Some of the results of the fishing experiments are commented on below. One should note, however, that most of the fishing forms part of a programme for "swept area" biomass estimation, and for this purpose the trawl stations are positioned in advance more or less randomly and with no intention of obtaining high catch rates. The catch rates thus do not simulate those of a commercial fishery and they are presented here merely to give a rough impression of the general occurrence, composition and abundance offish on the shelf.
All catches were sampled for composition in weight and numbers by species and size sampling was made of important species, using total length also for shrimp.
GABON
Various assemblages of demersal fish may be described on the Gabon shelf, but here we will only distinguish between samples from the inner shelf: 0 - 55 m, and the outer shelf: 60 - 150 m. In addition comes a small number of stations from the slope: 200 - 600 m.
The location of the trawl stations are shown in Figure 1 and records of the catches are presented in Annex IV, station nos. 1 - 55. Table 1 shows an analysis of catch rates (standardized to kg per hours towing) for all successful bottom trawl hauls by broad groups offish and for the inner shelf, outer shelf and deep slope separately. "Demersal" comprises the families Sciaenidae, Ariidae, Pomadasiydae, Serranidae, Sparidae and Lutjanidae and "Pelagic": Engraulidae, Clupeidae, Carangidae, Scombridae, Sphyraenidae and Trichiuridae. Mean catch rates are highest for the demersal fish and this group will be analysed further below.
Pelagic fish.
Catch rates for pelagic fish by bottom trawls are not very meaningful except as an indicator of the species present. The highest rates are from hauls at about 100m depth on the outer shelf and consisted of horse mackerel with some Spanish mackerel, Scomber japonicus. The highest rates of pelagics on the inner shelf consisted of barracudas and Ilisha sardine. The size distribution of samples of barracudas is shown in ANNEX II.
Cephalopods.
The Cephalopod catches on the inner shelf consisted mainly of cuttlefish (84%) dominated by Sepia officinalis. On the outer shelf catch rates were lower, but still dominated by cuttlefish with some squid and a little octopus. In the deep slope hauls the Cephalopod catches consisted mainly of shortfin squid Illex coindetii. Sampled size distribution of cuttlefish is shown in ANNEX II.
Shrimp.
The most common shrimp on the inner shelf was the Guinea shrimp Parapenaeopsis atlantica, while large sized specimens of pink shrimp Penaeus notialis and caramote prawn Penaeus kerathurus represented one third of the shrimp catches. The last two species mainly appeared at night time. Striped red shrimp Aristeus varidens was the main component of the small catches of shrimp in the deep slope hauls with some deep water rose shrimp Parapenaeus longirostris. For size distributions of shrimp see ANNEX II.
Table 1. GABON Catch rates for main groups in trawl stations standardized to kg/hour.
