E.g., 04/19/2024
E.g., 04/19/2024
The Merits and Limitations of Spain's High-Tech Border Control

The Merits and Limitations of Spain's High-Tech Border Control

For more than a decade, Spanish authorities have been faced with the challenge of controlling large-scale unauthorized migration along extensive coastlines. An important part of the response has been the development of a state-of-the-art surveillance system.

The technical aspects of the system have attracted international attention and praise from the European Union. Spain's efficacy in migration control, however, is entangled with smugglers' responses and the authorities' capacity to cope with large numbers of migrants once they have been apprehended.

There are many parallels between the U.S.-Mexico border and Spain's border with the countries south of the Mediterranean Sea. Both represent sharp differentials in income and standards of living, and both receive substantial migration pressure from developing countries.

Migration pressure exists when the number of people wishing to migrate exceeds the capacity or willingness of the destination country to open its doors to immigrants. The desire to emigrate from a specific country often results from a mix of economic, social, and political factors.

One crucial difference between the U.S.-Mexico border and Spain's southern border is that Europe's southern borders are, by and large, maritime borders (although the Spanish enclaves of Ceuta and Melilla have land borders with Morocco). A land border can — at least in theory — be controlled by erecting physical barriers to keep people out, which is not possible with maritime borders.

Therefore, control of a maritime border is largely confined to detecting and apprehending those who enter. Spanish authorities have developed the so-called Integrated System of External Vigilance (SIVE) for performing these two tasks as efficiently as possible.

Migration Pressure on Spain's Maritime Borders

The two large sections of Spain's maritime borders that face Africa have experienced an increase in migration pressure: the coast of Andalucia on the Spanish mainland, and the southern and eastern coasts of the Canary Islands (see map).


The southernmost tip of the Andalucian coastline is the Spanish side of the Strait of Gibraltar. This strait, which separates Europe from Africa by only 12 kilometers (8 miles), has come to epitomize the disparity between the two continents.

Unauthorized migration across the Strait of Gibraltar took place as early as the 1960s, when thousands of Moroccans went to France as labor migrants. Spain did not require them to obtain a visa, making it easier to cross by boat and make one's way to France over land with minimal paperwork.

In 1991, Spain imposed a visa requirement for North Africans, and unauthorized entry became important as a means of evading controls.

Initially, Moroccans dominated the subsequent flow of unauthorized boat migrants. Since the late 1990s, however, an increasing proportion have been sub-Saharan Africans transiting through Morocco. The total number of unauthorized migrants intercepted along the coasts of mainland Spain peaked at 17,000 in 2000 according to Spanish government statistics.

Since 2002, unauthorized boat migrants arriving on the Canary Islands have outnumbered those who reach the coasts of mainland Spain. The island of Fuerteventura, which is closest to the African mainland, lies 120 km (75 miles) off the coast, and the trip takes about 20 hours by boat if the weather is good.

Until 2005, the vast majority of boat migrants arriving on the Canary Islands departed from the closest sections of the mainland coast, on either side of the border between Western Sahara and Morocco. Western Sahara is currently occupied by Morocco.

In 2006, there was a significant shift, with more and more migrants arriving from points further south, primarily Mauritania and Senegal. The total number of arrivals on the Canary Islands reached new heights as a result of this development. After 9,000 to 10,000 interceptions per year from 2002 to 2004, the number dropped to less than 5,000 in 2005, and then jumped to 31,000 in 2006. The Spanish authorities compile and report these figures.

Per capita income in Spain, adjusted for the cost of living, is approximately six times the capita income in Morocco. This is considerably more than the 4:1 ratio between the United States and Mexico.

Although Spain and Senegal are not neighboring countries, thousands of migrants have left Senegal and traveled directly to the Canary Islands by boat in recent years. In this case, the difference in income per capita is a staggering 15:1.

The Integrated System of External Vigilance (SIVE)

While the routes have shifted and the preferred type of boat has changed, unauthorized migration across Spain's maritime borders continues to be dominated by relatively small vessels that rarely carry more than 100 people. Without extensive surveillance, therefore, these boats can easily arrive undetected.

