The Blue Whales of Baja
Story and photos by Michelle Gilders

Is a child, I witnessed my first whale ever – a blue whale. Admittedly it wasn't a real one, but the memory of it will be imprinted in my mind forever. This "counterfeit" blue whale was suspended from the ceiling of the British Museum of Natural History – a mighty blue mass of plastic and fiberglass. It was a lifeless, static embodiment of leviathan; but, it was enough to enthrall me. To really appreciate the whale though, one must venture beyond the dusty halls of museums and view the animal in its three dimensional liquid habitat: flowing, flying, in an all embracing, all supporting medium.

I first saw blue whales off the southwestern coast of Baja California in 1989 and have been fortunate enough to see them every year since. It was also my first trip to the peninsula. It was a memorable trip for many reasons, but seeing blue whales was perhaps the most astounding. There is such mystery surrounding these animals and they are now such a rarity, that it was hard to imagine, back in England, translating that hope into reality.
Blue whales are found in all of the world's oceans. They are immense animals by anyone's standards. Their scientific name, Balaenoptera musculus, is a name that is certainly suggestive of their size and strength. They can reach more than one hundred feet (33 meters) in length and weigh 180 tons (190,000 kg), the largest of all animals found in the Southern Hemisphere.

Blue whales have arteries so large that a small child could crawl through them. At birth they are 22 feet long (7.5 meters) and weigh 3.5 tons (3,500 kg). The blue whale calf gains about 200 pounds (90 kg) a day on its mother's fat and protein-rich milk, and will weigh 16.5 tons (17,000 kg) when it is weaned 7 or 8 months later.
All whales fall in the mammalian Order Cetacea. There are eighty recognized species of cetaceans and the waters of Baja are home to roughly one-fifth of those. Cetaceans are classified into two broad suborders: odontocetes and mysticetes, also referred to as toothed and baleen whales. Baleen is a fibrous material similar to keratin, of which fingernails are made. The baleen is arranged in plates along the upper jaw of mysticetes, such as the blue whale, with the bristle-like fibers projecting along the inside of the mouth. Unlike toothed whales, such as dolphins and sperm whales, the skulls of baleen whales are symmetrical; this is related to the fact that baleen whales do not use echolocation.

Whales are air breathing, fully aquatic mammals. Blue whales have a double blowhole, as do all baleen whales, while toothed whales have a single blowhole. Having a nose on top of the head is an ideal adaptation for marine animals, but it is one that took millions of years to evolve. All cetaceans also have a torpedo-like body shape, their front limbs modified to pectoral flippers (an elongated paddle-shape in the blue whale). They do not have any visible hind limbs; and, most species have a dorsal fin.

The tail flukes of whales and dolphins are horizontal, unlike the tails of fish, such as sharks, which are vertical.Cetaceans do not have external ears or ear muscles and they do not have scales or gills. All mammals have hair, but in whales it is often hard to see. Whales lack a covering of fur, but many baleen whales have sensitive hairs on their rostrums or snouts, and embryonic cetaceans show a covering of hair that disappears as the fetus develops. Cetaceans do not have sweat or sebaceous glands; instead, they have a thick layer of blubber, fat and oil beneath their skin that is used for insulation, heat regulation and energy storage.
It is hard to mistake a blue whale for anything else when seen from a boat. At the surface, the animal is slate or slightly grayish blue, with a mottling pattern on its back. In the moments before it surfaces, sending its blow 25 feet (8 meters) into the air – the tallest blow of any whale – it turns the water aquamarine.

Blue whales will often dive for 10-20 minutes at a time, although longer dives are certainly known. They will usually follow dives of that length with 8-15 blows at the surface. When blue whales fluke, the tail stock is dramatically thick and visibly powerful. As with other whales, blues will often repeat the surface, dive, and respiration patterns they establish. Under normal circumstances they swim at speeds of about 22 km/hr (13.5 mph), but can sustain speeds of 48 km/hr (30 mph) if frightened or chased. This is truly remarkable considering that we usually equate size with sloth rather than speed.

