Fisheries and Resources Monitoring System

Deep-water rose shrimp - Guinea-Bissau
Fact Sheet Title  Fact Sheet
CECAF Scientific advice 2020
Deep-water rose shrimp - Guinea-Bissau
Fact Sheet Citation  
Crevette rose du large (Parapenaeus longirostris) - Guinée-Bissau
Owned byFood and Agriculture Organization (FAO) – ownership
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Species List:
Species Ref: en - Deep-water rose shrimp, fr - Crevette rose du large, es - Gamba de altura, ar - إيربيان وردية أعماق المياه, zh - 长额拟对虾, ru - Креветка розовая глубоководная

Fishery Indicators
Production: Catch
ident Block Deep-water rose shrimp - Guinea-Bissau
Aq Res
Biological Stock: Yes         Value: National
Management unit: No        Reference year: 2016
Aq Res State Trend
Aq Res State Trend
Aq Res State Trend Aq Res State Trend
Aq Res State TrendFcur/F0.1 = 51%; Fcur/FMSY = 46%Not applicable
Aq Res State TrendBcur/B0.1 = 124% ; Bcur/BMSY = 137%Not applicable
Aq Res State Trend
Aq Res State TrendNot fully exploited

Fcur/F0.1: Ratio between the observed fishing mortality coefficient during the last year of the series and F0.1.
Fcur/FMSY: Ratio between the observed fishing mortality coefficient during the last year of the series and the coefficient that would give a maximum sustainable yield over the long term.
Bcur/B0.1: Ratio between the estimated biomass for the last year and the biomass corresponding to F0.1.
Bcur/BMSY: Ratio between the estimated biomass for the last year and the biomass corresponding to FMSY.
Unless otherwise indicated, the indicators were based on the Schaefer dynamic production stock assessment model.
Habitat Bio
Climatic Zone: Tropical.   Bottom Type: Soft bottom muddy or muddy-sand.   Depth Zone: Shelf - Edgeshelf; Slope (200 m - 1000 m).   Horizontal Dist: Neritic; Oceanic.   Vertical Dist: Demersal/Benthic.  

Geo Dist
Geo Dist: National

Water Area Overview
Spatial Scale: National

Water Area Overview
Aq Res Struct
Biological Stock: Yes

The Working Group adopted five stocks of Parapenaeus longirostris: the Guinea and Guinea-Bissau stock, the Sierra Leone stock, the Liberia stock, the Congo stock and the Angola stock. Although the Working Group considered a single stock for this species in Guinea-Bissau and Guinea, no new information from Guinea after 2007 is available due to the closure of the Spanish shrimper fishery, the one targeting this species in Guinea. This precludes the joint assessment and therefore, only the Guinea-Bissau stock can be assessed.

