The planocerid flatworm is a main supplier of toxin to tetrodotoxin-bearing fish juveniles

Chemosphere ◽  
2020 ◽  
Vol 249 ◽  
pp. 126217 ◽  
Author(s):  
Shiro Itoi ◽  
Tatsunori Sato ◽  
Mitsuki Takei ◽  
Riko Yamada ◽  
Ryuya Ogata ◽  
...  
Keyword(s):  
Fish Juveniles

THE NUMBER AND QUALITATIVE CHARACTERISTICS OF FRY FISH IN SHALLOW COASTAL WATERS OF THE VOLGA IN THE SUMMER-AUTUMN PERIOD OF 2012

2017 ◽  
pp. 65-73
Author(s):  
Edward Vladimirovich Nikitin
Keyword(s):  
Fish Species ◽  
Coastal Waters ◽  
Caspian Sea ◽  
The Caspian Sea ◽  
Volga River ◽  
Commercial Fish ◽  
Autumn Period ◽  
Fish Juveniles ◽  
Qualitative Characteristics ◽  
Shallow Coastal Waters

Shallow coastal waters of the Volga river is a flooded feeding area for fish juveniles of nonmigratory fish species. There takes place annual downstream migration of fluvial anadromous fish species from spawning grounds of the Volga river to the Northern Caspian Sea. The most important factors determining the number and qualitative characteristics of fry fishes are the level of the Caspian Sea (currently having a tendency to the lowering), hydrological and thermal regimes of the Volga river. Researches were carried out in definite periods of time. In the summer-autumn period of 2012 fry fishes were presented by 19 species (13 of them were commercial species), which belonged to 9 families. The article gives data on all the commercial fish species. In the first decade of July the maximum number of fry fish was registered in the western part of the Volga outfall offshore - in box 247 (19.86 mln specimens/km2), in the eastern part - in box 142 (20.4 mln specimens/km2). The most populous were roach, red-eye, silver bream and bream; size-weight characteristics were better in the areas remoted from the Volga delta. In the third decade of July the quantitative indicators of fry fish on these areas decreased, size-weight characteristics greatly increased. In the second decade of October in the western part of the seaside there were registered increased pre-wintering concentrations of fish juveniles, their qualitative indicators increased, which is evidence to favorable feeding conditions in 2012.

Spatiotemporal distribution of nocturnal coral reef fish juveniles in Moorea Island, French Polynesia

2007 ◽  
Vol 54 (1) ◽  
pp. 18-23 ◽  
Author(s):  
David Lecchini ◽  
Yohei Nakamura ◽  
Makoto Tsuchiya ◽  
René Galzin
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Coral Reef Fish ◽  
French Polynesia ◽  
Spatiotemporal Distribution ◽  
Fish Juveniles ◽  
Moorea Island

scholarly journals Peningkatan Pertumbuhan Ikan Nila (Oreochromis niloticus) Melalui Pemberian Immunostimulan Ragi Roti (Saccharomyces cereviciae)

2014 ◽  
Vol 2 (3) ◽  
Author(s):  
Achmad A Bugis ◽  
Henky Manoppo
Keyword(s):  
Oreochromis Niloticus ◽  
Optimal Growth ◽  
Baker’S Yeast ◽  
Fish Growth ◽  
Average Weight ◽  
Baker's Yeast ◽  
Study Program ◽  
Fish Food ◽  
Relative Growth ◽  
Fish Juveniles

This research aimed to examine the effect of baker’s yeast as immunostimulant on growth of nile tilapia and to find out a proper dose of baker’s yeast that promoted optimal growth of fish. Juveniles with an average weight of 31.83 g were obtained from stock available at Aquaculture Study Program of the Faculty of Fisheries and Marine Sciences.  This research was conducted at the experimental ponds located at the Faculty of Fisheries and Marine Sciences for three months. During the experiment, fish was fed with pellet supplemented with baker’s yeast as treatment for four weeks as much as 4%/bw/day, twice daily.  The doses of baker’s yeast consisted of 0, 10, 20, 30, and 40 g/kg pellet. Fish growth including absolute and relative growth was measured at two weeks interval.  Research results showed that  after two weeks of feeding, supplementation of baker’s yeast did not affect the growth of fish but after four weeks of feeding, supplementation of baker’s yeast significantly increased fish growth. Fish fed pellet supplemented with 10 g baker’s yeast displayed the highest growth. As conclusion, supplementation of baker’s yeast in fish food could enchance the growth of fish.   Keywords:  Oreochromis niloticus, immunostimulant, baker’s yeast, growth

Management implications of juvenile reef fish habitat preferences and coral susceptibility to stressors

