scholarly journals Fish-food interaction network around cage fish farming in a neotropical reservoir

2021 ◽  
Vol 33 ◽  
Author(s):  
Heleno Brandão ◽  
Denise Lange ◽  
Daniel Rodrigues Blanco ◽  
Igor Paiva Ramos ◽  
Jamile Queiroz de Sousa ◽  
...  
Keyword(s):  
Fish Species ◽  
Interaction Network ◽  
Fish Farming ◽  
Food Interaction ◽  
Monthly Basis ◽  
Fish Food ◽  
Food Items ◽  
Network Methods ◽  
Iheringichthys Labrosus ◽  
Cage Fish

Abstract: Aim Investigating whether wild fish accept residual ration from cage fish farming to the point of changing their diet and the fish-food interaction network. Methods The diet of fish species, Astyanax lacustris, Iheringichthys labrosus, Leporinus amblyrhynchus, Schizodon nasutus and Steindachnerina insculpta, bred in Chavantes Reservoir, Upper Paraná basin, was evaluated. Samples were collected on a monthly basis - from March 2008 to February 2009 - around the cage fish farming (NC) and in a reference site (RS) free from the influence of the fish farming activity. Results were analyzed through graphs and metrics of complex network analysis, and Permutational analysis of variance. Results The total number of 641 individuals belonging to all five fish species were collected, 292 in NC and 349 in RS. The total amount of food items consumed by them comprised 24 items in NC and 22 items in RS. The fish-food interaction network has shown nested pattern in the two evaluated areas, which evidenced the generalist structure of this interaction. Connectance values and mean degree of interaction networks were low. Detritus was the most representative item consumed in both sampling sites. Three of the five evaluated species (A. lacustris, S. nasutus and I. labrosus) had residual ration in their diet. Residual ration was the fourth most consumed item in NC. It was also the most representative food item for A. lacustris and S. nasutus. Conclusions Results have shown that cage fish farming activity can influence trophic interactions in aquatic systems, as well as evidenced the ability of S. nasutus, L. labrosus and A. lacustris to take advantage of new food items in their environment.

scholarly journals Effect of production quotas on economic and environmental values of growth rate and feed efficiency in sea cage fish farming

PLoS ONE ◽  
2017 ◽  
Vol 12 (3) ◽  
pp. e0173131 ◽  
Author(s):  
M. Besson ◽  
I. J. M. de Boer ◽  
M. Vandeputte ◽  
J. A. M. van Arendonk ◽  
E. Quillet ◽  
...  
Keyword(s):  
Growth Rate ◽  
Feed Efficiency ◽  
Fish Farming ◽  
Environmental Values ◽  
Sea Cage ◽  
Cage Fish

scholarly journals Influence of net-cage fish farming on zooplankton biomass in the Itá reservoir, SC, Brazil

2012 ◽  
Vol 23 (4) ◽  
pp. 357-367 ◽  
Author(s):  
Bruna Roque Loureiro ◽  
Christina Wyss Castelo Branco ◽  
Evoy Zaniboni Filho
Keyword(s):  
Fish Farming ◽  
Dry Weight ◽  
Control Area ◽  
Zooplankton Biomass ◽  
Total Density ◽  
Total Zooplankton ◽  
Net Cage ◽  
Uruguay River ◽  
Cage Fish ◽  
Total Zooplankton Biomass

OBJECTIVES: This study aimed to verify the influence of net-cage fish farming on zooplankton biomass in the Itá reservoir (Uruguay River, Brazil). METHODS: Samples were collected monthly from October/2009 to May/2010 at the surface and at the bottom in two sampling stations, the net-cage area and in a control area using a Van Dorn bottle and a plankton net (68 µm). RESULTS: The Cladocera and Copepoda biomass was estimated by dry weight using a micro-analytical balance, and the Rotifera biomass by Biovolume. Total zooplankton biomass varied between 6.47 and 131.56 mgDW.m-3 Calanoida copepod presented the highest value of biomass (127.56 mgDW.m-3) and rotifers, despite having an important contribution to total density, showed a maximum biomass of 2.01 mgDW.m-3. Zooplankton biomass at the net-cage area surface was higher when compared with the control area during the months of October to January. However, the zooplankton biomass was similar at the bottom of the two areas throughout the studied period. From February until May, zooplankton biomass decreased in both sampling stations, a fact probably associated with the flushing of the reservoir, followed by an increase in water transparency and a decrease in chlorophyll-a concentration in the following months (February to May). CONCLUSIONS: The influence of fish farming on zooplankton biomass was detected at the surface of the net-cage area only from October to January. From February to May this influence was not found, probably by the influence of the flushing of the reservoir.

scholarly journals Analysis of reproductive biology and spawning season of the pink ear emperor Lethrinus lentjan, from marine ecosystem

2020 ◽  
Vol 37 ◽  
pp. 1-10
Author(s):  
Elsayed M. Younis ◽  
Nasser A. Al-Asgah ◽  
Abdel-Wahab A. Abdel-Warith ◽  
Mohamed H. Gabr ◽  
Fozi S. Shamlol
Keyword(s):  
Fish Species ◽  
Gonadosomatic Index ◽  
Marine Ecosystem ◽  
Local Population ◽  
Spawning Season ◽  
Monthly Basis ◽  
Population Sampling ◽  
Maturation Rate ◽  
Maturation Index ◽  
One Year

