Warm Water Marine Fish (Seabass, Sea bream, Barramundi, Yellowtail)

What’s important for warm water marine fish?  

• High water quality 
• Correct water temperature 
• Sufficient tidal movement (if cage farming) 
• Optimal pH levels (If operating a recirculating system)
• Sourcing strong fingerlings
• Stable environmental conditions  
• Optimal oxygen conditions

Common challenges 

For seabass: 

• Slow growth: This is often due to being raised in small ponds.  
• Spread of pathogens: Viruses, bacteria and parasites are often spread via other fish, which are being used to help cut costs. 
• Anemia: This can be caused by leeches and contributes to lethargy and poor performance. 
• Streptococcus bacteria: A viral infection that can affect major organs such as liver, pancreas and heart if not treated and managed correctly.

 For sea bream: 

• Edwardsiella tarda: Local strains of this bacteria do not cause high peaks of mortality but can slowly kill fish during the cycle. A common cause is stress. Affected fish do not always die, but they cannot be harvested due to apparent injuries to the skin, eyes and head, or a noticeably “off” smell.  
• Henneguya pagri: A myxospora that affects internal organs and oxygen absorption of younger fish. 

For barramundi:

• Iridovirus: This is the most severe disease for barramundi, causing mortality of up to 80–90%.
• Parasites: Neobenedinia commonly affects newly stocked barramundi in open ocean cages — fish may develop skin and tail rot and mortality rates can go as high as 30–40%.
• Streptococcus iniae: This is the most serious bacterial disease to Barramundi, causing acute mortality with a cumulative mortality of up to 70%.

For yellowtail: 

• Lactococcus type 2: Spikes of mortality may occur, especially during the summer months.  
• Fishmeal replacement: Yellowtail are highly carnivorous and have higher protein requirements than salmonids. 
• Benedenia seriolae and Neobenedenia girellae (skin flukes): These parasites appear year-round but are especially prevalent during the summer months. 

Tips for maximizing health and performance 

• Optimize feed and water quality 
• Reduce stocking density (to prevent cannibalism and stress) 
• Minimize stress during transportation 
• Improve gut health 
• Formulate stress-resistant nutrients in feed to help enhance immunity 
• Provide proper ventilation, such as in the case of air-breathing catfish species  
• Apply correct feeding levels (just below satiation)