INNER SHELF
|
ST. NO. |
DEP. |
Demersal |
Pelagic |
Cephalop. |
Shrimp |
Lobster |
Other |
|
1 |
40 |
45.0 |
|
6.0 |
|
|
24.7 |
|
5 |
55 |
136.2 |
1.4 |
41.5 |
0.6 |
|
50.4 |
|
6 |
13 |
24.9 |
11.7 |
5.6 |
2.7 |
28.0 |
49.1 |
|
7 |
13 |
7.9 |
6.7 |
3.4 |
|
8.0 |
25.2 |
|
8 |
12 |
|
45.0 |
4.4 |
|
|
34.5 |
|
9 |
45 |
2.6 |
|
28.0 |
|
|
7.8 |
|
13 |
30 |
96.4 |
2.3 |
20.0 |
4.2 |
|
49.6 |
|
14 |
12 |
163.1 |
28.0 |
|
14.5 |
|
149.5 |
|
15 |
33 |
15.6 |
|
56.0 |
3.4 |
|
62.9 |
|
16 |
43 |
34.0 |
0.1 |
15.0 |
0.1 |
|
13.2 |
|
17 |
23 |
79.5 |
2.6 |
|
|
|
153.5 |
|
18 |
14 |
149.0 |
17.4 |
0.8 |
|
7.0 |
123.8 |
|
19 |
37 |
2.0 |
4.1 |
3.1 |
|
|
7.9 |
|
20 |
23 |
3.4 |
3.0 |
3.2 |
|
|
12.4 |
|
21 |
11 |
62.8 |
35.2 |
1.4 |
|
4.0 |
58.5 |
|
22 |
10 |
18.4 |
14.4 |
|
|
1.7 |
66.2 |
|
23 |
10 |
90.0 |
194.4 |
4.2 |
1.2 |
0.7 |
106.2 |
|
24 |
10 |
30.8 |
70.0 |
1.0 |
6.4 |
0.3 |
35.1 |
|
25 |
25 |
150.6 |
0.6 |
15.2 |
2.7 |
|
62.3 |
|
26 |
36 |
10.8 |
0.2 |
23.2 |
7.6 |
|
92.1 |
|
29 |
42 |
18.0 |
|
21.2 |
0.1 |
|
25.6 |
|
30 |
26 |
52.5 |
|
8.5 |
|
|
99.5 |
|
31 |
31 |
25.7 |
|
7.2 |
2.6 |
|
77.3 |
|
35 |
46 |
2630.6 |
|
40.0 |
|
|
232.0 |
|
36 |
39 |
369.4 |
90.8 |
8.0 |
|
|
48.0 |
|
37 |
45 |
1328.0 |
2.0 |
5.6 |
|
|
105.3 |
|
38 |
39 |
60.4 |
|
6.0 |
0.2 |
|
59.4 |
|
41 |
37 |
11.0 |
0.2 |
4.7 |
|
|
8.6 |
|
42 |
28 |
11.4 |
3.5 |
|
0.0 |
|
8.0 |
|
43 |
36 |
12.2 |
0.1 |
5.7 |
0.1 |
|
4.2 |
|
48 |
53 |
91.0 |
|
15.8 |
|
|
23.8 |
|
49 |
28 |
226.4 |
4.6 |
1.0 |
|
|
17.8 |
|
50 |
16 |
178.6 |
27.5 |
|
|
|
165.6 |
|
51 |
16 |
115.3 |
121.5 |
13.3 |
0.3 |
13.3 |
185.8 |
|
52 |
12 |
114.8 |
144.7 |
|
|
1.6 |
35.2 |
|
53 |
25 |
86.8 |
14.0 |
|
4.2 |
|
42.9 |
|
MEAN |
|
179.3 |
23.5 |
10.2 |
1.4 |
1.8 |
64.5 |
|
ST. NO. |
DEP. |
Demersal |
Pelagic |
Cephalop. |
Shrimp |
Lobster |
Other |
|
2 |
107 |
424.7 |
396.1 |
5.1 |
|
|
169.0 |
|
3 |
114 |
272.2 |
2.2 |
2.9 |
|
|
175.4 |
|
4 |
73 |
353.4 |
82.4 |
6.4 |
|
|
77.8 |
|
10 |
108 |
311.4 |
96.0 |
1.6 |
|
|
111.0 |
|
11 |
112 |
1128.8 |
1232.0 |
5.2 |
|
|
102.2 |
|
12 |
67 |
15.0 |
|
10.8 |
|
|
78.6 |
|
27 |
109 |
123.6 |
2.2 |
4.9 |
0.8 |
|
26.8 |
|
28 |
77 |
31.1 |
0.0 |
11.3 |
|
|
19.7 |
|
32 |
107 |
70.3 |
|
1.2 |
|
|
6.3 |
|
33 |
105 |
87.5 |
1.0 |
1.5 |
|
|
10.5 |
|
34 |
75 |
199.8 |
0.3 |
3.6 |
|
|
18.7 |
|
40 |
78 |
174.1 |
6.0 |
11.5 |
|
|
19.8 |
|
44 |
67 |
154.0 |
36.0 |
16.8 |
0.2 |
|
86.4 |
|
MEAN |
|
257.3 |
142.6 |
6.3 |
0.0 |
|
69.4 |
|
ST. NO. |
DEP. |
Demersal |
Pelagic |
Cephalop. |
Shrimp |
Lobster |
Other |
|
39 |
207 |
6.0 |
|
26.4 |
|
|
148.7 |
|
45 |
402 |
|
|
22.5 |
0.5 |
2.7 |
237.9 |
|
46 |
598 |
|
|
2.4 |
6.0 |
13.6 |
287.0 |
|
47 |
248 |
6.3 |
|
35.2 |
2.8 |
5.1 |
239.9 |
|
54 |
635 |
|
|
12.5 |
6.9 |
8.0 |
126.3 |
|
55 |
529 |
|
|
10.5 |
1.8 |
7.5 |
48.1 |
|
MEAN |
|
2.0 |
|
18.2 |
3.0 |
6.1 |
181.3 |
The catches of lobster from the inner shelf were nearly all the royal spiny lobster Panulirus regius with small amounts of red locust lobster Scyllarides herklotsii.
