Tracking Disrupted Marine Life

by Laura DeMassa ’21

Around March and April of each year, some residents off the Gulf Coast of Florida hear a low drumming throughout their houses. The sound is difficult to locate. Is it coming from inside the house or through the windows? Water pipes are sometimes suspected, but pipes are not to blame for the arrhythmic beating—it’s fish. Hundreds of Black Drum pack together and spawn in nearby canals, and their croaks fill the spring nights.

Before she became a PhD student, Janelle L. Morano worked at Cornell’s Lab of Ornithology, where she listened to fish rather than birds. She tracked species’ movements by deciphering the orchestra of sounds they were making.

“I have taken different paths along the way, but it’s really been always rooted in ecology and trying to understand how animals interact in their environment and with each other,” says Morano, who is advised by Patrick J. Sullivan, Natural Resources and the Environment.

Over the course of the past two decades, scientists have observed dramatic shifts in ocean waters, including temperature, pH, salinity, and ocean circulation patterns. Climate change has strained fish species, which must change their behavior or relocate, or possibly face extinction. Morano is focused on how fish move and migrate in response to climate change, causing fish populations to grow in some areas and dwindle in others.

Where Are the Menhaden Going?

The movement of one fish particularly puzzles Morano: Atlantic Menhaden.

Growing to about a foot long, the silver Menhaden swim in unison within large schools. They sit at one of the bottom rungs of the food chain and have long supported the oldest and largest fisheries along the Atlantic. They are very oily, making them suitable for use as fertilizer, live bait, paint, and ink. Menhaden get their name from Algonquian words: poghaden and munnawhatteaug (“they fertilize”), derived from munnohquohteau (“he enriches the land”).

Menhaden were historically fished all up and down the Eastern Seaboard, but by the 1960s and 1970s their population had drastically contracted. Much of the Menhaden disappeared from the northern Atlantic and could be fished only in the Mid- and South Atlantic. Recently, however, warmer waters have coincided with sightings of Menhaden farther north, off the coast of New York.

“There are questions about what is happening with the population of Menhaden,” Morano says. “In the context of climate change, are they returning to northerly waters and replacing cold water species?”

The potential return of Menhaden to the North Atlantic Coast could pose the risk of disrupting the existing ecosystem. Moreover, the increase in Menhaden off the northern coast has raised concerns about a potential link to recent sightings of dead or gravely injured humpback whales. Since Menhaden are prey for whales, they may have played a part in drawing whales closer to the more dangerous shore.

“There’s no evidence,” Morano says. “It’s all conjecture, but that’s why understanding the distribution of species is important to begin to understand the interaction between predators and prey.”

Her research on the changing distribution of Menhaden could be used to make predictions about the population for a range of possible climate scenarios. Projections such as these would be crucial for commercial fisheries and fishery management councils, which set yearly quotas and caps for fishing.

“Historically, conservation has separated humans from the environment. It was thought that to save the environment you must create pristine spaces.”

Seeking Environmental Justice

In approaching climate change today, Morano does not believe that protecting an environment is best accomplished by walling it off from human activity.

“Historically, conservation has separated humans from the environment. It was thought that to save the environment you must create pristine spaces,” says Morano. As an example, Morano points to the environmentalist movement of the early twentieth century. The movement, led by figures such as John Muir and Theodore Roosevelt, advocated for and established national parks that often displaced Indigenous populations.

“They created a space for wealthy white people and an attitude of ‘I’m going to take this and protect it the way I think is best,’ which ignored, disregarded, and devalued the knowledge that people had and cultural connections to that land, and reimagined it in a privileged white American way,” Morano says.

Morano emphasizes the connections between humans and the natural world. Human society and nature can work in harmony, according to Morano, and she imagines a world in which humans utilize, but do not exhaust, the environment. By studying Menhaden and other fish, Morano illuminates for policymakers how many fish can be caught without detriment to underwater ecosystems.

“There has recently been a shift in conservation writ large that is recognizing how humans are part of conservation,” Morano says. “We have natural resources, and we need to think about how humans use the environment. Also, not all humans use the environment in the same ways. In the past, we have cut out people, including Indigenous communities, from how they use the environment. We need to shift our perspective, acknowledge the damage wrought by colonialism and conservation practices, and change them. This is really critical for adapting to climate change in a just and equitable way.”