Underwater in the Great Bear Rainforest the reef diversity changes abruptly, unlike anything on land. British Columbia has approximately 7,000 known marine species, a number that could double if we started looking seriously. The lion’s share of these, about 95%, are invertebrates, including 68 species of sea stars, 75 species of sea anemones, nearly 500 species of polychaete sea worms and more than 100 species of nudibranchs, a type of mollusc. The number of the much more celebrated vertebrate species of marine mammals, birds and fish hasn’t yet topped 600. Going slowly and focusing on this smaller world under water, I’m reminded of how globally exceptional the diversity of our marine environment is.

The steep rock face has a dusting of feather stars and a few rock scallops, and a resident candy-striped shrimp scampers about in the embrace of a crimson anemone as a lumbering, teacup-sized orange nudibranch forages on soft purple coral. Off to the side, a great school of quillback and grey-black rockfish swim uphill against the surge.

Later in the day, after three separate dives, Thomas, my team and I sail further west. As far as five kilometres (three miles) away we can hear above the ocean surf the deep roar of a thousand Steller sea lions barricading the verdant slopes of honeycombed nesting burrows that rise into the clouds above one of the islands. I look at Thomas. We are both contemplating all that we have just observed on the dives. Thomas has dived professionally for National Geographic in most of the world’s remote oceans. ‘The best of the best, my friend,’ he says. I couldn’t agree more.

As the longer days of spring loosen winter’s grip, the people of Bella Bella, Klemtu, Gitxaala and other traditional herring-spawning territories on the north coast focus on what locals call ‘herring weather’. The great diversity and plethora of wildlife in Great Bear is mirrored by the richness of its people, with whom we have worked closely. There are a dozen different First Nation groups along the Great Bear and each one has diverse and unique environments in their traditional territories. The Heiltsuk Nation is fortunate to have some of the most productive herring spawning grounds in its territory and has been at the forefront of the conservation battles to protect this endangered foundation fish species.

The tides, bird and mammal life, and air and water temperature indicate much about when the herring spawn will begin. People here follow the lunar cycle closely, and in Heiltsuk culture ‘when the moon tips over’ marks the beginning of one of the greatest and rarely observed natural events on the planet. This seasonal spawning event is so important, so vital and culturally revered, it signals the beginning of the traditional Heiltsuk New Year.

Soon after the herring schools move inshore and the ocean turns milky with milt and sperm, the females discharge their eggs, 20,000 per fish. Eventually six million eggs per square metre (about half a million eggs per square foot) will float with the tide, waiting to rest on seaweed, rock or other substrate material. One out of every ten thousand eggs will produce an adult. With luck, the logs begin to dip under the weight of multiple layers of tiny eggs building up on the hanging garden below.

It is one of those calm mornings in early spring when fog hangs over the coast. The water in Seaforth Channel is covered in a thin layer of bubbles as the herring rise from the depths and expel air from their bladders. These curtains of bubbles are thought to confuse predators. As each herring expels air, a small acoustic blip can be heard like hard rain hitting the water. The late Heiltsuk elder Ed Martin told me that hunters used to carry small round pebbles in their canoes and gently toss them into the water to mimic the sound of herring; sea lions, dolphins and other prey would come inshore attracted to the familiar sound.

Thousands of surf scoters rafted in large black mats are bobbing on the water’s surface, the current, wind and tide ensuring they are never in one spot for long. The males have large, distinctive bills – bright orange and white with a black gonydeal spot. They are breathtaking when they take off and gather momentum; like a wave gathering speed, the air is soon filled with the harmonic whistling of thousands of beating wings.

Jordan says the roe taste sweet and spicy. I eat a chunk of rich and fatty eggs that have fallen off the thick clumps now piled a metre (three feet) high on a blue tarp in the boat. Deep inside the catacomb of eggs I taste hemlock needles. It is the ocean and rainforest in one bite. At first the eggs taste almost acidic or bitter, but then the after-bite kicks in and spicy sweetness emerges. They are almost fruity. The eggs are a delicacy as fine as anything I have ever tried from the ocean.

