Oil and natural gas activity off the British coast should wax and wane in the short-term after one of the industry's worst years, Wood Mackenzie finds.

Lower crude oil prices and an uncertain economic future in the wake of last year's vote to leave the European Union put the British offshore oil and gas industry in "full survival mode," according to a report from Wood Mackenzie.

Fiona Legate, a senior analyst with the group, said in a statement that capital investments offshore last year declined 20 percent to just over $10 billion, a figure reflected in a lower appetite for new assessments offshore. That, however, masks otherwise upbeat performances.

"Exploration and appraisal drilling hit a 50-year low in 2016, but despite this volumes discovered were the highest since 2008," she said in the report.

A report early last year from the British government said the industry was showing resilience in the face of lower crude oil prices, which are about half what they were at their recent peaks above $100 per barrel in 2014. After 2021, the government said, both oil and gas production are assumed to drift lower at a rate of about 5 percent per year.

The British government assumed a worst-case oil production estimate of around 220 million barrels to hold through the end of the decade. Production in 2015 was around 330 million barrels. Gas production, meanwhile, declines steadily through the end of the decade, though the British mainland could see some growth from the fledgling shale industry.

Even though some areas are running dry, BP said the North Sea remained a central component of its portfolio. The company plans to drill up to five exploration wells over the next 18 months and 50 development wells over the next three to four years

Offshore, Wood Mackenzie said more than a dozen new oil and natural gas fields are expected to enter into production this year, though gains will be short-term ones.

New developments will be scarce, but "by 2020, 30 percent of production will come from fields that aren't onstream yet," Legate said.