The global trade in marine ornamental species

From ocean to aquarium
species such as angelfishes and butterflyfishes are
known as broadcast spawners, i.e. they spread their eggs
freely in the water column, and are therefore more
difficult to culture in captivity; they also usually require
hormone treatment to induce spawning. To date, the
greatest obstacle to successful tank breeding of ornamental
reef fish is rearing larvae beyond the sixth to
eighth day of development, a time typically associated
with failure to initiate larval feeding 47 . This is often due to
larval feeds being too large or not meeting the nutritional
requirements of fish larvae. Once the larvae transform
into small juveniles, they are weaned onto semi-natural
diets and various prepared rations and can be transported
and sold 201 . Beside technical challenges, the high price
commanded by some cultured aquarium fishes compared
to those wild caught often undermines their economic
viability 37 .
The increasing use of mariculture to supply coral,
other invertebrates and fish to the marine ornamental
trade raises its own suite of issues. Firstly, should rearing
facilities be established mainly in developed countries, as
the trend so far seems to indicate xxi . Relations between
the different players involved in the marine ornamental
trade may be altered, possibly depriving local fishers of
employment and losing the community- and nationallevel
benefits the trade provided 203, 204 . This would be
contrary to the first article of the Convention on Biological
Diversity ratified by 170 countries 205 (but not the United
States), the objectives of which are: ‘the conservation
of biological diversity, the sustainable use of its components
and the fair and equitable sharing of the benefits
arising out of the utilization of genetic resources,
including by appropriate access to genetic resources and
by appropriate transfer of relevant technologies, taking
into account all rights over these resources and to
technologies, by appropriate funding.’ Development of
facilities in source countries has the potential to raise the
standards among rural communities and provide income
opportunities for a great number of households due to its
ability to generate considerable income per unit area,
with high export earnings 5 . Furthermore, setting up
hatcheries in source countries would also reduce the risk
associated with escapes and, by extension, the risk of
introducing exotic species.
A relatively recent type of mariculture whereby
fish larvae are captured via means of light traps 206, 207 or
crest nets (shaped like funnels and placed on the reef
edges) has been raising much interest. Not only would
it provide local communities with the benefit of such
activities and/or provide them with an alternative
Captive breeding of seahorses
In light of expressed concerns of overexploitation of
seahorse populations, the possibilities for captive breeding
are of great interest and a number of captive breeding
projects have been set up around the world. The Seahorse
Trust 202 reports that it has bred 18 species of seahorse
with varying levels of success; for example, it has bred six
generations of Hippocampus capensis with a 90 per cent
success rate, compared to only two H. comes (pictured)
out of many broods. In addition, the Tropical Marine Centre
in the United Kingdom has captive breeding facilities and
breeds seahorses, e.g. H. barbouri. However, it is only if
aquaculture is developed as an alternative livelihood for
fishers in source countries that it can be highlighted as
having great potential for integrating conservation and
sustainable development objectives 167 . Results of a recent
protocol developed for culturing H. kuda, one of the most
heavily exploited species for the aquarium trade, in the
source countries are encouraging. They indicate that H.
kuda grows rapidly from birth to 14 weeks and showed
highest survival rates when fed Artemia (brine shrimp, a
commonly available feed for aquarium fish) enriched with
a locally available crustacean, Acetes spp. 167 .
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