Giant sea bass are thriving in Mexican waters – scientific research that found them to be critically endangered stopped at the US-Mexico border

Giant sea bass are listed as a critically endangered species.
Maru Brito, CC BY-ND

Arturo Ramírez-Valdez, University of California San DiegoI was looking at the seafloor, focused on identifying fish species as I normally did when diving off of the California coast, when suddenly I felt something large above me. When I turned my head I saw a giant fish – more than 6 feet (2 meters) long – calmly interested in the air bubbles coming from my SCUBA regulator. This was 2016 and was my first encounter with a giant sea bass.

I am a marine ecologist, and I study how international borders pose challenges for conservation and management efforts in the marine environment. Although there are no walls or fences in the ocean, borders still act as stark barriers for a variety of things.

Giant sea bass live off the west coast of North America in both Mexican and U.S. waters. I have found that large differences in regulation and research effort between the two countries has led to a significant misunderstanding of giant sea bass population health.

A map showing high density of giant sea bass along the west coast of the U.S. and along both sides of the Baja Peninsula. — Giant sea bass live in coastal waters from northern California all the way south to the Sea of Cortez.
Arturo Ramiréz-Valdez, CC BY-ND

Different countries, different science

The giant sea bass is the largest coastal bony fish in the Northeastern Pacific. It can grow up to 9 feet (2.7 meters) long and weigh up to 700 pounds (315 kg). It lives in coastal waters from northern California to the tip of the Baja California peninsula in Mexico, including the entire Gulf of California.

In California, commercial fishing for the species began in the late 1880s. Large fish used to be very abundant across the entire range, but the fishery collapsed in the early 1970s. As a response, in 1981 the U.S. banned both commercial and recreational fishing for giant sea bass, and there are many ongoing research and population recovery efforts today.

The collapse and subsequent protection and flurry of research in the U.S. stand in stark contrast to Mexico. In Mexico, there are minimal regulations on fishing for the species, and there is almost a complete lack of data and research on it – there are only three studies on giant sea bass with any data from Mexico.

The International Union for Conservation of Nature considers giant sea bass to be a critically endangered species due to the population being “severely fragmented, leading to a continuing decline of mature individuals.” But this decision was based on a report that had no data whatsoever from Mexico. This lack of data is concerning, considering 73% of the species’ range is in Mexican waters.

This knowledge gap made me wonder if ecologists had the wrong idea about the health of giant sea bass populations.

A man standing behind a very large black fish on a scale. — Giant sea bass are a common sight at fish markets throughout Baja.
Proyecto Mero Gigante, CC BY-ND

Healthy fish in Mexico

In 2017, I led an effort to document the giant sea bass population in Mexico and look for clues to what it was in the past. At the beginning of the project, my colleagues and I feared that the records in Mexico would confirm the precarious situation of the fish in the U.S. But the reality turned out to be the opposite.

A man in orange overalls on a small blue boat sitting behind four large black fish on the deck. — Commercial fishers don’t often target giant sea bass, but catch them as bycatch when fishing for other species.
Proyecto Mero Gigante, CC BY-ND

To our surprise, we found giant sea bass everywhere in the fish markets and fishing grounds from our very first assessments. The fishmongers were never out of the fish; instead, they would ask us, “How many kilos do you need?” It was clear that for fishers in Mexico, the species is still common in the sea, and therefore, in their nets. It is still possible to find big fish up to 450 pounds 200 kilograms, and the average catch was around 26 pounds (12 kilograms).

It was fantastic to see an abundance of these fish in markets, but I also wanted to understand the fishery trends through history and how current fishing levels compared to previous years. I looked at historical and contemporary fishing records and found that the Mexican commercial fleet has caught an average of 55 tons per year over the past 60 years, and the fishery has been relatively stable over the past 20 years, with a peak in 2015 at 112 tons.

According to U.S. and Mexican records, the largest yearly catch ever recorded for giant sea bass in Mexico was 386 tons in 1933. Biologists consider a fishery to have collapsed when total catches, under the same effort, are less than 10% of the largest catches on record. So a steady trend of 55 tons per year shows that the fishery in Mexico has not collapsed. It is clear that giant sea bass populations have faced severe declines throughout their range; however, the health of the species is not as dire as thought.

