3.1 SURINAME

3.1.1 Small pelagic fish
3.1.2 Demersal resources
3.1.3 Overview and discussion of survey results

Figure 3.1.1 shows the course tracks and fishing stations in the area.

3.1.1 Small pelagic fish

Distribution

Figure 3.1.2 shows the distribution of the pelagic fish as observed with the acoustic integrations system for each of the surveys in January-February, May, August and October-November. Small pelagic fish, particularly engraulids and smaller clupeids are low in the food chain and their distribution is often closely related to areas of high primary and/or secondary production. As described in chapter 2 above, conditions for high primary production on the Guianas shelf are created by upwelling of intermediate water from the slope region and in part by discharges of the many rivers. The main concentrations of small pelagic fish were also mainly located in the cool inshore upwelled water which is also close to the river mouths. Most of the biomass of small pelagic fish was found in the water column above the thermocline. From the distribution charts it is evident that the assemblage of small pelagic fish is mainly restricted to the inner shelf area throughout the year, but with a somewhat more offshore distribution found in the May survey. A characteristic of the assemblage is that it consists of a relatively large number of species from three main families engraulids, clupeids and carangids. These are accompanied by large sized predators, barracudas, scombrids, and sharks in the pelagial. The distribution of demersal fish are also in a general way affected by that of the small pelagics which must represent their main food source.

While the main bulk of the small pelagic fish as observed by the acoustic system is found over the inner parts of the shelf, the outer shelf from about 50 m to the edge at about 100 m of depth was found to hold smaller amounts of pelagic fish in low densities distributed in small schools and aggregations. This assemblage differed in species distribution from that of the inner shelf with an absence of engraulids and with the clupeids represented nearly exclusively by adult Sardinella aurita and the carangids by the rough scad Trachurus lathami, the big-eye scad Selar crumenophthalmus, bumper and lookdowns. In terms of biomass this assemblage is of little importance, but the catches are analysed separately below to show the difference in compositions.

The distribution of small pelagic fish in the western Suriname shelf was usually found to have a continuous extention into Guyana and this means that the stocks in question to some degree are shared between the two countries.

Catch compositions

Pelagic types of fish often formed substantial parts of the catches in the hauls made with bottom trawl for swept area estimates and otherwise fishing for identification and sampling of pelagic types of fish was made both with demersal and mid water trawls. These data can add to our picture of the general occurrence and composition of the various groups and species, but they must be interpreted with caution. The catchability of these gears are often highly species and size selective. Some clupeids such as large sized schooling sardinella and thread herrings has for instance a low catchability while anchovy, smaller carangids such as bumper and scads and more solitary species such as Spanish mackerel and barracudas are more easily caught both at the bottom and in mid water. This difference in catchability detracts from the value of the records of the catches in describing the resource composition and this reservation should be kept in mind.

Complete catch records and various types of processed outputs giving catches by groups, species and surveys are available in the DATA FILE ANNEX to this report. Here we will only show some brief extracts of the catch data.

Figure 3.1.1. Suriname, Guyana and Venezuela, Orinoco. Course tracks and fishing stations, by surveys.

SURVEY 1: 21.1 - 7.2 1988

SURVEY 2: 6 - 22.5 1988

SURVEY 3: 9 - 23.8 1988

SURVEY 4: 29.10 - 11.11 1988

Figure 3.1.2. Suriname, Guyana and Venezuela, Orinoco. Fish distribution as recorded by the acoustic system, by surveys.

SURVEY 1: 21.1 - 7.2 1988

SURVEY 2: 6 - 22.5 1988

SURVEY 3: 9 - 23.8 1988

SURVEY 4: 29.10 - 11.11 1988

Tables 3.1.1 and 3.1.2 shows the mean catch rates in kg/hour, the three highest rates obtained and the incidence of occurrence by families and surveys and for the inner and outer shelf parts separately. Engraulids and clupeids show the highest rates on the inner shelf, carangids on the outer. There is a considerable variation through the year with particularly low rates for all groups in the August survey. For the short-lived anchovies this could be an effect of an annual production cycle. The biomass estimates show similar low values for this survey and the most likely explanation is a combination of a production cycle and movement out of the area covered by the survey, either into shallow inshore waters or southeast along the shelf. The low availability in August coincides with the summer season of reduced upwelling and a deeper and more pronounced thermocline.

