NIWA survey finds rare fish and new seafloor habitats

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NIWA scientists sur-veying shallow water coastal habitats off the east coast of Northland have found a rich diversity of macroalgal meadows, shellfish beds, sponges, and rare fish species, including a frog-fish and possibly a new species of seahorse.

The survey was conducted using a small beam trawl research net with GoPro cameras attached, as well as dropped stationary cameras both with and with-out bait to attract fish.

Its goal was to discover what types of habitats were present and where they occurred; and what juvenile and small fish

were associated with them. The information gathered will ultimately help inform fishery and ecosystem management decisions.

NIWA marine ecologist Dr Meredith Lowe says the resulting information helps to fill in gaps in scientific knowledge about habitats created by plants and animals and their small fish inhabitants, such as juvenile snapper.

The survey results are helping to build a national fish-habitat classification and inventory of New Zealand’s coastal and shelf zone.

“Our knowledge of what lives in the coastal zone is scant. For instance, while we believe estuaries provide critical nurseries for a range of fish species, we cannot prove that until we know their relative contributions compared to possible alternative coastal nursery areas.

“We also know this coastal region is one of the most species diverse nationally, and this work has shown that this rich diversity also extends to seafloor habitat types, and the fish species which live in them. As an additional bonus, a number of new species of red algae were also discovered."

Video from GoPro cameras (a new science technology development for the team) revealed some surprises, with a juvenile white shark bumping into the camera bait pot as it swam past, and a group of dolphins talking to each other as they checked out the sampling net down on the seafloor under tow.

The seahorse is undergoing scientific identification to assess whether it is a new species.

Dr Lowe says it will be some time before scientists can confirm its identity and how rare it is worldwide. It is about 3cm long and predominantly brown in colour.

Meanwhile, the Ministry for Primary Industries has just released a report that reviews existing knowledge about fisheries species and their linkages to biogenic habitats.