Reef Ramblings

27th July 2012

At the time of writing the UK is going through a period of very warm weather so it’s a good time to remind you about the danger that overheating can present to your reef tank. At this time of year reef aquaria can often reach potentially dangerous temperatures, bringing with it two distinct problems: heat induced coral bleaching and depleted oxygen levels.

Saltwater has a lower capacity for carrying dissolved oxygen than freshwater, as temperatures increase this carrying capacity reduces, in a reef with poor gas exchange the level of oxygen in the water can easily drop low enough for animals such as fishes and mobile invertebrates to asphyxiate.

I’d suggest checking that all pumps are working properly and efficiently and making provision for increasing your water movement in case of a prolonged period of hot weather. Making sure that the surface of the water is sufficiently agitated will both enhance gas exchange and aid temperature control via evaporative cooling. I’m currently recommending around a centimetre of “wave height” on the surface of the water, you’ll find that this will also enhance the effect of glitter lines, especially in an aquarium lit with fluorescent lamps.

Although you can mitigate the effects of high temperature induced oxygen depletion by increasing gas exchange, this will only go part way to helping corals to survive. This additional water movement can greatly enhance your corals chances of survival at higher temperatures and may be all that’s needed in some reefs, but ultimately you need to control the upper temperature reached in your aquarium.
It’s unfortunate that the cost of cooling a reef can often be as great, if not greater, than the cost of lighting it. Some reefs may need some form of cooling for the best part of the year owing to the way they’re lit. Your choice of methods of temperature control includes: refrigerant based chillers, evaporative cooling chillers, fans, air conditioners, and extractor fans.

Refrigerant based chillers and evaporative cooling chillers are the most expensive options.

Air conditioners are also expensive but they do have the bonus of controlling room temperature, which you and your family may well appreciate (it may also be a selling point to ”the significant other”, who may well have objected to the purchase of that expensive aquarium chiller!).

Extractor fans are useful to a degree but may make little difference once the room temperature is the same as outside.

Fans can be usefully employed to blow along the surface of the water to promote evaporative cooling, they’re cheap but do remember to take care in their placement as the last thing you want is a mains fan ending up in the aquarium! If possible choose a low voltage fan for safety.

Fans can also be extremely useful with enclosed aquariums and may improve how the tank runs on a daily basis, rather than just at times of high temperature, by improving gas exchange at the surface.

Don’t be tempted to turn aquarium heaters down or off as this will have no influence on water temperature during a warm period, indeed it can be detrimental to your reef when normal temperatures resume if you forget to turn them back on; if you see that a heater is turning on when your tank is running at an elevated temperature it is faulty and needs to be replaced.

Tim Hayes

Midland Reefs

©2012

20 July 2012

Healthy coral.

The past week or so has seen an interesting discussion about the future of the reefs in the online pages of the New York Times.

It started off on July12th with an op-ed piece from Roger Bradbury, an ecologist doing research in resource management at Australian National University, entitled ‘A World Without Coral Reefs’ that painted a very bleak picture of the future of the reefs, a view with which, to a certain extent, I concur.

This was followed up by two articles in the ‘Dot Earth’ section of the online New York Times, on July 14^th ‘Reefs in the Anthropocene – Zombie Ecology?’ and on July 16^th ‘More on Coral Reefs and Resilience or Ruination’ both by Andrew C. Revkin.

These articles are well worth the attention of reefkeepers everywhere, laying out as they do, the future of the environment that forms the basis of our hobby, I urge you to read these articles.

Bleached coral

Earlier I said that, to a certain extent, I concur with Bradbury’s piece. Let me explain.

Firstly, it is the reef environment that we have known for the past couple of centuries that we are going to lose, there will still be some form of ‘reef’ system in years to come and it will be home to many wonderful creatures but it will be different to the reef environment we known. This is change, not loss.

Central to this change will be the eventual loss of the Scleractinians, the reef building stony corals. This will then lead to the loss of certain reef fishes, the fishes that rely on the reef structure for shelter and for food. Some fishes will adapt to a changed environment (after all, many fish species readily adapt to the reef aquarium environment) others won’t. It might be a question of nutrition – think obligate corallivores such as Butterflyfishes without their food source of coral polyps. It might be the question of habitat degradation and how the loss of the habitat previously provided by absent stony corals makes juvenile fish vulnerable to predators (coincidental to the discussion at the New York Times, research has been published this week illustrating how habitat loss can affect juvenile fishes see, ‘Lethal effects of habitat degradation on fishes through changing competitive advantage’ by Mark I. McCormick of James Cook University.

