Collected data were analyzed using STATISTICA software (Statsoft Inc., Tulsa, 131 OK, USA). The ANOVA was used to assess the effects of country pressures on different marine species. All significance levels were fixed at p < 0.05.

1) Captures and stock progression of some marine fish species

It results from estimations analysis ( Figure 1 and Figure 2 ), that Guinea exerts more pressure on marine fish particulary on Ethmalosa fimbrita followed by Benin and Togo on Sardinella aurita with (F_{(12, 18,812)} = 14.856, p = 0.00). It is due to the fact fish farming development is slowing down in Guinea. According to [34] and [35] , fish farming started in Guinea by years 2000 s with average 3000 fish farmers for annual production of 4106 tons. However, the need is estimated to more than 134,000 tons. High capture could be justified by this deficit contrary to other countries where fish farming is meanly developed.

Even though data assessment regarding stock estimation is difficult with new models, some FAO data and other international organizations enabled us to have an insight on stock progression in Africa ( Figure 3 ). It results from these analyses that 66.3% of fish stocks are threatened in Africa ( Figure 3 ).

Engraulis encrasicolus, pelagic fish is the only species of its family encountrered in Togo water system [24] [38] - [41] . It constitutes only one stock in the sub-region distributed among Benin, Ivory Coast, Ghana and Togo ( Figure 4 and Table 1 ) [42] .

It is a small fish of maximum 20 centimeters length characterized by round and fusiform body ( Figure 4 ). The snout is elongated, pointed with roster above the large oblique mouth. The maxillary passes the posterior border of eye. The dorsal fin, short is situated in the mid of the body; the origin of the anal fin is behind the basis of the dorsal. The caudal fin is forked with two modified scales, symmetric in the basis of rays. Scales are easily removable. The back is blue-green to clear-grey colored. In the presence of scales, faces are silver banded with dark-grey line. Along the West-African coast, Engraulis encrasicolus presents two kinds of size: a small form generally encountered at the limits of gulf of Guinea (11˚N to l˚S) where hydrological conditions are stable, and a big form localized in the Northern and Southern zones seasonally subject to trade wind [43] .

E. encrasicolus divided by [44] in several local races with low migration rate, is distributed in the whole Eastern Atlantic, from Norway coasts to South Africa. It is also spread over the Mediterranean basin including the black sea and Azov sea and the Manche. It is significantly present on West African coasts from Ivory Coast to Benin ( Figure 5 ) [43] .

With gregarious life style, it live in coastal low depth waters till 150 m and sometimes 400 m [45] and also frequent estuaries from surface to bottom. [46] reports the presence of the species from Liberia to Benin coasts, more in surface water at night than at day time. The anchor appreciates diluted water and ponds more than salt waters ranging from 5‰ to 41‰.

In Togo water bodies, the first maturity height ranges from 5 to 7 cm [24] . [21] reported that in Ghana, the first maturity height is 5.7 cm (FL) corresponding to average 6.4 cm (TL) by considering the TL and FL relationship established by [47] . According to [25] , the L50 is 8.4 cm in male and 8.8 cm in female. In other side, it is from 12 to 13 cm (Fage, 1911); 11 to 12 cm [48] ; 11.8 cm [49] ; 11.0 cm [50] . For smallest individuals, the sexual maturity height is 8.2 cm [51] and 8.6 cm and 9.7 cm respectively for males and females [52] .

[53] reports in his research work in Mauritania that reproduction depends mainly on temperature which depends on salinity and then trophic richness of the species habitat. He also confirms results of [54] and [55] . According to [53] , the species reproduce in water with 14˚C temperature. It is sexual reproduction mode. [56] reported that a female weighing 25 g can spawn meanly 275,000 eggs per season hatching by the 2 to 4 next days after spawning [46] . According to [25] , maturation in E. encrasicolus starts in Ivorian waters from November-December to March. It grows rapidly and its life duration is 3 years.

It fed on small planktonic crustaceans, eggs and pelagic fish fries. According to [57] , natural mortality in larval stage depends on cannibalism exerted by adults. E. encrasicolus is harvested using pelagic trawl and fishing nets; but in Togo, Benin and Guinea, it is harvested using turning fishing nets in the beach ( Figure 5 ).

The zoological classification of Sardinella aurita is shown in Table 2 .

