Saving Coral Reefs with Biosecure, Zero Water Exchange Aquaculture

Dr Bill McGraw, Aquaculture and Environmental Scientist www.newaquatechpanama.com

Coral reefs support approximately 25 percent of all known marine species. As one of the most complex ecosystems on the planet, coral reefs are home to more than 4,000 species of fish, 700 species of coral, and 1000s of other plants and animals. Globally corals have diminished primarily due to increasing water temperatures with periodic, intense El Niño events. However, equally destructive are nutrient and chemical inputs from agriculture, deforestation, untreated domestic wastewater, and unlimited water exchange from aquaculture.

There is currently a worldwide reduction in coral reefs in terms of total area and the number of species. The largest barrier reef in world is estimated to have sustained damage at the rate of at least 50% of the total. In other areas corals have been reduced in abundance by 50% such as in the Caribbean Sea near Panama. Over the past 30 years, coral mortality was reported regularly in other areas of coral reefs on both sides of Panama. The more recent major El Niño event, of 2015-2016 that has caused extensive coral bleaching at the pristine Secas Islands, 23 miles off the pacific coast of Panama, has been well documented (https://docs.wixstatic.com/ugd/98c15b_f8bb90aa56424b7fbb3cfdbd05f350b2.pdf).

Little can be done regarding decreasing the number and severity of El Niño events as the only possible explanation for their existence is associated with periodic solar events such as sun spots and coronal mass ejections. Although the so called global warming has been linked to bleaching of corals, El Niño and anthropomorphic inputs are still more damaging.

In any case, increasing temperatures may benefit the growth of sponges which are intricately linked to coral reefs (https://thefishsite.com/articles/how-sponges-adapt-to-climate-change). Also, corals from shallow water that have been exposed to periodic warmer water with the changing tides can repopulate deeper waters where corals, adapted to more steady temperatures, have succumbed to high water temperatures from episodic El Niño events (https://thefishsite.com/articles/surviving-el-nino-corals-at-coiba-island). Corals can also adapt to El Niño events by exchanging existing algal symbionts with new varieties which can survive higher temperatures.

Near sensitive coral reef habitats where there is human development, deforestation will likely continue and agriculture will increase with the need for more food with exploding subtropical and tropical populations. Farming will likely stay dependent on synthetic fertilizers due to the nitrogen poor soils associated with these areas and the lack of development of more sustainable and more environmentally friendly practices such as permaculture. Although waste water treatment is improving in areas such as Panama, eutrophication continues unabated. These inputs will contribute to more nitrogen, phosphorous and sedimentation in rivers and estuaries, resulting in increased bacteria and algae growth, negatively affecting coral development.

Excess nutrient inputs create an imbalance of the ecology between fish and corals in a reef ecosystem. Regular interactions between different trophic levels help to maintain a balance between coral growth and the associated predators and prey in the coral reef habitat. The reduction of marine life that grazes on the types of algae that grow on corals and compete with them for space and survival decreases coral growth and development. Maintaining an adequate population of coral grazers through regulation of fisheries, while decreasing the nutrient inputs to the coral reef habitat is essential to the survival of corals.

Although some nutrient inputs into waterways are difficult to manage, there is an awesome opportunity for decreasing nutrient input to coral reef areas with the implementation of biosecure, zero water exchange aquaculture. Low water exchange, efficient and profitable tilapia systems have been implemented in areas of the US with great success (https://thefishsite.com/articles/key-factors-in-creating-the-largest-tilapia-ras-in-the-world). Offshore aquaculture, away from the sensitive ecology of coral areas is also being conducted and proven to be ecologically and economically sound. Moreover, there exist other strategies for increasing the sustainability and decreasing the environmental impact of different types of aquaculture (https://thefishsite.com/articles/the-many-sides-of-sustainability-in-aquaculture).

Shrimp aquaculture is the biggest culprit to habitat destruction in coastal areas. Making this worse is the fact that every decade there is a $45 billion loss to shrimp farms from viral disease. Viruses are transferred from one farm to another through water exchange. Infected shrimp tissue released during water exchange into coastal areas can enter a different farm with water intake during daily water exchange to maintain water quality and keep shrimp healthy. Through this process nutrients and sediments are released into coastal areas resulting in habitat destruction (https://thefishsite.com/articles/new-technology-for-shrimp-farming-in-panama).

It will be too late to act when the coral reefs are gone. However, major shrimp producers have realized the benefit of limited water exchange and are implementing indoor, multiple species aquaculture with increased efficiencies. This new technology has a positive impact on the environment with all organic waste sustainably incorporated into the much needed poor soils of subtropical and tropical regions where coral reefs are located.