Demersal fish.
Table 2 shows the catch rates by families of the demersal fish for the inner and outer shelf. Some of the hauls on the inner shelf gave large catches of good sized commercial types of fish. Especially noteworthy are the stations 35, 36 and 37 from the area about 20 nm W/NW of Pte. Panga.
The Sparids represent the most common form of demersal fish in the catches, both on the inner - and outer shelf. On the inner shelf the Sparid catches were dominated by the blue spotted sea bream Sparus caerolostictus and the Canary dentex Dentex canariensis both of good size, see ANNEX II. The main species offshore were the smaller sized species: Dentex congoensis and Boops boops while the red pandora Pagellus bellotti appeared both on the inner and outer parts.
The medium sized (cfr. ANNEX II) golden African snapper Lutjanus fulgens represented 85% of the snapper catches with very large sized brown snapper L. dentatus contributing 10%.
A large catch of good sized rubberlip grunt Plectorhynchus mediterraneus (cfr. ANNEX II) contributed about 60% of the catch of this group with the small sized bigeye grunt Brachydeuterus auritus another 27% and various Pomadasys species the rest.
The croakers which together with the catfish were found nearly only at depths of less than 20 m. were dominated by the species Cassava croaker Pseudotolithus senegalensis of medium size (cfr. ANNEX II) with some longneck croaker P. typus. The main catfish species were the smoothmouth Arius heudeloti and the rough head sea catfish A. latiscutatis.
The catches of groupers consisted mainly of large sized specimens of white grouper Epinephelus aenus both on the inner and outer shelf.
CONGO
The compositions of the assemblages of fish on the Congo shelf are different from those in Gabon. This could be related to the types of substratum. Bottom samples showed a predominance of soft mud - clay off Congo while those from Gabon consisted mostly of silt and sand. Also here the catch data are analysed for the inner shelf (to 55 m), the outer shelf (56 - 120 m) and the slope (200 - 700 m) separately.
The location of the trawl stations are shown in Figure 1 and records of the catches are presented in Annex IV, station nos. 56 through 96. Table 3 shows an analysis of catch rates (standardized to kg per hours towing) for all successful bottom trawl hauls by broad groups of fish and for the inner shelf, outer shelf and deep slope separately. "Demersal" comprises the families Sciaenidae, Ariidae, Pomadasyidae, Serranidae, Sparidae and "Pelagic": Clupeidae, Carangidae, Scombridae, Sphyraenidae and Trichiuridae.
Table 2. GABON Catch rates by families for demersal fish, kg/hr.
