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.

Breakthrough allows scientists to determine the age of endangered native fish using DNA


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Benjamin Mayne, CSIROIdentifying the age of animals is fundamental to wildlife management. It helps scientists know if a species is at risk of extinction and the rate at which it reproduces, as well as determining what level of fishing is sustainable.

Determining the age of fish has been difficult in the past — primarily involving extracting the inner ear bone, also known as the “otolith”. Layers of growth in the otolith are counted like rings on a tree to reveal an individual’s age. Unless a dead specimen is available, this method requires killing a fish, making it unsuitable for use on endangered populations.

However a non-lethal DNA test developed by the CSIRO enables researchers to determine fish age for three iconic and threatened Australian freshwater species: the Australian lungfish, the Murray cod and the Mary River cod. We outline the technological breakthrough in our research just published.

Our fast, accurate and cost-effective test can be adapted for other fish species. We now hope to share this method to improve the protection of wild fish populations and help promote sustainable fisheries around the world.

gloved hands cut open fish with sciessors
Traditionally, age could only be determined on a dead fish. The new method is non-lethal.
Shutterstock

Iconic species at risk

Human activity has led to the population declines of the three Australian fish species at the centre of our research.

The threatened Australian lungfish is found in rivers and lakes in southeast Queensland. It’s often referred to as a “living fossil” because its extraordinary evolutionary history stretches back more than 100 million years, before all land animals including dinosaurs.

Man-made barriers in rivers reduce the movement of water, which lowers lungfish breeding rates.

Older lungfish do not have hard otolith structures, which makes determining their age difficult. Bomb radiocarbon, which analyses carbon levels in organic matter, has been used to age Australian lungfish, but this method is too expensive to be widely used.

Australian lungfish
In the past, determining the age of Australian lungfish has been challenging.

The threatened Murray cod is Australia’s largest freshwater fish. The Mary River cod is one of Australia’s most endangered fish, found in less than 30% of its former range in Queensland’s Mary River.

Habitat destruction and overfishing are major threats to Murray cod and Mary River cod populations.

Otoliths can be used to determine age for both these cod species, however this has only been done on a population-wide scale for the more prevalent Murray cod.




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Australia’s smallest fish among 22 at risk of extinction within two decades


Mary River cod
CSIRO estimated the age of Mary River cod.

Our DNA breakthrough

When cells divide to make new cells, DNA is replicated. This can lead to DNA methylation, which involves the addition or the loss of a “methyl group” molecule at places along the DNA strand.

Research has found the level of DNA methylation is a reliable predictor of age, particularly in mammals, including humans.

To develop our test, we first worked with zebrafish. This species is useful when studying fish biology because it has a short lifespan and high reproductive rates. We took zebrafish whose ages were known, then removed a tiny clip of their fin. We then examined DNA methylation levels in the fin sample to identify the fish’s age.

Following this successful step, we transferred the method to Australian lungfish, Murray cod and Mary River cod. Again, we used fish of known ages, as well as bomb radiocarbon dating of scales and ages determined from otoliths.

We found despite the zebrafish and the study fish species being separated by millions of years of evolution, our method worked in all four species. This suggests the test can be used to predict age in many other fish species.




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DNA strand
The test uses co-called DNA methylation to estimate age.
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A conservation management boom?

In the same way human population demographers use census data to understand and model human populations, we now have the tools to do this with animals.

We are looking to expand this DNA-based method to determine the age of the endangered eastern freshwater cod and trout cod. We will also continue to test the method across other species including reptiles and crustaceans.

This work is part of CSIRO’s ongoing efforts to use DNA to measure and monitor the environment. This includes estimating the lifespan of vertebrate species such as long-lived fish and surveying biodiversity in seawater using DNA extracted from the environment.

We envisage that in the not too distant future, these methods may be used by other researchers to better understand and manage wild animal populations.




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The Conversation


Benjamin Mayne, Molecular biologist and bioinformatician, CSIRO

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

New research finds native forest logging did not worsen the Black Summer bushfires


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David Bowman, University of TasmaniaThe Black Summer bushfires shocked the world and generated enormous global media interest. Fire scientists like myself found themselves filling a role not unlike sport commentators, explaining the unfolding drama in real time.

Scientists who engaged with the media during the crisis straddled two competing imperatives. First was their duty to share their knowledge with the community while knowing their understanding is imperfect. Second was the ethical obligation to rigorously test hypotheses against data analysis and peer review – the results of which could only be known long after the fires were out.

One area where this tension emerged was around the influential idea that logging exacerbated the bushfire disaster. During the fire crisis and in the months afterwards, some scientists suggested logging profoundly affected the fires’ severity and frequency. There were associated calls to cease native forestry and shift wood production to plantations.

But there is no scientific consensus about the possible effects of logging on fire risk. In fact, research by myself and colleagues, published in Nature Ecology and Evolution today, shows logging had little if any effect on the Black Summer bushfires. Rather, the disaster’s huge extent and severity were more likely due to unprecedented drought and sustained hot, windy weather.

These findings are significant for several reasons. Getting to the bottom of the bushfires’ cause is essential for sustainable forest management. And, more importantly, our research confirms the devastating role climate change played in the Black Summer fires.

Firefighters recover after battling blazes at Kangaroo Island on 10 January 2019.
David Mariuz/AAP

Looking for patterns

Our research focused on 7 million hectares of mostly eucalyptus forests, from the subtropics to temperate zones, which burned between August 2019 and March 2020.

There is some evidence to suggest logged areas are more flammable that unlogged forests. Proponents of this view say logging regimes make the remaining forests hotter and drier, and leave debris on the ground that increases the fuel load.

In our research, we wanted to determine:

  • the relative roles logging and other factors such as climate played in fires that destroyed or completely scorched forest canopies
  • whether plantations are more vulnerable to canopy scorch than native forests.

To do so, we used landscape ecology techniques that could compare very large areas with different patterns of land use and fire severity. We sampled 32% of the area burnt in three regions spanning the geographic range of the fires.




