Serendipity: An Ecologist's Quest to Understand Nature

By James A. Estes; University of California Press; 2016; 275 pages; $29.95

In 1970, after completing a master's degree in biology (but never having even seen a sea otter), James Estes found himself recruited to spend two years studying otters around Amchitka Island in the western Aleutians. The job was to survey the population and distribution of the animals before and after the Cannikin nuclear test in 1971. Thus began a series of serendipitous events that led to a 50-year career working in the Aleutians and beyond to study complex ecosystem relationships between animals and their environments.

In this memoir of his life as a research scientist, Estes documents how fate led him to multiple adventures, partnerships with other scientists and discoveries. His goal, he says, is to share what he learned and how he learned it and then, beyond that, to explain something of how the science happened. In this way, the reader gets a very good idea of both the scientific process and how a life in science can be driven by curiosity and the joy of fieldwork.

The author, now in his 70s, remains a professor of ecology and evolutionary biology at the University of California, Santa Cruz. The recipient of many awards, Estes was elected to the National Academy of Sciences in 2014.

Although the book is heavy on scientific and technical detail, readers with a general interest in Alaska, wildlife, natural history and the way science proceeds from hypotheses to proofs will find much to appreciate here. Young people contemplating a science career might gain some significant insights into such a life.

The main focus of Estes' decades of work has been the relationship between sea otters, kelp beds and sea urchins. Sea otters were hunted nearly to extinction during the Russian and early American fur trade, and the fragmented way they recolonized the Aleutians presented a unique natural laboratory for his studies.

Estes found that, in areas lacking otters, urchins decimated kelps and left a barren seascape. With otters to eat the urchins, kelp forests thrived — and made a home for many other species. The otter became known as a "keystone" species, upholding the ecosystem much as a keystone in an arch keeps that architecture from collapse.

The one example of otters, kelps and urchins came to support a larger body of science related to complex connections among species and the importance of predators in ecosystems. Just in the Aleutians, Estes and his team showed how the presence or absence of otters influenced the diets of gulls and eagles, the abundance of fish and the growth and size of invertebrates. The presence of introduced foxes to islands also was shown to influence ecosystems; on fox-free islands, seabirds thrived and contributed nutrients to the land, resulting in three times as much plant biomass as on the islands with foxes.

Now that otters have very recently returned to historic numbers in portions of coastal Alaska, including Kachemak Bay and Southeast, even a casual observer can see the change — the return of kelp forests and the decline not just of urchins but other foods favored by otters. The human response has been mixed: Some appreciate otters as charismatic animals good for tourism and ecosystem health while others object to the competition. People as well as otters are fond of Dungeness crabs, clams, mussels, sea cucumbers and abalone. Otters are protected under the Marine Mammal Protection Act and may only be hunted by Alaska Natives for subsistence purposes.

The latter part of the book takes up the big shift that began in the early 1990s, when the sea otter population in the Aleutians began plummeting. Estes and his colleagues found that killer whales were more present in the coastal waters than in earlier decades and that their predation on otters could account for the decline. This led to a larger hypothesis known as the "sequential megafauna collapse." This still-controversial idea suggests that heavy commercial whaling in the North Pacific after World War II caused killer whales to move from a dependence on great whales to, in succession, harbor seals, sea lions and sea otters.

In a chapter titled "Whale Wars," Estes takes readers into what he calls the "darker corners of science," where some whale biologists were more than skeptical of the megafauna collapse theory. Their hostility, he concludes, was not a result of evaluating evidence, but a concern about policies and research funding.

Anyone who doubts that there are still plenty of mysteries to probe in our natural world will find proof here of how one question leads to another, and that surprises abound. Alaska has always been both a difficult place in which to conduct scientific research and among the most exciting. James Estes makes us understand that he was a lucky young man to have landed in the Aleutians — a place he loved for its remote beauty — and that those who follow him in the field of ecology might meet similar rewards.

Nancy Lord is a Homer-based writer and former Alaska writer laureate. Her books include "Fishcamp," "Beluga Days" and "Early Warming."