INNER SHELF
|
ST. NO. |
DEP. |
Sparids |
Snappers |
Grunts |
Groupers |
Croak + catf |
Other |
|
1 |
40 |
45.0 |
|
|
|
|
30.7 |
|
5 |
55 |
79.2 |
|
56.8 |
0.1 |
|
94.0 |
|
6 |
13 |
20.0 |
0.9 |
3.0 |
|
1.0 |
97.1 |
|
7 |
13 |
1.5 |
|
5.0 |
|
1.4 |
43.3 |
|
8 |
12 |
|
|
|
|
|
83.9 |
|
9 |
45 |
2.6 |
|
|
|
|
35.8 |
|
13 |
30 |
95.0 |
|
|
1.4 |
|
76.1 |
|
14 |
12 |
4.5 |
5.0 |
135.6 |
|
18.0 |
192.0 |
|
15 |
33 |
15.6 |
|
|
|
|
122.4 |
|
16 |
43 |
33.0 |
|
|
|
1.0 |
28.4 |
|
17 |
23 |
66.1 |
13.0 |
|
0.4 |
|
156.1 |
|
18 |
14 |
45.0 |
60.7 |
15.3 |
|
28.0 |
149.1 |
|
19 |
37 |
2.0 |
|
|
|
|
15.1 |
|
20 |
23 |
3.4 |
|
0.0 |
|
|
18.6 |
|
21 |
11 |
|
|
21.0 |
|
41.8 |
99.1 |
|
22 |
10 |
5.1 |
|
8.2 |
|
5.1 |
82.4 |
|
23 |
10 |
|
3.0 |
31.2 |
|
55.8 |
306.7 |
|
24 |
10 |
|
|
0.8 |
|
30.0 |
112.8 |
|
25 |
25 |
124.4 |
|
22.2 |
|
4.0 |
80.8 |
|
26 |
36 |
8.0 |
|
2.0 |
|
|
123.2 |
|
29 |
42 |
18.0 |
|
|
|
|
46.9 |
|
30 |
26 |
16.0 |
36.2 |
0.2 |
|
|
108.1 |
|
31 |
31 |
23.2 |
|
1.3 |
1.2 |
|
87.1 |
|
35 |
46 |
563.6 |
920.0 |
1020.0 |
127.0 |
|
272.0 |
|
36 |
39 |
212.4 |
146.0 |
5.0 |
6.0 |
|
146.8 |
|
37 |
45 |
664.8 |
411.0 |
51.0 |
108.2 |
93.0 |
112.9 |
|
38 |
39 |
38.9 |
17.0 |
4.5 |
|
|
65.6 |
|
41 |
37 |
10.0 |
|
1.0 |
|
|
13.6 |
|
42 |
28 |
|
|
10.2 |
1.2 |
|
11.6 |
|
43 |
36 |
6.6 |
|
0.0 |
5.5 |
|
10.3 |
|
48 |
53 |
86.8 |
|
2.8 |
1.3 |
|
39.6 |
|
49 |
28 |
140.0 |
52.0 |
|
32.0 |
2.4 |
23.4 |
|
50 |
16 |
|
|
157.6 |
|
21.0 |
193.1 |
|
51 |
16 |
|
|
25.3 |
|
90.0 |
334.3 |
|
52 |
12 |
|
|
108.0 |
|
6.8 |
181.5 |
|
53 |
25 |
|
|
82.4 |
|
4.4 |
61.2 |
|
MEAN |
|
64.7 |
46.2 |
49.2 |
7.9 |
11.2 |
101.5 |
|
ST. NO. |
DEP. |
Sparids |
Snappers |
Grunts |
Groupers |
Croak + catf |
Other |
|
2 |
107 |
410.7 |
|
|
14.0 |
|
570.2 |
|
3 |
114 |
270.7 |
|
|
1.5 |
|
180.7 |
|
4 |
73 |
346.6 |
|
6.4 |
|
0.4 |
166.6 |
|
10 |
108 |
311.4 |
|
|
|
|
208.6 |
|
11 |
112 |
1108.8 |
|
|
20.0 |
|
1339.4 |
|
12 |
67 |
15.0 |
|
|
|
|
89.4 |
|
27 |
109 |
82.0 |
|
8.0 |
32.0 |
1.6 |
34.7 |
|
28 |
77 |
30.0 |
|
1.0 |
0.1 |
|
31.0 |
|
32 |
107 |
70.0 |
|
|
0.3 |
|
7.5 |
|
33 |
105 |
73.3 |
|
|
14.2 |
|
13.0 |
|
34 |
75 |
189.0 |
|
|
10.8 |
|
22.6 |
|
39 |
207 |
6.0 |
|
|
|
|
175.1 |
|
44 |
67 |
150.5 |
|
3.0 |
0.5 |
|
139.4 |
|
MEAN |
|
235.7 |
|
1.4 |
7.1 |
0.1 |
229.1 |
Cephalopods were virtually absent from the catches on the inner shelf. On the outer shelf the group was represented mainly by the common cuttlefish Sepia officinalis, while the slope catches were mainly shortfin squid Illex coindetii. The size composition of samples of this species is shown in ANNEX II.
