GULFPORT (AP) — The deaths of five young dolphins over the past week has marine scientists concerned.

The dolphin calves washed-up along the beach in Harrison County, but it’s not yet known what caused their deaths. Tests are being conducted.

Dr. Moby Solangi says in the recovery of stranded dolphins, whether dead or alive, time is critical. With the ‘‘calving’’ season now under way, he says there may be more young dolphins getting stranded along Mississippi beaches.

Solangi says when possible, injured or sick animals are nursed back to health. In the case of death, studies in the lab are done to try and pinpoint the cause.

Scientists say the tests identify disease or identify any heavy metals, poisonous chemicals or pollutants which may have contributed to the animal’s death.