Sustainable Harvest
Marine Aquarium Trade
Many marine fish keepers these days are attracted to the hobby because they have developed a fascination after visiting or viewing natural coral reefs. In the past it tended to be the result of a progression from goldfish in a bowl to freshwater tropicals, and finally, the ultimate challenge of marine aquaria keeping. You may feel an apprenticeship in simpler forms of aquaria is necessary and logical to prepare a hobbyist for keeping marines. On the other hand, the new breed of marine fish keepers come with a high regard for nature and natural reef habitats from which tropical marines are derived. They are prepared to accept the large commitment in time and cash outlay to avoid losses and minimise their demands on natural living reef resources. In the UK we do not necessarily believe we are at the cutting edge of the marine hobby - but most of us feel we do a pretty decent job of keeping marines. There are hobbyists reef systems around the country to rival the best found anywhere in the world. So it may come as a surprise to learn that researchers into the trade in hard corals at the World Conservation Monitoring Center in Cambridge found that eminent US and European experts in the hobby regard UK reef keepers as years behind those in North America and Europe. This despite the rather damning evidence in the report that an estimated 1200 tons of live coral is presently maintained in US aquarium despite something like twice this amount (2427 tons) being imported into the US in the 1990s, mostly in recent times. Not a very good record of survival for self declared experts in the field.
Survey
A survey of UK fish keepers conducted by one expert revealed that hard corals do not survive much longer that two years in UK hobbyists aquariums. The report also quotes a researcher who assessed that the average age of coral traded live is about 3 years. Simple arithmetic seems to indicate that if UK fish keepers need to replace live hard coral colonies every two years, collection of corals from the wild for the UK cannot be sustainable. New colonies which would have to grow to replace those previously collected would not have sufficient time to reach marketable size before replacement. But this is an over-simplification, even if it does serve to indicate what sustainable extraction of corals from reefs might entail. Let me reassure you that "The Global Trade in Corals" by Dr Edmund Green and colleague Francis Shirley is not an exercise knocking the hobby but an authoritative work much better researched from the hobbyists point of view than earlier works using dated, inaccurate information.
The Report also reveals that there has been a dramatic increase in live coral trade due to the increasing popularity of reef aquaria across North America and Europe. The report also quotes industry figures produced by the Pet Industry Joint Advisory Council which assesses that in 1999 some 622,000 American households alone will be maintaining marine aquaria - the vast majority tropical systems. Using data sourced from a survey of 683 marine fish keepers it is also estimated that something like 6 m. pieces (average 200g per piece) of live hard corals and also some 18 million colonies of soft corals are currently kept in tanks in the US. According to this survey the average size of marine aquariums in the US is around 200 to 500 l. while in Germany it is nearer 500 l. No data is available for the UK specifically, as our statistics are included in a "rest of the world" category. It would appear though that we follow the pattern of the US regarding tank size. The average aquarium is a mixed show tank with a variety of inverts and fishes. Tanks where fish dominate are in the minority, unlike, say 10 years ago. There is also a sizable number of marine hobbyists with specialist systems holding hard or soft corals. Live rock is used in many hobbyists systems with amounts as high as 0.5kg/l. of tank capacity, equating to over 100 kg live rock for a 50 gal. (225 l.) tank. Most hobbyists used between 0.1-0.2 kg/l. The numbers of live coral colonies per liter were around the 0.05 to 0.10 range. The average 50 gal. system holds a dozen to two dozen colonies. The proportion of hard to soft corals has also appeared to increase. Soft corals, until recently, dominated most reef aquariums but the survey found that, on average, reef aquariums now display a 50-50 split of hard and soft corals.
Coral Farming And Propagation
A very interesting development was the increasing use of propagated hard coral fragments. A significant number of hobbyists worldwide are now using cultured coral fragments, some tanks furnished with up to 50 percent from this source. Because of the increasing demand for live hard corals, coral farming and cultured corals would seem to be the way forward reducing the need to collect from the wild. Reef keepers attitudes towards this were sought during the survey. In answer to the question "Do you have regular access to cultured corals?" a third of the hobbyists in the US answered "Yes" while in Germany only 1 in 10 replied positively. The proportion appeared to be similarly low for those surveyed in the rest of the world class. This is not too surprising as the Solomon Islands are the main source of farmed corals, and trade almost exclusively with the US. Hobbyists asked whether "If available would you prefer cultured corals to wild?" mainly answered "Yes" but when asked "If available would you prefer cultured corals to wild only if they were cheaper?" national traits began to emerge with US hobbyists answering "No" in the majority while 60% of the German hobbyists replied that they were only interested if they were cheaper. Looking at the trade in live hard corals it is estimated the global trade worth around 5 million US dollars. in 1997 has increased in subsequent years. This converts to around 50 million US dollars of sales primarily in the markets of North America and Europe. Using data produced by CITES who have monitored the legal trade in hard corals over the period 1985-1997, 70 nations imported a total of 19,262 tonnes (34,6000,000 pieces) from 120 exporting nations over this period with the US accounting for more than 56% weight of the global trade compared with 15% for the EU. These last statistics are for live and dead corals imported for the curio trade.
Live corals were a small proportion of the whole trade (approx 100 tonnes per annum) but this has increased to constitute more than half by 1997 at around 600-700 tonnes. This large increase must be treated with some caution. The figures are based upon CITES statistics and permits for export and import of corals listed under Appendix II of the CITES list of endangered species. In 1955 there were only 17 genera of hard coral included in this appendix and it was no until 1990 this was increased to include more than 2000 general. In those earlier years all of the species being traded were not regulated or monitored as listed species. Similarly the number of signatories to CITES increased dramatically over the same period. It is the current situation that really matters; " The effects on coral populations of harvesting specimens for the aquarium trade can be profound but are likely to be localised and, on a global scale minimal because the amount of harvested is small" In answer to the question: "Although small is the global harvest in live corals for the aquarium trade sustainable through natural rates of reproduction and regeneration?" the report states that "an answer to this question is not readily available because of the difficulty of (i) assessing the age of corals in the trade, and (ii) the viability of rates of mortality in aquaria... trade in those species known to flourish in aquaria maybe sustainable and that trade in other species are probably not."
On the last point elsewhere in the report it is further concluded that live coral pieces in the trade "when assessed against published data on growth rates of difficult corals of these dimensions suggest that a typical live coral in the aquarium trade is at least 3 years old. Some species of coral can be expected to survive in home aquaria for many years , certainly more than 3, but the husbandry of other species is more difficult and mortality occurs in less. In the later case the amount of coral collected can not be sustained by reproduction and growth. However, in comparison to other extracted and destructive impacts on coral reefs such as mining and dynamite fishing, the effects of collection live coral for the aquarium trade are very small". Careful selection of hard corals is necessary. Species with a known mortality rate that will survive over three years and flourish in the aquarium increasing easily from fragments are what to aim for. Chatting to the reports main author, Edmund Green convinced me he put a lot of work into verifying the facts to provide the reports balanced picture. His reports has received the support of members of the trade such as TMC in the UK and by experts in public aquaria and the hobby.
Edmunds comments that the trade in live corals throughout the world is so tiny it is not worth considering in reef resource management terms BUT hobbyists should not be complacent. The trade is very visible and could easily be regulated. Reef keepers should promote the hobby by following the guideline in the report and support initiatives like the marine aquarium councils eco-labelling system. This allows hobbyists to choose live corals from members of the trade certified to comply with standards for quality product and practices.