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UNION ECONOMIQUE ET MONETAIRE MARINE FISHERIES RESEARCH
OUEST AFRICAINE DIVISION - GHANA (MFRD)
SURVEY OF THE PELAGIC FISH RESOURCES OFF GHANA
13 March – 17 March 2012
Marine Fisheries Research Division, Tema,Ghana
Centre de Recherches Océanographiques (CRO), Dakar, Sénégal
R.V. ITAF DEMÉ– CRO, Senegal
Roche ltée, Groupe-conseil
3075, chemin des Quatre-Bourgeois, bur. 3
Québec (Québec) Canada G1W 4Y4
1
DRAFT FINAL REPORT OF EUMOA SPONSORED
SURVEY OF THE PELAGIC FISH RESOURCES OFF GHANA
13TH – 17TH MARCH, 2012
by
RichmondQuartey*
Ebenezer Ekuban*
AbdoulayeSaaré**
*Marine Fisheries Research Division, Tema, Ghana
and
** Centre de Recherches Océanographiques de Dakar - Thiaroye, Dakar, Sénégal
2
TABLE OF CONTENTS:
1 INTRODUCTION…………………………………………………..3
1.1 OBJECTIVES OF THE CRUISE………………………………4
1.2 PARTICIPANTS…………………………………………………4
1.3 NARRATIVE……………………………………………………..5
2 METHODS………………………………………………………….7
2.1 ENVIRONMENTAL DATA…………………………………….7
2.2 BIOLOGICAL SAMPLING…………………………………….8
2.3 ACOUSTICS SAMPLING……………………………………..9
3 SURVEY RESULTS………………………………………………11
3.1 HYDRGRAPHIC CONDITIONS
3.1.1 Salinity hydrographical profiles……………………………..11
3.1.2 Temperature…………………………………………………..12
3.2 PELAGIC FISH…………………………………………………….13
4 OVER VIEW OF RESULTS…………………………………………18
Annex I List of Participants
Annex II Fishing Operations
Annex III Instruments and Fishing Gear Used
Annex IV Number and Biomass of Main Species
Annex V Size Frequency of Main Species
Annex VII List of Participants
3
1 INTRODUCTION
The survey was organized by the Centre de Recherché Océanographiques of Dakar and
sponsored by the Economic and Monetary Union of West Africa, UEMOA, under the
International program of cooperation within the West African States on agriculture (No Act
03/2001). N°05/2007/CM/UEMOA 2007. This project is the first of a series of projects and
agreements between EUMOA involving surveys with the research vessel “R.V ITAF DEME”. The
objectives of the survey had been agreed upon during discussions between the EUMOA and the
Ghana government through the Fisheries Commission under the Ministry of Food and
Agriculture and the Environmental Protection Agency (EPA) in Ghana.
The broad agricultural policy of the Economic Union of West African States is towards the
regional project for assessment of fish stocks. The guidelines of the agricultural policy of the
UEMOA (PAU) were adopted in December 2001 by the Conference of Heads of State and
Government of UEMOA, through the additional Act 03/2001. The fisheries sector was addressed
specifically in axis 2 of the PAU: "deepening of the common market in the agricultural sector and
management of shared resources.
Under the Agricultural Policy of UEMOA (PAU), a three year program was adopted in Dakar in
March 2003 to develop the fisheries sector in the UEMOA which aims to establish a process of
coordinating and harmonizing management of shared fisheries resources, for sustainable
management of these resources and to contribute to food security and poverty reduction in the
UEMOA. This program includes, among others, the definition of a plan of concerted
development of fisheries and aquaculture within the UEMOA underpinned by good knowledge of
the state of fisheries resources in the UEMOA countries. The objective of this program is to
establish a process of coordination and harmonization of the management of shared fisheries
resources for sustainable management of these resources and contribute to food security and
poverty reduction in the UEMOA area. This program consists of five (05) components namely:
the creation of the Advisory Committee on the harmonization of policies and the laws of the
Member States concerning fishing and aquaculture. The definition of a concerted plan of
fisheries and aquaculture in UEMOA is a regional strategy of negotiation of the fisheries within
the UEMOA agreements.
This Project aims at improving and strengthening the knowledge of the stocks of the member
states of the Union, by collecting the appropriate scientific data, to set coherent and effective
measures of arrangement, in the optics of a responsible fishing. It will also create continuity
4
along the African West coast and meet the need to have the best information on the stock of the
region, etc.
1.1 Objectives
Following the agreement between UEMOA and the CRO, the main objectives of the survey
were:
To estimate the biomass and map the distribution of small pelagic fish stocks off Ghana by
hydro-acoustic methods and describe the hydrographic conditions in the region over a period
of 6 days, from March 13 - 17, 2012.
