Understanding U.S. Maritime Zones: Territorial Waters vs. Exclusive Economic Zones

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The ocean covers more than 70% of Earth’s surface, but not all waters are created equal under international law.

When you see a U.S. Coast Guard cutter patrolling off the California coast or read about offshore wind farms being built in federal waters, you’re witnessing the complex system of maritime zones that govern how nations control their surrounding seas.

The United States controls vast areas of ocean through two primary zones: the Territorial Sea, where America exercises full sovereignty much like it does on land, and the Exclusive Economic Zone (EEZ), where it has specific rights to natural resources. These zones determine everything from where foreign ships can travel to where oil companies can drill and where fishing boats can cast their nets.

The 1982 United Nations Convention on the Law of the Sea established the framework for these maritime zones. While the United States hasn’t formally joined this treaty, it follows most of its provisions as accepted international law.

Understanding these maritime zones helps explain major policy decisions, from the Biden administration’s push for offshore wind development to ongoing tensions with China over South China Sea navigation. They also reveal why certain international incidents make headlines while others barely register in the news.

Where Maritime Zones Begin

The Baseline

Every maritime zone starts from the same reference line: the baseline. In most places, this is simply the low-water line along the coast as marked on official NOAA nautical charts. The baseline also includes legally defined lines across river mouths and bays.

The U.S. Baseline Committee, led by the State Department, carefully reviews and approves where these lines are drawn. This interagency body includes representatives from NOAA, the Coast Guard, and other federal agencies with maritime interests.

Getting the baseline right matters because every other maritime zone is measured from it. Move the baseline seaward by just a few hundred yards, and you potentially shift the outer boundary of the EEZ by the same distance 200 miles offshore. For a nation with as much coastline as the United States, these technical decisions can affect millions of square miles of ocean jurisdiction.

Historical Context

The concept of maritime zones evolved over centuries. Ancient Rome claimed the Mediterranean as “Mare Nostrum” (Our Sea), while medieval European states often claimed jurisdiction only as far as they could see from shore. The Dutch legal scholar Hugo Grotius argued in 1609 for “freedom of the seas,” while others insisted on coastal state control.

The “cannon shot” rule emerged in the 18th century as a practical compromise—states could claim waters as far as they could defend them with shore batteries. This typically meant about 3 nautical miles, though the exact distance varied by country and sometimes by the type of cannon available.

The Territorial Sea: America’s Ocean Territory

What It Is

The Territorial Sea extends up to 12 nautical miles from the baseline. One nautical mile equals about 1.15 land miles or 1.852 kilometers. This zone is essentially an underwater extension of U.S. territory.

For centuries, many nations including the United States claimed only 3 nautical miles, based on the old “cannon shot” rule. But as naval technology advanced and nations sought greater security buffers, pressure grew for wider territorial seas. Some countries began claiming 12 miles, others 6 miles, creating a patchwork of different claims worldwide.

The 1958 Geneva Convention on the Territorial Sea failed to establish a uniform limit. Iceland’s “Cod Wars” with Britain in the 1960s and 1970s partly stemmed from disputes over fishing limits and territorial waters. As international consensus shifted toward 12 miles, the U.S. adapted. Presidential Proclamation 5928 in 1988 officially extended America’s Territorial Sea to 12 nautical miles.

This change wasn’t just symbolic. It meant U.S. jurisdiction expanded from about 87,000 square miles of territorial waters to roughly 350,000 square miles—an area larger than Texas.

Full Sovereignty

Within its Territorial Sea, the United States exercises complete sovereignty. This means the same authority it has over land extends into these waters, the airspace above them, and the seabed below.

The U.S. can:

• Regulate all activities, from commercial fishing to recreational boating
• Enforce every domestic law, from criminal statutes to environmental regulations
• Control which foreign vessels enter and under what conditions
• Explore and exploit any resources, including oil, gas, and marine life
• Build artificial islands and structures like bridges or offshore platforms
• Prohibit foreign aircraft from flying overhead without permission
• Establish shipping lanes and traffic separation schemes
• Require pilots for foreign vessels entering ports
• Inspect vessels for safety and security compliance

This comprehensive control provides a critical security buffer around America’s coastline. The extension of sovereignty to the airspace prevents unauthorized overflight by foreign aircraft, while sovereignty over the seabed means the U.S. has exclusive rights to any mineral or living resources found there.

Legal Complexities

The territorial waters concept isn’t as straightforward as it might seem. Different U.S. laws sometimes use different definitions of territorial limits, creating potential confusion.

For example, the Clean Water Act defines U.S. territorial seas as extending only 3 nautical miles for certain regulatory purposes, even though the general territorial sea limit is 12 miles. The Army Corps of Engineers uses the 3-mile limit for some permitting decisions under Section 404 of the Clean Water Act.

These discrepancies reflect the layered nature of U.S. law, where older statutes may persist even as broader policy evolves. Courts sometimes have to determine which definition applies in specific cases, particularly for environmental regulations or criminal prosecutions.

Foreign Ships’ Rights

The main limitation on U.S. control in the Territorial Sea is the right of “innocent passage” for foreign ships. This carefully balanced principle allows ships to transit through territorial waters under specific conditions.

Passage must be continuous and expeditious—no loitering allowed. Ships can stop only if necessary for normal navigation, to render assistance to persons in distress, or due to force majeure (unforeseeable circumstances). Most importantly, the passage must be “innocent,” meaning it doesn’t threaten the peace, security, or good order of the coastal state.

UNCLOS Article 19 lists activities that make passage non-innocent, including:

• Any threat or use of force against the coastal state
• Weapons exercises or military maneuvers
• Intelligence gathering activities
• Propaganda activities affecting coastal state defense
• Military aircraft operations (launching, landing, or taking aboard)
• Fishing activities
• Research or survey activities
• Serious pollution contrary to international law
• Any other activity not directly related to passage

The innocent passage right applies to all ships, including warships. However, some coastal states require advance notification or authorization for warship passage, though this isn’t universally accepted. If a warship ignores coastal state regulations during passage, it can be ordered to leave territorial waters immediately.