Shrimp.
About 2/3 of the shrimp catches on the inner shelf consisted of the relatively small sized Guinea shrimp Parapenaeopsis atlantica and about 1/4 large size pink shrimp Penaeus notialis, see ANNEX II for size distributions. The highest catch rates of pink shrimp were obtained in hauls during the day in contrast to the experience from Gabon. This change in the behaviour of the shrimp may be related to the turbidity of the water and the type of substratum.
Shrimp catches were low on the outer shelf except a catch of mainly pink shrimp at 57 m of depth on station 87.
The high catch rates of shrimp in the slope are mainly due to large catches of spider shrimp Nematocarcinus africanus, a small sized species of uncertain commercial value (cfr. size sample in ANNEX II). Deep water rose shrimp Parapenaeus longirostris was found between 200 and 400 m with catch rates up to 10 kg/hour (for size see ANNEX II), and the striped red shrimp Aristeus varidens and the blue and red shrimp Aristeus antennatus were caught at 400 - 500 m with rates up to 20 kg/hour, but mean catch rates were 4-5 kg/hour. As seen from ANNEX II these species were rather small sized.
Lobster.
Small numbers of royal spiny lobster Panulirus regius appeared in nearly all the inshore hauls.
Sharks.
Sharks were caught in some amounts in some of the hauls in shallow water and on the slope off the shelf. On the inner shelf the most common species were the barled hound-shark Leptocharias smithii and spinner shark Carcharinus brevipinna. In the slope hauls the little gulper shark Centrophorus uyato represented more than 70% of the catch with rates up to 250 kg/hour.
Table 3. CONGO Catch rates for main groups in trawl stations standardized to kg/hour.
INNER SHELF
|
ST. NO. |
DEP. |
Demersal |
Pelagic |
Sharks |
Shrimp |
Lobster |
Other |
|
58 |
22 |
214.6 |
126.0 |
6.0 |
12.0 |
0.4 |
80.2 |
|
59 |
14 |
222.2 |
43.7 |
15.4 |
30.0 |
2.0 |
115.8 |
|
60 |
14 |
180.1 |
100.2 |
122.4 |
8.0 |
6.0 |
99.4 |
|
61 |
25 |
152.6 |
82.6 |
1.0 |
1.7 |
6.0 |
44.4 |
|
62 |
15 |
139.2 |
103.2 |
25.0 |
21.6 |
|
74.6 |
|
63 |
26 |
223.6 |
12.8 |
5.0 |
9.1 |
6.0 |
172.2 |
|
64 |
15 |
187.2 |
11.0 |
54.6 |
9.6 |
3.8 |
91.6 |
|
71 |
16 |
117.0 |
327.8 |
6.3 |
6.1 |
3.0 |
21.3 |
|
72 |
34 |
87.6 |
130.4 |
|
0.9 |
2.4 |
210.6 |
|
73 |
30 |
74.1 |
43.5 |
15.0 |
8.2 |