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firefighters run past fire
The research used landscape ecology techniques to compare large areas.
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What we found

Fire intensity is classified according to the vertical layer of vegetation burnt. A scorched tree canopy suggests the most intense type of fire, where the heat extended from the ground to the treetops.

We found several predictors of canopy damage. First, completely scorched canopy, or canopy consumed by fire, typically occurred across connected swathes of bushland. This most likely reflected instances where the fire made a “run”, driven by localised winds.

Extreme weather fire conditions were the next most important predictor of canopy damage. The drought had created vast areas of tinder-dry forests. Temperatures during the fire season were hot and westerly winds were strong.

Southeast Australia’s climate has changed, making such extreme fire weather more frequent, prolonged and severe.

Logging activity in the last 25 years consistently ranked “low” as a driver of fire severity. This makes sense for several reasons.

As noted above, fire conditions were extraordinarily extreme. And there was mismatch between the massive area burnt and the comparatively small areas commercially logged in the last 25 years (4.5% in eastern Victoria, 5.3% in southern NSW and 7.8% in northern NSW).

Fire severity is also related to landscape features: fire on ridges is generally worse than in sheltered valleys.

Our research also found timber plantations were as prone to severe fire as native forestry areas. In NSW (the worst-affected state) one-quarter of plantations burned – than 70% severely. This counteracts the suggestion using plantations, rather than logging native forest, can avoid purported fire hazards.




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plantation forest divided by road
Plantation forests were found to be highly flammable.
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A challenge awaits

Our findings are deeply concerning. They signal there is no quick fix to the ongoing fire crisis afflicting Australia and other flammable landscapes.

The crisis is being driven by relentless climate change. Terrifyingly, it has the potential to turn forests from critical stores of carbon into volatile sources of carbon emissions released when vegetation burns.

Under a rapidly warming and drying climate, fuel loads are likely to become less important in determining fire extent and severity. This will make it increasingly difficult, if not impossible, to lower fuel loads in a way that will limit bushfire severity.

A massive challenge awaits. We must find socially and environmentally acceptable ways to make forests more resilient to fire while the also produce sustainable timber products, store carbon, provide water and protect biodiversity.

The next step is a real-world evaluation of management options. One idea worth exploring is whether the fire resistance of native forests can be improved in specific areas by altering tree density, vegetation structure or fuel loads, while sustaining biodiversity and amenity.

Commercial forestry could potentially do this, with significant innovation and willingness to let go of current practices.

Through collective effort, I’m confident we can sustainably manage of forests and fire. Our study is but a small step in a much bigger, zig-zagging journey of discovery.




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The Conversation


forest regenerating after fire
Forests must become fire-resilient while performing other functions.
Shutterstock

David Bowman, Professor of Pyrogeography and Fire Science, University of Tasmania

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

Scientists are more likely to study bold and beautiful blooms, but ugly flowers matter too


Myricaria germanica is a rare and endangered species hit hard by climate change, but little research is undertaken to help save it.
Martino Adamo, Author provided

Kingsley Dixon, Curtin UniversityWe all love gardens with beautiful flowers and leafy plants, choosing colourful species to plant in and around our homes. Plant scientists, however, may have fallen for the same trick in what they choose to research.

Our research, published today in Nature Plants, found there’s a clear bias among scientists toward visually striking plants. This means they’re more likely chosen for scientific study and conservation efforts, regardless of their ecological or evolutionary significance.

To our surprise, colour played a major role skewing researcher bias. White, red and pink flowers were more likely to feature in research literature than those with dull, or green and brown flowers. Blue plants — the rarest colour in nature — received most research attention.

But does this bias matter? Plants worldwide are facing mass extinction due to environmental threats such as climate change. Now, more than ever, the human-induced tide of extinction means scientists need to be more fair-handed in ensuring all species have a fighting chance at survival.

Hidden plants in carpets of wildflowers

I was part of an international team that sifted through 280 research papers from 1975 to 2020, and analysed 113 plant species found in the southwestern Alps in Europe.

The Alps is a global biodiversity hotspot and the subject of almost 200 years of intensive plant science. But climate change is now creating hotter conditions, threatening many of its rarest species.

White flower with mountains in background
Edelweiss is a charismatic plant of the Alps that heralds spring.
Shutterstock

Carpeted in snow for much of the year, the brief yet explosive flowering of Europe’s alpine flora following the thaw is a joy to behold. Who was not bewitched when Julie Andrews danced in an alpine meadow in its full spring wildflower livery in The Sound of Music? Or when she sung “edelweiss”, one of the charismatic plants of the Alps that heralds spring?




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Hidden in these carpets of bright blue gentians and Delphiniums, vibrant daisies and orchids, are tiny or dull plants. This includes small sedges (Carex species), lady’s mantle (Alchemilla species) or the snake lily (Fritillaria) with its sanguine drooping flowers on thin stems.

Many of these “uncharismatic plants” are also rare or important ecological species, yet garner little attention from scientists and the public.

Close-up of a blue flower
Bellflowers (Campanula) are conspicuous and prominent in the Alps.
Martino Adamo, Author provided

The plants scientists prefer

The study asked if scientists were impartial to good-looking plants. We tested whether there was a relationship between research focus on plant species and characteristics, such as the colour, shape and prominence of species.

Along with a bias towards colourful flowers, we found accessible and conspicuous flowers were among those most studied (outside of plants required for human food or medicine).

Blue flowers
Bold and beautiful flowers in alpine meadows win scientific attention.
Martino Adamo, Author provided

This includes tall, prominent Delphinium and larkspurs, both well-known garden delights with well-displayed, vibrant flowers that often verge on fluorescent. Stem height also contributed to how readily a plant was researched, as it determines a plant’s ability to stand out among others. This includes tall bellflowers (Campanula species) and orchids.

But interestingly, a plant’s rarity didn’t significantly influence research attention. Charismatic orchids, for example, figured prominently despite rarer, less obvious species growing nearby, such as tiny sedges (Cypreaceae) and grass species.