Submarines must navigate on the surface and show their flag during innocent passage. This requirement, obviously, has significant implications for naval operations.

Notably, there’s no innocent passage right for aircraft. Any foreign plane flying over the Territorial Sea needs U.S. permission. This asymmetry between surface vessels and aircraft reflects the greater potential threat and speed associated with airborne intrusions.

Practical Applications

The territorial sea concept plays out in real-world scenarios regularly. When Iranian speedboats harass U.S. Navy ships in the Persian Gulf, the location matters enormously—are they in Iranian territorial waters, international waters, or somewhere in between?

Similarly, when Chinese vessels shadow U.S. Navy ships in the South China Sea, the question of whose territorial waters they’re in (if any) determines what actions are legal under international law. The U.S. Freedom of Navigation Operations (FONOPS) specifically challenge what America considers excessive maritime claims by other nations.

The Exclusive Economic Zone: America’s Resource Domain

A Massive Ocean Territory

The Exclusive Economic Zone stretches up to 200 nautical miles from the baseline, encompassing waters beyond the Territorial Sea. President Reagan established the U.S. EEZ through Presidential Proclamation 5030 in 1983.

Reagan’s proclamation was carefully timed. UNCLOS negotiations were concluding, but the treaty wouldn’t enter force until 1994. By proclaiming the EEZ early, the United States signaled its intent to claim these rights under emerging customary international law, even without joining the formal treaty.

The U.S. EEZ is enormous—over 3.4 million square nautical miles, larger than the combined land area of all 50 states. This makes it one of the world’s largest EEZs and a repository of immense natural wealth. Only France, with its far-flung overseas territories, has a larger EEZ.

To put this in perspective, the U.S. EEZ is roughly:

• Twice the size of Russia’s land territory
• Larger than China, India, and the United States combined
• About the size of the entire continent of Australia
• Equivalent to nearly 30% of the Pacific Ocean

The EEZ Revolution

The EEZ concept represented a dramatic shift in ocean law. Before the 1970s, coastal states generally controlled only narrow territorial seas, with everything beyond being high seas open to all nations. The EEZ brought an estimated 38% of the world’s oceans under some form of national jurisdiction.

This change was driven by several factors:

• Developing nations’ desire to control valuable resources off their coasts
• Advances in offshore drilling technology making deep-water resources accessible
• Growing concern about overfishing by distant-water fleets
• The “common heritage of mankind” concept that sought to share deep-sea resources globally

The EEZ compromise gave coastal states resource rights while preserving navigation freedoms essential to global commerce and naval mobility.

Sovereign Rights, Not Full Sovereignty

The EEZ represents a carefully crafted compromise in international law. Unlike the Territorial Sea, coastal states don’t have full sovereignty here. Instead, they have “sovereign rights” for specific purposes, primarily related to natural resources.

The United States has sovereign rights in its EEZ for:

• Exploring, exploiting, conserving, and managing living resources (fish, marine mammals, etc.)
• Exploring and exploiting non-living resources of the seabed and subsoil (oil, gas, minerals)
• Economic activities like offshore wind farms, wave energy projects, and ocean thermal energy conversion
• Regulating biotechnology and genetic resources from marine life

The U.S. also has jurisdiction over:

• Artificial islands, installations, and structures (oil platforms, wind turbines, research stations)
• Marine scientific research
• Environmental protection measures
• Safety of navigation in designated areas

This jurisdiction allows the United States to set conditions for how activities are conducted, require environmental impact assessments, and establish safety zones around installations.

Resource Rights in Practice

The distinction between “sovereign rights” and “sovereignty” has practical implications. Sovereign rights are functional—they apply to specific activities rather than general governance. This means:

The U.S. can:

• License oil and gas exploration and production
• Set fishing quotas and seasons
• Require environmental permits for seabed mining
• Establish marine protected areas for conservation
• Regulate offshore wind farm construction
• Control scientific research related to resource assessment

The U.S. cannot:

• Stop foreign ships from transiting the area
• Prevent foreign aircraft from flying overhead
• Enforce general criminal law against foreign flagged vessels (except for resource-related crimes)
• Impose taxes on foreign vessels simply for being in the area
• Require advance permission for military activities unrelated to resources

Other Nations’ Freedoms

Other countries retain important freedoms in the U.S. EEZ that they don’t have in the Territorial Sea:

Freedom of Navigation: Foreign ships, including military vessels, can navigate through the EEZ for any lawful purpose. This includes merchant vessels carrying cargo, naval ships conducting operations, and fishing vessels transiting to other areas.

Freedom of Overflight: Foreign aircraft can fly over the EEZ without U.S. permission. This is crucial for international aviation, as many flight paths cross EEZs. Military aircraft also retain overflight rights, though they must respect safety regulations and avoid interfering with authorized activities.

Freedom to Lay Cables and Pipelines: Essential for global communications and energy transport. The internet relies heavily on undersea cables that often cross multiple EEZs. While foreign states have this right, the U.S. can set conditions for infrastructure connected to its continental shelf activities.

Military Activities: This is perhaps the most controversial retained freedom. Major naval powers, including the United States, insist that military activities unrelated to resource exploitation remain legal in EEZs. Some coastal states disagree, arguing that certain military activities (like intelligence gathering or weapons testing) violate their sovereign rights.

These freedoms were crucial for getting major maritime powers to accept the EEZ concept. They ensure continued global commerce and military mobility while giving coastal states control over valuable resources.

Balancing Competing Interests

The “due regard” principle requires both coastal states and other nations to consider each other’s rights. In practice, this means:

For the United States as a coastal state:

• Cannot arbitrarily interfere with lawful navigation or overflight
• Must allow reasonable access for cable laying
• Should avoid unnecessarily restrictive regulations on transit activities

For other nations in the U.S. EEZ:

• Must respect U.S. resource management measures
• Cannot interfere with authorized U.S. activities like oil drilling or wind farming
• Should comply with reasonable environmental and safety regulations

Disputes sometimes arise when these principles conflict. For example, if seismic surveys for oil exploration interfere with submarine cable routes, or if military exercises conflict with fishing seasons.

