Why scientists want to clear the air about the role of seals and focus on ecosystemsJENN THORNHILL VERMASPECIAL TO THE GLOBE AND MAILPUBLISHED AUGUST 29, 2021

https://www.theglobeandmail.com/canada/article-scapegoat-or-scoundrel-why-scientists-want-to-clear-the-air-about-the/

Skipper Dwight Russell says there’s “no shortage of seals” in the North Atlantic Ocean, where he and his crew fish off the coast of Labrador. Interviewed in mid-July from his boat, the Miss Mackenzie, he said he and his crew had been surrounded by a herd of harp seals a few days back – an experience he says has become increasingly common.

The sight of all those seals bobbing in the water makes him worry about his fishing prospects – like many fishermen in Newfoundland and Labrador, Skipper Russell believes an “out-of-control” harp seal population has depleted commercial fishing species, leaving little chance of recovery. At the summer shrimp fishery about 80 nautical miles off the eastern tip of Labrador, Fisheries and Oceans Canada (DFO) officials have reported shrimp stock in the “critical zone” for the fifth consecutive year.

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DFO estimates the Northwest Atlantic harp seal population at 7.6 million – the highest on record (based on 2017 data), at more than triple the population of 50 years ago and still steadily increasing.

But Mr. Russell’s concerns are at odds with DFO science, which says the harp seal population is not a major factor in declining fish stocks. Instead, DFO officials offer a different explanation, one that’s harder for local fishermen to accept: that climate change is at the root of the problem. DFO officials held a technical briefing at the end of June to address what they described as “misinformation” about the impacts of seals on fish such as Atlantic cod and capelin in Newfoundland and Labrador waters. During the one-hour briefing, geared toward media, the officials presented the North Atlantic seal as less of a scoundrel and more of a scapegoat.

“People want to understand what is generating the changes in the [fish stock] abundances and why they cannot fish more,” says Dr. Mariano Koen-Alonso, one of the DFO research scientists who presented the June briefing. Certainly, he said, seals provide a convenient explanation for fishing troubles. But if you look more closely at the situation, it “becomes much more complex.”

According to DFO scientists, warmer ocean temperatures and earlier sea-ice melting are among the most worrisome ecosystem changes in the North Atlantic, and that warming trend means poor returns for a variety of fisheries, from capelin to cod to shrimp. As a result, the department is working to shift its “single-species management” model – from fishing and annual catch limits (the primary management tool of fisheries managers considering any fish species in isolation) to “ecosystem-based management,” which takes into account broader variables, such as interactions with other species, the effects of environmental changes, and/or pollution and other stressors on habitat and water quality.The seasonal maximum area of sea ice and the ice season duration on the Newfoundland and Labrador (NL) shelfSince the early 1990s, the severity of sea ice season has gradually decreased, reaching the lowest points in 2011 and 2010. With the exception of a rebound to near-normal values in 2014–2016, sea ice conditions have been weak over recent years. Colder conditions Warmer conditions-2.0-1.5-1.0-0.50.00.51.01.52.02.51969197319771981198519891993199720012005200920132017Shaded areas fallwithin the expectedtemperature range19860.1n/aTHE GLOBE AND MAIL, SOURCE: FRÉDÉRIC CYR, PETER S. GALBRAITH, (2020) NEWFOUNDLAND AND LABRADOR CLIMATE INDEX. FEDERATED RESEARCH DATA REPOSITORY.DATASHARE×

