LA JOLLA, Calif. -- An animal protection group Monday reported the first harbor seal pup birth of the season at the Children's Pool, just days before a legal battle is due to heat up over how much protection the marine mammals will receive.

Dorota Valli, the seal campaign coordinator for the Animal Protection and Rescue League, said a volunteer spotted the black pup around 9 p.m. Sunday.

The league keeps volunteers at the Children's Pool to keep people from harassing the seals, Valli said.

The nursing seals used to be protected by a rope that kept people away, but the city of San Diego was barred by a Superior Court judge from putting up such a barrier this year.

The judge, in affirming a 2005 ruling, also ordered the city to remove sand buildup and clean seal feces that make the water unhealthy for humans.

The birthing season normally runs from January to May.

The APRL plans to argue in a federal court hearing on Feb. 21 that the federal Marine Mammal Protection Act trumps state law, so the rope should be put up.

A 1931 trust agreement between the city and Ellen Browning Scripps called for the area to be kept as a place where children can swim.