Saving Seafood

A test to diagnose psychopaths can help identify fish behaviours that could benefit aquaculture

October 19, 2021 — Personality profiling is not unique to criminology. The method is used to identify health risks, aid personnel recruitment, develop education programs and build dating apps. Despite this wide range of applications, there is one thing all these approaches have in common: they are almost exclusively used on humans.

Biologists recognize that animals have personality traits that are consistent across time. However, animal behaviour is often studied in large groups of animals so that data can be collected to investigate wide-scale trends. This means the need to build detailed personality profiles on an individual scale is uncommon.

Unless, as demonstrated by the case of Jack the Ripper, there are unknown individuals within a population that exhibit a rare behaviour and are avoiding detection.

Cleaner fish remove and eat parasites from the skin of other fishes. Some species of cleaner fish are used in salmon aquaculture to help control parasitic sea lice. Lumpfish are a commonly used cleaner fish, and millions of juveniles are released into salmon farms each year. However, only a minority of lumpfish (around 20 per cent) actually clean salmon of sea lice, while the rest either ignore salmon or compete for pellet food.

It is unclear why only certain lumpfish clean salmon and observing this behaviour is exceedingly rare. As part of a research team at the Centre for Sustainable Aquatic Research at Swansea University, my colleagues and I tried to solve this mystery by following the same logic as the Hare Psychopathy Checklist.

We designed a series of behavioural tests to build detailed personality profiles of lumpfish, in hope of identifying the individuals that showed cleaning behaviour. This involved testing for variation in activity, aggression, anxiety, boldness and sociality of individual lumpfish over repeated sessions, and then recording how these individuals interacted with salmon.

Read the full story at The Conversation

 

New tool to improve ‘cleaner fish’ welfare in salmon farming

July 30, 2021 — Researchers at the University of Stirling have developed a new tool that fish farmers can use to improve the welfare of lumpfish—a species crucial to tackling the problem of sea lice in salmon.

Lumpfish are increasingly being used by the  industry as a ‘cleaner fish’ to remove parasitic sea lice, which cost the Scottish salmon industry alone an estimated £40m per year.

Because they are a relatively new fish to aquaculture, researchers are still establishing the optimum conditions for lumpfish .

In a new study, a team led by Dr. Sonia Rey Planellas at the University of Stirling’s Institute of Aquaculture has established the correlation between lumpfish growth weights and welfare, and turned it into a tool farmers can use to assess the health of the fish and take remedial action if required.

Dr. Rey Planellas says that “at the moment, in the UK we use Operational Welfare Indicators (OWIs) for fish welfare, but lumpfish are a different shape to many other fish, so it’s about identifying the best indicators for each species.”

“Fin damage is typically the indicator that is used, but in this study we found a more useful indicator was the correlation between growth weight relative to size and welfare.”

Read the full story at PHYS.org

High hopes to diversify US marine finfish aquaculture

March 13, 2019 — Spotted sea trout, wolffish, tripletail, California halibut, southern flounder, lumpfish and greater amberjack are amongst the prime candidate species that might allow for the US to diversify its marine finfish aquaculture sector.

So argued members of a distinguished panel of researchers during a special session of Aquaculture 2019 in New Orleans on 10 March – a session that offered some hope that diversification could help the country expand its marine finfish production and to reduce its $15 billion seafood deficit.

Eric Saillant from the University of Southern Mississippi’s Marine Aquaculture Centre, outlined the potential and pitfalls facing tripletail production, noting that “current data suggest that tripletail could become a successful species for commercial marine aquaculture, assuming that bottlenecks in the hatchery [phase] can be overcome.”

Read the full story at The Fish Site