Local beaches and offshore waters appear to be teeming with greater numbers of crowd-pleasing — and even rarely seen — marine life this summer. July boasted sunny skies and warmer water, attracting heavy crowds to the beaches and unusual numbers of sea life for this time of year, according to experts. Killer whales that typically prefer colder waters have been sighted enjoying the nearby ocean for several weeks. Rare giant jellyfish, known as black sea nettles, have drifted onto San Diego beaches in large numbers. Blue whales, the largest animals on Earth, are typical visitors for this time of year. Even these behemoths seem to be increasing in numbers, according to observers. The blue whales, which normally are found several miles out at sea, have recently been observed from the shoreline in La Jolla. Bottlenose dolphins have also been spotted enjoying the surf along Sunset Cliffs and Ocean Beach. The Risso’s dolphin species, another a rare visitor to local waters, has lately been entertaining boaters out in deeper water. Experts in the field agree that the recent swell in marine-life populations is due to the animals following their food supply. Experts said other species, like the black sea nettle jellyfish, are showing up in greater numbers because they are drifting along with the upwelling of deep-ocean currents. In July, dozens of the dark-burgundy colored jellyfish were spotted in San Diego Bay along the Point Loma shoreline. According to Craig Barilotti, a marine biologist who lives in Point Loma, black sea nettles are relatively rare and are usually found in deep water along the Pacific Coast. Barilotti said this particular species is actually more complex than most jellyfish and often has a main body — or “bell” — that measures up to three feet and tentacles extending up to 25 feet.  The species is carnivorous and preys on plankton and other jellyfish. To humans, their sting is nonlethal, but painful, and contact should be avoided, said Barilotti. And the proliferation of unusual sightings doesn’t stop there. “We’re seeing more sea life now than ever before,” claims Janet Morris of the Natural History Museum in Balboa Park. As the director of the museum’s volunteers, Morris said, “I recently have been getting reports of large numbers of marine mammals and sightings of rare species to this area. My understanding is that the cold-water upwellings are providing the food source, such as plankton and krill, that is currently attracting the higher organisms, such as whales and dolphins.” Leslee Matsushige, assistant curator for the Birch Aquarium at Scripps, agrees. “The water temperature these days is typical for San Diego summers,” she said. “Warmer waters, combined with upwelling, leads to plankton blooms that attract marine life to the area.” And those aren’t the only spectacles for local beachgoers, said Cammie Ingram, a marine biologist and administrator at Scripps Institution of Oceanography, noting, “We’ve been having an amazing algal bloom in the near-shore waters this summer.” Robert Pitman, a marine biologist for the National Oceanographic and Atmospheric Administration’s National Marine Fisheries Service, said, “the blue whale numbers appear to have mushroomed and they’re coming closer to the shoreline. I occasionally see them from my office in La Jolla. The Marine Mammal Protection Act of 1972 is the primary reason that the numbers have increased over the years.” But offshore marine-mammal sightings have also been rich, said Rick Scott, captain of the Ocean Odyssey at H&M Landing. “Our summer whale watching trips are now better than ever,” he said. “We’re seeing lots of sea life, along with good numbers of blue whales and a few killer whales. The blues don’t appear to be afraid of us. It’s like they’re enjoying swimming alongside and underneath our boat, behaviors that I’ve never seen before.” Adventure-seekers interested in experiencing an offshore sea-life experience can call the San Diego Natural History Museum Whalers at (877) 946-7797 to purchase tickets at a discounted rate, and H&M Landing at (619) 222-1144 to make the reservations for a trip.