3 sentences

1. 鲑鱼在淡水中产卵。

   guī​yú zài dàn​shuǐ zhōng chǎn​luǎn.

   Salmon lay their eggs in fresh water.

   Source: Tatoeba

2. 每年秋天，成群的鲑鱼都会游回上游产卵。

   měi nián qiū​tiān, chéng​qún de guī​yú dōu huì yóu​huí shàng​yóu chǎn​luǎn.

   Every autumn, schools of salmon swim back upstream to spawn.

   Source: Dong Chinese Dictionary

3. 鲑鱼每年都会逆流而上回到它们出生的地方产卵。

   guī​yú měi nián dōu huì nì​liú'ér​shàng huí​dào tā​men chū​shēng de dì​fang chǎn​luǎn.

   Salmon swim upstream every year to return to their birthplace to spawn.

   Source: Dong Chinese Dictionary