To map the general hydrographic regime and to monitor the temperature, salinity at deep
water trawl stations and on hydrographical stations
Collect biological data of the main target species
To sample standard hydrographical transects for temperature, salinity and oxygen.
On the job training for local participants covering main survey routines
1.2 Participation
Participating scientists from Ghana boarded the vessel at Takoradi on the 13th of March 2012 to
join the scientists and crew of the N/O Itaf Deme.
List of scientific participants:
From: Centre de Recherches Océanographiques de Dakar-Thiaroye (CRODT), Sénégal:
Abdoulaye Sarre (Cruise leader) and Ndiaga Thiam (Fisheries biologist)
From: The Marine Fisheries Research Division, Tema, Ghana:
Richmond Quartey and Ebenezer Ekuban
1.3 Narrative
5
The survey started on the 13 March 2012 at 12:30 GMT (GMT=Local time) from Takoradi. The
vessel departed and steamed east towards Lomé at the border with Togo, where the trip ended
on the 17 March 2012.
After the disembarkation of the Ivoirians, the ship loaded Mr. Quartey and Mr. Ekuban of Ghana,
the campaign of Ghana began in the morning of March 13th and all zones were covered from
13th till 17th March.
In total, 13 transects were canvassed; 41 hydrologic stations were visited. In every region (West,
Centre and East of Ghana) measurements of current meters were performed.
The acoustical index of cogitation was recorded continuously with SIMRAD SOUNDER ER60.
The fishing operations were performed according to the detections; type of trawl-net used was
dependent on the location of these detections (at the surface or at the bottom); parallel course
tracks (acoustic transects) about 10 NM (nautical miles) apart. During this season, detections
were rare on the mid water casts. On the contrary, significant detections were regularly recorded
on demersal casts. In total 12 throws of trawl-net were performed, 5 with the mid water trawl and
7 with the demersal trawl-net.
During the survey semi-random swept-area hauls were carried out on the shelf within the depth
zones 20-30m, 31–50m, and 51-100m during daytime. Continuous acoustic registrations were
done throughout the survey. Pelagic trawling on registrations and random trawl hauls were taken
irregularly but with the aim of covering representative areas of the shelf between 20 and 100m
depth. Trawling was done irregularly either to identify echo registrations or to check ‘blindly’ if
fish were mixed with the plankton in the upper layers of the water column. Pelagic trawl with
floats was often used to catch fish close to the surface. A smaller pelagic trawl or the bottom
trawl with floats was used for sampling pelagic fish in shallow waters (depth less than 25metres).
1.4 Survey Efforts
Figure 1 shows the cruise tracks with trawl and hydrographic stations for the Ghanaian region.
6
Fig. 1 Cruise Tracks of Ghana Survey
Table1.1 Survey area and valid trawl stations by depth stratum, total trawl stations separated by
bottom (BT) and pelagic (PT), hydrographic stations (CTD) and distance surveyed in NM.
Summary of Survey Effort
Table 1.1 Survey Areas and Trawl Station
2. METHODOLOGY
2.1 Meteorological and hydrographical sampling
Area BT PT CTD Dist. Surveyed
Ghana 7 5 41 706 NM
7
Temperature, salinity, and oxygen sampling
CTD were taken in connection with most trawl stations and at predetermined hydrographic
transects. Figure 1 presents positions for CTD stations. A Seabird 911 CTD plus was used to
obtain vertical profiles of temperature, salinity and oxygen. Real time plotting and logging was
done using the Seabird Seasave software installed on a PC. The profiles were usually taken
down to a few meters above the bottom. The calibration constant calculated during surveys off
the western Gulf of Guinea was applied for the whole survey.
Thermosalinograph
The ES38B thermosalinograph run routinely during the survey. It continuously obtained
samples of sea surface salinity and relative temperature (5 m depth) every 10 sec during the
survey.
Current speed and direction measurement (Aanderaa)
The ship-borne Acoustic Doppler Current Profiler (Aanderaa) run throughout the survey. The
Aanderaa was set to external trigger by the Simrad ER 60 acoustic system. The depth cell
interval set to 8m and the number of cells set to 50.
Meteorological
Wind direction and speed, air temperature, global radiation and sea surface temperature (5m
depth) were logged automatically every nautical mile on an Aanderaa meteorological station.
The environmental data collection was performed using a CTD brand ALEC model AST 1000.
Measurements were taken from 41 stations on the 13-transect coverage area. On the 7th
transect temperature and salinity was taken at 10, 50 and 100 meters depths. Transects 2, 5
and 6 were sampled at 10, 25, 50, 100, and 200 meters depth.
