Legislation Works: How Conservation Laws Have Saved Species
Biologists observed several hundred nesting pairs of California brown pelicans lay nests on West Anacapa Island, California in the spring of 1970. Normally, brown pelican eggs have a 70 percent chance of hatching, but this year only one chick survived. What happened?
DDT and its bioaccumulation in pelicans is what happened. Because of DDT in their tissue, pelican eggshells were thin and prematurely breaking. DDT interferes with calcium deposition and egg development in all birds, but fish-eating predators such as pelicans are especially prone to accumulating the pesticide. It was not just brown pelicans whose eggs were cracking due to DDT – so too were the eggs of the American bald eagle, ospreys, the golden eagle, peregrine falcons, and white pelicans. Without successful reproductions, populations of these predatory birds were plummeting, and extinction was an imminent possibility.
Biologists and policymakers alike charged into action. In 1966 Congress passed the Endangered Species Preservation Act. This created pathways to identify animals and plants as endangered or threatened and to establish protection measures to recover their populations. Brown pelicans were listed under the Endangered Species Act (ESA) in 1970. Year years later, DDT was banned throughout the United States by the Environmental Protection Agency. Many people thought the action was too late or a lost cause. But it wasn’t.
In the 1980s nesting success increased with an average of 900 nest attempts on Anacapa; this grew to an average of 4,600 annual nest attempts over 1985 to 2006. Then in 2009, the population was so robust the species was removed from the ESA list, or ‘delisted.’ At present there are over 70,000 nesting pairs throughout the state.
In 1967, the ESA’s first year, 78 species were listed: 14 mammals, 36 birds, 3 reptiles, 3 amphibians, and 22 fishes. In 1973 this evolved law into the Endangered Species Act, which still is in place today.
The ESA benefited several other iconic marine species found off the coast of California. Gray whales were also listed under the ESA in 1970. Commercial whaling had knocked their population down to an estimated low of 4,000-5,000 in the Eastern North Pacific. Targeted recovery strategies were deployed to reduce the number of whales killed annually and rebuild their population. These included boat distance requirements, shifts in shipping channels, and fishing gear restrictions. The success of the measures was so significant for gray whales in the Eastern North Pacific that they were ‘delisted’ in 1994. This is wonderful progress, but more should be done to continue to protect them. Changing environmental conditions including reduced Arctic sea ice and warming waters are affecting gray whale food. Researchers have documented that this change in food then can result in gray whale emaciation, shifted migratory timing, and diminished reproduction. Ongoing protections will help build resilience against this future change and contribute to preservation of the population.
Gray whales and California pelicans have recovered because the ESA law specifically singled out those species for protection. Conservation laws can also protect areas or habitats as opposed to species. Passed in 1999 the Marine Life Protection Act (MLPA) is an area-based conservation regulation requiring the state establish a statewide, science-based network of marine protected areas (MPAs). Over the course of eight years, the state solicited input from the public on where to establish MPAs, or zones in the coastal waters where certain activities, such as fishing, are limited or prohibited. MPAs are a tool that benefit dozens of species at one time in a particular location. When established as part of network, as was done under the MLPA, they amplify their benefits to a larger region.
A network of 124 MPAs covering 16 percent of California’s waters was the result. Monitoring of key indicators was conducted within and outside of these MPAs. A decadal review – compiling and summarizing all those data – was released in 2023. It showed the MPAs are supporting bigger and/or more abundance fish and invertebrate populations, with variation by region. Some MPA areas also showed signs of greater resilience and quicker recovery to the marine heat wave of 2013-14. The Aquarium’s Marine Species Report Card uses some of the MPA monitoring data in its accounts on California sheephead, Garibaldi, kelp bass, purple sea urchin, and California spiny lobster. When you compare counts from inside a protected area and outside you can see the impact: inside has more.
The California MPA network is monitored regularly through series of surveys which count species at fixed locations within and outside of but adjacent to MPAs. The plots below show the data collected for kelp bass in the south coast of California at MPA sites (top chart) and outside, “reference sites” (bottom chart). The data show that since 1999 kelp bass are increasing within MPAs (4.7% growth trend) whereas in adjacent reference sites their populations are mostly stable.
These stories demonstrate the power of laws and regulation in rebuilding populations of species. Regulations’ effectiveness is often conditional on other factors, including simultaneous deployment of other conservation strategies and patience. Recovery of species is rarely immediate, but there is hope for the future.
