4. Results of fishing operations

A summary of all fishing stations during the three surveys is as follows:

	Makran Coast			Sonmiani Bay Sind Coast
	Survey			Survey
	I	II	III	I	II	III
Bottom trawl
No. Stations	25	47	15	19	37	15
Mean catch kg.	1390	723	2206	2197	537	468
Pelagic trawl
No. Stations	6	1	4	8	10	7
Mean catch kg.	2356	430		517	490	167

One should note that the fishing operations as part of an acoustic survey first of all represent efforts to identify the resources. The results and especially the mean catches cannot therefore be interpreted as indications of catch rates of a commercial fishery. This would normally be concentrated in areas of the highest available catch rates. The results of this trial fishing particularly those from bottom trawling give, however, good indications of the composition of the fish resources and the highest catch rates may indicate the rates to be expected from a fishery.

When placed arbitrarily, bottom trawl hauls can also be used to estimate the total biomass of demersal resources. Such a system was worked during part of Survey II, and these data will here be used only for indicating the overall composition of the resources and not as indications of the catches.

4.1 Composition by families in pelagic trawl hauls

Table 1 shows the catch data for the 36 hauls with the pelagic trawl from all surveys. Jellyfish and a few incidental species are excluded. Hairtails, lantern fish, pony fish, sardine-like fish and jacks occurred in more than 20 percent of the hauls, but also anchovies had a wide occurrence. The bulk of the catches consisted of sardine-like fish and hairtails, 28% each, followed by ponyfish with 16%. The sardine-like fish also gave the highest mean catch, nearly 900 kg/hr. This was the result of two large catches of rainbow-sardine (Dussumieria acuta) off the Makran Coast. Catch rates in pelagic trawl is, however, of relatively limited interest. Also the catch composition will largely be determined by choice of targets for this type of aimed fishing. Thus in previous surveys anchovies have dominated the pelagic catches.

Table 1. Distribution of catches by families in 36 pelagic trawl hauls.

Family	% incidence in total no. of hauls	Mean catch	% of total catch
Sardine-like fish (Clupeidae)	22	868	28
Hairtails (Trichiuridae)	39	490	28
Ponyfish (Leiognatidae)	25	434	16
Lanternfish (Myctophidae)	39	125	7
Jacks (Carangidae)	22	126	4
Anchovies (Engraulidae)	14	155	3
Breams (Nemipteridae)	3	400	2

4.2 Composition by families in bottom trawl hauls, all surveys

An indication of the occurrence of the most common types of bottom fishes in the whole area of the Pakistan shelf is provided by Table 2, which includes the data from all the 157 bottom trawl hauls from all surveys. Hairtails is the most common form occurring in 3/4 of all catches and representing about 1/4 of the total catch. Croakers is found in about 60 percent of the catches and represent 14 percent of the total catch. Grunts follow with 70 percent occurrence and 10 percent of the total catch. These three families of fishes alone represent nearly 50 percent of the total catch. Also rays, catfishes, and breams have both a wide distribution and are relatively abundant, while jacks and seabreams also have a relatively wide distribution, but are less abundant. More than 14 other families are represented each within 1-2 percent of the total catches, some of which are commercially important, such as sharks, barracudas, groupers, congers etc.

Table 2. Distribution of most common family groups in catches of 157 bottom trawl hauls.

	% incidence in total no. of hauls	Mean catch	% of total catch
Hairtails (Trichiuridae)	74	344	24
Croakers (Sciaenidae)	61	243	14
Grunts (Pomadasyidae)	70	159	10
Rays	59	156	9
Catfishes (Ariidae)	57	153	8
Breams (Nemipteridae)	62	120	7
Jacks (Carangidae)	56	65	3
Seabreams (Sparidae)	64	50	3
Mean total catch		1054

4.3. Distribution and composition of bottom trawl catches, Makran Coast

Table 3 gives the composition of catches by family groups and by sizes of catches from Survey I. Also the mean catch of various types of fish and the means by depth strata is estimated, together with the overall mean.