The consequences of plant favouritism

This bias may steer conservation efforts away from plants that, while less visually pleasing, are more important to the health of the overall ecosystem or in need of urgent conservation.

In this time of urgent conservation, controlling our bias in plant science is critical. While the world list of threatened species (the IUCN RED List) should be the basis for guiding global plant conservation, the practice is often far from science based.

Mat rush with brown flowers
Mat rushes are home for rare native sun moths.
Shutterstock

We often don’t know how important a species is until it’s thoroughly researched, and losing an unnoticed species could mean the loss of a keystone plant.

In Australia, for example, milkweeds (Asclepiadaceae) are an important food source for butterflies and caterpillars, while grassy mat rushes (dull-flowered Lomandra species) are now known to be the home for rare native sun moths. From habitats to food, these plants provide foundational ecological services, yet many milkweed and mat rush species are rare, and largely neglected in conservation research.




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Likewise, we can count on one hand the number of scientists who work on creepy fungal-like organisms called “slime molds”, compared to the platoons of scientists who work on the most glamorous of plants: the orchids.

Yet, slime molds, with their extraordinary ability to live without cell walls and to float their nuclei in a pulsating jelly of cytoplasm, could hold keys to all sorts of remarkable scientific discoveries.

Yellow slime on tree trunk
Slime molds could hold the key to many scientific discoveries, but the organisms are understudied.
Shutterstock

We need to love our boring plants

Our study shows the need to take aesthetic biases more explicitly into consideration in science and in the choice of species studied, for the best conservation and ecological outcomes.

While our study didn’t venture into Australia, the principle holds true: we should be more vigilant in all parts of the conservation process, from the science to listing species for protection under the law. (Attractiveness bias may affect public interest here, too.)

So next time you go for a bushwalk, think about the plants you may have trodden on because they weren’t worth a second glance. They may be important to native insects, improve soil health or critical for a healthy bushland.




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The Conversation


Kingsley Dixon, John Curtin Distinguished Professor, Curtin University

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

Pacific killer whales are dying — new research shows why



A female killer whale leaps from the water in Puget Sound near Seattle.
(AP Photo/Elaine Thompson)

Stephen Raverty, University of British Columbia and Joseph K. Gaydos, University of California, Davis

Killer whales are icons of the northeastern Pacific Ocean. They are intimately associated with the region’s natural history and First Nations communities. They are apex predators, with females living as long as 100 years old, and recognized a sentinels of ecosystem health — and some populations are currently threatened with extinction.

There are three major types of killer whales in the region: the “resident” populations that feed mainly on salmon, the “transients” that prey on other marine mammals like seals and sea lions, and the “offshores” that transit along the continental shelf, eating fish and sharks.

In the 1990s, an abrupt decline in the fish-eating southern resident population dropped to 75 whales from 98, prompting both Canada and the United States to list them as endangered.

A dead killer whale lies on her side in shallow water.
Emaciated female killer whale from Hawaii.
(NOAA/NMFS/PIRO), CC BY

Since then, southern resident killer whales, whose range extends from the waters off the southeast Alaska and the coast of British Columbia to California, have not recovered — only 74 remain today. Because killer whale strandings are rare, scientists have been uncertain about the causes of killer whale mortality and how additional deaths might be prevented in the future.

As a pathologist and wildlife veterinarian, and with the help of countless biologists and veterinarians, we have carried out in-depth investigations into why killer whales in this region strand and died. If we don’t know what is causing killer whale deaths, we are not able to prevent the ones that are human-caused.

We can do better

Human activities have been implicated in the decline and lack of recovery of the southern resident killer whale population, including ship noise and strikes, contaminants, reduced prey abundance and past capture of these animals for aquariums.

Only three per cent and 20 per cent of the northern and southern resident killer whales, respectively, that died between 1925 and 2011 were even found and available for a post-mortem exam. And in most cases, only cursory or incomplete post-mortem exams can be done, generating a limited amount of information.

To figure out why these killer whales are dying — and what it means for the health of individual animals and the population as a whole — we reviewed the post-mortem records of 53 animals that became stranded in the eastern Pacific Ocean and Hawaii between 2004 and 2013. We identified the cause of death in 22 animals, and gained important insight from nine other animals where the cause of death could not be determined.

Human-caused injuries were found in nearly every age group of whales, including adults, sub-adults and calves. Some had ingested fishing hooks, but evidence of blunt-force trauma, consistent with ship and propeller strikes, was more common.

A dead killer whale lies on a beach
The 18-year-old male southern resident killer whale, J34, stranded near Sechelt, B.C., on Dec. 21, 2016. Post-mortem examination suggested he died from trauma consistent with vessel strike.
(Paul Cottrell/Fisheries and Oceans Canada), Author provided

This is the first study to document the lesions and forensic evidence of lethal trauma from ship and propeller strikes.

In recent years governments have focused on limiting vessel noise and disturbance. This study reinforces the need for this, showing that in addition to noise and disturbance, vessel strikes are an important cause of death in killer whales.

Direct human impact

We also developed a body condition index to evaluate the animals’ nutritional health — were they eating enough salmon, for example — to see what role food might play in the sickness and death of stranded animals. Observations of free-ranging killer whales from boats and by unmanned aerial drones have documented sub-optimal body condition or generalized emaciation in many southern resident killer whales.

In this study, we found that longer and therefore older animals tend to have thicker blubber. Our study also found that those animals that died from blunt-force trauma had a better body condition — they were in good health before death. Those that died from infections or nutritional causes were more likely to be in worse body condition.

This new body condition index can help scientists better understand the health of killer whales, and gives us a tool to evaluate their health regardless of their age, reproductive status and health condition.

Our team, working with numerous collaborators including the National Marine Mammal Foundation, is building a health database of the killer whales living in the northeastern Pacific Ocean so that their health can be tracked over time. This centralized database will let stranding response programs, regional and national government agencies and First Nations communities collaborate with field biologists, research scientists and veterinarians.

