This paper is a retrospective review of Carp Polyculture in Nepal. Polyculture is an art and science of growing two or more compatible fish species in a pond to maximize production by taking advantage of different spatial distribution and feeding habits. Polyculture concepts rely on the complete utilization of various spatial niches and trophic of a pond to acquire a maximum production per unit area. Carp polyculture is the most common, popular, and successful aquaculture system in Nepal. Carp polyculture is the major aquaculture system contributing to more than 90% of total aquaculture production in Nepal. In 2018/19, total fish production, aquaculture, and productivity were 91,832 t, 70,832 t, and 4.92 t/ha, respectively, which is insufficient to fulfill the growing demand for fish in Nepal. Therefore, it is essential to increase production and productivity.
Table of Contents
1. Carp polyculture
2. Principle of carp polyculture
3. Principal requirements of different species in combination
4. Pros and cons of carp polyculture
4.1 Pros of polyculture
4.2 Cons of polyculture
5. Stocking
6. Water quality requirements for carps and Nile tilapia
7. Feed and feeding
7.1 Natural food
7.2 Supplementary food
8. Liming
9. Fertilization
Research Objectives and Core Themes
This review aims to analyze the practice of carp polyculture as a primary aquaculture method in Nepal, evaluating its efficiency, management principles, and potential to enhance national fish productivity to meet rising food demand.
- Ecological principles and synergistic species combinations in polyculture.
- Optimizing water quality and environmental conditions for carp production.
- Strategic management of natural and supplementary feeding techniques.
- Technical requirements, including liming and fertilization practices, for maximizing pond output.
- Assessment of the economic viability and food security benefits for rural farmers.
Excerpt from the Book
Principle of carp polyculture
The motivating principle is that a combination of different species can maximize fish production. Different species combinations in a polyculture system effectively utilize available natural food produced in a pond and contribute to improving the pond environment. Polyculture management is based on the relationship between organisms at different levels of the food chain (Singh, Maqsood, Samoon, Verma, Singh, & Saxena, 2020). Therefore, the selection of species plays a vital role in the polyculture system because all of the species should benefit from the available food without competing with one another (Yin, Zhu, Zhou, Li, Wang, & Liao, 2017). In this system, food niches are enriched by using fertilization or supplemental feeding, but only with a proper combination and densities will utilize it efficiently. A suitable combination of species will maximize the synergistic and minimizes antagonistic fish-fish and fish-environment relationships.
Synergistic interaction is based on two processes: improved environmental conditions and an increase in food resources. The mechanisms through which different fish species contribute to the improvement of environmental conditions depend on the specific levels of the food chain at which they feed (Milstein, 1992). An example of increased availability of food resources is illustrated by the Chinese proverb `feed one grass carp well, and you feed three other fish (Opuszynski, 1986). At the macrophytic level, grass carp ingest many plant materials and decrease excess plant growth, which prevents nocturnal oxygen deletion. Moreover, its feces are the source for detritivorous fish and have a fertilization effect on phytoplankton, which is grazed by silver carp at the planktonic level. Besides, feces of silver carp which have partially digest phytoplankton are being eaten by common carp, which otherwise would not have been utilized. At the benthos level, common carp stir the mud, which would recirculate nutrients helps the development of phytoplankton, thus food for silver carp. As grazing on algae, it will control bloom and avoid the risk of O2 depletion, thus improving the heterotrophic food chain, improving bottom-feeding fish. At the heterotrophic level, detritivorous fish helps in the improvement of water quality.
Summary of Chapters
Carp polyculture: Defines the polyculture system as a method to grow multiple compatible fish species together, highlighting its characteristics like low investment and high profit potential.
Principle of carp polyculture: Explains how species combinations maximize production by effectively utilizing different food niches and establishing synergistic relationships within the pond ecosystem.
Principal requirements of different species in combination: Outlines the four fundamental criteria for selecting fish species, including feeding habits, niche occupancy, and non-predatory behavior.
Pros and cons of carp polyculture: Discusses the advantages, such as efficient resource use, and challenges, such as the need for technical expertise and fingerling procurement.
Stocking: Examines the factors influencing stocking rates and ratios, emphasizing the importance of balancing biological productivity with market demand.
Water quality requirements for carps and Nile tilapia: Provides an overview of essential physical and chemical water parameters necessary for optimal fish health and productivity.
Feed and feeding: Details the importance of natural versus supplementary feeding strategies, including the calculation of Feed Conversion Ratios (FCR).
Liming: Discusses the role of liming as a technique to treat acidic soils and increase water alkalinity to improve fertilization response.
Fertilization: Explains how organic and inorganic fertilizers are used to stimulate primary productivity and increase the abundance of natural fish food.
Keywords
Carp, Polyculture, Aquaculture, Productivity, Fish farming, Water quality, Stocking density, Feed management, Fertilization, Liming, Ecological niches, Food chain, Sustainability, Nepal, Synergistic interaction
Frequently Asked Questions
What is the core focus of this research?
The research provides a comprehensive review of carp polyculture, identifying it as the most prevalent and successful aquaculture practice in Nepal and exploring techniques to optimize its yield.
What are the primary thematic areas covered in this work?
The work covers species selection, ecological principles of polyculture, pond water management, feeding strategies, and the application of fertilizers and lime to enhance production.
What is the primary goal of the study?
The primary goal is to provide a knowledge base on carp polyculture management that can help farmers increase productivity to meet the growing national demand for animal protein.
Which scientific methods are analyzed for production?
The text analyzes various management techniques, including stocking density optimization, multi-trophic species integration, water quality monitoring, and supplemental feeding regimens.
What topics are explored in the main body of the text?
The main body treats the biological principles of synergy between fish species, practical requirements for stocking, detailed water quality parameters, and the technical aspects of pond preparation.
Which keywords characterize this research?
Key terms include carp polyculture, aquaculture, productivity, ecological niches, feed management, and water quality.
How does the system utilize different ecological niches?
The system utilizes different levels of the food chain by combining species that feed on plankton, macrophytes, detritus, and bottom sediments, preventing competition and maximizing food utilization.
Why is liming considered a vital step in pond management?
Liming is essential for ponds with soft water or acidic soil to raise alkalinity, which helps stabilize the environment and significantly improves the effectiveness of subsequent fertilization.
What role does the Feed Conversion Ratio (FCR) play in this production model?
FCR is used as a critical metric to evaluate the efficiency of supplementary feeding; a lower FCR is preferred as it indicates that fish are successfully converting inputs into growth.
- Arbeit zitieren
- Saurav Lamichhane (Autor:in), Biplov Shrestha (Autor:in), Parbati Kandel (Autor:in), 2021, A Retrospective Review of Carp Polyculture in Nepal, München, GRIN Verlag, https://www.grin.com/document/1014217