According to [58] , Sardinella aurita has elongated, round and most compressed body ( Figure 6 ). The operculum is slightly prolonged, mean eyes; the skull top is striated (7 - 14) on parietal fronts, terminal muzzle, and rounded upper jaw, a second supra-maxillary with sub-equal upper and lower borders. Thin numerous gills spines. The dorsal fin origin is near the body’s midst. The anal fin is in the basis of the dorsal. The two late rays are longer than those preceding. Pelvic fins are under dorsal and have 9 rays. The back is blue-green colored; flanks are silver with golden line and golden spot behind the operculum. There is a distinct dark spot on the posterior border of the operculum and yellow dorsal fin with black anterior rays.

Sardinella aurita in Eastern Atlantic is spread over West African coasts, Mediterranean and the black sea coasts and in Western it is found in Cape Code in Argentina. It is also found in western Pacific from Japan to Philippines. It is present in the Western part of gulf of Guinea ( Figure 7 ).

According to [59] , Sardinella aurita, along the West African coast shows two populations in term of size. A small with sexual maturity height varying from 12 to 104 cm is generally encountered in the limits of the gulf of Guinea (11˚N to l˚S) where hydrologic conditions are stable. The big form is located in North and south in zones exposed to trade wind, can be found in Mauritania, Senegal, Gabon, Congo and Angola with 19 - 20 cm maturity height. The most evident character is reduction of maximum and mean length in maturity height measurements. This character shows dwarfish in S. aurita and at least three dwarf populations were identified: Guinea-Liberia, Ivory Coast-Ghana, Gabon. But, on Ghanaian coasts we also find the big size population [59] . [46] [60] [61] estimated that S. aurita prefers deeper waters than coasts. It could frequent 70 - 100 m depth where surface waters are hot and comes to surface during upwelling. Most of S. aurita are found in the East of Cap the Three Points. Marking carried out in Ghana by [62] showed that their migration during cold season (July-September) is followed by movement toward East till Togo. They return to West from October to December but at high depth before coming to the original habitat. It could be more abundant in isobaths from 40 to 200 m. Spawning happens mainly in coastal waters during upwelling season. During low salt water period, S. aurita is not found in water with salinity lower than 35%. It also fears coasts influenced by terrestrial runoff [63] . Fries spend more time in nursery with low movements on the coast contrary to adults. S. aurita feeds mainly on plankton. It is able to retain small particles [64] . It is possible that unavailability of zooplankton could affect growth, fecundity, stock height or behavior of the species [65] . Besides, low zooplankton biomass will correspond to high predation of eggs and larvae [66] . Adults have behavior that could be influenced by zooplankton scarcity. Indeed, plankton concentrations near the coast are higher than the bottom [67] . Some research works indicate that height (FL) is 16.7 cm in male and 17.1 cm in female [68] .

Brachydeuterus auritus belongs to Haemulidae family with 11 genus and its zoological position is mentioned in Table 3 below.

According [69] , Brachydeuterus auritus is characterized alongated and compressed body with height 2.6 to 3 times standard length. It has big eyes and large protractile mouth. The snout is smallest than eyes diameter. The dorsal fin possesses 12 moderated spines and 11 to 13 soft rays. The third and sometimes the forth spine is longest than others. The anal fin has 3 spines with 9 to 10 soft rays. The caudal fin is deeply inserted. The lateral line is made of 48 to 52 scales with 4 to 5 under ranks. The back is olive colored, flanks and belly are silver colored. On the top of the operculum, there is a black spot. Some small black spots are also viewable on the basis of the dorsal fin ( Figure 8 ).

Brachydeuterus auritus is of species which biology is little assessed. Important research work carried out in Ivory Coast, Ghana, Nigeria, Togo and Congo focused mainly on the distribution of the species [37] [71] ). B. auritus is semi-pelagic species eurybenthic. It is subject to tropical and sub-tropical distribution and is found along coastal areas from Mauritania to Angola at depth 10 to 100 m [72] and in Togo on sand bottom from 0 to 100 m depth [24] [37] [39] [73] . According to [74] and [75] , B. auritus is abundant in Ghana at 55 to 90 m depth. [76] reported that the species moves in group and is located around the thermocline. Young specimens are found only in the coastal round though adults dwell in large but come progressively in the coastal area during spawning period.

The multiple feeding behaviors of B. auritus are limited to microscopic zooplankton, shrimps, fish juveniles, cephalopods, benthic crustaceans and sometimes polychetes [77] Planktonic crustaceans constitute the major part of food diet especially big copepods that are abundant near coastal areas. B. auritus fed near the bottom in day time and in intermediary water body at night. [77] reported that feeding could be important during the rainy season where zooplankton is abundant. Food diet could vary between the long rainy season and the long dry season. The short rainy season food diet is not significantly different from dry seasons. If planktonic crustaceans are less abundant (during the summer), the species changes its diet. [78] and [79] confirmed the works of [77] and revealed that the species prefers polychetes and fish. The works of [37] are the only focused on the biology of B. auritus in Togo water bodies and assessed growth and first sexual maturity height. In Congo, the first sexual maturity height is 12 cm (FL) for female [80] ; in Ivory Coast 13.8 cm and 14.5 cm (TL) [77] and then 12.25 and 11.96 cm (FL) [81] . In Ghana 14.8 for male and 15.1 cm for female [82] ; in Senegal 14.4 and 14.8 cm [72] .

