New England’s fishing industry will be substantially scaled back under new federal rules announced Friday. The regulations, which reduce the number of days fishers can work, close key fishing areas, and limit the size of fish that may be caught, were met with dismay by the industry. After more than 400 years of large-scale fishing, the region’s fish stocks bottomed out in 1994, prompting the government to close more than 5,000 square nautical miles of prime fishing spots and reduce the number of days at sea to 50 percent of pre-1994 levels for all vessels, among other regulations. Even fishers agree that some of those measures were necessary to save fish stocks, but now, they argue, species are recovering and regulations should be relaxed, instead of tightened. Conservationists disagree and support the stricter restrictions, pointing out that only one of 18 ground-fish species has fully recovered from overfishing. Overall, the North Atlantic has just one-sixth the number of fish it had a century ago, while fishing is eight times more intensive.