When a flotilla of 200 pint-sized Canadian fishing boats blockaded a mammoth American passenger ferry in Prince Rupert, British Columbia, this past weekend, it was the latest and biggest skirmish between North America's generally amiable giants.
The Canadians prevented the ferry from leaving port to protest what they charge is American pilfering of up to $5 million in salmon so far this year.
In the context of the $1 billion in goods and services that is traded across the US-Canadian border every day, this dispute is relatively small fry. But as the two nations have become more economically intertwined - especially since the North American Free Trade Agreement was signed in 1993 - a growing number of disputes have been nettling relations.
On trade issues, "the US-Canada relationship ... has turned out to be a mixed bag," says Steven Globerman, a trade expert. "With NAFTA, there are mechanisms in place to resolve disputes," he says. But "the number of disputes is increasing, because there are more commercial interests who see themselves being adversely affected."
The cross-border flash points include:
* The US timber industry, forced to reduce logging on public lands to comply with environmental laws, claims Canadians are flooding the market with trees, threatening US jobs.
* Canadians are fuming over US efforts to stymie a requirement that American magazines produce the majority of the content of their Canadian editions north of the border.
* US citizens heading north grumble about Canada's policy that treats drunk driving as a felony - even if a conviction came years earlier - and forces those with prior arrests to post a bond before they enter the country.
The biggest controversy is over harvest levels for Pacific salmon. Mariners from both nations fish in common coastal waters, but Americans have touched off a row by taking what Canadians believe is more than their fair share. Further irking Canadians is that no agreement has been reached that clearly defines fishing quotas. Talks on the issue have been only sporadic.
"The level of frustration and rhetoric is rising over the salmon dispute," says Deborah Daoust, a spokeswoman for the Canadian Consulate General's Office in Seattle. "While I don't see nation-to-nation relations becoming any more contentious, concern over the impact of American corporations is increasing."
Canada claims Alaskan fishermen have caught about 350,000 Canada-bound sockeye salmon so far this season - an increase of 300 percent from the average of previous years.
But the US says Alaskan fishermen always catch some sockeye along with pink salmon - which Americans are entitled to catch - because the species run together. The US has yet to respond to a diplomatic note that Canada fired off this weekend.
Despite searing salmon rhetoric, there is much talk of erasing the economic border between the countries - including dropping the current tariffs on roughly one-quarter of the goods and services traded - within 20 years.
It would help both nations' trade balance sheets. But some Canadians bristle at the cultural implications of this "bulldoze the border" attitude; they don't want to import US social problems too.
"There still are strong elements of fear on the Canadian side as to what seamless free trade with the US means to its culture and way of life," says Jane Breederland of the International Center for Canadian-American Free Trade.