Adriana Verges1,2, Chanelle Webster1, Cayne Layton3, Peter Steinberg1, Dane Wilmott4, Robert Chewying5, Ryan Morris6, Simon Rowe7, Maria Byrne8, Greg Finn9, Bill Barker4, Ezequiel Marzinelli8
1University of New South Wales, Australia - 2Sydney Institute of Marine Science, Australia - 3University of Tasmania, Australia - 4Nature Coast Marine Group, Australia - 5South Coast Aboriginal Fishing Rights Group, Australia - 6Sea Urchin Harvest, Australia - 7OceanWatch, Australia - 8University of Sydney, Australia - 9Pacific Urchin, Australia
Kelp forests and sea urchins are ecologically, economically and culturally valuable globally. In eastern Australia, however, sea urchins are an under-utilised resource, and their increasing numbers threaten kelp forests and the viability of the urchin fishery itself because urchin roe quality decreases dramatically once kelp declines and extensive urchin “barrens” form. Working in collaboration with Traditional Owners, fishers, government agencies, and conservationists, here we aimed to shift an unproductive urchin barren (no kelp; low-quality urchins), into a mosaic of productive kelp and urchin habitat. Using a mosaic system, a total of 11 tonnes of the longspined sea urchin (Centrostephanus rodgersii) were harvested by local fishers in replicate transect bands (20 m width) from a one-hectare site (depth range 6-12m) in southern New South Wales, Australia across two years. After urchin roe was extracted, urchin waste products were converted into soil fertiliser by a local seafood waste recycling company. Benthic habitat, fish biodiversity and abundance of rock lobster and abalone at the harvest site were compared before and after urchin harvesting and contrasted with three reference kelp sites and three control urchin barrens. Urchin gonad quality was also compared across all sites before and after harvest. Kelp recovery of two dominant species (Ecklonia radiata and Phyllospora comosa) was recorded in the urchin collection site 18 months after the first harvest, but only at the shallower depths. Marketable urchin products were obtained from 67% of all urchin harvested, although no top-grade roe was produced. Granularity of urchin gonads improved in the urchin harvested site. Abalone and rock lobster were mostly only observed in the kelp reference sites, with small numbers of abalone also being recorded in the revegetated urchin collection band post-harvest. These findings provide preliminary evidence that an enhanced sea urchin fishery can drive synergistic environmental, economic, social and cultural benefits to coastal communities in eastern Australia.
Biography
Adriana Vergés is a Professor in marine ecology at UNSW Sydney and the Sydney Institute of Marine Science (Australia). Her research focuses on climate change impacts and integrates rigorous science with novel ways of regenerating marine ecosystems. Her work is well known for involving the public hands-on in marine restoration and for collaborating with public artists in innovative participatory art-meets-science exhibitions and festivals to raise awareness about marine ecosystems.