The understanding the state of conservation of marine ecosystems and the
distribution and recovery capacity of marine species continue to gain momentum
among marine scientists, marine resource users and other stakeholders. The main
concern is overfishing, which affects the supply of seafood, income generation
for large, medium and small-scale fisheries and the livelihoods of
resource-dependent coastal communities, especially those in the developing
world.
Of the approximately
250,000 catalogued marine species, about 16,000 species are exploited by
commercial fisheries. Projections made by marine scientists estimate between 2
to possibly 10 million fish species yet
to be discovered and probably exploited.
Predictive models
coupled with bibliometric analyses showed that in the first decade of 2000 the
number of authors describing new species each year increased to up to 4,900
authors. In Brazil, which covers almost half of South America and holds more
than 20% of the total number of species on Earth, the species richness and
range of known distribution grows each year. Surprisingly, in Brazil and
elsewhere, new species are still being discovered and described even among
large-bodied or economically important groups. Clearly, the rate of discovery
is greater for taxonomic groups poorly studied in the past.
The number of marine
species not described is partly due to the number of habitats and geographical
areas that remain unexplored. One side effect is the current knowledge gap on
the distribution of species along its expected range. This was the case of two
coastal species in Brazil, recently registered in the coastal fishing of Rio
Grande do Norte, on the northeastern coast of Brazil: the pacuma toadfish (Batrachoides surinamensis) and the spotted
ocean triggerfish (Canthidermis maculata).
Pacuma toadfish are
commonly found in shallow brackish waters of estuarine environments and were
recorded in the northern portion of the state, while spotted ocean triggerfish are an
offshore fish that have a tropical circumglobal distribution; its presence was
recorded in the central portion of the state. The state of Rio Grande do Norte
was, until then, the only gap in the expected distribution range for pacuma
fish. On the other hand, it was expected that the spotted ocean triggerfish
would occur along the entire Brazilian coast, although it was previously
recorded only in two places: one in the northeast (Bahia state) and one in the
south (Santa Catarina). Both species are listed as being of Least Concern by
the International Union for Conservation of Nature - IUCN (Collette, 2010,
Laws, 2015) and by the Brazilian Red List of Threatened Species (Decree 445,
Brazilian Red List, 2014), and there is no record of their exploration in Rio
Grande do Norte.
In general, most of
the research concerns commercially important fish, explaining why fish, such as
these two recently described, were not noticed. In addition to misreporting or
total absence of reporting, there is also the risk of wrong labeling, since
many species are often landed as fillets, making it difficult to identify and
protect them properly. Finally, there has been a growing global demand for triggerfish
for human consumption, for export and for aquarium purposes, making fishing
pressure even heavier on this species.
We confirmed this
trend, since after our first registration of the spotted ocean triggerfish, we
registered the total landing of 1.6 tons of the species in five months of
landing records in the main port of Natal (in the state of Rio Grande do
Norte). On average, it represents 230kg of species landed monthly and more than
1,500 individuals captured per month only in the main port of Rio Grande do
Norte. In terms of research, this is just the tip of the iceberg, , a lot more
ought to be done before we can truly understand these species and attribute a
precise conservation status to C.
maculata and B. surinamensis.
If, on the one hand, commercial
fishing can take these species out of the shadows, on the other hand, it can
also lead them to exhaustion, especially if fishing has only started focusing
on them because of a shortage of previously preferred targets. Therefore, while
such records may boost interest in the economic importance of spotted ocean
triggerfish in the Western Atlantic, as suggested by the recorded catch rate, we
may not have time or human and economic resources to assess the ecological
status of these resources before they are overexploited.
 |
Pacuma toadfish (Batrachoides surinamensis) was recorded in Porto do Mangue. Spotted
ocean triggerfish (Canthidermis maculata)
was recorded in Natal harbor.
|
Roughly 100 individuals of Canthidermis maculata landed on 2nd
March 2017 in the main port of Natal (Rio Grande do Norte state). Total
landings recorded on this date reached 600 kg of the species.
By Adriana R. Carvalho
Paper referred:
Garcia Jr, J.; Alves,G.A.; Oliveira J.E.L.; Carvalho A.R. 2017. First record of Batrachoides surinamensis (Bloch & Schneider 1801) and Canthidermis maculata (Bloch, 1786) (Pisces: Teleostei) from Rio Grande do Norte, northeastern coast of Brazil. Check List 13(3): 1-4. https://doi.org/10.15560/13.3.2119
References used:
Appeltans, W. 2012. The Magnitude of Global Marine Species Diversity. Current Biology 22: 2189–2202. doi: http://dx.doi.org/10.1016/j.cub.2012.09.036
MMA (2018) Biodiversidade. http://www.mma.gov.br/biodiversidade. Accessed 17 Jan 2018.
Sahayak, S., Joshi K.K. and Sriramachandramurty V. 2014. Taxonomy of the Ocean
triggerfish, Canthidermis maculata (Tetradontiformes, Balistidae) from the Indian coast. J. Mar. Biol. Ass. India, 56 (2):56-61. doi: http://dx.doi.org/10.6024/jmbai.2014.56.2.01770A-08
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