Earth Changes
The country's office for environmental protection has said the animals do not have injuries from getting caught up in fishing nets or lines.
There are also no marks on their bodies from possible collisions with boats.
Both scenarios are common causes of sea lion deaths or injuries.

Locals have reported seeing birds around their house — and sometimes inside their house — like this juvenile Wilson's Warbler, still learning how to fly.
Area residents have been noticing the little yellow and green birds in their yards — sometimes acting punch-drunk — following the cold snap and snowfall last week.
While it seems logical that the behavior is due to the cold snap, there may be two separate things going on simultaneously.
A large number of dead birds in the Fryingpan Valley was reported by residents Wednesday on the Roaring Fork Road and Weather Facebook page.
The event might not be exclusive to the Roaring Fork Valley — on Saturday, the Las Cruces Sun News reported that migratory birds are dying in "unprecedented" numbers throughout New Mexico.

Coronet Peak is in the midst of a three-day spring snow storm with 15cm of fresh snow on Tuesday morning.
Treble Cone had up to 40 centimetres of fresh snow dumped at the saddle on Monday night while Coronet Peak and Cardrona skifields had 15cm.
Metservice meteorologist Lewis Ferris said more snow was forecast.
Wednesday would bring showers and snow down to 1200 metres, and cold air would drop the snow level to 700m on Thursday, he said.
Parts of Rangpur, Kurigram, Gaibandha, Jamalpur, Pabna, Natore, Sirajganj, Manikganj, Rajbari, Munshiganj, Faridpur, Madaripur, Shariatpur and Dhaka districts still have flood water, according to the Department of Agricultural Extension (DAE). DAE data showed a total of 260,000 hectares of land have been damaged totally by the more than two-month long flood from June 26 to August 31.
Multiple videos of the insect invasion started making the rounds online on Monday, promptly becoming a viral topic in Russia. The bug buildup began in the city over the weekend, becoming particularly intense on Monday morning.
The EMSC said the quake hit at a depth of 320km - nearly 200 miles - at around 03:41 UTC, or 04:41 UK time.
There are no reports of damage or injuries at the time of writing.
However, there have been at least 14 reports of people feeling the quake, according to EMSC.
Accounts vary widely, with some reporting stronger feelings of shaking than others, with the duration of the quake also reported differently amongst people.

The latest Leighton Buzzard quake is thought to have been an aftershock from the magnitude 3.5 quake that was felt on September 8
The tremor in Bedfordshire, which hit at 11.20pm on Sunday night, was measured by the BGS at magnitude 2.1.
It is thought to have been an aftershock from the magnitude 3.5 quake that was felt on September 8.
A BGS spokesman said: 'The most recent event was over 100 times smaller than the event on September 8 in the same area.
'The occurrence of smaller events from other previous UK earthquakes is not unknown.
'The small event that occurred in Bedfordshire last night could have occurred because all the stress in the rocks was not relieved by the event on September 8 in the same area or it caused a slight change to the stress regime in that location.
'There is constant ongoing research in the academic world on the issue of aftershock occurrence.'
The blaze was in central Portugal around Proença-a-Nova, 200 kilometres (124 miles) north of Lisbon.
The fire's perimeter stretched more than 55 kilometres (34 miles), local Civil Protection Agency commander Luis Belo Costa told a news conference, adding that an "extraordinary" amount of tinder-dry vegetation was fueling the flames.
What happened? A crack opened in Earth's magnetic field. Solar wind poured in to fuel the display. Such cracks form often during weeks around equinoxes--a pheomenon known as the "Russell-McPherron effect." With the autumnal equinox only 1 week away, more green clouds could be in the offing. Stay tuned.











Comment: Related: Growing number of dead birds in southern New Mexico raise alarm for wildlife experts