scholarly journals The fisheries resources at sub-zones irrigation works of Omon - Xano and Quan Lo - Phung Hiep in the Ca Mau peninsula

2019 ◽  
Vol 18 (01) ◽  
pp. 98-108
Author(s):  
Van V. Mai
Keyword(s):  
Fish Species ◽  
Brackish Water ◽  
Irrigation System ◽  
Freshwater Ecosystems ◽  
Community Based ◽  
Fisheries Resources ◽  
Water Ecosystems ◽  
Notopterus Notopterus ◽  
Natural Water Bodies ◽  
Indigenous Fish Species

A study on the fisheries resources at sub-zones irrigation works of O Mon - Xa No and Quan Lo - Phung Hiep in the Ca Mau Peninsula was conducted from January to December 2016. The data on fish species compositions were collected from the field in six times a year in combination with using the prepared questionnaire for interviews of 240 fishing households inside and outside the irrigation system (IS) area in two freshwater and brackish water ecosystems. The results showed that the composition of fish species in the study area was diverse. The size of major fish species recorded in the study area was relatively small. The production of fish and shrimp in 2016 decreased by 50 - 60% as compared to 2012 and the production inside the IS area was lower than that outside the IS area in both ecosystems. Some indigenous fish species, such as Channalucius, Notopterus notopterus, Clarias macrocephalus, Clarias batrachus, Morulius chrysophekadion and Toxotes chatareus were rarely found in freshwater ecosystems. Similarly, the indigenous fish species of Arius maculatus and Otolithoides biauritus were rarely found in brackish water. Pterygoplichthys disjunctivus has established populations in many natural water bodies in this study area resulting in a threat to competition, diversity and abundance of indigenous fish species. There were many reasons for the significant decline of fisheries resources; for example, the IS has blocked the migration of aquatic species. Many fishermen used electricity, poisoning, catching broodfish and fry during breeding season and water pollution by waste from aquaculture pond rehabilitation in the study area. Thus, it is necessary to deploy a community-based model of fishery resources management and preservation in the Ca Mau Peninsula.

scholarly journals Abundance and biomass of assorted small indigenous fish species: Observations from rural fish markets of West Bengal, India

2018 ◽  
Vol 3 (3) ◽  
pp. 129-134 ◽  
Author(s):  
Dibyendu Saha ◽  
Santanu Pal ◽  
Supratim Mukherjee ◽  
Gargi Nandy ◽  
Anupam Chakraborty ◽  
...  
Keyword(s):  
Fish Species ◽  
West Bengal ◽  
Indigenous Fish Species

Sustained Impact of a Glacial Lake Outburst Flood on Winter Turbidity Regimes across the Land-Ocean Aquatic Continuum

2021 ◽  
Author(s):  
Ian Giesbrecht ◽  
Suzanne Tank ◽  
Justin Del Bel Belluz ◽  
Jennifer Jackson
Keyword(s):  
Freshwater Ecosystems ◽  
Glacial Lake ◽  
Mass Wasting ◽  
Outburst Flood ◽  
Fisheries Resources ◽  
Carbon Burial ◽  
Source To Sink ◽  
Creek Watershed ◽  
Glacial Lake Outburst Flood ◽  
The Impact

<p>Rainforest rivers export large quantities of terrestrial materials from watersheds to the coastal ocean, with important implications for local ecosystems and global biogeochemical cycles. However, the impact of episodic disturbance on this process is a critical knowledge gap in our understanding of land-sea connections. Fjords represent a global hotspot for terrestrial carbon burial in marine sediments, yet the relative importance of typical riverine fluxes vs. mass wasting fluxes is uncertain and dynamic. Similarly, mass wasting events can generate both an instantaneous pulse and a sustained shift in the material export regime. Riverine sediment regimes also have important implications for freshwater ecosystems and fisheries resources. A recent mass wasting event in Bute Inlet – Homalco First Nation traditional territory and British Columbia, Canada – presents an important opportunity to quantify the sustained impact of such an infrequent large disturbance on the source-to-sink linkages between glacierized mountains, rivers, and fjords.</p><p>On November 28, 2020, a landslide in the headwaters of the Elliot Creek watershed (118 km<sup>2</sup>) triggered a glacial lake outburst flood (GLOF) that eroded 3 km<sup>2</sup> of forested land and exported large volumes of water and terrestrial materials to the lower reaches of the Southgate River watershed (1986 km<sup>2</sup>) and ultimately to the head of Bute Inlet. Here we assess river and ocean surface turbidity over four winter months following the event, in comparison to pre-event measurements taken across all seasons in recent years. River turbidity was measured on the Southgate River above and below the confluence of Elliot Creek, beginning in December 2020, and at the mouth of the Southgate and nearby Homathko Rivers prior to November 2020. Bute Inlet turbidity was measured (every month to two months) starting in May 2017.</p><p>Prior to the GLOF event, Southgate River turbidity ranged from a low of 3.3 ± 0.4 FNU in the winter to a high of 71.4 FNU in the summer meltwater period. Since the event, Southgate River turbidity has been consistently elevated ≥6 times background levels recorded above Elliot Creek. At the extreme, on January 13, 2021, seven weeks after the GLOF, Southgate River mean turbidity (105.2 ± 3.3 FNU) was 32 times the background (3.3 ± 0.4 FNU), equating to a sustained increase in wintertime turbidity that sometimes exceeds the historical summertime peak. Given the typical coupling of turbidity with discharge, we expect further increases in turbidity with the coming freshet of 2021; the first meltwater season following the GLOF. These results suggest the potential for a sustained shift in the seasonal turbidity regime of the Southgate River and the estuarine waters of Bute Inlet. The elevated turbidity signals broader changes to: sediment export and carbon burial, the depth and seasonality of light penetration, river water quality, and spawning habitat quality for anadromous fish. Ongoing monitoring will be used to characterize the duration, dynamics, and potential recovery of elevated turbidity regimes across the land-to-ocean aquatic continuum in Bute Inlet.</p>

