6. Results of the bottom trawl sampling

The results of the individual hauls are given in Appendix 3 and length frequency distribution for some of the important demersal species are shown in Appendix 4. The catch rates are standardized to kg per hours trawling. The catches are aggregated in broad groups of fish. “Pelagic” comprises Clupeidae (sardine), Engraulidae (anchovies), Carangidae, Scombridae, Sphyraenidae (barracuda) and Trichiuridae (hairtails). “Demersal” includes the families Sciaenidae (croakers), Lutjanidae (snappers), Pomadasidae (grunts), Serranidae (groupers), Ariidae (catfish) and Priacanthidae (glasseyes). This grouping is used in the following description of the composition and catch rates in the bottom trawl fishing.

Oriente.

The area on the shelf between Bocas de Dragon and Cabo Cadera is grouped as in previous reports: the inner part of the shelf, inside the Testigos Archipelago and the Margarita Island and on the coastal side of the Cariaco Trench; the outer part outside the Testigos and the Margarita Island and westward past the Tortuga Island.

Table 1 shows the catch rates for outer and inner parts respectively. The catches of all groups are lower than in Survey 2 but comparable to the result of Survey 1 with the exception of squid which is the lowest recorded. In the inner part catfish and croakers dominated and in the outer part snappers and grunts were the most important demersal species as shown in Table 2. The highest catch rate of croakers 940 kg/h was obtained in haul 765. High catch rates of snappers, more than 100 kg/h were recorded in several hauls north of Margarita Island towards Tortuga Island. The catches of shrimp were generally low in the inner part. In the outer part catches of about 20 kg/h were made at 400-500 m (Pleoticus robustus) and at 800 m mostly noncommersial species.

The catch rates of pelagic species taken in bottom trawl Table 3 are very much dependant of the vertical distribution of the different species. Carangids and scombrids appear to be overrepresented in the bottom trawl catches compared to composition in the pelagic hauls. The result indicates higher abundance of sardines in the outer part which is in disagreement with the acoustic result. The catches of pelagic species in the bottom trawl should be regarded as by-catches not reflecting abundance.

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

INNER

ST. NO.	DEP.	Pelagic	Demersal	Shark	Squids	Shrimp	Other
737	66	97.70	11.20	7.00	5.80	1.40	45.52
738	41	32.40	63.60		0.40	1.80	5,40
749	40	2.00	35.60		4.40		25.70
750	43	335.50	180.50				46.00
752	32	450.00	468.00	54.00			14.40
753	37	39.80	19.60		5.60		11.90
754	51	77.50	18.60	14.50	0.40		1.40
761	39	21.80	4.70		1.00		0.40
762	33	81.30	17.90	1.60	0.50		11.20
763	73	32.50	34.16	13.50	1.00		67.62
764	81	39.00	44.00		3.40		24.56
765	127	1540.00	985.10	25.00	17.50	1.40	8.44
769	59	169.00	111.20		2.40		64.20
770	48	2.80	10.40		20.80		201.10
MEAN		208.66	143.18	8.26	4.51	0.33	37.70

OUTER

ST. NO.	DEP.	Pelagic	Demersal	Shark	Squids	Shrimp	Other
736	94	6.90	45.20		2.80		20.70
742	438	1.44		25.32	1.92	10.44	26.16
743	843			1.80	7.74	20.88	61.98
744	43	0.40	119.04	1.20	2.40		10.64
745	40	4.60			15.40		0.60
746	42	10.40	213.60		10.50		1.20
771	70	2.24	157.78		3.98		73.74
772	70	987.60	565.60		5.00	14.00	15.60
776	162	2.10	34.20		1.00		15.90
777	206		35.58				32.02
778	26	18.50	11.50				194.74
779	62	1.00					28.60
780	306			1.50	18.00	5.25	830.55
783	37	12.20	26.00		4.20		10.10
784	65	118.80	184.10		8.40	0.20	25.40
785	73	4.00	162.90				52.60
786	45	1.50	250.60		1.60		73.00
787	56	561.30	114.60			0.20	2.20
788	97	22.40	533.40				162.40
789	137		33.80		2.60		5.20
790	411	0.05		3.05	23.00	19.30	76.30
791	100	1.60	22.80	10.60	0.40	0.40	42.80
792	128	153.30	139.50	1.50		1.74	32.22
794	73	8.30	212.00				48.60
795	78	5.00	54.40		0.40	0.40	51.80
796	532			4.90	19.50	21.50	52.90
797	68	315.00	98.88	8.00	1.40		23.00
798	27		239.80				707.74
799	83	954.00	207.20				22.40
800	660	2.50		11.00	9.00	8.75	118.25
801	69	93.40	243.30	8.60		0.40	75.80
802	117
803	70	2.00	126.20		5.20	0.80	68.60
MEAN		99.74	116.12	2.35	4.38	3.16	89.82

