Season 4

Jonah and Nicole take George's niece Melissa to the country where they come across an injured coyote pup. When Melissa becomes attached to the pup, the Roberts must convince her to return him to the wild where he belongs.

While exploring Bailey's Cove, Jonah & Nicole come across a deep sea gill net that could ensnare the area's sealife. Soon after they meet Agnes Calhoun, an old friend of Grant's with a history of aggressive ecological crusading, who inspires Jonah to try to tackle the net himself with near-deadly consequences.

The Aquarium holds an Adopt-a-pet program to help raise funds. Grant's life is turned upside down by this.

Lying and cheating is not what a healthy relationship is about, unfortunately Jonah learns that the hard way. After getting a new girlfriend, he wants to impress her in every way, because she's wealthy and he doesn't want to lose her.

While a member of the school gymnastics team, Nicole befriends a girl whose mother was once a prima ballerina now confined to a wheelchair and must help convince her she can still lead a normal life following her accident.

Grant and his new protegé intern work to devise a kit to detect the presence of the toxin known as ""Red Tide."" When their attempts fail, Grant is saddened to discover his assistant's ambition for fame overshadowing his professional ethics.

The presence of an avian virus affecting the chicken farm of one of George's old friends leads the gang to an illegal smuggling ring dealing in rare birds. One of the persons involved in the ring is revealed to be J.L.'s new pilot, Rick, who takes Nicole on one of his runs.

While Jonah works up the courage to ask Nicole's friend Emma to a dance, Zuzette, a biologist on exchange from France, races to collect five tropical frogs that accidentally escaped from their aquarium.

On the ninth anniversary of his wife's death, Grant takes Nicole deep sea sailing. When they're suddenly caught in a squall and forced to abandon ship, J.L. and Jonah fear the worst.

Jonah's pastime of the week has switched to tennis, and he takes on an attractive young lady named Chris as his personal coach. He fails to understand however that love is just part of the scoring in a tennis game.

While enrolled in a scuba diving certification program, Jonah and his friend Derrick accidentally injure a wolf eel with an underwater spear gun. When Jonah takes the blame, Derrick must decide whether or not to come forward and face the music.

A visit from an old friend drops a much sought-after dolphin statue in Nicole's possession. When an art collector will stop at no means to get a hold of the artifact, the Aquarium staff race to uncover the secret behind it.

Jonah's pastime of the week has switched to photography, and when J.L. is accused of pilot error when her helicopter crashes and a valuable cargo is lost, he sets out to prove that the mishap was due to sabotage.

The Roberts discover one of their favourite forests has been bought by a survivalists school. When Jonah decides to enroll, he is put to the test in a competition against the school instructor's daughter.

Nicole and Jonah befriend a young Czechoslovakian student visiting Vancouver who chooses to defect to Canada. As his teacher tries to convince Grant to deny him asylum, his fellow students decide to join him in staying.

Nicole is injured during a mountain climbing practice and develops a fear of heights. When she decides to continue with her climb, she is forced to confront her fear when a dire situation arises.

Grant and Jonah recover an injured seal and discover a mysterious implant in it's brain. When an intelligence agent decides the seal must be killed, the Aquarium staff race to save the creature's life before it's too late.

The Roberts assist in an archaeological dig in a nearby forest: Grant must deal with an arrogant paleontologist convinced her theories are correct, while Nicole must handle a fellow student who keeps stealing her credit for unearthing fossils.

The Aquarium staff investigate a series of wounded bald eagles that leads them to a nearby flying school and a pilot with a vendetta against the creatures. Grant must convince local farmers to stop aiding the man in wiping out the eagles from the area.

When a killer whale carcass exhibits some unusual wounds, the Aquarium determines it to be from a wayward narwhal trapped in a nearby channel. When a wealthy philanthropist offers to finance the expedition, Dr. Roberts and his children jump at the chance to track the rare creature down, but are his intentions truly humanitarian?

While Nicole was out in the woods taking nature photos, she meets Pete Bartlett (Gordon Pinsent) who was really a poacher.

Upon returning from a camping trip to visit his old friend Pete, Grant discovers he is the recipient of the Fairfax Award worth sixty thousand dollars. When it is revealed the award is a distraction to the environment damage caused by the company sponsoring the award, Grant must decide whether to accept it or refuse.