8
2.2 Biological fish sampling
The pelagic trawl catches were sampled for species composition by weight and numbers. The
deck sampling procedure is described in more detail by StrØmme (1992). The length
measurement (total length) was taken for target species. The length of each fish was recorded to
the nearest 1 cm below, and for anchovy to the nearest 1 mm below. The mantle length was
measured to the nearest 1 cm below for Sepia spp. In addition, at a few stations total length and
body weight (g) were recorded for the target species in the acoustic survey. Basic information
recorded at each fishing station i.e. trawl hauls, is presented in Annex II. A description of gear
used, acoustic instruments and their standard settings is in Annex III. The swept-area estimates
are presented in Annex IV. Pooled length frequency distributions, raised to catch per hour, of
selected species by area are shown in Annex V. Groups families included in the species
composition and swept area analysis is given in Annex VI. Fishing operations were performed
using a pelagic trawl, and a mid-water trawl employing big floats. These operations were carried
out according to the importance of concentrations encountered. Thus 12 hauls were made in
total, with 7 midwater trawls and 5 pelagic trawls. At each station, a representative sample was
taken to determine the composition, weight and number by species, size frequency for the target
species.
The length-weight relationship used to estimate biomass is:
W = L3 * condition factor (cond)
100
Where a condition factor (cond) =
0.94 was used for round sardinella,
0.97 for flat sardinella, 0.96 and
0.88 for mackerel for Carangidae, Clupeidae and associated species. with an average
size of 23 cm was used for the evaluation biomass.
2.3 Biomass Estimates
Acoustic abundance estimation
A SIMRAD ER 60 Echo sounder was used and the echograms were stored on files. The
acoustic biomass estimates were based on the integration techniques. The large scale Survey
system (LSSS, Christian Michelsen Research Center) was used for integration, analysis and
9
allocation of the integrated SA-values (average area back scattering coefficient in m2/NM2). The
splitting and allocation of the integrator outputs (SA-values) was based on a combination of a
visual scrutiny of the behavior pattern as deduced from echo diagrams, LSSS analysis and the
catch composition. The mean integrator value in each sampling unit (SA-values) was divided
between the standard categories / groups of fish, as noted below, on the basis of trawl catches
and characteristics of echo traces.
-Sardinella (Sardinella aurita and S. maderansis)
-PEL 1 (clupeids other than sardinella)
-PEL 2 (carangids, scombrids, barracudas, hairtail)
-Mesopelagic fish
-Demersal fish
-Plankton
The following target strength (TS) function was applied to counter sA-values (mean integrator
value for a given area) to number of fish (sardinella, PEL 2):
TS = 20 log L – 72 dB (1)
Or in the form
CF = 1.26 – 106 –L-2 (2)
Where L is total length CF is the reciprocal back scattering strength, or the so-called fish
conversion factor. In order to split and convert the allocated sA-values (m2/NM2) to fish densities
(number per length group per NM2) the following formula was used
Where ρi= number of fish in length group i
(3)
iA i
i
Fi
nSp
p
Ci
1
10
A = area (NM2) of fish concentration
SA = mean integrator value (echo density) in area A (m2/NM2)
Pi = proportion of fish in length group I in sample from the area
CFi = fish conversion factor for length group i
The number per length group (ρi) was then summed and the total number of fish obtained:
ρ = ∑n ρ i
i=1 (4)
The length distribution of a given species within an area was computed by simple adding of the
length frequencies obtained in the pelagic trawl samples within the area. In the case of co-
occurrence of target species, the SA value was split in accordance with length distribution and
catch rate in numbers in the trawl catches. Biomass per length group (Bi) was estimated by
applying measured weights by length (W i) when available or theoretical weights (calculated by
using condition factors), multiplied with number of fish in the same length group (Ni). The total
biomass in each area was obtained by summing the biomass of each length group:
B =∑n ρ WI
i=1
The number and biomass per length group in each concentration were then added up to obtain
totals for each region.
11
3 SURVEY RESULTS
3.1 Hydrography
Hydrographical data was collected on fixed CTD stations from the Thermosalinograph and the
Aanderaa weather station that continuously collected sea surface temperature, wind speed and
direction, solar radiation, etc. during the survey.
The section worked here show a stable stratified distribution of the oceanographic parameters,
Surface salinity was between 34.2 and 34.85 0/00 with strong salinity gradient being found in the
central and western part of the shelf as shown in figure 3.1.
Fig. 3.1 Sea Surface salinity on Ghana shelf
12
Temperature
Sea surface temperatures were dominated by water temperatures higher than 29oC for the
entire shelf of Ghana at the surface figure 3.
