The good news is, the sharks are coming back

 kw: book reviews, nonfiction, science, oceanography, fish, sharks, memoirs

This mug shot of a white shark was recorded with a pole camera. It is used to identify the shark when it is seen again. Look carefully at the boundary between the white underside and the gray back of the shark, particularly the wiggly part just forward of the pectoral fin. Also, the head has numerous scars, many of them from the claws of seals the shark has eaten. All these markings are distinctive, and the older a shark is, the more unique features it accumulates.

Oceanographer Greg Skomal and his colleagues have compiled "ID pictures" for a few hundred sharks in their efforts to produce a census of sorts of the occurrence of white sharks in the waters off Massachusetts and New England. They have also tagged a couple of hundred of them with acoustic tags, which regularly "ping" a series of buoys off Cape Cod and the Massachusetts when the animals enter the area, or with recording tags that track their movements. The work is described in Dr. Skomal's memoir/documentary book Chasing Shadows: My Life Tracking the Great White Shark.

Here we see him on the "pulpit" of a shark-tagging boat, getting a pole camera ready, as the boat approaches a few sharks that were spotted from an airplane, including the one above. I clipped these two images from one of the many videos of Dr. Skomal's work as a shark researcher.

He gained his passion for studying sharks when he saw Jaws as a youngster. During his college years he expected one day to move to California, where a white shark "hot spot" is found near the Farallon Islands. Once he completed undergraduate studies in Massachusetts in 1983, however, white sharks were occasionally being seen in the area, and his relationship with the oceanographers was such that he was reluctant to leave. He eventually stayed, first spending a few years on Martha's Vineyard and later landside, and now heads shark research in the whole area.

He came along just in time. White sharks had been almost absent for many years, mostly because their preferred prey, seals, had been hunted nearly to extinction because of state bounties. Saltwater fishing tournaments, which formerly treated all sharks as "trash fish" and "vermin", began expanding their purview, and then specialized "monster tournaments" began, targeting sharks, and the great white shark in particular. But for years, white sharks were quite rare compared to blue sharks and mako sharks and a few others.

With the end of the bounty, the seals began to return. The rocky areas around Cape Cod are prime seal nursery habitat and haulout areas. White sharks followed. Now there are hundreds, although other shark species number in the thousands. Tagging that targeted white sharks in particular began as a definitely side endeavor. The book details the growth of this "tail" until it began to "wag the dog". The changeover occupied the late 1980's and 1990's. 

Here we see Dr. Skomal on the pulpit, from a better vantage point (the airplane), just after he has placed a recording tag behind the dorsal fin of a shark that appears to be nine feet long, so its age may be twelve years.

White sharks live about seventy years, similar to our longevity, and they begin to procreate by age twenty, also like us. However, they do not care for the young after they are born. Instead, a female shark has a double uterus, into which several eggs are placed. The first baby shark to hatch in each side gradually eats the other eggs, so the total gestation time is about twice as long as humans', while the babies grow to a size of 4-5 feet. Once the babies are born they are on their own.

As you may imagine, the greatly increasing presence of these large predators—as large as twenty feet—in coastal waters near extremely popular swimming beaches has many people upset. However, the efforts of Dr. Skomal and many other oceanographers to educate the public, and to try to allay the unrealistic fears engendered by the Jaws films, brought many people to realize that these animals are necessary for a healthy ecosystem. White sharks in the Atlantic were listed as Vulnerable in 1997 and have been federally protected since then; Pacific white sharks were listed a few years earlier.

Several encounters people have had with white sharks in waters off Massachusetts and New England are detailed. A few of them were fatal. A few others were severe, and the victims spent months or years recovering. Some were bad scares that left tooth marks on boogie boards or kayaks, for example. Understandably, fatal shark attacks cause great consternation in coastal towns and their residents. Dr. Skomal has had to walk a fine line between defending the sharks and educating the people among whom he lives, to avoid charges of "caring more about science than people's lives".