Western part from Cabo Codera to Peninsula de Guajira.

The results of bottom hauls between Cabo Codera and Cabo San Roman are summarized in Table 4. The mean catch of demersal species is 53 kg/h or less than half of the catch rates in Oriente and lower than in Survey 2 but comparable to catch rates in Survey 1. The family composition of pelagic and demersal species are shown in Tables 5 and 6 respectively. The demersal catches are dominated by snappers. Mean catches of shrimp and squids were less than 4 kg/h respectively.

Table 2. ORIENTE. Catch rates by families for demersal fish in bottom trawl, kg/hour. INNER

ST. NO.	DEP.	Croakers	Catfish	Grunts	Groupers	Glasseyes	Other
737	66				1.40	2.60	164.62
738	41	60.00	3.20		0.10		40.00
749	40			15.30	1.00	7.30	44.10
750	43			21.00	1.50	6.00	533.50
732	32		468.00				518.40
753	37			18.80			58.10
754	51	1.00	14.80	1.60	1.20		93.80
761	39				2.40	2.30	23.20
762	33		2.40	11.20	0.30	3.20	95.40
763	73			13.66	0.17	2.33	132.67
764	81			1.50		0.80	108.60
765	127	940.00		7.50	3.60	14.00	1612.34
769	59	5.60		56.80	2.20	5.20	277.00
770	48				6.00		229.10
MEAN		71.90	34.89	10.53	1.44	3.12	280.77

OUTER

ST. NO.	DEP.	Croakers	Snapper	Grunts	Groupers	Glasseyes	Other
736	94		45.20				30.40
742	438						65.28
743	843						92.40
744	43		46.80	42.20	0.04	30.00	14.64
745	40						20.60
746	42		71.20	142.20	0.20		22.10
771	70		145.24	4.60	5.00	2.74	79.96
772	70		152.80	412.80			1022.20
776	162		14.80		16.80	2.60	19.00
777	206		0.48		35.10		32.02
778	26				0.50	11.00	213.24
779	62						29.60
780	306						855.30
783	37		0.70	23.40	0.30	1.60	26.50
784	65		181.20		0.40	2.50	152.80
785	73		130.40	8.10		19.40	61.60
786	45		46.60	191.00	3.80	5.00	80.30
787	56		62.00	46.20	0.60	5.80	563.70
788	97	1.40	504.00			28.00	184.80
789	137		29.80		4.00		7.80
790	411						121.70
791	100		22.80				55.80
792	128	8.10	107.40	1.50	10.20	1.50	199.56
794	73		106.50	93.50		12.00	56.90
793	78		0.40	52.60		1.40	57.60
796	532						98.80
797	68		27.28	39.20	24.00		355.80
798	27		23.40	20.00	27.40		876.74
799	83		162.40	44.80			977.20
800	660						149.50
801	69		32.90	205.00	0.90	4.50	178.20
802	117
803	70	0.80	11.60	81.20	8.00	22.80	78.60
MEAN		0.31	58.36	42.63	4.16	4.57	205.47

In the Gulf of Venezuela the area have been devided in an inner and an outer part by a line from Punto Fijo and westward. The catches by selected groups are shown in Table 7. The mean catch of demersal is 21 kg/h in the inner part compared to 52 kg/h and 61 kg/h in previous surveys. In the outer part the average catch is 58 kg/h which is higher than in Survey 1 and 2. Catches of squids and shrimps are low. Catches by family groups are shown in Tables 8 and 9. Croakers dominated in the inner part and snappers in the outer part.