Table 3.1.1 Suriname. Pelagic fish. Inner shelf. Catch rates in kg/hour by main groups by surveys. Mean rate, three highest rates and rate of occurrence.

Survey	Mean rate	Highest rates			Rate of occurrence
ENGRAULIDS
1 January	176	1764,	448,	230	16/21
2 May	46	512,	146,	133	10/23
3 August	40	274,	204,	146	5/17
4 Oct.-Nov.	113	1311,	644,	212	15/24
CLUPEIDS
1 January	152	1320,	497,	283	19/21
2 May	128	1369,	618,	536	18/23
3 August	52	314,	220,	169	11/17
4 Oct.-Nov.	152	1440,	644,	443	19/24
CARANGIDS
1 January	75	1057,	148,	86	18/21
2 May	77	948,	234,	180	22/23
3 August	31	154,	116,	82	17/17
4 Oct.-Nov.	39	311,	154,	101	22/24
SCOMBRIDS
1 January	7	44,	20,	16	15/21
2 May	25	185,	83,	69	15/23
3 August	5	35,	26,	8	9/17
4 Oct.-Nov.	22	103,	57,	53	18/24
BARRACUDAS
1 January	22	147,	137,	113	9/21
2 May	39	810,	54,	19	9/23
3 August	5	34,	19,	16	7/17
4 Oct.-Nov.	11	142,	83,	14	11/24
HAIRTAILS
1 January	37	195,	188,	162	11/21
2 May	65	905,	382,	78	9/23
3 August	6	74,	24,	8	4/17
4 Oct.-Nov.	24	263,	75,	58	13/24

Table 3.1.2 Suriname. Pelagic fish. Outer shelf. Catch rates in kg/hour by main groups by surveys. Mean rate, three highest rates and rate of occurrence.

Survey	Mean rate	Highest rates			Rate of occurrence
CLUPEIDS
1 January	13	93,	80,	22	12/17
2 May	17	135,	82,	56	7/17
3 August	2	7,	4,	2	5/8
4 Oct.-Nov.	6	64,	6,	5	8/14
CARANGIDS
1 January	71	234,	225,	199	17/17
2 May	113	499,	236,	212	15/17
3 August	13	43,	39,	10	5/8
4 Oct.-Nov.	99	582,	283,	201	14/14
SCOMBRIDS
1 January	6	59,	11,	10	8/17
2 May	10	84,	47,	14	6/17
3 August	4	29,	6,	0	2/8
4 Oct.-Nov.	4	18,	8,	8	8/14
BARRACUDAS
1 January	4	21,	15,	13	8/17
2 May	7	91,	15,	11	5/17
3 August	1	5,	0,	0	1/8
4 Oct.-Nov.	2	11,	8,	5	6/14

Table 3.1.3 shows the composition by main species within families using the mean proportion by weight of all catches compiled for each survey.

Table 3.1.3 Suriname. Species distribution by families of small pelagic fish. Catch by weight of species by surveys as per cent of total catch of family.

Survey:	1	2	3	4	Mean
ENGRAULIDS
Mean catch, kg/hour	176	46	40	113
Anchoa spp.	78	13	88	20	50
Anchoviella spp.	7	48	12	28	24
Engraulis spp.	15	18		49	21
Lycengraulis spp.		21			5
CLUPEIDS
Mean catch, kg/hour	98	97	36	109
Opisthonema oglinum	54	21	8	5	22
Sardinella aurita	14	11		3	7
Pellona harroweri	8	39	14	16	19
Chirocentrodon bleekerianus	3	13	63	70	37
Harengula jaguana		16	12	1	7
Odontognathus spp.	16			4	5
CARANGIDS
Mean catch, kg/hour	73	92	27	62
Chloroscombrus chrysurus	14	45	21	26	27
Selene spp.	44	1	21	21	22
Trachurus lathami	18	23		32	18
Hemicaranx amblyrhyncus	2		14	9	6
Selar crumenophthalmus	13	11	7		8
Decapterus punctatus	1	8		1	2
Decapterus macarellus		7		3	2
Trachinotus spp.			31	2	8
Oligoplites spp.				5	1

The Anchoa genus dominate the engraulids with three main species A. lyolepis, A. spinifer and A. hepsetus. Anchoviella lepidentostole and Engraulis eurystole were identified from the other genera. Among the clupeids the sardinella was mainly found on the outer shelf and the three species: thread herring, pellona and dogtooth herring dominated the inner shelf. The bumper was consistently the most common carangid followed by lookdowns. The rough and the big-eye scads were more offshore species while the other forms occurred more incidentally.

