This study is part of the PROACTIVA 1-2 (2009-2012) and MARPROF-CV (2010-2014) projects, in the
framework of the Canary Islands Government and UE PCT MAC 2007-2013 programmes respectively.
Research has mainly focused on the stock assessment of the striped soldier shrimp, Plesionika edwardsii
(Brandt, 1851), because it has shown moderate to high levels of fishing yield and abundances compatible
with the development of a new sustainable fishery in the Cape Verde Islands.
Cruises took place on board the R/V Prof. Ignacio Lozano. Four 15-day surveys have been conducted to
date: Cabo Verde 2010-04 (April 2010), Camar˜ao-1 (November 2011), Camar˜ao-2 (Mars 2012) and Camar
˜ao-3 (July 2012). An innovative fishing gear so-called multiple semi-floating shrimp trap (MSFST)
was used. Each fishing line was composed by 40-65 traps operating around 2.4 m above the seafloor,
using Decapterus macarellus (Carangidae) as unique bait of the traps. Fishing depth was 66-458 m, and
efective fishing time was 16-18 h. Each trap was attached to the main bottom line every 15 m, and the
maximum attraction of this bait was established to be 100 or 150 m, according to the experience gained
from the local fishery for deep-sea lobsters. So density by area was calculated assuming two different
areas of attraction of the fishing gear. Initial biomass was estimated from depletion experiments at different
abundance stations by applying the Leslie & Davis (1939) method, modified by Ricker (1975). Each
fishing operation was classified according to its yield (CPUE in g/trap/night). The potential fishing planar
area was estimated between the isobathymetric lines between 90 and 220 m. Total biomasses (Bt) were
calculated from areas (km2) and mean minimum/maximum densities (kg/km2). Maximum sustainable
yield (MSY) was estimated from Bt using the Beddington and Cooke (1983) model by entering natural
mortality (0.6), growth rate (0.53 year�1) and recruitment age (1.32 year), which are the parameters for
this target species published for the Canaries. These parameters estimate a biological exploitation rate
( ) of 0.262. Interpolations were applied to estimate MSY for insular stocks representing lesser than 5%
of the total fishing grounds for this species in the archipelago.
The MSY estimated by depletion were 30.5 tons/year for the stock of S˜ao Vicente, Santa Luzia, Ilheus
and S˜ao Nicolau, 10 tons/year for the stock of Santiago, 138.8 tons/year for the stock of Boa Vista
and Maio, and 5.6 tons/year for the stock of Sal. The small stocks estimated by interpolation were:
4.5 tons/year for the stock of Santo Ant˜ao, 1.3 tons/year for the stock of Fogo, and 1.8 tons/year for
the stock of Brava and Ilheus. In total, 192.5 tons per year was the total MSY for the striped soldier
shrimp around the islands of the Cape Verde archipelago, occupying a total area of 1,918 km2 of new
fishing grounds at between 90 and 220 m of depth. In comparison with the traditional bottom trap
used in the Canary Islands, the innovative fishing gear MSFST were proved to be more selective for
pandalid shrimps, minimizing the gear impact on the seafloor as well as the by-catch by reducing the
discards. Depletion methods are based on the assumption of a closed system, that is with minimum or
zero immigration between neighbouring areas. The straight forward decline of CPUEs obtained during
the depletion experiments seems to confirm that P. edwardsii is a low mobility species, making this
assumption valid at least during short-time periods. Because of the bathymetry profile of these islands,the depth range is from very close (few nautical miles in Santiago) to far away (10-12 n.m. in Boa Vista)
to the coastline.
Fishing effort should be controlled on the basis of quotas, number of fishing vessels and a precautionary
approach in order to ensure that catching is commensurate with sustainable levels of exploitation. MSY
estimates suggest that this new Capeverdean fishery should be carried out by specialized medium-sized
fishing vessels. During the last decades a combination of shrimp trawling and industrial trapping activity
has threatened over-exploitation in the Mediterranean fisheries targeting on P. edwardsii; currently the
shrimp collapse has conducted to the decline of these fisheries. Can the Cape Verde regulatory bodies
and all the stakeholders involved learn the lessons this teaches us about this resource management