Biological State and Trend
History
Exploration for Orange roughy first started in South Africa prior to 1994 but emphasis soon shifted to Namibia when an exploratory fishing license was given to a Namibian fishing company to search for commercial deep-water fish species. The fishery expanded, extending their fishing range into SEAFO CA. By 2008, a three year moratorium on Orange roughy was enforced in Namibia and the fishery has not been re-opened yet.
Table 1 shows vessels that operated between 1995 and 2005 in the SEAFO CA. These vessels were also involved in the Alfonsino fishery during the same period.
Table 1 Orange roughy: Fleet information, Division B1.
| Flag |
ID |
Name |
Length |
GRT |
Built |
HP |
IRCS |
| Nam |
L737 |
Southern Aquarius |
54 |
|
01/01/1974 |
3000 |
V5SH |
| Nam |
L913 |
Emanguluko |
31 |
483.00 |
01/01/1990 |
1850 |
V5SD |
| Nam |
L892 |
Petersen |
43 |
650.00 |
01/01/1979 |
|
V5RG |
| Nam |
L861 |
Will Watch |
69 |
1587.00 |
01/01/1972 |
2116 |
ZMWW |
| Nam |
L918 |
Hurinis |
37 |
784.00 |
01/01/1987 |
1680 |
V5SW |
| Nam |
L1159 |
Bell Ocean II |
57 |
1899.00 |
01/01/1990 |
3342 |
3BLG |
| Nam |
L830 |
Seaflower |
92 |
3179.75 |
01/01/1972 |
4800 |
V5HO |
Seven Namibian vessels (Table 1) were involved for the period that the fishery occurred in the SEAFO CA. The vessels employed the standard New Zealand “Arrow” rough bottom trawl with cut-away lower wings. Sweep and bridle lengths were 100 meters and 50 meters respectively. A “rock hopper” bobbin rig was used. The net had a 5-6 meter headline height when towed at 3- 3.5 knots and had an estimated wingspread of 15 meters. The cod end had a mesh of 110 mm. Each vessel spends on average 12 days at sea.
Habitat and Biology
Climatic zone: Temperate. Bottom type: Unspecified. Depth zone: Slope (200 m - 1000 m). Horizontal distribution: Oceanic. Vertical distribution: Demersal/Benthic.
The aggregating behaviour of Orange roughy contributed to its vulnerability to overexploitation globally. Spawning aggregations of Orange roughy have been targeted in Namibia during winter. Outside the spawning seasons catches were found to be lower due to a more dispersed resource. Orange roughy are also extremely slow-growing and estimates of maximum age are in excess of 100 years.
Recruitment to the fishery is poorly understood as juveniles are not found in significant quantities. Adults have been caught in small amounts in both Angolan and South African waters, but not in large spawning aggregations as in Namibia. Orange roughy distribution also extends beyond the economic zones of the BCLME countries with good catches reported for example on the Valdivia Bank on the South Atlantic Ridge as well as on the fringes of the Agulhas Bank and Walvis Ridge in the southern Benguela.
Orange roughy (
Hoplostethus atlanticus) is distributed globally (Fig. 1), but predominantly in the Southern Hemisphere.
 |
Figure 1 Global distribution of Orange roughy (Branch 2001).  |
Geographical Distribution
Jurisdictional distribution: Straddling between High Seas and EEZ
Fishing mainly occurred on Ewing seamount and Valdivia Bank within the SEAFO CA. These operations started in 1995 and continued until 2005, with the exception of 1998 when no fishing took place. The fishing season usually extends from January to December and catches peak in winter months (May to July), which coincides with the spawning season of Orange roughy.
 |
| Figure 2 Geographical location of fishing activities in the SEAFO CA. |
Resource Structure
Considered a single stock: Yes
In the SE Atlantic Orange roughy may most probably be regarded as a single stock (management unit). In the BCLME region that species occurs within the economic zones of each of the coastal states as well as in the SEAFO CA.
Exploitation
For all the fishing grounds the home port is the same as the landing port, with Walvis Bay and Lüderitz the most important ports. All available landing information is presented in Table 2. However, the bulk of Orange roughy catches were recorded within the Namibian EEZ (Table 3). A total of 1270 trawls were made landing about 290 tonnes of Orange roughy.
Table 2 Catches of Orange roughy made by Namibia, Norway and RSA.
| Nation |
Namibia |
Norway |
South Africa |
| Fishing method |
Bottom trawl |
Bottom trawl |
Bottom trawl |
| Management Area |
B1 |
A1 |
B1 |
| Catch details (t) |
Retained |
Discarded |
Retained |
Discarded |
Retained |
Discarded |
| 1995 |
40 |
|
N/F |
|
|
|
| 1996 |
8 |
|
N/F |
|
|
|
| 1997 |
5 |
|
22 |
|
27#** |
|
| 1998 |
N/F |
N/F |
12 |
|
|
|
| 1999 |
<1 |
|
N/F |
N/F |
|
|
| 2000 |
75 |
|
0 |
|
|
|
| 2001 |
94 |
|
N/F |
N/F |
|
|
| 2002 |
9 |
|
N/F |
N/F |
|
|
| 2003 |
27 |
|
N/F |
N/F |
|
|
| 2004 |
15 |
|
N/F |
N/F |
|
|
| 2005 |
18 |
|
N/F |
N/F |
|
|
| 2006 |
N/F |
N/F |
N/F |
N/F |
|
|
| 2007 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2008 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2009 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2010 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2011 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2012 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2013 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2014 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2015 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2016 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
| 2017 |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F |
N/F = No Fishing. Blank fields = No data available. ** Sum of Catches from 1993 to 1997. # Values taken from the Japp (1999).