In 1999, the Spanish government approved a plan for intensified surveillance of the Strait of Gibraltar, where the majority of unauthorized migrants were arriving. The plan centered on the implementation of the Integrated System of External Vigilance (SIVE), and had a budget of about 150 million euros for the period 1999 to 2004. This amounted to about 1,800 euros for each migrant that was eventually intercepted during the five-year period in question.

The government justified the expenditure in part with reference to Spain's obligations vis-à-vis Europe. The elimination of internal borders within much of the European Union meant that control of the Spanish borders was important to countries much further north.

Humanitarian nongovernmental organizations (NGOs), the Catholic Church, and many local politicians in the affected areas vehemently opposed SIVE. They argued that it was a repressive measure and that the money would be better spent on development assistance to the countries of origin.

The Spanish government responded that SIVE was not only important because of relations with other European countries, but that the system also had an important humanitarian element. Namely, SIVE provided capacity to rescue migrants in distress and to help fight against drug smuggling.

How SIVE Works

The key principles in the design of SIVE are early detection and central command. It is the investment in technology guided by these two principles that sets SIVE apart from mere patrolling. The Guardia Civil, a joint military and civilian police force, operates SIVE.

The system's functions can be summarized in the following steps:

  1. A small boat with migrants on board approaches the coast.
  2. A system of fixed and mobile sensors (radars, infrared cameras, and video cameras) detects the vessel 10 to 25 kilometers from the shore.
  3. The control center is alerted and can follow the vessel by remote control of the sensors. At a distance of approximately 5 kilometers from the coast, it is possible to estimate the number of people on board.
  4. The vessel's course and time of arrival are estimated.
  5. One or more interception units (boats, helicopters, and cars) are deployed in order to intercept the vessel close to the shore.
  6. The passengers are apprehended and brought to a reception center.

When the system works as intended, the Guardia Civil can start preparing for the interception several hours before the vessel reaches the shore.

Shifts in Migration Routes after the Expansion of SIVE

First developed along the Strait of Gibraltar, SIVE was subsequently extended to the east and to the west. As of 2007, it covers the entire Andalucian coast.

The government has also installed the system on the Canary Islands. In 2002, three fixed detection stations were installed on Fuerteventura. The system has been extended to the islands of Lanzarote and Gran Canaria.

This expansion has led to geographical shifts in human smuggling routes. First and foremost is the shift from the Andalucian coast to the Canary Islands. In the two years following the initiation of SIVE on the mainland, the Canary Islands' proportion of total interceptions rose from 12 percent to 59 percent, according to Spanish government statistics.

Along the coast of the Spanish mainland, a progressively smaller proportion of migrant boats have crossed the narrow Strait of Gibraltar, where SIVE was first installed and has had the greatest impact. Instead, smugglers have turned to crossing the westernmost part of the Mediterranean Sea, known as the Sea of Alborán.

Similarly, on the Canary Islands, boat migrant arrivals have spread toward areas with less surveillance. In the summer of 2001, Lanzarote, which had previously been only marginally affected, was suddenly receiving a third of all boat migrants. This was interpreted as a response to the installation of SIVE on Fuerteventura.

Even on the island of Fuerteventura itself, arrivals have shifted away from the south, where the SIVE installations were first located, toward the area around the capital, Puerto del Rosario.

The relocation of smuggling routes not only means the problem of undetected arrivals persists, it also means migrants may take longer and more dangerous routes. This has been the case along the U.S.-Mexico border. As documented by political scientist Wayne Cornelius, tightened security along the most accessible sections of the border has pushed migrants into the deserts and mountains, and led to higher fatality figures.

While it is clear that boat migrants headed for Spain have taken progressively longer routes, it is not altogether certain that the routes are more dangerous. The shortest route, across the Strait of the Gibraltar, is, in fact, particularly dangerous because of strong currents.

Even if the routes taken are not more dangerous, however, diversion of the routes can mean that migrants arrive in areas without an established humanitarian infrastructure to receive them. When migration shifted away from the Strait of Gibraltar, local authorities and NGOs in the area had acquired substantial experience in receiving and providing treatment for the boat migrants.

One risk that follows from the longer routes is that boats can drift unnoticed for days and weeks if the engines fail. In several recent cases, migrants have died of thirst and hunger at sea. In one case, a boat headed for the Canary Islands that set out from the Cape Verde Islands, off the coast of Senegal, was found off the coast of Barbados after drifting across the Atlantic.