The dorsal fin on a blue whale is small relative to its body size. It is usually about 13 inches (33 cm) tall and tends to have a swept-back appearance. The fin is not as tall, sharp, or as obvious as that on other rorquals and at times it may look more like a bump than a true fin. The dorsal fin is a long way back on the animal's body, only appearing shortly before it dives. If you witness a blue whale lunge-feeding you will also see the numerous ventral grooves on its throat. These white pleats are very distinctive and have an almost rubber-like appearance. In the past, blue whales were called "sulphur bottom" whales, a term that referred to the sometimes yellow-coating of diatoms that take hold on their undersides and along their ventral grooves.

Blue whales are in the same family and genus as minke, Bryde's (pronounced Broo-dus), sei and fin whales. They are collectively known as rorquals. Rorqual is a Norwegian term that means "furrow whale" and refers to the numerous throat grooves that identify whales in this family. It is these grooves that allow the rorqual to expand its throat and take in more food and water as it feeds, typically on krill or small fish. Humpback whales have 10-36 throat grooves, while the blue whale may have as many as ninety-four.

Although other rorquals feed on fish, the blue whales' diet is almost exclusively krill. Krill are shrimp-like crustaceans, called euphausiids, typically less than 2 inches (5 cm.) in length. Krill often swarm in huge clouds in the upper water column and can be seen where currents meet, traveling where the water takes them, but also moving up and down in the water column on a diurnal cycle. Since blue whales may feed on 40 million individual krill each day, their feeding strategy has to be specific. It would be energetically inefficient if blue whales fed on small numbers of krill, so they concentrate only on the large groups.

Blue whales usually feed at depths of less than 300 feet (100 meters), and sometimes, when the krill is concentrated near the surface, they will lunge upwards, scooping up krill and water and revealing the black baleen in their cavernous mouths in a spectacular display of mass and power. Blue whales take full advantage of gravity when they lunge-feed, opening their mouths wide while they take in as much water and krill as possible, often tripling their mass. They then roll over onto their sides or back, allowing the weight of the water to push down against their baleen. In this way, the water streams through the baleen under its own force and the whale is left only to wipe the krill off the inside bristles with its tongue. Each blue whale has between 300-400 baleen plates attached to the upper part of its mouth, ranging in length from 20-40 inches (50-100 cm) each.

Rorquals (except humpback whales, which are somewhat unique) tend to be streamlined and they have broad, flat rostrums, sickle-shaped dorsal fins and short pectoral flippers. Blue, fin, sei, Bryde's and minke whales appear very similar, just in descending order of size. Of these rorquals, only the blue whale lifts its tail fluke out of the water on its dives, and then only infrequently. It is estimated that only 10-15 percent of the blue whale population flukes while diving. The streamlined rorquals simply do not need the extra impetus that this motion gives them, and fluking blue whales could be viewed as genetic relics of a time when all rorquals fluked. Blue whales are fast swimmers and do not support the colonies of barnacles on their flanks or throats that can be seen on gray or humpback whales, although the trailing edge of their flukes may carry some of these freeloaders.

It was the size of rorquals like the blue and fin whales that attracted commercial whalers. These large mammals are known for their rapid swimming speed, and this ability protected them from whaling until the advent of steamships.

In the single season of 1930-31, 29,410 blue whales were killed in Antarctic waters. This unsustainable take fell dramatically in subsequent years, with 12,559 taken in 1939-40, and 6,313 in 1949-50. In total, 328,177 blue whales were killed in the Antarctic between 1909 to 1965. In the early 1960s, the International Whaling Commission began various measures to protect the whales, but non- compliance from a number of whaling nations effectively negated that protection. It was only in 1966, when the animal was believed to be commercially and possibly even biologically extinct, that a complete cessation of whaling was implemented.
Blue whales have been elusive animals to study. The pre-whaling population of 220,000 to 240,000 individuals has been reduced to probably less than 12,500 and recovery is proceeding at a painfully slow rate. Truthfully, no one knows how many blue whales are left. Whales are difficult and expensive to count, and those species for which we have sound population data tend to be coastal for at least part of the year.

