Biologist questions aquaculture ecosystems

West Hawaii Today
Biologist questions aquaculture ecosystems

Aquaculture is supposed to take the pressure off ocean fish stocks and help avert a global food shortage, but Kohala resident and microbiologist Wendy Minor believes some forms of fish farming may be creating more problems than they are solving.

During the Kawaihae Local Resource Council's monthly meeting Sunday, Minor shared her thoughts on fish farming based on her 42 years of owning and operating independent labs that test food, water, wastewater and animals feeds.

As a triathlete and outrigger canoe paddler, this keynote speaker enjoys the ocean regularly and cares deeply about what happens to it because she wants it be in the same state or better for her granddaughter.

The fundamental paradox of many current forms of aquaculture is its reliance on wild fish for feed ingredients. Small fish, such as herring, anchovy, sardines and mackerel, are used either whole or as byproducts, then reduced into fish meal and fish oil to feed several aquaculture species, Minor said.

Fish food and fish meal are not the same thing. Fish food is a mix of fish parts with other types of agricultural products, including corn, soy and animal parts (chicken feathers and slaughter waste). Fish meal is "a pretty nasty product" and, depending on where the fish comes from, it can be contaminated with chemicals and pollutants, Minor said.

There are no strict regulations on how these products are made and the buyer typically tells the producer what's needed. The certificate of analysis is used to show the product meets certain specifications, usually the buyer's requirements, and that some testing was done, but "it's not worth the paper it's made on," Minor said.

Minor equated feeding wild fish to farmed fish to a hamster running on a wheel. She called this practice "unsustainable and inefficient." She's also concerned about the consequences of feeding farmed fish things not in their natural diet.

Not all aquaculture species affect fish supplies. For example, oysters and other filter-feeding mollusks can actually clean the water, as they feed on algae and nutrients that negatively affect water quality, she said.

Throughout her hour-long talk, Minor expressed concerns about the potential increase of nutrients and the prevalence of disease caused by fish farms. She said disease is closely associated with the density of the fish in the cages, pens or other containers.

"No matter if it's fish, animals or people, it's well-known that crowding increases the risk of disease outbreaks," she said. "Farmed fish are going to have disease and share pathogens or parasites like sea lice. What happens if these fish escape?"

When it comes to water quality, Minor thinks there's "a lack of standards for aquaculture." She likened open ocean fish farms to cities without sewage treatment plants.

Minor wasn't surprised when the Woods Institute for the Environment at Stanford University found relatively high concentrations of dissolved waste from fish farms do not dilute immediately and their concentrated waste plumes could travel significant distances to reach coastlines.

When a main sewage line in Waikiki broke and raw sewage was pumped into the Ala Wai Canal, she said "it hung together for a long time in the ocean" and could be detected at various places weeks later, including in sand one mile offshore.

Diane Kanealii, of the Kailapa Community Association, mentioned the Western Pacific Regional Fishery Management Council is discussing offshore aquaculture management at its meeting Friday in Honolulu. Those interested in commenting on this issue should e-mail their testimony today to or fax it to 522-8226.

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