וַיִּבְרָ֣א אֱלֹהִ֔ים אֶת־הַתַּנִּינִ֖ם הַגְּדֹלִ֑ים וְאֵ֣ת כָּל־נֶ֣פֶשׁ הַֽחַיָּ֣ה ׀ הָֽרֹמֶ֡שֶׂת אֲשֶׁר֩ שָׁרְצ֨וּ הַמַּ֜יִם לְמִֽינֵהֶ֗ם וְאֵ֨ת כָּל־ע֤וֹף כָּנָף֙ לְמִינֵ֔הוּ וַיַּ֥רְא אֱלֹהִ֖ים כִּי־טֽוֹב׃
At nilikha ng Diyos ang malalaking halimaw sa dagat, at ang lahat ng nilalang na may buhay na gumagapang, na pinag-umpukan ng tubig ayon sa kanilang mga uri, at ang lahat ng ibong may pakpak ayon sa kanyang uri. At nakita ng Diyos, na ito ay mabuti.
Rashi
התנינים THE HUGE CREATURES — the large fishes that are in the sea; and according to the statement of the Agada (Bava Batra 74b) it means here the Leviathan and its consort which He created male and female. He, however, killed the female and preserved it in salt for the benefit of the righteous in the time to come, for had they been permitted to be fruitful and to multiply the world could not have endured because of them.
Rashbam
התנינים הגדולים, even though, in the previous verse, the Torah reports on the directive for the waters to produce multiple reproductions of each species which has its habitat in the waters, and we could have thought that this did not include gigantic creatures such as whales, the fact is they (it) too had been produced by the waters at the same time. The species described as Leviathan, Nachash beriach and Leviathan beriach in Isaiah 27,1 and the Leviathan described in Job 40,25 are what our verse here refers to.
Sforno
ויברא אלוקים את התנינים, the evolutionary powers of the waters did not suffice for this task. They could not produce the original sea-monsters without having been provided for this with seed by the Creator.