Imagine dragging a massive net weighted with heavy chains across a coral garden. The fragile structures that took centuries to grow shatter in seconds. Fish scatter. The seafloor becomes a graveyard of rubble and broken life. This is bottom trawling, and it happens every day in the deep ocean, often miles beneath the surface where most of us will never see the damage.

But here's the question that keeps marine scientists awake at night: Can these underwater mountains, called seamounts, ever recover? Or are they permanently scarred?

For nearly two decades, researchers in New Zealand have been asking cameras to tell them the answer. What they discovered on a seamount called Morgue offers the first real glimpse of hope and reveals just how complicated ocean recovery truly is.

The Underwater Mountains We're Destroying

Seamounts are essentially underwater mountains that rise from the ocean floor but don't reach the surface. They're far more common than most people realize, dotting ocean floors around the world like hidden peaks in a submerged mountain range.

These aren't barren rock piles. Seamounts teem with life. Their slopes and summits host gardens of cold water corals, swaying sea fans, delicate glass sponges, and countless other creatures. These communities develop over centuries, with some coral colonies living for hundreds or even thousands of years.

The problem? Many seamounts sit at depths between 700 and 1,200 meters, precisely where commercial fishing boats hunt for orange roughy and other deep sea fish. Bottom trawling, the most common method used, involves dragging weighted nets across the seafloor. It's devastatingly effective at catching fish. It's equally effective at destroying everything else in its path.

The corals don't stand a chance. Their skeletons, though hard, are often brittle. A single pass of a trawl net can snap centuries of growth like matchsticks. The nets don't just break the corals; they often rip them completely from the seafloor, leaving fields of rubble behind.

Scientists have documented these impacts for years. But documenting damage is one thing. Understanding whether recovery is even possible is entirely different.

A Seamount Named Morgue

Off the east coast of New Zealand's South Island lies the Chatham Rise, a massive underwater ridge that extends more than 1,000 kilometers into the Pacific. On its northern flank sits a cluster of 28 volcanic seamounts with rather morbid names: Graveyard, Morgue, Zombie, Diabolical, Ghoul, and Gothic.

The names aren't just dramatic. They reflect a grim reality. In the late 1980s and early 1990s, commercial fishing vessels discovered that these seamounts hosted massive aggregations of orange roughy. The trawlers descended in force.

Morgue Seamount, rising about 310 meters from the surrounding seafloor with its summit at 890 meters depth, became a prime target. For roughly a decade, heavy trawl nets scraped across its slopes and summit repeatedly. Then in 2001, something changed. New Zealand designated Morgue as a Seamount Closure Area, prohibiting all bottom trawling from that point forward.

This created an extraordinary natural experiment. Scientists could now ask: What happens to a heavily damaged seamount when the trawling stops?

Twenty Years of Watching and Waiting

Starting in 2001, just as the closure took effect, researchers began visiting Morgue with a towed camera system. They returned in 2006, 2009, 2015, and most recently in 2020. Each time, they photographed the seafloor in exquisite detail, following the same routes as much as possible to capture changes over time.

This kind of patience is rare in science. Most research projects last a few years at most. But deep sea recovery, if it happens at all, unfolds on timescales that dwarf typical research grants and academic careers.

The camera system improved dramatically over the years. The 2001 images were grainy, manually triggered snapshots. By 2020, high resolution cameras captured crystal clear images every 15 seconds, with precise positioning data for every shot. This created a challenge: how do you compare low quality old images with stunning new ones without mistaking technical improvements for actual biological changes?

The research team developed clever solutions. They grouped images into 25 meter grid cells matching the resolution of their seafloor maps. They carefully accounted for differences in image quality and sampling effort. They analyzed nearly 2,000 images in total, documenting every visible creature and carefully tracking changes over time.

What they found wasn't simple. Recovery, it turns out, doesn't follow a straight line.

The Mosaic of Recovery

If you expected a dramatic transformation, like watching a time lapse of a forest regrowing after a fire, you'd be disappointed. Deep sea recovery is subtle, patchy, and frustratingly slow.

But it is happening.

The researchers identified 148 different types of marine life on Morgue between 2001 and 2020. That's remarkable diversity for a supposedly devastated ecosystem. Even more interesting, the communities were changing in ways that suggested movement toward recovery, at least in some areas.