4.2 |
84.3 |
|
74 |
30 |
79.9 |
16.8 |
6.3 |
17.6 |
3.7 |
68.6 |
|
75 |
41 |
270.6 |
1.8 |
3.5 |
26.1 |
0.2 |
72.2 |
|
79 |
25 |
70.3 |
151.2 |
|
3.5 |
15.0 |
101.5 |
|
80 |
14 |
59.2 |
105.7 |
19.0 |
2.8 |
|
36.0 |
|
81 |
12 |
53.9 |
138.7 |
12.4 |
24.5 |
|
59.5 |
|
88 |
41 |
356.0 |
22.6 |
|
5.0 |
4.7 |
137.4 |
|
89 |
18 |
65.7 |
26.3 |
|
0.6 |
|
14.2 |
|
90 |
47 |
183.6 |
13.5 |
|
2.3 |
|
71.8 |
|
MEAN |
|
152.0 |
81.0 |
16.2 |
10.5 |
3.1 |
86.4 |
|
ST. NO. |
DEP. |
Demersal |
Pelagic |
Sharks |
Cephalopod |
Shrimp |
Other |
|
56 |
102 |
57.8 |
19.8 |
|
14.4 |
3.2 |
97.7 |
|
57 |
65 |
408.3 |
25.4 |
|
8.5 |
0.5 |
73.3 |
|
68 |
98 |
85.5 |
122.2 |
0.8 |
14.5 |
0.1 |
160.5 |
|
69 |
60 |
674.4 |
147.5 |
14.0 |
1.5 |
2.0 |
5.2 |
|
78 |
61 |
471.6 |
33.9 |
|
32.0 |
0.4 |
16.6 |
|
86 |
92 |
60.8 |
62.8 |
|
11.0 |
0.8 |
88.2 |
|
87 |
57 |
681.9 |
78.0 |
17.4 |
29.9 |
16.4 |
18.4 |
|
91 |
93 |
48.0 |
15.0 |
|
0.3 |
1.5 |
71.2 |
|
MEAN |
|
311.0 |
63.0 |
4.0 |
14.0 |
3.1 |
66.4 |
|
ST. NO. |
DEP. |
Demersal |
Pelagic |
Sharks |
Cephalopod |
Shrimp |
Other |
|
65 |
202 |
12.0 |
0.4 |
307.2 |
28.0 |
1.2 |
86.0 |
|
66 |
299 |
|
4.2 |
104.5 |
18.0 |
18.4 |
74.7 |
|
67 |
395 |
|
21.0 |
24.8 |
1.4 |
140.5 |
140.0 |
|
76 |
321 |
|
42.0 |
70.8 |
14.0 |
185.7 |
157.2 |
|
77 |
506 |
|
0.8 |
1.3 |
6.0 |
6.6 |
95.5 |
|
83 |
697 |
|
|
|
|
2.0 |
75.0 |
|
84 |
400 |
|
3.5 |
27.0 |
30.0 |
68.0 |
129.7 |
|
85 |
200 |
36.2 |
5.6 |
53.4 |
8.2 |
7.4 |
153.3 |
|
92 |
453 |
|
0.7 |
1.6 |
10.0 |
5.0 |
126.0 |
|
93 |
348 |
|
30.6 |
|
10.2 |
188.0 |
240.8 |
|
94 |
251 |
|
18.0 |
158.5 |
6.6 |
1.4 |
21.1 |
|
95 |
203 |
267.3 |
21.1 |
35.0 |
33.0 |
9.5 |
108.7 |
|
96 |
251 |
|
5.0 |
14.0 |
33.5 |
9.1 |
93.5 |
|
MEAN |
|
24.2 |
11.7 |
61.4 |
15.3 |
49.5 |
115.5 |
Catch rates of pelagic fish in bottom trawling is not very meaningful, but may give some indications of the forms present, see Table 4. West African ilisha was the only clupeid caught apart from the sporadic appearance of small numbers of sardinella. The bumper Chloroscombrus chrysurus was the main representative of the Carangids. The guachanche barracuda Sphyraena guachancho occurred mostly about 60 m of depth with rates up to 50 kg/hour, see ANNEX II for size distributions. Some rather small sized horse mackerel Trachurus trecae appeared in some of the offshore catches.