Key Differences at a Glance

The Contiguous Zone: A Law Enforcement Buffer

Between the Territorial Sea and the broader EEZ lies the Contiguous Zone, extending from 12 to 24 nautical miles from the baseline. The United States proclaimed this zone in 1999.

This zone serves a specific law enforcement purpose rooted in practical necessities. Before modern radar and satellite surveillance, customs and immigration authorities needed additional space to intercept smugglers and illegal immigrants before they reached territorial waters.

Enforcement Powers

The U.S. can take action in the Contiguous Zone to:

• Prevent violations of customs laws (stopping smuggling operations)
• Prevent immigration law violations (intercepting vessels carrying undocumented migrants)
• Prevent fiscal law violations (tax evasion, duty avoidance)
• Prevent sanitary law violations (quarantine enforcement, disease control)
• Pursue vessels that have already violated these laws in U.S. territory or territorial waters

The Contiguous Zone also allows the U.S. to protect underwater cultural heritage, such as shipwrecks and archaeological sites, from unauthorized salvage or artifact removal.

Real-World Applications

Coast Guard operations in the Contiguous Zone often involve:

• Intercepting drug smuggling vessels before they reach territorial waters
• Conducting migrant interdiction operations, particularly in the Caribbean and off Florida
• Pursuing vessels that have violated customs laws and are attempting to escape to international waters
• Protecting archaeological sites like Civil War shipwrecks from treasure hunters

Unlike the Territorial Sea, the Contiguous Zone doesn’t grant airspace or resource rights. It’s purely a functional zone for specific types of law enforcement.

Hot Pursuit

The Contiguous Zone also facilitates “hot pursuit” operations. Under international law, if a foreign vessel violates laws within territorial waters and then flees, the coastal state can pursue it into international waters under certain conditions. The pursuit must be continuous and must have begun while the vessel was still in territorial waters or the contiguous zone.

Managing America’s Ocean Wealth

Living Resources and Fisheries

The waters of the U.S. EEZ support fisheries worth hundreds of billions of dollars annually to the U.S. economy. American fisheries provide food security, support coastal communities, and contribute significantly to the nation’s protein supply.

The Magnuson-Stevens Fishery Conservation and Management Act governs how these resources are managed. This 1976 law, originally called the Fishery Conservation and Management Act, was groundbreaking in extending U.S. jurisdiction over fisheries from 12 miles to 200 miles offshore.

Regional Management Structure

The law established eight Regional Fishery Management Councils that develop plans for specific fisheries:

New England: Managing cod, haddock, lobster, and other groundfish species Mid-Atlantic: Overseeing summer flounder, scup, black sea bass, and surf clam fisheries South Atlantic: Managing snapper, grouper, and coastal migratory species Caribbean: Controlling tropical reef fish and spiny lobster fisheries Gulf of Mexico: Overseeing red snapper, grouper, and shrimp fisheries Pacific: Managing salmon, groundfish, and highly migratory species North Pacific: Controlling Alaska’s valuable pollock, crab, and salmon fisheries Western Pacific: Managing fisheries around Hawaii, American Samoa, and other Pacific territories

These councils include federal and state officials plus private citizens with fisheries expertise—boat captains, processing company executives, marine scientists, and environmental advocates. This structure ensures that management decisions reflect both scientific advice and practical fishing experience.

NOAA Fisheries provides scientific support through stock assessments, develops federal regulations, and enforces conservation measures. The agency operates research vessels, conducts fish population surveys, and maintains databases of catch and fishing effort.

Stock Assessment and Quotas

Modern fisheries management relies heavily on stock assessments—scientific evaluations of fish population size, reproduction rates, and fishing mortality. These assessments use data from:

• Commercial fishing vessel logbooks
• Observer programs that place scientists on fishing boats
• Independent scientific surveys using research vessels
• Fish tagging and electronic monitoring programs
• Genetic sampling to understand population structure

Based on these assessments, managers set Total Allowable Catches (TACs) and allocate them among different user groups. The allocation process can be contentious, as commercial fishermen, recreational anglers, and charter boat operators often compete for shares of the same resource.

Success Stories and Ongoing Challenges

The Magnuson-Stevens Act has produced notable conservation successes. Striped bass populations along the Atlantic coast recovered from near-collapse in the 1980s through cooperative federal-state management. Summer flounder, scup, and other Mid-Atlantic species have also rebuilt from overfished status.

However, challenges remain:

• Climate change is shifting fish distributions, with some species moving north as waters warm
• Ocean acidification threatens shellfish and other calcifying organisms
• Pollution from land-based sources affects fish habitat
• Interactions between fisheries and protected species like sea turtles and marine mammals
• International coordination for highly migratory species like tuna and billfish

International Fisheries Issues

Some of the most valuable fisheries involve species that migrate across national boundaries or spend part of their lives in international waters. Pacific salmon spawn in U.S. rivers but mature in the ocean, often crossing into Canadian or international waters. Tuna species migrate across entire ocean basins.

Managing these resources requires international cooperation through organizations like:

• The International Pacific Salmon Fisheries Commission (U.S.-Canada)
• The Inter-American Tropical Tuna Commission (Eastern Pacific)
• The International Commission for the Conservation of Atlantic Tunas
• The North Pacific Fisheries Commission

Energy Resources

The U.S. EEZ contains vast energy resources, both traditional and renewable, that are increasingly important to national energy security and climate goals.

Oil and Gas

The Gulf of Mexico continues to be a major source of domestic energy production, providing about 15% of total U.S. oil production and 5% of natural gas production. Offshore drilling occurs in waters up to 10,000 feet deep, using sophisticated floating platforms and subsea production systems.