The scombrids consisted of the two species, king mackerel Scomberomorus cavalla and serra S. brasiliensis with the last form as the most common contributing 64% of the total Spanish mackerel catch. They were found in highest abundance on the inner shelf apparently related to the availability of prey species.

Also the barracudas were represented by two species with guachanch barracuda Sphyraena guachancho occurring about 6 times as frequent as the southern sennet Sphyraena picudilla which, however, produced an occasional very high catch. The barracudas were roughly three times more abundant in the inner than in the outer shelf.

The hairtails consisted of only one species the largeheaded hairtail Trichiurus lepturus and it was found nearly exclusively on the inner shelf.

Biomass estimates

The estimates of biomass based on the acoustic observations are shown in Table 3.1.4. As described under chapter 1 above a separation into two groups of fish is attempted during the processing of the data, Pelagic I consisting of engraulids and clupeids and Pelagic II which mainly includes carangids, scombrids, barracudas and hairtails. This separation is partly based on the catch compositions partly on characteristics of behaviour in relation to forms of aggregations and the results will only be an approximation of the proportions between the groups.

The estimates of total biomass vary through the year with a factor of more than three with particular low values for the August survey. The catch rates for the various groups show a roughly similar variation and this indicates variations not only in total abundance but also in the densities of the forms.

Table 3.1.4 Suriname. Estimates of standing biomass of pelagic fish by surveys and groups. 1 000 tonnes.

Survey	Pelagic 1	Pelagic 2	Total
1 January	520	240	760
2 May	310	240	550
3 August	170	30	200
4 Oct.-Nov.	240	140	380

The likely cause of the variations is as discussed above a combination of an annual production cycle and fish migrations, both of which may be related to seasonal changes in the hydrographic regime. One should note that during survey 4 in October-November most of the schooling pelagic fish consisted of juvenile forms still at stages where increase of biomass through growth was likely to be greater than the loss from mortality.

For the purpose of estimating standing stock biomass it is proposed to disregard the summer season of low availability and use the average of the first two and the last survey. Such calculations give a total biomass of pelagic fish of 550 000 tonnes of which 360 000 tonnes is engraulids and clupeids and 200 000 tonnes carangids and others.

A further rough breakdown of these group estimates may be obtained by use of the proportions of the total catches between families and for the surveys 1, 2 and 4. The probable bias caused by differences in catchability between sizes and species should, however, be kept in mind. These calculations give the following breakdown:

Engraulids	130 000	tonnes
Clupeids	230 000	tonnes
Carangids	120 000	tonnes
Scombrids	20 000	tonnes
Barracudas	25 000	tonnes
Hairtails	35 000	tonnes

It seems likely that the more solitary scombrids and barracudas have a higher catchability than the true schooling pelagic forms. If so, their biomass is overestimated here. Swept area estimates of these groups give 7 000 tonnes for each of them and 11 000 tonnes for hairtails. Since these species are also well known mid water inhabitants they will be underestimated by the swept area method. The mean of the two estimates could perhaps be used as the best estimate of stock biomass i.e. 14 000 tonnes of Spanish mackerels, 16 000 tonnes of barracudas and 23 000 tonnes for hairtails.

3.1.2 Demersal resources

The main source of data for the analysis of the demersal resources is from the random bottom trawl stations carried out. For the Suriname shelf this material comprises 35, 37, 24 and 30 stations from the four coverages respectively. The slope was investigated to a much lesser intensity, with only 8 stations throughout the year. In the analysis below the datasets have been analysed by two bottom depth strata: 0-50 m and 50-120 m which are termed inner and outer shelf respectively. Below only the highlights from the analysis with the main commercial species or species groups are commented upon in the text The complete results from the analysis are included in Annex 7 of the DATA FILE.