2
Fig. 3.2 Spatial Distribution of Temperature-Ghana
Fig. 3.3 Vertical sections of temperature off Tema
13
4. RESULTS FROM THE ACOUSTIC SURVEY
The distribution area of the main groups of pelagic fish on the shelf off Ghana, i.e. the
sardinellas, Horse, PEL 1 (Clupeids), and PEL 2 (mainly carangids), are depicted in the following
figures (4.1 – 4.6) using the integrator values from the LSSS echo-integrator system recorded
with the ES38B kHz transducer connected to the ER60. The acoustic densities (in m2NM2) are
illustrated by a scale normally used on acoustic surveys with “Dr. Fridtjof Nansen”.
Ghana shelf
The hydro acoustic survey of Ghana section covered the shelf and slope systematically to 100m
depth during the day time, continuing offshore during the night hours. Due to lack of time and
sea conditions, we could not repeat areas where the acoustic densities were weak at night.
However, the coast of Ghana was properly covered so as to estimate its pelagic biomass. Low
to medium acoustic densities was found over most of the shelf.
Pelagic Fish
The main groups of pelagic fish encountered during the survey of Ghana illustrated with
contoured acoustic densities are shown in Figure 4.1 – 4.6
Sardinella and Achovy
Sardinella maderensis was the prominent species in this group encountered, figure 4.1, and
accounted for 81% of the total sardinella catch in this sub region.
Fig. 4.1 Distribution of S. maderensis
14
Length distribution for this group was between 6cm and 9cm for both species. However very
small densities of S. aurita were encountered only at the western end of Ghana around Cape
Three point, figure 4.2.
Fig. 4.2 Distribution of S. aurita in Ghana
Table 4.1 shows that the total biomass estimates for the main groups encountered during the
survey.
MAIN GROUPS BIOMASS ESTIMATES (TONS)
S. maderensis 4550
S. aurita 1070
Anchovy 1530
Horse 8940
PEL 1 460
PEL 2 23790
Table 4.1 Biomass Estimates of the Survey
15
However a few anchovies were caught on this expedition just beyond the 30 m depth contour, as
shown in figure 4.3, with length distribution ranging from 6 cm to 8 cm and a total biomass
estimate of 1530 tons.
Fig.4.3 Distribution and concentration of anchovy in Ghana
Horse Group
D.macarellus was the most dominant species for the Horse group. It was distributed widely both
in the eastern and western portions of the shelf, figure 4.4.
Fig. 4.4 Distribution and abundance of Horse in Ghana
16
Their distribution was not so dense and to a large extent are mostly juveniles. Length distribution
for this group ranged from a minimum of 2cm to a maximum of 28cm. Assuming an average
length of 7cm for the two groups with a condition factor of 0.96, the biomass estimate of Horse is
8 940 tons.
PEL 1
Only one member of this group was encountered during this survey. Decapterus punctatus was
encountered in the inner portion of the shelf in small quantity (fig. 4.5). Assuming an average
length of 7 cm and a condition factor of 0.96 the biomass estimate of PEL 1 was 460 tons (Table
4.1)
Fig. 4.5 Distribution and abundance for PEL 1-Ghana
PEL 2
This group was encountered in both the central portion and the western part of the shelf in wide
patches (fig 4.6). Among the carangids D. macerate was the most prominent of this group in
terms of number of occurrences. It was distributed in the inshore area within the 30 m to 50 m
depth range. Within this range also a few juvenile D. punctatus were encountered with some
medium size Moon fish, Selene dorsalis, also showing up. However, the biggest carangid
17
present in this survey was Alectis alexandrenus which gave the highest weight caught in the
entire survey. The main species widely distributed in this group is D. macerate which was caught
at two different depth ranges. The length distribution of the species is found in Annex. Assuming
an average total length of 13cm for all the species and a measured condition factor of 0.96 the
biomass estimate of PEL 2 was estimated to about 7 840 tons (Table 4.1).
Fig. 4.6 Distribution and abundance of PEL 2-Ghana
18
General Over View
The biomass estimated in this work is in many respects comparable to estimates from other
previous surveys in Ghana with regards to the methodology. Any differences may be due to the
fact that all surveys have either been limited in time or restricted in area, which could lead to
overestimation or underestimation. Recruitment could possibly have changed also, with the
pelagic species whose abundance is usually linked to favorable environmental parameters. It is
likely that recent high average SST may have had an impact on the lower estimates achieved in
this survey, in addition to this survey being a short one (7 days).
However, it is going to be difficult to relate results from this survey with any previous surveys for
the simple reason that we have no records of any acoustic surveys in the Ghanaian waters in
March. The pelagic stocks are usually seasonal, and in this survey they were found mostly in
waters between the 40m to 50m depths; revealing high concentrations of Sardinella
maderensis and S. auritas and anchovies. The average length registered for these three pelagic
species was ranges from 7 – 9 cm; indicating that they are mostly juveniles yet to be recruited to
the fisheries.
