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Should we eat the Orange Roughy?

Should we eat the Orange Roughy? Justifying MAR-ECO – the Orange Roughy experience. A medium sized fish with a firm, tasty white flesh, the Orange Roughy is a gourmet item on many restaurant menus.

When large aggregations of the fish were first found by adventurous deep-sea fishermen, it started a gold-rush phenomenon in the search for new fishery resources.

BUT the deep-sea environment is different. Practices that have been used in coastal fisheries cannot be used to exploit deep-sea fisheries in any kind of sustainable way, as the Orange Roughy gold miners learned to their dismay.

The Orange Roughy fishery has been boom and bust. The “hotspots” initially discovered yielded such high volumes of fish that they overwhelmed handling capacity and much of the first catches were dumped. But within just a couple of years the fish were gone and the hotspot was empty.

The ecology of deep-sea fish is different and scientists believe that each fished out hotspot may never recover.

What irreparable impacts will this cowboy-style deep-sea fishery approach have on these virtually unstudied environments? What global resources are being lost before they have even been discovered?

Called the Orange Roughy because of its bright orange coloration and rough scales, the fishery for the deep-sea fish, Hoplostethus atlanticus, has lessons to teach us that more than justify scientific expeditions to census the deep-sea and study its life-forms, such as the MAR-ECO Project. In particular it underlines the ecological tragedy that can ensue when a fishery is allowed to develop before there is sufficient scientific knowledge and understanding to ensure its sustainable management.

This article and pictures are taken from the WWF / TRAFFIC Oceania report: Managing risk and uncertainty in deep-sea fisheries: lessons from Orange Roughy, published 2003. 

Gold is discovered

The Orange Roughy has a firm flesh that can be easily processed into white, boneless filets that freeze easily. It is a tasty and highly marketable fish. The US is, by far, its largest market. The average length in New Zealand waters is 35cm, although maximum lengths of 60 cm have been recorded in Australian waters.

The Orange Roughy fishery is about 25 years old. It is estimated that over one million tonnes of fish have been landed since the fishery began. The fishery began almost by chance as the over-fishing and depletion of inshore stocks and the declaration of the 200 nautical mile exclusion zone forced commercial fishermen to begin to search for new ocean resources. The advent of new technology, more powerful gear and boats also made it easier to fishermen to leave the waters of the continental shelves and move out to the deep-sea.

There is no consistent definition of “deep-sea”, with limits being given as below 200, 400 and 500m depending on the source. It is also loosely defined as being “beyond the continental break”. Within the deep-sea, however, there are features that affect the current systems and the distribution of deep-sea life forms. Chief among these are seamounts. Many deep-sea fish species are associated with seamounts, either continuously or at specific periods, such as for spawning or feeding. The Orange Roughy is one of these species, being found in large aggregations around seamounts where they gather to spawn or feed.


Seamounts are undersea volcanoes, typically cone-shaped and rising relatively steeply for the seabed. They can be very large features, not only in terms of their elevation, but also in area, as some are more than 100km across at their base (Gubbay, 2003, OASIS Seamount project)
more on seamounts
and more still (on ICES website) 

Boom and bust

Roughy fisheries are characterised by being boom and bust; having incredibly high levels of catches for a couple of years, and then rapidly declining to very low levels without recovering. Although there have been around 30 Roughy fisheries world wide, some still active today, four make good case studies.
The first Roughy fishery was founded by New Zealand fishermen around a seamount area called Chatham Rise. It started in the late ‘70’s, but declined rapidly after 1979.

This was followed by the highly publicised fishery around St. Helen’s Hill in Australian waters. A newspaper headline from 6 May 1989 stated: “Plenty of “gold” on the sea bed”. But only 30 months later, 16 October 1991, the headline read “Action on Roughy too late”.

At its height, the handling and storage practices could not handle to Roughy gold rush, and there was tremendous wastage.