In spite of much greater numbers of these sharks in New England's waters since 1990 or so, these animals are elusive and their behavior is not as well known as we would like. People who like to kayak out to be among the seals are basically walking in front of a loaded shotgun with a hair trigger. To my way of thinking, that's a way to earn a Darwin Award. Quite a number of "shark mitigation" methods have been discussed over the years. Based on experiences in Australia and South Africa, it is known that none of them is 100% effective. We in the West have gotten used to being the apex predator for a few generations, while in other parts of the world, there are still tigers or hippos, etc., that take a few lives yearly (many more than sharks, actually). 

Now America's well-heeled "elites" find themselves sharing the water with a real apex predator, one we cannot drive out or completely destroy. Knowing their habits is the best way to avoid getting in their crosshairs. Humans aren't their preferred prey, seals are. But a human swimming or paddling looks enough like an injured or naïve seal that a shark might take an exploratory bite to see "what is that thing?". Such a bite, from a mouth two feet wide full of 3-inch, serrated teeth, can well be fatal. And the shark was "just checking". The more research, the more learning, the better!

This informative and engaging book can educate us all. I hope it gets very wide circulation.

Fun with the fishes

kw: book reviews, nonfiction, fish, ichthyology

These two little fish, a lanternfish above and a bristlemouth below, may be the most abundant animals on earth. They live about a kilometer deep in the sea, and there are probably a few million billion (that is, about 5,000,000,000,000,000) of each in the sea. That is, around a million of each of these little fish per living human. That is about equal to the total number of termites on (and in) land. This picture shows them around half size, so they are much larger than termites. If there are 1,000 pounds of termites per person, there are close to 1,000 tons of just these two fish, per person. According to this article, one genus of bristlemouth is the most abundant, edging out the lanternfish.

Other fish aren't quite so abundant. Oh, there are a lot of fish in the sea, but not nearly as many as there were before industrial fishing began in the 1800's. Small, bony, bad-tasting fish like bristlemouths haven't been affected, but many, many other kinds of (tasty) fish are only about 1/10th as abundant as they were 100-200 years ago. Further, many kinds of less-tasty ones are destroyed as bycatch, caught in the nets and trawls and discarded dying or dead.

This Gulper Eel is in the running as "ugliest fish", but I think it rather charming. It's a sure bet that Gulper Eels like each other, at least around breeding time, no matter what we might think of them. Fish in general are fascinating. While I like going to a zoo to see the mammals and birds, I adore aquariums. They are just a bit more scarce, and cost more to run, yet are incredibly popular in spite of higher admission fees.

Eye of the Shoal: A Fishwatcher's Guide to Life, the Ocean, and Everything, by Helen Scales, just touches the surface of the huge variety of fish stories that could be told. She tells us a bit about how many major groups of fish there are and what they are like, and discusses ten fish-related subjects, in an enjoyable, readable way. And I must mention the illustrator, Aaron John Gregory.

Ask anyone, "What does a fish look like?", and you'll probably get a description that is pretty much like this yellow perch. You can catch these lovely, pan-size fish in many lakes and streams throughout North America. You could make a checklist: Longish oval shape, a fin or two on top and bottom and sides, scales, forked tail, and so forth. Ninety percent of all species of fish are kind of like that, and are called Teleosts ("perfect bone") or "ray-finned" fish.

But some fish don't have bones. Think sharks, skates, and rays. Their skeleton is composed of cartilage, like the easily broken stuff that gives your nose its shape. Some don't have scales, such as eels (well, actually, they have very tiny scales) and adult swordfish. Some fish, though they have bones, don't have jaws. Lampreys and hagfish are the best known (but maybe you never heard of them). Some fish have few bones; a spine but little else, such as puffer fish.

And by the way, fishes of the most common genus of puffer fish, Tetraodon, contain extremely poisonous tetrodotoxin in parts of their bodies, making them the most dangerous fish to eat. Even with strict licensing of sashimi chefs in Japan, every year a few people die from eating puffer fish called fugu that weren't quite prepared right.

For most of us, our main exposure to fish outside of a public aquarium is in the kitchen or restaurant. Most people enjoy eating fish, and the local grocery store usually has a fish counter where you can buy salmon, perch, tilapia, and perhaps trout, bream, and maybe catfish…plus various non-fish such as clams, shrimp and mussels. About 3/4 of the world's people get most of their protein from fish, which is why so many species of popular fish are seriously overfished.