Diversity and abundance of cichlids in Ikere Gorge Reservoir, Iseyin, Oyo State, Nigeria

2021 ◽  
Vol 18 (1) ◽  
pp. 52-56
Author(s):  
S.O. Ajagbe ◽  
R.O. Ajagbe ◽  
O.S. Ariwoola ◽  
F.I. Abdulazeez ◽  
O.O. Oyewole ◽  
...  
Keyword(s):  
Fish Species ◽  
Riparian Forest ◽  
Abundant Species ◽  
Freshwater Ecosystems ◽  
Freshwater Species ◽  
Fishing Villages ◽  
Gorge Reservoir ◽  
Commercially Important ◽  
Sarotherodon Galilaeus ◽  
Fish Species Diversity

Cichlids are highly abundant and commercially important fish in freshwater ecosystems in Nigeria. This study examined the diversity and abundance of cichlids in Ikere Gorge Reservoir. Four fishing villages were randomly selected from 12 fishing villages in Ikere Gorge Reservoir as sampling sites. Cichlids were sampled randomly and examined from fishermen catch in each selected fishing village; were identified with appropriate keys; the weight and abundance of the catches were recorded. The data obtained was subjected to descriptive statistical analysis using SPSS (Version 20.0) software to determine the abundance of fish species. Fish species diversity was carried out by using Palaeontological Statistics (PAST). Eight species of cichlids were sampled in Ikere Gorge but Sarotherodon galilaeus was the most abundant species while the least abundant species was Pelmatolapia mariae. It was observed that, cichlids were  abundant in rainy season than in the dry season. Likewise, cichlids were abundant in Ikere-gorge reservoir but they have low diversity. This may be as a result of unsustainable fishing pressure and deforestation of riparian forest and sedimentation in Ikere-gorge reservoir. Therefore, to maintain sustainable fishing activities and improve cichlids population in Ikeregorge reservoir, unsustainable activities in and around Ikere Gorge reservoir should be put under control. Keywords: Cichlidae; freshwater species; dominant; Sarotherodon galilaeus; Pelmatolapia mariae.

Molecular characterization of small indigenous fish species (SIS) of Bangladesh through DNA barcodes

Gene ◽  
2019 ◽  
Vol 684 ◽  
pp. 53-57 ◽  
Author(s):  
Md. Sagir Ahmed ◽  
Md. Miraj Kobad Chowdhury ◽  
Luthfun Nahar
Keyword(s):  
Molecular Characterization ◽  
Fish Species ◽  
Dna Barcodes ◽  
Indigenous Fish Species

scholarly journals The Trend in Fish Species Diversity and abundance at Asejire Reservoir South Western Nigeria

2021 ◽  
Vol 5 (1) ◽  
pp. 1-9
Author(s):  
Augustine Omoike ◽  
Keyword(s):  
Species Diversity ◽  
Fresh Water ◽  
Fish Species ◽  
Fisheries Resources ◽  
Fish Species Diversity

The upsurge of population and industries around Asejire area necessitated a study into the fish species diversity and abundance for managerial purposes to determine the trend in the availability of fresh water fisheries resources in Asejire Reservoir within boundary of Oyo and Osun States in Nigerian

scholarly journals Monitoring spawning migrations of potamodromous fish species via eDNA

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bettina Thalinger ◽  
Elisabeth Wolf ◽  
Michael Traugott ◽  
Josef Wanzenböck
Keyword(s):  
Fish Species ◽  
Anthropogenic Impacts ◽  
Environmental Dna ◽  
Signal Strength ◽  
Digital Pcr ◽  
Freshwater Ecosystems ◽  
Non Invasive ◽  
River Stretch ◽  
Daily Discharge ◽  
Invasive Techniques

Abstract Potamodromous fish are considered important indicators of habitat connectivity in freshwater ecosystems, but they are globally threatened by anthropogenic impacts. Hence, non-invasive techniques are necessary for monitoring during spawning migrations. The use of environmental DNA (eDNA) potentially facilitates these efforts, albeit quantitative examinations of spawning migrations remain so far mostly uncharted. Here, we investigated spawning migrations of Danube bleak, Alburnus mento, and Vimba bream, Vimba vimba, and found a strong correlation between daily visual fish counts and downstream eDNA signals obtained from filtered water samples analysed with digital PCR and end-point PCR coupled with capillary electrophoresis. By accounting for daily discharge fluctuations, it was possible to predict eDNA signal strength from the number of migrating fish: first, the whole spawning reach was taken into account. Second, the model was validated using eDNA signals and fish counts obtained from the upper half of the examined river stretch. Consequently, fish counts and their day-to-day changes could be described via an eDNA-based time series model for the whole migration period. Our findings highlight the capability of eDNA beyond delivering simple presence/absence data towards efficient and informative monitoring of highly dynamic aquatic processes such as spawning migrations of potamodromous fish species.

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