Demersal fish.
Table 5 shows catch rates for demersal fish. The croakers, the commercially most important group, gives the highest mean catch in the inner shelf hauls. Half the total catch was the cassava croaker Pseudotolithus senegalensis with the longneck croaker P. typus contributing another 20%. The rest was the smaller sized boe drum Pteroscion peli (cfr. ANNEX II for samples of size distributions). The croaker catches on the outer shelf were dominated by the smaller sized blackmouth croaker Pentheroscion mbizi. Some of the slope hauls at 200 - 300 m had catches up to about 60 kg/hour of species of meagre Argyrosomus, with some specimens of very large size.
Table 4. CONGO Catch rates by families for pelagic fish, kg/hr.
INNER SHELF
|
ST. NO. |
DEP. |
Clupeids |
Carangids |
Barracudas |
Scombrids |
Trichiurid |
Other |
|
58 |
22 |
48.0 |
50.4 |
9.6 |
|
18.0 |
313.2 |
|
59 |
14 |
16.0 |
10.7 |
14.0 |
|
3.0 |
385.4 |
|
60 |
14 |
42.0 |
30.6 |
17.6 |
|
10.0 |
415.9 |
|
61 |
25 |
32.0 |
24.0 |
25.0 |
|
1.6 |
205.7 |
|
62 |
15 |
44.2 |
12.0 |
37.5 |
2.0 |
7.5 |
260.4 |
|
63 |
26 |
2.4 |
6.4 |
|
|
4.0 |
415.9 |
|
64 |
15 |
3.0 |
6.2 |
1.8 |
|
|
346.8 |
|
70 |
28 |
|
|
|
|
|
|
|
71 |
16 |
56.4 |
214.2 |
42.0 |
4.0 |
11.2 |
153.7 |
|
72 |
34 |
24.8 |
81.6 |
8.0 |
|
16.0 |
301.6 |
|
73 |
30 |
18.0 |
15.3 |
|
|
10.2 |
185.9 |
|
74 |
30 |
3.0 |
12.9 |
|
|
0.9 |
176.1 |
|
75 |
41 |
1.2 |
|
|
|
0.6 |
372.6 |
|
79 |
25 |
52.5 |
70.3 |
7.3 |
|
21.0 |
190.3 |
|
80 |
14 |
27.1 |
25.8 |
48.0 |
|
4.8 |
117.0 |
|
81 |
12 |
36.4 |
44.8 |
47.0 |
|
10.5 |
150.3 |
|
88 |
41 |
0.5 |
2.5 |
|
|
19.6 |
503.1 |
|
89 |
18 |
1.9 |
18.7 |
5.2 |
|
0.5 |
80.5 |
|
90 |
47 |
2.0 |
7.5 |
4.0 |
|
|
257.7 |
|
MEAN |
|
21.6 |
33.3 |
14.0 |
0.3 |
7.3 |
254.3 |
|
ST. NO. |
DEP. |
Clupeids |
Carangids |
Barracudas |
Hairtails |
Other |
|
56 |
102 |
1.5 |
12.0 |
5.1 |
1.2 |
173.1 |
|
57 |
65 |
|
14.0 |
8.0 |
3.4 |
490.6 |
|
68 |
98 |
0.2 |
120.0 |
|
|
263.4 |
|
69 |
60 |
|
66.0 |
49.5 |
30.0 |
699.1 |
|
78 |
61 |
|
4.3 |
11.2 |
2.4 |
536.8 |
|
86 |
92 |
3.6. |
58.0 |
|
1.2 |
160.8 |
|
87 |
57 |
|
26.0 |
31.2 |
20.8 |
764.1 |
|
91 |
93 |
|
4.8 |
|
10.2 |
121.0 |
|
MEAN |
|
0.6 |
38.1 |
13.1 |
8.6 |
401.1 |
In contrast to the Gabon fauna Sparids were not abundant in the catches in Congo, catches on the outer shelf mainly contained red pandora Pagellus bellotti with some Angola dentex Dentex angolensis.