Several key species showed promising trends. Feather stars (comatulids), which look like delicate underwater flowers with feathery arms, initially decreased in abundance between 2001 and 2006, then steadily increased through 2020. Stylasterid hydrocorals, which form intricate branching structures, followed a similar pattern. Both are considered potential early colonizers, species capable of settling and growing relatively quickly by deep sea standards.

The seamount's summit showed the clearest signs of change. Here, the communities became more diverse and complex over time. Species with attached lifestyles and branching body forms became more common, driven largely by those colonizing hydrocorals and bryozoans (tiny colonial animals that form lace-like structures).

But the story varied dramatically across different parts of the seamount. The south slope, which had experienced less intense trawling, showed different patterns than the heavily fished summit. The communities weren't recovering uniformly. Instead, Morgue was becoming a mosaic of different recovery stages, each area responding according to its particular damage history and local conditions.

The Coral Question

Two species held special significance for the researchers: Solenosmilia variabilis and Madrepora oculata. These are reef forming stony corals, the deep sea equivalents of their tropical cousins. They create three dimensional structures that provide homes for countless other species.

These corals were once common across the Graveyard seamounts complex. Bottom trawling devastated them. The question was whether they could ever come back.

The answer appears to be yes, but very, very slowly.

In 2009, eight years after the closure, researchers began spotting tiny coral colonies with just a few polyps each. These weren't remnants of old growth. Based on their size and the known growth rates of these species (somewhere between half a millimeter and 3 millimeters per year), these appeared to be juveniles that had settled after the fishing stopped.

By 2020, the number of images showing these young corals had increased. Their distribution had spread across more of the seamount. This suggests multiple recruitment events, meaning coral larvae from nearby undamaged seamounts had successfully traveled to Morgue, settled on the seafloor, and begun growing.

To put this in perspective, these corals grow so slowly that a colony the size of your fist might be 50 years old. The ones photographed in 2020 probably settled sometime between 2013 and 2018. They won't form substantial reefs for many decades, possibly centuries.

The researchers also found evidence that some corals might be regrowing from fragments that survived the trawling. Small colonies growing among coral rubble suggest that broken pieces, rather than dying completely, might be capable of regenerating.

This dual pathway to recovery (new recruitment plus fragment regeneration) offers more hope than either process alone. But it also underscores just how long full recovery will take.

Why Recovery is So Complicated

Several factors make seamount recovery extraordinarily difficult to predict or accelerate.

First, the creatures that dominate these ecosystems are fundamentally ill-suited to rapid recovery. Deep sea corals grow slowly, live long, and reproduce infrequently. Many don't reach sexual maturity for decades. Their larvae must find suitable settlement sites in a vast, dark ocean, a challenge made harder when most nearby habitat has been destroyed.

Second, the damage isn't limited to the creatures themselves. Trawling physically alters the seafloor, scraping away the complex three dimensional structure that many species need. Coral rubble doesn't provide the same habitat as living coral. Recovery requires not just the return of individual species, but the reconstruction of entire habitat structures.

Third, the patterns researchers observed weren't entirely straightforward. Some species abundances increased between 2009 and 2015, then decreased or plateaued by 2020. This might reflect natural variability in the deep sea environment. The surveys happened during different seasons, and productivity in surface waters (which ultimately feeds the deep sea) varied between years. Alternatively, it might indicate that recovery isn't a smooth progression but rather a series of fluctuations as the ecosystem seeks a new equilibrium.

The researchers also had to consider an uncomfortable possibility: perhaps these communities aren't actually recovering to their original state. They might instead be transitioning to an alternative stable state, a different but persistent community composition. If the current trajectory continues without substantial regrowth of the reef forming corals, Morgue's communities might stabilize into something fundamentally different from what existed before trawling began.

The Management Dilemma

These findings land right in the middle of a heated debate in ocean conservation: Should we protect pristine areas that have never been damaged, or should we also protect damaged areas in hopes they might recover?

For years, many fishing management organizations favored protecting only pristine seamounts. The logic seemed sound: if damaged seamounts can't recover, why waste protection on them? Better to preserve what's still intact and let fishing continue where damage has already occurred.