2010 ◽  
Vol 61 (5) ◽  
pp. 532 ◽  
Author(s):  
Edward E. DeMartini ◽  
Todd W. Anderson ◽  
Jean C. Kenyon ◽  
James P. Beets ◽  
Alan M. Friedlander
Keyword(s):  
Coral Bleaching ◽  
Fish Habitat ◽  
Habitat Preferences ◽  
Reef Fishes ◽  
Relative Susceptibility ◽  
Rugose Corals ◽  
Fish Juveniles ◽  
Juvenile Reef Fish ◽  
Juvenile Stages ◽  
Ecological Importance

In the Hawaiian Archipelago, shelter-dependent juvenile stages of many reef fishes and their coral habitats are increasingly put at risk by multiple anthropogenic stressors (e.g. overfishing and habitat loss, coral bleaching and sedimentation, respectively). We assessed coral bleaching (to identify relative susceptibility among growth forms) and the use v. availability of structurally complex and simple corals by juvenile reef fishes in Hawai'i. We use these data in a model that identifies habitats and resource species for managing reef fisheries and conserving coral habitats. Many juvenile reef fishes preferentially inhabit rugose corals. The economic and ecological importance of these fishes varies from those with little value to others, such as highly prized parrotfishes that also serve as ecological engineers. Coral species also differ in their relative susceptibility to anthropogenic and natural stressors – more structurally complex corals tend to be more susceptible to stressors. Our model relates the economic and ecological valuations of fish resources with specific preferences of fish juveniles for corals of varying susceptibility, testing the prediction that risk should co-vary among species of corals and fishes. Managers should use such a model when prioritising habitats and resource species for conservation.

Importance of intertidal seagrass beds as nursery area for coral reef fish juveniles (Mayotte, Indian Ocean)

2020 ◽  
Vol 33 ◽  
pp. 100965 ◽  
Author(s):  
Rakamaly Madi Moussa ◽  
Frederic Bertucci ◽  
Hendrikje Jorissen ◽  
Camille Gache ◽  
Viliame Pita Waqalevu ◽  
...  
Keyword(s):  
Coral Reef ◽  
Indian Ocean ◽  
Reef Fish ◽  
Coral Reef Fish ◽  
Nursery Area ◽  
Seagrass Beds ◽  
Fish Juveniles ◽  
Intertidal Seagrass

Fishes of a shallow tropical mangrove estuary, Gazi, Kenya

1996 ◽  
Vol 47 (7) ◽  
pp. 857 ◽  
Author(s):  
EN Kimani ◽  
GK Mwatha ◽  
EO Wakwabi ◽  
JM Ntiba ◽  
BK Okoth
Keyword(s):  
Diversity Indices ◽  
Ecological Diversity ◽  
Muddy Sand ◽  
Beach Seine ◽  
Commercial Fish ◽  
Mangrove Estuary ◽  
Fish Juveniles ◽  
The Mean ◽  
Sandy Substratum ◽  
Density And Biomass

The composition and abundance of teleosts in an estuarine mangrove bay, sampled with a beach seine-net, are described. Site 1, at the mouth of a small river, was fringed by mangroves and had a silty substratum; Site 2 was also mangrove-fringed but had a sandy substratum and seagrass patches; Site 3 had a muddy sand substratum and also supported seagrasses. In total, 128 teleost species belonging to 50 families were identified in samples collected over 12 months. Gerreidae, Atherinidae and Clupeidae accounted for 78.5% of the total number of fish. Juveniles were found for 63% of the species. Of the fish species found, 44% were species associated with coral reefs. The mean numbers of species were similar at all sites, despite the differences in substratum type. Ecological diversity indices were higher, and fish density and biomass were lower, in the mangrove-fringed silt site than in the seagrass sites. Mean number of species was highest in February and June. Most families of commercial fish sought by fishers in the area were represented in the samples.

scholarly journals Feeding and food supply of juvenile fishes in the eastern Bering Sea in 2003-2012

2015 ◽  
Vol 181 (2) ◽  
pp. 129-140
Author(s):  
Natalia A. Kuznetsova
Keyword(s):  
Bering Sea ◽  
Cold Water ◽  
Walleye Pollock ◽  
Feeding Intensity ◽  
Sand Lance ◽  
Food Ration ◽  
Eastern Bering Sea ◽  
Fish Juveniles ◽  
Calanus Marshallae ◽  
Atka Mackerel

