedicineFisheriesMarine & Freshwater BiologyRoe enhancementHeliocidaris erythrogrammaAquacultureUrchin barrenTemperaturePurple urchinNEW-SOUTH-WALESSTRONGYLOCENTROTUS-DROEBACHIENSISEVECHINUS-CHLOROTICUSHELIOCIDARIS-ERYTHROGRAMMAPARACENTROTUS-LIVIDUSCENTROSTEPHANUS-RODGERSIIREPRODUCTIVE IMPAIRMENTEMBRYONIC-DEVELOPMENTCHRONIC EXPOSUREEcology
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