More information and pictures can be found at www.newaquatechpanama.com

Dr Bill McGraw is a native of Pennsylvania, USA. After having competed two degrees in science from his home state, he went on to finish a Ph.D. in aquaculture in 2000 at Auburn University, and a two year post doctorate fellowship at Harbor Branch Oceanographic Institute of Florida, in 2002. Although he spent most of his time working with commercial aquaculture start-ups in South Africa, Australia, New Zealand and Panama from 2003 onward, he found time to publish over 50 articles in peer reviewed scientific journals, magazines and websites. His research interests range from the study of coral reefs in relation to El Niño and the destruction of coral reef habitat, to zero water exchange aquaculture production systems that incorporate new species and polyculture, utilizing all nutrient inputs. Dr Bill set world records in terms of zero water exchange shrimp production systems, he was the first in the world to grow the Pacific Spiny Lobster (Panuliris gracilis) in a closed aquaculture system at 5 kg/m³ , and the first to document the sea hair, Dolabella auricularia, as the fastest growing aquatic animal known. He is currently very busy with finishing writing a book on mercury toxicity, building a zero water exchange, commercial, multiple species shrimp aquaculture system in Panama, and treating people for chronic disease using Rife technology.

Internet Sources:

1. Surviving El Nino, Corals at Coiba Island https://thefishsite.com/articles/surviving-el-nino-corals-at-coiba-island
2. http://www.vox.com/2015/8/17/9164499/el-nino-2015
3. http://www.stri.si.edu/english/about_stri/headline_news/news/article.php?id=1938
4. https://www.sciencenews.org/article/heat-waves-are-roasting-reefs-some-corals-may-be-resilient
5. http://smithsonianscience.si.edu/2013/08/qa-katie-cramer-on-the-long-term-human-impact-on-coral-reefs-in-carribbean-panama/
6. http://edition.cnn.com/2016/11/28/asia/great-barrier-reef-coral-death/
7. http://smithsonianscience.si.edu/2015/08/study-reveals-agriculture-and-fishing-cause-coral-reef-decline/
8. http://smithsonianscience.si.edu/2014/11/33141/
9. http://edition.cnn.com/2016/10/14/us/barrier-reef-obit-trnd/
10. http://www.coibanationalpark.com/
11. https://en.wikipedia.org/wiki/Coiba
12. http://panamainfo.com/en/destinations/santa-catalina-and-coiba-island
13. www.stri.si.edu/sites/darwin_initiative/PDFs/Guzman_etal_lobster_2008.pdf
14. spo.nmfs.noaa.gov/mfr761-2/mfr761-23.pdf
15. http://www.sciencedirect.com/science/article/pii/B9780444513885500187

References

1. Brown BE (1997) Coral bleaching: causes and consequences. Coral Reefs 16:S129-S138
2. Eakin CM, Liu G, Gomez AM, De La Cour JL, Heron SF, Skirving WJ, Geiger EF, Tirak KV & Strong AE (2016) Global Coral Bleaching 2014-2017: Status and an Appeal for Observations. Reef Encounter 46: 20-26
3. Hoegh-Guldberg O (1999) Coral bleaching, climate change and the future of the world’s coral reefs. Marine and Freshwater Research 50: 839-866
4. Jokiel PL & Coles SL (1990) Response of Hawaiian and other Indo-Pacific reef corals to elevated temperatures. Coral Reefs 8:155-162.
5. Lesser (2011) Coral bleaching: causes and mechanisms. In: Coral reefs: An ecosystem in transition, Dubinsky Z, Stambler N (eds), Springer, pp. 405-420
6. Rowher F, Youle M (2010) Coral Reefs in the Microbial Seas. Plaid Press.
7. Sapp J (1999) What is natural? Coral Reef Crisis, Oxford University Press, Oxford
8. Smithsonian Tropical Research Institute: System Shock: El Niño Tests Coral Survival Limits. http://www.stri.si.edu/english/about_stri/headline_news/news/article.php?id=1938 (October 12, 2015)
9. Veron JEN, Hoegh-Guldberg O, Lenton TM, Lough JM, Obura DO, Pearce-Kelly P, Sheppard CRC, Spalding M, Stafford-Smith MG, Rogers AD (2009). The coral reef crisis: The critical importance of <350 ppm CO2. Mar Poll Bull 58: 1428-1436.

Help us break-even with our minimal operating costs to make sure this resource does not go away. Join fellow readers in supporting our work through 2018.

or support us on patreon.com

• Running community building projects in 174 countries
• Engaging student ambassadors in over 50 universities
• Forming strategic alliances and partnerships with over 200 professional organizations
• Publishing over 500 authors, photographers, and researchers
• Sponsoring dozens of beach and community clean-ups
• Providing free scientific resources for educators
• Promoting over 20 tailored conservation job postings per week- totaling over 1000 opportunities per year
• Inspiring and educating our readers through rich imagery, engaging content, and a compelling conservation message
• We do all of the above FOR FREE, because we care about the future

Find the latest articles on SEVENSEAS Media here.

Want to get in touch with questions or a submission? Contact us here.

This piece was edited and posted onto SEVENSEAS Media by Giacomo Abrusci