Health & Welfare

A significant part of any hematological evaluation of fish is the preparation, microscopic examination and interpretation of stained blood smears. 

Shrimp do not produce antibodies and therefore do not remember prior exposure to pathogens, a critical component of long-term protective immunity. 

A pilot project in Kentucky that uses wastewater effluent and decommissioned tanks at a water treatment plant has cultured over 70,000 phase II paddlefish. 

Tilapia infected with streptococcosis pathogens exhibit similar clinical signs, including lethargy, abnormal swimming and lack of appetite. 

The advent of specific pathogen free Pacific white shrimp became a powerful tool for lessening the impacts of diseases in aquaculture. 

Although selection in fish is progressing rapidly, slower adaption to captivity over several generations can limit animal welfare problems. 

Hubbs-SeaWorld Research Institute developed an integrated larval-nursery recirculating aquaculture system for California halibut utilizing shallow raceways for juvenile culture. 

While Asia’s more extensive approaches for cobia larviculture are effective, more intensive methods are used in the Americas. Most facilities still rely heavily upon wild-capture broodstock. 

In Brazil, shrimp hybrids – crosses of imported specific pathogen-free lines and a genetically improved and locally adapted line – outperform their parents. 

Once satisfactory performance is demonstrated in commercial larval rearing and grow-out, automated induction will finalize the triploidy commercialization. 

To alleviate problems associated with conducting research on fish of unknown and likely diverse genetic backgrounds, a collaborative project has been established to produce a stock of rainbow trout with a defined genetic background for use in fish nutrition research. 

In hatchery feeding trials, winter flounder juveniles reared on white worms grew the most, while pellet-reared fish had the lowest growth and survival. 

USDA and partners are developing channel catfish that exhibit superior growth, fillet yield and resistance to enteric septicemia. Although ongoing research continues to select the USDA lines for better performance, studies comparing the strains have been inconclusive. 

New Zealand’s National Institute of Water & Atmospheric Research has established broodstock research for several emerging species to provide genetically diverse, domesticated stocks for aquaculture industry expansion. 

In general, benefits from genetic increases in growth rate result from better farm environments. Breeding programs should focus selection on genes expressed favorably in the environment that most affect farm profit.