A total of 593 samples of Lethrinus lentjan (Lacepede, 1802) were collected from the Red Sea, Jeddah, Saudi Arabia, to study their productive biology and spawning season of the local population. Sampling was carried out on a monthly basis for a period of one year. The monthly sex ratios indicated that females were dominant throughout the study period, with an overall male:female sex ratio of 1:7.98, although males were larger than females. The highest monthly performance maturation index (PMI), as well as the male and female gonadosomatic index (GSI) and ovarian maturation rate (OMR) were observed in February and March. Histological examination of the gonads confirmed the process of sexual transformation in this fish species, wherein individuals mature first as female, and then change sex to male (protogynous hermaphroditism). Histological sections also showed that the sexual maturation of males of L. lenjtan comprised three main stages, while the sexual development of females could be classified into four main stages. Extended spawning in the form of batches released during different months throughout the year were recorded for this fish species, with the main spawning season in February and March, and an additional, shorter spawning season in September.

scholarly journals Length-Weight Relationships and Condition Factors of Three Tilapine Species in an Abandoned Gold Mine Reservoir, Igun, Southwestern Nigeria

2019 ◽  
Vol 11 (2) ◽  
pp. 205-209
Author(s):  
Oluwadamilare E. OBAYEMI ◽  
Olusola O. KOMOLAFE ◽  
Oluwakemi V. OKUNOLA ◽  
Sakirat T. ASAFA ◽  
Mary A. AYOADE
Keyword(s):  
Fish Species ◽  
Oreochromis Niloticus ◽  
Condition Factor ◽  
Gold Mine ◽  
Southwestern Nigeria ◽  
Monthly Basis ◽  
B Values ◽  
Total Length ◽  
The Mean ◽  
Sarotherodon Galilaeus

This study investigated the length-weight relationships and condition factors of three fish species in an abandoned gold mine reservoir. The fishes were caught on monthly basis between August 2015 and July 2016 using gill nets and traps. The results showed that Coptodon zillii, Oreochromis niloticus and Sarotherodon galilaeus had a mean total length and mean weight of 15.52±4.64 cm and 95.80±66.27 g; 15.27±4.18 cm and 89.54±63.20 g; 15.57±4.80 cm and 102.0±85.81 g respectively. Also, the mean condition factor obtained for the fish species are 2.24±0.52 in C. zillii; 2.26±0.62 in O. niloticus and 2.27±0.46 in S. galilaeus. Similarly, the slope (b) values and correlation coefficient for the three fish species are 2.018 and 0.969 for C. zillii; 1.977 and 0.926 for O. niloticus and 2.436 and 0.965 for S. galilaeus. Furthermore, the total length, weight and condition factor between C. zillii, O. niloticus and S. galilaeus differ significantly (p>0.05). The study concluded that despite being an abandoned gold mine reservoir, the environment is well suitable for the fishes.

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.

Impact of cage culture in reservoir on the livelihood of fishers: A case study in Jharkhand, India

2021 ◽  
Vol 68 (1) ◽  
Author(s):  
Arun Pandit ◽  
B. K. Das ◽  
Ganesh Chandra ◽  
Aparna Roy ◽  
Piyashi Debroy ◽  
...  
Keyword(s):  
Family Income ◽  
Low Cost ◽  
Market Price ◽  
Fish Farming ◽  
The State ◽  
Cage Culture ◽  
Pangasianodon Hypophthalmus ◽  
High Feed ◽  
High Initial Cost ◽  
Cage Fish

Cage fish farming in Indian reservoirs has the potential to enhance the reservoir production manifold. The present study estimated that around 14,000 cages have been installed in different reservoirs of the country which are producing around 16% of the current reservoir fish production. Around 7.5 lakh mandays of labour are being generated by cage fish farming in the country. An empirical study in the state of Jharkhand State found that the adoption of cage culture contributed around 30% to the livelihood of fishers. Cage culture not only increased monthly family income but also reduced the occupational migration. The fishermen households who adopted cage farming also accumulated some durable assets due to improvement in household income. However, high initial cost of cage culture operation, high feed cost and low market price of cultured pangas fish (Pangasianodon hypophthalmus) were some of the major constraints in adopting the technology as reported by the fishers. The study recommends that the state departments need to promote the use of low cost galvanised iron(GI) cages designed by the ICAR-Central Inland Fisheries Research Institute (ICAR-CIFRI) in reservoirs which may play a significant role in fulfilling the vision of blue revolution in the country.