Feeding of fish juveniles in the eastern Bering Sea is investigated for the periods of 2003-2006 considered as relatively «warm» and 2007-2012 considered as relatively «cold». Small- and medium-sized zooplankton was the dominant prey in the 2003-2006, in particular copepods prevailed in the food of walleye pollock (41.5 %), pacific herring (48.3 %), and sand lance (71.7 %) juveniles, which in turn were the prey for pollock, herring and cod yearlings and other predators. On the contrary, large-sized zooplankton was more abundant in the 2007-2012, so arrowwarms ( Sagitta sp.), large-sized copepods (in particular Calanus marshallae ), euphausiids (mainly Thysanoessa raschii ), hyperiids, and pteropods were the prey for young fish: C. marshallae - for juveniles of pollock (40-45 % by weight) and capelin (32-34 %), Th. raschii - for yearlings of pollock (51 %) and herring (36-46 %), cold-water hyperiid T. libellula - for adult pollock (24 %), juvenile cod (9-18 %) and juvenile herring (9-11 %), whereas portion of fish in the diets was insignificant. In the warm period (2003-2006), juvenile pollock, herring, sand lance and capelin were zooplankton-eaters with the diets similarity 67 %, while yearlings of pollock and juveniles of cod, herring, sandfish, and atka mackerel were fish-eaters preying upon pollock juveniles. In the cold period (2007-2012), the diets of juvenile pollock, juvenile and adult capelin, and juvenile sand lance were also similar at 85-70 % but they preferred large-sized copepods and euphausiids ( C. marshallae and Th. raschii ), while yearlings of pollock, yearlings and adults of herring, and juveniles of sand fish and cod had the diets of 70 % similarity with Th. raschii prevalence. Feeding intensity was high for all species: the mean stomach fullness was 150-200 ‱ for pollock juveniles and yearlings, 200-250 ‱ for cod juveniles, 200-258 ‱ for sand lance juveniles, 302 ‱ for herring juveniles, and 178-250 ‱ for juvenile atka mackerel. The fullness had diurnal rhythm with three peaks: at noon - up to 179 ‱, in evening - up to 213 ‱, and at night - up to 204 ‱ (the data for walleye pollock juveniles in «cold» years only). Daily food ration of juvenile pollock is estimated as 6.7 % of its body weight in the «warm» years and 7.0 % in the «cold» years.

scholarly journals NEGATIVE ANTHROPOGENIC INFLUENCE OF COOLING SYSTEMS OF POWER PLANTS AND WAYS OF ITS OVERCOMING

2020 ◽  
pp. 193-201 ◽  
Author(s):  
Nadezhda K. Fedorovskaya
Keyword(s):  
Heat Sink ◽  
Power Plants ◽  
Food Chains ◽  
Anthropogenic Influence ◽  
Cooling Systems ◽  
Fish Resources ◽  
Fish Juveniles ◽  
The Impact ◽  
Intake Water

The issues of the impact of the cooling systems of ship power plants on the fish resources of the seas and continental reservoirs are considered. Widespread open cooling systems consume intake water. The filters used are not capable of trapping plankton and fish juveniles. As a result, when passing through the system, they die almost completely. Consequently food chains are destroyed and the fish resources of the seas are reduced. Numerical estimates of the damage are given. It is shown that the problem can be solved by introducing closed cooling systems. The necessary methods for increasing the heat sink of systems have been developed. As a result, it becomes possible to significantly reduce the weight and dimensions of the systems, which contributes to their implementation in practice.

scholarly journals Estimation of natural reproduction efficiency of semi-anadromous and river fish species in inland water bodies of the Republic of Dagestan, Russia

2020 ◽  
Vol 15 (3) ◽  
pp. 31-42
Author(s):  
A. S. Abdusamadov ◽  
E. A. Akhmaev ◽  
A. A. Latunov ◽  
T. A. Abdusamadov ◽  
A. K. Butaeva ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Juvenile Fish ◽  
Relative Proportion ◽  
Water Bodies ◽  
Migration Routes ◽  
Inland Water ◽  
Natural Reproduction ◽  
Fish Juveniles ◽  
Inland Water Bodies ◽  
Reproduction Efficiency

Aim. Estimation of the natural reproduction efficiency and patterns of formation of fish stocks.Material and Methods. Collection of material was carried out in 2010-2019 in inland water bodies in Dagestan and its shallow Caspian Sea coastal zone. Estimation of the number of juveniles in rivers and canals was carried out using ichthyoplankton cone seines. Fry seines were used to count juveniles of fish in water bodies and in the coastal area. 470 samples of juveniles were collected and 5640 juveniles were analysed. The collection and processing of materials were carried out according to generally accepted methods.Results. The main environmental factors determining the productivity of fish juveniles in the study area in the long-term have been identified. During the observation period, juvenile fish of 15 species were recorded in spawning grounds of inland water bodies. Roach, bream, carp, crucian carp, rudd and vimba bream dominate. In terms of numbers, roach juveniles predominate: their relative proportion being 31.02% with an increase from 27.1% in 2010 to 35.4% in 2018.The second place was occupied by bream juveniles, whose average relative proportion was 12.1%. The third place was occupied by carp juveniles with an average proportion of 9%. Juvenile zander, catfish, pike and kutum are relatively low in abundance from 2 to 4%. The yield of juvenile fish in 2010-2019 decreased 1.7 times compared to 1990-1995.Conclusion. It was established that a decrease in the number of juvenile fishes occurs under the influence of unfavorable environmental factors: decrease in sea level; reduction in spawning areas; the shallowing and silting of migration routes due to the lack of a stable water supply. Measures are proposed to improve the living conditions of aquatic biological resources, aimed at increasing the efficiency of their natural reproduction.

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