The fishery around seamounts in the northeast Atlantic began in 1991. By 1994 the catch levels had already declined to around 25% of the original level. ICES, the International Council for the Exploration of the Sea, reports that since that time, stocks have not shown any sign of recovery.
The youngest of the four case study fisheries, in the unexplored waters around the Madagascar Ridge in the Indian Ocean, was discovered in 1999 and had already declined rapidly by 2001. Of the around 30 Orange Roughy fisheries that have been established the last 25 years, over half are now reduced to less than 30% of their initial catch levels.

Orange Roughy biology

It is difficult to study the biology of deep-sea fish and their ecosystems. It is both technically difficult and expensive. Many of the traditional methods used to study inshore fish species are of no avail. Despite this, something is now known about Orange Roughy biology.

As many other deep-sea fish, Orange Roughy are long lived. Studies show that they may commonly live more than 100 years (data from both otolith zone counts and radio-isotope ratios). The long life-time implies that they are late to mature (23-40 years of age), that they grow slowly (with an average size at maturity of 24 cm off South Africa and 42 cm in the NE Atlantic). They also have a low fecundity (reproductive rate) and may spawn irregularly. While deep-sea fish species have these life history tendancies, researchers believe that Orange Roughy are the extreme low end of the productivity and high end of the longevity scales.

They are widely distributed throughout the deep-seas, between 500-1500m deep and near topographic deep-sea features. The range includes the Atlantic (from the NE to off north-west Africa), the western Mediterranean Sea, the south Atlantic (off Nambia) and through the ridges of the southern Indian Ocean from Africa to Australia, as well as the SW Pacific Ocean to east of New Zealand and the eastern Pacific, off Chile. They tend to congregate, travelling as much as 200km, around topographic features such as seamounts, plateaus and canyons for spawning and feeding. Orange Roughy populations may also be endemic, localised or resident, associated with specific topographic features and not tending to migrate over large distances.

All of these characteristics make the Orange Roughy highly vulnerable to exploitation. Field experience gained over the fishery’s 25 year history suggests that it is very difficult, if not impossible for local populations to recover from over-fishing.

It is not only the Orange Roughy themselves that are being destroyed. The fishery has very high by-catch levels. Mortality is nearly 100% for these deep water species, many of whom are unknown and poorly studied.

The mechanical effects of the fishery effort are also devastating to the deep-sea environment. Not only are the fragile, slow-to-recover, sea-floor communities of the trawl path destroyed, but the disturbance to the sea-floor sediments may spread the destructive effects over large areas. It is estimated that 40% of today’s trawling effort occurs in the highly vulnerable and unexplored sea-floor zones deeper than the continental shelf.Finally, researchers do not know enough about the deep-sea ecosystem to be able to even estimate the effects of removing of a mid-range predator, such as the Orange Roughy. The Roughy is an opportunistic feeder and eats small fish, crustaceans and squid and is defined as feeding at the fourth trophic level.

Lessons learned – future recommendations

It is impossible to develop sustainable fishery strategies without having basic biological understanding of deep-sea ecosystems. Indeed the experiences of the past 25 years are raising the concern that sustainable management may not even be compatible with economically viable profit margins. Without proper assessment we risk losing deep-sea resources and irreparably damaging deep-sea ecosystems, before we even know what is there.

Just as arctic development has different requirements than temperate or even tropical, so deep-sea activities need different management approaches than have been developed for inshore, continental shelf resources. Just as we are coming to understand the climate is a global, inter-related phenomenon, so the deep-sea is a complex interactive environment, and needs to be study as a whole, integrated eco-system. No “one size fits all” solution will work. Sustainable development means taking non-targeted species into account.

New deep-sea fisheries should be developed slowly, with a very precautionary approach stressing long-term, sustainable objectives. There are some species such as Blue Ling, Tusk, Alfonsino, and Redfish that have reproduction and growth rates at the higher end of the deep-sea species scale and for whom sustainable fisheries may be an attainable reality.

The current active encouragement of expanded fishery activities on the parts of some national governments should be stopped. The deep-sea is international, and needs international consensus on its potential exploitation. International trade organisations should prohibit subsidies that encourage over-capacity fishery development.


This article and pictures are taken from the WWF / TRAFFIC Oceania report: Managing risk and uncertainty in deep-sea fisheries: lessons from Orange Roughy, published 2003. Read the report here.


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