Sea Ice	Colder conditions	Warmer conditions
1969-01-01		-1.04
1970-01-01	0.1
1971-01-01	0.94
1972-01-01	1.89
1973-01-01	1.66
1974-01-01	1.05
1975-01-01	0.62
1976-01-01	0.89
1977-01-01	0.21
1978-01-01		-0.36
1979-01-01	0.1
1980-01-01		-0.25
1981-01-01		-0.55
1982-01-01	0.18
1983-01-01	1.72
1984-01-01	2.26
1985-01-01	1.76
1986-01-01	0.15
1987-01-01	0.3
1988-01-01	0.63
1989-01-01	0.47
1990-01-01	1.48
1991-01-01	1.5
1992-01-01	1.35
1993-01-01	2.15
1994-01-01	1.31
1995-01-01	0.29
1996-01-01	0.06
1997-01-01	0.17
1998-01-01		-0.19
1999-01-01		-0.38
2000-01-01	0.43
2001-01-01		-0.29
2002-01-01		-0.14
2003-01-01		-0.07
2004-01-01		-1.44
2005-01-01		-0.33
2006-01-01		-1.14
2007-01-01		-0.4
2008-01-01	0.46
2009-01-01	0.31
2010-01-01		-1.59
2011-01-01		-1.94
2012-01-01		-0.21
2013-01-01		-0.79
2014-01-01	0.59
2015-01-01	0.36
2016-01-01	0.52
2017-01-01	0.11
2018-01-01		-0.05
2019-01-01		-0.15
2020-01-01		-0.55

THE SEASONAL MAXIMUM AREA OF SEA ICE AND THE ICE SEASON DURATION ON THE NEWFOUNDLAND AND LABRADOR (NL) SHELF

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DFO documentation shows that the department recognized the need to move in this direction in 1998. Twenty years later, in 2019, DFO formally struck a national working group on an ecosystem approach to fisheries management. But so far, their progress remains stalled.

It’s one thing to collect ecological, oceanographic and climate data – an area in which DFO has shown great progress, says Dr. Pierre Pepin, the research scientist who chairs the working group – but it’s quite another to apply that data to fisheries decisions. It’s not yet routine practice to use climate variables in fisheries decisions, says Pepin, because scientists don’t yet know precisely how climate change affects marine species. As a result, even the working group’s best efforts will see DFO continuing to carry out single-species fisheries management, says Pepin. It’s a frustrating situation made even more frustrating by the continued negative attention paid to seals, says Dr. Koen-Alonso, who specializes in ecosystem-based management.

“This is in many ways acting as a distraction from what should be the main conversation, which is how these ecosystems are going to play out as climate conditions change,” says Koen-Alonso of the ongoing preoccupation with seals. “If we want to really rebuild [fish] stocks, we need to understand those things first and use that to guide our management, and not necessarily use our time addressing questions that we know are not going to lead us to a useful, effective answer.”

When it comes to ecosystem changes, warming waters are the key environmental factor DFO cites as affecting Atlantic cod and capelin – both species are critically depleted, compared to historical levels of abundance. While seals are an important predator, they are not an overwhelming one, says Dr. Garry Stenson, a DFO research scientist specializing in marine mammals.

STORY CONTINUES BELOW ADVERTISEMENTThe temperature of the ocean surface (as measured by satellite) on the NL shelfColder than average conditions prevailed in the early 1990s, with 1991 and 1992 being the coldest years. This period was followed by warmer-than-average conditions lasting until about 2014. In recent years, the period 2015–2019 (except for 2016) was colder than normal. The year 2020 was, however, back to above-normal. Colder conditions Warmer conditions-2.0-1.5-1.0-0.50.00.51.01.52.019821985198819911994199720002003200620092012201520181994n/a0.6THE GLOBE AND MAIL, SOURCE: FRÉDÉRIC CYR, PETER S. GALBRAITH, (2020) NEWFOUNDLAND AND LABRADOR CLIMATE INDEX. FEDERATED RESEARCH DATA REPOSITORY.DATASHARE×

SST	Colder conditions	Warmer conditions
1982-01-01	-1.15
1983-01-01	-0.37
1984-01-01	-0.48
1985-01-01	-1.33
1986-01-01	-0.68
1987-01-01	-0.4
1988-01-01		0.03
1989-01-01	-0.71
1990-01-01	-1.1
1991-01-01	-1.94
1992-01-01	-1.96
1993-01-01	-0.72
1994-01-01		0.61
1995-01-01	-0.74
1996-01-01	-0.41
1997-01-01	-0.64
1998-01-01		0.93
1999-01-01		0.89
2000-01-01		0.97
2001-01-01		0.12
2002-01-01	-0.62
2003-01-01		0.6
2004-01-01		0.33
2005-01-01		0.68
2006-01-01		1.36
2007-01-01	-0.11
2008-01-01		0.88
2009-01-01	-0.3
2010-01-01		0.13
2011-01-01		0
2012-01-01		1.51
2013-01-01		0.29
2014-01-01		0.6
2015-01-01	-0.73
2016-01-01	-0.26
2017-01-01	-0.58
2018-01-01	-0.88
2019-01-01	-0.74
2020-01-01		0.73