The distribution pattern for the pelagic resources encountered in this survey was also noteworthy
for the time of the year. The anchovies encountered were in one cluster, and the same goes for
the S. aurita and the PEL 1. And these were found in smaller concentrations ranging between
0.46 to 1.07 x 103 tons.
However, the situation is very different for the S. maderensis, Horse and PEL 2. These were all
encountered in two different concentrations; there was an eastern group and a western group,
except for Horse, that was found in the Central part of the shelf and to the west of the shelf. For
S. maderensis, the Central concentration was greater than the Western concentration (2.56 to
1.99) x103 tons; whereas for PEL2, the Western concentration was greater than the Central
concentration (20.3 to 3.45) x 103 tons. For Horse, the concentration was found in the Eastern
and the Central parts of the shelf, with the Eastern having the greater weight i.e. 7.84 to 1.10 x
103 tons.
The depth at which these pelagic species were encountered indicate that they are not yet ready
to be recruited to the artisanal fisheries since their range extends beyond the 30 m depth
contour for artisanal fisheries, and also their sizes indicate that they are juveniles except ,
perhaps, for the anchovies.
19
REFERENCES
Toresen, R., Gjøsæter, H., and Barros, P. 1998. The acoustic method as used in the
abundance estimation of capelin (Mallotusvillosus Müller) and herring (Clupeaharengus
Linné) in the Barents Sea. Fisheries Research 34 (1998) 27-37.
MacLennan, D. N. and Simmons E. J. (1992). Fisheries Acoustics. Chapman and Hall.325p.
20
ANNEX I List of Participants in the Campaign
Name Function Period
Abdoulaye SARRE Coordonnateur du navire From 2 to 31 March
Ndiaga THIAM Biologiste From 2 to 31 March
Mor SYLLAResponsable collecte
biologiqueFrom 2 to 31 March
Cheikh NDOURResponsable collecte
environnementaleFrom 2 to 31 March
Amadou Fallou NIANG Biologist From 2 to 31 March
Madiabel DIOP Biologist From 2 to 31 March
Richmond QUARTEY Biologist /Ghana From March 13 to 17
Ebenezer EKUBAN Biologist /Ghana From March 13 to 17
Karim Moulaye MARA commander: From 2 to 31 March
Arfang SARR Shift Supervisor From 2 to 31 March
Abdourahmane SARR Chief Engineer From 2 to 31 March
Youssou SAMB Lieutenant Fishing From 2 to 31 March
Ousseynou Faye crew From 2 to 31 March
Alassane Séne crew From 2 to 31 March
OusseynouNdiaye crew From 2 to 31 March
Mamadou Niang crew From 2 to 31 March
AdamaSy crew From 2 to 31 March
LansanaDiedhiou crew From 2 to 31 March
Mamadou NIASSY crew From 2 to 31 March
Serigne Lo crew From 2 to 31 March
Saliou Ba crew From 2 to 31 March
Abdoulaye M’Bengue crew From 2 to 31 March
Moussa Thiandoum crew From 2 to 31 March
Mbaye N’Diaye crew From 2 to 31 March
Idrissa Diémé crew From 2 to 31 March
21
ANNEX II Results Fishing Operations - GHANA
ItafDeme SURVEY:2120301 STATION 12
DATE :13/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 4ー53
start stop duration Lon W 2ー25
TIME :23:20:00 23:50:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 30 32 Validity : 0
Towing dir: 0ー Wire out : 50 Speed : 2.5 kn
Sorted : 4 Total catch: 4.06 Catch/hour: 8.12
SPECIES CATCH/HOUR% OF TOT
C SAMP
weight numbers
Engraulisencrasicolus 6 1800 73.89 14
Sardinellaaurita 0.6 126 7.39 13
Sepia sp. 0.4 38 4.93
Sardinellamaderensis 0.4 8 4.93
Caranxlatus 0.2 2 2.46
Decapterusmacarellus 0.2 4 2.46