The Bureau of Ocean Energy Management within the Interior Department manages leasing and development of these resources on the Outer Continental Shelf. BOEM conducts lease sales where companies bid for the right to explore specific areas. Successful bidders must then conduct environmental studies, develop detailed drilling plans, and obtain multiple permits before beginning operations.

The process is lengthy and expensive. From initial lease to first production can take 7-10 years and cost billions of dollars. Companies must post substantial bonds to ensure proper well abandonment and environmental cleanup.

Major offshore oil and gas areas include:

• Western Gulf of Mexico: Deep-water fields like Perdido and Tahiti
• Central Gulf of Mexico: Established fields in shallower waters
• Atlantic Ocean: Currently under moratorium but with significant resource potential
• Pacific Ocean: Limited activity due to state opposition and environmental concerns
• Arctic Ocean: Vast resources but extremely challenging operating conditions

Offshore Wind

The offshore wind industry is experiencing rapid growth as costs decline and technology improves. The U.S. has excellent wind resources off both the Atlantic and Pacific coasts, as well as in the Great Lakes.

BOEM manages the leasing process for renewable energy projects in federal waters. The agency has held several competitive lease auctions:

Atlantic Coast: Multiple lease areas from Massachusetts to North Carolina, with several projects under construction or in advanced planning Pacific Coast: Floating wind technology needed due to deep waters close to shore Gulf of Mexico: Initial lease sales for both fixed-bottom and floating wind projects

The first major U.S. offshore wind farm, Block Island Wind Farm off Rhode Island, began operating in 2016. Since then, several larger projects have been approved:

• Vineyard Wind off Massachusetts (800 MW)
• South Fork Wind off New York (132 MW)
• Ocean Wind off New Jersey (1,100 MW)

Offshore wind development faces several challenges:

• Visual impacts from shore, particularly in tourism-dependent areas
• Potential conflicts with fishing activities
• Navigation concerns for commercial shipping
• Environmental impacts on marine life, especially birds and marine mammals
• High upfront costs and complex financing requirements

Other Renewable Energy

The EEZ also has potential for other renewable energy technologies:

Wave Energy: Capturing energy from ocean waves using various technologies like oscillating water columns and point absorbers. The Pacific Northwest and Hawaii have particularly good wave resources.

Ocean Thermal Energy Conversion (OTEC): Using temperature differences between surface and deep waters to generate electricity. Most viable in tropical areas like Hawaii and U.S. territories.

Offshore Solar: Floating solar arrays could potentially be deployed in protected waters, though this technology is still experimental.

Current Energy: Harnessing energy from ocean currents like the Gulf Stream. Several pilot projects are exploring this technology off Florida.

Seabed Minerals

The ocean floor within the U.S. EEZ contains potentially valuable deposits of critical minerals needed for modern technology. These resources are becoming increasingly important as the United States seeks to reduce dependence on foreign mineral sources.

Ferromanganese Crusts: Found on seamounts and underwater ridges, these crusts contain:

• Cobalt (essential for electric vehicle batteries)
• Rare earth elements (used in wind turbines and electronics)
• Manganese (steel production)
• Tellurium (solar panels)

Manganese Nodules: Potato-sized lumps found on deep ocean floors, containing:

• Nickel (stainless steel, batteries)
• Copper (electrical wiring, electronics)
• Lithium (batteries)
• Cobalt (batteries, superalloys)

Seafloor Massive Sulfides: Formed by underwater volcanic activity, rich in:

• Gold and silver (electronics, jewelry)
• Copper and zinc (construction, electronics)
• Lead (batteries, construction)

Marine Phosphorites: Sedimentary deposits containing:

• Phosphate (fertilizers)
• Fluorine (chemicals, aluminum production)

The U.S. Geological Survey studies these resources through research cruises and sampling programs. Recent surveys have identified promising areas:

• Ferromanganese crusts in the Arctic Ocean north of Alaska
• Seafloor sulfides in the Escanaba Trough off California
• Phosphorite deposits on the continental shelf

Deep-Sea Mining Challenges

Extracting these minerals presents significant technological and environmental challenges:

Technical Challenges:

• Operating in water depths of 1,000-6,000 meters
• Harsh conditions including high pressure and corrosive seawater
• Remote locations far from shore infrastructure
• Need for specialized mining and processing equipment

Environmental Concerns:

• Potential impacts on deep-sea ecosystems that are poorly understood
• Sediment plumes that could affect marine life over large areas
• Noise impacts on marine mammals and fish
• Risk of equipment loss or accidents in deep water

Economic Considerations:

• High upfront costs for research and development
• Uncertain market demand and pricing for extracted minerals
• Competition from land-based mining and recycling
• Regulatory uncertainty and potential liability issues

Recent executive orders have encouraged research into these resources as part of broader efforts to secure domestic supply chains for critical minerals. However, commercial extraction remains years away and will require careful environmental review.

The Extended Continental Shelf

Beyond the 200-mile EEZ limit, the United States claims rights over the seabed and subsoil of an Extended Continental Shelf (ECS). This represents a potentially massive expansion of U.S. resource jurisdiction.

Legal Basis

Under UNCLOS Article 76, coastal states can claim an ECS if they can demonstrate that the seabed beyond 200 miles is a natural prolongation of their land territory. This requires extensive geological and bathymetric (seafloor depth) data to prove that the continental margin extends beyond the EEZ.

The technical criteria are complex, involving:

• Sediment thickness measurements
• Seafloor depth contours
• Distance from the foot of the continental slope
• Geological evidence of continental crust versus oceanic crust

U.S. ECS Claims

In December 2023, the State Department announced the outer limits of the U.S. ECS in seven regions:

Arctic Ocean: North of Alaska, potentially containing vast oil and gas resources Atlantic Ocean: East of the continental United States Bering Sea: Between Alaska and Russia Pacific Ocean: West of California, Oregon, and Washington Gulf of Mexico: South of Texas and Louisiana Mariana Islands: Around Guam and the Northern Mariana Islands Kingman Reef and Palmyra Atoll: Remote Pacific territories

This delineation adds nearly 288,000 square nautical miles (almost one million square kilometers) to U.S. seabed jurisdiction—an area roughly the size of Alaska.