CATCH: Updated catch series of the deep-water rose shrimp P. longirostris were reported to the Working Group for the following fleets: Spanish shrimpers in Guinea-Bissau (1987-2016, with no fishery in 1997, 2013 and 2014), other shrimpers but Spanish in Guinea-Bissau (1990-2016, with no fishery in 1997 due to the Civil War), shrimpers in Nigeria (new data series from 2010 to 2016), shrimpers in Congo (1991-2016) and shrimpers and fish trawlers (both together) in Angola (1993-2016) (Table 6.4.3a). As the revision of the CIPA databases were done from 2000 onwards and the previous data are not completely reliable, the data series considered for the trend analysis of other shrimpers than Spanish in Guinea-Bissau is from 2000 to 2016. The new catch data provided by Nigeria comes from the separation of all the shrimp species caught by shrimpers in Nigeria, previously reported together. Other data series showed in Table 6.4.3a correspond to fisheries already closed, as it is the case of that for the Spanish P. longirostris shrimpers in Guinea (1995-2007), shrimpers and fish trawlers catching P. longirostris in Liberia (1997-2007), in Sierra Leona (2004-2007) and in Benin (1990-2004), and Spanish shrimpers in Angola (1987-2004).
-GUINEA-BISSAU- In Guinea-Bissau, at the beginning of the series, the catch of P. longirostris from the Spanish fleet was the highest in its EEZ (around an average value of 900 tonnes in the period 1990-1995). The Spanish catch diminished with time, while the one from the other shrimper fleets fishing in Guinea-Bissau increased, remaining higher than the Spanish most the years in the period 1996-2006 (average values of around 800 tonnes versus 400 tonnes). Oppositely, Spanish catches were much higher than those from other fleets from 2007 to 2012 (average of 759 tonnes versus 89 tonnes), when the fleet left the fishing ground to the cease of the FPA between the EU and Guinea-Bissau during a period of two and a half years. Catches after the restarting of this fishery in 2015 remained at levels of the average in the period 2007-2012, before the cease of the fishery, dropping in the last year to 331 tonnes, similar value that the one obtained by the other shrimper fleets in the area. It should be noted that the data revision of the foreign shrimper fleets other than Spanish from the CIPA databases is for the period 2000-2016 and therefore, data before this period are less reliable.
FISHING EFFORT: The effort data series for P. longirostris updated for this Working Group cover Guinea-Bissau (effort of the Spanish fleet from 1987 to 2016, and of the other foreign shrimpers from 1990 to 2016), Congo (shrimper trawlers 1991–2016) and Angola (shrimper trawlers in 1993-2016) (Table 6.4.3b). It should be noted that a new estimation of specific effort on P. longirostris from the Spanish fleet was provided to the Working Group for the period 1999-2016. In addition, the revision of CIPA databases allowed calculating effort as fishing days with positive catches of P. longirostris for the shrimper fleets other than Spanish in Guinea-Bissau and for the period 2000-2016. This new effort series are the ones used for analysis by the Working Group.
The effort deployed by the Angolan shrimpers is by far, the biggest in the region, followed by the Spanish shrimpers in Guinea-Bissau and by the shrimpers in Congo, in alternate periods. The effort in Angola has generally increased since 2009 to values around 12 500 fishing days in 2016. The maximal effort of the Spanish shrimper fleet in Guinea-Bissau was deployed in 2009 (around 3 700 fishing days), to progressively decrease until the cease of the activity in 2013 and 2014. After reentering in the fishing ground, the Spanish fleet kept a low activity level, with an effort of around 700 fishing days in 2016. The effort of other shrimper fleets in Guinea-Bissau oscillated during the first period (2000-2007) of the series analyzed around an average value of 1 300 fishing days, to subsequently decrease during the period 2008-2011 to average values of 100 fishing days, newly increase up to a peak of 1 300 fishing days in 2014 and finally decrease in 2016. The effort of shrimpers in Congo shows an increasing trend until reaching a maximum of around 2 000 days at sea in 2013, decreasing after this year.
CPUE: The CPUE series considered (Table 6.4.3b) are from the fleets operating off Guinea-Bissau, Congo and Angola, described above. Trends are shown in Figure 6.4.3b. Only general trends can be compared from one fleet to another. The CPUE values are not comparable due to the different units used (kg/fishing day or kg/days at sea) or to the different methods of effort estimations used for the CPUE calculations.
- GUINEA-BISSAU - The CPUE of P. longirostris from non-Spanish shrimper trawlers was changed from last Working Group, based on the catch and effort data corrections in the CIPA database and the new estimation of effort as fishing days with positive catches of the species. The data corrected are for the period 2000 to 2016. This CPUE shows the typical fluctuating trend of short living species (Figure 6.4.3b), with an average value around 450 kg/fishing day during the period 2000-2009. The CPUE then dropped to a minimum of 243 kg/fishing day in 2010, to progressively increase up to a maximum value of 822 kg/fishing day in 2013, followed by a new decrease in 2014 and 2015 and stabilization in 2016 (475 kg/fishing day).
The CPUE of P. longirostris from the Spanish fleet in Guinea-Bissau was also changed from the last Working Group, due to the new estimation of specific effort targeting this species, for the period 1999-2016 (Figure 6.4.3b). It should be noted that this CPUE can be considered as a good proxy of the abundance of the deep-water rose shrimp, as the Spanish fleet is very specialized in the fishery of this species. The CPUEs more or less follow a similar trend than to the one of the other shrimpers in Guinea-Bissau, with the exception of certain years. No data are available for 2013 and 2014 due to the closure of the EU fishery in Guinea-Bissau during this period. The average value of all the data series considered is 331 kg/fishing day, with a minimum value of 194 kg/fishing day in 2006 and maximal values around 460 kg/fishing day in the last two years of the series, after the reentering of the fleet in the fishing ground.
Fishery Indicators
TypeMeasureValueUnitTime period
ProductionCatch 1768tonnes1990
Catch 992tonnes1991
Catch 1145tonnes1992
Catch 921tonnes1993
Catch 1105tonnes1994
Catch 1073tonnes1995
Catch 1472tonnes1996
Catch 1297tonnes1997
Catch 39tonnes1998
Catch 473tonnes1999
Catch 1128tonnes2000
Catch 1712tonnes2001
Catch 839tonnes2002
Catch 1544tonnes2003
Catch 1074tonnes2004
Catch 762tonnes2005
Catch 924tonnes2006
Catch 816tonnes2007
Catch 977tonnes2008
Catch 1154tonnes2009
Catch 848tonnes2010
Catch 839tonnes2011
Catch 683tonnes2012
Catch 483tonnes2013
Catch 892tonnes2014
Catch 1306tonnes2015
Catch 673tonnes2016
Bio Assess