Alloteuthisafricana 0.2 24 2.46
Elagatisbipinnulata 0.1 2 1.23
Sauridabrasiliensis 0.02 2 0.25
__________ ________
Total 8.12 100
ItafDeme SURVEY:2120301 STATION 13
DATE :14/03/2012 GEAR TYPE: BT NO: 1POSITIONlat N 4ー57
start stop duration Lon W 1ー33
TIME :16:20:00 16:50:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 21 20 Validity : 0
Towing dir: 0ー Wire out : 100 Speed : 3.2 kn
Sorted : 66 Total catch: 65.7 Catch/hour: 131.4
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Brachydeuterusauritus 50 2294 38.05 15
Chloroscombruschrysurus 20 834 15.22
Polydactylusquadrifilis 18 2 13.7
Sphyraenaguachancho 8 130 6.09
Pomadasysperoteti 6 2 4.57
Drepaneafricana 5.6 62 4.26
22
Selene dorsalis 5.4 540 4.11
Galeoidesdecadactylus 4 74 3.04
Trichiuruslepturus 3.8 2 2.89
Pseudotolithustypus 2 22 1.52
Ethmalosafimbriata 1.6 16 1.22
Pseudotolithusbrachygnathus 1.2 2 0.91
Panulirusregius 0.9 6 0.68
Elopslacerta 0.8 2 0.61
Alectisalexandrinus 0.7 8 0.53
Ephippionguttifer 0.6 2 0.46
Callinectes sp. 0.6 4 0.46
Ilishaafricana 0.6 16 0.46
Dentexcanariensis 0.5 2 0.38
Cynoglossussenegalensis 0.4 4 0.3
Lagocephaluslaevigatus 0.3 6 0.23
Pteroscionpeli 0.3 16 0.23
Sardinellamaderensis 0.1 6 0.08
__________ ________
Total 131.4 100
ItafDeme SURVEY:2120301 STATION 14
DATE :14/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 4ー49
start stop duration Lon W 1ー28
TIME :19:20:00 19:50:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 38 37 Validity : 0
Towing dir: 0ー Wire out : 50 Speed : 3.1 kn
Sorted : 1 Total catch: 1.06 Catch/hour: 2.12
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Decapterusmacarellus 1 14 47.17
Balistescapriscus 1 8 47.17
EXOCOETIDAE 0.1 2 4.72
Caranxlatus 0.02 4 0.94
__________ ________
Total 2.12 100
ItafDeme SURVEY:2120301 STATION 15
DATE :15/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 4ー29
start stop duration Lon W 1ー8.
TIME :05:45:00 06:15:00 30.0 (min) Purpose : 1
23
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 60 58 Validity : 0
Towing dir: 0ー Wire out : 100 Speed : 2.9 kn
Sorted : 0 Total catch: 0.26 Catch/hour: 0.52
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Decapterusmacarellus 0.1 94 19.23 17
Diodonhystrix 0.4 8 76.92
Caranxlatus 0.02 4 3.85
__________ ________
0.52 100
ItafDeme SURVEY:2120301 STATION 16
DATE :15/03/2012 GEAR TYPE: BT NO: 1POSITIONlat N 4ー47
start stop duration Lon W 1ー8.
TIME :09:40:00 10:10:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 41 43 Validity : 0
Towing dir: 0ー Wire out : 150 Speed : 3.2 kn
Sorted : 80 Total catch: 80.4 Catch/hour: 160.98
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Lutjanusfulgens 50 146 31.06
Pagruscaeruleostictus 23 52 14.29
Lethrinusatlanticus 23 78 14.29
Pseudupeneusprayensis 16.4 382 10.19
Dentexcanariensis 13.8 18 8.57
Chromis sp. 9 164 5.59
Acanthostracionquadricornis 8.2 30 5.09
Acanthurusmonroviae 4.4 12 2.73
Epinephelusaeneus 2.2 2 1.37
Apsilusfuscus 2 32 1.24
Dasyatischrysonota 1.8 2 1.12
Balistespunctatus 1.4 2 0.87
Bodianusspeciosus 1.2 2 0.75
Lagocephaluslaevigatus 1 2 0.62
Aluteruspunctata 0.8 4 0.5
Syaciummicrurum 0.8 8 0.5
Pagellusbellottii 0.6 2 0.37
Chaetodonhoefleri 0.5 4 0.31
Fistulariatabacaria 0.4 6 0.25
24
Trachinocephalusmyops 0.4 4 0.25
Xyrichtysnovacula 0.04 4 0.02
Priacanthusarenatus 0.04 2 0.02
__________ ________
Total 160.98 100
ItafDeme SURVEY:2120301 STATION 17
DATE :15/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 5ー3.
