can we eat them?
Yes
Krill
Krill is a rich source of protein and omega-3 fatty acids which are under development in the early 21st century as human food, dietary supplements as oil capsules, livestock food, and pet food. 
how long does it take for a blue whale to give birth Gestation lasts 10–11 months. where are these type of whales mostly found? Monterey Bay, San Diego, Baja California Sur, Mexico; Gulf of St. Lawrence to name some. where is this bay located? On the coast of the U.S. state of California. can you name some rivers or lakes found here? Sacramento River, San Joaquin River, Pit River, Feather River and Tuolumne River. are there any protected areas here? Yes, Soquel Canyon State Marine Conservation Area, Portuguese Ledge State Marine Conservation Area, Pacific Grove Marine Gardens State Marine Conservation Area, etc. how long can the former whale live for? 73 years do these whales migrate? They are not as specific in their movement patterns, and there is substantial evidence of alternative strategies, such as year-round residency, partial or differential migration, and anomalous habits such as feeding on breeding grounds. what is the diet like of these whales? Its diet consists almost exclusively of euphausiids (krill) except off Sri Lanka. what is krill? Small crustaceans of the order Euphausiacea. how does plastic effect them? Preliminary research indicates krill can digest microplastics under in diameter, breaking them down and excreting them back into the environment in smaller form.
wiki:11729824
Krill [SEP] Human consumption
Although the total biomass of Antarctic krill may be as abundant as 400 million tonnes, the human impact on this keystone species is growing, with a 39% increase in total fishing yield to 294,000 tonnes over 2010–2014. Major countries involved in krill harvesting are Norway (56% of total catch in 2014), the Republic of Korea (19%), and China (18%). Krill is a rich source of protein and omega-3 fatty acids which are under development in the early 21st century as human food, dietary supplements as oil capsules, livestock food, and pet food. Krill tastes salty with a somewhat stronger fish flavor than shrimp.