Records dating back almost 100 years could hold dialectical differences or lost words in Cook Islands Māori – and they have been sitting in a box at the Auckland Museum for all those years.

Auckland Museum’s head of natural sciences, Tom Trnski, spends plenty of quiet hours working through thousands of jars of preserved fish stored at the museum.

The specimens are all labelled but some have been separated from their full paperwork. It means it is not always clear what each fish is, where it came from, when it was collected and when it arrived in Auckland.

But one day, Trnski stumbled on an old filing box with handwriting that looked familiar to some he had seen on some of those undocumented fish jars.

Inside the box was a record book titled Foreign Fishes: Rarotonga. It held carefully written out entries, the earliest of which dates back to 1926 (multiple fish of multiple species are referred to as fishes).

Trnski was sure these records belonged to those orphan fishes he had found. He already knew they were tropical but now he knew for sure they were from Rarotonga in the Cook Islands.

The record book contains details of 120 fishes from the Cook Islands collected between 1926 and 1934 by Captain Vellenoweth, who at some stage was the resident government agent at Aitutaki.

It includes where the fish were collected from, their Latin names and their local names.

So the museum organised a hui with members of the Cook Island community both here and in the Cook Islands, to see whether those names were right.

“They recognised a lot of the names and matched them to the species but with some they recognised the fish but not the name,” he said.

“Either they have lost the name for the fish in the last 90 years or the name is from a different island group. It is actually really neat that we could use that to recover names that used to exist.”

Trnski said some Cook Island Māori names were also similar to New Zealand Māori names of fish, although not of the same species.

One local fish in particular, kokopu, has the same name as a Cook Island fish – they look very similar, which may be why they have the same name.

“It is quite neat to see that link between the languages, that when Polynesians arrived here they started naming species here that reminded them of where they had been before.”

He said having these records nearly a century on from when the fishes were collected meant researchers could look into what had changed for the various species in the collection.

Warming seas, climate change and repeated La Niña events all affect the ocean’s precarious ecosystem, and it is possible that fishes in the collection won’t be as abundant as they used to be.

The Bishop Museum in Hawaii has a database of local names for marine species from the Pacific, which the Auckland Museum can contribute to and grow the knowledge base.

• Reported by Sapeer Mayron/Stuff