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.

Conservation & Sustainable Management, Fisheries, Aquaculture, & Sustainable Seafood

How special is a ‘Special Area of Conservation?

 

This week it has been brought to my attention that there is a proposal to dredge for scallops inside a ‘Special Area of Conservation’ located in Cardigan Bay, Wales.  This proposal has divided opinions.  On Twitter this week Professor Callum Roberts, a marine conservation biologist at the University of York (UK) lamented that there was ”No hope for UK marine conservation if this mad proposal to scallop dredge in a protected area goes ahead” .  Dr Magnus Johnson, a Crustacean Fisheries and Ecologist researcher at the University of Hull (UK) quickly countered “It is worth reading the science by first!”, following with a couple of hashtags “#eatmorefish #eatmoreshellfish”.  Two scientists, with two opposing views… what is going on?

 

What is a Special Area of Conservation anyway?

These are something unique to the European Union.  They arise from the Habitats Directive, first adopted in 1992 in response to a European convention called the Berne Convention.  Special Areas of Conservation (SAC) are designed to protect a number of habitats and species (plants and animals) considered endangered, vulnerable, rare, or endemic.  Once a SAC has been formally designated, the establishment and implementation of management measures are largely left down to the individual Member State.  However, there are certain things that they must do.  Briefly, under Article 6 of the Habitats Directive, these include:

Continue reading “How special is a ‘Special Area of Conservation?”

Conservation & Sustainable Management, Fisheries, Aquaculture, & Sustainable Seafood, Science Communication

Oh Canada – what about your ocean?

This is a big post.  It’s about big things.  Important things too.  It deals with Canada – a big country.  Actually by area, it is the second largest country in the world.  It also has a lot of ocean under its jurisdiction.  Take a look at the website of Fisheries and Oceans Canada, a Federal government body, and you will see statements like this:

“The Government of Canada is working to ensure the future health of Canada’s oceans and ocean resources by increasing understanding and protection of our oceans; supporting sustainable economic opportunities; and demonstrating international leadership in oceans management”

Sounds good doesn’t it.  The Canadian Federal Government (which has just changed as of yesterday – see bottom of the post) have a several Acts in place to govern the bit of the ocean they have claimed as theirs.  Great stuff!  Except maybe, as demonstrated in a recently published paper, authored by 19 Canadian scientists including lead-author Megan Bailey (Dalhousie University), “over the past decade decision-making at the federal level appears to have undermined the government’s own mandates for the sustainable management of Canada’s oceansContinue reading “Oh Canada – what about your ocean?”

Fisheries, Aquaculture, & Sustainable Seafood

How deep is too deep for commercial fishing?

Our ever-improving technology has allowed us to fish longer, catch more, and move further from land.  It has also allowed us to fish deeper.  EU statistics indicate that between 1950 and 2006 fishing depths increased from an average depth of 407 metres, to 535 metres.

Life in the deep is slow-paced.  Food is scarcer than in the sunlit surface waters.  Species grow slower and live longer.  Some deep-sea corals, like the one in the image, are thought to be over 4,000 years old. Traits like these are why organisations like Marine Conservation Institute that ” The deep-sea is the world’s worst place to catch fish” .  It’s not just the sustainability of targeted species that is causing concern, but of those caught as bycatch, as well as damage to the seabed and the flora and fauna living in and on it – like the coral in the photo.  So can deep-sea fishing ever be managed sustainably?    A recently published study from Joanne Clarke, a PhD student at the University of Glasgow, and colleagues suggests that there might be a way to make the practice less damaging. Continue reading “How deep is too deep for commercial fishing?”

Fisheries, Aquaculture, & Sustainable Seafood

Reducing bycatch of skates and rays – stop tickling them!

Bottom-trawl fisheries may supply us with much of the tasty fish we like to enjoy, but it does come with its problems.  Also known as ‘dragging’, bottom trawling essentially involves dragging a large net, held open either with a beam (beam trawling) or large metal/wooden ‘doors’ (otter trawling) along the sea bed, or just above it.  It is used to catch a range of commercial species like cod, shrimp, flounder, and halibut.  One of the problems of trawling is that it is not a very selective form of fishing.  Other species are caught in the process, and this bycatch can include at risk species such as skates, rays and sharks.  As well as ecological implications, bycatch can be bad for fishers, who often end up throwing away bycatch either because it isn’t worth anything, or because they are not allowed to land it.  Bycatch reduction is a win-win for fishers and for the marine life caught.

Reducing bycatch of sharks, rays, and skates (collectively known as elasmobranchs) in bottom trawls is one of the many fishery-related issues on the mind of scientists at Marine Scotland Science.  As this piece of research from the Marine Scotland Science team shows, one possible solution (though not perfect) may not be all that tricky to implement. Continue reading “Reducing bycatch of skates and rays – stop tickling them!”

Climate Change, Acidification, & the Oceans, Fisheries, Aquaculture, & Sustainable Seafood

Climate Change Impacts on Kenya’s Fishery-dependent communities

 We now have a number of scientific studies that tell us how climate change is altering coral reef ecosystems, but how will these changes impact on communities that depend on them for their livelihood?  According to Joshua Cinner of James Cook University in Australia and colleagues from around the world, that answer depends more on the  community capacity for adaptation than its location.

Fishery-dependent communities in Kenya are not in a great situation.  Their reefs were heavily affected by a massive bleaching event in 1998 that has been linked to an extreme El Niño event and have not necessarily recovered as well as we might hope, and Kenyan reefs are likely to face increasing amounts of climate-related stress into the future.  Across three years, Cinner and co surveyed 15 ecological sites associated with 10 coastal communities along the Kenyan coast.  Using a range of ecological indicators of vulnerability of these reefs, they linked up the ‘health’ of the ecosystems with the vulnerability of the human communities that depend on them. Continue reading “Climate Change Impacts on Kenya’s Fishery-dependent communities”