Rights and Limitations

ECS rights apply only to the seabed and subsoil, not the water above. This means:

The U.S. can:

• Explore and exploit seabed resources like oil, gas, and minerals
• Regulate activities affecting the seabed
• License mining and drilling operations
• Control submarine cables and pipelines on the seabed

The U.S. cannot:

• Control navigation in the water above
• Regulate fishing in the water column
• Prevent overflight by foreign aircraft
• Exercise general law enforcement beyond resource-related matters

Challenges and Opportunities

The ECS potentially contains enormous resource wealth, but also presents challenges:

Opportunities:

• Vast oil and gas deposits, particularly in the Arctic
• Deep-sea mineral resources including rare earth elements
• Strategic advantage in controlling critical resources
• Potential for scientific discoveries in largely unexplored areas

Challenges:

• Extreme technical difficulties of operating in remote, deep-water areas
• Environmental risks in pristine ecosystems
• Potential international disputes over boundary lines
• High costs of exploration and development
• Climate change concerns about new fossil fuel development

International Recognition

The U.S. position is that it can establish its ECS under customary international law without joining UNCLOS. However, this approach has limitations:

UNCLOS parties can submit their ECS claims to the Commission on the Limits of the Continental Shelf (CLCS) for review and recommendations. CLCS approval provides international legal certainty and makes boundary disputes less likely.

As a non-party to UNCLOS, the United States cannot use the CLCS process. This means other nations might be less likely to recognize U.S. ECS claims, particularly where they overlap with areas claimed by UNCLOS parties.

Environmental Protection

The United States has significant responsibilities for protecting marine environments within its maritime zones. This involves controlling pollution, establishing protected areas, and enforcing conservation laws.

Pollution Control

In the Territorial Sea: As an area of full sovereignty, the U.S. has broad powers to regulate and prevent pollution from all sources:

• Land-based runoff from agriculture and urban areas
• Atmospheric deposition of pollutants like mercury and nitrogen
• Vessel discharges including oil, sewage, and ballast water
• Industrial discharges from coastal facilities
• Dredging and construction activities

In the Exclusive Economic Zone: The U.S. has jurisdiction to adopt laws and regulations preventing pollution from:

• Vessels (operational discharges, accidental spills)
• Seabed activities (oil and gas drilling, mining)
• Ocean dumping of waste materials
• Pollution from or through the atmosphere

These national regulations must generally align with international standards to avoid creating barriers to navigation.

Key Environmental Laws

Clean Water Act: The Clean Water Act regulates discharges of pollutants into U.S. waters. The law’s application in maritime zones is complex:

• Full application in internal waters like bays and harbors
• Limited application in territorial seas for certain purposes
• Specific provisions for vessel discharges in the EEZ

Oil Pollution Act of 1990: Passed after the Exxon Valdez spill, OPA 90 established comprehensive requirements for:

• Double-hull tanker construction
• Oil spill response planning
• Unlimited liability for spill cleanup costs
• Natural resource damage assessment and restoration

Marine Plastic Pollution Research and Control Act: Addresses the growing problem of plastic pollution in marine environments through research, prevention, and cleanup efforts.

Marine Protected Areas

The United States maintains an extensive network of Marine Protected Areas providing varying levels of protection:

National Marine Sanctuaries

NOAA’s National Marine Sanctuary System includes 15 sanctuaries and two marine national monuments:

Stellwagen Bank (Massachusetts): Protects feeding grounds for humpback whales and other marine life Monitor (North Carolina): Protects the Civil War ironclad USS Monitor and other shipwrecks Gray’s Reef (Georgia): Conserves one of the largest near-shore hard-bottom reefs Florida Keys: Protects coral reefs and supports sustainable tourism and fishing Flower Garden Banks (Texas/Louisiana): Preserves healthy coral reefs in the Gulf of Mexico Monterey Bay (California): Encompasses diverse habitats from kelp forests to deep-sea canyons Channel Islands (California): Often called “America’s Galapagos” for its biodiversity Greater Farallones (California): Protects seabird colonies and marine mammal populations Cordell Bank (California): Preserves an underwater mountain and its rich marine life Olympic Coast (Washington): Protects temperate rainforest coastline and marine ecosystems Hawaiian Islands Humpback Whale: Protects critical humpback whale habitat American Samoa: Preserves tropical coral reef ecosystems Rose Atoll (American Samoa): Remote marine national monument Marianas Trench (Guam/Northern Mariana Islands): Protects the deepest parts of the ocean Thunder Bay (Michigan): Protects Great Lakes shipwrecks and maritime heritage

Marine National Monuments

Presidential proclamations have established several large marine national monuments:

Papahānaumokuākea (Hawaii): One of the world’s largest marine protected areas, encompassing 583,000 square miles of Pacific Ocean

Northeast Canyons and Seamounts (Atlantic): Protects deep-sea canyons and underwater mountains off New England

Pacific Remote Islands: Protects pristine coral reefs and seabird colonies around remote Pacific atolls

Other Protected Areas

National Parks: Many national parks have significant marine components:

• Acadia (Maine): Rocky coastline and cold-water marine life
• Everglades (Florida): Coastal wetlands and shallow marine waters
• Channel Islands (California): “Galapagos of California”
• Glacier Bay (Alaska): Marine wilderness and whale habitat
• Dry Tortugas (Florida): Coral reefs and historic fortifications

National Wildlife Refuges: The U.S. Fish and Wildlife Service manages numerous coastal and marine refuges:

• Alaska Maritime: Protects seabird colonies throughout Alaska
• Hawaiian Islands: Preserves critical habitat for endangered Hawaiian monk seals
• National Key Deer: Protects endangered deer and coastal habitats in Florida

Conservation Laws

Endangered Species Act: The ESA provides strong protection for threatened and endangered marine species:

• North Atlantic right whales (critically endangered with only about 340 individuals remaining)
• Hawaiian monk seals (endangered with about 1,400 individuals)
• Various sea turtle species
• Certain whale and dolphin populations
• Marine fish species like Atlantic salmon and several Pacific salmon runs

The ESA requires federal agencies to ensure their actions don’t jeopardize listed species or destroy critical habitat. This can significantly affect offshore development projects.

