14 research outputs found
Sturgeons in large rivers: detecting the nearāextinct needles in a haystack via eDNA metabarcoding from water samples
Sturgeon populations are declining worldwide and are the target of extensive conservation
efforts. Addressed in several pieces of legislation, sturgeons have received considerable
attention as flagship or umbrella species. Despite the need for a better understanding
of the distribution and population status, the use of traditional sampling methods failed
in the past, thereby hampering reliable assessments, a prerequisite for conservation. Here,
we describe the development and application of an environmental DNA (eDNA) metabarcoding
approach for detecting rare sturgeons in large rivers. Exemplarily, we developed
a reference database for five native Danube sturgeons (Acipenser stellatus, Acipenser
gueldenstaedtii, Acipenser ruthenus, Acipenser nudiventris, and Huso huso) and two nonnative
species (Acipenser baerii and Acipenser transmontanus), assessed these ex situ, and
used eDNA as a detection tool along the entire length of the Danube (Europe, ~ 2850 km)
and major tributaries. In ex situ analyses, all assays yielded positive amplifications for the
assessed sturgeon species. In the Danube, the presence of A. ruthenus was confirmed at 14
of 29 sites (48.3%), and in 2 of 18 tributary sites (11.1%), providing the first comprehensive
large-scale biogeographical snapshot of this species. Relative number of reads assigned to
A. ruthenus varied between 0 and 2.5%, with sites registering positive detections being
clustered in 3 sections of the Danube. Our findings enabled us to confirm the advantages of
eDNA monitoring over traditional sampling methods for comprehensive whole-river snapshot
studies of sturgeons conducted on a large geographical scale, and therefore we consider
it to be a promising approach for application in conservation measures, fisheries management,
scientific studies, and adaptive management plans for sturgeons on a global scale
Fish Biozonation in the Balkan Peninsula, Especially in Bulgaria: A Challenge
Fish are important elements of aquatic ecosystems. Their communities naturally follow the river continuum and have been well described in the western European freshwater watersheds. In regions of higher endemism, such as the Balkan Peninsula, the widely accepted fish zonation of Illies is doubtfully relevant. In this study, a more suitable categorization of lotic and lentic freshwater ecosystems in Bulgaria is proposed, based on 389 multimethodological and multihabitat fish sampling occasions. Referent-type communities have been determined for 33 types of recognized water bodies. Adapted zonation of Illies is a rough estimation of the real distribution of fish assemblances in the country; moreover, sensitive and/or endemic species are generally of restricted distribution and abundance. In view of the lentic ecosystems, they can be divided into salmonid and cyprinid, at approximately 1500 m above sea level
Run7_tag
File containing experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated
Run3
Compressed file containing:
1) Forward sequence file
2) Reverse sequence file
3) File with experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated
Run6
Compressed file containing:
1) Forward sequence file
2) Reverse sequence file
3) File with experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated
Run9_tag
File containing experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated
Run5_R1.fastq
Compressed file containing forward sequence fil
Run5_R2.fastq
Compressed file containing reverse sequence fil
Run10
Compressed file containing:
1) Forward sequence file
2) Reverse sequence file
3) File with experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated
Run8
Compressed file containing:
1) Forward sequence file
2) Reverse sequence file
3) File with experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated