Predators are thinning out west coast herring, says research | Ha-Shilth-Sa Newspaper

Predators are thinning out west coast herring, says research

Port Alberni, BC

The consumption of herring by marine mammals and fish off the west coast of Vancouver Island is giving the species little chance to rebuild to a higher volume, according to indicators recently presented by a Nuu-chah-nulth-led research project.

The amount being consumed by predators – particularly hake, humpback whales and stellar sea lions – is coming close to what the herring population in Nuu-chah-nulth territory is able to support, said Jim Lane, acting manager of the Uu-a-thluk fisheries program, during a Nuu-chah-nulth Council of Haa’wiih Forum on Fisheries on Feb. 24.

“Predator consumption is almost approaching the total biomass production of WCVI herring,” he said.

Although herring, or ʔaayaaqa in Nuu-chah-nulth, at one time supported a vast commercial fishery in the mid 20th century, in recent decades conservation concerns have led to closures in most parts of the B.C. coast. The commercial catch has for the most part been limited to a fishery opening in the Strait of Georgia for a few weeks each spring, collecting herring with the aim of harvesting females full of eggs before they are released. This valuable roe is mostly sold to markets in Japan, with the actual herring processed into feed for livestock and fish farms.

West of Vancouver Island, stocks have not supported a commercial harvest since 2005. Since then, the herring biomass that has been annually calculated in the region has fluctuated between 5,000 tonnes and over 29,000 - although the overall trend is showing an upward curve for the species. The herring biomass off the west coast of Vancouver Island is projected to be 20,298 tonnes this year, according to Fisheries and Oceans Canada’s current herring management plan.

With harvesting limited to social and ceremonial purposes, the priority in the region has been to allow the species to rebuild, and since 2017 the Nuu-chah-nulth Council of Ha’wiih has agreed to hold off on allowing a commercial catch in its territory until herring show a sustained recovery. What exactly a sustained recovery looks like is still being discussed, although recent correspondence between the Council of Ha’wiih and DFO point to more abundant volumes from the 1990s as a potential target for the species. For most of this period the annual herring biomass west of Vancouver Island was well over 30,000 tonnes.

“[I]t represents herring abundance levels that were able to support successful [food and ceremonial] and [spawn on kelp] fisheries as well as regular commercial seine and gillnet fisheries,” wrote Wickaninnish, Cliff Atleo, chair of the Council of Ha’wiih, in a letter sent to Linda Higgins, the DFO’s area director for B.C.’s south coast.

Sent in November, that letter stresses the importance that “regular commercial seine and gillnet ʔaayaaqa fisheries are not considered until the rebuilding target is achieved” in Nuu-chah-nulth territory.

But new information from an Uu-a-thluk study on herring backed by the B.C. Salmon Restoration and Innovation Fund points to environmental factors that could prevent this rebuilding target from being reached in the foreseeable future. In Lane’s recent presentation to the Council of Ha’wiih hake were identified as the biggest predators of herring on the west coast of Vancouver Island, followed by humpback whales and stellar sea lions.

“The total predation on WCVI herring has gone up exponentially,” said Lane of what he’s seeing each year off the west coast. “It’s around 30,000 tonnes.”

These three top predators are expected to retain strong numbers in the coming years. Russia is a major market for Pacific hake, but since the invasion of Crimea in 2014 Canadian sanctions have blocked exports to the country, leading commercial fishers to often catch short of their quotas.

“Higher hake populations, unless they have a natural decline in the population, are here to stay for a while,” said Lane.

Since they suffered dwindling numbers in the 1960s, the pacific humpback whale population has steadily grown, and is expected to surpass 5,000 in the next two decades. Meanwhile stellar sea lions have increased five-fold since a pinniped hunting ban was imposed in the late 1960s, from under 2,000 to the approximately 10,000 on the west side of Vancouver Island.

The future of the small fish has wide-reaching consequences for the B.C. coast, as herring serve as a keystone species in the ecosystem. Herring account for 32 per cent of the diet consumed by harbour seals, 71 per cent of what lingcod eat, 58 per cent of the diet of coho salmon and 62 per cent of what chinook consume, according to DFO research.

This reliance on the forage fish brings ramifications to the salmon emergency that is currently resounding throughout the West Coast. In February the First Nations Fisheries Council of B.C. announced that “Extinction is not an option” due to the paramount importance of Pacific salmon in the province, and at the recent Council of Ha’wiih forum Tla-o-qui-aht Fisheries Manager Andrew Jackson emphasized that “It’s time for action,” while addressing DFO staff.

As commercial boats anticipate another brief season in the Strait of Georgia, where the biomass is forecasted to be 86,713 tonnes this year, information gathered by the Uu-a-thuk project indicates that herring are not necessarily staying within the five zones currently designated by Fisheries and Oceans Canada. Data collected from decades of tagging the fish from 1937 to 1991 show that approximately 30 per cent leave the west coast of Vancouver Island to populate other areas.

“At some level, they’re all connected to each other,” said Lane. “In order to have healthy herring populations in one area - because there’s contributions and mixing - you’re going to need heathy populations across the range of herring distribution.”


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