THE TEMPERATURE OF THE OCEAN SURFACE (AS MEASURED BY SATELLITE) ON THE NL SHELF

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“It would have been simple to answer a question without invoking anything about the environment, but you need to look at the environmental changes that are occurring in order to understand what’s happening to those fish stocks. That’s what’s driving things, not necessarily predation,” says Stenson, who also delivered the June briefing.

It’s not that fishermen need convincing about climate change. Mr. Russell says he’s concerned about weakening sea ice and changing ocean temperature too, particularly what he calls “a warming trend” in the North Atlantic ocean. “The climate is warming up,” he says. “The world’s warming up and the Arctic and Subarctic are warming up at a higher pace than other areas. And I think that’s pretty well reflected [in] what people around Labrador and the coast of Labrador and the fishery see too – it’s quite a warming trend for this year in particular. You just notice certain things, like the lack of icebergs.”The temperature at the ocean floor, as measured in spring and fall on the NL shelfThere was a persistent cold phase from the mid-1980s to the mid-1990s, followed by a warmer phase that peaked in 2011. Shaded areas are considered ‘normal,’ meaning they are within an expected range/show expected fluctuation. Colder conditions Warmer conditions-2.0-1.5-1.0-0.50.00.51.01.52.019801983198619891992199519982001200420072010201320162019-0.2__undefined__THE GLOBE AND MAIL, SOURCE: FRÉDÉRIC CYR, PETER S. GALBRAITH, (2020) NEWFOUNDLAND AND LABRADOR CLIMATE INDEX. FEDERATED RESEARCH DATA REPOSITORY.DATASHARE×

Bottom T	Colder conditions	Warmer conditions
1980-01-01	-0.2
1981-01-01		0.66
1982-01-01	-0.49
1983-01-01	-0.27
1984-01-01	-1.19
1985-01-01	-1.55
1986-01-01	-0.79
1987-01-01	-0.93
1988-01-01	-0.27
1989-01-01	-0.72
1990-01-01	-1.81
1991-01-01	-1.68
1992-01-01	-1.66
1993-01-01	-1.76
1994-01-01	-1.49
1995-01-01	-0.73
1996-01-01	-0.1
1997-01-01	-0.53
1998-01-01		0.3
1999-01-01		1.02
2000-01-01		0.52
2001-01-01	-0.27
2002-01-01	-0.1
2003-01-01	-0.83
2004-01-01		0.77
2005-01-01		0.68
2006-01-01		0.14
2007-01-01		0.02
2008-01-01	-0.07
2009-01-01		0.21
2010-01-01		1.04
2011-01-01		1.82
2012-01-01		0.69
2013-01-01		0.51
2014-01-01	-0.33
2015-01-01	-0.08
2016-01-01		0.36
2017-01-01	-0.49
2018-01-01		0.63
2019-01-01		0.38
2020-01-01		0.63

THE TEMPERATURE AT THE OCEAN FLOOR, AS MEASURED IN SPRING AND FALL ON THE NL SHELF

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More than 100 years of climate data shows the North Atlantic is unquestionably trending warm, especially if you look at bottom temperature (temperature collected at the bottom of the ocean in spring and fall) and sea ice condition trends. The Newfoundland and Labrador Climate Index, which DFO made publicly available in May for the first time, describes the environmental conditions on the NL shelf (the continental shelf extending from Labrador to the east coast of Newfoundland, including the Grand Banks) and in the Northwest Atlantic as a whole. The data shows prevalent sea ice degradation since the early 1990s. The annual number of icebergs is also dramatically increasing – from an annual average of 495 over the last 121 years, to an annual average of 771 over the last thirty years. Meanwhile, the latest assessment report of the Intergovernmental Panel on Climate Change (IPCC), the United Nations body for assessing the science related to climate change, also cued attention to ocean warming and sea ice degradation trends, projected to continue in the Arctic region.