5. Results of fishing experiments.

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 of fish on the shelf. The results may thus not be directly comparable to catch rates from previous fishing surveys. The data from the prepositioned trawl hauls will later be used for estimates of biomass of groups of demersal species.

The bottom trawl used is a shrimp-cum-fish trawl (see Annex 1) and it may not be as efficient for shrimp as specially designed shrimp-trawls.

Oriente.

The fish on the shelf between Bocas del Dragon and Cabo Codera can roughly be identified as two assemblages: that belonging to the inner part of the shelf, inside the Testigos Archipelago and the Margarita Island and on the coastal side of the Cariaco Trench in which pelagic fish, sardines and anchovies dominate and catfish and croakers are the most common groups of the demersals; and on the other hand the assemblage found over the outer parts of the shelf outside the Testigos and Margarita Island and westwards past the Tortuga Island where the pelagic fish is represented nearly only by carangids and the demersal fish is dominated by snappers and grunts with some breams, groupers and glasseyes. This grouping is used in the following description of the composition and catch rates of the fishing experiments. The complete record of all hauls made are shown in Annex II, Stations 122 to 180 and the position of the stations can be seen in Figure 1.

Table 1 shows an analysis of catch rates (standardized to kg per hours towing) for all successfull bottom trawl hauls by broad groups of fish and for the inner and outer shelf separately. Catch rates of trawl for pelagic fish such as sardines are not very meaningful, but there is an impression of high availability of this group on the inner shelf. Squid are present in nearly all catches, but with highest rates on the outer shelf. The two species Loligo paelei and L. plei are of about equal abundance.

Table 2 shows the catch rates by families for the demersal fish on the inner and outer shelf parts. Catfish, croakers and hairtails dominate the inner part and snappers with some breams , groupers and glasseyes the outer part. Bagre marinus was the most common catfish and Micropogonias furnieri a common croaker. Among the snappers, the small sized Pristipomoides macropthalmus dominated with some large Lutjanus analis and L. bucanella. The sparids were mostly represented by Calamus sp. and the groupers by Mycteroperca sp. The glasseyes were nearly only Priacanthus areanatus.

Table 1. ORIENTE. Catch rates for main groups in trawl stations standardized to kg/hour.

INNER SHELF

STA. NO.	Demersal	Pelagic	Squid	Sharks	Other
122	1406.40	527.20	1.00		69.60
123	39.12	37.44	2.64		72.12
124	365.60	260.40		2.60	266.40
129		5780.00
130	278.20	122.70	1.80		31.30
131	27.60	712.80	12.00		12.44
132	3.12	8.14		0.15	54.21
133	36.40	373.10	2.80	32.00	58.90
134	459.40	887.24	2.38	1.94	26.20
135	1103.40	112.00	8.40	0.80	70.20
136	83.60	85.80	19.80		5.00
150	1109.16				89.72
151	4.88	137.40	63.52		50.96
152	86.30	3.00	14.60	2,40	17.80
153		231.40			16.20
154	38.40	112.00			22.20
155		144.00			0.30.
156	11.20		3.20		0.40
165	3.20	7.40	1.40		1.94
166	18.00	161.80	80.00		35.40
167	67.30	62.94	4.66		39.88
168	339.60		23.60		135.80
169	2.88	100.42			67.44
170		8.20	11.80		43.10
171		51.40	3.20	12.00	42.80
172	75.20	7.20	26.40	9.60	18.60
173	25.20	10.20	1.20	7.20	152.00
174	30.60	46.40	8.00	0.50	59.38
MEAN	200.53	356.01	10.44	2.47	52.15

