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.
Blue whale
However, blue whales 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. 
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
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Blue whale [SEP] Migration
The mechanism behind modern whale migration is debated. Migration may function to reduce parasitism, pathogens, and competition, provide greater access to prey in the spring and summer, reduce calf predation from orcas, and optimize thermoregulation for growth in the winter. For many baleen whales, such as humpback and grey whales, a general migration pattern can be defined as to-and-fro migration between feeding grounds at higher latitudes and breeding habitats at lower latitudes on an annual basis. However, blue whales 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.