Greenback Flounder – Rhombosolea tapirina

Greenback Flounder Rhombosolea tapirina: Flounder, 1872, by Frank Edward Clarke. Purchased 1921. Te Papa (1992-0035-2278/24)
Greenback Flounder Rhombosolea tapirina: Flounder, 1872, by Frank Edward Clarke. Purchased 1921. Te Papa (1992-0035-2278/24)

Greenback Flounder – Rhombosolea tapirina

Description

The back of this species is, as its name would suggest, dark green. Some greenback flounder specimens have many small black spots on their backs as well, whilst others only a few.  The entire underside is white.

It has a pointed snout. The front of the body is more triangular in shape than any of the other New Zealand founders. The first ray of the ventral fin is situated directly below the eye.

The greenback flounder has a distinctive fleshy extension of the upper jaw that partly overlaps the lower jaw. The lower eye is slightly forward of the upper eye. According to Arthur W. Parrott in The Queer and the Rare Fishes of New Zealand,  the dorsal fin has 67 rays.

Size of Greenback Flounder

The maximum length attained by this species of flounder is about 50 cm (20 inches). The females are larger. The longest male greenback measured by Graham was 35 cm (14 inches).

How to Cook Greenback Flounder

The greenback is one of the best eating of all the flounders. The flesh is white, moist and has excellent flavour. Flounder is one of the easiest fish to prepare and cook.

Rather than filleting as one would with round fish it is simply gutted and gilled only and cooked whole. Remove the head if you prefer. Scaling is unnecessary.

Flounder is best coated in flour and cooked in a pan with butter. Sprinkled with a little salt and pepper, along with perhaps a squeeze of lemon juice. Serve whole on a dinner plate. Scrape and eat the flesh with a fork from one side, skin and all. Leave the bones in place. Then turn it over and eat the flesh from the opposite side.  

Where Found

Greenbacks are found almost exclusively along the east coast of the South Island in waters to a depth of approximately 100 metres. It is one of the least abundant of the flounders found in New Zealand. Also found in southern Australia. It is more common in shallow waters in the autumn so they do tend to migrate at certain times of the year. According to David H. Graham, they spawn about June and July.

Graham also saw occasional specimens from Ohiwa Harbour, Manukau Harbour and from Parenga, North of Auckland. Occasionally small quantities of greenback flounder are recorded in Te Waihora – Lake Ellesmere.

The only species Graham found to be feeding on greenback flounder was red cod and then only on small ones.

Flounder Catch Limits

It is important that you check permitted fish length and bag limits before you go fishing. Here is a link to the recreational fishing rules for the South-East area, including closures, restrictions, and other important notices. This is for the Canterbury, Otago and Southland east coast. If you have any questions contact by email info@mpi.govt.nz 

What Do Greenback Flounders Eat?

Their food consists of small fish like ahuru (looks similar to a small red cod) and yellow-eyed mullet up to about 100mm in length, shellfish, four species of crabs, and shrimp, along with numerous different worms. They also feed on copepods, amphipods, isopods which are small crustaceans, along with bottom forms of whalefeed.

How to Catch Greenbacks

Greenback will take a small soft bait skipped across the bottom, as well as a soft bait or bucktail jig fished from a boat. Perhaps surprisingly they will take quite bright colours like yellow and pink lures. Greenbacks can also be taken in beach seine nets and by spearing with a torch at night but as pointed out above they are much less common than other flounder species.    

Graham also found that this flounder did not inhabit the very shallow waters of Otago Harbour as did the sand flounder. This observation was borne out by sport anglers who used to go spearing flounders on the mudflats in Otago harbour.  

References

A Treasury of New Zealand Fishes By David H. Graham

The Queer and the Rare Fishes of New Zealand by Arthur W. Parrott.

Collins Guide To The Sea Fishes of New Zealand by Tony Ayling, illustrated by Geffrey J. Cox.

 

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