OUTER SHELF

STA. NO.	Demersal	Pelagic	Squid	Sharks	Other
125	252.60	437.40	15.40	6.80	18.40
126	72.20			22.20	1427.60
127	216.50	0.50	3.00	13.00	19.60
128		56.62		2.20	307.40
138	13.00	4.40	74.40		132.20
140	224.20	32.50	23.90	6.20	8.10
141	1.40	12.20	17.80	1.20	6.60
142	56.50	164.00	27.00		70.50
143	103.00	153.00	13.10		3.90
144	17.20	112.80	16.40	12.40	55.60
147	40.80	145.20	17.20	1.00	33.00
148	103.00	16.40	192.00		18.60
149	257.40	1.50	132.00		108.00
157	90.60	16.20	13.80		221.40
158	123.24	16.00	1.00		3.32
159	10.60	13.40	1.32	3.90	10.04
160	61.90	198.00	0.26		12.70
161	188.46	0.12	3.60		234.88
162				8.00	5.60
163	611.20				318.40
176	25.40	0.40	6.80	4.00	10.80
177	156.64	0.14	3.20		0.44
178			2.10
179	22.10	0.10	64.00		5.90
MEAN	110.33	57.54	26.18	3.37	126.37

Table 2. ORIENTE. Catch rates by families for demersal fish, kg/hour.

INNER SHELF

STA. NO.	Catfish	Croakers	Grunts	Groupers	Hairtails	Other
122		3.00		3.40	1400.00	597.80
123		8.64	14.88	12.72	2.88	112.20
124	309.40	34.20	6.40		15.60	529.40
129						5780.00
130	131.40	124.20	8.20		14.40	155.80
131		14.40			13.20	737.24
132	0.55	1.10	1.47			62.50
133	1.40	16.80	11.20		7.00	466.80
134	244.00	58.36	147.84	1.20	8.00	917.76
135	806.40	4.60	290.00	2.40		191.40
136			80.40		3.20	110.60
137						1929,20
150	1024.40	84.76				89.72
151			2.80	2.00		251.88
152	43.60	16.20		26.40	0.10	37.80
153						247.60
154		2.40	32.40	3.60		134.20
155						144.30
156			11.20			3.60.
165	3.20					10.74
166	2.00		16.00			277.20
167		1.44			65.86	107.48
168					339.60	159.40
169			2.88			167.86
170						63,10
171						109.40
172					75.20	61.80
173	1.40	12.60		3.60	7.60	170.60
174		20.00	1.50	1.60	7.50	114.28
MEAN	88.54	13.89	21.63	1.97	67.59	473.05

OUTER SHELF

STA. NO.	Snappers	Grunts	Breams	Groupers	Glasseyes	Other
125	3.40	238.20		1.20	9.80	478.00
126	11.40	60.80				1449.80
127	44.00	145.50			27.00	36.10
128						366.22
138	8.40			0.60	4.00	211.00
140	195.50		1.40	11.80	15.50	70.70
141	0.10			1.30		37.80
142		55.50		1.00		261.50
143	11.30	71.00		1.70	19.00	170.00
144	5.80	1.10		0.70	9.60	197.20
147	25.60	3.20			12.00	196.40
148	14.00	75.00		0.60	13.40	227.00
149	182.40	75.00				241.50
157	77.40				13.20	251.40
158	50.00			72.44	0.80	20.32
159	9.20			1.10	0.30	28.66
160	50.50		10.80		0.60	210.96
161	1.86	4.90	117.20	60.00	4.50	238.60
162						13.60
163	37.00	57.20	207.00	150.20	159.80	318.40
176	20.80		4.60			22.00
177	121.24	31.60	3.20		0.60	3.78
178						2.10
179	13.10	3.80	5.20			70.00
MEAN	36.79	34.28	14.56	12.61	12.09	213.46

Table 3. ORIENTE. Catch rates by families of pelagic fish in pelagic and bottom trawl hauls, kg/hour,