Assessment year: 2017
The CECAF Working Groups have adopted the following Biological Reference Points (BRPs):
- Limit Reference points: BMSY and FMSY
- Target Reference Points: B0.1 and F0.1
Stock status is assigned based on current estimates of fishing mortality (Fcur) and biomass (Bcur) relative to these target and limit reference points (Bcur/BMSY, Fcur/FMSY, Bcur/B0.1, Fcur/F0.1). The results from the stock assessment of this stock are found under the “Biological state and trend section”.

For the catch series, data from all the shrimper fleets operating off Guinea-Bissau were used, between 1999 and 2010. The Working Group decided to use the CPUE series of the Spanish shrimpers’ fleet, as it is the one better reflecting the abundance of the species, due to the fact that this fleet mainly targets P. longirostris. In addition, this CPUE was calculated with the specific effort targeting this species. The times series used were shorter than in the previous assessment, as data from other catches than Spanish coming from CIPA are more reliable since 2000, first year of the CIPA database review and correction. The initial values for the model are: r = 1.00 per year, K = 4000 tonnes and BI/K = 60 percent. The value of the stock intrinsic growth rate (r) was changed in relation of that used in the last assessment, as it was considered more in agreement to the r value of this stock. A second trial was carried out using the CPUE of other shrimper fleets operating in the area, estimated from effort as fishing days with positive caches of P. longirostris. In this case, the time series used was from 2000 to 2016.
Assess Models
Type:  Biomass-aggregated
Schaefer dynamic production model

The Schaefer dynamic production model was used by the Working Group to evaluate the state of the stocks and the demersal fisheries in the region. The model is described in detail in FAO, 2012.

RESULTS: The fit of both models were good and showed the same situation. The Working Group accepted the one using the Spanish CPUE, as the fit was better. The current fishing mortality (Fcur) is below the level that can produce the target biomass (F0.1) while the current biomass (Bcur) is higher than the target biomass B0.1 (Table 6.4.4a and Figure 6.4.4a).
DISCUSSION: The results indicate that the stock is not fully exploited. These results are very similar to those obtained in the last assessment in 2011 and also consistent with the Spanish CPUE trend. In addition, a slight improvement in biomass was noted, probably due to the reduction of the fishing mortality caused by the ceasing of EU fishery from June 2012 to December 2014, followed by an effort reduction when reentering to the area in 2015.
Sci Advice

According to the assessments the Working Group considers the stock could sustain a controlled increase in catch adjusted to the level of the mean of the last five years (800 tonnes) (FAO, 2020).
Management unit: No
FAO. 2019. Report of the FAO/CECAF Working Group on the Assessment of Demersal Resources – Subgroup South. Libreville, Gabon, 6–15 September 2017/Rapport du Groupe de travail sur l’évaluation des ressources démersales – Sous-groupe Sud. Libreville, Gabon, 6–15 septembre 2017. CECAF/ECAF series/ FAO/COPACE COPACE/PACE séries no.18/79. Rome.  Click to open
FAO. 2019. Fishery Committee for the Eastern Central Atlantic, Report of the eighth session of the Scientific Sub-Committee, Abidjan, Côte d’Ivoire, 23–26 October 2018 / Comité des pêches pour l’Atlantique Centre-Est Rapport de la huitième session du Sous-Comité scientifique, Abidjan, Côte d’Ivoire, 23–26 octobre 2018. FAO Fisheries and Aquaculture Report / FAO Rapport sur les pêches et l’aquaculture No. 1265. Rome.  Click to open
FAO. 2020. Report of the Twenty-Second Session of the Fishery Committee for the Eastern Central Atlantic, Libreville, Gabon, 17–19 September 2019. Rapport de la vingt-deuxième session du comité des pêches pour l’Atlantique centre-est, Libreville, Gabon, 17–19 septembre 2019. FAO Fisheries and Aquaculture Report / FAO, Rapport sur les pêches et l’aquaculture No. 1303. Rome.  Click to open
All references to figures, tables and bibliography in the text are found within the source of information.
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