Demersal fish

The main demersal species groups in Suriname waters are snappers, croakers and grunts. The outer shelf is clearly dominated by snappers, while the inner shelf in addition holds important resources of croakers and grunts.

The main species are for the inner shelf: lane snapper L. synagris, Corocoro grunt Orthopristis ruber, king weakfish Macrodon ancylodon, acoupa weakfish Cynoscion acoupa, dwarf goatfish Upeneus parvus, American harvestfish Peprilus paru and Jamaica weakfish Cynoscion jamaicensis in decreasing order of quantity. For the outer shelf the main species are vermillon snapper Rhomboplites aurorubens, southern red snapper L. purpureus and cardinal snapper Pristipomoides macrophthalmus.

The demersal fish has a continuously distribution on the Suriname-Guyana shelf. The stocks are thus shared, but to what extent is uncertain. A preliminary study of the snapper stocks indicates that a seasonal migration may take place in summer from the offshore Suriname shelf into more inshore Guyanese waters. Further analysis of the survey data should be made to study distribution patterns.

Catch composition

As most of the trawl hauls are randomly located for the purpose of swept area estimates, they will not be representative for aimed fishery at targeted species and locations. The highest catches may, however, be representative for a fishery and the mean catch might serve as indicators of minimum catch rates in a wide scale multi-species fishery.

Table 3.1.5 shows the mean catch rates by surveys in kg/hour and the total catch distribution by size classes for the main demersal species in Suriname waters.

Table 3.1.5 Suriname. Mean catch rates and catch distribution by size classes of main species in all hauls.

Species		Mean rate	Number of hauls in catch groups						Rate of occurr.
		kg/hour	1-30kg	30-100	0.1-0.3t	0.3-1t	1-3t	>3t
INNER SHELF 0-50 m
	Lane snapper	47	34	7	5	2	1		49/81
	Corocoro grunt	40	13	2	2		2		19/81
	King weakfish	14	10	6	4				20/81
	Acoupa weakfish	12	10	1		1			12/81
	Dwarf goatfish	8	42	6	2				50/81
	Americ. harvestfish	7	38	5	1				44/81
	Jamaica weakfish	8	16	3	2				21/81
OUTER SHELF 50-120 m
	Vermillon snapper	63	41	13	11	1			66/126*
	South. red snapper	23	31	8	4				43/126*
	Cardinal snapper	17	43	5	3				51/126*

* Catch distribution and rate of occurrence for whole shelf (0-120 m).

By main groups the mean catch rates were:

INNER SHELF: 0-50 m
Snappers	60 kg/h
Grunts	50 kg/h
Croakers	62 kg/h
OUTER SHELF: 50-120 m
Snappers	108 kg/h

Biomass estimates

Estimates of fish density by depth strata are given in the DATA FILE of Annex 8. By multiplying these densities with the area of the shelf, shown in Table 2.3.1. depth stratified estimates of standing biomass are obtained by surveys and species or species groups. These estimates are presented for the main groups in Table 3.1.6.

Table 3.1.6 Suriname. Estimates of biomass of demersal fish by main groups and surveys.

		Survey 1	Survey 2	Survey 3	Survey 4	All surveys
INNER SHELF
	Snappers	9 500	38 000	15 000	23 000	22 000
	Grunts	4 000	5 000	37 000	31 000	18 500
	Croakers	37 500	15 000	21 500	16 000	22 500
	Other demersal	25 000	55 000	32 000	37 000	40 000
OUTER SHELF
	Snappers	16 000	13 000	17 000	19 500	16 000
	Other demersal	5 500	5 000	9 000	5 000	6 000
TOTAL SHELF
	Snappers	25 500	51 000	32 000	42 500	38 000
	Grunts	4 000	5 000	37 000	31 000	18 500
	Croakers	37 500	15 000	21 500	16 000	22 500
	Other demersal, mostly non comm.	30 500	60 000	41 000	42 000	46 500