INNER SHELF

STA. NO.	Anchovies	Sardines	Carangids	Scombrids	Barracudas	Other
122		127.20	400.00	2.00		1475.00
123			37.44			113.88
124	143.40	111.80	5.20		223.60	411.00
129		5780.00
130	4.50	117.00	1.20			311.30
131		674.40	38.40		0.24	51.80
132		2.35	5.79	29.67	14.80	13.01
133	4.20	368.90		1.40	54.60	74.10
134		005.00	2.24		5.00	484.92
135		33.60	70.40	18.20	16.80	1147.80
136		79.80	6.00		1.40	107.00
137	486.00	1360.00	3.20			72.00
150						1198.88
151			137.40	23.80	1.60	93.96
152		0.40	2.60			121.10
153	43.60	187.80		1.80	4.00	10.40
154		82.00	30.00		1.20	59.40
155	90.00	54.00		0.10		0.20
156					0.40	14.40
165	1.40	3.00	3.00	0.60		5.94
166	102.00	16.00	43.80	10.00		123.40
167	0.50	39.60	22.84		15.20	96.64
168				17.40	3.20'	478.40
169	57.60	39.94	2.88		54.72	15.60
170			8.20		4.60	50.30
171		0.20	51.20		1.40	56.60
172			7.20		1.60	128.20
173	2.40	5.60	2.20		0.40	185.20
174	7.20	28.00	11.20		0.40	98.08
MEAN	32.51	344.99	31.05	3.62	13.97	241.33

OUTER SHELF

STA. NO.	Sardines	Carangids	Scombrids	Barracudas	Other
125	407.00	30.40			293.20
126					1522.00
127		0.50			252.10
128	52.00	1.02	3.60	45.00	264.60
138		4.40			219.60
139					256.30
140		32.50			262.40
141	1.00	11.20		1.20	25.80
142	145.00	19.00			154.00
143		153.00			120.00
144	3.80	108.80	0.20		101.60
145					41.10
146		3.00			239.39
147	2.40	142.00	0.80		92.00
148		16.40			313.60
149	1.50				497.40
157		15.90	0.30		325.80
158		16.00			127.56
159		13.40			25.86
160		193.50	4.50		74.86
161		0.12			426.94
162					13.60
163					929.60
164					103.30
175					131.10
176		0.40			47.00
177	0.04	0.10			160.28
178					2.10
179		0.10			92.00
MEAN .-	21.13	26.27	0.32	1.59	245.35

Table 3 shows the catch rates for the different types of pelagic fish in the trawl stations from the inner and outer shelf. Engraulis eurystole was a common anchovy and in addition to sardinella, the scaled herring Harengula jaguana was caught on some stations. Of the carangids Trachurus lathami was by far the most common with large sized fish occurring widely at depths beyond abt 40 m.

Pooled samples of the length compositions of the most common of these species are shown in Annex III.

Six trawl hauls were made on the slope from 200 - 400 m. Catch rates of shrimp were insignificant except at stations 139 and 146 with abt. 50 and 30 kg/hour of Paeneopsis serrata. At the first of these abt. 6 kg/hour of Metanephrops binghami was also obtained.

Western part, from Cabo Codera to Peninsula de Guajira.

The bottom trawl hauls between Cabo Cadera and Cabo San Roman are summarized in Table 4, where the catches have been grouped by two bottom depth zones, i.e. more or less than 60 m, and by main categories of fish. It is seen that in the shallow waters the catch is dominated by small pelagic fish. The demersal group, which comprises the most commercially important fish species, is caught in up to abt. 180 Kg/hour, at average 44 Kg/hour. Beyond 60 m bottom depth the average catch of demersal fish is practically the same, but maximum catch is 285 Kg/hour. The average catch of squid is 14 Kg/hour in the deeper waters, with 118 Kg/hour as the maximum. Longer series of data are needed to make more firm conclusions. Dominating commercial demersal species are: In the 0-60 m bottom depth zone: snappers (Lutjanus analis and L. synagris mainly); 60-100 m: barracudas (Sphyraena picudilla), snappers (L. analis, L. synagris, Pristipomoides macropthalmus, Rhombopolites aurorubens), hairtails (Trichiurus lepturus), bigeyes (Priacanthus arenatus) and squid (Loligo); 100-200 m: hairtails, goatfish (Upeneus parvus), bigeyes and snapper (Pristipomoides macropthalmus)

Table 4. WESTERN COASTS. From Cabo Cadera to Peninsula de Paraguana. Catch rates for main groups in trawl stations standardized to kg/hour.

