scholarly journals Importance of considering riparian vegetation requirements for the long-term efficiency of environmental flows in aquatic microhabitats

2017 ◽  
Vol 21 (11) ◽  
pp. 5763-5780 ◽  
Author(s):  
Rui Rivaes ◽  
Isabel Boavida ◽  
José M. Santos ◽  
António N. Pinheiro ◽  
Teresa Ferreira
Keyword(s):  
Fish Species ◽  
Riparian Vegetation ◽  
Environmental Flows ◽  
Fish Habitat ◽  
Natural Habitat ◽  
River Channel ◽  
Habitat Availability ◽  
Hydraulic Characteristics ◽  
Vegetation Development

Abstract. Environmental flows remain biased toward the traditional biological group of fish species. Consequently, these flows ignore the inter-annual flow variability that rules species with longer lifecycles and therefore disregard the long-term perspective of the riverine ecosystem. We analyzed the importance of considering riparian requirements for the long-term efficiency of environmental flows. For that analysis, we modeled the riparian vegetation development for a decade facing different environmental flows in two case studies. Next, we assessed the corresponding fish habitat availability of three common fish species in each of the resulting riparian landscape scenarios. Modeling results demonstrated that the environmental flows disregarding riparian vegetation requirements promoted riparian degradation, particularly vegetation encroachment. Such circumstance altered the hydraulic characteristics of the river channel where flow depths and velocities underwent local changes of up to 10 cm and 40 cm s−1, respectively. Accordingly, after a decade of this flow regime, the available habitat area for the considered fish species experienced modifications of up to 110 % when compared to the natural habitat. In turn, environmental flows regarding riparian vegetation requirements were able to maintain riparian vegetation near natural standards, thereby preserving the hydraulic characteristics of the river channel and sustaining the fish habitat close to the natural condition. As a result, fish habitat availability never changed more than 17 % from the natural habitat.

scholarly journals Importance of considering riparian vegetation requirements for the long-term efficiency of environmental flows

2017 ◽  
Author(s):  
Rui Rivaes ◽  
Isabel Boavida ◽  
José M. Santos ◽  
António N. Pinheiro ◽  
Teresa Ferreira
Keyword(s):  
Fish Species ◽  
Riparian Vegetation ◽  
Environmental Flows ◽  
Fish Habitat ◽  
Natural Habitat ◽  
Life Cycles ◽  
River Channel ◽  
Habitat Availability ◽  
Hydraulic Characteristics

Abstract. Environmental flows remain biased toward the traditional biological group of fish species. Accordingly, these flows ignore the inter-annual flow variability that rules species with longer life cycles, thereby disregarding the long-term perspective of the riverine ecosystem. We analyzed the influence of considering riparian requirements for the long-term efficiency of environmental flows. For that analysis, we modeled the riparian vegetation development for a decade facing different environmental flows in two case studies. Next, we assessed the corresponding fish habitat availability of three common fish species in each of the resulting riparian habitat scenarios. Modeling results demonstrated that the environmental flows disregarding riparian vegetation requirements promoted riparian degradation, particularly vegetation encroachment. Such circumstance altered the hydraulic characteristics of the river channel where flow depths and velocities underwent changes up to 10 cm and 40 cm s−1, respectively. Accordingly, after a decade of this flow regime, the available habitat area for the considered fish species experienced modifications in absolute from 18.16 % to 109.75 % compared to the natural habitat. In turn, environmental flows regarding riparian vegetation requirements were able to maintain riparian vegetation near natural standards, thereby preserving the hydraulic characteristics of the river channel and sustaining the fish habitat close to the natural condition. As a result, fish habitat availability never changed more than 16.17 % from the natural habitat.

scholarly journals The inbuilt long-term unfeasibility of environmental flows when disregarding riparian vegetation requirements

2015 ◽  
Vol 12 (10) ◽  
pp. 10701-10737 ◽  
Author(s):  
R. Rivaes ◽  
I. Boavida ◽  
J. M. Santos ◽  
A. N. Pinheiro ◽  
M. T. Ferreira
Keyword(s):  
Riparian Vegetation ◽  
Environmental Flows ◽  
Fish Habitat ◽  
Flow Regimes ◽  
Environmental Flow ◽  
Life Cycles ◽  
Habitat Availability ◽  
Riparian Habitat ◽  
Fluvial Ecosystem

Abstract. Environmental flows remain biased towards the traditional fish biological group and ignore the inter-annual flow variability that rules longer species life cycles, thus disregarding the long-term perspective of the riverine ecosystem. Incorporating riparian vegetation requirements into environmental flows could bring an important contribute to fill in this gap. The long-term after-effects of this shortcoming on the biological communities downstream of dams were never estimated before. We address this concern by evaluating the effects of environmental flow regimes disregarding riparian vegetation in the long-term perspective of the fluvial ecosystem. To achieve that purpose, the riparian vegetation evolution was modeled considering its structural response to a decade of different environmental flows, and the fish habitat availability was assessed for each of the resulting riparian habitat scenarios. We demonstrate that fish habitat availability changes accordingly to the long-term structural adjustments that riparian habitat endure following river regulation. Environmental flow regimes considering only aquatic biota become obsolete in few years due to the change of the habitat premises in which they were based on and, therefore, are unsustainable in the long run. Therefore, considering riparian vegetation requirements on environmental flows is mandatory to assure the effectiveness of those in the long-term perspective of the fluvial ecosystem.

