By: Rod Fujita & Doug Rader
People have been catching fish for thousands of years, so you’d think by now we would have a pretty good idea of how fisheries are doing. However, the two most basic numbers that you need to answer that question – how many fish are in the sea, and how many are being caught – have been highly uncertain.
A new study published in Nature by researchers at the University of British Columbia finds that the number of fish in the sea has been underestimated, and that the world’s fisheries should be more closely monitored. We couldn’t agree more.
It’s critically important for scientists to estimate these numbers so we can tell whether catch is too high, too low, or just right. The stakes are enormous: these numbers and trends will determine what management actions are necessary to ensure that fisheries can continue to provide healthy food for billions of people and provide livelihoods for tens of millions. Read More
Photo: Kennedy Warne
All who enjoy the wild biodiversity of the seas should take a moment this week to mark the passing of Dr. Bill Ballantine, the Founding Father of what has become a fast-growing global network of marine protected areas.
The science of setting aside unique sanctuaries from development is an art that dates back centuries – at least on land. America’s own federally designated national parks, wildlife refuges, and forest reserves can be traced to the mid-1800s.
But ocean protection is a relatively recent phenomenon, emerging only in the late 1970s. And it’s arguably more difficult to know how to chart, value and protect life that is hidden from view. Read More
Fishing shack along a mangrove channel, Brazil
I recently visited Brazil for the first time to work with our partners in Fish Forever to choose sites to work in over the next several years, with the goal of turning fisheries with declining yields and profits into success stories for fishermen, their communities, and the environment. Fish Forever is a partnership between Rare, the University of California at Santa Barbara, and the Environmental Defense Fund.
Brazil’s 300,000 square mile shelf produced about 550,000 tons of seafood in 2011, worth over $US 1.5 billion, and employs about 1 million people according to the Food and Agriculture Organization (FAO). Read More
Healthy sponge in the Gardens of the Queen, Cuba. Photo: Noel Lopez Fernandez
Coral reefs seem delicate, but when they are healthy they can take a lot of abuse. I’ve seen corals recover from severe hurricanes and even volcanic eruptions. But coral reefs can also transition suddenly from colorful, vibrant ecosystems to mere shadows of themselves. Decades of scientific investigation have shed a lot of light on this, and in a recent publication, my colleagues and I summarize a lot of the data that have been collected on Caribbean coral reefs to identify where these dangerous “tipping points” are. This work is part of the Ocean Tipping Points project, a collaboration between several institutions aimed at finding tipping points in all kinds of marine ecosystems so that managers can implement measures that will keep these ecosystems well away from the brink. Read More
(c) Jim Patterson Photography, https://jimpattersonphotography.com/
By: Rod Fujita & Kendra Karr
Fisheries management is principally focused on managing fishing pressure, with the goal of keeping individual fish stocks healthy enough to produce good yields. But fisheries also affect the basic processes that keep ocean ecosystems healthy. This is why it is important to understand how many fish need to be in the system to maintain the many important services that an ocean ecosystem can produce — including the maintenance of biodiversity, tourism value, and fisheries — and to manage fisheries so that fish populations remain at about that level.
The evidence that fish are important regulators of ecosystem processes is particularly strong in coral reefs. The abundance and variety of fish is one of the most striking aspects of a healthy coral reef. Some species transport energy and nutrients between seagrass meadows and the reefs. Grazing fish species on a healthy coral reef keep seaweeds that would otherwise over-grow the reef in check. Predators regulate populations of prey species, responding to natural variability by adjusting their feeding rates and numbers. On a healthy reef, many different species occupy each of these niches, and each does their job in a slightly different way. This enables the reef to resist threats and other changes (like hurricanes) and to recover from very storms or human impacts, within limits of course. Read More
Recently, the impacts of climate change on fisheries have been in the news. The emphasis has been on the inability of scientists to explain how climate change is affecting fisheries or to fix the problems it seems to be causing. These include shifting distribution and abundance patterns of commercially valuable fish stocks – shifts that may leave fishermen stranded with very restrictive catch limits, even when they have been doing everything possible to protect and restore their stocks. These problems are being felt acutely in New England, where catch of some valuable stocks has been highly restricted to rebuild stocks depleted by overfishing – but they face even more restrictions as scientists find less fish in the water, possibly due to migrations induced by climate change.
A better scientific understanding of how climate change influences the distribution and abundance of fish is certainly needed, but that may be less important than the need for more flexible human institutions that can rapidly adjust to those changes. Read More