NMFS—operating through its headquarters, five regional offices, and six regional Fisheries Science Centers—and the eight Councils are responsible for managing approximately 470 fish stocks in federal waters across five geographic regions of the country (see fig. 1 for the NMFS region and Council boundaries). Federal waters generally extend from 3 to 200 nautical miles off the coast of the United States. In fiscal year 2016, NMFS’ budget for its fisheries science and management activities, such as conducting stock assessments and developing fisheries management guidance, was approximately $536.7 million, according to NOAA budget documents. NMFS has overall responsibility for collecting data on fish stocks and ocean conditions and for generating the scientific information necessary for the conservation, management, and use of marine resources. The agency’s six regional Fisheries Science Centers are the primary entities responsible for performing this work, and they collaborate with a variety of partners, such as coastal states, academics, other nations, and members of the fishing industry in doing so. For many fish stocks, the regional Fisheries Science Centers analyze the collected data to conduct stock assessments to estimate, among other things, the size of the population of a fish stock (i.e., the stock’s abundance) and other population dynamics. In addition, stock assessments contain information on reference points that can be used to inform management decisions. NMFS provides the results of its stock assessments and other analyses, as appropriate, to the Councils for use in implementing their respective fisheries management responsibilities. The Councils are responsible for a number of steps in the fisheries management process. In particular, the Councils develop and amend fishery management plans for fish stocks, based on guidelines developed by NMFS. Fishery management plans identify, among other things, the conservation and management measures that will be used to manage a fishery, such as fishing equipment restrictions, permitting policies, and restrictions on the timing or location of permissible fishing. The Magnuson-Stevens Act requires the conservation and management measures in fishery management plans to be based on the best scientific information available. The Councils submit proposed plans and plan amendments to NMFS, which is responsible for determining if they are consistent with the Magnuson-Stevens Act and other applicable laws, and for issuing and enforcing final regulations to implement approved plans. In implementing fishery management plans, the Councils are responsible for determining the maximum size of each fish stock’s allowable harvest. This is generally done by developing annual catch limits for each fish stock, that is, the amount of fish that can be harvested in the year. Figure 2 presents an overview of the federal fisheries management process. According to the 2014 Third National Climate Assessment, a number of physical and chemical changes to the oceans have been observed or are expected to occur as a result of climate change, largely attributable to increasing concentrations of greenhouse gases in the atmosphere, such as carbon dioxide. For instance, surface temperatures for the ocean surrounding the United States and its territories warmed by more than 0.9 degrees Fahrenheit over the past century, according to the 2014 assessment. Changes in ocean temperature have varied, with the oceans off the coasts of Alaska and parts of the northeastern United States, for example, warming more rapidly than other areas. The 2014 assessment notes that warming has several consequences and can lead to a number of other physical changes in the ocean, such as the thermal expansion of sea water, which may contribute to rising sea levels. Increases in ocean surface temperatures may also alter ocean circulation by reducing the vertical mixing of water that brings nutrients to the surface and oxygen to deeper waters, which could affect the availability of nutrients and oxygen for marine life in different locations, according to the 2014 assessment. Increasing levels of carbon dioxide in the atmosphere have also contributed to chemical changes in the oceans. According to the National Research Council, scientists estimate that the world’s oceans have absorbed approximately 30 percent of the carbon dioxide emitted by human activities over the past 200 years. As atmospheric concentrations of carbon dioxide increase, the amount of carbon dioxide in the oceans also increases. The increased uptake of atmospheric carbon dioxide is resulting in chemical changes in the oceans, including a decrease in the average pH of surface ocean waters (making seawater more acidic) and a reduction in the availability of minerals needed by many marine organisms to build shells and skeletons, according to the National Research Council. These chemical changes, known as ocean acidification, may pose risks for some marine species and ecosystems. For the purposes of this report, our discussion of the effects of climate change refers to both physical and chemical changes in the oceans. Broadly defined, risk management is a strategic process for helping decision makers assess risk, allocate finite resources, and take action under conditions of uncertainty, such as when faced with incomplete information or unpredictable outcomes that may have negative impacts. Risk management is an inherent part of fisheries management, as fisheries managers often make decisions based on incomplete data and in the face of uncertainty. Accounting for the potential effects of climate change injects an additional source of uncertainty