>> Janell Roller coaster the last 3 months at the Shedd Aquarium and it took another sad turn today this evening.

The shed is reporting the death of a 4th beluga.

Well, 26 year-old name all Cyrus, who was part of the first pond for females brought to Chicago back in July.

The shut took in a total of 10 blue bus from a close Marine Park in Canada.

Our Patty, what Lee spoke with the sheds lead veterinarian just last week to get an update on the health of the whales who remain under careful observation.

>> There's always going to be risk, especially in a rescue.

And we do everything we can to mitigate that risk.

But it is still there.

They lived in one place with one way of interacting with humans and with each other for in some cases, multiple decades, then they're moved to a new facility with different humans, different animals and a little bit of a different way of life.

So we're trying as much as we can to make.

The transition as slow as possible.

But of course, the actual move from Canada to the AZ facilities.

Is a large.

>> Some animal rights activists opposed the whales captivity and their transfer.

That criticism grew louder after 2 sheds, newcomers died along with one of the claims resident the Lucas.

>> It's devastating deeply, deeply personal.

this is giant group of people dedicated their entire lives to the love of these animals.

>> But Dr Tang says circumstances at Marine land including crumbling infrastructure and water, quality issues made the rescue urgent and absolutely necessary.

>> It is not a marker of the people who spend every day with those animal, the humans, the care takers caring for these animals cared for them very, very much.

But there were concerns they were at the end of their line in terms of resources.

So there was no other option for these whales.

It was either find a new home for these an ice.

>> Dr Tang says it's too soon to know what caused the deaths of peek at you and rain who arrived in July as well as Beethoven.

A longtime resident.

>> A economy crops.

The exam is is very complex and involves a lot of different people.

And it's sort of like a jigsaw puzzles.

So we want to wait until we have as much information as possible before we share anything.

>> That hasn't stopped speculation from swirling that blue cause may have been sick and carrying diseases when they arrived.

That shed Dr Tang shot down those rumors.

So any time an animal moved, including in this rescue situation, we run a panel of tests that cover infectious diseases are things that we're worried about bringing in too.

>> Another facility and they were negative for all of those really big infectious diseases.

>> Dr Tang says the focus continues to be on the well-being of the cause.

She says the whales are being monitored around the clock with staff paying particular attention to things like a change appetite.

>> When we say day by day, hour by hour, we truly mean that they're all on a different path.

I think we have months before we take a to be totally honest.

This is going to be a long process of acclamation.

Yes, we still have 24, 7 monitoring.

Guess our phones are constantly on at all hours of day and night.

And so it really looks like we're asking, what is today look like?

What tomorrow look like?

It's really about survival and triage and wanting these whales to thrive.

>> While there have been low points in the journey, Dr Tang says there have been moments of joy as well.

>> I think the moment of reuniting those 2 groups of females that lives together.

Marineland was really, really beautiful and watching how they greeted each other and Brogdon each other like oh, my gosh.

same thing happen to you.

The privilege of spending time with them.

The privilege of getting to know them every day is a highlight.

>> For Chicago tonight, I'm patty.

>> And the wells deaths all