Aquarium plans for the former Wildwalk site at Explore-At-Bristol on the Harbourside are still on target, says Newquay firm Blue Reef.

Work did start on the £4-million project last July, but the scheme is now set to get going "in earnest" in the first half of this month and open before the end of the summer, says Blue Reef.

Spokesperson Drew Cunliffe said: "Everything is progressing according to plan.

"Electricians have been working over the Christmas period on site and work is now taking place on strengthening foundations in preparation for the arrival of the large display tanks.

"Work did start in July and August. However, this was first stage activity, which involved clearing the site. Actual construction work was always planned to start in January."

The project will showcase native, tropical and freshwater creatures from around the world in naturally-themed habitats.

Visitors will embark on what Blue Reef calls "a fascinating journey from the British coast through warmer waters to exotic tropical seas".

The company, which also has aquariums in Portsmouth, Tynemouth, Newquay and Hastings, will also operate an Imax theatre alongside the Bristol attraction.

The site, which opened in 2000, was home to Wildwalk and a giant 68ft by 48ft Imax screen. But both attractions closed in April 2007 after Explore-At-Bristol managers said they were no longer financially viable.

The Cornish company – which was bought by Spanish firm Aspro in April last year – was selected for the project after a year's search by Explore-At-Bristol, its partners the South West of England Regional Development Agency and Bristol City Council to find a replacement for Wildwalk.

Nikki Smith, of Blue Reef, said: "It will be a world-class aquarium in a fantastic location."

At the time the company's name was announced to the Bristol public nine months ago, the project was expected to create a total of 35 new jobs.

But there were worries about the looming credit crunch even then. John Hallett, managing director of Destination Bristol, was challenged about whether the aquarium would draw enough visitors.

Mr Hallett said: "The reality is that Bristol's tourism offer is tremendously strong and getting better every year. We are confident about its prospects."

"There is also a real paradox in the visitor economy. When consumer spending is squeezed, the result is that people take more day trips and fewer longer holidays.

"So city visitor attractions can do well in these circumstances if they are providing great experiences and real value for money."