start stop duration Lon W 0ー50
TIME :16:25:00 16:55:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 29 29 Validity : 0
Towing dir: 0ー Wire out : 50 Speed : 3.0 kn
Sorted : 0 Total catch: 0.37 Catch/hour: 0.74
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Decapterusmacarellus 0.1 18 13.51 17
Euleptorhamphusvelox 0.5 4 67.57
Aluteruspunctata 0.02 2 2.7
Psenes sp. 0.02 2 2.7
Caranxlatus 0.1 6 13.51
__________ ________
0.74 100
ItafDeme SURVEY:2120301 STATION 18
DATE :16/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 5ー12
start stop duration Lon W 0ー30
TIME :03:55:00 04:25:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 35 35 Validity : 0
Towing dir: 0ー Wire out : 50 Speed : 2.8 kn
Sorted : 0 Total catch: 0.27 Catch/hour: 0.54
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
25
Caranxlatus 0.002 2 0
Decapterusmacarellus 0.02 32 3.7 18
Selene dorsalis 0.02 2 3.7
Caranxcrysos 0.5 2 92.59
__________ ________
0.54 100
ItafDeme SURVEY:2120301 STATION 19
DATE :16/03/2012 GEAR TYPE: BT NO: 1POSITIONlat N 5ー12
start stop duration Lon W 0ー29
TIME :05:05:00 05:35:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 35 35 Validity : 0
Towing dir: 0ー Wire out : 100 Speed : 2.9 kn
Sorted : 0 Total catch: 0.00 Catch/hour: 0
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
N O C A T C H 0 0 0
__________ ________
0
ItafDeme SURVEY:2120301 STATION 20
DATE :16/03/2012 GEAR TYPE: BT NO: 1POSITIONlat N 5ー24
start stop duration Lon W 0ー12
TIME :11:10:00 11:40:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 40 40 Validity : 0
Towing dir: 0ー Wire out : 150 Speed : 3.1 kn
Sorted : 15 Total catch: 15.2 Catch/hour: 30.52
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Octopus vulgaris 6 4 19.66
26
Pagruscaeruleostictus 5.6 136 18.35
Epinephelusaeneus 5.4 6 17.69
Balistespunctatus 3.6 8 11.8
Fistulariatabacaria 1.5 58 4.91
Lagocephaluslaevigatus 1.4 8 4.59
Balistescapriscus 0.9 2 2.95
Pseudupeneusprayensis 0.8 28 2.62
Pagellusbellottii 0.7 4 2.29
Sepia officinalishierredda 0.6 30 1.97
Dentexcanariensis 0.6 6 1.97
Citharichthysstampflii 0.6 12 1.97
Grammoplitesgruveli 0.5 4 1.64
Aluteruspunctata 0.5 2 1.64
Decapterusmacarellus 0.4 28 1.31 19
Loligo vulgaris 0.4 86 1.31
Chloroscombruschrysurus 0.3 2 0.98
Arnoglossusimperialis 0.3 20 0.98
Priacanthusarenatus 0.3 6 0.98
Bothuspodasafricanus 0.1 2 0.33
Selene dorsalis 0.02 2 0.07
_________ ________
Total 30.52 100
ItafDeme SURVEY:2120301 STATION 21
DATE :16/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 5ー39
start stop duration Lon E 0ー17
TIME :20:15:00 20:45:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 43 40 Validity : 0
Towing dir: 0ー Wire out : 50 Speed : 3.2 kn
Sorted : 0 Total catch: 0.11 Catch/hour: 0.22
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Engraulisencrasicolus 0.02 2 9.09
Sepia officinalishierredda 0.2 4 90.91
Decapterusmacarellus 0.002 2 0
__________ ________
0.22 100
ItafDeme SURVEY:2120301 STATION 22
DATE :17/03/2012 GEAR TYPE: BT NO: 1POSITIONlat N 6ー1.
start stop duration Lon E 1ー9.
TIME :11:50:00 12:20:00 30.0 (min) Purpose : 1
27
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 23 21 Validity : 0
Towing dir: 0ー Wire out : 100 Speed : 3.0 kn
Sorted : 14 Total catch: 13.7 Catch/hour: 27.5
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Diodonhystrix 6.8 14 24.73
Aluteruspunctata 5 14 18.18
Ephippionguttifer 3.8 4 13.82
Rhinobatosrhinobatos 3.8 4 13.82
Balistescapriscus 2.6 6 9.45
Sepia officinalishierredda 1.8 6 6.55
Lagocephaluslaevigatus 1.4 2 5.09
Zanobatusshoenleinii 0.7 2 2.55
Xyrichtysnovacula 0.6 10 2.18
Pagruscaeruleostictus 0.6 2 2.18
Dentexcanariensis 0.4 2 1.45
__________ ________
Total 27.5 100
ItafDeme SURVEY:2120301 STATION 23
DATE :17/03/2012 GEAR TYPE: PT NO: 2POSITIONlat N 5ー54
start stop duration Lon E 1ー9.