The table shows strong fluctuations between surveys for all groups on the inner shelf, while the outer shelf shows more stable conditions. In most cases where high estimates on the inner shelf are obtained this is due to one or two extraordinary high catches of the species group. This reflects a high patchiness of the fish distribution which will give high sampling variance and wide confidence limits of the estimates. It is thus likely that the varying estimates in the table more reflects the distribution pattern of the fish than actually seasonal fluctuations in biomass. The estimates based on all surveys are less subject to coincidental high catches, and these estimates are thus more reliable. Using these data we obtain a total biomass estimate of snappers, grunts and croakers of 78 000 tonnes. Most of this represent fish of commercial interest although the value differs between species and sizes. In addition there is an estimated 46 000 tonnes of other demersal fish most of which is non-commercial. For some stocks there may be a special bias towards an underestimate in the results presented above. Thus the snappers, particularly perhaps the larger species are known to aggregate over hard bottom offshore which would make them less vulnerable to trawl sampling. We had expected to be able to locate such aggregations by echo sounder and conduct line fishing tests on the basis of the experience from the “CALAMAR” surveys 1967-70 but, in spite of the extensive coverage, recordings of this type were few and with low densities. This may indicate that this source of bias for our standing stock estimates is not of very great importance.

Sharks

Table 3.1.7 shows an analysis of the catch data for sharks by surveys. The highest catches were taken on the inner shelf and often together with large catches of small pelagic fish which represent the most important prey species. The mean catch rates were low, a consequence first of all of the restricted distribution on the shelf, demonstrated by the low rates of incidence. A swept area estimate based on the data from all the surveys gives a biomass of 5 000 tonnes. This is likely to be a considerable underestimate since sharks have a semi-pelagic behaviour.

Table 3.1.7 Suriname. Sharks. Catch rates in kg/hour by main groups by surveys. Mean rate, three highest rates and rate of occurrence.

Survey	Mean rate	Highest rates			Rate of occurrence
1 January	10	87,	68,	25	18/32
2 May	9	106,	86,	30	12/37
3 August	14	105,	71,	32	9/19
4 Oct.-Nov.	5	32,	24,	20	21/37

Table 3.1.8 shows the composition by main groups based on the proportion in the total catch. The smalltail shark Carcharhinus porosus and the night shark C. signatus were the most common of the requiem sharks, the Caribbean sharpnose shark Rhizoprionodon porosus was by far the most common of this group and the scalloped hammmerhead Sphyrna lewini dominated this group. The incidence was low for all species, 3-6% except for the Carribbean sharpnose which occurred in 24% of all shelf hauls. The size of the specimens caught were generally small, even for the hammerheads and requiem sharks which may attain a large size. This is likely to be an effect of the fishing method, a slow moving trawl at the bottom.

Table 3.1.8 Suriname. Sharks. Proportion by weight in catch, range of sizes and percentage occurrence in all catches.

		Catch %	Range of size, kg.	Incidence %
Requiem sharks,	Carcharhinus spp.	18	1 - 10	3 - 6
Sharpnose sh.,	Rhizoprionodon spp.	59	0.5 - 3	3 - 24
Hammerheads,	Sphyrna spp.	18	0.5 - 3	4 - 5
Smooth-hounds,	Mustelus spp.	5	1	2 - 6

Squid

Small sized shelf squid were caught in bottom trawl in daylight hauls, mostly in the depth range 20-50 m. Table 3.1.9 shows the catch data which include estimates of the mean rate from the hauls where present, which might better reflect the seasonal changes in availability. The catch rates are small or modest, the highest recorded from the May survey. The distribution tended to be patchy and special “squid grounds” may exist. 95% of the catch of squid on the shelf consisted of Loligo species with L. plei dominating and with smaller amounts of L. pealei, somewhat uncertain because of taxonomic difficulties. Sizes ranged from 5-20 cm mantle length, but not exceeding 10 cm in the August survey. A swept area estimate gives a mean standing biomass of about 3 000 tonnes based on the data from all four surveys. There is likely to be an annual cycle in the biomass of these species with levels considerably higher than this estimate, probably during the first half of the year. A biomass estimate of 1 400 tonnes was obtained in a Japanese survey, 1982-83 (Inada and Mito, 1983)

Table 3.1.9 Suriname. Squid. Inner shelf. Catch rates in kg/hour by main groups by surveys. Mean rate for all hauls and where present, three highest rates and rate of occurrence.

