Eating wild caught fish is better for the environment and biodiversity than consuming meat or crops, says leading international marine scientist Professor Ray Hilborn.

Fish is the perfect protein, he told a Deepwater Group fisheries symposium in Wellington on 16 February.

Hilborn, professor of aquatic and fishery science at the University of Washington in the US, said fish is a healthy, animal-sourced protein that can be enjoyed without polluting the air and water, without drying up our rivers, without draining the life from soil, without causing our planet to warm even more and without adversely impacting on diabetes, heart disease and cancer rates.

“Fish can be caught with almost no water use, no herbicides or pesticides, no antibiotics and no soil erosion,” he said.

“All crops and almost all non-grazing livestock production depend on eliminating natural ecosystems and replacing them with fields of monoculture crops. Biodiversity is largely eliminated.

“The two major environmental impacts of fishing are greenhouse gases primarily from fuel use and on biodiversity.

“The greenhouse gas footprint of fisheries varies enormously and depends almost totally on fuel use. The most fuel-efficient fisheries are those that go after dense schools of fish such as mackerel, herring and pollock and in New Zealand southern blue whiting and hoki. These fuel-efficient fisheries have a much lower greenhouse gas footprint than livestock and can be as low as some crops.

“We have all heard that the oceans are being emptied of fish and a common view is that fishing has more biodiversity impact than livestock or crops.

“Nothing could be further from the truth. A key difference between fisheries and crops is that fisheries target specific species and leave the base of the marine food chain (phytoplankton and zooplankton) alone.

“Fisheries certainly affect the abundance of the target species, and some non-target species, but usually affect only a small portion of the species in the sea.”

Several studies published in the journals Conservation Letters, Marine Ecology Progress Series and Scientific reports, including two by Hilborn and co-authors, have shown the total abundance of fish in the sea is either unchanged or even higher because of fishing.

“This is because fisheries tend to target predatory fish,” Hilborn said.

“Because the small forage fish are naturally far more abundant than their predators, their increase more than compensates for the reduction of the predators.

“We are certainly not going to run out of fish in sustainable, well-managed fisheries like that of New Zealand.

Other authors published in the Proceedings of the National Academy of Sciences found the two major threats to ocean ecosystems were climate change and  coastal impacts from sediment, pollution and habitat loss.

“Fisheries were the impact of least concern,” Hilborn said.

“Fisheries target specific species and leave the base of the marine food chain alone.

“Wild capture fisheries across almost all environmental impacts are more environmentally friendly than livestock or crops.”

Ray Hilborn is Professor of Aquatic and Fishery Science at the University of Washington. He was the keynote speaker at the 2023 Symposium on Seafood Production.