Polyculture in fish farming as a method of preventing fish diseases

2021 ◽  
pp. 30-40
Author(s):  
Grigory Emelyanovich Servetnik
Keyword(s):  
Fish Species ◽  
Fish Habitat ◽  
Fish Farming ◽  
Natural Food ◽  
Total Biomass ◽  
Fish Farms ◽  
Fish Diseases ◽  
Host Body ◽  
Contagious Diseases

Methods of prevention of fish diseases are aimed at destroying parasites in the host body and in the fish habitat — in the reservoir (chemoprophylaxis, increasing fish resistance), at preventing parasites from entering the reservoir (limiting the import of fish, import of healthy fish, quarantine measures, etc.), as well as preventing their spread and entry into the host body. It is shown that polyculture is not only the most effective method of using the natural forage base of the reservoir and, as a result, increasing fish productivity, but also a means of preventing mass infectious and other fish diseases. To prevent mass infectious diseases of fish and death from them both in safe and unfavorable ponds of carp fish farms, it is advisable to grow other fish species together with carp that do not suffer from diseases peculiar to carp. As a result, so-called sparse species plantings of fish are created in the ponds, while the total biomass remains high. At the same time, the natural food supply of ponds is most fully used and a kind of biological buffer is created that prevents the emergence and spread of contagious diseases. Polyculture can play a particularly important role in pond farms that already have certain problems with rubella, filometroidosis, botryocephalosis, carp pox, etc. Long-term studies of breeding herds in pond farms have shown that most of them have single foci of diseases, which, if there are optimal conditions for the pathogen, are ready to immediately respond with an outbreak of the disease or are generally quarantined for a particular fish disease. When determining the objects of polyculture, it is necessary to reduce the proportion of fish species that have a significant number of common diseases.

scholarly journals Characterization of the Fish Population in the Southwestern Part of the Onega Lake (Karelia) Based on the Results of Long-Term Monitoring

2020 ◽  
Vol 8 (4) ◽  
pp. 1510-1515
Keyword(s):  
Fish Species ◽  
Fish Habitat ◽  
Fish Population ◽  
The Arctic ◽  
Coregonus Lavaretus ◽  
Southwestern Part ◽  
Onega Lake ◽  
Late Tertiary ◽  
Commercial Species

The results of the long-term ichthyological studies of the southwestern part (the Sheltozero – Brusno region) of the Onega Lake performed as part of the environmental monitoring have been presented. This is one of the most productive and clean areas in the lake. The fish population of the southwestern part of the Onega Lake includes 20 fish species that are representatives of 10 families belonging to six faunistic complexes. By the number of the species, the Carp family dominates. By the number of the species in this area of the lake, the Arctic freshwater, the boreal plain, and the boreal foothill complexes are equally important. The species of the freshwater Pontian, the Arctic marine, and the ancient Late Tertiary complexes together amount to no more than 25 % of the total population. In the southwestern region of the lake, there are many valuable commercial species (freshwater salmon (Salmo salar Linnaeus, 1758), lavaret (Coregonus lavaretus lavaretus (Linnaeus, 1758)), pikeperch (Sander lucioperca (Linnaeus, 1758)), pike (Esox lucius Linnaeus, 1758), etc. Smelt (Osmerus eperlanus (Linnaeus, 1758)) and vendace (Coregonus albula (Linnaeus, 1758)) are the most commercially valuable (75 – 85 %). The population-ecological analysis has shown a relatively good state of most studied fish species. For maintaining the existing structure and state of the fish population in the southwestern part of the Onega Lake, a set of measures is required, including the preservation and improvement of the fish habitat, the conditions for the fish reproduction and feeding; toughening the protective measures during periods with a decrease in the number of fish species; regulation of fishing, and increasing the amount of fish artificial reproduction, rearing, and releasing into the lake.

scholarly journals Using CASIMIR-VEGETATION Model in the context of modeling riparian woods and fish species to support a holistic approach for environmental flows to be used on river management and conservation

2016 ◽  
Vol 4 (1) ◽  
pp. 01
Author(s):  
Rui Pedro Rivaes ◽  
António Nascimento Pinheiro ◽  
Gregory Egger ◽  
Maria Teresa Ferreira
Keyword(s):  
Flow Regime ◽  
Fish Species ◽  
Riparian Vegetation ◽  
Environmental Flows ◽  
Holistic Approach ◽  
Physical Processes ◽  
Vegetation Model ◽  
Flow Response ◽  
The Relationship ◽  
Management And Conservation

