- What is the future of fishing and why is this the case? - Why is this especially important for New England? - What is currently being done about this? What are pro’s and con’s of this approach? Do Now

FISH IN A WAREHOUSE? How one Baltimore fish scientist could change the way we eat CHAPTER 14 FISHERIES AND AQUACULTURE

The industry devoted to commercial fishing, or the places where fish are caught, harvested, processed, and sold. WHAT IS A FISHERY?

over 15% of the world population rely on fish as their main source of protein poorer nations – fish is cheaper than other meat Because humans rely on fish protein. This reliance on fish spawns a huge global fishing industry – 200 million people and a revenue of $130 billion wealthier nations – fish is part of a health-conscious diet due to the omega-3 fatty acids found in cold saltwater species WHY ARE FISHERIES SO IMPORTANT?

WHAT IS A COLLAPSED FISHERY? But the oceans pay a price for the health and economic benefits that fish provide humans.

A collapsed fishery is when in a commercial fishery the annual catches fall below 10% of their historic high.

A collapsed fishery reflects a combination of factors: technological advances increasing demand for fish tragedy of the commons discounting future value WHAT CAUSES A FISHERY TO COLLAPSE?

enables fishers to travel further into the ocean, catch more fish, and transport them greater distances than ever before to meet market demand steam engines, flash freezing, and trawler ships that could drag huge nets behind them Technological advances feed the increasing demand for fish this leads to declines in fish stock

Additional consequences of technology: Pollution – from increased fishing traffic Bycatch – the capture of non-target species often exceeds the target species catch Damage to the sea bed – trawling damages ecosystems and spawning grounds

Tragedy of the commons discounts the future value of fish As nobody owns the ocean, the choice is simple for an individual fisher: “If I don’t take it, someone else will.” It doesn’t make sense to leave any fish behind, when the immediate value of taking the fish is greater than the immediate cost—even if it means fewer fish to harvest in the future This leads to overuse and harm to fish stock without regard for the future

COMMERCIAL FISH CATCH IN NEWFOUNDLAND-LABRADOR SHELF This could mean that we may not be able to harvest fish this way for much longer.

WHAT IS THE CURRENT STATUS OF MARINE FISHERIES?

WHAT IS MAXIMUM SUSTAINABLE YIELD (MSY)? The amount of fish that can be harvested without decreasing the yield in future years.

Currently, 68% of the global marine fisheries are sustainably fished. If so, then what is the problem? The other 32% of global marine fisheries are overexploited, and this number has increased threefold since the 1970s.

WHAT IS AN OVEREXPLOITED FISHERY? A fishery in which more fish are harvested than is sustainable in the long run, leading to population decline and possibly a depleted fishery.

WHAT IS A DEPLETED FISHERY? A depleted fishery is when the fish population is well below historic levels and the population’s reproductive capacity is low, meaning that recovery will occur slowly, if at all.

With the loss of higher trophic level species like cod, fishers pursue the herring, crabs, and shrimp at lower trophic levels – called “fishing down the food chain.” WHAT ARE THE CONSEQUENCES OF DEPLETED FISHERIES?

Declining fish populations impact ecosystems – especially those with simple food webs. Declines in cod and their prey increase hydroid populations making it hard for cod to recover as they eat the same food as young cod, and also feed on the juvenile cod. When cod are depleted, fishers move down the food chain and pursue cod prey, thereby reducing food supply for the cod, and jeopardizing its recovery.

Exclusive economic zones zones that extend 200 nautical miles from the coastline of any given nation, where that nation has exclusive rights over marine resources, including fish Marine protected areas discrete regions of ocean that are legally protected from various forms of human exploitation WHAT ARE SOME POTENTIAL SOLUTIONS TO PROTECT FISHERIES?

However, many scientists say that the real solution to our fish problem won’t be found in the ocean at all. Marine reserves restricted areas where all fishing is prohibited and absolutely no human disturbance is allowed. Sustainable fishery fishing that ensures fish stocks are maintained at healthy levels, the ecosystem is fully functional, and fishing activity does not threaten biological diversity

Aquaculture, or fish-farming, is the rearing of aquatic species in tanks, ponds, or ocean net pens. WHAT IS AQUACULTURE?

Aquaculture provides more than half of all seafood consumed world wide. But, they come along with many environmental challenges. WHAT ARE THE POTENTIAL PROBLEMS WITH AQUACULTURE?

Aquaculture: Problems and Solutions

Another solution to the problems of conventional aquaculture is to move it indoors. WHAT IS A RECIRCULATING AQUACULTURE SYSTEM (RAS)?

A recirculating aquaculture system produces fish in indoor tanks where the environment is controlled through water treatment and recirculation. HOW DOES RAS WORK?

REQUIRED PROCESSES IN RAS Fish culture tank Waste solids removal Aeration or oxygenation Temperature, salinity, and pH Fine and dissolved solids removal Carbon dioxide removal Disinfection Biological filtration (nitrification)

HOW DOES RAS MEASURE UP TO OPEN WATER AQUACULTURE?

RAS has several OPERATIONAL advantages over open water systems: The system can be sized as needed. The system can raise marine species independent of location of the aquaculture operation. Conditions in the tanks can be precisely controlled to suit a specific species of fish.

The system is biosecure—there is no risk of the fish from RAS operations escaping into the wild. As they are indoors, they reduce habitat loss The fish growing in RAS tanks require less food per pound, and convert it into flesh at a much higher ratio. RAS has several ECOLOGICAL advantages over open water systems: Reducing the distance between the fishery and the consumer means less energy spent on transportation and cold storage

RAS employs carefully calibrated microbial communities to manage waste in which the bacteria convert some 96% of the solid waste into fuel-grade methane RAS uses waste to produce energy:

However, marine aquaculture presents some unique challenges. For one, most commercially important marine fish—such as sea bream, sea bass, and tuna—do not reproduce in captivity.

Clicker Question How did Dr. Zohar get his captive fish to spawn and reproduce? a. He changed the lighting to mimic outdoor lighting cycles. b. He controlled the levels of interactions among the fish. c. He carefully controlled the salinity regimes in the tanks. d. He injected the fish with hormones.

RAS is better suited to certain regions of the world. RAS technology is complex and expensive to set up and operate. not feasible in poorer regions of the world not feasible in water-starved areas As the type of fish grown can be chosen based on economic opportunity rather than location, such a system is potentially well-suited for markets in developed countries, like the US.

“We have to make a distinction between having an impact and being sustainable. Anything you do is going to have an impact on the environment. The real question is whether it’s an impact the environment can absorb and recover from or one that will do permanent damage” - Lorenzo Juarez