INNER SHELF, BOTTOM DEPTHS LESS THAN 60 M

ST. NO.	DEP.	Demersal	Pelagic	Squid	Sharks	Shrimps	Other
182	55	52.1	2528.6	22.2	28.8		37.0
196	49	41.9	19.6	8.8			19.3
201	10		2.0				288.0
205	35	34.7	132.4			0.5	92.1
206			281.0	0.6			11.0
209	32	0.0	0.4				9.5
210	44	65.9	29.7	3.9	5.2		35.1
212	15		43.2
214	47	68.0	38.8	16.0			3.4
215	34	25.3	02.2	2.0			21.6
216	21	178.7	76.7				195.3
220	18	107.4	17.0	0.4	2.4		87.3
221	35	37.1	20.7	1.7			13.2
223	28	3.4	7.4		5.2		2.2
MEAN		43.9	234.9	3.9	2.9		58.2

OUTER SHELF, BOTTOM DEPTHS GREATER THAN 60 M

ST. NO.	DEP.	Demersal	Pelagic	Squid	Sharks	Shrimps	Other
181	66	9.0		32.2			120.7
183	95	7.2	673.4	5.6		0.4	96.8
184	71	34.4	22.8	1.2		0.9	140.9
185	274	1.6		251	12	5.4	11.0
186	169	2.1		4.0	4.2	1.2	127.0
187	98	2.4	1.0		2.1	0.2	14.1
188	189	0.8		30.4	12.6		21.8
189	328	1.2		3.0	0.9	7.2	82.3
190	267	0.6		6.1	0.4	1.9	1.8
191	263	7.4		19.4	2.2	0.2	20.1
192	239	7.2		117.6	0.9		45.7
193	321	2.7			0.9		661.6
194	167	166.0		0.8			15.4
195	64	284.9	17.0	15.0			101.8
197	71	237.6	193.5	2.9			42.3
198	146	73.2	0.9			0.2	97.3
199	228	4.8		1.2		0.6	146.0
200	258	3.1	0.6	9.4		3.9	10.20
202	184	165.3			1.5		0.7
203	69	25.2	151.8	57.0	9.4		4.2
204	63	4.6	102.1	27.2			15.3
207	61	50.0	3.2			2.0	72.0
208	64	49.4	1.2	1.2			63.2
213	73	80.0		5.4			22.0
217	258			6.6		4.1	55.6
218	338	0.8		3.0		5.3	12.0
219	318			0.0	46.4	3.2	10.4
222	196	33.9		17.2		0.0	1.4
224	74		98.6	18.0			84.4
225	77	35.3	0.2	7.4			2.2
MEAN		43.0	42.2	13.9	2.7	1.2	70.0

Table 5. GULF OF VENEZUELA. Catch rates for main groups in trawl stations standardized to kg/hour.

INNER GULF

ST. NO.	DEP.	Demersal	Pelagic	Squid	Sharks	Shrimps	Other
230		66.0	200.0	7.6			7.6
231	29	104.6 42	13.9	1.2			28.4
232	36	9.2	4.6	4.8		0.8	19.6
233	25	34.6	3.2	11.2			32.9
234	31	87.8	41.7	3.0			63.3
235	10		1549.2				2.8
236	11		00	0.1			2.0
237	13	30.6	76.0		4.2		10.9
230	14	11.0	17.0
239	9	7.7	17.6				1.0
240	11	79.4 43	99.6				40.7
241	15	7.0 1	352	0.2	12.4		1.2
242	12	120.5 88	220.5			17.0	62.0
243	11	7.6 2	58.5.		1.8	1.6	25.8
244	15	583.5 530	305.3		6.3	98.7	111.0
245	21	24.0 17	1046.2			0.1	15.8
246	12	7.6	179.	4.3
247	17	54.4	36.3	3.2			1.0
248	20		23.5
249	24		18.0
250	20	47.3	43.4	3.2		0.6	21.8
MEAN		61.1	1822	1.8	1.1	5.6	21.3

OUTER GULF AND OFFSHORE.

