Hawaii-based Dolphin Quest has terminated its animal loan agreement with Dolphinaris Arizona and is evaluating next steps for its remaining two dolphins at the facility.

Kai, a 22-year-old dolphin who died at Dolphinaris near Scottsdale on Thursday, was on loan from Dolphin Quest to participate in education and experiential learning programs for the public.

"The Dolphin Quest team is heartbroken over the loss of our beloved Kai," the statement read.

Dolphin Quest said they are looking at all options, including the removal of its two remaining dolphins, Liko and Noelani, from the facility. The facility opened in 2016 with eight dolphins, half of which have died in that time.

"The safety and health of our animals is our top priority," said Dr. Rae Stone, co-founder of Dolphin Quest. "In spite of their best efforts, the animal health concerns have not been resolved at Dolphinaris."

Dolphin Quest said they have a senior marine mammal specialist on site at Dolphinaris who is closely monitoring the dolphins. Liko and Noelani are alert and in good condition at this time, according to the statement.

Dolphin Quest said they have contacted the USDA and are working with them on next steps.

Dolphin deaths in the desert

Kai died Thursday morning after his condition began deteriorating, and he had difficulty swimming, eating and breathing, according to a statement from Dolphinaris.

The dolphin showed signs of declining health two weeks ago and was treated, according to Christian Schaeffer, general manager for Dolphinaris.

"We made the extremely difficult decision to humanely euthanize Kai ensuring he would pass peacefully," Schaeffer's statement read.

Schaeffer did not immediately respond to more requests for comment from The Republic.

Kai's death marks the fourth dolphin death since the facility opened in 2016 and comes just a month after Khloe, an 11-year-old Atlantic bottlenose dolphin, died on Dec. 30 after a chronic illness.

Other deaths included:

Bodie , a 7-year-old bottlenose dolphin, died of a fungal infection Sept. 23, 2017. Dolphinaris originally reported the cause of his death as a rare muscle disease, but the National Oceanic and Atmospheric Administration released a report to local activist Laurice Dee, who has opposed the facility, that said Bodie died of a fungal infection. That prompted activists to speculate if desert conditions are appropriate for dolphins. Dolphinaris Arizona spokeswoman Jen Smith told The Arizona Republic in June 2018 that the “muscle disease was secondary to a fungal infection.”

, a 7-year-old bottlenose dolphin, died of a fungal infection Sept. 23, 2017. Dolphinaris originally reported the cause of his death as a rare muscle disease, but the National Oceanic and Atmospheric Administration released a report to local activist Laurice Dee, who has opposed the facility, that said Bodie died of a fungal infection. That prompted activists to speculate if desert conditions are appropriate for dolphins. Dolphinaris Arizona spokeswoman Jen Smith told The Arizona Republic in June 2018 that the “muscle disease was secondary to a fungal infection.” Alia, a 10-year-old bottlenose dolphin, died May 22, 2018, of an acute bacterial infection that officials said “spread quickly throughout her body.”

Smith told The Republic on Friday that they were devastated by the losses and had hired an external pathologist to conduct a necropsy — an animal autopsy — to determine what caused Kai's death.

Feds assessing the situation

Federal officials confirmed Friday they are assessing the situation at Dolphinaris, located on the Salt River Reservation just east of Scottsdale,

The Animal and Plant Health Inspection Service, an arm of the U.S. Department of Agriculture, said in a statement Friday that officials are aware of Kai's death and "working on the next course of action." The statement did not specify what that might include.

The agency monitors animal care throughout the United States.

Protesters show up in full force

In a statement issued Friday, the Washington, D.C.-based Animal Welfare Institute urged the Health Inspection Service to conduct a full investigation.

“We strongly urge that the remaining four dolphins at this facility be confiscated and returned to their facilities of origin,” wrote Dr. Naomi Rose, a marine mammal biologist for the institute, in a letter Friday to the Health Inspection Service.

Rose also requested that an external team -- including an expert Health Inspection Service veterinarian and an expert nongovernmental organization veterinarian, as well as other external specialists with whom Dolphinaris is working -- conduct an investigation into the conditions at Dolphinaris.

Supporters of People for the Ethical Treatment of Animals, or PETA, joined a protest about Kai's death Saturday at Via de Ventura and Pima Road.

"Dolphinaris Arizona's deadly dolphin prison is out of touch with public sentiment — and there's no excuse for keeping it open," said Tracy Reiman, executive vice president of PETA.

The facility has faced opposition since its opening was announced, with many critics saying that dolphins do not belong in the desert.

Rose raised concerns about the risks to dolphins posed by valley fever and other aerosolized pathogens that are present in the desert.

Dee, who has called for the closure of Dolphinaris, has been monitoring the dolphins with concern.

"Four is enough!" Dee wrote in a Facebook post. "We must end dolphin captivity here in Arizona for the sake of the remaining four Bottlenoses."

Reach the reporter at lorraine.longhi@gannett.com. Follow her on Twitter: @lolonghi.