and risk into the fisheries management process. The federal government has recognized the need to account for climate change risks in its planning and programs and has called on agencies to take certain actions. For example, the President issued Executive Order 13653 in 2013, directing federal agencies to develop or update comprehensive climate change adaptation plans that among other things identify climate-related impacts on and risks to an agency’s ability to accomplish its missions, operations, and programs and describe the actions the agency will take to manage climate risks. Subsequently, the Department of Commerce’s 2014 Climate Change Adaptation Strategy set a goal to incorporate climate information in the department’s resource management programs and policies and to take action to reduce vulnerabilities and increase resilience of marine and coastal natural resources. We have previously reported on risk management in the context of climate change and identified risks that climate change may pose in a variety of areas relevant to the federal government, such as infrastructure and federal supply chains. We found that leading risk management guidance recommends a sequence of activities that begins, in part, with identifying risks. Specifically, the International Organization for Standardization’s standards on risk management recommend that organizations such as federal agencies develop, implement, and continuously improve a framework for integrating risk management into their overall planning, management, reporting processes, and policies. These standards also state, among other things, that risk management should be a part of decision making and that it should be based on the best available information. We found that NMFS and the Councils have general information about the types of effects climate change is likely to have on federally managed fish stocks, but information about the magnitude and timing of effects for specific fish stocks is limited, based on the responses NMFS and the Councils provided to our questionnaire, our analysis of NMFS and Council documentation, and our interviews with NMFS and Council officials. In addition, NMFS and the Councils identified several challenges they face to better understand the effects of climate change, such as determining the extent to which a change in a fish stock’s abundance or distribution is caused by climate change, natural variation in the oceans, or other human or environmental factors. Through our analysis, we found that NMFS and the Councils have general information about the types of effects climate change is likely to have on fish stocks, but information about the magnitude and timing of effects for specific fish stocks is limited. In general, the types of effects climate change is likely to have include changes in fish stock abundance and distribution and the timing or location of biological events such as spawning (the process by which fish reproduce), according to NMFS and Council officials. These effects will not be uniform across fish stocks but rather will likely vary, with the abundance of some stocks being negatively affected and the abundance of other stocks increasing or not being affected, according to NMFS documentation. Similarly, potential shifts in distribution will vary, as some fish stocks may respond to changing ocean temperatures by moving north or to deeper waters in search of the water temperatures they are accustomed to, but shifts in other directions may occur as well. Some NMFS and Council officials said that changes in the timing and location of biological events are also expected to vary between fish stocks. For example, some fish stocks may spawn at different times or in different locations under warmer ocean conditions. In some instances, the abundance or distribution of fish stocks may shift in response to changes in ocean habitats occurring because of a changing climate. For example, reductions in seasonal sea ice cover and warmer ocean surface temperatures may open up new habitats in polar regions that could lead to shifts in distribution for some fish species, according to the 2014 Third National Climate Assessment. Furthermore, warming ocean temperatures and higher acidity levels also affect the health of coral reefs, which provide essential habitat for many fish stocks. The 2014 assessment reported, for example, that scientific research indicated that 75 percent of the world’s coral reefs were under threat from the effects of climate change and local stressors, such as overfishing, nutrient pollution, and disease. When water is too warm, corals will expel the algae living in their tissues, causing the coral to turn completely white—this phenomenon, known as coral bleaching, can cause coral to die or become more susceptible to disease, which can subsequently decrease their capacity to provide shelter and other resources for reef-dependent fish and other ocean life, according to the 2014 assessment. We found that NMFS and the Councils have limited scientific information about the magnitude and timing of potential climate change effects for most fish stocks they manage. For example, officials from one Council reported that they have very little scientific information specific to how climate change is currently affecting the fish stocks in their region, or how those stocks may be affected in the future, with the exception of some anecdotal information. NMFS and Council officials explained that scientific information is often lacking to quantify the magnitude and timing of effects for most individual fish stocks and that their ability to project future effects at the stock level is generally limited.