Have you been to Newsela? They have "real" articles (sources like AP or Scientific American) that can are available in a variety of grade levels & lexile levels. The site requires a username, but it's free and WELL worth it!
Just type "sharks" into the search box and plenty of articles will pop up. Here's one.
I think this would be tons of fun for a multi-age home school or multi-level class... you're third grader and sixth grader could read the same article!
SHARK ADVOCATES
Sharks4Kids advocates for sharks through education. They have teacher resources including vocabulary, non-fiction compare & contrast activities for multiple grades, and short videos.
GEOGRAPHY
Multiple Shark Trackers for different parts of the globe
POETRY/LITERATURE
Write a Cinquain Poemusing this template!
{I like cinquain poems because they emphasize parts of speech.}
Put your final copy poem in a shark outline. Write your cinquain twice if you want it to go around the shark!
SCIENCE
Here's a "Finned, Floating, & Fabulous" experiment that explains why sharks float.