Marine Mammal Protection Act: The MMPA establishes a moratorium on “taking” marine mammals, with limited exceptions for:

• Alaska Native subsistence hunting
• Scientific research permits
• Incidental take during fishing operations (with strict limits)
• Military activities (with mitigation measures)

Climate Change and Ocean Acidification

Climate change poses growing challenges for marine ecosystems:

Ocean Warming: Rising temperatures are causing fish and other marine species to shift their ranges, often moving northward or to deeper waters. This disrupts established fisheries and ecosystem relationships.

Ocean Acidification: As seawater absorbs excess atmospheric CO2, it becomes more acidic. This threatens shell-forming organisms like oysters, clams, and coral reefs that form the base of many marine food webs.

Sea Level Rise: Rising seas threaten coastal habitats like salt marshes and mangroves that serve as nurseries for many marine species.

Extreme Weather: More frequent and intense storms damage coral reefs and other sensitive marine habitats.

National Security and Law Enforcement

U.S. maritime zones are critical for national security, serving as the front line for border protection, drug interdiction, and defense against various threats.

U.S. Coast Guard

The U.S. Coast Guard serves as the nation’s primary maritime law enforcement agency, operating under the Department of Homeland Security in peacetime and transferring to the Navy during wartime.

Core Missions

Search and Rescue: The Coast Guard responds to thousands of distress calls annually, saving approximately 3,000-4,000 lives each year. Operations range from small boat rescues near shore to complex helicopter evacuations hundreds of miles offshore.

Drug Interdiction: Coast Guard cutters and aircraft patrol drug trafficking routes, particularly in the Caribbean and Eastern Pacific. The service typically seizes tens of thousands of pounds of cocaine annually, with estimated street values in the billions of dollars.

Migrant Interdiction: The Coast Guard intercepts vessels carrying undocumented migrants, particularly from Cuba and Haiti. This mission involves both humanitarian rescue operations and law enforcement activities.

Fisheries Enforcement: Enforcing U.S. fishing laws and international agreements to prevent illegal, unreported, and unregulated (IUU) fishing. This includes:

• Inspecting U.S. fishing vessels for compliance with quotas and gear restrictions
• Intercepting foreign vessels operating illegally in U.S. waters
• Enforcing marine mammal protection requirements
• Monitoring compliance with international fishery agreements

Port Security: Protecting 361 commercial ports that handle over $3.4 trillion in economic activity annually. This includes:

• Vessel boarding and inspection programs
• Waterside security patrols
• Port facility security assessments
• Hazardous cargo monitoring

Environmental Protection: Responding to oil spills and other marine pollution incidents. The Coast Guard maintains specialized response teams and equipment for major spill response.

International Cooperation

The Coast Guard enhances its effectiveness through international partnerships:

Shiprider Agreements: Allow law enforcement officials from partner nations to embark on U.S. vessels (and vice versa), enabling operations in foreign EEZs. Current agreements include countries in the Caribbean, Central America, and the Pacific.

International Ice Patrol: The Coast Guard operates the only international ice patrol, tracking icebergs in the North Atlantic shipping lanes and providing warnings to mariners worldwide.

Fisheries Partnerships: Working with other nations to combat IUU fishing, including joint patrols and information sharing on vessel movements.

Recent Operations

Operation Martillo: Multi-national effort targeting drug trafficking organizations in Central America and the Caribbean, involving Coast Guard cutters, aircraft, and boarding teams.

Arctic Operations: Increasing presence in Arctic waters as ice melts and activity increases, including icebreaking operations and law enforcement patrols.

Pacific Counter-Narcotics: Operations against “fast boats” carrying drugs from South America, often involving high-speed chases and helicopter operations.

Other Security Agencies

U.S. Customs and Border Protection Air and Marine Operations: CBP AMO provides border security using aircraft and boats to:

• Detect and track suspicious vessels and aircraft approaching U.S. borders
• Provide backup for Coast Guard operations
• Conduct surveillance operations in remote border areas
• Support other law enforcement agencies with air and maritime assets

U.S. Navy: While primarily focused on national defense and power projection, the Navy also contributes to maritime security through:

• Freedom of Navigation Operations (FONOPS) challenging excessive maritime claims
• Counter-piracy operations in areas like the Horn of Africa
• Maritime security cooperation with allied nations
• Intelligence gathering and surveillance operations

Emerging Threats

Cyber Security: Modern vessels rely heavily on computer systems for navigation, cargo management, and communications. Cyber attacks could potentially disable ships or disrupt port operations.

Unmanned Systems: Drones and autonomous underwater vehicles could be used for surveillance, smuggling, or attacks on maritime infrastructure.

Climate Change Impacts: Rising sea levels and extreme weather events threaten coastal infrastructure and may create new security challenges.

Marine Scientific Research

Marine Scientific Research (MSR) provides the foundation for understanding ocean systems, managing resources sustainably, and maintaining national security.

U.S. Research Policy

The United States has developed specific policies for foreign research in its maritime zones, balancing scientific cooperation with national security and resource protection.

In the Territorial Sea: As an area of full sovereignty, advance consent from the U.S. government is required for any foreign MSR. Requests are processed through the State Department in coordination with relevant agencies.