Before commercial whaling, the majority of blue whales, perhaps as many as 90 percent, lived in the Southern Hemisphere. Today the healthiest population of blues is in the North Pacific (which includes the Baja population). Some estimates put this population as high as 2,500. Blue whales spend the winter in temperate and tropical waters, probably mating and giving birth to their young during that time. Female blue whales give birth to a single calf every 2-3 years, after carrying that calf for 10-12 months. There have been records of twins from the decks of whaling vessels, but it is very unlikely that a blue whale could bring two fetuses successfully to term.

Although groups of blue whales may be seen together, researchers do not know how permanent, if at all, these groupings are. The core of blue whale "society" is the cow and calf. All other groups of blue whales are believed to simply reflect animals coming together using the same, localized resource.

Blue whales migrate to high latitudes during the summer, feeding in the rich, cold waters. In the Southern Hemisphere blue whales venture farther south into Antarctic waters than the other rorquals, while in the Northern Hemisphere they tend to concentrate in the North Pacific (into the Gulf of Alaska and the Bering Sea) and the North Atlantic. Each population is believed to be divided into distinct genetic stocks that do not intermix on a frequent basis; this is one of the reasons why stock recovery is believed to be taking so long.
Most baleen whales feed primarily on their summering grounds; however, blue whales are known to feed all year round. This year-round feeding is probably dictated by their large size – they simply cannot sustain themselves by feeding for only half the year.

Whaling data has given us a great deal of information on size, weight and reproduction of this magnificent animal. It is very difficult to age baleen whales, however, since they lack the teeth that can be so conveniently sectioned in toothed whale species. Whaling records and estimates based on morphological features, (especially sectioning the wax plugs that collect in the ear canal), suggest that some blues can reach ages of 110 years old, similar to the upper age range of several other cetacean species.

There is so much that we have yet to learn. We know little about whale migration routes, where their calves are born, their mating, social structure and communication. And these are things that cannot be learned by wastefully killing whales.

Today, researchers are able to study individual blue whales, something that is essential if we are to begin to unravel the more intimate and social aspects of their lives without resorting to destructive harvesting. Individual whales are identified by the distinctive mottling patterns around their small, sickle-shaped dorsal fins. These markings are not as easy to see as the well-known humpback whale fluke patterns, but are going a long way in helping researchers develop a database of animals that can be used to determine migration routes and group associations.

Scientists have also recently begun putting radio-tags and satellite transmitters on blue whales off the northern California coast, in hope that the data collected will tell them more about blue whale distribution and behavior. This is a time consuming and expensive approach, but even a small sample of tagged animals will provide valuable data. Other research involves looking at genetics by collecting small samples of tissue using cross-bow bolts shot at the back of a retreating whale. The bolts do not cause any permanent damage to the whale, but do enable researchers to collect enough tissue to run DNA tests and perhaps help to establish family-trees for discrete populations.

One of the most remarkable discoveries to emerge about blue whales is that they use very low frequency sounds, 20-60 Hz, with high source levels of more than 188 dB (equivalent to an airliner taking off). This is the most powerful natural sound produced in the animal kingdom. Little is known about how, or why, the whales use these sounds. They may use low frequency sounds, and some higher frequency clicks to locate krill, but they do not have an echolocation system that is anywhere near the sophistication of sperm whales or dolphins.
Some have postulated that before the oceans became the noisy places they are today, filled with tankers, boats and submarines, blue whales could be heard around the world. It is intriguing to speculate that they may use sound to map their migration routes, or keep in contact with animals oceans away. The U.S. Navy is using these same low frequencies to map large portions of the seabed. As we learn more of the blue whales' ability to project low frequency sound over vast distances, we may have to rethink our view of these great whales as relatively solitary animals.

