Report on the World Aquaculture Society Meeting

The Aquaculture team reflects on their trip to San Diego for an international conference.


The meeting was coordinated by the National Shellfisheries Association.

In March, Aquaculture team members Tim Bean, Hannah Farley, Ophelie Gervais and Yehwa Jin travelled to San Diego for the World Aquaculture Society Meeting, and wrote the following report based on their observations and participation in the event.

“March 2022 saw the reincarnation of the triennial World Aquaculture Society Meeting, including the meeting of the USA National Shellfisheries Association. The meeting was very well attended with around 2,000 registrations (slightly fewer people than usual) and a few changes to the programme right up to the last minute, but it was an extremely successful meeting. Each of the four days saw ten parallel sessions to choose from, including subjects such as mussels, oysters, shellfish genetics and genomics, shellfish disease, vibrio, offshore aquaculture, genetic engineering, and even a session called “down on the farm”.  

“The shellfish disease session was primarily focused on hemocytic neoplasia, or transmissible cancers observed in clam species across the US coastline. These aberrant blood cells are able to move between hosts, where they infiltrate the animal tissues and grow uncontrollably, eventually overcoming the normal functions and resulting in mortality. As they are essentially clam cells, this can be difficult to diagnose with molecular techniques (for example, when using normal PCR, they can’t be differentiated from normal clam tissue), and as such Professor Roxanne Smolowitz’s group have been characterising these cells using histopathology and developing novel diagnostics using RNA based methods.

“The oyster session included a presentation on the successes achieved at two new fully recirculating shellfish hatcheries. Megan Gima reported on the success at the TCMAC Mississippi hatchery. This site has been in operation for four seasons now, after moving to an inland RAS site to overcome water quality issues associated with major weather events. Last year saw the first consistent results, with >90% spawning success and high survival through to spat. The hatchery attributes the increasing success to incremental changes in the recirculation system (including increased filtration) alongside a consistent “bedding-in” of the hatchery; the current artificial seawater (plus top-ups) has been circulated through the system for over 2 years. This technology holds incredible potential in areas of variable water quality and especially in the face of climate change.

Hannah Farley introduces her project on oyster microbiomes.

“In the shellfish genetics and genomics session (of particular interest to the Roslin team), Doctor Konstantin Divilov presented discovery of a novel (QTL) marker of resistance to Californian strains of OsHV-1, which has also been used successfully to select resistant lines via marker assisted selection. It will be really interesting to see if this resistance is transferable to European strains of the virus. Doctor Chris Hollenbeck, of Texas A&M, discussed how a study of oyster population genetics is helping regulators in Texas understand how best to manage the production and movement of oyster spat; this is especially important as conservation of local populations has been deemed critical for approval of aquaculture businesses. In addition, Doctor Hongang Zhao presented an interesting paper on measuring and managing inbreeding in commercial hatchery lines of Crassostrea virginica.

“Microbiome research was well discussed throughout many of the different sessions, covering a range of shellfish species and culture systems. Doctor Luigui Gallardo-Becerra highlighted the importance of microbiome studies and presented an experimental design to investigate the impact of host genotype on the microbiome of Pacific whiteleg shrimp gut and hepatopancreas. Hannah Collins from the University of Connecticut presented her work demonstrating an effect of nylon fibres on the gut microbiome of the blue mussel, Mytilus edulis. Antibiotic resistance was emphasized as a prominent challenge to aquaculture, however, promising research into possible solutions is going ahead. In particular, the hunt for wild caught probiotics was presented by Doctor Jeremiah Minich from the University of California, whereas other researchers and companies presented the use of bacteriophage therapy as an alternative to antibiotics.

“Roslin staff also attended sessions on shrimp health and disease as well as genetic engineering. In the shrimp session, they learned about CRISPR-based diagnostics for disease detection in shrimp from Shelly A. Trigg et al (Gloucester Marine Genomics Institute) and oral delivery of gene-therapy (such as RNAi) in shrimp using one of shrimp viruses as a viral vector by Rod Russel R. Alenton et al (University of Arizona), as well as how the genomic reconstruction of the WSSV and TSV pathogens from archived shrimp histology blocks has expedited pathogen discovery, as reported by Arun K. Dhar et al (University of Arizona). Meanwhile, during the genetic engineering session (chaired by Yonathan Zohar and John Buchanan), Alan Tinch from the Center for Aquaculture Technologies (CAT) discussed the benefits genome editing can bring in aquaculture. Alan's presentation was followed by talks on the optimisation of genome editing tools, novel sterilisation approach, and the delivery tools for gene silencing and editing in various aquaculture species.

“A pursuant fish health session was mostly focused on the development of vaccines. Doctor Esteban Soto demonstrated that vaccination using injection was more effective than immersion vaccine, even if it is more stressful for the fish. In another presentation, Evan Jones conversely demonstrated the limitation of vaccine injection in the industry, as it is too time consuming and can’t be done on small fish where they are the most vulnerable. To overcome these problems developers are now working on promising oral vaccines, the same size as fish food.

“Four Roslin staff and students were lucky to attend and present at the meeting, with Yehwa Jin presenting her work on gene editing in Salmon, Ophelie Gervais presenting recent studies on ISAV, Tim Bean discussing work on the bivalve evolution, and Hannah Farley introducing her project on oyster microbiomes. It was rewarding to participate in this year’s World Aquaculture Society Meeting and we hope to be in attendance at the next National Shellfisheries Association meeting, which will be held in March 2023 in Baltimore, Maryland.”

Tim Bean discusses bivalve evolution with other attendees.