Medidas de Gestao das Pescarias Marinhas e Aquicultura 2019 The State of World Fisheries and Aquaculture 2018 | Page 37

THE STATE OF WORLD FISHERIES AND AQUACULTURE 2018
Marine bivalves, which extract organic matter for
growth, and seaweeds, which grow by
photosynthesis by absorbing dissolved nutrients,
are sometimes described as extractive species.
When farmed in the same area with fed species,
they benefit the environment by removing waste
materials, including waste from fed species, and
lowering the nutrient load. Culture of extractive
species with fed species in the same mariculture
sites is encouraged in aquaculture development
planning and zoning exercises. Extractive species
production accounted for 49.5 percent of total
world aquaculture production in 2016.
aquaculture production, mainly because of the
aggregation of production data from several
major producing countries in East and Southeast
Asia, especially for finfish species that are
farmed in marine cages as well as in coastal
ponds. Most of the finfish production reported
under marine and coastal aquaculture in Africa,
the Americas, Europe and Oceania (Table 6) is
produced through mariculture.
FAO recorded 28.7 million tonnes (USD 67.4 billion)
of food fish production from mariculture and
coastal aquaculture combined in 2016. In sharp
contrast to the dominance of finfish in inland
aquaculture, shelled molluscs (16.9 million tonnes)
constitute 58.8 percent of the combined production
of marine and coastal aquaculture. Finfish (6.6
million tonnes) and crustaceans (4.8 million
tonnes) together were responsible for 39.9 percent.
Species produced
As of 2016, global production has been recorded
for a total of 598 “species items” ever farmed in
the world. A species item refers to a single
species, a group of species (where identification
to the species level is not possible) or an
interspecific hybrid. Species items recorded so far
include 369 finfishes (including 5 hybrids), 109
molluscs, 64 crustaceans, 7 amphibians and
reptiles (excluding alligators, caimans or
crocodiles), 9 aquatic invertebrates and 40 aquatic
algae. These numbers do not include those
species, known or unknown to FAO, produced
from aquaculture research experiments,
cultivated as live feed in aquaculture hatcher y
operation, or ornamental aquatics produced in
captivit y. In the past ten years, the total number
of commercially farmed species items recorded by
FAO increased by 26.7 percent, from 472 in 2006
to 598 in 2016, a combined result of FAO’s
investigative efforts and improvement in data
reporting by producing countries. However, the
diversification of the FAO data does not keep
pace with the actual speed of species
diversification in aquaculture. Numerous single
species registered in the official statistics of many
countries consist in realit y of multiple species
and sometimes hybrids. While FAO has recorded
only five finfish hybrids in commercial
production, the number of hybrids farmed is
much greater.
Aquaculture production with and without feeding
The growth of farming of fed aquatic animal
species has outpaced the farming of unfed
species in world aquaculture. The share of unfed
species in total aquatic animal production
decreased gradually from 2000 to 2016, shrinking
by 10 percentage points to 30.5 percent (Figure 8).
In absolute terms, the volume of unfed species
farming output still continues to expand, but the
expansion is slower than for fed species. In 2016,
the total unfed species production climbed to
24.4 million tonnes, consisting of 8.8 million
tonnes of filter-feeding finfish raised in inland
aquaculture (mostly silver carp
[Hypophthalmichthys molitrix] and bighead carp
[Hypophthalmichthys nobilis]) and 15.6 million
tonnes of aquatic invertebrates, mostly marine
bivalve molluscs raised in seas, lagoons and
coastal ponds.
In Asia, Central and Eastern Europe and Latin
America, filter-feeding carps are t ypically raised
in multispecies polyculture farming systems,
which enhance fish production by using natural
food and improving the water qualit y in the
production system. In recent years another filter-
feeding finfish species, Mississippi paddlefish
(Polyodon spathula), has emerged in polyculture in
a few countries, particularly in China, where the
production volume is estimated to be several
thousand tonnes.
Despite the great diversit y in the species
raised, aquaculture production by volume
is dominated by a small number of “staple”
species or species groups at national,
regional and global levels. Finfish farming, »
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