The global trade in marine ornamental species

Conservation issues
might be substantial for the time frame of such a study and
thus results need to be evaluated with care. The study also
showed that, although the three most heavily collected
species were herbivorous (Zebrasoma flavescens, spotted
surgeonfish (Ctenochaetus strigosus) and Acanthurus
achilles), and suffered significant reductions in abundance
at collection sites, no increases in algae abundance were
recorded when compared with control sites 120 .
Sea anemones
Life histories
While a huge diversity of species is demanded for the
aquarium trade, a large part of the trade tends to be
centred on individual species. These species’ vulnerability
to collection will depend on a number of life history
parameters, in particular growth, reproduction and
recruitment 54 .
Stony corals
Overall, there is very little information available on the life
history characteristics, growth rate or reproduction mode
of most coral genera in trade. Environmental conditions
influencing individual corals tend to be responsible for
great variations in life history characteristics. The same
species of coral sampled in two different locations may
display a different mode of reproduction and great
variation in growth rate. For example, coral specimens at
shallower depth tend to grow faster than specimens
found in deeper water 135 .
Corals show various sexual characteristics,
including two different types of sex, gonochoric (separate
male and female colonies) and hermaphroditic (single
individual is both male and female). In a hermaphroditic
coral (e.g. most corals in the genera Acropora and
Cynarina), a single individual is capable of producing both
eggs and sperm. Examples of gonochoric corals include
Catalaphyllia, Euphyllia, Goniopora and Heliofungia.
Corals also exhibit two distinct modes of reproduction:
brooding and spawning. In brooding corals, eggs are
fertilized inside the coral polyp and are released as fully
formed planula larvae that are ready to settle onto reef
substrate. Spawning corals, on the other hand, release
their gametes into the water column, where fertilization
and larval development takes place externally. Spawning
in hermaphroditic species is usually restricted to one
or a few nights each year, and occurs synchronously
throughout each population. Gonochoric spawners, on the
other hand, tend to have longer breeding periods and less
tightly synchronized spawning episodes 136 . Significant
reductions in population densities of corals due to
collection of colonies for the aquarium trade could have
implications on their reproductive success, and thus longterm
reef stability and health.
Of all 100 species of sea anemones occurring
throughout the world’s oceans, only ten are hosts to
anemonefish 132 . Anemonefish, on the other hand,
with the exception of Dascyllus trimaculatus, are
always associated with anemones and can only
be found in parts of the Indian Ocean, Red Sea
and Pacific Ocean (pictured are Barrier Reef
anenomefish, Amphiprion akindynos). Anemones and
their obligate symbionts xvi are very popular with
marine aquarists due to their colourful displays, ease
of care and longevity in captivity. In the Florida Keys,
collectors with the appropriate licence may harvest
400 giant sea anemones (Condylactis gigantean) per
vessel per day. Estimates show that an annual
average of approximately 11.8 million anemones
were landed between 1997 and 1999, with more than
90 per cent of these collected in the Florida Keys 133 .
Data from collectors’ logbooks in the Olango region,
Philippines, revealed that fishers in the region landed
510 sea anemones (equivalent to 1.7 per cent of all
collected organisms) and 17,160 anemonefish
between January and April 2002 134 .
In an analysis of the marine ornamental fish
trade undertaken in the Maldives in 1992, the authors
voiced concern over the potential local overexploitation
of sea anemones and the possible negative impacts a
lack of suitable habitat (i.e. anemones) may have on
local clownfish populations 90 . Indeed, anemonefish
strictly depend on anemones, recruiting to them as
larvae and utilizing them as adults. Results of the only
study to date addressing the population-level impacts
of collecting marine ornamentals (in this case sea
anemones) show that close to 60 per cent of the catch
of collectors in the Philippines consisted of anemonefish
and anemones, and that both these resources
exhibited significantly lower densities at exploited
sites 134 . Moreover, the low abundance of sea anemones
explained 80 per cent of the reduced density of
anemonefish recorded in collection areas 134 .
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