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Quieter ships could help Canada’s endangered orcas recover

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Quieter ships could help Canada’s endangered orcas recover

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A female resident orca whale breaches while swimming in Puget Sound in January 2014.
THE CANADIAN PRESS/AP, Elaine Thompson

Priyanka Varkey, Dalhousie University and Tony Robert Walker, Dalhousie University

With the death of the young female orca calf known as J50 in the Pacific Northwest in September 2018, the population of southern resident killer whales has fallen to 74.

At the time, Ken Balcomb, the founder of the Center for Whale Research in Friday Harbor, Wash., said the world was “witnessing a slow motion extinction” of this population of killer whales.

These incredibly low numbers paint an alarming picture for the future of the endangered southern resident killer whales. Experts predict that two more southern resident killer whales will die by this summer due to starvation. Only 40 of the calves born to the southern resident killer whale population have survived since 1998, and 73 have gone missing or found dead. No newborn whales have survived since 2015.

Why are they in such dire straits? The three main stressors for this dwindling population are noise pollution from increased vessel traffic, ocean contaminants and declines in Chinook salmon — the whales’ main source of food.

Research shows that a quieter ocean may help save the southern resident killer whale population, but without regulations yet in place, it may be too little, too late.

Impacts of ship noise

Three groups of orcas — the transient, offshore and resident — live along the Pacific coast. The resident group is further classified into northern and southern populations that have some distribution overlap but do not interbreed. The southern resident population, typically found from southwestern Alaska to central California, is the only orca population in Canada listed as “endangered.”

Underwater ocean ambient noise has increased by approximately 15 decibels in the past 50 years due to increased marine transportation and other anthropogenic (human-made) sources.

Commercial and recreational boats watch orcas in the Salish Sea in British Columbia in July 2015.
(AP Photo/Elaine Thompson)

Noise travels approximately five times faster in water than air and has a wide range of detrimental effects on whales. With increasing numbers of vessels plying the world’s oceans, their engine noise is making it hard for many whale species to communicate.

The documentary “Sonic Sea” likens anthropogenic ambient noise, such as that from vessel engines and drilling for oil or gas, to being trapped in a loud, dark nightclub, unable to see or hear the people right next you. While a human can leave a noisy night club, whales cannot escape these underwater noises.

According to a recent study, the frequency of ship noise overlaps with that of orca communication. It masks noises the orcas make and can interfere with echolocation, which orcas use for navigation and to hunt prey. For the southern resident killer whale population, the limited availability of Chinook salmon combined with vessel noise adds to the challenge of finding food.



Read more:
The Kinder Morgan pipeline and Pacific salmon: Red fish, black gold

The Haro Strait, off the coast of Victoria, is the summer feeding habitat of the southern resident killer whale population. It is also one of the loudest areas along the Pacific coast, especially in the frequency range that orcas use for communication.
As noise from vessels has increased in loudness and now covers a larger geographic area, killer whales have adjusted their vocal communication by increasing the amplitude of their calls to compensate for the underwater noise. But this increased vocal output could have energy costs, cause increased stress or further hinder communication.

Mitigating ship noise

Unlike other forms of marine contamination, noise levels in the ocean can be reduced with relatively small interventions. A recent study investigated ways to reduce vessel noise, and suggested adopting a “multi-pronged approach” to mitigate ocean noise.

The study found that when fast-moving, large vessels reduced their speed to 11.8 knots, the emitted noise dropped by three decibels. This reduction is consistent with precautionary “Okeanos” targets supported by the International Maritime Organization to reduce shipping ocean noise by three decibels within a decade. Shipbuilding industries are already retrofitting noisy ships with quieter engines and designing even quieter ones.



Read more:
The fishy problem of underwater noise pollution

Scientists studying the Haro Strait have suggested using a convoy approach to manage the increasing amounts of ship traffic. Incoming ships would be grouped based on their time of arrival and enter the strait together. Ship noise may increase during the convoy period, but its duration is dramatically reduced. The same study suggested designating B.C.‘s Salish Sea as a Marine Protected Area (MPA) during the summer months to help the southern resident killer whale population recover.

Both Fisheries and Oceans Canada (DFO) and the U.S. National Oceanic and Atmospheric Administration (NOAA) have implemented regulations to mitigate the stress on the orca population. DFO is working with U.S. agencies to coordinate measures to reduce underwater noise impacts on the southern resident killer whales.