I will never forget the first time I saw a blue whale. It was a magical experience multiplied seven times and cradled in the warm, calm waters of the Pacific:

Since that first experience, I have watched bottlenose dolphins bow-ride off the snouts of blue whales and a 35-foot, four-month old juvenile play around our boat while its mother dozed at the surface 300 feet away. Every blue whale I have seen has been memorable, even those half hidden in fog have emitted a powerful presence. The blue whale is the pinnacle of the whale-watching experience. With few blue whales remaining, the chance to see one is made all the more special, tinged perhaps with an element of sorrow.
Whale-watching requires a great deal of patience and a good eye. When you are on the water, look for anything that stands out as unusual or different – a flash of sunlight on the flank of an animal as it surfaces, a group of birds on the water, a distant blow, a splash or wave that doesn't quite fit in with surrounding conditions.

Approach the animals slowly. Don't make any sudden gear shifts as reversing gears often startles whales. Head towards the whales at an angle, not from directly behind or in front. Never pursue whales. You want to record naturally occurring behavior, not pursuit.

Watch the whales' behavior carefully. They often demonstrate a regularity in their actions. If a whale surfaces and blows 8-10 times and then dives for ten minutes, it will often repeat this routine. Watch for the flukeprint (the calm, circular slick of water that results from the down thrust of the whale's flukes); it often appears on the surface after a dive, or when the whale is swimming just beneath the surface. By gauging how fast the animal is swimming you can guess where it will surface. In blue whales, the sight of the small dorsal fin, often with a slight hunching of the back, is an indication of a dive and possibly that the animal will fluke.

Blue whales, like most marine mammals, can be elusive, and sometimes appear with little warning. You can maximize your chance of seeing these whales before they surface by wearing polarized sunglasses. Polarized lenses cut down the glare on the surface of the water and will enable you to see the blue-green shadow of the whale before it breaks the surface – allowing you to get ready for that once-in-a-lifetime photograph. It is also a good idea to use a polarizing filter on your camera to increase the contrast and eliminate the glare from your images.

Baja California is a whale-watchers' paradise. There are few other places that harbor such a concentration and diversity of whales. Although there are reports of blue whales being seen throughout the year in Baja, the best time is January through April. Blue whale ‘hot-spots' are found near Loreto and the surrounding islands of Monserrate, Santa Catalina and Santa Cruz and in the lower part of the Sea of Cortés. There are day trips offered from a number of Baja's port towns, but the best way to see blue whales is to immerse yourself in their environment, and to take to the water for extended periods of time.

Maybe it is their size, our perception of their gentleness, their interaction with others of their own kind, or the tales founded in myth, legend and reality of their interaction with humans that attracts us. Or maybe it is the knowledge that we came so close to losing them. No matter what the reason, there are few people who are not awed at the sight of a great whale ascending from the depths.

We do not know how many whales are left, but as development continues along our coasts, it is becoming even more important that we take the time to study the whales and learn their secrets. If we do not, we may soon find the oceans silent, and the surface stilled. The world's oceans were once filled with blue whales, today the sight of a whale blowing on the horizon is sadly rare, except perhaps in the beautiful waters that surround the Baja Peninsula – a sight to be cherished.

Michelle Gilders was born in Hitchin, England and received her Bachelor's and Master's degrees in Pure and Applied Biology at New College, Oxford University. She is the author of "Reflections of a Whale-watcher" (Indiana University Press, 1995) and "Crossing Alaska" (Graphic Arts Publishing Company), due out in June, 1997. Michelle lives in North Vancouver, British Columbia, where she works as a writer, biologist and photographer. She travels extensively, including annual trips to Baja, mainly in search of marine mammals. Her ultimate goal is to observe for herself all of the eighty recognized species of cetaceans. Copies of "Reflections of a Whale-watcher" can be ordered from Indiana University Press at 1-800-842-6796.
Whale-Watching Tours

Several tour operators run whale-watching trips at the time when blue whales frequent Baja's waters.