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

INNER

ST. NO.	DEP.	Sardines	Hairtails	Carangids	Scombrids	Barracuda	Other
737	66	4.40	63.40	25.40	2.50	2.00	70.92
738	41	1.80	2.00	28.00		0.60	71.20
749	40	0.30				1.70	65.70
750	43	202.00	38.00	64.00	31.50		226.50
752	32	432.00				18.00	536.40
753	37	3.20		21.50	9.00	6.10	37.10
754	51	20.80	0.50	55.80		0.40	34.90
761	39		5.70	5.90		10.20	6.10
762	33	0.20	59.40	13.80		2.50	36.60
763	73	0.83		21.00		10.67	116.33
764	81			28.60		10.40	71.90
765	127			1540.00			1037.44
769	59			169.00			177.80
770	48	0.40				2.40	232.30
MEAN		47.57	12.07	140.93	3.07	4.64	194.37

OUTER

ST. NO.	DEP.	Sardines	Hairtails	Carangids	Scombrids	Barracuda	Other
736	94			0.80	6.10		68.70
742	438		1.44				63.84
743	843						92.40
744	43			0.40			133.28
745	40			4.60			16.00
746	42			7.80	1.60	1.00	225.30
771	70	1.50		0.74			235.50
772	70	980.00		7.60			600.20
776	162			2.10			51.10
777	206						67.60
77S	26			5.00		13.50	206.24
779	62			1.00			28.60
780	306						855.30
783	37	2.40	1.00	8.70	0.10		40.30
784	65	50.40		48.00	5.40	15.00	218.10
783	73			4.00			215.50
786	45					1.50	325.20
787	56	492.00		64.90	4.40		117.00
788	97			22.40			695.80
789	137						41.60
790	411		0.05				121.65
791	100				1.60		77.00
792	128	5.10		127.20	21.00		174.96
794	73			7.50	0.80		260.60
795	78	2.80		2.00	0.20		107.00
796	532						98.80
797	68	294.70		16.80	3.50		131.28
798	27						947.54
799	83	781.20		33.60	140.00		229.60
800	660		2.50				147.00
801	69	3.60		89.40	0.40		328.10
802	117
803	70			1.40	0.60		201.00
MEAN		79.20	0.15	13.82	5.63	0.91	215.82

Table 4. VENEZUELA, WESTERN PART. Catch rates for main groups in bottom trawl stations standardized to kg/hour.

ST. NO.	DEP.	Pelagic	Demersal	Shark	Squids	Shrimp	Other
804	52		83.56				13.92
805	86	9.70	21.30				15.30
806	92	55.00	90.50	12.00	5.00		71.40
807	68		112.60				23.20
808	220	14.00	71.02	2.30	2.45	8.05	70.13
809	304		1.50		3.90	2.30	74.55
810	459	1.50		0.10	5.10	8.25	15.40
811	587	3.30		0.90	3.90	10.20	69.45
812	336		250.40	3.00			643.55
813	99	46.80	112.30				20.80
814	72	5.40	76.50	3.00	3.00	4.20	86.20
815	73	4.30	94.40		1.00	2.70	58.40
816	42	10.35	65.26				51.98
817	72	30.00	52.90	7.00		1.80	21.00
818	72	14.40	37.20		6.00		15.60
819	96
820	78
821	83		12.60			0.15
822	401	0.15		1.50	40.80	8.10	58.05
823	344			1.70	1.20	1.85	43.06
824	156	13.00	21.94		3.60		8.80
825	52	16.80	95.76				53.76
826	276	29.40	6.45	8.70			34.80
827	25	2.20	43.00		1.80		3.20
828	53	7.00	99.00		5.80		28.40
829	47		37.60				14.80
MEAN		10.13	53.30	1.21	3.55	1.83	57.53

Table 5. VENEZUELA, WESTERN PART. Catch rates by families for pelagic fish in bottom trawl hauls, kg/hour.

