EXPOSURE METHODOLOGIES AND SYSTEMS FOR LONG-TERM CHEMICAL CARCINOGENICITY STUDIES WITH SMALL FISH SPECIES

1999 ◽  
Vol 9 (3) ◽  
pp. 201-217 ◽  
Author(s):  
Charles Manning ◽  
Alexander Schesny ◽  
William Hawkins ◽  
David Barnes ◽  
Carolyn Barnes ◽  
...  
Keyword(s):  
Fish Species ◽  
Small Fish ◽  
Chemical Carcinogenicity

Trophic position and individual feeding histories of fish from Lake Okeechobee, Florida

1999 ◽  
Vol 56 (4) ◽  
pp. 590-600 ◽  
Author(s):  
Brian Fry ◽  
Patricia L Mumford ◽  
Franklin Tam ◽  
Don D Fox ◽  
Gary L Warren ◽  
...  
Keyword(s):  
Fish Species ◽  
Trophic Position ◽  
Trophic Levels ◽  
Small Fish ◽  
Lake Okeechobee ◽  
Isotopic Analyses ◽  
Marsh Site ◽  
C And N ◽  
Almost All

We used C and N stable isotope measurements to identify trophic position and feeding histories of fish from Lake Okeechobee, one of the largest lakes in North America. When δ15N values were used to estimate trophic levels, analyses of about 500 individual fish collected in two seasons at five sites showed that trophic level varied from 2 (herbivore) to 4.3 (second-level carnivore) among the 29 fish species examined. Lower trophic levels predominated among small fish caught at a littoral marsh site, and highest trophic levels were found among larger offshore fish. Marsh fish showed about three times the C isotope variation than did offshore fish, consistent with the wider array of foods in the marsh versus offshore food web. In addition to these community-level results, there were often unexpected large isotopic differences between individuals in almost all fish species examined, suggesting large differences in individual feeding behavior. Isotopic analyses indicate long-term differences in feeding among individuals, in addition to the short-term differences often observed in stomach content studies. Long-term individual variation in fish foraging may be important in understanding variation in other biochemical parameters measured in fish, such as Hg or PCB contents.

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.

Mindtree: Tryst with the Corporate Control Market

2021 ◽  
pp. 227797792199190
Author(s):  
P. Bala Bhaskaran
Keyword(s):  
Capital Market ◽  
Corporate Control ◽  
Theory And Practice ◽  
Effective Control ◽  
Small Fish ◽  
Market Theory ◽  
Strategic Fit ◽  
Sequence Of Events ◽  
The Capital Market

The case is structured around the takeover of Mindtree Ltd (ML) by Larsen & Toubro Ltd (L&T) in June 2019. ML was founded and nurtured by a group of software professionals. In two decades, it had blossomed into an enterprise with global presence, US$ 1 billion turnover and a unique organizational culture. In a strange sequence of events, more than 20% of ML’s shares landed in L&T’s lap. L&T grabbed this opportunity and ran a systematic campaign to acquire the company. In about 100 days, L&T achieved its objective and got into the driver’s seat. The case traces the evolution of ML from a start-up to a publicly held company with global standing. It examines the circumstances and events leading to L&T getting the initial stake in the company; it examines the acquisition campaign of L&T and the response of the top management of ML. Research Questions Was there a strategic fit between ML and L&T? Were the capital market processes just and fair to all the stakeholders involved in the acquisition? Was L&T fair, prudent and sensitive in the acquisition process? Was Siddhartha loyal and fair to the founders of ML? Link to Theory The theoretical concepts that would enable a better comprehension of the case are: Analysis of strategic fit in M&A situations Capital market: Theory and practice Strategy for corporate control of an enterprise Significance of culture and ecosystem in knowledge organizations Phenomenon Studied Leadership styles relevant at different stages of evolution of an enterprise are different. A leader, at a given point of time, is successful when he is able to match his aspirations with the leadership needs of the enterprise at that point of time. The case can be used to demonstrate this phenomenon. Case Context Context of the case is that of an emerging infotech enterprise, coming under corporate raid and the unfolding capital market processes. The case highlights the shortcomings of the co-founders, leading to their unseating as also the sensitivity of the incoming management in handling the transition. Findings The case demonstrates the ability of the capital market to be fair to all stakeholders ensuring reward for competence and punishment for sloppiness. The case emphasizes the need for co-founders to have an effective strategy for corporate control; only then they could hope to achieve the long-term objectives. The case also illustrates the significance of sensitivity in handling softer issues like people and ecosystem in ensuring long-term success. Discussions At the outset, the case may appear to be that of a big fish swallowing a small fish. But a closer scrutiny would reveal the multiple dimensions of the case. Consider the role of Siddhartha. He seeded the idea of the company; he was a financier to it; he remained an investor in the company longer than most of the founders; when he pulled out, the co-founders could not hold the company together. Neither Siddhartha nor the co-founders had the far-sightedness to consolidate their shareholdings for effective control of the company into the future. This would trigger discussions on the differing roles of technocrats, managers, leaders and founders. Another point worthy of discussion would be: How were the co-founders choosing their leaders? Was it by rotation among themselves, or did they engage a set of criteria to identify an incumbent capable of leading a global company?