The Guardia Civil was not developed for rescue operations, and has not been prepared for emergencies with migrant boats at sea. Nevertheless, it seems clear that SIVE has also saved lives when boats in distress have been detected and assisted.

While the extent of migrant fatalities along the Spanish coasts remains unknown, they add up to hundreds every year, making deaths among prospective migrants one of Europe's most pressing humanitarian issues. Therefore, the success of border control strategies must be measured in terms of effective prevention of illegal entry as well as with reference to the number of migrant deaths.

Smugglers' Response to SIVE

The development of SIVE has not only led smugglers to adopt new routes, but also has resulted in technical and organizational changes on the part of the smugglers.

One such change is the use of larger and faster boats. Wooden fishing boats have increasingly been replaced by inflatable boats with outboard motors that travel at high speed and carry up to 70 passengers. Smugglers have also evaded the Guardia Civil by arriving in groups of several boats and fanning out when they approach the coast.

Most importantly, smugglers have accepted the increased likelihood of being detected and apprehended. When it is understood that the boat will be intercepted, different incentives come into play for migrants and smugglers.

The migrants being smuggled are increasingly sub-Saharan Africans who are more difficult for Spanish authorities to return to their countries of origin than is the case with Moroccan migrants. The sub-Saharan Africans thus have less to lose by being apprehended.

For the smugglers, sending migrants off on their own means avoiding the risk of arrest. Knowing that the boat will be lost is an incentive to build it cheaply, and not having to carry fuel for the return trip allows space for even more migrants. Inexperienced migrants at the helm, poorly constructed or dilapidated boats, crowding on board, and insufficient fuel are all factors that increase the risks of the journey.

Why SIVE Does Not Stop Unauthorized Immigration

As noted, SIVE was developed to detect and apprehend unauthorized boat migrants as efficiently as possible. Even if the system excels at these tasks, it is merely one link in the chain that constitutes a migration control strategy.

After being apprehended, migrants must be processed on a case-by-case basis. If they seek asylum, their claims must be evaluated. If the outcome is negative, or if there was no asylum claim in the first place, Spanish authorities must ascertain the migrants' nationality in order to have him or her returned to the country of origin.

While Morocco allows Spain to return Moroccans who have crossed without authorization, Spanish efforts to return sub-Saharan African transit migrants to Morocco have largely been unsuccessful. In recent years, Spain has made great efforts to make sub-Saharan African countries sign readmission agreements that facilitate such returns.

Under Spanish law, migrants can be detained for up to 40 days in reception centers. If they cannot be sent home within this period, they are released. These migrants are issued an expulsion order that bars them from working, but many remain in Spain or other European countries, and some have eventually obtained residence permits due to regularization (see related article).

While SIVE has been a progressively stronger link in the chain of European migration control, case-by-case processing and the inability to return many of those expelled are links that have weakened the chain.

Yet, Spain cannot abandon case-by-case processing because failing to evaluate individual asylum claims of intercepted migrants would mean failing to fulfill humanitarian obligations. The inability to return those deemed ineligible for protection means Spain (and by extension, Europe) must accommodate large numbers of migrants that are admitted on the basis of democratically founded policies. Consequently, the merits of SIVE become largely irrelevant.

The only way in which SIVE can reduce the number of boat migrants headed to Spain is through deterrence. This has probably happened to some extent with Moroccans. They know, through the media and word of mouth, that their chances of apprehension are very high, and that prompt return to Morocco is likely to follow.

This is still far from being the case with sub-Saharan Africans. The fluctuations and shifts in routes from West Africa to the Canary Islands seem to have more to do with control measures along the African coasts than with the prospects of being apprehended and returned from Spain.

This article is based on an article that appeared in the summer 2007 edition of the International Migration Review.


Carling, J. 2007. "Migration control and migrant fatalities at the Spanish-African borders." International Migration Review 41 (2):316–343.

Carling, J. 2007. "Unauthorized migration from Africa to Spain." International Migration (in press).

Cornelius, W. 2001. "Death at the border: Efficacy and unintended consequences of U.S. immigration control policy." Population and Development Review. 27(4):661-685.