The late "Crocodile Hunter" and animal activist would have turned 58 on Saturday

The Irwin family is remembering Steve Irwin on what would have been his 58th birthday.

On Saturday, the animal activist’s daughter Bindi Irwin shared a sweet photo of herself and her late father as she penned an emotional tribute in his honor.

“Dad, Today is your birthday,” Bindi, 21, captioned the post, which included a photo of her dad holding a porcupine and wearing an Australia Zoo shirt. “I had an extra strong cup of tea just how you liked it. I hugged Mum for you and told her how much we love her. Robert and I went on a hike through the mountains you cherished. I watched one of your documentaries with Chandler and shared stories about you. I walked through your office in the zoo and smiled at our old family photographs.”

“Today and every day I miss you and love you beyond description,” she concluded the post. “You’re always with me. ❤️”

Steve’s wife Terri Irwin also remembered her husband on Saturday, calling him her “best friend” in a Twitter post that included four photos of the late “Crocodile Hunter.”

“Today would’ve been Steve’s 58th birthday,” she wrote. “While my heart aches missing him every day, I’m determined to celebrate what he loved the most. He was happiest spending time @AustraliaZoo w/ @BindiIrwin & @RobertIrwin. He was my best friend, best dad, & built the best Zoo. I love you.”

“Family Always ❤️,” Steve’s son and Bindi’s brother Robert Irwin, 16, captioned his own post, which featured a throwback family shot.

Bindi’s fiancé Chandler Powell — who popped the question last summer, on Bindi’s 21st birthday — also paid tribute to Steve on Saturday.

“Thank you for inspiring me and the whole world to love all wildlife,” he wrote in an Instagram post. “You would be so proud of Bindi, Terri and Robert carrying on the amazing work you started. We will all make sure your message lives on for generations❤️?.”

The beloved wildlife expert was working on the documentary series Ocean’s Deadliest when he was attacked by a stingray off the coast of northern Australia and died on Sept. 4, 2006. He was 44.

Every year on Nov. 15, Steve’s family celebrates his legacy on Steve Irwin Day, the annual international event honoring the life and legacy of the beloved Animal Planet star.

“Dad was my hero and the greatest Wildlife Warrior,” Bindi told PEOPLE on last year’s Steve Irwin Day. “It’s a blessing to continue his work with my amazing family. We hope to make him proud every day. We are celebrating with lots of khaki and animals! Khaki’s not just a color, it’s an attitude!”

The Irwin family continues to run Australia Zoo together, recently taking in animals during the bushfires that ravaged the country for months.