Fisheries, Aquaculture, & Sustainable Seafood

Chile’s salmon aquaculture benefits from fallowing – and so too could trout farmers

In Chilean salmonid farmers’ worst nightmares, Piscirickettsia salmonis must be a regular feature. This bacterium causes Salmon Rickettsial Septicaemia (SRS), a highly infectious disease whose symptoms include haemorrhaging, lesions, ulcers, anorexia, and many cases death.

SRS is an epidemic in Chile, costing the salmon aquaculture industry over US $300 million each year. Vaccines have been largely ineffective and antibiotics have given mixed results. Mandatory three-month fallowing, on the other hand, seems to routinely reduce the chance of reinfection.

The underlying principle behind fallowing is fairly straightforward. Net-pen systems commonly used by finfish farmers allow pathogens to spread into the wider environment. Some are carried away by currents, some remain suspended in the water column or on the seafloor under and near the farm. In all cases, they wait for a new host to come close enough for reinfection. Fortunately for the fish, and the farmer, pathogens can’t survive forever without a host – which is where fallowing comes in. Take the hosts away and all the equipment out of the water for disinfection, and the odds of contagion rapidly drop…


This article was written for The Fish Site – please continue reading here.

Climate Change, Acidification, & the Oceans

Pacific Islanders to face climate change challenges

Ahh the Pacific Islands…white sand, warm water, sun shining down….it sounds wonderful (especially for me – I’m having a ‘year of winter’ with my moving about).

But things are changing, and perhaps nothing is quite changing on a global scale quite like the climate.  If your a Pacific Islander, climate change is likely to be a huge problem.  It all comes down to reliance on local resources, and in many cases these resources come from local marine waters.  From a food perspective, Dr Johann Bell of the Secretariat of the Pacific Community and colleagues from around the globe predict things are going to change a fair bit….here’s some highlights from the paper: Continue reading “Pacific Islanders to face climate change challenges”

Fisheries, Aquaculture, & Sustainable Seafood

Move over beef production – aquaculture in the new kid on the block

Farmed fish and shellfish is becoming increasingly common in our supermarkets, but did you know that global aquaculture production has now overtaken beef production?

In this short article, Professor Kenny Black of the Scottish Association for Marine Science gives us an overview of the environmental impacts of this huge industry.  It’s not all doom and gloom though.  For example, he explores the role of genetically modified seeds to provide an alternative food-source for many aquaculture species that currently rely on dwindling wild-fish populations.

Ultimately, Black says, we will need aquaculture to feed our growing human population.  It has a lower carbon footprint than some of our intensively farmed beef, but the problem of feeding carnivorous fish like salmon from wild-caught fish may remain a substantial issue.  The solution?  Lets start eating sea cucumbers.

Image: Fish for sale at Gold City Supermarket.  Credit Wally Gobetz/Flickr (CC BY-NC-ND 2.0)