ST. NO.	DEP.	Demersal	Pelagic	Squid	Sharks	Shrimps	Other
223	28	3.4	7.4		5.2		2.2
224	74		174.2	18.0			8.8
225	77	35.3	0.2	7.4			2.2
226	77	21.2	9.0			3.4	151.7
227	58	30.6	28.3	5.1		1.8	153.7
228	20		367.5				1.0
229	8		16.2	0.3
252	46	7.3	834.4	24.4			4.0
253	51	14.8	34.1	29.2			51.2
254	53	7.3	11.9	52.0		0.4	31.5
255	59	3.0	2.6.	66.0		0.1	18.8
256	47	35.1	14.4	3.6		2:8	140.2
257	15		85.2	0.2			0.4
258	58	12.4	20.3	9.6		1.8	285.1
259	53	113.6	20.2	27.0			128.2
260	S3	14.1	42.0	6.4		5.4	61.0
261	12	42.4	20.9	0.3		27.6	4.7
262	11	48.2	19.6			35.9	20.8
263	49	4.6	111.1	2.4		1.0	20.8
264	44	22.0	45.0	135.2			72.2
265	34	93.8	109.0		2.0		9.8
266	66	58.5	9.2	16.0		1.6	60.4
267	73	17.3	9.8	14.4		1.2	99.1
268	70	0.2	16.3	8.6	3.2	0.7	101.7
MEAN		24.4	83.7	17.7	0.4	3.4	59.9

In the Gulf of Venezuela the catch data have been divided by an inner and outer part, with a north/south dividing line from Punto Fijo and westwards, Table 5. In the inner area the average catch of commercial demersal species is abt. 60 Kg/hour and shrimp abt 6 Kg/hour. Maximum catch of shrimp was 98 Kg/hour at st. 244 in the inner gulf. The species was the Atlantic Seabob (Xiphopenaeus kroyeri), small sized, abt. 3 grams individual weight. In the outer part the average catch of demersal was abt. 25 Kg/hour, and squid 18 Kg/hour. The maximum catch rate of squid was 135 Kg/hour of Loligo paelei at station 264. In the waters of less depth than 60 m the dominating commercial species in the catch was croakers (Micropogonias furnieri, Cynoscion acoupa). In the deeper waters barracuda (Sphyraena picudilla), bigeyes (Priacanthus arenatus) and snappers (Lutjanus analis, L. synagris, Rhomboplites aurorubens) dominated together with squid (Loligo plei, L. paelei) . In this preliminary first analysis day and night hauls are mixed. Especially for shrimp who often show diurnal behaviour this will give biased results. A more thorough analysis will be made later when more data becomes available.

Figure 1. Course tracks, fishing stations and hydrographic profiles. Oriente coast.

Figure 2. Course tracks, fishing stations and hydrographic profiles. Western coasts.

Figure 3. Temperature at sea surface. Oriente coast.

Figure 4. Temperature at sea surface. Western coasts.

Figure 5a. Hydrographic profiles. Oriente coast. PUNTA CARIBE 15-16.2 1988

Figure 5b. Hydrographic profiles. Oriente coast. PUERTO LA CRUZ 20-21.2 1968

Figure 6a. Hydrographic profiles. Western coasts. CABO SAN ROMAN 28.2 1988

Figure 6b. Hydrographic profiles. Western coasts. GULF OF VENEZUELA 28.2-2.3 1988

Figure 7. Distribution of pelagic fish from acoustic system. Oriente coast.

Figure 8. Distribution of pelagic fish from the acoustic system. Western coasts.