Mystic ― Over the last 50 years, Mystic Aquarium has taken 5,000 calls about stranded or injured wild marine mammals and sea turtles.

An estimated 25,000 people have participated in its citizen science programs and cleanups that removed 54,000 pounds of trash from the environment, its staff has published 308 scientific papers and reached 3.5 million children through its education programs.

“People do not know what we do: what it takes to run an aquarium, what it takes to feed our animals, what exactly our vets and scientists are doing — they’re not sitting around eating bon-bons,” said Susette Tibus, the aquarium’s president and chief executive officer, as she strode quickly and purposefully through the aquarium campus on a rainy September morning.

On Oct. 6, Mystic Aquarium celebrated its 50th birthday, and though much has changed since its 1973 opening, its original progressive ideas about how to care for animals and its dedication to education, conservation, first-rate veterinary care and cutting-edge research have remained the same.

“We are proud of our history and excited for the hope and promise of the future,” she said.

For Tibus, who was appointed in April, the work to secure the future of the aquarium has already begun with new and refurbished exhibits.

The aquarium recently renovated its penguin exhibit and opened “Dino Seas,” an interactive exhibit which focuses on prehistoric sea creatures and includes animatronic dinosaurs, an indoor playscape, two 4D theaters and educational video games.

Bryan Schultz, vice president of exhibits, said the project was made possible by a lot of sweat equity and the generosity of donors, one of whom donated all the sea creatures.

A new California sea lion show features a handful of the aquarium’s 15 sea lions throwing a birthday party for guests twice a day on weekdays and three times a day on weekends.

Through entertaining party games, music and a message of conservation, the new show contributes to the organization’s mission by teaching about recycling and caring for the animals’ ocean home.

By teaching children to be environmentally conscious, Tibus said she believes there will be a point where conservation comes naturally.

In 1973, visitors did not see some of the staples that visitors to the state’s largest tourist draw expect to see today. Beluga whales arrived in 1975. Seal Island opened in 1977 and penguins first arrived in 1989. Titanic discoverer Bob Ballard’s Institute for Exploration opened in 1999. For years, the aquarium had a dolphin show but that was later phased out.

In fact, 50 years ago, the Mystic Marinelife Aquarium consisted of just one building housing the Marine Theater and an assortment of fish and invertebrate exhibits. An outdoor lake was inaccessible to the public but provided nice views from several areas of the aquarium.

Today, the small aquarium and its mission have expanded not just in size but also in scope, with a rescue program, state of the art animal care, global research and even a preschool.

The aquarium does all this on a $30 million annual operating budget, a heavy lift for an organization which receives 75% of its revenue from memberships and ticket sales.

Koray Gurz, chief operating officer, said that the $30 million does not include capital expenditures to keep up with repairing and replacing 50-year-old infrastructure such as chillers that keep water in the exhibits at precise temperatures.

Tibus said the aquarium is beginning work on its strategic plan that will govern how the aquarium moves forward over the next several years, but she is focusing on the challenges that lay before her and the organization.

“First, you have to build trust, and that starts with leadership,” she said.

She said that she is focusing on making cultural changes in the organization, and learning “the good, the bad, and the ugly,” from each department head before beginning to plan.

She noted that each department has its own concerns and needs, and she made it a point to learn what all of them were.

“Learning is a part of growth,” she said.

Budgets will determine what projects the aquarium undertakes, but Tibus, who joined the aquarium’s board of directors in 2009, has a few broad goals.

She pointed through the window of her office at the seal rescue clinic and said one of her goals is to expand and improve the clinic’s facilities. She would also like to grow the penguin exhibit and address the aging infrastructure. She added the aquarium is working to secure funding from donors and the state to create a new river otter exhibit.

Expansion and improvement have a price though, so Tibus also wants to expand the organization’s donor base. She said the aquarium has approximately 45,000 donors, but that she would like to expand the base into Fairfield County and New York as 55% of visitors to the aquarium each year come from outside Connecticut.

One cost-free goal she has is to highlight what visitors don’t see: the work done by the staff and volunteers to care for the animals and operate the massive organization with so many moving parts.

“I think the difference between me and a lot of CEO’s is that I don’t fly solo,” she said emphasizing that the work of running the aquarium and overseeing all of the programs take a team effort.

The aquarium is wrapping up its 50-day celebration which will end Oct. 15, but visitors still have time to participate. A schedule of events is available on the website at www.Mysticaquarium.org.

On Saturday, the Greater Mystic Chamber of Commerce will host a day-long celebration of the aquarium’s 50th birthday. Tibus will lead a 1 p.m. ceremony at Mystic River Park which will be followed by a chili cook-off, live music and a fireworks show at 7:30 p.m.