Ultimately, the information about the health of these killer whales must be conveyed to the public and policy-makers to ensure that the appropriate legislation is enacted to reverse the downward trend in the health and survival of these killer whales. We should now be able to assess future efforts and gain a better understanding of the impact of ongoing human activities, such as fishing, boating and shipping.The Conversation

Stephen Raverty, Adjunct professor, Veterinary Pathology, University of British Columbia and Joseph K. Gaydos, Wildlife Veterinarian and Science Director, The SeaDoc Society, University of California, Davis

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

Scientists at work: Sloshing through marshes to see how birds survive hurricanes



A clapper rail with a fiddler crab in its bill.
Michael Gray, CC BY-ND

Scott Rush, Mississippi State University and Mark Woodrey, Mississippi State University

When storms like Huricane Zeta menace the Gulf Coast, residents know the drill: Board up windows, clear storm drains, gas up the car and stock up on water, batteries and canned goods.

But how does wildlife ride out a hurricane? Animals that live along coastlines have evolved to deal with a world where conditions can change radically. This year, however, the places they inhabit have borne the brunt of 10 named storms, some just a few weeks apart.

As wildlife ecologists, we are interested in how species respond to stresses in their environment. We are currently studying how marsh birds such as clapper rails (Rallus crepitans) have adapted to tropical storms along the Alabama and Mississippi Gulf coast. Understanding how they do this entails wading into marshes and thinking like a small, secretive bird.

Least bittern in marsh grass
A least bittern, one of the smallest species of heron.
Michael Gray, CC BY-ND

Mucky and full of life

Coastal wetlands are critically important ecosystems. They harbor fish, shellfish and wading birds, filter water as it flows through and buffer coastlines against flooding.

You wouldn’t choose a Gulf Coast salt marsh for a casual stroll. There are sharp-pointed plants, such as black needlerush​, and sucking mud. In summer and early fall the marshes are oppressively hot and humid. Bacteria and fungi in the mud break down dead material, generating sulfurous-smelling gases. But once you get used to the conditions, you realize how productive these places are, with a myriad of organisms moving about.

Marsh birds are adept at hiding in dense grasses, so it’s more common to hear them than to see them. That’s why we use a process known as a callback survey to monitor for them.

First we play a prerecorded set of calls to elicit responses from birds in the marsh. Then we determine where we think the birds are calling from and visually estimate the distance from the observer to that spot, often using tools such as laser range finders. We also note the type of ecosystem where we detect the birds – for example, whether they’re in a tidal marsh with emergent vegetation or out in the open on mud flats.

Adult clapper rail calling.

Through this process we’ve been able to estimate the distributions of several species in tidal marshes, including clapper rails, least bitterns (Ixobrychus exilis) and seaside sparrows (Ammospiza maritima). We’ve also plotted trends in their abundance and identified how their numbers can change with characteristics of the marsh.

We’ve walked hundreds of miles through marshes to locate nests and to record data such as nest height, density of surrounding vegetation and proximity to standing water, which provides increased foraging opportunities for rails. Then we revisit the nests to document whether they produce young that hatch and eventually leave. Success isn’t guaranteed: Predators may eat the eggs, or flooding could wash them out of the nest and kill the developing embryos inside.

Salt marshes shelter many types of plants, birds, animals, fish and shellfish.

Rails in the grass

Our research currently focuses on clapper rails, which look like slender chickens with grayish-brown feathers and short tails. Like many other marsh birds, they have longish legs and toes for walking across soft mud, and long bills for probing the marsh surface in search of food. They are found year-round along the Atlantic and Gulf coasts.

Clapper rails typically live in tidal marshes where there is vegetation to hide in and plenty of fiddler crabs, among their frequent foods. Because they are generally common and rely on coastal marshes, they are a good indicator of the health of these coastal areas.

Scientist in marsh holding live Clapper Rail
Ecologist Scott Rush with clapper rail, Pascagoula River Marshes, Mississippi.
Mark Woodrey, CC BY-ND

Water levels in tidal marshes change daily, and clapper rails have some adaptations that help them thrive there. They often build nests in areas with particularly tall vegetation to hide them from predators. And they can raise the height of the nest bowl to protect it against flooding during extra-high or “king” tides and storms. The embryos inside their eggs can survive even if the eggs are submerged for several hours.

When a tropical storm strikes, many factors – including wind speed, flooding and the storm’s position – influence how severely it will affect marsh birds. Typically birds ride out storms by moving to higher areas of the marsh. However, if a storm generates extensive flooding, birds in affected areas may swim or be blown to other locations. We saw this in early June when Hurricane Cristobal blew hundreds of clapper rails onto beaches in parts of coastal Mississippi.

Clapper rails hiding under a breakwater
Clapper rails on a Mississippi beach after Hurricane Cristobal in June 2020.
Mark Woodrey, CC BY-ND

In coastal areas immediately to the east of the eye of a tropical cyclone we typically see a drop in clapper rail populations in the following spring and summer. This happens because the counterclockwise rotation of the storms results in the highest winds and storm surge to the north and east of the eye of the storm.

But typically there’s a strong bout of breeding and a population rebound within a year or so – evidence that these birds are quick to adapt. After Hurricane Katrina devastated the Mississippi Gulf Coast in 2005, however, depending on the type of marsh, it took several years for rail populations to return to their pre-Katrina levels.

Now we’re radio-tagging clapper rails and collecting data that allow us to determine the birds’ life spans. This information helps us estimate when large numbers of birds have died – information that we can correlate with events like coastal hurricanes.

2020 Atlantic hurricane paths
Summary map of the 2020 Atlantic hurricane season, updated Oct. 27.
Master0Garfield/Wikipedia

Losing parts

Tropical storms have shaped coastal ecosystems since long before recorded history. But over the past 150 years humans have complicated the picture. Coastal development – draining marshes, building roads and reinforcing shorelines – is altering natural places that support marsh birds.