Another interesting finding from my research is that the apparent collapse of the giant sea bass fishery documented in the 1970s actually began as early as 1932.

Over the first half of the 20th century, as the U.S. commercial fleet overfished U.S. waters, they began fishing in Mexican waters too – but they continued to count all catches as from the U.S. This changed in 1968 when the two governments signed the Mexico–U.S. Fisheries Agreement, limiting how much fish each country’s fleet could take from the other country’s waters. The collapse of the U.S. fishery in the 1970s was not due to a drastic reduction in fish numbers in Mexican waters, but driven by changes in fishing regulation between the U.S. and Mexico. The California fish populations had been depressed for decades, but this was hidden by fish from Mexico.

A large dark fish swimming in a kelp forest and surrounded by smaller fish. — Giant sea bass populations in Mexico have declined, but are still much healthier than researchers thought.
Meru Brito, CC BY-ND

Better data, better management

Based on my research, I believe that the giant sea bass may not qualify as a critically endangered species. My analysis of modern catch data suggests that the population of this iconic fish is likely much larger than biologists previously thought, especially in Mexico.

I am leading the next assessment for the International Union for Conservation of Nature, and now that we have accumulated better data, we can make a more informed decision that balances responsible management of the species with human needs.

I hope that our study inspires policymakers in the U.S. and Baja to start a conversation about how to manage this incredible fish in a collaborative way. But I feel our work also has larger implications. It shows how asymmetry in research and data can create significant barriers to understanding the past and present status of a species like the giant sea bass and make it harder to implement sustainable practices for the future.

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Arturo Ramírez-Valdez, Researcher, University of California San Diego

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Monarch butterflies’ spectacular migration is at risk – an ambitious new plan aims to help save it

Monarch butterflies cover a tree at El Rosario Monarch Butterfly Sanctuary in Michoacán, Mexico.
D. André Green II, CC BY-ND

D. André Green II, University of Michigan

One of nature’s epic events is underway: Monarch butterflies’ fall migration. Departing from all across the United States and Canada, the butterflies travel up to 2,500 miles to cluster at the same locations in Mexico or along the Pacific Coast where their great-grandparents spent the previous winter.

Human activities have an outsized impact on monarchs’ ability to migrate yearly to these specific sites. Development, agriculture and logging have reduced monarch habitat. Climate change, drought and pesticide use also reduce the number of butterflies that complete the journey.

Map of North America showing monarch migration routes. — Monarch butterflies migrate south in fall and north in spring, traveling up to 2,500 miles.
MonarchWatch.org, CC BY-ND

Since 1993, the area of forest covered by monarchs at their overwintering sites in Mexico has fallen from a peak of 45 acres in 1996-1997 to as low as 1.66 acres in the winter of 2013-2014. A 2016 study warned that monarchs were dangerously close to a predicted “point of no return.” The 2019 count of monarchs in California was the lowest ever recorded for that group.

What was largely a bottom-up, citizen-powered effort to save the struggling monarch butterfly migration has shifted toward a top-down conversation between the federal government, private industry and large-tract landowners. As a biologist studying monarchs to understand the molecular and genetic aspects of migration, I believe this experiment has high stakes for monarchs and other imperiled species.

Millions of people care about monarchs

I will never forget the sights and sounds the first time I visited monarchs’ overwintering sites in Mexico. Our guide pointed in the distance to what looked like hanging branches covered with dead leaves. But then I saw the leaves flash orange every so often, revealing what were actually thousands of tightly packed butterflies. The monarchs made their most striking sounds in the Sun, when they burst from the trees in massive fluttering plumes or landed on the ground in the tussle of mating.

Decades of educational outreach by teachers, researchers and hobbyists has cultivated a generation of monarch admirers who want to help preserve this phenomenon. This global network has helped restore not only monarchs’ summer breeding habitat by planting milkweed, but also general pollinator habitat by planting nectaring flowers across North America.

