Salmon sharks are high on the list of possible predators that might be chewing into sockeye salmon numbers

Sharks among culprits eyed at sockeye inquiry

No single predator likely to blame for salmon demise: report

Predators from seabirds to sharks may be helping gobble up the Fraser River’s declining sockeye salmon.

A new study tabled with the Cohen Commission concludes there’s no evidence any single predator can be blamed for the sockeye collapse.

But collectively they may be hurting stocks, especially when considered in concert with other threats.

“There is no sign of a smoking gun among the long list of potential predators of Fraser River sockeye salmon,” according to the technical report by UBC researchers.

“Instead, predation is more likely to be part of the cumulative threats that sockeye contend with.”

Salmon sharks, blue sharks and an obscure species called daggertooth are thought to have increased in number in the ocean off B.C., where they are target migrating sockeye.

Salmon sharks – which grow up to 2.6 metres and 220 kilograms – are among the likeliest suspected sockeye predators from a list of 26 species considered, Dr. Villy Christensen told the inquiry earlier this month.

An estimated 10,000 sharks may lurk in a “hot zone” in Queen Charlotte Sound near the southern tip of Haida Gwaii on the migration path of Fraser sockeye, the inquiry heard.

Death may also come from above – Caspian terns and double-crested cormorants feast on sockeye smolts in freshwater and those seabirds may be increasing in number.

Other prime suspects include the lamprey, blood-sucking eels that attack in the Fraser River and its estuary.

Various other salmon, trout and perch species can also eat juvenile sockeye in freshwater.

Sablefish, arrowtooth flounder and Humboldt squid also target sockeye, according to the study.

The researchers note once-abundant prey species like walleye pollock, Pacific cod, mackerel and hake have all declined and that may be forcing larger predators to eat more sockeye than before.

Seals, sea lions, killer whales and dolphins also eat sockeye, but the findings did not point to any of the marine mammals as a significant culprit.

Seals were once regularly culled or hunted but their populations have soared 10-fold since that practice ended in 1970.

The inquiry heard evidence that past culls of seals or sea lions have not necessarily succeeded in preserving salmon and can have unpredictable consequences.

A separate study commissioned by the inquiry looked at contaminants in the Fraser River from pulp mills, sewage discharges and other sources in the watershed.

More than 200 chemicals of concern were detected that may harm salmon in the river.

Selenium and dioxin-type compounds were found in salmon eggs at high levels likely to affect sockeye reproduction, the report found.

Elevated levels of metals and phenols were also found at several locations in the river, but were not likely to harm sockeye salmon.

The report concludes contaminant exposure did not likely trigger the collapse in sockeye numbers over the past 20 years, but may have contributed to the decline.

The Cohen commission was named after the collapse of the 2009 sockeye run, when just over a million fish returned, about a tenth the expected number. A huge return last year is thought by many experts to be an anomaly in a long-term decline.

Just Posted

Agassiz Community Health Centre welcomes its newest doctor

Nikki Cohen is one of three doctors practicing at the local health clinic

No home for Agassiz Community Garden on school district land

The garden is still homeless after SD78 said no to the society using the McCaffrey School property

Chilliwack school board making effort to foster better relationships

Board reaching out to parents via dinner event, and online forum

PHOTO: Pollination time

Hyacinths attract bees looking for pollen

Sardis Library hosting Star Wars-themed escape room

Participants asked to summon the force for week-long attraction

VIDEO: Agassiz, Harrison celebrate National Pet Day

From cats and dogs to lizards and chickens, residents showed off the animals that enrich their lives

PHOTOS: Green Party Leader Elizabeth May says ‘I do’ on Earth Day

May and John Kidder got married Monday morning in Victoria

Victims injured in Lower Mainland deck collapse ranged from 15 to 83 years old

Victim Services staff have reached out to those hurt and their families

‘Ghost restaurants’ cooked up by Joseph Richard Group to meet demand of delivered food

The new Meal Ticket Brands venture aims to ‘disrupt’ the local restaurant industry

Sri Lanka invokes war-time military powers after nearly 300 killed in Easter bombings

Sri Lanka’s minister of tourism says 39 foreign tourists were killed in the Easter Sunday attacks

Torched SUV linked to Vancouver’s fourth homicide

Manoj Kumar, 30, was found dead from gunshot wounds in the Kitsilano neighbourhood

Multiple sailing waits as BC Ferries deals with Easter Monday traffic

89 extra sailings had been added to the long weekend schedule

Ex-mayor of northern village claims its drivers are overpaying ICBC $1,800 a year

Darcy Repen says data shows Telkwa households are being ripped off for car insurance

Deadly synthetic drug found in Kamloops that puts users in ‘zombielike’ state

Interior Health warning says substance causes ‘speedy, trippy-like symptoms’ and hallucinations

Most Read