Influence of some physico-chemical variables on wild fish richness beneath sea-cage fish farms in the Aegean Sea, Turkey

2020 ◽  
Vol 100 (7) ◽  
pp. 1171-1179
Author(s):  
Okan Akyol ◽  
Aytaç Özgül ◽  
F. Ozan Düzbastılar ◽  
Halil Şen ◽  
José M. Ortiz de Urbina ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Fish Assemblages ◽  
Wild Fish ◽  
Light Transmittance ◽  
Fish Farms ◽  
Physico Chemical ◽  
Sea Cage ◽  
The Relationship ◽  
Cage Fish

AbstractThis study aims to determine the relationship between physico-chemical variables on a seasonal basis and wild fish assemblages beneath sea-cage fish farms. Assemblages of wild fish were counted monthly on two separate days at each of six fish farms between August 2015 and July 2017, by six rapid visual counts (RVC) in 5 minutes with scuba by two divers. Seawater samples were simultaneously taken by a Nansen bottle during the RVC from the fish farm barge. SST (°C), salinity (ppm), dissolved oxygen (mg l−1) and pH were measured by YSI multiparameter, while Secchi disk was also used for light transmittance. Wild fish species richness went up with increasing temperature and salinity in the Izmir region, however, this stopped at about 26°C and about 39 ppm. Wild fish richness increased when the DO was at a level of 7 mg l−1 and the pH at about 7.9 in Izmir. Between 10 and 20 m, light transmittance showed greater wild fish species richness in Izmir region. In contrast, the wild fish species richness of the Muğla region fluctuated more. In terms of wild fish species richness, these fluctuations increased with salinity and DO, while they decreased with SST, pH and light transmittance. However, the range of variation of the recorded physico-chemical variables is rather narrow. The results of the correlation matrix indicate that the relationship between wild fish species richness and pH and SST was statistically significant in Izmir region (P < 0.05).

scholarly journals Ecomorphology and food habits of teleost fishes Trachinotus carolinus (Teleostei: Carangidae) and Menticirrhus littoralis (Teleostei: Sciaenidae), inhabiting the surf zone off Niterói, Rio de Janeiro, Brazil

2010 ◽  
Vol 58 (spe4) ◽  
pp. 1-9 ◽  
Author(s):  
Luana Prestrelo Palmeira ◽  
Cassiano Monteiro-Neto
Keyword(s):  
Fish Species ◽  
Food Habits ◽  
Diet Composition ◽  
Surf Zone ◽  
Fish Larvae ◽  
Sandy Beaches ◽  
Size Class ◽  
Class I ◽  
Teleost Fishes ◽  
Food Items

The ecomorphology and food habits of juvenile Trachinotus carolinus and Menticirrhus littoralis caught in the surf zone of sandy beaches in Niterói, RJ, were investigated between July 2006 and May 2007. These fish species differ morphologically, but present similarities in their diet composition suggest some slight overlapping in their diet. The importance of food items was assessed using Kawakami and Vazzoler's feeding index. Morphometric variables were recorded to correlate with the diet composition of the different size classes for each species. A total of 210 fishes (Trachinotus carolinus - 122, Menticirrhus littoralis - 88), ranging between 24.2 mm and 112 mm total length, were analyzed, but the stomachs of only 84.8% of them contained food. Trachinotus carolinus presented mysids, Polychaetes and Emerita spp. as the predominant items in their diet. Formicidae and Isopoda were the most important items for class I individuals, whereas mysids and Emerita spp. were important for classes II and III. Class I individuals also showed smaller sized prey (amphipods and isopods) and clupeid fish larvae in their diet. Emerita spp. dominated the food items of Menticirrhus littoralis regardless of the size class. Polychaetes, the second most important item was better represented in class sizes II and III. The main morphometric variable correlated with such differences included mouth position and diameter of the eye.

scholarly journals Assessment of the Presence of Total Aflatoxins and Aflatoxin B1 in Fish Farmed in Two Cameroonian Localities

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Julie J. Tsafack Takadong ◽  
Hippolyte T. Mouafo ◽  
Linda Manet ◽  
Annick M. B. Baomog ◽  
Jorelle J. B. Adjele ◽  
...  
Keyword(s):  
Fish Species ◽  
Fish Farming ◽  
Threshold Value ◽  
Fish Tissue ◽  
Competitive Elisa ◽  
Elisa Method ◽  
Fish Feeds ◽  
Aflatoxin B ◽  
State Of Art

This work aimed at assessing the presence of total aflatoxins (AFs) and aflatoxin B1 (AFB1) in fish farmed in two Cameroonian localities and the possible origin of that contamination through analysis of fish feeds as well as water and mud collected from the fish farming ponds. Four fish species (kanga, tilapia, catfish, and carp) were collected from two fish farming sites (Mfou and Batié). Mud and water from the farming ponds of the different species and the fish feeds used in these sites were also collected. The samples (34) were analyzed for their levels of AFs and AFB1 using the competitive ELISA method. The results obtained showed that all fish tissue contained AFs and AFB1. A level of AFs higher than the threshold value recommended by the FDA (20 ppb) was observed in catfish (31.38±0.29 ppb). AFs and AFB1 were presented in fish feeds as well as in muds collected from the farming ponds. Catfish was the fish species which mostly bioaccumulated aflatoxins in their tissue. This study presents the state of art on the mycotoxin contamination of fish farmed in some Cameroonian localities and suggests that attention should be paid to the quality of ingredients used to feed fish.

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