While illegal crossings are impossible to count, experts look to Border Patrol apprehensions as the best indicator of migrant traffic.
Get-tough immigration policies are certainly having an impact on the number of people crossing into the United States illegally.
But for California’s vast agriculture business, the crackdowns may be bringing costly consequences.
Some of the state's farmers grow crops that need to be picked by hand. From melons in the Imperial Valley to grapes and berries up the central coast and nut products to the very north, these delicate crops require the hands of about 500,000 workers.
For generations, many of those workers have been illegal Mexican immigrants, who historically have crossed into the state in early spring before returning home in the fall. They have come illegally because of laws that limit their legal numbers.
Now this unwritten agreement between employers and employees is in trouble. Over the past few years, border enforcement has interfered with the movement of the illegal labor force. A recent study by the Pew Hispanic Center cites the extent that the illegal immigrant workforce has declined in recent years.
Whereas one million crossed over in 2005, only 286,000 dared to do so in 2011. While not all immigrants come to work in the fields, that still represents a huge drop in the labor pool for these agricultural jobs.
And California is the most dependent state on seasonal workers, according to the U.S. Department of Agriculture.
About $3 billion of production of California's $40 billion agriculture industry requires hand picking, three times as much as the next state, Florida.
Yet, with so few people able to come into the state, even if all 286,000 illegals dedicated themselves to crop harvests, we would still have only about half the required labor. Even that number is optimistic, because some adults will not work in agriculture at all. Others are young children.
How this plays out remains to be seen. We know that last year, many farmers in the state were unable to harvest all their crops because of labor shortages.
That translates into fewer sales for farmers, and by extension less revenue for the state. If the most recent illegal crossing numbers are any indication, this year is likely to be worse.
So there you have it. Our borders may be more secure, but we may be paying for that security in lost farm income and higher consumer prices at the supermarket.
Larry Gerston teaches political science at San Jose State University and is the political analyst at NBC Bay Area.