A monarch butterfly in a Toronto park on common milkweed, an important plant for its survival.
Colin McConnell/Toronto Star via Getty Images

Scientists have calculated that restoring the monarch population to a stable level of about 120 million butterflies will require planting 1.6 billion new milkweed stems. And they need them fast. This is too large a target to achieve through grassroots efforts alone. A new plan, announced in the spring of 2020, is designed to help fill the gap.

Pros and cons of regulation

The top-down strategy for saving monarchs gained energy in 2014, when the U.S. Fish and Wildlife Service proposed listing them as threatened under the Endangered Species Act. A decision is expected in December 2020.

Listing a species as endangered or threatened triggers restrictions on “taking” (hunting, collecting or killing), transporting or selling it, and on activities that negatively affect its habitat. Listing monarchs would impose restrictions on landowners in areas where monarchs are found, over vast swaths of land in the U.S.

In my opinion, this is not a reason to avoid a listing. However, a “threatened” listing might inadvertently threaten one of the best conservation tools that we have: public education.

It would severely restrict common practices, such as rearing monarchs in classrooms and back yards, as well as scientific research. Anyone who wants to take monarchs and milkweed for these purposes would have to apply for special permits. But these efforts have had a multigenerational educational impact, and they should be protected. Few public campaigns have been more successful at raising awareness of conservation issues.

University of Michigan biologist D. Andre Green studies monarch butterflies’ DNA to understand what drives their incredible migration.

The rescue attempt

To preempt the need for this kind of regulation, the U.S. Fish and Wildlife Service approved a Nationwide Candidate Conservation Agreement for Monarch Butterflies. Under this plan, “rights-of-way” landowners – energy and transportation companies and private owners – commit to restoring and creating millions of acres of pollinator habitat that have been decimated by land development and herbicide use in the past half-century.

The agreement was spearheaded by the Rights-of-Way Habitat Working Group, a collaboration between the University of Illinois Chicago’s Energy Resources Center, the Fish and Wildlife Service and over 40 organizations from the energy and transportation sectors. These sectors control “rights-of-way” corridors such as lands near power lines, oil pipelines, railroad tracks and interstates, all valuable to monarch habitat restoration.

Under the plan, partners voluntarily agree to commit a percentage of their land to host protected monarch habitat. In exchange, general operations on their land that might directly harm monarchs or destroy milkweed will not be subject to the enhanced regulation of the Endangered Species Act – protection that would last for 25 years if monarchs are listed as threatened. The agreement is expected to create up to 2.3 million acres of new protected habitat, which ideally would avoid the need for a “threatened” listing.

Many questions remain. Scientists are still learning about factors that cause monarch population decline, so it is likely that land management goals will need to change over the course of the agreement, and partner organizations will have to adjust to those changes.

Oversight of the plan will fall primarily to the University of Illinois, and ultimately to the U.S. Fish & Wildlife Service. But it’s not clear whether they will have the resources they need. And without effective oversight, the plan could allow parties to carry out destructive land management practices that would otherwise be barred under an Endangered Species Act listing.

A model for collaboration

This agreement could be one of the few specific interventions that is big enough to allow researchers to quantify its impact on the size of the monarch population. Even if the agreement produces only 20% of its 2.3 million acre goal, this would still yield nearly half a million acres of new protected habitat. This would provide a powerful test of the role of declining breeding and nectaring habitat compared to other challenges to monarchs, such as climate change or pollution.

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Scientists hope that data from this agreement will be made publicly available, like projects in the Monarch Conservation Database, which has tracked smaller on-the-ground conservation efforts since 2014. With this information we can continue to develop powerful new models with better accuracy for determining how different habitat factors, such as the number of milkweed stems or nectaring flowers on a landscape scale, affect the monarch population.

North America’s monarch butterfly migration is one of the most awe-inspiring feats in the natural world. If this rescue plan succeeds, it could become a model for bridging different interests to achieve a common conservation goal.

D. André Green II, Assistant Professor of Ecology and Evolutionary Biology, University of Michigan

This article is republished from The Conversation under a Creative Commons license. Read the original article.