Table 3 Orange roughy landings (tonnes) in SEAFO CA and Namibian EEZ.
| Year |
SEAFO CA |
Namibian EEZ |
| 1994 |
N/F |
1 872 |
| 1995 |
40 |
6 288 |
| 1996 |
8 |
17 381 |
| 1997 |
5 |
14 729 |
| 1998 |
N/F |
10 040 |
| 1999 |
<1 |
2 699 |
| 2000 |
75 |
1 344 |
| 2001 |
94 |
874 |
| 2002 |
9 |
1 985 |
| 2003 |
27 |
1 730 |
| 2004 |
15 |
1 106 |
| 2005 |
18 |
297 |
| 2006 |
N/F |
429 |
| 2007 |
N/F |
288 |
| 2008 |
N/F |
6 |
| 2009 |
N/F |
5 |
| 2010 |
N/F |
1 |
| 2011 |
N/F |
1 |
| 2012 |
N/F |
2 |
| 2013 |
N/F |
2 |
| 2014 |
N/F |
1 |
| 2015 |
N/F |
6 |
| 2016 |
N/F |
236 |
| 2017 |
N/F |
440 |
Assessment
The annual CPUE (total annual catch divided by number of trawls) are shown in figure 3. The CPUE was the highest in 1995 and thereafter decreased rapidly to reach the lowest CPUE in 1999. Since then the CPUE seems to have stabilized at a low level until 2005 after which there are no data. It has not been confirmed that this CPUE index reflects stock abundance for a highly aggregating species like Orange roughy.
 |
| Figure 3 CPUE of Orange roughy in tonnes per trawl in Division B1 (SEAFO SC Report 2006). |
Data
Catch records for the period 1995 to 2005 are available (see Table 2 above). The number of hauls made per year are depicted in table 4 and shows that more hauls were recorded in years when the catches were high.
No Orange roughy survey has been conducted in the SEAFO CA.
Table 4 The total number of sets from which Orange roughy catches were derived for the period 1995-2005.
| 1995 |
1996 |
1997 |
1998 |
1999 |
2000 |
2001 |
2002 |
2003 |
2004 |
2005 |
| 20 |
223 |
188 |
0 |
16 |
327 |
295 |
40 |
63 |
46 |
61 |
Overall Assessment Results
Since there is no fishery in recent years or any other independent data available within the SEAFO CA, no assessment can be done at the moment. However, future assessments for Orange roughy should be separated according to fishing ground, similar to what has been done for the New Zealand Orange roughy resource.
Scientific Advice
SC considered available data on Orange roughy since the inception of the fisheries in SEAFO CA.
There is no fishery data available since 2005 for Orange roughy within the SEAFO CA, as a result SC cannot conduct stock assessment of the Orange roughy stock within the Convention Area.
Management
Management unit: Yes
Management Advice
SC recommends a moratorium for 2017 and 2018 on directed fishery in Division B1 and allowance for bycatch limit as proportion (10%) of the average of landings from the last five years with positive catches (i.e. 2001-2005), equivalent to 4 tonnes.
The SC did not consider the allowance of a 50 tonnes TAC in the remainder of the area and cannot review the current status quo, due to a lack of new information.
A harvest control rule shall be developed for Orange roughy in the future as data becomes available.
In 2017 the SC reviewed the recommendation on Orange roughy but could not advice on the most appropriate harvesting level on this stock due to lack of scientific information. Historically, there were no records of landings higher than 22 tonnes outside B1. SC recommended a precautionary tac or bycatch allowance outside B1.
The annual catch and set TAC outside the B1 are shown in figure 4. There were no landing recorded since 2005.
 |
| Figure 4 Orange roughy catches and set TAC outside the B1 since 2005. |
Bibliography
Boyer, D.C., C.H. Kirchner, M.K. McAllister, A. Staby and B.I. Staalesen “The Orange Roughy Fishery of Namibia: Lessons to be learned about managing a developing Fishery. South African Journal of Marine Science, 23, 205-221.” 2001.
Branch, T.A. “A Review of Orange Roughy (Hoplostethus atlanticus) Fisheries, Estimation Methods, Biology and Stock Structure. Payne, A. I. L., S.C. Pillar & R.J.M. Crawford, eds. A Decade of Namibian Fisheries Science. South African Journal of Marine Science. 23:181 - 203.” 2001.
Anon “Social economic studies. Deepfishman. Case Study 1A Report. Namibian Orange Roghy. Institute of Economics Studies. University of Iceland.” 2010.
Anon “Capricon Fisheries Monitoring. State of Stock Review Report No. 2. In: Japp D.W., M.G. Purves and S. Wilkinson, Status of the Fishery Resources in the Benguela Current Large Marine Ecosystem. Cape Town.” 2011.
Anon “Ministry of Fisheries and Marine Resources. State of the Resource TAC recommendations report; Orange roughy. Namibia.” 2008.
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