The folllowing sentence is an excerpt from the NHK easy article:
https://www3.nhk.or.jp/news/easy/k10012832221000/k10012832221000.html
I've provided the preceding clause for more context.
「ヨコヅナイワシ」は、他の魚に食べられることがなくて、駿河湾の深い海にいる魚などの関係の中で、一番上の魚だということもわかりました。
研究グループは「ヨコヅナイワシ」が深い海の底の近くをゆっくり泳いでいる所もテレビに撮りました。
My understanding of も is that it is the non-logical reverse particle of は in the sense that it also marks the topic of the sentence, and states that whatever comments are made about the も topic are the same about the preceding topic. But the preceding topic in the 2nd clause is 研究のグループ?
I translated the sentence as:
The research group also took video footage of the location where the Yokozuna fish were swimming slowly, near the bottom of the deep sea.
This sentence sounds weird to me and I don't think I really grasp も (it's the particle I struggle with the most). Any suggestions?