ST. NO.	DEP.	Sardines	Hairtails	Carangids	Scombrids	Barracuda	Other
804	52						97.48
60S	86			9.70			36.60
806	92			53.00	2.00		178.90
807	68						135.80
808	220			14.00			153.95
909	304						82.25
810	459		1.50				28.85
811	587		3.30				84.45
812	336						896.95
813	99			46.80			133.10
814	72		4.80	0.60			172.90
8t5	73		2.50	0.80		1.00	156.50
816	42			5.70		4.65	117.24
817	72			13.80	7.00	9.20	82.70
818	72	0.80		4.40	2.00	7.20	56.80
819	96
820	78
821	83						12.75
822	401		0.15				108.45
823	344						47.81
824	156		4.40	8.60			34.34
825	52			3.60	13.20		149.52
826	276		29.40				49.95
827	25				2.20		48.00
828	53			2.50	4.50		133.20
829	47						52.40
MEAN		0.03	1.77	6.29	1.19	0.85	117.42

Table 6. VENEZUELA. WESTERN PART. Catch rates by families for demersal fish in bottom trawl, kg/hour.

ST. NO.	DEP.	Croakers	Snappers	Grunts	Groupers	Glasseyes	Other
804	52		71.00	0.60	0.60	0.96	24.32
805	86		3.90			9.00	33.40
606	92		87.50				146.40
807	68		53.00	56.80	0.40	0.40	25.20
808	220		64.92		6.10		96.93
809	304				1.50		80.75
810	459						30.35
811	587						87.75
812	336	198.00			32.40		646.55
813	99		80.60		31.70		67.60
814	72		52.80	15.00	0.90		109.60
815	73		51.40	23.60	2.80		83.00
816	42		41.26	7.50	3.75	2.25	72.83
817	72		51.40		0.60	0.90	59.80
818	72		29.40			0.40	43.40
819	96
820	78
821	83		5.10				7.65
822	401						108.60
823	344						47.81
824	156		17.24	1.30	3.10	0.30	25.40
825	52		79.92		0.48	0.24	85.68
826	276		4.50		1.95		72.90
827	25		21.00				29.20
828	53		89.60			6.00	44.60
829	47		37.60				14.80
MEAN		7.62	32.39	4.03	4.09	0.79	73.64

Table 7. GULF OF VENEZUELA. Catch rates for main groups in bottom trawl stations standardized to kg/hour.

INNER PART

ST. NO.	DEP.	Pelagic	Demersal	Shark	Squids	Shrimp	Other
847	21	172.56	21.24	1.08	12.00		1.92
848	16	57.60	10.00	0.80	11.20		3.60
849	23	64.42	16.80		4.32		0.60
850	20	167.00	21.50		4.50		33.50
851	13	740.90	49.30		1.60		56.30
852	15
853	24	204.00			19.50
854	42	147.70	46.90		3.20	2.20	47.00
856	35	81.30	23.60		0.40		11.00
MEAN		181.72	21.04	0.21	6.30	0.24	17.10

OUTER PART

ST. NO.	DEP.	Pelagic	Demersal	Shark	Squids	Shrimp	Other
830	46	3.30	153.60			0.50	106.20
831	74	20.18	20.00			5.68	31.84
833	73	29.76	17.68		2.16	5.60	31.08
834	67	21.40	59.00		4.80	3.20	54.90
835	76	0.40	6.30		0.40		34.40
836	67	190.20	254.28		1.80		47.25
837	61	99.60	93.80	141.40			110.80
839	67	54.10	18.50		10.30	0.10	14.50
840	58	41.40	74.00		5.10		66.00
842	50	28.60	29.70		1.20	10.00	105.18
843	69	29.30	29.58		14.80	2.20	162.76
845	57	4.90	5.80		2.40	4.20	29.30
846	46	1022.40	20.00			3.20	17.20
858	47	20.76	26.80			10.80	82.36
860	27	180.50	9.20			0.40	9.50
861	41	292.20	72.90		19.20		3.90
862	48	36.00	35.50		6.00		12.00
863	30	19.80	69.70				37.60
864	52	66.80	91.70		2.00		25.70
865	68	8.10	13.20		5.20		14.40
866	63	9.80	126.30	1.60	0.60		29.60
MEAN		103.79	58.45	6.81	3.62	2.18	48.88

Table 8. GULF OF VENEZUELA. Catch rates by families for pelagic fish in bottom trawl, kg/hour.

