Seafood to Avoid
Skates
Scientific name: Rough skate Raja nasuta, Smooth skate R. innominata
Other names: manumanu, pakaurua, uku, waewae, whai (Maori), barndoor skate
(NZ), suei, gangiei (Japan), gaori (Korea)
Ranking: E (Red - Worst Choice)
|  |
Description: These distinctive large ray-like fish that occur all around New Zealand are caught in trawl nets and on lines in multiple management areas. The largest of these, QMA 3, accounts for more landings than all others combined.
The main concerns with this fishery are: the absence of basic biological information on each skate species, the unknown sustainability of recent catch levels in QMA 3 or the total quota, the limited research on skates, the lack of a quantitative stock assessment and the lack of a management plan. Also, impacts on deepwater habitats and bycatch of marine mammals, seabirds and non-target fish in other fisheries where skates are bycaught.
The latest stock assessment states: "No estimates of current or reference biomass are available Relative biomass estimates from trawl surveys in QMA 3 and QMA 7 revealed declines for both species in recent years. It is not known if recent catch levels or the total quota are sustainable or at levels that will allow the stock to move towards a size that will support the maximum sustainable yield." (MFish 2007, p833)
Market: Exports of around $0.6 m to Asia.
Status and sustainable yield
Status: Unknown.
Annual catch limit: A total quota of 867 tonnes for smooth skates and 1989 tonnes for rough skate in 2003-04.
Recorded catch: Reported landings of 1,699 tonnes of rough skate and 715 tonnes of smooth skate in 2005-06.
Population size: Unknown.
Stock trends: Biomass indices declined significantly since 1991.
Fishing method
Method: Trawling and on lines.
Habitat damage: Trawling damages deepwater habitats.
Bycatch: Skates are caught as bycatch in a range of fisheries including hoki. Seabirds and marine mammals are caught in this fishery.
Ecological effects: Mainly the impact of trawling and the loss of large adults in the fishery.
Management
Stock assessment: No quantitative stock assessments.
Management plan: No.
Quota Management Species: Yes, since 2003.
Biology
Distribution: Both of these endemic species occur all around New Zealand. Rough skate is more common in coastal waters while smooth skate is usually found in deeper waters to 200m.
|
Rough |
Smooth |
| Maximum age
(years): |
9 |
24+ |
| Age at sexual maturity: |
4-6 |
8-13 |
| Growth rate: |
Unknown |
Unknown |
| Reproductive output: |
High |
Medium |
| Size/age
exploited: |
Unknown |
Unknown |
References:Report from the Fishery Assessment Plenary, May 1997: stock assessments and yield estimates. Part 3: Pilchard to Yellow-eyed Mullet. Science Group, Ministry of Fisheries; Guidebook to New Zealand Commercial Fish Species, Revised Edition 1990, NZ Fishing Industry Board.
This
page was updated on 9 November, 2007 |