Table 3. Distribution of catches by family groups, Makran Coast, Survey I. Demersal trawl.

		% incidence in total no. of hauls	Mean catch	% of total catch	Mean catch in bottom depth strata
					No. hauls:
					7	14	4	0
					<20m	20-50m	50-100m	>100m
Hairtails (Trichiuridae)		96	935	73	75	1165	1394	0
Croakers (Sciaenidae)		76	220	14	34	137	502	0
Catfishes (Ariidae)		72	42	2	71	18	2	0
Grunts (Pomadasyidae)		60	47	2	30	34	0	0
Rays		52	50	2	55	19	0	0
Seabreams (Sparidae)		56	48	2	38	25	12	0
	Congers	16	87	1	20	15	0	0
	Groupers	40	22	1	4	11	9	0
Sharks		28	25	1	2	11	1	0
Shrimp		20	34	1	1	12	0	0
Other fish			37	1
Mean total catch			1247		361	1491	1943	0

The by far dominant group is hairtails occurring in nearly all catches and representing more than 70 percent of the total catch. The highest mean catches about 1.4 tonnes are obtained in the depth strata 50-100 m. Also most of the other groups listed are widely distributed, but only croakers represent an appreciable part of the catch, 14 percent, again with highest catch rates in the 50-100 m depth range. The overall mean catch is 1.2 tonnes/hr., but nearly 2 tonnes/hr. in the 50-100 m depth range. The three highest catches about 9 tonnes/hr., 6.7 tonnes hr. and 6.3 tonnes/hr. consisted of hairtails.

Table 4 gives similar data for Survey III. Again hairtails and croakers are most common and abundant, but catfishes and grunts also make up appreciable parts of the catches followed by rays, seabreams and threadfin breams. The mean total catch rate was 2.2 tonnes, but with higher catch rates in the shallow water range (<20 m). The highest catch rates included two of 7.5 tonnes/hr. of hairtails, croakers and others and two of 4 tonnes, one of hairtails, croakers and others and one of grunts, false trevally and others, all in shallow waters.

Table 4. Distribution of catches by main family groups, Makran Coast, Survey III. Demersal trawl.

	% incidence in total no. of hauls	Mean catch	% of total catch	Mean catch in bottom depth strata
				No. hauls:
				5	8	2	0
				<20m	20-50m	50-100m	>100m
Hairtails (Trichiuridae)	87	725	29	343	995	51	0
Croakers (Sciaenidae)	87	478	19	375	531	45	0
Catfishes (Ariidae)	67	396	12	207	391	0	0
Grunts (Pomadasyidae)	80	254	9	340	169	0	0
Rays	87	109	4	88	122	2	0
Seabreams (Sparidae)	73	104	4	159	44	0	0
Threadfin breams (Nemipteridae)	27	224	3	0	3	437	0
Shrimp	33	168	3	1	105	0	0
False trevallies (Lactaridae)	73	67	2	85	33	0	0
Pike congers (Muraenesocidae)	60	80	2	55	62	3	0
Groupers (Serranidae)	47	101	2	80	48	2	0
Mean total catch		2207		3118	1971	869	0

4.4 Distribution and composition of bottom trawl catches, Sonmiani Bay and Sind Coast

Table 5 gives the distribution by families of the bottom trawl hauls from this eastern part of the Pakistan shelf during Survey I.

Table 5. Distribution by family groups, Sind Coast, Survey I, demersal trawl, 19 hauls.