In the short term responsible reefkeepers should consider themselves ambassadors for the reefs, showing off the wonderful animals resident in their reef aquariums to those outside the hobby, showing them the organisms that we are at risk of losing through climate change. By doing this we can create a greater awareness of what we risk losing and, perhaps, help slow or reduce the expected losses.

We cannot conserve the reefs as we know them without some fantastic technical fix that can prevent further deterioration almost instantly. We cannot maintain the diversity of species that we have known without this technical fix going further and reversing conditions on the reef back to those before mankind’s negative influence.

Long term, hobbyists in years to come should still have access to many wonderful fishes and invertebrates; it’s just that they will be representatives of an ecosystem different to the one with which we are familiar.

If you fancy joining this discussion from a reefkeepers point of view, please send your comments to me here at Reef Ramblings.

31 July 2012

Further to this subject, see ‘Are Coral Reefs really doomed? on the Independent website.

Photos courtesy ICRS 2012

Tim Hayes

Midland Reefs

©2012

Up until now I’ve pretty much ignored stories about sharks, not seeing their relevance to coral reefs and reefkeeping, the core subjects of Reef Ramblings; but research presented at ICRS 2012 demonstrating how sharks are an integral part of coral reef communities, has caused me to reassess this view.

Declining shark populations owing to over fishing are having an adverse affect on reefs; the removal of the apex predator is allowing an increase in the populations of medium size predators such as emperors and snappers resulting in a corresponding decrease in the populations of smaller herbivores such as parrotfish and damselfish that are vital to coral growth because of their role in keeping algae under control.

Research by Dr Mark Meekan, principal research scientist at the Australian Institute of Marine Science (AIMS) shows that the parrotfish that tend coral reefs are in decline in regions where sharks have disappeared, proving the apex predators are vital to reef health. His research looked at reefs northwest of Western Australia where shark stocks have been devastated to meet the Chinese demand for shark fin soup.

“We’ve really ignored sharks as a component of reef communities,” he said, “they’re a key component of the system and even in the best managed places, such as the Great Barrier Reef, we have situations where stocks are declining.”

Shark populations need to be preserved as part of coral reef management, grey reef and white-tipped sharks populations on the Great Barrier Reef are dropping at an alarming rate, Dr Meek said the finding was a call to action to preserve shark populations and “If we’re going to ensure our reefs are around for generations to come, we need to start at the top and with the apex predators”.

Additional research from James Cook University’s Prof Sean Connolly shows that there can be up to 90 per cent fewer reef sharks in fished zones compared with no entry zones.

What can you do as a hobbyist?

One reason that I’ve tended to steer clear of writing about sharks is that I don’t advocate keeping any species of shark in a home aquarium unless you have the resources to provide a system equal to that of a public aquarium.

As a hobbyist the best thing you can do to help conserve sharks is to sign up to a pro-shark campaigns, particularly an anti-finning campaign. There are many organisations out there but as a starting point I’d suggest the Shark Trust, a UK charity for Shark Conservation.

The Shark Trust describes shark finning for the shark fin soup market as: “… the wasteful practice of removing shark fins at sea and discarding the carcass, often still alive, overboard. Tens of millions of sharks are caught each year for their fins. An upper estimate proposes that the fins of as many as 73 million sharks are traded annually. Finning is illegal in many parts of the world including Europe. Despite this in most countries it is still legal to buy and sell shark fins. However, weak legislation and ineffective enforcement often undermines shark-finning regulations. The high value of fins further encourages the exploitation of regulatory loopholes.”

Tim Hayes

Midland Reefs

©2012

11/7/12

One of today’s sessions at ICRS 2012 was of particular interest to reefkeepers; entitled Reefonomics, this session looked at the trade in live fish covering both the growing demand for live reef fish for the restaurants of China and at the trade in fish and corals for the ornamental sector, the reef aquarium industry.

Dr Liz Wood of the UK’s Marine Conservation Society gave the presentation that concentrated on the aquarium industry, focusing on the issues of biological sustainability along with those of equity and fair trade.

Photo: E. Wood

Biological sustainability

The issues here include

• The importance of monitoring and managing aquarium fisheries to ensure sustainability.
• Although there is currently no evidence of any species collected for the marine ornamental trade being at risk of global extinction, there is evidence of local depletions. Intensity of collection, the population size and the biological characteristics of the species concerned.
• Over-harvesting of target species may have ‘trickle-down’ effects on reef ecology and needs monitoring
• The continuing use of cyanide in the capture of aquarium fish is still a significant problem. This is a toxic chemical that indiscriminately kills other reef organisms, including corals, and can cause long-term damage to target fish, causing later mortalities.
• Post-harvest mortalities i.e. significant losses occurring due to stress, poor handling, and disease, especially in areas where journey times are long.