Clapper rails and other species have evolved traits that help them offset population losses due to natural disasters. But they can do so only if the ecosystems where they live keep providing them with food, breeding habitat and protection from predators. Coastal development, in combination with rising sea levels and larger tropical storms, can act like a one-two punch, making it increasingly hard for marshes and the species that live in them to recover.

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Biologist Paul Ehrlich has compared species at risk to rivets on an airplane. You might not need every rivet in place for the airplane to fly, but would you fly it through a cyclone if you knew that 10% of its rivets were missing? What about 20%, or 30%? At some point, Ehrlich asserts, nature could lose so many species that it becomes unable to provide valuable services that humans take for granted.

We see coastal marshes as an airplane that humans are piloting through storms. As species and ecosystem services are pummeled, rivets are failing. No one knows where or how the aircraft will land. But we believe that preserving marshes instead of weakening them can improve the chance of a smooth landing.The Conversation

Scott Rush, Assistant Professor of Wildlife Ecology and Management, Mississippi State University and Mark Woodrey, Assistant Research Professor, Mississippi State University

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

Research reveals shocking detail on how Australia’s environmental scientists are being silenced



Authors provided

Don Driscoll, Deakin University; Bob Pressey, James Cook University; Euan Ritchie, Deakin University, and Noel D Preece, James Cook University

Ecologists and conservation experts in government, industry and universities are routinely constrained in communicating scientific evidence on threatened species, mining, logging and other threats to the environment, our new research has found.

Our study, just published, shows how important scientific information about environmental threats often does not reach the public or decision-makers, including government ministers.

In some cases, scientists self-censor information for fear of damaging their careers, losing funding or being misrepresented in the media. In others, senior managers or ministers’ officers prevented researchers from speaking truthfully on scientific matters.

This information blackout, termed “science suppression”, can hide environmentally damaging practices and policies from public scrutiny. The practice is detrimental to both nature and democracy.

A scientist kneels by a stream
When scientists are free to communicate their knowledge, the public is kept informed.
University of Queensland/AAP

Code of silence

Our online survey ran from October 25, 2018, to February 11, 2019. Through advertising and other means, we targeted Australian ecologists, conservation scientists, conservation policy makers and environmental consultants. This included academics, government employees and scientists working for industry such as consultants and non-government organisations.

Some 220 people responded to the survey, comprising:

  • 88 working in universities
  • 79 working in local, state or federal government
  • 47 working in industry, such as environmental consulting and environmental NGOs
  • 6 who could not be classified.

In a series of multiple-choice and open-ended questions, we asked respondents about the prevalence and consequences of suppressing science communication.




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About half (52%) of government respondents, 38% from industry and 9% from universities had been prohibited from communicating scientific information.

Communications via traditional (40%) and social (25%) media were most commonly prohibited across all workplaces. There were also instances of internal communications (15%), conference presentations (11%) and journal papers (5%) being prohibited.

A video explaining the research findings.

‘Ministers are not receiving full information’

Some 75% of respondents reported having refrained from making a contribution to public discussion when given the opportunity – most commonly in traditional media or social media. A small number of respondents self-censored conference presentations (9%) and peer-reviewed papers (7%).

Factors constraining commentary from government respondents included senior management (82%), workplace policy (72%), a minister’s office (63%) and middle management (62%).

Fear of barriers to advancement (49%) and concern about media misrepresentation (49%) also discouraged public communication by government respondents.

Almost 60% of government respondents and 36% of industry respondents reported unduly modified internal communications.

One government respondent said:

Due to ‘risk management’ in the public sector […] ministers are not receiving full information and advice and/or this is being ‘massaged’ by advisors (sic).

University respondents, more than other workplaces, avoided public commentary out of fear of how they would be represented by the media (76%), fear of being drawn beyond their expertise (73%), stress (55%), fear that funding might be affected (53%) and uncertainty about their area of expertise (52%).

One university respondent said:

I proposed an article in The Conversation about the impacts of mining […] The uni I worked at didn’t like the idea as they received funding from (the mining company).

vehicle operating at a coal mine
A university researcher was dissuaded from writing an article for The Conversation on mining.
Dave Hunt/AAP

Critical conservation issues suppressed

Information suppression was most common on the issue of threatened species. Around half of industry and government respondents, and 28% of university respondents, said their commentary on the topic was constrained.

Government respondents also reported being constrained in commenting on logging and climate change.

One government respondent said:

We are often forbidden (from) talking about the true impacts of, say, a threatening process […] especially if the government is doing little to mitigate the threat […] In this way the public often remains ‘in the dark’ about the true state and trends of many species.

University respondents were most commonly constrained in talking about feral animals. A university respondent said:

By being blocked from reporting on the dodgy dealings of my university with regards to my research and its outcomes I feel like I’m not doing my job properly. The university actively avoids any mention of my study species or project due to vested financial interests in some key habitat.

Industry respondents, more than those from other sectors, were constrained in commenting on the impacts of mining, urban development and native vegetation clearing. One industry respondent said:

A project […] clearly had unacceptable impacts on a critically endangered species […] the approvals process ignored these impacts […] Not being able to speak out meant that no one in the process was willing or able to advocate for conservation or make the public aware of the problem.

a dead koala in front of trees
Information suppression on threatened species was common.

The system is broken

Of those respondents who had communicated information publicly, 42% had been harassed or criticised for doing so. Of those, 83% believed the harassers were motivated by political or economic interests.

Some 77 respondents answered a question on whether they had suffered personal consequences as a result of suppressing information. Of these, 18% said they had suffered mental health effects. And 21% reported increased job insecurity, damage to their career, job loss, or had left the field.

One respondent said:

I declared the (action) unsafe to proceed. I was overruled and properties and assets were impacted. I was told to be silent or never have a job again.

Another said:

As a consultant working for companies that damage the environment, you have to believe you are having a positive impact, but after years of observing how broken the system is, not being legally able to speak out becomes harder to deal with.

a scientist tests water
Scientists want to have a positive impact on environmental outcomes.
Elaine Thompson/AP

Change is needed

We acknowledge that we receive grants involving contracts that restrict our academic freedom. And some of us self-censor to avoid risks to grants from government, resulting in personal moral conflict and a less informed public. When starting this research project, one of our colleagues declined to contribute for fear of losing funding and risking employment.