Pseudotolitus elongates belongs to Sciaenidae family and constitutes the most important fish community of gulf of Guinea [83] . The Sciaenidae family counts 270 species distributed in 70 average genus according to [84] and [85] with main representatives that belong to the Pseudotolithus genus ( Table 4 ). There are eight genus distributed in sixteen species known from West African coasts. Among these species, we only retain three belonging to Pseudotolithus genus often found in brackish water [86] . They are mainly Pseudotolithus elongatus, Pseudotolithus senegalensis and Pseudotolithus typus.

Pseudotolithus elongatus is a fusiform fish, alongated and laterally compressed with long dorsal fin deeply inserted according to [69] . It has 11 dorsal spines and between 29 and 35 dorsal soft rays with short head and large oblique snout. Its identification is difficult due to allometry. It has villiform teeth arranged in shrink bands in both jaws. In addition, P. elongatus has average 19 to 2 branchiospines on the first gill arch. Scales are ctenoid on the body and cycloid on the chest and head. It is gray silver colored with reddish aspect. The dorsal and caudal fins are gray and the back is olive colored ( Figure 9 ).

Distribution area of P. elongatus in Eastern Atlantic mainly spread from Southern Senegal till Angola ( Figure 10 ). The species is considerate as native of the gulf of Guinea ranging from Southern Bissau Guinea till Congo where it appears highly. Highest captures come from Guinean coasts [15] [87] . However, according to [88] P. elongtaus is scarces in Ivory Coast where water conditions (upwelling) don’t fit this species ecology.

P. elongatus dwells in the moody bottom of coastal water bodies. According to [87] and [89] , it can also be found in coastal lagoons and estuaries that represent spawning media. During rainy season, it spawns in large water (average 100 m). P. elongatus fed on shrimps, fish juveniles and other crustaceans. Both of oocytes don’t reach maturity at same time in P. elongatus. It is characterized by continuous gametogenesis and spawn along the year [87] [89] [90] .

Ethmalosa fimbrita spends its first year in brackish water where it spawns and migrates to sea water in the second year [91] ( Table 5 ).

Its height is average 35 cm standard length, but it is most commonly comprised between 20 and 25 cm. in Ghanaian water bodies, this species reaches its sexual maturity at 22 cm [92] . The same study reported fecundity ranging from 16000 for 21.2 cm fish weighing 88 g to 51750 cm for 30.4 cm specimen weighing 242.7 g. The sex ratio (male/female) was 0.88. Fisheries data from delta Niger revealed mean annual mortality rate estimated to 1.2 per year [93] . According to [69] , E. frimbrita doesn’t have dorsal spine but soft dorsal rays comprised between 16 and 19 and anal soft rays between 19 and 25 ( Figure 11 ). The compressed body has scales on the belly due to vertebra comprised between 40 and 44. Long inferior branchiospines, thin and numerous and three times longer than gill filaments. It also possess superior branchiospines highly curved in form of V. By the same way, E. frimbrita has a black spot behind operculum followed by other spots. The dorsal fin is black and the caudal is yellow.

Ethmalosa fimbrita is present in coastal area, estuaries and often in Dakhla River of occidental Sahara till Lobito in Angola corresponding to Northern limits and extreme South of 25˚C isotherms the year round. According to [16] , few small specimens are present in Lake Nokoué in Benin. The same author reported that remarks made by [94] in Cap-Vert regarding location are not verified.

Ethmalosa fimbrita is euryhaline and brackish migrator ( Figure 12 ). It lives in low depth coastal water, lagoons and estuaries and often in fresh water at more than 300 km offstream (Gambie River). The most abundant populations are found in lagoons and estuaries [96] . Generally, 12 cm specimens of E. fimbrita prefer more than 5 ppt salinity. E. fimbrita practices spring migration to coastal area for spawning (reproduction in sea water, lagoons and estuaries with salinity comprised between 3.5 and 38 ppt) followed by autumn migration to the large. The species lives average 4 to 5 years and the first spawning happens at 1 year age [97] . It mainly fed on phytoplankton.