A southern resident killer whale breaches near Henry Island in Washington state.
Shutterstock

In 2017, DFO published an action plan to aid in the recovery of the southern resident killer whales, including reduction of underwater noise, limiting disturbance from humans, monitoring whales from a safe distance, ensuring accessible food supply and protecting critical habitat. Recovery plans are legally required for endangered species listed under the Species at Risk Act (SARA), but have been criticized by conservationists for delays in implementation.

In 2018, the government of Canada imposed restrictions on Chinook salmon harvesting with the hope of increasing their availability for the southern resident killer whales.

Washington state Gov. Jay Inslee also launched a task force to create a long-term plan for the recovery and future sustainability of the southern resident killer whales. The recommendations ranged from increasing Chinook salmon availability to a temporary whale-watching moratorium, but they remain a long way from being implemented.

Glimmers of hope

Whale-watching boats and commercial ships are facing an increased number of regulations on how close they can get to orcas in the Salish Sea. As of July 2018, vessels must stay 200 metres away to help limit disturbance of the whales. And in August, Canada’s Federal Court of Appeal rejected the proposed Trans Mountain pipeline expansion, which could result in a seven-fold increase in tanker traffic in the Salish Sea, to 35 vessels a month.

While addressing noise reductions alone is unlikely to be sufficient, it is a necessary first step. The delay in implementation of measures combined with the uncertainty of the effectiveness of implemented measures can make the prospects seem grim for this declining orca population.

However, it is important not to lose hope. There have been recent reports that three females in the southern resident killer whale population are pregnant.

With increased awareness, further action and a $167.4 million investment towards the protection and recovery of endangered whales by the federal government, maybe it’s not too late to save the southern resident killer whales.

Priyanka Varkey, Master’s student, Dalhousie University and Tony Robert Walker, Assistant Professor, Dalhousie University

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

Marine heatwaves are getting hotter, lasting longer and doing more damage

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Marine heatwaves are getting hotter, lasting longer and doing more damage

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Marine heatwaves can kill off species and alter ecosystems.
(Shutterstock)

Eric Oliver, Dalhousie University; Alistair Hobday, CSIRO; Dan Smale, Marine Biological Association; Neil Holbrook, University of Tasmania, and Thomas Wernberg, University of Western Australia

On land, heatwaves can be deadly for humans and wildlife and can devastate crops and forests.

Unusually warm periods can also occur in the ocean. These can last for weeks or months, killing off kelp forests and corals, and producing other significant impacts on marine ecosystems, fishing and aquaculture industries.

Yet until recently, the formation, distribution and frequency of marine heatwaves had received little research attention.

Marine heatwaves occur everywhere in the ocean.
Eric Oliver/Dalhousie University

Long-term change

Climate change is warming ocean waters and causing shifts in the distribution and abundance of seaweeds, corals, fish and other marine species. For example, tropical fish species are now commonly found in Sydney Harbour.



Read more:
On the move: corals migrate south into NSW’s warming waters

But these changes in ocean temperatures are not steady or even, and scientists have lacked the tools to define, synthesize and understand the global patterns of marine heatwaves and their biological impacts.

At a meeting in early 2015, we convened a group of scientists with expertise in atmospheric climatology, oceanography and ecology to form a marine heatwaves working group to develop a definition for the phenomenon: A prolonged period of unusually warm water at a particular location for that time of the year. Importantly, marine heatwaves can occur at any time of the year, summer or winter.

With the definition in hand, we were finally able to analyze historical data to determine patterns in their occurrence.

Analysis of marine heatwave trends

Over the past century, marine heatwaves have become longer and more frequent around the world. The number of marine heatwave days increased by 54 per cent from 1925 to 2016, with an accelerating trend since 1982.

Yearly count of marine heatwave days from 1900 to 2016, as a global average.
Eric Oliver/Dalhousie University

We collated more than 100 years of sea surface temperature data around the world from ship-based measurements, shore station records and satellite observations, and looked for changes in how often marine heatwaves occurred and how long they lasted.

We found that from 1925 to 1954 and 1987 to 2016, the frequency of heatwaves increased 34 per cent and their duration grew by 17 per cent.

These long-term trends can be explained by ongoing increases in ocean temperatures. Given the likelihood of continued ocean surface warming throughout the 21st century, we can expect to see more marine heatwaves globally in the future, with implications for marine biodiversity.