But Australia faces many complex and demanding environmental problems. It’s essential that scientists are free to communicate their knowledge on these issues.




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Public servant codes of conduct should be revised to allow government scientists to speak freely about their research in both a public and private capacity. And government scientists and other staff should report to new, independent state and federal environment authorities, to minimise political and industry interference.

A free flow of information ensures government policy is backed by the best science. Conservation dollars would be more wisely invested, costly mistakes avoided and interventions more effectively targeted.

And importantly, it would help ensure the public is properly informed – a fundamental tenet of a flourishing democracy.The Conversation

Don Driscoll, Professor in Terrestrial Ecology, Deakin University; Bob Pressey, Professor and Program Leader, Conservation Planning, ARC Centre of Excellence for Coral Reef Studies, James Cook University; Euan Ritchie, Associate Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University, and Noel D Preece, Adjunct Asssociate Professor, James Cook University

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

New research reveals how Australia and other nations play politics with World Heritage sites



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Tiffany Morrison, James Cook University; Katrina Brown, University of Exeter; Maria Lemos, University of Michigan, and Neil Adger, University of Exeter

Some places are considered so special they’re valuable to all humanity and must be preserved for future generations. These irreplaceable gems – such as Machu Picchu, Stonehenge, Yosemite National Park and the Great Barrier Reef – are known as World Heritage sites.

When these places are threatened, they can officially be placed on the “List of World Heritage in Danger”. This action brings global attention to the natural or human causes of the threats. It can encourage emergency conservation action and mobilise international assistance.

However, our research released today shows the process of In Danger listings is being manipulated for political gain. National governments and other groups try to keep sites off the list, with strategies such as lobbying, or partial efforts to protect a site. Australian government actions to keep the Great Barrier Reef off the list are a prime example.

These practices are a problem for many reasons – not least because they enable further damage to threatened ecosystems.

Yosemite National Park is on the World Heritage list.
AAP/Kathryn Bermingham

What is the In Danger list?

World Heritage sites represent outstanding socioeconomic, natural and cultural values. Nations vie to have their sites included on the World Heritage list, which can attract tourist dollars and international prestige. In return, the nations are responsible for protecting the sites.

World Heritage sites are protected by an international convention, overseen by the United Nations body UNESCO and its World Heritage Committee. The committee consists of representatives from 21 of the 193 nations signed up to the convention.




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When a site comes under threat, the World Heritage Committee can list the site as in danger of losing its heritage status. In 2014 for example, the committee threatened to list the Great Barrier Reef as In Danger – in part due to a plan to dump dredged sediment from a port development near the reef, as well as poor water quality, climate change and other threats. This listing did not eventuate.

An In Danger listing can attract help to protect a site. For example, the Galápagos Islands were placed on the list in 2007. The World Heritage Fund provided the Ecuadorian government with technical and financial assistance to restore the site’s World Heritage status. The work is not yet complete, but the islands were removed from the In Danger list in 2010.

Ecuador’s Galapagos Islands were removed from the In Danger list in 2010.
EPA

Political games

Our study shows political manipulation appears to be compromising the process that determines if a site is listed as In Danger.

We examined interactions between UNESCO and 102 national governments, from 1972 until 2019. We interviewed experts from the World Heritage Committee, government agencies and elsewhere, and combined this with global site threat data, UNESCO and government records, and economic and governance data.

We found at least 41 World Heritage sites, including the Great Barrier Reef, were at least once considered by the World Heritage Committee for the In Danger list, but weren’t put on it. This is despite these sites being reported by UNESCO as threatened, or more threatened, than those already on the In Danger list. And 27 of the 41 sites were considered for an In Danger listing more than once.

The number of sites on the In Danger list declined by 31.6% between 2001 and 2008, and has plateaued since. By 2019, only 16 of 238 ecosystems were certified as In Danger. In contrast, the number of ecosystems on the World Heritage list has increased steadily over the past 20 years.




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Explainer: what is the List of World Heritage in Danger?


So why is this happening? Our analysis showed the threat of an In Danger listing drives a range of government responses.

This includes governments complying only partially with World Heritage Committee recommendations or making only symbolic commitments. Such “rhetorical” adoption of recommendations has been seen in relation to the Three Parallel Rivers in China’s Yunnan province, the Western Caucasus in Russia and Australia’s Great Barrier Reef (explored in more detail below).

In other cases, threats to a site are high but attract limited attention and effort from either the national government or UNESCO. These sites include Halong Bay in Vietnam and the remote Tubbataha Reefs in the Philippines.

A 2004 amendment to the way the World Heritage Committee assesses In Danger listings means sites can be “considered” for inclusion rather than just listed, retained or removed. This has allowed governments to use delay tactics, such as in the case of Cameroon’s Dja Faunal Reserve. It has been considered for the In Danger list five times since 2011, but never listed.

Threats to Vietnam’s Halong Bay receive little attention.
Richard Vogel/AAP

Case in point: The Great Barrier Reef

In 2014 and 2015, the Australian government spent more than A$400,000 on overseas lobbying trips to keep the Great Barrier Reef off the In Danger list. The environment minister and senior bureaucrats travelled to most of the 21 countries on the committee, plus other nations, to argue against the listing. The mining industry also contributed to the lobbying effort.

The World Heritage Committee had asked Australia to develop a long-term plan to protect the reef. The Australian and Queensland governments appeared to comply, by releasing the Reef 2050 Plan in 2015.

But in 2018, a national audit and Senate inquiry found a substantial portion of finance for the plan was delivered – in a non-competitive and hidden process – to the private Great Barrier Reef Foundation, which had limited capacity and expertise. This casts doubt over whether the aims of the reef plan can be achieved.

