vide a sheltered habitat for the 

 algae, which might otherwise be 

 swept away by the waves. When 

 tides are high, the anemones un- 

 furl their crowns of tentacles into 

 the sea, snagging mussels that 

 float by. At the same time, pho- 

 tosynthetic algae in their guts, ex- 

 posed to sunlight, provide added 

 nourishment to both themselves 

 and their anemone hosts. Algae 

 and anemones form a partnership 

 that works. 



So, too, do Mimi Koehl and 

 Anne Wertheim Rosenfeld. 

 Koehl, a Berkeley professor, is 

 an expert in biomechanics. She 

 has made her mark in studying 

 how the structures of organisms 

 help them function in particu- 

 lar environments. Why, for in- 

 stance, aren't starfish peeled 

 from rocks by the surt ? (The an- 

 swer: hard grit embedded in ex- 

 posed areas of soft tissues makes 

 them stiff enough to resist breakage; 

 underneath, hundreds of tubelike feet 

 hold the starfish in place.) Rosenfeld, 

 by contrast, is a veteran nature pho- 

 tographer; eighty-seven of her exquis- 

 ite pictures of the creatures and micro- 

 inhabitants along a short stretch of Cal- 

 ifornia coast provide an eye-catching 

 and instructive accompaniment to 

 Koehl's descriptive prose. 



Wave- Swept Sliorc is a field guide not 

 to the creatures that inhabit the inter- 

 tidal zone, but to the processes that en- 

 able them to live together in such a 

 challenging habitat. In a few short 

 chapters Koehl shows how their design 

 helps them deal with the challenge of 

 an environment that is alternately dry 

 and wet, scoured by surging currents 

 and dessicating winds. How do plants 

 and animals anchor themselves? How 

 do they protect their bodies against the 

 relentless stress of flowing water? How 

 do they find food, eliminate wastes, 

 and reproduce? 



Leafing through the book, its clear 

 that nature has devised a variety of so- 

 lutions to these problems. Some littoral 

 creatures — barnacles, for instance — 



Eddies that form between rocks as tides ebb and flow 

 stir up the water and draw away wastes from the 

 animals and plants that live on the shore. 



secrete a remarkable glue that bonds 

 them so firmly, even to wet surfaces, 

 that they can weather the fiercest storm. 

 When they get amorous, though, they 

 are, literally, stuck. Unlike crabs, which 

 can scuttle long distances in search of a 

 mate, barnacles can only marry as it 

 were, the girl next-door. To this end, 

 each one (barnacles are hermaphro- 

 dites) has a penis long enough to reach 

 other nearby barnacles. "If you bolt a 

 camera to the rocks to record what bar- 

 nacles do when the tide is in," writes 

 Koehl, you'll see that, when they are 

 not filtering food from the water, they 

 are "snuffling around the neighbor- 

 hood with their penises, perhaps 

 checking out potential mates." 



For barnacles and most other crea- 

 tures of the intertidal zone, the con- 

 stant waves are both a curse and a bless- 

 ing. Many adaptations arc, in essence, 

 protective measures against the flow of 

 water — protective shells, streamlined 

 shapes, suckers that cling and adhesives 

 that stick. But tidal creatures also de- 

 pend on moving water to bring in the 

 microplankton they eat, to scatter eggs 

 and distribute larvae, and to dilute and 



flush away wastes. "Try to feel the en- 

 vironment met by the animals and 

 plants clinging to these rocks," Koehl 

 advises. Together she and Rosenfeld 

 ably do just that, conveying the feeling 

 that — for sea squirts, mussels, and 

 goose barnacles at least — the rocky 

 coast is the best of all possible worlds. 



Fish on Friday: Feasting, Fasting 

 and the Discoi>ery of the New World 

 by Brian Fagan 

 Basic Books, 2006; $26.95 



Fish have been a culinary delicacy in 

 most cultures, yet oddly, in most of 

 medieval Europe, they were regarded 

 as something of an acquired taste. For 

 centuries, the Catholic Church judged 

 that eating fish was a form of self- 

 denial, and permitted its consumption 

 on fast days when other, more desirable 

 foods were banned. The days of fasting 

 and penance included the forty days of 

 Lent, as well as Fridays and miscellaneous 

 holy days. As the Church came to dom- 

 inate European society, an enormous 

 demand for fish developed that, even- 

 tually, local resources could not supply. 



Brian Fagan, emeritus professor of an- 

 thropology at the University of Califor- 

 nia, Santa Barbara, weaves these themes 

 together into a fascinating history of the 

 fishing industry in Europe, from Roman 

 times until the colonization of North 

 America in the 1600s. It would be an 

 overstatement to argue that the New 

 World was settled because Catholics 

 needed fish to obey ecclesiastical stric- 

 tures. But Fagan makes an excellent case 

 that the lure of rich fishing grounds 

 should be given equal weight, with the 

 quest for gold and spices, as forces that 

 drove Europe's westward expansion. 



Until the eleventh or twelfth century, 

 according to Fagan, most fishing was 

 done locally. Eels w ere among the most 

 abundant species, and were so prized 

 that in some markets they were used as 

 a form of currency (one can only imag- 

 ine how modern vending machines 

 would work if the practice had contin- 

 ued). Herring were also abundant, but 



May 2006 NATUH.AI HISTORY 



