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.
Guatemala.
The records of all the fishing stations made during this part of the cruise are shown in Annex 2, where those numbered from 163 through 188 refer to the area off Guatemala (cfr. Figure 1). Most of the trawl stations in the inshore area represent prelocated hauls for faunistic studies and swept area estimates and they are thus not representative for a commercial fishery which would concentrate on the grounds with highest catches. The catch rates in these hauls were still quite good ranging from abt 100 to about 1600 kgs/hr with a mean of 600 kgs/hr. A pelagic trawl haul on sardine gave a rate of abt 2 tons per hour. The inshore catches consisted of a mixture of scads, sardines, barracudas, anchovies and others with some dominated by demersal fish, grunts and snappers (st. 174, 176 and 185). Some of the shallow water hauls gave small catches of large sized penaeid shrimp.
Fishing offshore was primarily arranged to cover different depths between abt 100 and abt 350 m in testing for langostino and shrimp. Table 1 shows the results of these trials. The four fishing stations made east of the deep water canyon off San Jose gave almost no catch. Further west there were good catches of langostino in depths varying from 110 to 250 m. There is no regular variation of mean size of the langostino with depth, but the two hauls with lowest size were from shallow depth (st 173 and 182). Very little deep water shrimp was caught in these hauls. For reasons of utilizing survey time all deep water fishing has been done at night and it is uncertain whether this can have affected shrimp catches.
Table 1. Catches of langostino and shrimp, offshore, Guatemala
|
Station no |
Depth m |
Langostino |
Shrimp kgs/hr |
|
|
tons/hr |
mean weight |
|||
|
163 |
180 |
0.1 |
10 gr |
|
|
164 |
250 |
|
|
45 |
|
165 |
260 |
|
|
|
|
166 |
100 |
|
|
|
|
170 |
160 |
0.5 |
22 gr |
|
|
171 |
250 |
1.3 |
15 gr |
28 |
|
172 |
350 |
|
|
|
|
173 |
150 |
1.0 |
8 gr |
|
|
179 |
110 |
|
|
|
|
180 |
180 |
0.25 |
14 gr |
|
|
181 |
200 |
3.1 |
11 gr |
|
|
182 |
110 |
0.6 |
5 gr |
|
|
188 |
170 |
1.1 |
10 gr |
|
Table 2. Testing for oceanic squid (Dosidiscus gigas) with light and jigging, Guatemala.
|
Date
|
Hour
|
Latit. |
Longi. |
Depth
|
Observations
|
Catch |
|
|
0' |
0' |
N |
W (kgs) |
||||
|
5/3 |
0200 |
13 05 |
90 42 |
>500m |
Few small |
0 |
|
|
5/3 |
0410 |
13 18 |
90 38 |
>500m |
Few small/med. |
0 |
|
|
5/3 |
0500 |
13 26 |
90 36 |
650m |
Negative |
0 |
|
|
6/3 |
0100 |
13 10 |
91 00 |
>500m |
A few specim. |
2 |
0.72 |
|
6/3 |
0240 |
13 00 |
91 08 |
>500m |
A few specim. |
7 |
1.55 |
|
6/3 |
0430 |
13 12 |
91 11 |
>500m |
Small and med. |
5 |
2.41 |
|
7/3 |
0150 |
13 41 |
92 07 |
>500m |
A few |
0 |
|
|
7/3 |
0350 |
13 39 |
92 23 |
>500m |
Negative |
0 |
|
|
8/3 |
0210 |
14 06 |
92 33 |
300m |
Negative |
|
|
|
8/3 |
0330 |
14 05 |
92 41 |
>500m |
Some spec, |
1 |
|
The fishing stations worked in Mexican waters are listed in Annex 2 stations no 189 through 223. Most of the hauls are from the areas of inshore fish distribution, see Figures 1 and 4. The majority of these hauls are made at prelocated positions, but the catch rates were still relatively high. Up along the coast to about Barra de Tonala', the entrance to the Mar Muerto, the catches estimated in rates per hours tow ranged from 75 to 770 kgs with a mean of 360 kgs. Carangids and sardines dominated the catches. In two pelagic hauls (nos 201 and 206) the rates were 660 and 1100, carangids, sardine and barracuda. Further westwards the rates were considerably higher with 5 out of 9 hauls exceeding 1.8 tons and a mean of nearly 1.5 tons. The composition was here different with butterfish and grunts dominating with some carangids, round scad and bumper, but few sardine. Small quantities of shallow water penaeid shrimp appeared in some of the hauls along the whole coastline.
Off Salina Cruz shelf squid (Loliolopsis) of good size was caught with rates of 60 - 120 kgs per hour (st 221 and 222).
Table 3 shows the records of the offshore trawling for langostino. A few good caches were made in the southeast, but sizes were small and the programme was not continued westwards as the indications were poor for this species. Some trials were however, made for crystal shrimp (Penaeus brevirostris) in the 50 - 70 m depth range of the north western part of the Gulf, see Table 3. This species seems to be widely distributed and the sizes encountered were fair. Daylight fishing gave insignificant catches in relation to night fishing as shown by comparing st 212 and 218 from the same position.
Table 3. Catches of langostino and crystal shrimp, Golfo de Tehuantepec, Mexico. (D - day, N - night).
|
Station |
Depth |
Langostino |
Shrimp |
||
|
no |
m |
tons/hour |
mean weight |
kgs/hr |
mean weight |
|
189 |
200 |
6.2 |
6 grms |
|
|
|
194 |
190 |
0.36 |
6 grms |
|
|
|
195 |
310 |
- |
|
|
|
|
196 |
160 |
1.1 |
5 grms |
|
|
|
202 |
210 |
- |
|
|
|
|
203 D |
70 |
|
|
3 |
12 gr |
|
207 N |
60 |
|
|
19 |
13 gr |
|
208 N |
61 |
|
|
18 |
18 gr |
|
212 D |
59 |
|
|
2 |
16 gr |
|
216 N |
56 |
|
|
19 |
23 gr |
|
217 N |
57 |
|
|
56 |
14 gr |
|
218 N |
60 |
|
|
37 |
10 gr |
Table 4. Testing for oceanic squid (Dosidiscus gigas) with light and jigging, Golfo de Tehuantepec, Mexico.
|
Date
|
Hour
|
Latit. |
Longi. |
Depth
|
Observations
|
Catch |
|
|
0' |
0' |
N |
W (kgs) |
||||
|
8/3 |
0430 |
14 11 |
92 42 |
>500m |
A few |
0 |
|
|
9/3 |
0210 |
14 25 |
93 08 |
440m |
Some small sp. |
0 |
|
|
9/3 |
0400 |
14 32 |
93 20 |
390m |
Some small sp. |
|
|
|
9/3 |
0500 |
14 36 |
93 26 |
450m |
Negative |
0 |
|
|
10/3 |
0410 |
14 35 |
94 04 |
290m |
Negative |
0 |
|
|
10/3 |
0540 |
14 44 |
94 10 |
>500m |
Negative |
0 |
|
|
11/3 |
0140 |
15 40 |
94 32 |
240m |
Negative |
0 |
|