Real world damage

Our study makes no recommendation on which World Heritage sites should be listed as In Danger. But it uncovered political manipulation that has real-world consequences. Had the Great Barrier Reef been listed as In Danger, for example, developments potentially harmful to the reef, such as the Adani coal mine, may have struggled to get approval.

Last year, an outlook report gave the reef a “very poor” prognosis and last summer the reef suffered its third mass bleaching in five years. There are grave concerns for the ecosystem’s ability to recover before yet another bleaching event.

Political manipulation of the World Heritage process undermines the usefulness of the In Danger list as a policy tool. Given the global investment in World Heritage over the past 50 years, it is essential to address the hidden threats to good governance and to safeguard all ecosystems.




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The Conversation


Tiffany Morrison, Professorial Research Fellow, ARC Centre of Excellence for Coral Reef Studies, James Cook University; Katrina Brown, Professor of Social Sciences, University of Exeter; Maria Lemos, Professor of Environmental Justice, Environmental Policy and Planning, Climate + Energy,, University of Michigan, and Neil Adger, Professor of Human Geography, University of Exeter

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

Study identifies nine research priorities to better understand NZ’s vast marine area



New Zealand’s coastline spans a distance greater than from the south pole to the north pole.
from http://www.shutterstock.com, CC BY-ND

Rebecca Jarvis, Auckland University of Technology and Tim Young, Auckland University of Technology

The islands of New Zealand are only the visible part of a much larger submerged continent, known as Te Riu a Māui or Zealandia. Most of New Zealand’s sovereign territory, around 96%, is under water – and this means that the health of the ocean is of paramount importance.

Most of the Zealandia continent is under water.
CC BY-SA

New Zealand’s marine and coastal environments have significant ecological, economic, cultural and social value, but they face many threats. Disjointed legislation and considerable knowledge gaps limit our ability to effectively manage marine resources.

With the UN decade of ocean science starting in 2021, it is essential that we meet the challenges ahead. To do so, we have asked the New Zealand marine science community to collectively identify the areas of research we should focus on.

Ten important science questions were identified within nine research areas. The full list of 90 questions can be found in the paper and policy brief, but these are the nine priority areas:




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CC BY-ND

1. Food from the ocean

Fisheries and aquaculture are vital sources of food, income and livelihoods, and it is crucial that we ensure these industries are sustainable. Our study has identified the need for new methods to minimise bycatch, mitigate environmental impacts and better understand the influence of commercial interests in fishers’ ability to adequately conserve and manage marine environments.

2. Biosecurity

The number of marine pests has increased by 10% since 2009, and questions remain around how we can best protect our natural and cultural marine heritage. Future directions include the development of new techniques to improve the early detection of invasive species, and new tools to identify where they came from, and when they arrived in New Zealand waters.

3. Climate change

Climate change already has wide ranging impacts on our coasts and oceans. We need research to better understand how climate change will affect different marine species, how food webs might respond to future change, and how ocean currents around New Zealand might be affected.

Climate change already affects marine species and food webs.
CC BY-ND

4. Marine reserves and protected areas

Marine protected areas are widely recognised as important tools for marine conservation and fisheries management. But less than 1% of New Zealand’s waters is protected to date. Future directions include research to identify where and how we should be implementing more protected areas, whether different models (including protection of customary fisheries and temporary fishing closures) could be as effective, and how we might integrate New Zealand’s marine protection into a wider Pacific network.




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5. Ecosystems and biodiversity

While we know about 15,000 marine species, there may be as many as 65,000 in New Zealand. On average, seven new species are identified every two weeks, and there is much we do not know about our oceans. We need research to understand how we can best identify the current baseline of biodiversity across New Zealand’s different marine habitats, predict marine tipping points and restore degraded ocean floor habitats.

6. Policy and decision making

New Zealand’s policy landscape is complicated, at times contradictory, and we need an approach to marine management that better connects science, decision making and action. We also need to understand how to navigate power in decision making across diverse interests to advance an integrated ocean policy.

7. Marine guardianship

Marine guardianship, or kaitiakitanga, means individual and collective stewardship to protect the environment, while safeguarding marine resources for future generations. Our research found that citizen science can help maximise observations of change and connect New Zealanders with their marine heritage. It can also improve our understanding of how we can achieve a partnership between Western and indigenous science, mātauranga Māori.

8. Coastal and ocean processes

New Zealand’s coasts span a distance greater than from the south pole to the north pole. Erosion and deposition of land-based sediments into our seas has many impacts and affects ocean productivity, habitat structure, nutrient cycling and the composition of the seabed.

Future research should focus on how increased sedimentation affects the behaviour and survival of species at offshore sites and on better methods to measure physical, chemical and biological processes with higher accuracy to understand how long-term changes in the ocean might influence New Zealand’s marine ecosystems.

9. Other anthropogenic factors

Our study identified a range of other human threats that need more focused investigation, including agriculture, forestry mining and urban development.
We need more research into the relative effects of different land-use types on coastal water quality to establishing the combined effects of multiple contaminants (pesticides, pharmaceuticals, etc) on marine organisms and ecosystems. Pollution with microplastics and other marine debris is another major issue.

We hope this horizon scan will drive the development of new research areas, complement ongoing science initiatives, encourage collaboration and guide interdisciplinary teams. The questions the New Zealand marine science community identified as most important will help us fill existing knowledge gaps and make greater contributions to marine science, conservation, sustainable use, policy and management.The Conversation

Rebecca Jarvis, Research Fellow, Auckland University of Technology and Tim Young, Marine Scientist, Auckland University of Technology

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

Dolphin researchers say NZ’s proposed protection plan is flawed and misleading



Hector’s dolphins (Cephalorhynchus hectori) are found only in New Zealand.
Flickr/Scott Thompson, CC BY-ND

Elisabeth Slooten, University of Otago and Steve Dawson, University of Otago

The New Zealand government recently proposed a plan to manage what it considers to be threats to Hector’s dolphins, an endemic species found only in coastal waters. This includes the North Island subspecies Māui dolphin.