	% incidence in total no. hauls	Mean catch	% of total catch	Mean catch in bottom depth strata
				No. of hauls:
				2	7	7	3
				<20m	20-50m	50-100m	>100m
Croakers (Sciaenidae)	79	638	23	118	724	597	30
Grunts (Pomadasyidae)	47	966	21	9	868	371	0
Rays	32	963	14	0	134	691	0
Hairtails (Trichiuridae)	63	330	10	6	152	413	0
Catfishes (Ariidae)	21	572	6	3	326		0
Jacks (Carangidae)	32	293	4	0	90	161	0
Threadfinns (Polynemidae)	37	255	4	6	222	31	0
False trevally (Lactaridae)	47	129	3	3	99	66	0
Breams (Nemipteridae)	53	122	3	0	14	149	25
Indian halibuts (Psettodidae)	21	289	3	0	108	57	0
Seabreams (Sparidae)	26	130	2	0	76	17	0
Mean of total catch		2197		181	3066	2753	216

In these catches croakers and grunts dominate (together 44 percent) and are also widely spread on the shelf. Rays and hairtails are also common followed by catfishes and jacks. The mean total catch rate is 2.2 tonnes/hr. but about 3 tonnes/hr. in the depth ranges 20-50 m and 50-100 m. The highest catch rates, 16 tonnes/hr. were obtained in two hauls off the Indus delta giving mainly croakers, grunts and hairtails.

Table 6 shows the catch data for the most common groups in Survey III. Compared with Survey I catch rates are very low, reduced by 3/4 or 4/5.

Table 6. Distribution by family groups, Sind Coast, Survey III, demersal trawl, 15 hauls.

	% incidence in total no. hauls	Mean catch	% of total catch	Mean catch in bottom depth strata
				No. of hauls:
				1	4	7	3
				<20m	20-50m	50-100m	>100m
Threadfin breams (Nemipteridae)	60	172	22	0	0	122	230
Hairtails (Trichuridae)	87	80	15	1	157	38	48
Croakers (Sciaenidae)	40	137	12	82	185	0	8
Anchovies (Engraulidae)	27	83	5	0	83	0	0
Grunts (Pomadasyidae)	60	35	5	21	22	29	1
Catfishes (Ariidae)	47	38	4	12	62	1	1
Jacks (Carangidae)	67	30	4	0	5	27	30
False trevally (Lactaridae)	33	38	3	0	42	3	0
Pony fish (Leiognatidae)	47	30	3	0	2	22	15
Rays	47	31	3	12	47	0	3
Sharks	53	23	3	0	33	8	0
Snappers (Lutjanidae)	20	44	2	0	21	0	15
Lizardfish (Synodontidae)	47	24	2	0	0	20	7
Mean of total catch		468		183	812	340	404

Threadfin breams, hairtails and croakers are most common and represent about 50 percent of the catch, but a very large number of other groups, more than 27 are represented in the catches. The indications are that at this season, even the forms of high abundance are not found in aggregations. The highest catch rates 1.5, 1.0 and 0.7 tonnes pr. hour were obtained in Sonmiani Bay giving hairtails, threadfin breams and croakers.

4.6 Discussion of the composition of the fish fauna of the Pakistan Shelf

Judged by the limited information from the fishing trials with pelagic trawl, sardine-like fish, hairtails, ponyfish and anchovies represent the bulk of fish found in mid-water. Previous surveys have as mentioned above shown anchovies to be perhaps the most abundant component of the pelagic community. There is, however, no clear distinction of forms belonging to the pelagic and the demersal communities, especially in shallow waters. Hairtails, ponyfish, jacks and anchovies are commonly caught both in pelagic and in demersal trawls.

The most common group of fish on the Pakistan shelf is the hairtails. They dominate the bottom trawl catches especially on the Makran Coast with relatively high catch rates, means frequently exceeding 1 tonne/hr. both in the post-monsoon (1st survey) and monsoon-period (3rd survey). Hairtails occur commonly also on the eastern part of the shelf, but in less abundance, particularly in the monsoon period when bottom fish in general seems inclined to scatter.

The next most common form along the whole coast is croakers for which mean catch-rates at times exceeded 500 kg/hr. The third place in distribution and abundance is more or less shared between grunts, rays, catfishes and threadfin breams. Other important representatives in the fauna with a wide distribution, but less general abundance are sea breams, jacks, congers, groupers, sharks and snappers. Shrimps occur in many catches, but the type of trawl used is not well adapted to shrimp fishing and the data are thus not suited for an analysis of this commercially important group.