Name: Juliana Paulo da Silva
Type: MSc dissertation
Publication date: 27/09/2023
Advisor:
Name |
Role |
|---|---|
| Luisa Maria Sarmento Soares Filho | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Ana Carolina Loss Rodrigues | Internal Examiner * |
| ANDRÉ TEIXEIRA DA SILVA | External Alternate * |
| Heron Oliveira hilário | External Examiner * |
| Luisa Maria Sarmento Soares Filho | Advisor * |
| Roberta Paresque | Internal Alternate * |
Summary: This study presents for the first time the use of environmental DNA (eDNA) for detection
of an endangered fish species in Brazil. Trichogenes claviger occurs in first and second
order forested streams only in the headwaters of the Itapemirim basin. Until then, the
species was known only from two locations mountain regions, in the sub-basin of the
Picada Comprida stream, a source of the Caxixe river. The study aimed to determine
whether the eDNA metabarcoding approach works as an adequate tool to assess the
presence of the species. Though, a 12S marker was created, specific for the T. claviger
species. We found evidence of the catfish presence through eDNA samples in three of the
ten sites sampled. In addition to the target species of this study, it was possible to collect
traces of non-target species detected in the water samples. 25 species of vertebrates were
identified, of which 15 were fish, 5 mammals and 5 birds. Among these records, we
highlight the presence of exotic fish species, such as the tilapia Coptodon rendalli and
Oreochromis niloticus, and the species of bird, Scytalopus speluncae, which is in Danger
(EN) on the state list of Espírito Santo. Comparison between the methods for estimating
species composition per sampled stream demonstrates that the eDNA metabarcoding
approach identified more than twice as many stream species previously detected by
traditional collection methods, which used fishing gear such as nets and sieves. The
results achieved ensure a better understanding of the spatial distribution dynamics of T.
claviger, its conservation status, as well as insights into the vertebrate community
associated with catfish environments.
