In the realm of environmental management, particularly in combating invasive species, it is critical to embrace innovative approaches and involve a diverse array of stakeholders. Traditional methods may be familiar, but they are not always the most effective or efficient solutions for contemporary challenges. This article explores the pressing issue of invasive marine species, specifically rogue urchins, underscoring the need for new technologies and collaborative efforts among communities, citizen scientists, governments, academics, policymakers, and industries. We look at Tasmania, California, and New Zealand, we aim to highlight the potential benefits and challenges of adopting advanced technological solutions over conventional methods. This includes addressing the economic, environmental, and social implications of these choices and proposing a path forward that leverages modern technology to restore and protect marine ecosystems.
Case Study 1: Tasmania - Centrostephanus rodgersii In Tasmania, the long-spined sea urchin (Centrostephanus rodgersii) poses a significant threat to marine ecosystems, particularly kelp forests, which have seen a dramatic 95% decline over the last 30 years [1]. The loss of kelp forests has disrupted the entire marine food web, affecting species such as rock lobsters and abalone. Efforts to manage these urchins have primarily included hiring divers to manually remove them. The process is labour-intensive and costly, with estimates for clearing a single bay, Fortescue Bay, approaching one million dollars .
Project Idea: Our proposal seeks to leverage underwater drones equipped with specialised tools to cull Centrostephanus rodgersii populations. This approach not only targets inaccessible areas but also ensures comprehensive removal of urchins regardless of size. The underwater drones will conduct culling and harvesting sessions to assess efficacy and environmental impact. Collaboration with local researchers and environmental organisations will ensure data sharing and best practices.
Case Study 2: California - Strongylocentrotus purpuratus In California, the purple sea urchin (Strongylocentrotus purpuratus) has devastated kelp forests, crucial habitats for numerous marine species [6]. The loss of kelp forests has led to a decline in biodiversity and negatively impacted fisheries and tourism, with economic losses estimated in the millions of dollars [7]. Volunteer divers have stepped in to help manage the urchin populations, a wonderful display of community.
The traditional methods of control in California include manual removal by volunteer divers and the establishment of marine protected areas (MPAs) to facilitate kelp forest recovery [9]. Organisations such as Reef Check California and Giant Giant Kelp Restoration Project coordinate volunteer efforts to manually remove urchins, while local fisheries sometimes provide incentives for urchin removal [10]. Companies like Ocean Rainforest work with local divers to harvest urchins, which are then processed for various uses including the culinary market [11]. These efforts have shown some success, with localised kelp recovery observed in areas with intensive urchin removal [12].
Case Study 3: New Zealand - Integrated Management Approach New Zealand faces similar challenges with urchin barrens in its northeastern waters. Fisheries New Zealand has proposed an integrated management approach that includes a new special permit under the Fisheries Act to allow for the harvest, culling, or translocation of urchins for habitat restoration [13]. This proactive stance aims to mitigate the spread of urchin barrens and restore marine ecosystems, setting a precedent for innovative management practices [14].New Zealand also has the Sustainable Food and Fibre Futures Fund with funding for innovative projects that have sustainable benefits to New Zealand, from under NZ$100,000 to over NZ$1,000,000.
Traditional methods in New Zealand involve both manual removal by divers and commercial harvesting. Companies such as Southern Clams Ltd. and Moana New Zealand have engaged in harvesting sea urchins for their roe, providing economic incentives for divers to remove urchins [15]. This approach has been partially effective, with some improvements in kelp forest health following urchin removal, but the scale and logistics of manual culling remain challenging [16].
Challenges and Opportunities The traditional method of hiring divers to manually remove urchins is costly and inefficient. Estimates for clearing a single bay , Fortescue Bay in Tasmania approach one million dollars, with significant operational constraints [17]. In contrast, our underwater drones, costing $5,000 each, offer a more economical, efficient, and safer alternative. These inexpensive underwater drones can operate in deeper waters, longer hours, and even at night when urchins can be more active. Divers could operate these drones as a way to supplement their income. We would welcome any divers in Tasmania to contact us with this opportunity.
This selective commercial harvesting can result in sustained or even increased urchin populations, as the smaller urchins continue to consume kelp and grow [18]. Allowing urchins to eat the kelp ensures they are of higher commercial value, but it directly conflicts with the goal of kelp forest restoration. Studies on the quality of urchins from barren areas versus those from kelp-rich environments indicate that urchins fed on kelp are preferred for commercial purposes due to their better taste and higher market value (Hereu et al., 2019) Research has shown that selective harvesting of larger urchins can lead to sustained population levels of smaller urchins, which continue to graze on kelp and inhibit forest recovery (Johnson et al., 2011)
Kelp forests are crucial marine habitats that support a wide range of marine life. Overgrazing by urchins can lead to the formation of urchin barrens, where kelp and other marine vegetation are decimated. This has significant ecological consequences, including loss of biodiversity and disruption of the marine food web.