In the EEZ: The U.S. generally promotes research freedom, consistent with the EEZ’s nature as partially international waters. However, consent is required for research that:

• Relates directly to resource exploration or exploitation
• Involves drilling into the continental shelf
• Uses explosives or introduces harmful substances
• Involves artificial islands, installations, or structures
• Occurs in designated marine protected areas
• Studies marine mammals or endangered species
• Requires taking commercial quantities of marine resources
• Involves physical contact with the continental shelf
• Relates to ocean dumping activities

Research Agencies

NOAA: As the nation’s primary civilian ocean agency, NOAA conducts extensive marine research:

Hydrographic Surveys: NOAA’s Office of Coast Survey produces nautical charts essential for safe navigation and legal baseline determination. Modern surveys use multibeam sonar systems that can map large areas of seafloor in unprecedented detail.

Fisheries Research: NOAA Fisheries operates research vessels and conducts stock assessments for commercially important species. This includes annual bottom trawl surveys, acoustic surveys for schooling fish, and long-term monitoring programs.

Climate Research: NOAA operates a global network of ocean observing systems, including:

• Argo float network measuring temperature and salinity
• Tide gauges monitoring sea level changes
• Coral reef monitoring stations
• Deep-sea moorings tracking ocean currents and temperature

Ocean Exploration: NOAA’s Office of Ocean Exploration and Research uses advanced technologies to explore unmapped areas, often discovering new species and geological features.

U.S. Geological Survey: USGS focuses on geological and geophysical research:

• Mapping seafloor geology using seismic surveys and sampling
• Assessing offshore energy and mineral resources
• Studying submarine landslides and other geological hazards
• Monitoring coastal erosion and sediment transport

National Science Foundation: NSF funds academic research through programs like:

• Ocean Drilling Program exploring Earth’s history through seafloor sediments
• Long-term ecological research at marine sites
• Development of new research technologies and instruments

Navy Research: The U.S. Navy conducts extensive ocean research related to its operational needs:

• Underwater acoustics and sonar technology
• Ocean dynamics affecting submarine operations
• Marine meteorology for aviation and surface operations
• Biological fouling and corrosion affecting naval vessels

Research Infrastructure

Research Vessels: The U.S. operates one of the world’s largest academic research fleets, including:

• NOAA ships like the R/V Okeanos Explorer for deep-sea exploration
• Navy research vessels for specialized military applications
• University-operated ships for academic research
• Coast Guard icebreakers for Arctic and Antarctic research

Underwater Vehicles: Advanced technologies for deep-sea research:

• Human-occupied vehicles like Alvin for direct observation
• Remotely operated vehicles (ROVs) for extended deep-sea work
• Autonomous underwater vehicles (AUVs) for large-area surveys
• Gliders for long-term ocean monitoring

Satellite Systems: Space-based observations provide global ocean monitoring:

• Sea surface temperature measurements
• Ocean color indicating biological productivity
• Sea level measurements with millimeter precision
• Wind and wave observations for weather forecasting

Current Research Priorities

Climate Change: Understanding how warming oceans affect marine ecosystems, sea level rise, and weather patterns.

Ocean Acidification: Studying the impacts of changing ocean chemistry on marine life, particularly shell-forming organisms.

Deep-Sea Exploration: Mapping and exploring the vast unmapped areas of the U.S. EEZ, particularly in deep waters.

Ecosystem-Based Management: Developing approaches that consider entire ecosystems rather than single species or activities.

Marine Biotechnology: Exploring potential applications of marine organisms for medicine, materials science, and other fields.

Who’s in Charge

Managing U.S. maritime zones requires coordination among numerous federal agencies, each with specific expertise and statutory authority.

Lead Agencies

Department of State: State leads U.S. maritime policy and international relations:

• Negotiates maritime boundary treaties with other nations
• Chairs the U.S. Baseline Committee ensuring consistent maritime zone definitions
• Processes requests for foreign marine scientific research
• Represents the U.S. in international maritime organizations
• Handles diplomatic protests over maritime incidents

National Oceanic and Atmospheric Administration: NOAA serves as the primary civilian ocean agency:

• Produces official nautical charts depicting maritime zone boundaries
• Manages U.S. fisheries under the Magnuson-Stevens Act
• Operates the National Marine Sanctuary System
• Conducts ocean research and exploration
• Provides weather and ocean forecasting services
• Assesses natural resource damages from spills and other incidents

Department of the Interior: Interior manages offshore natural resources:

• Bureau of Ocean Energy Management: Leases offshore areas for oil, gas, and renewable energy development
• Bureau of Safety and Environmental Enforcement: Enforces safety and environmental regulations for offshore energy operations
• U.S. Geological Survey: Conducts scientific research on marine geology and resources
• U.S. Fish and Wildlife Service: Manages marine wildlife refuges and protects endangered species
• National Park Service: Manages national parks with marine components

U.S. Coast Guard: USCG provides maritime law enforcement and safety services:

• Enforces U.S. laws in territorial seas and the EEZ
• Conducts search and rescue operations
• Provides aids to navigation like lighthouses and buoys
• Responds to oil spills and other marine pollution incidents
• Inspects vessels for safety and security compliance

Other Key Players

Environmental Protection Agency: EPA develops environmental regulations:

• Sets water quality standards under the Clean Water Act
• Regulates vessel discharges and air emissions
• Oversees cleanup of contaminated marine sites
• Conducts environmental impact assessments

U.S. Army Corps of Engineers: USACE has specific regulatory authority:

• Issues permits for structures in navigable waters
• Regulates dredging and fill activities
• Maintains navigation channels and harbors
• Conducts coastal protection projects

Department of Defense: Military agencies have various maritime responsibilities:

• Navy: Projects power globally and ensures freedom of navigation
• Marine Corps: Conducts amphibious operations
• Air Force: Provides maritime patrol aircraft and satellite surveillance

Coordination Challenges

The multi-agency nature of maritime governance creates coordination challenges:

Overlapping Jurisdictions: Different agencies may have authority over the same area for different purposes, requiring careful coordination to avoid conflicts.

Conflicting Mandates: Economic development agencies may have different priorities than environmental protection agencies, requiring high-level policy coordination.

Resource Constraints: Limited budgets require agencies to prioritize activities and coordinate to avoid duplication.