There is a chapter near the end of the book that discusses this problem, and the lack of any useful solutions. Fish farming can make a certain amount of difference, but probably not enough. Along with all the other dangers we cause because of the sheer number of people on Earth, we are eating our way to eventual starvation for many.

I can't end this without one more picture, this time of the biggest fish it is safe to approach, the Mola Mola sunfish. This one is a "mere" 10 feet "tall" (fin tip to fin tip); they get as large as 14 feet and weigh up to 2.5 tons. Ocean sunfish are curious about people and not aggressive.

With some 20,000 species, fish are the most abundant vertebrates. This book just whets the appetite for learning more and more about them.

Taming the seas

kw: book reviews, nonfiction, domestication, animals, fish

Certain conditions for the successful domestication of an animal were laid out by Francis Galton in an 1865 article, "The First Steps towards the Domestication of Animals" (Trans. Ethnological Soc. London, vIII, pp 122-137):

• Hardiness
• Fondness for Man (or at least Tolerance)
• Desire of Comfort
• Usefulness to Man
• Breeding Freely (i.e. in all seasons)
• Gregarious or Loyal and thus Easy to Tend

These traits have led historically to the domestication of livestock, such as cattle, sheep, swine and horses, and to certain pets, notably dogs. House cats are the prime example of an animal that is not gregarious, but is extraordinarily loyal to the comforts of a home. Can these criteria be applied to fish, and thus guide our efforts to "farm" them?

Paul Greenberg believes they can, and must be, so applied. In his book Four Fish:The Future of the Last Wild Food, he presents the demise of the wild fishery upon which much of human nutrition has depended, and its replacement by fish ranching. It is a bittersweet transition.

After growing up an avid fisherman, as an adult he noticed that fish markets displayed little of the diversity of the past, and had become dominated by just four varieties of fish: Salmon, Sea Bass, Cod and Tuna. The short version of his message is that salmon in the market are already mostly farmed, certain representatives of the "bass" and "cod" prototypes are getting that way, but tuna are unlikely ever to be a "manageable" fish, primarily because of Galton's principles. If a prediction made by Galton is accurate, we may thus expect the total extirpation of all species of tuna during this century, for "they are doomed to be gradually destroyed off the face of the earth as useless consumers of cultivated produce." While Galton was writing of land animals, it is likely that, once we have fished tuna to near extinction, the perception of them will shift to match that once attributed to wolves, as voracious competitors for fish we'd rather eat ourselves.

The book is composed of four long chapters, one per type of fish, plus a long concluding essay on what is needed for a sustainable fishery. To pick the most important criterion, I rely on that which informs sustainable sport hunting: most meat for most people is taken from domestic stock (in this case farmed fish), with smaller numbers left to sports fishermen. The "profession" of fisherman would thus go the way of the market hunter.

What is the possibility that any fish really matches all the Galton criteria? Pretty good, really. Two standouts: Kahala and Tilapia, one marine, one a freshwater fish. I've eaten farmed tilapia, and it is an excellent whitefish. In other words, it has the potential to replace bass and cod on the menu. The kahala, in the midst of being renamed "Kona Kampachi", could replace fattier fish like tuna. Where most "bass" type fish and all tuna will thrash themselves to death against nets meant to contain them, these fish are tolerant of confinement and, while not particularly "fond of man", are at least tolerant of being "managed".

In order to get ground truth on the state of each variety of the four fish, the author traveled the world, participating in sport fishing expeditions and visiting fish farms of all kinds. His is a mostly optimistic message. He hopes fisheries management will become more rational, but mostly we must rely on the power of human desperation: we will do better once it becomes absolutely imperative because our own survival depends on it. Agriculture resulted from such a paradigm shift about ten thousand years ago. We did it before, and we can do it again.

Eels are people too

kw: book reviews, nonfiction, natural history, fish, eels

This large freshwater eel from Singapore is typical of Asian eels in its mottled color, but is otherwise similar to eels found worldwide (Image from The Lazy Lizard's Tales). Most freshwater eels are dark brown or black. A strange fact: The food provided by Indians to the English immigrants, commemorated in Thanksgiving celebrations, was largely an eel feast, with venison a minor component.