Survey	Mean rate		Highest rates			Rate of occurrence
	All	Where pres.
1 January	4	12	44,	4	33	5/15
2 May	15	27	95,	84,	42	11/20
3 August	8	15	58,	14,	12	8/15
4 Oct.-Nov.	6	11	30,	25,	22	15/23

Shrimp

Shallow water shrimp. As discussed at the planning meeting the objectives of the programme did not include comprehensive coverage of the shallow water shrimps as this would have required a separate extensive effort. Some incidental observations were, however, made and these will be briefly reported on below.

The behaviour and distribution of the shrimps differ by species. Thus the brown shrimp Penaeus subtilis and the white shrimp P. schmitti have highest catchability in shallower parts of the shelf in daytime, while the red spotted shrimp P. brasiliensis is generally found deeper and give highest catches during the night. The pink shrimp P. notialis appeared in catches both at daytime and during the night. Because of the restricted data and the behaviour differences the analysis of the catch data has for this group been limited to the hauls in which the relevant species appeared. These data may be used to demonstrate relations between species and surveys, but not for estimates of biomass. The number of hauls made in the shrimp areas vary considerably from survey to survey with regard to depth and time of day. In order to obtain a comparable series of data an attempt has been made to convert the catch data to correspond to an equal number (20) of day and night hauls for each survey.

The data obtained on the small sized seabob Xiphopenaeus kroyeri and the white belly prawn Nematopalaemon schmitti have not been included in the analysis. They appeared sporadically with often high catch rates, but it is believed that the surveys only covered a smaller outer part of their more inshore distribution.

Table 3.1.10 shows the catch data for the four penaeid shrimp species for Suriname. The brown shrimp dominate in all surveys, but this may partly be an effect of an incomplete coverage of the medium shelf at night. Catch rates are low except for the second survey which is affected by a single haul in which 50 kg was caught in 12 minutes. If this observation is discounted there is no seasonal trend in catch rate, but the size compositions (see DATA FILES) suggest recruitment in January and in August. The size of the samples of red spotted shrimp varied little through the year.

It is thought that the survey data could provide a good basis for studies of the fish by-catch in the shrimp fisheries.

Table 3.1.10 Suriname. Shallow water shrimps. Mean catch rates in hauls where present and highest rates by surveys, mean rates for all surveys and by day/night, kg/hour. Total catch adjusted to a standard survey effort for all surveys.

	Brown	Red spotted	White	Pink
1 January	4 (19)	2
2 May	123 (240)	2		2
3 August	4 (7)	4 (7)	10
4 Oct.-Nov.	3 (6)	3 (4)		1
All surveys	14	2	3	1
All surveys day	20.3	0.7	3.3
All surveys night	2.6	2.1	0	1.0
Adjusted catch	340 kg	150 kg

Deep water shrimp. The deep water shrimp off Suriname and French Guyana was surveyed thoroughly by the Japanese “Nisshin-Maru no 201”- programme in 1982-83 (Inada and Mito 1983). In our survey only a small number of test hauls were made. The results demonstrated the presence of the scarlet shrimp Plesiopenaeus edwardsianus, shrimp in 7 out of nine hauls, with a mean catch rate of 8 kg/hour and the three highest rates 20, 20 and 11 kg/hour. The highest catches were taken in 700-770 m depth and sizes were good. One set of tests from the Japanese survey showed highest rates between 800 and 900 m, a depth range which we could not cover, but otherwise our observations fall into the range of those obtained in that survey.

3.1.3 Overview and discussion of survey results

The following groups of resources were identified and will be discussed:

Small pelagic fish was found aggregated in areas over the inner shelf where they occurred in schools and layers. Fish densities were high and the areas extensive in all except the third survey. This assemblage consisted of a large number of species from three main families, engraulids, clupeids and carangids accompanied by larger sized predators, barracudas, scombrids and sharks in the pelagial. Lower densities of pelagic fish was found over the outer shelf consisting of fewer species, mainly round sardinella, rough scad and other carangids. Pelagic fish formed an important component of the catches also in the bottom trawl hauls. Catch rates were generally low in the August survey.

Demersal fish occurred in highest abundance on the inner shelf, the most important commercial groups being snappers, grunts and croakers. Various species of snappers dominated the outer shelf.