Technical Complexity: Maritime issues often require expertise from multiple disciplines, making interagency cooperation essential.

Coordination Mechanisms

U.S. Baseline Committee: Chaired by the State Department, this interagency body ensures consistent definitions of maritime zone boundaries.

National Ocean Council: Coordinates ocean policy across the federal government, implementing the National Ocean Policy.

Regional Fishery Management Councils: Bring together federal and state agencies with stakeholders to manage fisheries.

Marine Pollution Response Teams: Coordinate multiple agencies during oil spills and other incidents.

Arctic Council: Coordinates U.S. policy in the Arctic with other Arctic nations.

Maritime Boundary Challenges

Establishing precise maritime boundaries between countries requires extensive negotiation and technical work. The process often takes years or decades and can become politically sensitive when valuable resources are involved.

Legal Principles

International law provides several methods for delimiting maritime boundaries:

Equidistance: Drawing a line where every point is equally distant from the nearest points on each country’s coast. This method works well for simple coastlines but can produce unfair results with complex geography.

Equitable Principles: Considering various factors to produce a fair result, including:

• Length of relevant coastlines
• Geographic configuration
• Presence of islands
• Economic factors
• Historical fishing or navigation patterns

Median Line: For boundaries between opposite coasts, often using the equidistance method modified by relevant circumstances.

U.S.-Canada Maritime Issues

Despite the world’s longest peaceful border, several maritime boundary issues remain between the United States and Canada:

Machias Seal Island and the “Grey Zone”: This small rocky island in the Gulf of Maine is claimed by both countries. The surrounding waters, known as the “Grey Zone,” are jointly managed for lobster fishing but the sovereignty dispute affects other activities. The island’s lighthouse is maintained by Canada, but the U.S. also claims it based on different interpretations of historical treaties.

Beaufort Sea: North of Alaska and the Yukon Territory, the two countries disagree on how to extend their land boundary into the Arctic Ocean. Canada favors extending the 141st meridian (the land boundary) straight north, while the U.S. prefers an equidistance line that would give it more territory. The disputed area covers about 6,250 square nautical miles and potentially contains significant oil and gas resources.

Dixon Entrance: Between Alaska and British Columbia, different interpretations of the 1903 Alaska Boundary Tribunal award have created small disputed areas. The disagreement involves which water bodies were considered internal to Alaska versus international waters.

Strait of Juan de Fuca: Off Washington state and British Columbia, the countries use different methods for calculating equidistant boundaries, resulting in small overlapping claims.

Northwest Passage: Perhaps the most significant disagreement involves Canada’s claim that the waters of the Arctic Archipelago, including the Northwest Passage, are Canadian internal waters. The United States and most other nations view these as international straits where vessels have transit passage rights. As Arctic ice melts and shipping increases, this disagreement could become more prominent.

U.S.-Russia Relations

The 1990 USA/USSR Maritime Boundary Agreement established the maritime boundary between the two countries in the Bering Sea, Chukchi Sea, and Arctic Ocean. This agreement resolved a complex situation arising from different interpretations of the 1867 Alaska Purchase.

The original Alaska Purchase treaty described the boundary using coordinates and geographic features, but maps of the era were imprecise. Different map projections and surveying methods led to conflicting interpretations, creating an overlapping claim area of about 15,000 square nautical miles.

The 1990 agreement established the “Baker-Shevardnadze line” (named after the negotiators) that generally favored the Soviet position. While the U.S. Senate ratified the agreement in 1991, and both countries have applied it in practice, the Russian Duma has never ratified it. This creates legal uncertainty, though both sides continue to respect the boundary in practice.

Russian concerns about ratification include:

• Perceptions that Russia gave up too much valuable fishing area
• Domestic political sensitivity about any territorial concessions
• Changes in fishing patterns since 1990 that may favor different boundary arrangements

U.S.-Mexico Boundaries

The United States and Mexico have successfully negotiated maritime boundaries in both the Gulf of Mexico and the Pacific Ocean:

Gulf of Mexico: A 1978 treaty established the boundary from the mouth of the Rio Grande to the edge of the continental shelf. The boundary generally follows an equidistance line with some adjustments for small geographic features.

Pacific Ocean: A 1970 treaty established the boundary off California, extending 12 nautical miles from the land boundary at the Pacific coast.

Both treaties have worked well and serve as models for successful boundary negotiations.

Complex Boundary Situations

Some boundary situations involve multiple countries or special circumstances:

Bering Sea “Donut Hole”: An area of high seas surrounded by U.S. and Russian EEZs became the center of international fishing disputes in the 1980s and 1990s. The “donut hole” was heavily fished by vessels from various countries, leading to stock depletion and conflicts with adjacent coastal state fisheries. International agreements eventually brought this area under management controls.

Caribbean Boundaries: The Caribbean involves numerous countries with complex overlapping claims. The U.S. has maritime boundaries with several Caribbean nations, though some technical issues remain.

Pacific Island Boundaries: U.S. territories in the Pacific create complex boundary situations with neighboring island nations, some involving very small land features that can generate large maritime zones.

Resolution Mechanisms

When countries cannot negotiate boundary agreements, several resolution mechanisms are available:

International Court of Justice: Can decide boundary disputes if both parties agree to its jurisdiction.

International Tribunal for the Law of the Sea: Established by UNCLOS to resolve maritime disputes, though the U.S. cannot use this mechanism as a non-party to the treaty.

Arbitration: Countries can agree to binding arbitration using various arbitration rules.

Joint Development: Instead of resolving boundary disputes, countries sometimes agree to jointly develop resources in disputed areas.

The resolution process typically involves:

• Technical working groups of hydrographers, geologists, and legal experts
• Political negotiations between foreign ministries
• Public consultation in democratic countries
• Legislative ratification of any agreements

Successful boundary agreements provide legal certainty that encourages investment in offshore development and reduces the risk of international incidents. However, the process is often lengthy and complex, requiring significant political will from all parties involved.

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