From boom to uncertainty in largemouth bass aquaculture in China

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Post pandemic, industry is optimistic on the potential growth of this fish

By Zhang Yufan and Henry Wong

A largemouth bass grow-out pond in Foshan, Guangdong.

China, often referred to as the global aquaculturepowerhouse, boasts the farming of the most extensivearray of aquatic species. Its aquaculture industry issynonymous with the culture of the “four major carp” fish,collectively known as Asian carps, which account for abouthalf of China’s aquaculture production in terms of volume.

A Rising Star

The largemouth bass, affectionately referred to as the‘California bass’ in China, has made a remarkable leap in production, emerging as the next major freshwater cultured fish after the Asian carps. The largemouth bass consumption market primarily thrives in tier one and two cities, harbouring considerable potential for market expansion.

The growth of large mouth seabass in China

The largemouth bass (Micropterus salmoides), originally from North America, was introduced to mainland China in1983. Over the past 30 years, the industry has fine-tuned its operations, creating a complete supply chain from seed production to marketing.

A storage room for largemouth bass feed

Data from the Chinese Fishery Yearbook showed its production increasing from 457,000 tonnes in 2017 to 802,000 tonnes in 2022. The main aquaculture regions are in Guangdong, Zhejiang, Jiangsu, Hunan and Sichuan provinces. In 2022, the total aquaculture production in these top five provinces was approximately 685,000 tonnes, accounting for 85% of the national total, with Guangdong alone contributing about 382,000 tonnes or48% of the national total.

Largemouth bass feeding on the water surface.

Pond culture in Guangdong

Pond culture is the most prevalent, particularly inGuangdong province. The sizes of ponds typically range from 2,000 to 3,500m2with water depths of 1.5 to 2.0m.Stocking densities in ponds are approximately 4,000to 10,000 juveniles (8-10cm) per 1,000m2. In the past, largemouth bass in China were primarily fed frozen trash fish during their growth phase, yielding a feed conversion ratio (FCR) exceeding 4.0 but its farming was still profitable.

Since 2017, the government has discouraged feeding of frozen trash fish in aquaculture, leading to the development of commercial pelleted feeds. FCR improved to 1.1-1.3.Commonly, largemouth bass extruded feeds have 44-48% crude protein. The use of such feeds in farming requiresless labour, improves water quality and reduces risks of diseases.

Price seasonality and profitability

Price fluctuations over the past five years reveal significant seasonality in the market for largemouth bass. Prices remain steady from January to April each year and steadily rising from May to August to reach their annual peak. In October, prices undergo a decline due to an increase of supply at year-end. The decline continues into the beginning of the following year.

The recorded best profit occurred in August 2019, reaching an impressive RMB14.8/500g (USD4.06/kg). In 2022, increases in production costs related to feed ingredients, pond rentals and labour resulted in a production cost increase of RMB1-1.50/500g (USD0.27-0.41/kg) compared to the previous year. In Guangdong, rearing the first crop incurred a cost of approximately RMB9-11.5/500g (USD2.46-3.14/kg). However, the farm gate price showed a nearly RMB1/500g (USD 0.27/kg) year-on-year decrease, reducing the average profitability of largemouth bass farming in 2022 by an estimated RMB1-2/500g (USD0.27-0.54/kg).

In 2023, the largemouth bass industry encountered an unexpected price collapse and caught many farmers off guard. The average price of largemouth bass in major producing areas was approximately RMB12.8/500g(USD3.51/kg), with some areas, such as in Foshan (Guangdong Province), seeing historic lows of RMB11/500g or USD3.0/kg (October, www.fishfirst.cn). High pond rental costs, expensive feed and low fish prices prompted many farmers to reconsider restocking and farming.

A farmer manually broadcasting feed to largemouth bass.

To gain insight into the situation, the authors visited Mr Chen, a pioneer of largemouth bass farming in China. He attributed the price decline to an oversaturated market, noting that the industry had grown significantly over the years, 2017 to 2019. This expansion, combined with the industry’s reliance on credit sales and private lending, placed immense pressure on the entire supply chain, affecting farmers, feed distributors and raw material suppliers. As a result, some farmers hesitated to sell their fish due to poor prices, and the ongoing decline in fish prices since August exacerbated financial difficulties of farmers across the industry.

Challenges

The industry has long grappled with disease-related challenges, which have intensified this year due to increases in stocking density. During the larval stage, splenorenal necrosis virus outbreaks often result in the mortality of over50% of larvae. Iridoviridae viruses are also prevalent and their uncontrolled presence in the middle and late stages offish farming can lead to mortality rates of around 15-20%.

Feed, constituting 70% of farming costs, accounted for both cost and nutritional issues. In 2018, a tonne of large mouth bass feed cost around RMB11,000 /tonne(USD1503), with a feed conversion ratio (FCR) of close to1.05. Presently, feed prices have surged to RMB13,000/tonne (USD1785.50) while the FCR has exceeded 1.2. Additionally, nutritional problems were intertwined with diseases, leading to the rising occurrences of pale liver and pericardial congestion. These multi challenges pose diagnostic and treatment complexities. Furthermore, there have been reports on the yellow flesh of largemouth bass, rendering them unmarketable.

Largemouth bass extruded feed.

New developments in nutrition

Initially, the nutrition of largemouth bass was primarily focussed on macro nutrients, particularly protein, amino acids, lipids and carbohydrate digestibility, aiming to replace frozen trash fish in their diet. However, recent scientific advancements have shifted the focus towards micronutrient studies, specifically vitamins and minerals.

The Guangdong Academy of Agricultural Sciences in China made a significant discovery, revealing that incorporating selenium yeast (Alltech Sel-plex) in the feed substantially enhanced the antioxidant capacity of largemouth bass haemocytes and reduced apoptotic cell counts. This form of selenium also proved more efficient in accumulating selenium in fish muscle compared to inorganic selenium (Xu et al., 2023). Another study by Sun Yat-sen University showed that substituting inorganic zinc with zinc proteinate in largemouth bass feed improved their growth performance. The optimal dosage of peptide zinc, at just60ppm, was significantly lower than the industry’s usage of inorganic zinc. This low-dosage, high-efficiency zinc source enhanced largemouth bass’ overall antioxidant capacity and muscle quality (He et al., 2023).

Conclusion

Although the farming of largemouth bass still faces many challenges, it is important to remember that this is just apart of its farming development. With the right approach and continued dedication, the industry is poised to rebound. Market factors, including the lower demand caused by the post-pandemic recovery and increased feed costs, have undoubtedly changed the supply and demand curve.

Optimism is warranted for the potential future growth of this species. With advancements in genetics, precision nutrition and a growing market acceptance for largemouth bass, the culture of this species will take a turn for the better. It is a testament to the resilience and adaptability of aquaculture, and it reinforces the industry’s ability to overcome challenges and thrive in the face of adversity.

Authors:  

Dr Henry Wong is Commercial Development Director, Asia Aquaculture, Alltech. 
Dr Yufan Zhang is China Aqua Business Development Manager Alltech China.

This article was published in the print edition of Aqua Culture Asia Pacific in November/December 2023.

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