The spring hunger of right whales
May 22, 2026
The waters off Casco Bay hold a quiet vastness this morning, the surface barely disturbed by the southwest breeze. Somewhere beyond the islands, in the deeper channels where the continental shelf drops away, the ocean carries a different energy. The water here runs colder and richer than it did a month ago, thick with microscopic life that has traveled north with the warming currents. North Atlantic right whales (Eubalaena glacialis) return to these waters each late spring, following an ancient hunger that pulls them from their calving grounds off Georgia and Florida. They arrive as some of the ocean's most endangered giants, fewer than 340 individuals remaining in the entire North Atlantic. What draws them here is invisible to us but abundant beyond measure: dense swarms of copepods, primarily Calanus finmarchicus, tiny crustaceans no larger than rice grains that drift in massive clouds through the water column. The whales feed by swimming forward with their mouths agape, their baleen plates acting as enormous sieves that strain millions of copepods from each gulp of seawater. A single right whale can consume over a ton of these tiny animals each day, and they must. The females especially arrive here thin from months of nursing calves on milk that contains forty percent fat, their own bodies depleted from the demands of reproduction. The copepods represent more than food; they are survival itself, dense packets of lipids and proteins that will sustain the whales through another year of migration, mating, and the long journey south. The copepods themselves follow rhythms older than the whales. They rise and fall through the water column each day, ascending toward the surface at night to graze on phytoplankton, then sinking to deeper waters as dawn approaches. Their populations peak in these waters during late spring and early summer, timed to the warming temperatures and the spring bloom of microscopic algae. The whales have learned to track these movements, diving to depths where the copepod swarms concentrate most densely. When conditions align, when the currents carry the richest concentrations of prey into the feeding areas, a right whale can meet its daily energy needs in just a few hours of focused feeding. This relationship between whale and copepod plays out against a backdrop of constant change. Warming ocean temperatures shift the timing and location of copepod blooms, sometimes pushing them farther north or deeper than the whales expect. Ship traffic increases through these same feeding areas, bringing noise that can mask the low-frequency calls whales use to communicate across vast distances. Fishing gear poses entanglement risks that have killed more right whales than any other human activity. Yet the whales return each spring, their massive bodies moving through water that holds both abundance and peril in equal measure. If you stand at the edge of Casco Bay this morning and look toward the open Atlantic, the water stretches unbroken to the horizon. The wind carries the salt scent of exposed rockweed and the distant calls of herring gulls. Beneath that surface, in the cold currents that flow past these islands, the ocean's most endangered whale may be feeding on some of its smallest creatures, each mouthful a quiet act of persistence in waters that remember their ancestors.
Basking sharks and the spring bloom
May 21, 2026
The waters off the Maine coast warm slowly through late spring, and with that warming comes an explosion of life invisible from shore. Copepods, tiny crustaceans no larger than rice grains, multiply by the millions in the surface waters. Their numbers peak now, creating dense clouds of protein that drift with the currents. If you are near the water, step closer to the edge. The ocean holds more than it shows. Basking sharks (Cetorhinus maximus) arrive to feed on this bounty. Earth's second-largest fish, they can stretch thirty feet from nose to tail, yet they sustain themselves entirely on these microscopic animals. A basking shark opens its cavernous mouth and swims forward, filtering seawater through gill rakers that trap copepods and other zooplankton. The shark's mouth can expand to nearly three feet across. Water flows in the front and out the gills, leaving behind everything the shark needs. They feed at the surface, their triangular dorsal fins cutting through calm water, sometimes in groups of a dozen or more. The timing matters completely. Copepods reach peak abundance in late spring when water temperatures climb past fifty degrees Fahrenheit and phytoplankton blooms provide abundant food. The microscopic plants multiply first, then the copepods that graze on them, then the basking sharks that follow the copepod concentrations. This cascade happens predictably each year, but the exact timing shifts with water temperature and weather patterns. A cold spring delays everything. An early warm spell accelerates the bloom and brings the sharks sooner. The sharks track their food across hundreds of miles of ocean. Satellite tags show individual sharks moving from wintering grounds off the Carolinas to feeding areas from Cape Cod to the Bay of Fundy, following the zooplankton pulses northward as spring progresses. They filter feed for hours at a time, sometimes diving to depths of three thousand feet between surface feeding sessions. A single shark can filter over a million gallons of water per hour through its gill rakers. The relationship between predator and prey operates on a scale that dwarfs most terrestrial ecosystems, yet depends on organisms so small that thousands fit in a teaspoon of seawater. Listen for the sound of water moving differently, the subtle splash of a large body breaking the surface tension. The dorsal fin appears first, cutting a steady line through the water. Then the snout, broad and blunt. Sometimes the tip of the tail fin shows as the shark feeds just below the surface. The water around a feeding shark often looks different, slightly disturbed, as millions of gallons flow through the animal's mouth and out its gills. Close your eyes if you are near the water now. The spring ocean carries its own rhythm, the sound of abundance feeding abundance in the warming currents offshore.
Common eiders gather in coastal waters
May 20, 2026
The waters off Portland shimmer with late spring light, and if you listen carefully over the sound of small waves against the rocky shore, you might hear the soft conversational murmur of sea ducks riding the swells. Common Eiders (Somateria mollissima) have returned to these Maine waters, their heavy bodies sitting low in the water like dark corks. The males flash white backs and black bellies, while the females wear intricate brown barring that breaks up their silhouette against the waves. These are not passing migrants but homecomers. Common Eiders spend most of their lives at sea, diving for blue mussels, sea urchins, and crabs in depths up to sixty feet. Their bills are perfectly adapted for this work, flattened and broad with sensitive edges that can feel along rocky crevices underwater. What brings them to shore now is the ancient pull of breeding season. Pairs form through elaborate courtship displays where males throw back their heads and call with hollow, musical notes that carry across the water. The female chooses her mate, and together they scout the coastline for nesting sites. Eiders nest on islands and rocky points where land predators cannot easily reach them. The female builds her nest in a shallow scrape, lining it first with seaweed and grass, then with the famous eider down she plucks from her own breast. This down, with its extraordinary insulating properties, will keep her eggs at exactly the right temperature even when she leaves to feed. She incubates alone for nearly a month while her mate returns to sea, often joining bachelor flocks that molt together in late summer. The ducklings hatch covered in dark down and follow their mother to water within hours. They cannot dive yet, so they feed at the surface on small invertebrates and algae until their flight feathers develop. The eiders gathering in these waters now represent a remarkable recovery story. Their populations crashed in the early 1900s due to hunting pressure and egg collection, but protection under the Migratory Bird Treaty Act allowed them to rebound. Still, they face new challenges. Climate change shifts the distribution of their shellfish prey, and rising sea levels threaten low-lying nesting islands. The invasive Common Periwinkle (Littorina littorea) now dominates many intertidal zones where eiders once foraged, creating a less diverse food web. Yet the birds adapt, adjusting their diving patterns and sometimes traveling farther to find the blue mussel beds and urchin populations they depend on. Close your eyes and listen for their voices mixing with the rhythm of water against stone. The sound carries the weight of deep ocean and the lightness of birds coming home to nest, a conversation between sea and shore that has shaped this coast for thousands of springs before this one.
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