TIME :14:05:00 14:35:00 30.0 (min) Purpose : 1
LOG : 0.00 0.00 0.0 Region 2800
FDEPTH: 0 0 Gear cond : 0
BDEPTH: 41 42 Validity : 0
Towing dir: 0ー Wire out : 150 Speed : 3.2 kn
Sorted : 17 Total catch: 17.0 Catch/hour: 34.02
SPECIES CATCH/HOUR% OF TOTC SAMP
weight Numbers
Alectisalexandrinus 21.6 44 63.49 20
Brachydeuterusauritus 9 34 26.46 24
Selene dorsalis 1.42 16 4.17 21
Decapteruspunctatus 1.2 472 3.53 22
Decapterusmacarellus 0.8 140 2.35 23
__________ ________
Total 34.02 100
ANNEXE III Scientific Equipment and Gear
28
Scientific Equipment
Simrad Sounder ER 60 Simrad Integrator BI60 1 Transducer38 kHz ES38B 1 Transducer 120 kHz ES120-7 PlanometerTAMAYA One Japanese CTD brand ALEC A Current meter Anderaa 1 Mid water trawl (Norwegian type) 2 Demersal trawls 1 FURUNO net recorder 3 Reversing thermometers 3 Mechanical weighing scales(10,50 et 100 kg) An Electronic precision balance range 10 kg 5 Fisher meters 2 Calipers Keys determination (Blache, Cadenat et Stauch, 1970 - Bellemans, Sagna et Scilabba,
1988) Instruments for animal biology.
Description of fishing gear
The main gear is a pelagic trawl society Akraham*(Norway) whose dimensions are detailed
below.
The secondary device is a standard trawl fish 31.82m long, 33.9m with the length of the
beadto24.5 m headline, 45 mm stretched mesh size at the pocket.
The company is the manufacturer Akraham approved research vessel Fridtjof Nansen (Norway).
29
PELAGICTRAWLUSED
Annex IV Number and Biomass of main Species
30
species CLUSL02 ENGEN01 PODBR01 CARDE04 CARDE04 CARDE04
Sardinellamaderensis
Engraulisencrasicolus
Brachydeuterusauritus
Decapterusmacarellus
Decapterusmacarellus
Decapterusmacarellus
sample 13 14 15 16 17 17
Totnumber
63 60 78 7 47 9
weight 0.3 0.2 1.7 0.5 0.05 0.37
length
2 13 8
3 34 1
4
5
6 2 6 1
7 31 29
8 29 25 2
9 1 23
10 22
11 7
12 2
13 4 2
14 3 1
15 6 1
16 2 1
17 5 1
18 1 1
19
20
21
31
species CARDE04 CARDE04 CARAL01 CARDE01 CARDE04 CARSL01 PODBR01
Decapterusmacarellus
Decapterusmacarellus
Alectisalexandrinus
Decapteruspunctatus
Decapterusmacarellus
Selenedorsalis
Brachydeuteru
auritus
Totnumber
16 14 22 59 35 8 17
weight 0.01 0.2 10.8 0.15 0.2 0.71 4.5
Length(cm)
2 2
3 6 1
4 8 3 5 2
5 3 8 8 3
6 6 13 4
7 5 23 17
8 10 1
9
10
11
12 6
13 5
14 5
15 1
16
17 1
18 1 1
19 1 1
20 1
21
22 2
23 1
24 1
25
26
27
28
29 1
30
31
32 1
33
34 2
35 5
36 2
37
38
39
40 1
41
42
4143
44 1
45 2
32
46
47 1
33
Annex V Length Frequencies of Main Pelagic Species
Length freq. dist. – Decapterus macarellus Length freq. dist.- Sardinella maderensis
Length freq. dist.- Engraulis encrasicolus Length freq. dist. – Brachydeuterus auritus
34
Length freq. distribution - Alectisalexandrines Length freq. distribution - Selene dorsalis
35
Annex VI Families/ genera in the catch analysis
Group Taxon SpeciesSardinellaaurita S. auritaSardinellamaderensis S. maderensisChinchards Trachurussp. T. trecae
D. rhonchus, D. macarellus, D.punctatus
Anchois Engraulis encrasicolusAutres pélagiques 1 Clupeiformes1 Ilishaafricana
Engraulis encrasicolusAutres pélagiques 2 Carangidae2 Sélène dorsalis
ChloroscombruschrysurusAlectisalexandrinus
Scombridae EuthynnusalletteratusSardasardaScomberjaponicus
Sphyraenidae Sphyraenaguachancho
AutresTrichiuruslepturusZeus faber
Demersaux Sparidae3 DentexangolensisD. macrophthalmusD. congoensisD. canariensisD. barnardiPagellusbellottiiSparuscaeruleostictusS. pagrus africanus
autres taxii PseudupeneusprayensisBig-eyegrunt Brachydeuterusauritus
Ariomma bondiPomadasysincisusGaleoidesdecadactylus
Mesopelagiques Myctophidae3Autres mesopelagiques
Plancton Calanoidae Calanussp.Euphausiidae Meganyctiphanessp.Autre plancton
36
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