But this research, along with similar studies from other parts of the Pacific, challenges that assumption. Recovery is possible. It's slow, patchy, and incomplete on the timescales we've observed so far, but it's happening.

This doesn't mean protecting damaged seamounts is always the right choice. But it does mean the decision should be more nuanced. Morgue's relative proximity to undamaged seamounts like Ghoul and Gothic probably helps its recovery, as larvae from healthy coral populations can drift over and settle on Morgue's slopes. A heavily damaged seamount far from any undamaged source populations might have much dimmer recovery prospects.

The research also reveals the critical importance of actually enforcing closures. A few illegal trawls were documented on Morgue even after the 2001 closure. Any additional damage, however minor it might seem, could disrupt or reset the recovery process.

And the closures need to be permanent. Given that full recovery likely requires many decades or even centuries, temporary protected areas accomplish very little. You can't protect a seamount for 10 years, see minimal visible change, declare the effort failed, and reopen it to fishing. The timescales involved require commitments that outlast political administrations, research programs, and individual careers.

What This Means for Ocean Protection

The Morgue Seamount study provides some of the best evidence we have that deep sea ecosystems can begin recovering from bottom trawling damage. But "beginning to recover" is a far cry from "recovered."

After 19 years of protection, Morgue hosts diverse communities with young corals establishing themselves. That's genuinely hopeful. But those communities still reflect the damage history in their structure and function. The reef forming corals remain sparse and small. Full ecosystem recovery will take much longer than humans have yet waited.

This matters far beyond one seamount off New Zealand. Bottom trawling occurs in every ocean. Seamounts worldwide face similar pressures. Understanding whether and how they can recover informs decisions about where to fish, where to establish marine protected areas, and how to balance economic needs against environmental conservation.

The findings suggest that marine protected area networks should ideally include both pristine and damaged sites. The pristine areas preserve biodiversity and serve as source populations for larvae. The damaged areas offer space for recovery and might eventually contribute to regional biodiversity again.

But protection alone isn't enough. We also need realistic expectations about recovery timescales and active monitoring to track whether recovery is actually occurring.

The Long View

There's something both humbling and hopeful about this research. Humbling because it reveals how easily we can damage ecosystems that took millennia to develop, and how difficult they are to repair. Hopeful because it shows that nature, given enough time and freedom from further disturbance, can begin healing even severe wounds.

The creatures returning to Morgue don't know they're part of a scientific study. The tiny coral polyps settling on rubble don't understand they're participants in a grand experiment in ecosystem recovery. They're simply doing what life does: persisting, growing, reproducing, gradually recolonizing available habitat.

That they're succeeding at all, even slowly, suggests that our oceans retain more resilience than we sometimes give them credit for. But that resilience has limits. It operates on timescales measured in human generations, not fiscal quarters or election cycles.

The photographs from Morgue Seamount tell a story about damage and recovery, about patience and persistence. They remind us that the consequences of our actions in the ocean unfold over timeframes we're not accustomed to considering. But they also remind us that those consequences aren't necessarily permanent.

Protection works. Recovery is possible. But both require commitment measured in decades, not years. They require accepting that we might never see the complete results of the protection we put in place today. We're planting trees, as the saying goes, in whose shade we'll never sit.

For the creatures of Morgue Seamount, though, that's exactly what matters. The shade is growing, slowly but surely, one polyp at a time.

Publication Details

Published: April 1, 2025 (online)
Journal: Deep-Sea Research Part I
Publisher: Elsevier Ltd.
DOI: https://doi.org/10.1016/j.dsr.2025.104488

Credit and Disclaimer

This article is based on original research published in Deep-Sea Research Part I by scientists from Victoria University of Wellington, the National Institute of Water and Atmospheric Research (NIWA) in New Zealand, and Newcastle University in the United Kingdom. The content has been adapted for general audiences while preserving complete scientific accuracy. For comprehensive technical details, complete statistical analyses, full methodology, data tables, and supplementary materials, readers are strongly encouraged to consult the original peer-reviewed research article via the DOI link provided above. All scientific findings, conclusions, and data presented here are derived directly from the original publication, and full credit belongs to the research team and their institutions.