‘The Blob’ effect

Numbers and statistics are informative, but here’s what that means underwater.

A marine ecosystem that had 30 days of extreme heat in the early 20th century might now experience 45 days of extreme heat. That extra exposure can have detrimental effects on the health of the ecosystem and the economic benefits, such as fisheries and aquaculture, derived from it.

A number of recent marine heatwaves have done just that.

In 2011, a marine heatwave off western Australia killed off a kelp forest and replaced it with turf seaweed. The ecosystem shift remained even after water temperatures returned to normal, signalling a long-lasting or maybe even permanent change.



Read more:
A marine heatwave has wiped out a swathe of WA’s undersea kelp forest

That same event led to widespread loss of seagrass meadows from the iconic Shark Bay area, with consequences for biodiversity including increased bacterial blooms, declines in blue crabs, scallops and the health of green turtles, and reductions in the long-term carbon storage of these important habitats.

Similarly, a marine heatwave in the Gulf of Maine disrupted the lucrative lobster fishery in 2012. The warm water in late spring allowed lobsters to move inshore earlier in the year than usual, which led to early landings, and an unexpected and significant price drop.

More recently, a persistent area of warm water in the North Pacific, nicknamed “The Blob”, stayed put for years (2014-2016), and caused fishery closures, mass strandings of marine mammals and harmful algal bloom outbreaks along the coast. It even changed large-scale weather patterns in the Pacific Northwest.

Examples of marine heatwave impacts on ecosystems and species. Coral bleaching and seagrass die-back (top left and right) has affected marine habitats with severe ecological impacts on associated communities. Mass mortality and changes in recruitment patterns of commercially important species such as abalone and lobsters (bottom left and right) have had socio-economic impacts.
Dan Smale/MBA

As global ocean temperatures continue to rise and marine heatwaves become more widespread, the marine ecosystems many rely upon for food, livelihoods and recreation will become increasingly less stable and predictable.

The climate change link

Anthropogenic, that is human-caused, climate change is linked to some of these recent marine heatwaves.

For example, human emissions of greenhouse gases made the 2016 marine heatwave in tropical Australia, which led to massive bleaching of the Great Barrier Reef, 53 times more likely to occur.

Even more dramatically, the 2015-16 marine heatwave in the Tasman Sea that persisted for more than eight months and disrupted Tasmanian fisheries and aquaculture industries was over 300 times more likely, thanks to anthropogenic climate change.

For scientists, the next step is to quantify future changes under different warming scenarios. How much more often will they occur? How much warmer will they be? And how much longer will they last?

Ultimately, scientists should develop forecasts for policy makers, managers and industry that could predict the future impacts of marine heatwaves for weeks or months ahead. Having that information would help fishery managers know when to open or close a fishery, aquaculture businesses to plan harvest dates and conservation managers to implement additional monitoring efforts.

Forecasts can help manage the risks, but in the end, we still need urgent action to curb greenhouse gas emissions and limit global warming. If not, marine ecosystems are set for an ever-increasing hammering from extreme ocean heat.

More information on this and related studies can be found on www.marineheatwaves.org.

Eric Oliver, Assistant Professor, Dalhousie University; Alistair Hobday, Senior Principal Research Scientist – Oceans and Atmosphere, CSIRO; Dan Smale, Research Fellow in Marine Ecology, Marine Biological Association; Neil Holbrook, Professor, University of Tasmania, and Thomas Wernberg, ARC Future Fellow in Marine Ecology, University of Western Australia

This article was originally published on The Conversation. Read the original article.

Dr. Kimberley T A Davies: New fishing rules aim to protect Gulf of St. Lawrence right whales

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New fishing rules aim to protect Gulf of St. Lawrence right whales

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Scientists from the U.S. National Oceanic and Atmospheric Administration approach a young North Atlantic right whale entangled in fishing gear near Cape Canaveral.
(NOAA Photo Library/flickr), CC BY-SA

Kimberley T A Davies, Dalhousie University

Not since the days of whaling had so many North Atlantic right whales died in one year.

In 2017, 17 of the animals died or were entangled live in fishing gear in the Gulf of St. Lawrence, a large region of ocean that borders all five Canadian Atlantic provinces. At the same time, new research showed the population of 458 individuals was in decline — with the females dwindling faster than males.

