Like other slimeheads, orange roughy is slow-growing and late to mature, resulting in a very low resilience, making them extremely susceptible to overfishing.

The 19 to 25 ventral scutes (modified scales) form a hard, bony median ridge between the pelvic fins and anus.

[citation needed] Orange roughy are generally sluggish and demersal; they form aggregations with a natural population density of up to 2.5 fish per m2, now reduced to about 1.0 per m2.

These aggregations form in and around geologic structures, such as undersea canyons and seamounts, where water movement and mixing is high, ensuring dense prey concentrations.

[2] Orange roughy are oceanodromous (wholly marine), pelagic spawners: that is, they migrate several hundred kilometers between localized spawning and feeding areas each year and form large spawning aggregations (possibly segregated according to gender) wherein the fish release large, spherical eggs 2.0–2.5 millimetres (0.079–0.098 in) in diameter, made buoyant by an orange-red oil globule) and sperm en masse directly into the water.

The fertilized eggs, (and later larvae) are planktonic, rising to around 200 m (660 ft) to develop, with the young fish eventually descending to deeper waters as they mature.

The time between fertilization and hatching is thought to be 10 to 20 days; fecundity is low, with each female producing only 22,000 eggs per kg of body weight, less than 10% of the average for other species of fish.

[4] The maturation age used in stock assessments ranges from 23 to 40 years,[5][6] which limits population growth/recovery, because each new generation takes so long to start spawning.

[2] The orange roughy is the longest-lived commercial fish species, and does not breed every year, which has important implications for its conservation status.

[10] This species was first given the common name "Orange Roughy" by scientists in New Zealand in 1975 following the discovery of large aggregations during a deep-water research cruise.

[11][12][13] A large scale fishery for orange roughy subsequently developed around New Zealand, and imports into the United States increased where it was renamed from the less gastronomically appealing "slimehead" through a U.S. National Marine Fisheries Service program during the late 1970s that identified underused species that should be renamed to make them more marketable.

In addition, a number of ecolabels exist to help retailers and consumers identify seafood that has been independently assessed against a robust, scientific standard.

[citation needed] In 2010, Greenpeace International added orange roughy (deep sea perch) to its seafood red list, which contains fish generally sourced from unsustainable fisheries.

[15] A 2003 joint report by the TRAFFIC Oceania and World Wildlife Foundation Endangered Seas Program argues, "probably no such thing [exists] as an economically viable deep-water fishery that is also sustainable.

[19] Based on average consumption and the recommendations of a National Marine Fisheries Service study, in 1976 the FDA set the maximum safe mercury level for fish at 1 ppm.

[2] Because of its longevity, late maturation and relatively low fecundity, orange roughy stocks tend to recover more slowly than most other species.

[citation needed] The Ministry for Primary Industries is responsible for the implementation of the QMS and its enabling legislation, the Fisheries Act 1996.

For many fisheries, management settings allow for a "fishing down" period during which the biomass is reduced to a level that will provide the maximum sustainable yield.

The rate of this "fish-down" can vary depending on the objectives of the fishery, but catches would then be more strictly controlled to maintain the biomass at around 40,000 tonnes.

This was later found not to be the case and a number of fisheries were closed completely or had catch limits reduced to one tonne to allow the stocks to rebuild.

This was because of a strict interpretation of the Fisheries Act that required an accurate estimation of the biomass that could support the maximum sustainable yield.

As a result of this decision, the Fisheries Act 1996 was amended to allow TACs to be set based on the best available information in the absence of an estimate of the biomass that could support the maximum sustainable yield.

Based on this output, the fishing industry agreed to aim to maintain the orange roughy stocks within a management target range of 30–50% of the unfished biomass.

[citation needed] The Australian orange roughy fishery was not discovered until the 1970s, but by 2008, the biomass of some stocks remained high while others was estimated to be down to 10% of the unfished level after years of commercial fishing.

[34] In July 2020, a leading US-based MSC consultancy (conformity assessment body or CAB) acting for a group of Australian eastern zone orange roughy quota holders, released a scoring report recommended that the orange roughy eastern zone stock be given Marine Stewardship Council accreditation, scoring the fishery and its management highly (289/300) in each of the three assessment principles.

However, environmental groups the Australian Marine Conservation Society and World Wildlife Fund raised late objections.

[citation needed] The Arbitrator issued her decision in three iterations in early 2021 each following representations from the Appellants, CAB and Fishery Client.