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.

The issue of assessment of efficiency of works on land reclamation fisheries in inland waters of Russia

2021 ◽  
pp. 8-20
Author(s):  
Andrey Dmitrievich Bykov ◽  
Svetlana Yuryevna Brazhnik
Keyword(s):  
Fish Species ◽  
Land Reclamation ◽  
Long Term Results ◽  
Predatory Fish ◽  
Federal State ◽  
Inland Waters ◽  
Ecological Group ◽  
Spawning Grounds ◽  
Commercial Fish

The article considers the issue of assessing the long-term results of work on fisheries reclamation in inland waters of fisheries significance in Russia, carried out by the branches of the Federal State Budgetary Institution “Glavrybvod” on the state task in terms of their effectiveness. The relationship between dredging and clearing of watercourse beds and the dynamics of the number of producers of semi-navigable and non-aquatic fish in these rivers during spawning migrations has not been established. With long-term mowing of wetland vegetation in the shallow waters of reservoirs, deltas of large rivers and estuaries, there is no increase in their commercial fish productivity. A number of examples show the opposite effect of this type of work, which leads to a local deterioration of the ecological state of these reservoirs. At the same time, the repeatedly proven method of combating higher aquatic vegetation in the reservoirs of the south of Russia in low water conditions as biomelioration, based on the introduction of fish, consumers of autotrophic products by regional branches of the Federal State Budgetary Institution “Glavrybvod” is practically not used. When installing artificial spawning grounds in the littoral zone of reservoirs, regular ichthyological monitoring of the effectiveness of spawning on them is not carried out. There are no reliable data confirming the significant positive impact of artificial spawning grounds on the population dynamics of commercial fish species of the limnophilic ecological group under conditions of significant spring water level depletion in Russian reservoirs. When catching predatory and low-value fish species in water bodies, legal obstacles arise due to the fact that the volume of seizure of predatory fish includes commercial objects for which the ODE is established annually and their catch is already carried out according to industrial quotas.

Change in the rocky reef fish fauna of the iconic Poor Knights Islands Marine Reserve in north-eastern New Zealand over 4 decades

2018 ◽  
Vol 69 (10) ◽  
pp. 1496
Author(s):  
David R. Schiel ◽  
Tony Ayling ◽  
Michael J. Kingsford ◽  
Christopher N. Battershill ◽  
J. Howard Choat ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Species ◽  
Marine Reserve ◽  
Fish Fauna ◽  
Rocky Reef ◽  
Long Term Effects ◽  
Before And After ◽  
Negative Effect ◽  
Reef Fish Species

Marine reserves exhibit increases in targeted fish species, but long-term effects on biodiversity are poorly understood. Factors other than reserve status may affect decadal changes, including environmental change. We examined the fish fauna at the iconic Poor Knights Islands over 4 decades (1974–2016) before and after implementation of a no-take marine reserve in 1998. We document a substantial increase in commercially and recreationally targeted Chrysophrys auratus, which was virtually absent before 1994 but by 2016 had reached up to 11 fish per 500m2 (220 per hectare). There were also large changes to the fish community, including the decline of subtropical and coastal wrasses, some species with no change and others that increased significantly. Many declines occurred >20 years before the arrival of abundant C. auratus, suggesting the changes do not represent a trophic cascade. Furthermore, this normally benthic-feeding fish has adopted a mid-water foraging behaviour targeting planktivorous fish. The increase in C. auratus appears to be linked both to reserve status and catch regulations in the wider region. Overall, the data point to long-term environmental fluctuations from the late 1970s having a negative effect on the abundance of more than half the reef fish species at these islands.

Small Fish, Big Questions: Inquiry Kits for Teaching Evolution

2018 ◽  
Vol 80 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Emily A. Kane ◽  
E. Dale Broder ◽  
Andrew C. Warnock ◽  
Courtney M. Butler ◽  
A. Lynne Judish ◽  
...  
Keyword(s):  
Natural Selection ◽  
Evolution Education ◽  
Small Fish ◽  
Teaching Evolution ◽  
Local Schools ◽  
Broader Impacts ◽  
Hands On ◽  
Education And Outreach ◽  
Evolution By Natural Selection

Evolution education poses unique challenges because students can have preconceptions that bias their learning. Hands-on, inquiry approaches can help overcome preset beliefs held by students, but few such programs exist and teachers typically lack access to these resources. Experiential learning in the form of self-guided kits can allow evolution education programs to maximize their reach while still maintaining a high-quality resource. We created an inquiry-based kit that uses live Trinidadian guppies to teach evolution by natural selection using the VIST (Variation, Inheritance, Selection, Time) framework. Our collaborative team included evolutionary biologists and education specialists, and we were able to combine expertise in evolution research and inquiry-based kit design in the development of this program. By constructing the kits with grant funds slated for broader impacts and maintaining them at our university's Education and Outreach Center, we made these kits freely available to local schools over the long term. Students and teachers have praised how clearly the kits teach evolution by natural selection, and we are excited to share this resource with readers of The American Biology Teacher.

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.

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