On shore the intertidal rockweed is exposed and covered with kilometres of shorebirds: black turnstones, spotted sandpipers, surfbirds. Chatting, chirping and low rattling and rasping sounds fill the air as they devour the herring eggs attached to the rockweed. They know the tide is rising and they have only a couple of hours to feed. Well over a thousand eagles can be seen from any vantage point, and there are countless gulls, grebes, loons, ducks, oystercatchers, terns, murrelets, murres, brants, herons, scaups and others – this avian drama is spectacular. For many of these birds this nutritious, predictable and easily accessible food source may mean the difference between nesting success and death, located as it is midway on their 10,000-kilometre (6,000-mile) – or more – migration from their wintering grounds of Mexico and Central America to the open Arctic.

Finally the chatter fades as the birds go off to rest on various islets and in quiet coves, waiting for the next tide. Then the next major event unfolds as the surf scoters come inshore. These black birds with their red, webbed feet can’t go ashore, so they wait for high tide to dive for eggs, preferring the ones attached to eelgrass. I put on my dry suit and underwater gear, dive down about half a kilometre (600 yards) away from them and slowly swim and drift with the current.

Schools of herring flash silver in the milky distance as I settle in about 10 metres (30 feet) of water. Soon the light dims as thousands of surf scoters begin paddling above me. I hold my breath, trying not to laugh at the comical sight. Soon birds are diving down all around me, lunging into the flowing eelgrass headfirst and, with a fast beat of their wings, propelling themselves back toward the surface, long fluorescent-green, egg-encrusted strands of eelgrass trailing in their beaks. They pull the delicate strands of eelgrass off the bottom easily, and it probably digests easily too. Errant strands float gently back down to the ocean bottom. The sheer number of diving birds reduces the sight to bubbles, floating eelgrass and guano, and the flash of black feathers, orange-red feet and bills.

Out of the water, on the next low tide I see a flock of shorebirds lift off suddenly. A pack of six wolves appears from the rainforest edge. They move to the shoreline and with heads down quickly begin to gorge on the herring eggs. Their intensity is born from a long winter in which food is harder to come by. A harbour seal rises through the milt with its face covered in sticky eggs. A mother orca and calf swim through soon afterwards, their backs and dorsal fins covered with a translucent sheen – to be encased in herring eggs must be comforting. For five years in a row the same black bear has shown up along this stretch of spawning ground to eat eggs. Apart from salmon season, this is the only time that wolves and bears predictably show up along the shoreline.

But this is also a coastline of hope because of the passion and determination of British Columbians to protect it. First Nations also continue to choose the environment over promises of short-term wealth offered by the proponents of pipelines and other industrial projects. Most of the hope lies in the fact that this is not a coast that tells the story of loss and what once was. The ecological structure and the species diversity are still here and our job is relatively simple and cost effective: we only have to protect them. We are not in the unenviable and nearly impossible position of having to bring back species and ecosystem function that have been lost. Canada has the longest coastline in the world and has protected less than 1% of our jurisdictional waters. There is plenty of work ahead, but the conservation opportunities for this coast are immense.

Going in for the kill

Like First Nations on this coast, herring have had a troubled relationship with the colonial powers of the past hundred years. The herring have experienced one of the least publicised – yet tragic and unforgivable – examples of government mismanagement of a Pacific coast foundation species.

It’s difficult to understand the Department of Fisheries and Oceans (DFO). Logic would suggest that the agency would support a community-based fishery that is infinitely more sustainable than current ‘kill fisheries’, as they are known, that scoop up thousands of tons of fish just to extract the roe; the rest of the fish ends up as fish meal, cat food or bait. For a fish that can successfully spawn more than 10 times in its life, this is a barbaric end to future spawning options and a sure way to reduce genetic diversity.

The herring kill fishery is an industrial insult to one of the most sensitive and important species in the North Pacific. But this has been the story of overexploiting forage fish for a long time. Sardines were the first to go in the 1940s, and when the nets turned toward herring it took only 20 years for that fishery to collapse too. As soon as the stocks begin to recover, the DFO opens the fishery again. The agency in charge of fisheries management in Canada rarely closes a fishery until the biological extinction of a stock or a species is well under way.

With the herring fishery shut down in Heiltsuk territory, it is blessedly quiet compared to years past, when the arriving seine fleet would also bring Royal Canadian Mounted Police boats to keep the peace between local Heiltsuk protesters and the kill fishers. Perhaps because of this reprieve the stocks are now showing a glimmer of recovery, or at least better returns since the closure.