Freshwater Eels are catadromous, meaning they move downstream and out into the ocean to breed; "cata" means "down". This is in contrast to salmon and shad, which are anadromous, moving from the ocean upstream to breed; "ana" means "up". Just where the eels breed is still not known in any detail, and eels remain very mysterious, as described in Eels: An Exploration, From New Zealand to the Sargasso, of the World's Most Mysterious Fish by James Prosek. Eels from around the Atlantic are known to breed somewhere in the Sargasso Sea, and Asian eels have very recently been caught, dying, a few days after breeding, but despite a century's diligent effort, they have never been observed breeding.

Author James Prosek traveled the world, initially searching for the facts of eel biology and ecology. After several years he found he was learning much more of eel folklore and mythology. While in most places eels are a food animal, the Lasialap people of Pohnpei (formerly Ponape) Island in Micronesia believe they are descended from eels, and look upon the eating of eels with horror. Although the Maori of New Zealand eat eels, their folklore is filled with cautionary tales of those who would abuse them, and with stories of the taniwha (pronounced "tanifa"), or guardian eels.

Like every other ocean resource, the eel fishery is collapsing worldwide. This has led to an immense trade in glass eels, the first post-larval stage when they are 4-5 cm in length, which are used to stock rivers and lakes for "fattening up". Current prices for glass eels are a few hundred dollars per pound. Imagine what a five-ton shipment of glass eels from Maine is worth!

One of the author's long-term friends has been Ray Turner, who maintains an eel weir near Peas Eddy in New York State. Each year he endeavors to capture something like a thousand eels from the many thousands who migrate downstream into the Delaware River each year. When the weather doesn't cooperate, he'll capture only a fraction of that. Prosek returned year after year to Peas Eddy, and was able to gradually participate in most aspects of the commercial eel business of which Turner is a part.

Though freshwater eel numbers from all nineteen species are crashing nearly everywhere, there is as yet no designation of them as either endangered or threatened, particularly in the U.S. Activists that Prosek got to know believe this is political. Eels are found throughout North American watersheds, and an Endangered designation would disrupt activities along all the continent's rivers. But it is precisely those activities, damming for hydropower and "recreation", and commerce with its effluents, that prevent eels from completing their life cycles. At one time the Great Lakes and the St. Lawrence River were the premier eel growing areas; no more. There is too much that is in their way now. The Delaware is the main river of the Eastern American seaboard that is not dammed every few miles, and is the last major eel growing region. The nearby Susquehanna River is nearly eel-free now. If eels were more "warm and cuddly"—they happen to be cold and slimy—they would probably get more respect. There are few who stand up for them.

There is an interesting parallel between the history of the Atlantic eel species and that of the green sea turtles. Both migrate thousands of miles to breed. Both are about 200 million years old. Both apparently began breeding, the turtles on the Azores, the eels in mid-water, when the Atlantic Ocean first opened. As the ocean widened over the millennia, both gradually adapted and honed their navigation skills, so as to find their breeding grounds as these were taken farther and farther from the coasts of America and Africa and Europe by continental motions. Prosek tells the story of the eels' evolution, and I happened to know already of that of the turtles.

The book is a real eye-opener. The eels' story is a lot like our story. They live up to 100 years, just as people do. They are easily tamed, and have personalities. They have become a worldwide success over those millions of years, but this upstart primate species is taking over the rivers, to the point that eels are getting squeezed out. Only in places where they are revered are they in any sense still thriving. The book, first conceived as a recipe book, became a spiritual journey for its author. This mysterious fish, which can travel overland if needed to reach its goal, deserves to be better known.

More fish

kw: photographs, animals, fish

A few more pictures taken at the Georgia Aquarium May 27, 2010. We spent the whole day there.

Jellyfish. They are white; the color is from colored lights that change slowly. A kind of living light show.

A manta about to do a backflip in front of the big window.

Freshwater tropical fish, just a bit bigger than you can usually get at the pet store. There were also neon tetras in this tank, but these are the size of a hand and larger.

Some ghostly sea anemones. I had to take this at very high EV, so it looks grainy.

Across from the aquarium is Centennial Olympic Park, which is paved with engraved bricks. Take a second look at the one in the center (click on any of these for an image about twice the size).