Equity and fair trade issues

The aquarium market is considered to be low volume but high value, with the potential to support livelihoods and provide economic stability for low-income coastal communities, but in areas such as Indonesia and the Philippines where middlemen are involved the prices paid to fishers are very low. (For more on the subject of low prices paid to fishers, see: The Fisherman & his wife – a true story from Serangan, Bali)

Solutions.

The solutions suggested include:

• Limiting fishing effort by regulating and licensing the number of collectors.
• Ensuring that vulnerable species are not over-exploited by establishing quotas.
• Applying ‘zero catch quotas’ to protect rare or vulnerable species.

Photo: E. Wood

Conclusions.

The presentation concluded by suggesting a number of actions that could improve management and conservation of resources:

• Collaboration between management authorities, scientists, and aquarium fishers to investigate resources in collecting areas and produce mutually agreed quotas, especially for vulnerable species.
• Use of fishery logbooks to record species and numbers of individuals caught, collecting areas, and time spent collecting.
• Regulation of collecting effort by licensing and restricting the number of collectors.
• Designation of no-take areas to help conserve stocks and to act as control sites to compare with areas where collecting occurs.
• Cessation of trade in species that are known to have poor chances of survival until such time as husbandry problems have been solved.
• Concerted efforts to eradicate use of cyanide. There is a newly developed cyanide test that may prove to be a significant help.
• Introduction of mandatory minimum standards of handling and welfare and appropriate training and inspection schemes at all stages.
• Development of mariculture in countries of origin to relieve pressure on wild stocks.
• Certification to help promote sustainable fisheries and good practice.

Abridged and adapted from Fact Sheet for Marine Aquarium fisheries and trade by Elizabeth Wood. To see the full sheet click here.

Editorial comment.

There is nothing in this presentation that I take issue with, indeed I find myself in full agreement with the content and would perhaps go a little further in wanting to introduce mandatory minimum standards of handling and welfare along with appropriate training and inspection schemes for retailers in the importing countries.

A brief comment on the point about cessation of trade in species that are ‘known to have poor chances of survival, until such time as husbandry problems have been solved’. I would favour a restriction on export, not a ban, otherwise advanced aquarists will not have the opportunity to develop the husbandry protocols required for the successful maintenance of these species.

I welcome comments regarding the issues covered here.

Tim Hayes

Midland Reefs

©2012

9/7/12

Today marks the start of the 12th International Coral Reef Symposium (ICRS 2012) at the Cairns Convention Centre, Cairns, Australia. Held once every four years, the 5-day event brings together scientists from 80 countries, to present cutting-edge science and share the latest advances from international experts in coral reef conservation. The research and findings presented at the ICRS 2012 are fundamental to informing international and national policies and the sustainable use of coral reefs globally. Some 2,000 delegates, scientists, resource managers, conservationists, economists, educators and graduate students, from around the world are expected to attend the event

The event has been launched with a Consensus Statement on Climate Change and Coral Reefs with more than 2,400 signatures from the scientific community, worldwide, urging governments to take action for the preservation of coral reefs.

Topics and Issues

Coral reefs are declining rapidly almost everywhere. The symposium will cover the full spectrum of coral reef science, with the aim of sustaining reefs, and feature more than 1,500 talks and posters.

Topics include: coral reefs and climate change, ocean acidification, coral reef health and recovery, the role of Marine Protected Areas (MPAs), managing reefs sustainably, and the Coral Triangle Initiative.

Plenary speakers, 22 Symposia and 72 Mini-Symposia, daily media briefings and other special events will illustrate coral reef threats, conservation strategies and the future of reefs.

History

Every four years the International Society for Reef Studies (ISRS), the world’s largest society officially focused on coral reefs and reef issues, convenes this major international scientific conference, the ICRS, sharing the latest knowledge and leading edge technologies about coral reefs worldwide. ICRS gatherings are critically important opportunities for advancing coral reef science, management and conservation, particularly at a time when our need to improve our understanding and management of coral reefs grows ever urgent.

The ICRS is the world’s pre-eminent meeting dedicated to coral reef science. Since the first Symposium was held in 1969 at the Central Marine Fisheries Research Institute in Mandapam Camp, India, the conference has grown from participants representing 11 countries to a global scientific event with 2,000 attendees from more than 80 countries.

To learn more about ICRS 2012, please visit the event’s website: www.ICRS2012.com

Over the course of the conference I hope to be able to bring you news of any issues that are of importance to reefkeepers.

Tim Hayes

Midland Reefs