The island was completely deserted.
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#3222725: 島にはまったく人気がなかった。(人気 = ひとけ)
人影（ひとかげ）and 人気 are interchangeable in this context. 人気（ひとけ）consists of 人の気配（ひとのけはい）. 気 means “atmosphere/mood/feeling/condition”. So, 人気がない（ひとけがない）literally means “I cannot feel the atmosphere of living people here”.
Please note that 人気 can be pronounced as either ひとけ or にんき. 人気（にんき）means “popularity”, and 人気がない（にんきがない）is “someone/something is unpopular”.
From the overall context with 島には, you cannot interpret 人気 as にんき, but ひとけ. However, if you change the original sentence to 島はまったく人気がなかった, it is more likely to be interpreted as “This island was not popular (among tourists) at all” rather than “The island was completely deserted.” – It’s a very tricky lesson for には as a particle.