Effective urchin population control requires the removal of urchins of all sizes, not just the larger, commercially valuable ones. Leaving smaller urchins in place allows the population to rebound, leading to continuous pressure on kelp forests and preventing their recovery. The ecological importance of kelp forests and the detrimental impact of urchin overgrazing are well-documented, highlighting the need for comprehensive management strategies that address the entire urchin population (Ling et al., 2009)
The need for innovative solutions in managing invasive marine species is evident. Embracing new technologies, such as underwater drones, can provide effective and scalable solutions to these challenges. By fostering collaboration and openness to innovation, we can better protect and restore our marine ecosystems.
Down Deep Drones founder John Griffiths has been granted a scientific research permit to test his urchin culling and harvesting tools on an underwater drone in Tasmania. We will let you know of our progress in these blogs and perhaps look out for our Kickstarter campaign to be launched soon!
References
1. Ling, S. D., et al. "Overfishing Reduces Resilience of Kelp Beds to Climate-Driven Catastrophic Phase Shift." Proceedings of the National Academy of Sciences, vol. 106, no. 52, 2009, pp. 22341–22345.
2. Johnson, C. R., et al. "Climate Change Cascades: Shifts in Oceanography, Species' Ranges and Subtidal Marine Community Dynamics in Eastern Tasmania." Journal of Experimental Marine Biology and Ecology, vol. 400, no. 1-2, 2011, pp. 17-32.
3. "Managing the Long-Spined Sea Urchin in Tasmania." Institute for Marine and Antarctic Studies, University of Tasmania.
4. "Abalone Industry Reinvestment Fund." Tasmanian Government, Department of Primary Industries, Parks, Water and Environment.
5. "Tasmanian Sea Urchin Industry." Sea Urchin Harvest Company. https://seaurchinharvest.com.au
6. "California's Kelp Forests: Urchin Crisis and Restoration Efforts." California Department of Fish and Wildlife.
7. Rogers-Bennett, L., and Catton, C. A. "Marine Heat Wave and Multiple Stressors Tip Bull Kelp to Sea Urchin Barrens." Scientific Reports, vol. 9, no. 1, 2019, pp. 15050.
8. "Purple Sea Urchin Management." Reef Check California.
9. "Urchin Barrens and Kelp Forest Restoration." Monterey Bay National Marine Sanctuary.
10. "Volunteer Divers in California." Reef Check California.
11. "Sea Urchin Harvest and Processing." Ocean Rainforest.
12. "Kelp Forest Recovery in California." California Department of Fish and Wildlife.
13. "Urchin Barrens in Northeastern New Zealand." Fisheries New Zealand.
14. Shears, N. T., and Babcock, R. C. "Marine Reserves Demonstrate Top-Down Control of Community Structure on Temperate Reefs." Oecologia, vol. 132, no. 1, 2002, pp. 131-142.
15. "Commercial Sea Urchin Harvesting in New Zealand." Southern Clams Ltd.
16. "Integrated Management of Sea Urchins." Fisheries New Zealand.
17. "Economic Analysis of Sea Urchin Removal." Tasmanian Aquaculture and Fisheries Institute.
18. "Challenges in Marine Pest Management." Australian Government Department of Agriculture, Water and the Environment.
Our Kickstarter Campaign!
A quick update. Not long now 'till the launch of our Kickstarter project - we hope the project will be approved and then we will start to promote it.
Overgrazing urchins could be culled or harvested using our tools that attach to QYSEA underwater drones.
John has made a few urchin culling tools to put on QYSEA FIFISH underwater drones. We have two QYSEA FIFISH V-Evos with grabber claws and John has made a special motor to power his tools in conjunction with the grabber actuator.
With the motor to power or propel the tools, John then set about designing tools to cull or harvest the urchins.
Here is John making a CAD file for the Axe Head.
Most of the time we are able to 3D print the CAD files, and test the size and shape of the tools. If they work out, we then send them off to be machined. We have a very competent machinist that is quick, capable and affordable. We have worked with them on over twenty different jobs and are always happy. Any small issues are remedied immediately.
Sometimes we make small changes after receiving the machined parts. Most of the time we are able to use them.
Repeating Spear
Rotary Cutting Blade with Saw Tooth (teeth)
Propelled Spear with Drill Bit
We have other urchin culling tools on the way and will add the videos to this blog soon!
Here are our extra wide grabber claws, and we are attaching a basket underneath them to harvest the urchins. These may help divers to harvest in deeper waters and maximise their time.
Anyone interested in finding out more information on the project can reach alicia@downdeepdrones.com .
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