Majestic gray whales have already begun their annual 10, 000-mile round-trip journey, traveling from their feeding grounds in the Bering Sea to the tropical lagoons of Baja, Mexico, to play, rest, breed and give birth. The natural phenomenon signals the start of the popular whale-watching season around San Diego’s coastline. These gentle giants, which can reach lengths of 45 feet, pass in close proximity to the coast of San Diego every year on the longest mammal migration in the world.  “We usually see them on their way down to Baja around mid- to late December,” said Staci Shaut, the whale-watching lead at Scripps Institution of Oceanography’s Birch Aquarium.  “Then we see them passing on their way back north in mid- to late March.” “They are numbering around 20,000 animals and that is a safe estimate,” said Wayne Perryman, a biologist at the National Oceanographic and Atmospheric Administration.   The primarily Arctic whales spend from June to October feeding in and around the Bering Sea in preparation for the trip.  “The whales are able to consume around 2,400 pounds of food a day in the nutrient-rich waters of the Arctic,” Shaut said. The huge caloric intake is converted into fat or blubber stores.  Most whales are estimated to put on 6 to 12 inches of blubber, which they rely on during their migratory journey, Shaut said. Gray whales belong to the baleen family, yet their feeding habits are a little different.  Their main feeding routine involves “digging through the mud with their massive jaws and straining out the clouds of arthropods with their baleen, a process called benthic feeding,” Shaut said. In October, the pregnant females are the first to embark on the trip, needing to reach the warm lagoon waters to have their young.  The 60- to 70-degree lagoon water in Baja is beneficial to the animals because they do not have to rely on their depleted blubber stores to heat themselves.  “Upon their arrival in Baja, they are considerably skinnier as a result of making their journey,” Perryman said.  Another reason the lagoon waters of Baja are sought out by the whales is its high saline content.  “This results in the water being very buoyant and helps to keep calves afloat while they learn to swim,” Shaut said. One area of contention among gray whale experts is whether all of the whales make the journey south or if some linger behind.  “Whales are counted going south past central California and we have to assume that everybody migrates,” Perryman said.  If this is incorrect, it would obviously yield biased data, he added. “We are starting to suspect that they don’t all necessarily migrate every year,” Perryman said.  Shaut confirms the latter suspicion, saying she believes that not all whales make the migration.  “Some whales stay up north.  We will even see juveniles hanging out around San Diego, and when they encounter adults heading back north, they will turn around with them,” Shaut said. It was most likely a juvenile like this that became confused and stranded in the general area a decade ago.  SeaWorld animal rescue officials were in a position to help out.  “In January of 1997, J.J. [the juvenile whale] was found on the beach near Marina Del Rey.  The animal was dehydrated and malnourished, so we took her in,” SeaWorld communications director Dave Koontz said. The animal care staff at SeaWorld was able to create a baby whale milk formula from scratch to feed J.J.  “Nobody had done it before, but J.J. responded fairly quickly here at the park,” Koontz said. “J.J. was tube-fed in the initial stages and shortly after she was actually nursing from a device we created. She was slowly weaned off formula and put onto solid food, and thereafter quickly demonstrated an ability to forage and find food as a normal grey whale would in the ocean.” After 14 months of a successful rehabilitation — during which time J.J. grew from 14 feet to 30 feet in size — SeaWorld was able to reintroduce her to the wild.  “She was transferred to a Coast Guard vessel and taken off the coast a few miles and released,” Koontz said.  Koontz said J.J.’s release was timed with the northward migration of gray whales in the hope she would be taken in.  “Her GPS tracking device unfortunately fell off after three days, but it is our hope that J.J. is still out there swimming today,” Koontz said. Gray whale populations are slowly growing.  Because of worldwide protection efforts, their numbers rose so steadily that, in 1994, they were taken off of the endangered species list.  However, some natural threats still remain because orcas (killer whales) are their main predators.  “We see orca attacks more on the northbound migration and the mothers have to watch their calves,” Shaut said. “Around Monterey Bay is where we hear a lot about attacks happening, where there are many more orcas.” Along with natural threats, impacts from human beings still exist.  “They [the whales] encounter a lot of pollution, noise and boat traffic, so there are definitely obstacles along the way,” Shaut said.   Gray whales are protected by the Marine Mammal Protection Act (MMPA), and there are certain limits which define how close whale-watching boats can get to marine life.  Not coming within 100 yards is a widely accepted distance not to breach. “You cannot be within a certain distance of the whales.  If they happen to swim up to the boat to get a look at us, that is OK,” Shaut said.  “However, we cannot cut off their path or block their way at all.”  Shaut makes a special point of this when educating her team of naturalist whale-watching tour guides.    Several whale-watching tours are offering their services to bring animal lovers up close and personal with the aquatic creatures.  Just remember to keep respect and conservation in mind when coming to watch the journey of the gray whale.   Regional whale-watching tours: La Jolla • La Jolla Kayak guided tours. For information, call (858) 459-1114 or visit www.lajolla kayak.com. • Baja California Tours, Inc. For information, call (858) 454-7166 or visit www.bajaspecials.com.  Pacific Beach • Baja Expeditions Inc. For more information, call (858) 581-3311 or visit www.bajaex.com. Point Loma • H&M Landing.  For information, call (619) 222-1144 or visit www.sandiegowhalewatch.com. Downtown San Diego • San Diego Harbor Excursion.  For information, call (619) 234-4111 or visit www.sdhe.com.  • Hornblower Cruises and Events.  For information, call (619) 686-8715 or visit www.horn blower.com.