Sharks occurrence in the catches seemed to be associated with that of its main prey, small pelagic fish, but catch rates were modest and incidence low.

Shrimps. Only incidental observations are presented on the important resources of shallow water shrimps. For deep sea shrimp the results of some fishing tests are available.

Squid was found in modest amounts in the mid shelf consisting mainly of small Loligo species. The highest catch rates were obtained in the May survey.

Table 3.1.11 shows a summary of the assessments of the standing stock of the various groups. Some of these are likely to be underestimates e.g. those for sharks and perhaps the red snapper. With a total biomass of 680 000 tonnes and a shelf area of 15 000 nm² the mean density of biomass of the Suriname shelf is 45 t/nm² which indicates a fairly high productivity.

Summarized data are available on the findings from a number of previous trawl surveys of the Suriname shelf. In order to compare the resulting estimates of standing biomass the same catchability coefficient must be applied in the calculations. In Table 3.1.12 the results for each survey have been converted to the use of q = 1. There is a considerable variation between the results. Some of this could be caused by differences in survey methodology, thus surveys targeting on shrimp may have a high proportion of night hauls which will give a bias towards low fish catches. The groups of fish included may also vary between surveys. The comparison may, however, demonstrate a real decline of demersal fish biomass on the outer shelf over the long period from the 1960ies up to present. These offshore grounds must have held accumulated virgin stocks at that time. In general, however, our results fall reasonably into the ranges of the previous findings.

A comparison between our data on catch composition of demersal fish with that from the “BONITO” survey indicate that the proportion between main groups may have changed. The sea catfishes which after the croakers were the most important group in the “BONITO” catches appeared with only very low density in our catches.

In order to maintain the fish stocks as a lasting resource only a part of the standing stock can be fished. The proportion of this long term yield varies between types of fish, and existing fisheries must also be taken into account in calculating the total potentials. In the following we will use 40% for small pelagic fish and 20% for demersal fish and the larger sized pelagics such as barracudas, Spanish mackerels and hairtails. These proportions are based on the assumption that the demersal and larger sized fish are moderately exploited at present.

The official catch statistics for Suriname does not include a breakdown of the total catch on species or species groups of fish. One must assume that in addition to the reported 1987 catch of about 4 000 tonnes of marine finfish, the fish by-catch in the shrimp fisheries may exceed this by a considerable amount. On the assumption, however, that the main demersal fish stocks are only moderately exploited, the potential yield at 20% of the standing biomass would be 16 000 tonnes of snappers, grunts and croakers and about 10 000 tonnes of Spanish mackerels, barracudas and hairtails. Not all of the species included in these groups are of equal commercial interest, e.g. the small sized snappers and the grunts are probably of less value than the large sized red snapper. A more detailed analysis of the state of the stocks of highest commercial importance should be made on the bases of additional information on catches by species, size compositions etc. In addition there would be a considerable potential of small pelagic fish, mainly engraulids and clupeids if a fishery could be developed on these types of low-value resources. One should note that in a management sense the stocks are to some extent shared with Guyana.

Table 3.1.11 Suriname. Summary of estimates of standing stock biomass. Tonnes.

Pelagic fish
	Engraulids	130 000
	Clupeids	230 000
	Carangids	147 000
	Scombrids	14 000
	Barracudas	16 000
	Hairtails	23 000
	Total		550 000
Demersal fish
	Snappers	38 000
	Grunts	18 500
	Croakers	22 500
	Other demersal mostly non-com.	46 500	126 000
Sharks			5 000
Squid			3 000
Shallow water shrimp
Deep water shrimp
Total			684 000

Table 3.1.12 Suriname. Comparison of estimates of standing biomass from various surveys with calculations adjusted to a catchability coefficient q = 1. Sources: Klima (1976), Fabres (1980) and Losse (1982).

Survey:	Inner shelf	Outer shelf	Total
Coquette (1962-65)	169 000	83 000	252 000
Calamar (1967-68)	91 000
La Salle (1969)	74 000
Oregon II (1972-77)		72 000
Bonito (1980-81)	105 000
Dr Fridtjof Nansen	128 000	22 000	150 000