Special Issue "Endangered Fish, Rivers at Risk: Spatial Aspects of Freshwater Biodiversity Conservation"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Biodiversity and Functionality of Aquatic Ecosystems".

Deadline for manuscript submissions: 31 October 2022 | Viewed by 2596

Special Issue Editors

Dr. Aaron Koning
E-Mail Website
Guest Editor
Department of Biology and Global Water Center, University of Nevada, Reno, NV, USA
Interests: conservation biology; ecosystem ecology; rivers; aquatic ecology; fish ecology; freshwater ecology; aquatic ecosystems; community structure; field sampling; freshwater biology; stream ecology; freshwater fish ecology; limnoecology; electrofishing; experimental biology; freshwater fisheries
Dr. Zeb Hogan
E-Mail Website
Guest Editor
Department of Biology, University of Nevada, Reno, NV 89557, USA
Interests: conservation biology; aquatic ecology; fisheries; environmental education; science communication
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Special Issue Information

Dear Colleagues,

Freshwater ecosystems support over 18,000 fish species, a quarter of all known vertebrates, as well as thousands of other animal and plant species. These critical ecosystems, and the diversity of life they support, are highly imperiled by numerous, interacting threats. Habitat degradation, flow modification and fragmentation, non-native species introductions, pollution, overexploitation, and climate change have resulted in IUCN threatened status for nearly one-third of all listed freshwater fish species. While the threats facing freshwaters and freshwater fishes are well documented, their continued decline suggests current conservation strategies provide insufficient protection for many threatened fish populations. In recent years, there has been a growing recognition of the benefits of protecting riverine habitats and conserving connectivity for aquatic biodiversity. The aim of this Special Issue is to both highlight spatial approaches for the protection of threatened freshwater fishes and to identify the challenges to wider implementation of these strategies. Successful protection for threatened freshwater fishes, and other species, will require continued development of diverse conservation strategies, including spatial protections. By identifying cases where durable river/habitat protection has effectively protected at-risk fish populations, and conversely, where spatial protection (or better understanding of spatial factors) is needed or could be applied, this Special Issue will add to the portfolio of tools available for effective global freshwater conservation. 

Contributions are welcome on topics such as the past, present, and future status of endangered freshwater fishes and their habitats, spatial aspects of fish natural history and population genetics, migration and ecological connectivity, explorations of the importance of scale and ecosystem process when considering conservation approaches and outcomes, scale and spatial components of threats and human impacts, single species vs. ecosystem-based approaches, and obstacles and approaches to transboundary management, policy, and conservation. Commentaries, short communications, literature reviews, field-based research, and case studies are all welcome.

Dr. Aaron Koning
Dr. Zeb Hogan
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • conservation
  • biodiversity
  • conservation biology
  • fish biology
  • fisheries science
  • fisheries management
  • fish ecology
  • ecosystem ecology
  • aquatic ecology
  • freshwater-protected areas
  • fish reserves

Published Papers (2 papers)

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Research

Article
Dispersal and Survival of Captive-Reared Threatened Fishes in a Tonle Sap Lake Reserve
Water 2022, 14(19), 2995; https://doi.org/10.3390/w14192995 - 23 Sep 2022
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Abstract
The Tonle Sap Lake in Cambodia supports several species of threatened megafish and contains one of the largest networks of freshwater fish reserves in the world. Despite these traits, this system remains understudied in terms of its utility for endangered fish conservation and [...] Read more.
The Tonle Sap Lake in Cambodia supports several species of threatened megafish and contains one of the largest networks of freshwater fish reserves in the world. Despite these traits, this system remains understudied in terms of its utility for endangered fish conservation and restoration. This study was the first of a series of planned fish releases designed to test the effectiveness of conservation supplementation programs in the Tonle Sap Lake. In March 2022 (during the dry season), 1582 captive-reared fishes, including 1538 striped catfish Pangasianodon hypopthalmus, 42 giant barb Catlocarpio siamensis, and two Mekong giant catfish Pangasianodon gigas, were tagged and released into a 986-hectare fish reserve to assess post-release dispersal and survival. Brightly colored external tags with unique identification numbers were used to facilitate tag returns. A high-profile release event was held to raise awareness about the activity, bringing attention to the importance of fish reserves and endangered species conservation, and disseminating information about the research and tag return and reward program. This, in concert with other efforts, served to be an important education and outreach tool and increased tag return rates. We found that mortality from fishing was rapid and very high. Nineteen percent of released fishes were recaptured in the first 2 days after the fish release, and 46% were recaptured by day 83 after the release, indicating intense fishing pressure on the Tonle Sap Lake fisheries. Eighty percent of recaptured fishes were caught in stationary gill nets, most within 10 km of the release site. Fishing mortality rates were independent of fish size or source (pond-reared or cage-reared). Environmental DNA (eDNA) was found to be capable of detecting each of these species’ presence in the water at the release site and could prove to be a useful tool for endangered species monitoring and restoration. Future research should explore alternative release timing, release location, and other methods of increasing post-release survival. Ultimately, underlying sources of mortality, especially fishing, will need to be addressed for conservation supplementation programs to succeed in the Tonle Sap Lake. Conservation supplementation should not be viewed as a substitute for more fundamental conservation measures, such as maintenance of environmental flows, preservation of ecological connectivity, and science-based fisheries management. Full article
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Article
Deep Pools: Ecological Sanctuaries for Steindachneridion melanodermatum, a Large Endemic and Endangered Pimelodid of the Iguaçu River
Water 2021, 13(12), 1700; https://doi.org/10.3390/w13121700 - 19 Jun 2021
Cited by 1 | Viewed by 1646
Abstract
Steindachneridion melanodermatum, an endemic and endangered species, is the largest catfish in the Lower Iguaçu River basin. Currently, the wild population of this species no longer exists in most of this basin, probably due to the loss of habitat by successive hydroelectric [...] Read more.
Steindachneridion melanodermatum, an endemic and endangered species, is the largest catfish in the Lower Iguaçu River basin. Currently, the wild population of this species no longer exists in most of this basin, probably due to the loss of habitat by successive hydroelectric dams. This study evaluated the spatial distribution and abundance of S. melanodermatum in the last free-flowing river stretch of approximately 190 km downstream from the Salto Caxias Dam, upstream of the Iguaçu Falls, as well as some tributaries. Hydroacoustic and fishing campaigns were performed between September 2010 to December 2016 to characterize the preferred habitat. A total of 180 specimens was sampled with higher abundances in a protected area near Iguaçu Falls in the Iguaçu National Park. Twenty-four deep pools were identified with maximum depths ranging from 5 to 25 m: 21 pools were along the main channel of the Iguaçu River, and three pools were in tributaries. Deep pools are preferential habitats for this species, especially the deep pool called Poço Preto (P23) and its surroundings. Conservation strategies are required to protect these habitats and prevent S. melanodermatum from becoming extinct, such as establishing deep pools as ecological sanctuaries, intensifying the inspection of illegal fishing, and maintaining dam-free tributaries. Full article
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