Māui dolphins are critically endangered and Hector’s dolphins are endangered. With only an estimated 57 Māui dolphins left, they are literally teetering on the edge of extinction. The population of Hector’s dolphins has declined from 30,000-50,000 to 10,000-15,000 over the past four decades.

The Ministry for Primary Industries (MPI) and the Department of Conservation (DOC) released a discussion document which includes a complex range of options aimed at improving protection.

But the proposals reveal two important issues – flawed science and management.




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Flawed science

Several problems combine to overestimate the importance of disease and underestimate the importance of bycatch in fishing nets. For many years, MPI and the fishing industry have argued that diseases like toxoplasmosis and brucellosis are the main cause of decline in dolphin populations. This is not shared by New Zealand and international experts, who have been highly sceptical of the evidence. Either way, it is not an argument to ignore dolphin deaths in fishing nets.

Three international experts from the US, UK and Canada examined MPI’s work. They concluded that it is not possible to estimate the number of dolphin deaths from disease, much less claim that this impact is more serious than bycatch. On the other hand, it is easy to obtain an accurate estimate of the number of dolphins dying in fishing nets, as long as enough observers are allocated. MPI has failed to do so. Coverage has been so low that MPI’s estimate of catch rates in trawl fisheries is based on one observed capture.

It would be possible to estimate dolphin deaths in trawl nets if enough observers were allocated.
Supplied, CC BY-ND

The MPI model used in the public discussion document (and described in more detail in supporting materials) is complex, and a one-off. It is based on a “habitat model” of dolphin distribution, but fits actual dolphin sightings poorly.

Another problematic aspect of the method is that there is no clear time frame for the “recovery” of dolphin populations to the specified 90% of the unimpacted population size for Hector’s dolphins and 95% for Maui dolphins. This is one of the first things any decision maker would want to know. Would Māui dolphins be held at the current critically endangered population level for another 50 years? If so, this dramatically increases their chance of extinction.

Flawed management options

The second set of problems concerns the management options themselves. These are a complex mix of regulations that differ from one area to another, for gillnets and trawling. They frankly don’t make sense. The International Whaling Commission (IWC) and International Union for Conservation of Nature (IUCN) have recommended banning gillnet and trawl fisheries throughout Māui and Hector’s habitats. MPI’s best option for Māui dolphins comes close to this in the middle of the dolphins’ range, but doesn’t go as far offshore in the southern part of their range.

The South Island options for Hector’s dolphin are much worse. MPI’s approach has been to try to reduce the total number of dolphins killed to just below the level they believe is sustainable. MPI has invented its own method for calculating a sustainable number of dolphin deaths, which is much higher than the well-tested method used in the United States. The next step has been to find areas where the greatest number of deaths can be avoided at the least cost to the fishing industry.

Several Hector’s dolphin populations in the South Island are small, but they act as a bridge between larger populations.
Supplied, CC BY-ND

This sounds reasonable, but fixing the problem only in the places where the largest number of dolphins is being killed will have several negative consequences. Experience shows that fishing effort shifts beyond protected areas, merely moving the problem.

For example, MPI’s proposals leave a large gap on the south and east side of Banks Peninsula, in prime dolphin habitat. If the nearby areas are protected, this gap will be fished, and dolphin bycatch will continue unabated. What’s needed is protection of the areas where dolphins live.

MPI’s focus on reducing the total number of dolphin deaths also ignores the fact that it really matters where those deaths occur. Several Hector’s dolphin populations in the South Island are as small, or smaller, than the Māui dolphin population.

Entanglement deaths have much worse consequences in such small populations, which form a bridge between larger populations. Yet they get no attention in the current options. MPI’s proposals would lead to the depletion of small populations, with increased fragmentation and extinction of local populations.

Only one option

If we want to ensure the long-term survival of these dolphins, there is only one realistic solution: to remove fishing methods that kill dolphins from dolphin habitat. The simple solution is to use only dolphin-safe fishing methods in all waters less than 100 metres deep. This means no gillnets or trawling in harbours and other coastal waters up to the 100 metre depth contour.

There is no need to ban recreational or commercial fishing, but we must make the transition to selective, sustainable fishing methods. These include fish traps, longlines and other hook and line methods. Selective, sustainable fishing methods also use less fuel than trawling and avoid impacts of trawling and gillnets on the broader marine environment.

We also need more observers and more cameras on fishing boats. MPI’s estimate of how many dolphins are dying in fishing nets is almost certainly an under-estimate. It depends heavily on assumptions that are not supported by data.

With observers on only about 2-3% of the inshore fishing boats, the chances of missing bycatch altogether is very high. Low observer coverage also means boats can fish differently on the days when they have an observer aboard (for example, avoiding areas where they have caught dolphins).

Selective fishing methods would protect dolphins and the broader marine environment.
Supplied, CC BY-ND

We know what works

Despite getting a poor report card from the international expert panel, MPI presented a virtually unmodified analysis to the IWC’s scientific committee last month. The committee identified most of the same issues and concluded it needed more time to decide whether MPI’s approach is fit for purpose. Meanwhile the IWC reiterated its recommendation, which it has been making for eight years, to ban gillnets and trawl fisheries throughout Māui dolphin habitat.

In the meantime, dolphins continue to be killed in fishing. We need to make decisions on the basis of scientific evidence available now. All of the population surveys, including those funded by MPI, show Hector’s and Māui dolphins live in waters less than 100 metres deep.

The best evidence of what works comes from Banks Peninsula, where the dolphins have had partial protection since 1988, and detailed follow-up research. This population was declining at 6% per year before gillnets were banned to four nautical miles offshore and trawling to two nautical miles. Even though there was no management of disease, the rate of population decline has dropped dramatically to less than 1% per year. If disease were a serious problem, the restrictions on gillnets would have made little difference.

A general principle in conservation is that the longer you wait, the more difficult and more expensive it will be to save a species, and the more likely we are to fail.The Conversation

Elisabeth Slooten, Professor, University of Otago and Steve Dawson, Professor, University of Otago

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