What causes dead herring by the hundreds

[MGH]

In December came across this scene ( attached photo) of dead Herring floating just outside Toquart Bay.
The pictures don't show the extent of the dead as cell phone camera is limited and when we came across this some were still coming to the surface and birds, Sea Lions, Seals were having a feast, and we came across 3 Killer Whales later that could have been in area. The swath of dead was about a Kilometer long and 40 meters wide. And yes we did fill a pail with Herring. Just scoped them up with Salmon net.
Friend just figured out how to send pictures from his camera.
Weather was cold at the time. Day before there was ice on the water that made a horrible sound when the aluminum boat passed through it.
Any ideas or experiences that would indicate what caused this.
Is this a natural occurrence.

Mike H

 

[MGH]

Did something wrong with photos.

Fixed, thats better

 

[King_Cod]

Wow that is a lot of dead Herring!

 

[Lipripper]

Spawn death? Not too sure but they don't always live after spawning???

 

[MGH]

I didn't think they spawned until March or April.

 

[Haze]

I think there has now been several different sightings of dead herring like this. If I were to guess (and this may be a long shot) I would say that it probably has to do with the big oil spill the US was having earlier. The chemicals they used to eat/destroy the oil were actually worse for some marine life than the oil. Since patches of dead herring have popped up liked this, that would be my best "try to explain this guess."

 

[MGH]

Wonder what effect that would have on the Sea gulls, ducks, Eagles, seals, whales and even the fish that would have eat them when they sank. Didn't see any other dead creatures around. The way the herring were on the surface looked like a boat had gone through the area chumming something deadly.
Could being pushed up through the cold upper layer of water kill them. ( whales pushing up herring ball.)

 

[yammy5]

Did you guys contact DFO with this information when the event occurred? I would encourage you to do that in the future if you didn't as they would be the best ones to provide an explanation or conduct an investigation. Herring and water samples could have been collected for analysis. DFO also monitors plankton and algae blooms with Satellite technology which could provide some information on the event. It is perhaps possible that this event could also affect (kill) juvenile salmon so the results of an investigation could provide a piece of the puzzle in determining ocean events that affect salmon populations. DFO Observe, Record and Report # 1-800-465-4336

 

[MGH]

That area is a dead zone for my cell phone so we were going to call after pulling prawn traps but on returning there was not fish in sight. no sigh of anything. You are right we should have called!!

 

[victoriaboater]

Call DFO and let them know. Late is better than never. They should be able to predict water movement and what was going on at the time and where things have ended up. Just guessing this was Saanich inlet by the photos. My guess is illegally caught fish dumped overboard.

 

[MGH]

This area is just above Stopper Island going into Mayne bay. Near Toquart bay, Broken Island group (Ucluelet)

 

[yammy5]

I emailed the experts at DFO Nanaimo (Pacific Biological Station) and they were not aware of this event. These events are apparently uncommon with herring, but several others occurred in January in the Strait of Georgia this year. They would be very interested in receiving this information immediately if any such event is witnessed again. They can perform tests on 'fresh' samples to determine if disease was a factor. There are natural diseases that can cause this (e.g., viral hemorrhagic septicemia VHS). They mentioned that these large die-off events are more common (almost yearly) with sardines and are caused by cold water incursions. If anyone witnesses such an event they request that the herring be kept on ice if possible and delivered to the Pacific Biological Station in Nanaimo. Freezing them would be the second best option.

Do you still have the frozen herring from this event? They would like to take a look at them to see if they can perform some virology tests.

 

[yammy5]

Here is the article regarding the Strait of Georgia herring die-off:

Dead herring mystery remains unsolved
Robert Barron
The Daily News


Monday, February 28, 2011


There's still no "smoking gun" pointing to the cause of the thousands of dead herring that washed ashore on beaches in Cedar last month, according to Brenda Spence, a spokeswoman for the department of Fisheries and Oceans Canada.

Spence said test results of the herring that were sent to DFO labs for analysis to determine if disease and/or contaminants in the water played a part in their demise came back inconclusive.

She said the investigation into the incidents is now in the hands of fisheries officers who are looking at the possibility that the dead fish came from boats taking part in the small food and bait herring fishery that was underway in the Strait of Georgia at the time.

"We're looking at the loss of herring nets from some of those boats as a source," Spence said.

Thousands of dead herring washed ashore on a beach north of Boat Harbour and nearby Cedar-by-the-sea over a three-day period in January.

DFO conducted tests for disease, because there are some diseases endemic to herring that can cause large die-offs of this nature, as well as toxicology tests to see if there was anything in the water, but suspicions arose early that both incidents were likely the result of sea lions eating through nets used in the food and bait herring fishery, which was reported to DFO by boats operating in the Cedar area at the time.

However, fisheries officer Linda Higgins, who is now heading the investigation, said it's "still too early" to definitely determine the cause of the dead fish.

She said if the herring boats in question are found to have violated fishery regulations and caused the incidents, it's possible that charges could be laid.

"We're still gathering information at this time," Higgins said.

Despite the large number of herring that washed ashore, DFO officials don't believe at this stage of their investigation that the incidents have any "biological significance" on the herring stocks in the strait.

The annual herring fishery in the strait begins in March.

 

[MGH]

Hey Yammi5 do have the email address. We do have some that are on salt. No freezer there. If they still want them we can find out where to take them.
Thanks

 

[tubber]

My theory: that area gets nasty brown algae blooms. Dead algae depletes oxygen, so colder weather perhaps mixed with a sudden wind storm caused a quick turnover as seen in lakes and the herring were trapped in hypoxic water. It happens to kokanee on Okanagan lake some years.

 

[yammy5]

Hey MGH - can you email Jan Lovy at the Pacific Biological Station to see about sending some herring in for analysis. As I said, there is a great interest in this. Good work!

Jan Lovy, Ph.D.
Herring Conservation and Research Society
Pacific Biological Station
Aquatic Animal Health Unit
3190 Hammond Bay Rd
Nanaimo, BC V9T 6N7
Email: Jan.Lovy@dfo-mpo.gc.ca
Phone: (250) 713-5654

 

[MGH]

Done! thanks yammy5