<p>The CASiMiR-vegetation model is a software that recreates the physical processes influencing the survival and recruitment of riparian vegetation, based on the relationship between ecologically relevant flow regime components and riparian vegetation metrics that reflect the vegetation’s responses to flow regime change. Working at a flow response guild level, this tool outperforms equivalent models by overriding various restrictions of the conventional modeling approaches. The potential of the CASiMiR-vegetation model is revealed in its application to different case studies during the development of a holistic approach to determine environmental flows in lowland Mediterranean rivers, based on woody riparian vegetation and fish species. Various modeling circumstances are described where CASiMiR-vegetation model was used with the purpose of sustaining the research addressing the thesis objectives. The main findings already accomplished in this research are highlighted to illustrate the outcomes that can be attained from the use of such a model.</p>

SEEDING DENSITY OF DIFFERENT FISH SPECIES IN POLYCULTURE

2017 ◽  
pp. 74-79
Author(s):  
Yuriy Borisovich Lvov
Keyword(s):  
Fish Species ◽  
Silver Carp ◽  
Seeding Density ◽  
Habitat Conditions ◽  
Method Of Calculation ◽  
Fish Breeding ◽  
Trophic Preferences ◽  
Breeding Zone ◽  
Practical Progress

The article touches upon the principles, biological basics and practical progress of introduction of specific and age polyculture of fishes. Using the results of the analysis of literary and long-term native data, there has been offered the gradation of 12 fish species from different families by resistance to habitat conditions. Crucian ( Carassius gibelio ) has been chosen as the most sustainable object of cultivation. There has been taken an attempt to calculate the number of seeding different fish species in polyculture taking into account their physiological features is made. Subject to specific physiological features of the studied species, there was carried out recalculation of their natural reproductive performance in different fish-breeding zones, which is traditionally carried out for a carp ( Cyprinus carpio ). In particular, in the second fish-breeding zone with area of 1 hectare it is possible to breed 120 kg of carp, or 150 kg of crucian, or 75 kg of silver carp ( Hypophthalmichthys ). Overall productivity is made up of a share of fishes in polyculture, but taking into account tolerance of species, it can be lower than productivity calculated for carp. The method of calculation and formulas which give the chance to determine seeding density of fish species for breeding in polyculture have been offered. This technique makes it possible to use trophic preferences and consider tolerance of each species to the conditions of breeding areas.

scholarly journals Short- and long-term movement patterns of six temperate reef fishes (Families Labridae and Monacanthidae)

1995 ◽  
Vol 46 (5) ◽  
pp. 853 ◽  
Author(s):  
NS Barrett
Keyword(s):  
Natural Habitat ◽  
Movement Patterns ◽  
Reef Fishes ◽  
Long Term Results ◽  
Home Ranges ◽  
Temperate Reef ◽  
Effective Deterrent ◽  
Short And Long Term ◽  
Natural Boundaries

Movement patterns were studied on a 1-ha isolated reef surrounding Arch Rock in southern Tasmania. Short-term movements were identified from diver observations, and interpretation of long-term movements involved multiple recaptures of tagged individuals. Visual observations indicated that the sex-changing labrids Notolabrus tetricus, Pictilabrus laticlavius and Pseudolabrus psittaculus were all site-attached, with females having overlapping home ranges and males being territorial. In the non-sex-changing labrid Notolabrus fucicola and in the monacanthids Penicipelta vittiger and Meuschenia australis, there was no evidence of territorial behaviour and 1-h movements were in excess of the scale of the study. The long-term results indicated that all species were permanent reef residents, with most individuals of all species except M. australis always being recaptured within a home range of 100 m × 25 m or less. Only 15% of individuals of M. australis were always recaptured within this range category. The natural habitat boundary of open sand between the Arch Rock reef and adjacent reefs appeared to be an effective deterrent to emigration. The use of natural boundaries should be an important consideration in the design of marine reserves where the aim is to minimize the loss of protected species to adjacent fished areas.

Modelling the effects of establishing a marine reserve for mobile fish species

2002 ◽  
Vol 59 (3) ◽  
pp. 405-415 ◽  
Author(s):  
P Apostolaki ◽  
E J Milner-Gulland ◽  
M K McAllister ◽  
G P Kirkwood
Keyword(s):  
Fish Species ◽  
Marine Reserve ◽  
High Mobility ◽  
Merluccius Merluccius ◽  
Seasonal Movements ◽  
Stock Biomass ◽  
Spawning Stock ◽  
Short And Long Term ◽  
Immature Fish

We present a model of the effects of a marine reserve on spawning stock biomass (SSB) and short- and long-term yield for a size-structured species that exhibits seasonal movements. The model considers the effects of protecting nursery and (or) spawning grounds under a range of fishing mortalities and fish mobility rates. We consider two extremes of effort redistribution following reserve establishment and analyze the effects of a reserve when the fishery targets either mature or immature fish. We apply the model to the Mediterranean hake (Merluccius merluccius) and show that a marine reserve could be highly beneficial for this species. We demonstrate benefits from reserves not just for overexploited stocks of low-mobility species, but also (to a lesser extent) for underexploited stocks and high-mobility species. Greatly increased resilience to overfishing is also found in the majority of cases. We show that a reserve provides benefits additional to those obtained from simple effort control. Benefits from reserves depend to a major extent on the amount of effort redistribution following reserve establishment and on fishing selectivity; hence, these factors should be key components of any evaluation of reserve effectiveness.

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