INNER PART

ST. NO.	DEP.	Sardines	Scombrids	Carangids	Barracuda	HairtaiIs	Other
847	21	8.88	7.44	103.44	5.52	27.60	55.92
848	16	13.60	0.80	35.20		5.00	28.60
849	23	40.76	5.40	2.30		10.20	27.48
850	20	5.50	22.00	129.50	10.00		59.50
831	13	245.40	18.50	101.80	4.40	178.20	299.80
852	15
853	24	76.20	6.00	35.40	31.80		74.10
854	42	4.80	0.80	132.40	9.70		99.30
856	35	46.40		6.10	9.30		54.50
MEAN		49.06	6.77	60.68	7.86	24.56	77.69

OUTER PART

ST. NO.	DEP.	Sardines	Scombrids	Carangids	Barracuda	Hairtails	Other
830	46	0.30		3.00			260.30
831	74	0.78		3.50	15.00	0.90	57.52
833	73	22.00	1.08	2.88	3.20	0.60	56.52
834	67	12.80		3.00		0.60	121.90
835	76			0.40			41.10
836	67	99.00	22.05	65.55	3.60		303.33
837	61	0.30	21.00	57.30	21.00		346.00
839	67	1.20	44.40	4.90	3.60		43.40
840	58	1.20	0.80	12.90	26.70		145.10
842	50	2.10		8.10	18.40		146.08
843	69	14.80		3.70	10.80		209.34
845	57	2.40		0.90	1.60		41.70
846	46	105.60	16.80	138.80	374.00		427.60
858	47	6.00		13.88			120.84
860	27	125.00	4.00	16.50	5.00	30.00	19.10
861	41	102.60	8.10	80.40	19.20	14.70	163.20
862	48	1.00	8.20	15.80	5.20	0.80	58.50
863	30	1.60	5.40	10.40	2.40		107.30
864	52	52.00	7.00	0.40	7.40		119.40
865	68		0.10	8.00			32.80
MEAN		27.53	6.94	22.77	25.86	2.38	141.05

Table 9. GULF OF VENEZUELA. Catch rates by families for demersal fish in bottom trawl, kg/hour.

INNER PART

ST. NO.	DEP.	Croakers	Snappers	Grunts	Groupers	Peprilus	Other
847	21	10.80	10.44			1.44	186.12
848	16	6.00	4.00			0.40	72.80
849	23	13.40	3.40				69.34
850	20	15.30	6.20			1.00	204.00
851	13	42.60	3.00			11.60	790.90
852	15
853	24						223.50
854	42	23.50	13.70	3.70	6.00	1.70	198.40
856	35	14.90	1.70	2.00			97.70
MEAN		14.06	4.72	0.63	0.67	1.79	204.75

OUTER PART

ST. NO.	DEP.	Croakers	Snappers	Grunts	Groupers	Glasseyes	Other
830	46		79.20	9.30		20.10	155.00
831	74	0.78	10.52		6.90	1.80	57.70
832	35						181.00
833	73	0.40	12.24		3.60	1.44	68.60
834	67	2.40	34.40	14.40	0.80	7.00	84.30
835	76		3.00			3.30	35.20
836	67		174.48	60.75		12.00	246.30
837	61		66.20		4.30	12.00	363.10
839	67	0.30	2.60		-0.10	15.20	79.30
840	58		27.80		2.10	42.00	114.60
842	50		11.40	5.70	7.50	5. 10	144.98
843	69	1.84	9.24		18.50		209.06
845	57	0.30	3.10		0.60	1.80	40.80
846	46	18.80			1.20		1042.80
858	47	13.84	12.08		0.88		113.92
860	27	9.20					190.40
861	41	66.60	6.30				315.30
862	48		34.80		0.40	0.30	54.00
863	30		50.30		0.20	12.20	64.40
864	52		79.10		0.40	1.20	105.50
865	68		9.60		0.20	3.40	27.70
866	63		99.50	1.80		20.00	46.60
MEAN		5.20	32.99	4.18	2.17	7.22	170.03

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