Scientists became concerned that the North Atlantic right whale might become functionally extinct — unable to produce new calves — in less than two decades.

But these devastating events produced an unexpected silver lining. Researchers, conservationists, industries, managers, policy-makers and public citizens from Canada and the United States rallied in an unprecedented collaborative response to help reduce risk to the remaining animals.

A North Atlantic right whale and her calf, seen in this Feb. 13, 2005 photo.
NOAA, CC BY

This effort culminated in April 2018 with the Canadian government unveiling a number of new management measures for the snow crab and lobster fisheries in the southern Gulf of St. Lawrence.

Some of these measures — including one large closed area, a shorter fishing season in other areas and closures of certain areas if whales are spotted there — are designed to reduce the number of right whale entanglements this year while allowing fishermen to continue to harvest when the whales are less likely to be present.

Additional measures will also help collect improved data on gear deployments so scientists and managers can understand when and where the animals become entangled.

Crustacean cutback

But why did this happen now?

Typically right whales can be found foraging in the Bay of Fundy and southwest Nova Scotia during summer. But since 2010, right whale sightings in traditional foraging grounds have been low. At the same time, reproduction began to decline, culminating in a record low of zero calves born in 2018.

Scientists have shown that variation in both right whale calving rates and their presence in specific areas are related to changes in their primary food source, the infamous copepod Calanus finmarchicus. Armed with the hypothesis that right whales were hungry and searching elsewhere for food, the community of researchers and conservationists began searching other regions where C. finmarchicus is abundant.

One of those areas in the southern Gulf of St. Lawrence proved fruitful, but since right whales had not been observed there often in the past, there were no protections yet in place for them. This exacerbated the events of 2017.

Eating is risky business

Although we almost never witness the death of a right whale, the ones that have been documented and diagnosed tell us that adult right whales die almost exclusively from ship strikes and fishing gear entanglements. Of the conclusively diagnosed mortalities in the Gulf of St. Lawrence, all were attributed to blunt force trauma from being hit by ships or to entanglement.

Marine scientists get a close look at an injured North Atlantic right whale, near Provincetown, Mass., in July 2001. A heavy nylon fishing rope wound around the whale’s upper jaw had caused a serious infection that could eventually lead to the whale’s death.
(AP Photo/Kevin Mingora, Pool)

When right whales forage in the same area as intensive fishing and commercial shipping activities, the risk to the animals can be exceedingly high. The whales spend up to three quarters of their time at or near the surface looking for food or socializing, putting them at risk of ship strikes and entanglement in slack fishing line floating on the ocean surface.

What’s less well-recognized is how much time right whales spend beneath the waves foraging. Their food undergoes vertical migration in the water column and often collects just above the sea floor. This means right whales may also become entangled underwater in the vertical and ground lines that connect several traps along the sea floor to surface buoys.

Mitigation in right whale hot-spots

The best way to prevent entanglement and ship strikes is to reduce the interaction between right whales and fishing gear or vessels. There are a variety of strategies that have been used in Canada and the U.S. to reduce the risk. However, at this time, there is no indication that total mortality in the population is decreasing.

Within a feeding habitat, right whales tend to use similar areas from year to year because these areas have special environmental conditions that result in a plentiful food supply. The government’s decision to close the area where right whales gathered in 2017 to lobster and snow crab fishing means there will be no interaction where right whale densities are likely to be highest.

It’s also possible that the animals may occupy other regions of the southern Gulf, which is a concern because ships and fishing gear may be more concentrated than usual in other areas.

Because of this, fishing will be permitted in other areas unless a right whale is detected, at which time a mandatory dynamic management zone will be enforced for 15 days.

In the Gulf to stay

Historical sightings of right whales in the Gulf of St. Lawrence suggest that the animals have always been present in the area, albeit perhaps in not such noticeably high numbers.

Similarly, historical analyses suggest their food has been present there since at least 1999. But virtually no targeted search effort had been conducted in most areas prior to 2015.

The implication is that the presence of the animals should not be treated as an anomaly. Rather, it is more likely the animals have been using the area unnoticed for some time, and will continue to use the area.

It all means that the fisheries and shipping activities in the region will need to adapt in the long term if we are to have any hope at saving the North Atlantic right whale.

Kimberley T A Davies, Postdoctoral research associate, Dalhousie University

This article was originally published on The Conversation. Read the original article.