In inshore waters butterfish Stromateus fiatola appeared in some hauls usually in moderate amounts, but with one rate of 180 kg/hour. A size sample is shown in ANNEX II.
A few of the hauls in about 200 m depth gave catches of bearded brotula Brotula barbata of about 30 kg/hour of good sized specimens (cfr. ANNEX II).
Table 5. CONGO Catch rates by families for demersal fish, kg/hr.
INNER SHELF
|
ST. NO. |
DEP. |
Grunts |
Croakers |
Catfish |
Sparids |
Groupers |
Other |
|
58 |
22 |
138.8 |
72.4 |
3.4 |
|
|
224.6 |
|
59 |
14 |
4.6 |
205.2 |
12.4 |
|
|
206.9 |
|
60 |
14 |
17.9 |
153.0 |
9.2 |
|
|
336.0 |
|
61 |
25 |
91.6 |
61.0 |
|
|
|
135.7 |
|
62 |
15 |
42.0 |
95.2 |
2.0 |
|
|
224.4 |
|
63 |
26 |
75.2 |
114.4 |
15.2 |
|
18.8 |
205.1 |
|
64 |
15 |
102.0 |
81.6 |
3.6 |
|
|
170.7 |
|
71 |
16 |
57.2 |
55.6 |
4.2 |
|
|
364.5 |
|
72 |
34 |
48.0 |
36.0 |
3.6 |
|
|
344.4 |
|
73 |
30 |
33.3 |
36.9 |
3.8 |
|
0.1 |
155.2 |
|
74 |
30 |
33.0 |
42.3 |
4.6 |
|
|
113.0 |
|
75 |
41 |
204.0 |
66.6 |
|
|
|
103.8 |
|
79 |
25 |
7.3 |
63.0 |
|
|
|
271.2 |
|
80 |
14 |
11.6 |
23.2 |
24.4 |
|
|
163.5 |
|
81 |
12 |
7.0 |
31.5 |
15.4 |
|
|
235.1 |
|
88 |
41 |
252.0 |
104.0 |
|
|
|
169.7 |
|
89 |
18 |
64.0 |
0.1 |
1.5 |
|
|
41.2 |
|
90 |
47 |
90.0 |
86.1 |
|
7.5 |
|
87.6 |
|
MEAN |
|
71.0 |
73.7 |
5.7 |
0.4 |
1.0 |
197.4 |
|
ST. NO. |
DEP. |
Grunts |
Sparids |
Croakers |
Groupers |
Other |
|
56 |
102 |
6.0 |
40.8 |
11.0 |
|
135.1 |
|
57 |
65 |
350.0 |
45.5 |
4.0 |
8.8 |
107.7 |
|
68 |
98 |
1.0 |
20.0 |
12.5 |
52.0 |
298.1 |
|
69 |
60 |
600.0 |
45.0 |
28.4 |
1.0 |
170.2 |
|
78 |
61 |
464.0 |
5.2 |
2.4 |
|
83.0 |
|
86 |
92 |
10.4 |
28.8 |
21.6 |
|
162.8 |
|
87 |
57 |
598.0 |
44.2 |
39.0. |
0.7 |
160.1 |
|
91 |
93 |
3.0 |
12.6 |
32.4 |
|
88.0 |
|
MEAN |
|
254.0 |
30.2 |
18.9 |
7.8 |
150.6 |
Figure 2. Temperature at sea surface.
Figure 3. Hydrographic profiles (EQUATOR 27-28.1 1989)
Figure 3. Hydrographic profiles (POINTE PANGA 1-2.2 1989)
Figure 3. Hydrographic profiles (POINTE NOIRE 6-7.2 1989)
Figure 4. Distribution of pelagic and demersal fish from acoustic system. (A)
Figure 4. Distribution of pelagic and demersal fish from acoustic system. (B)
