ISSN 0704-3716

Canadian Translation of and Aquatic Sciences

r- No. 5621

Results of exploratory in the Northwest Atlantic

L.N.Pechenik

Original title: Rezul'taty poiskovykh rabot v severo-zapadnoi Atlantike

In: Not available 1 Department of Fisheries & Oceans _ tii'.\et 28 1994 1 language: Russian Original 1 Ministère des Pèches et des Oceans , OTTAWA

Available from: Canada Institute for Scientific and Technical Information National Research Council Ottawa, Ontario, Canada KlA 052

1994

6 typescript pages Government of Canada - Gouvernement du Canada

MULTILINGUAL TRANSLATION DIRECTION DE LA TRADUCTION DIRECTORATE MULTILINGUE

TRANSLATION BUREAU BUREAU DE LA TRADUCTION

Department/Ministère Branch/Direction Division City/Ville D F 0 INI&TS Ottawa

Bureau No./N° du Bureau Uanguage/Langue Translator/Traducteur Date 2792078 Russian N. De.

[Source not available], pp. 26-29

UDC 639.208.17

Results of exploratory fishing in the Northwest Atlantic

by L.N. Pechenik, head of the Northern Fishing Survey [Office]

During the spring—summer of 1964, the Northern Fishing Survey [Office] dispatched three scouting trawlers to survey the continental slope of some of the regions of the NW Atlantic (fig. 1). A total of 274 deepwater trawlings were carried out. The Western Greenland shelf is known as one of the most complex regions of the world's oceans as regards bottom conditions. The fish searches carried out by the large freezing stern-trawler "Mayakovsky" in the zone of the continental slope con- firmed the fact that the conditions for work with a trawl were extremely unfavorable here (rocky bottom, rugged bottom relief). The fish-scouting vessels for surveying the continental slope were equipped with the standard bottom trawl made of capron [nylon-6] (large freezing stern- trawler "Mayakovsky" - 31.2 m, large side-trawler "Pobeda" - 31.4 m, large side- trawler "Zapad" - 25 m). Before beginning the scouting operations on the "Pobeda", the optimal parameters of the trawl were determined; a speed of 3.8-4.2 knots provided better fishing spread and height of the trawl (a speed of 3.8-3.9 knots was maintained in the majority of cases). The warps scope was equal to 2.5-3 depths, and the length of the cables to 80 m. The ground rope was rigged in accordance with the requirements for commercial vessels. At higher trawling speeds, a weight of 60 kg (chains) was added. The headline was rigged with 82-85 floats, and another 16-18 floats were attached to the codend. 2

Special deepwater metal floats with 2.5 mm walls were used. They were tested beforehand in a decompression chamber at 80 atm; not more than 3-4 of these floats underwent deformation at depths of 800-850 m. 500 mm bobbins with 10 mm walls also proved to have good pressure resistance. Oval and rectangular weighted (1300 kg) trawl-boards were used. Trawling time averaged 1.5 hours. After shooting the trawl, we allowed 5-6 minutes for it to settle on the bottom. The Soviet-made "Kalmar" recorded fish aggregation up to 700 m, and the German "Lodar" registered fish aggregation up to 500 m. When working at greater depths, exact positioning of the vessel is extremely important. As the operations on the "Mayakovsky" have shown, the possibility of determining at any moment the location [of the fish aggregation] with the help of a remote radionavigation device and staying on the school of fish increases fishing efficiency. The bulk of the catches in this area consisted of roughhead grenadier; one brief haul of a trawl yielded up to half a ton of this fish. The deepwater fishes Alepocephalus boirdi (Fig. 2) and Hoplostethus islandicus (Fig. 3)*, caught by the "Mayakovsky" off the coast of Western Greenland, are of scientific and commercial interest to us. The first species belongs to the Clupeidae, and the second to the Berycidae. Both species were caught with a trawl in the vici- nity of Frederikshaab bank. Alepocephalus boirdi was caught at a depth of 640-650 m, and 30 minutes of trawling yielded 0.3 tons of this fish; the fish measured up to 90 cm, and the females were just about to spawn. These results suggest that this species forms dense concentrations during the spawning period. Hoplostethus islandicus, previously unknown in the waters of Western Greenland, was caught at a depth of 620-680 m; tens of these fish were caught with the trawlnet. The biology of these two species and their distribution in the world's oceans are as yet unknown. A preliminary biochemical analysis carried out by PINRO has shown that the taste qualities and calorie content of Alepocephalus biordi are similar to that of , and Hoplostethus islandicus is similar to ocean perch.

* Species identified by A.I. Postolaky, a researcher with PINRO [Polar Research and Projecting Institute of Marine Fisheries and Oceanography] 3

Fig. 1. Survey map of the continental slope in some areas of the NW Atlantic

The bottom conditions at greater depths off the coast of S Labrador south of 540 N lat are, on the whole, satisfactory, despite the presence of muddy patches and underwater obstacles upon which trawl gear may get entangled. North of this parallel, the bottom relief is highly irregular, and trawlnets are often damaged. On the continental slope in the vicinity of the Grand Banks of Newfoundland, the conditions for trawling are the most difficult. However, there are many areas that are convenient for trawling operations along the entire Labrador- Newfoundland slope. The species composition of the catches varied with the depth of trawling. Cod predominated in the catches up to 300 m, and 35-45 cm deepwater redfish (Sebastes men tella Travin) formed the bulk of the catches at greater depths. The incidental 4 catch varied not only with depth, but with the fishing area as well. For instance, in the vicinity of S Labrador, the bonus catch of Greenland halibut did not exceed 10% of the take; however, its quantity in the catches increased as the operations moved southward. On the northern Grand Banks, there was significantly more of this species than in other areas; some of the hauls consisted 45-70% of halibut. The highest concentrations of Greenland halibut were found at depths of 650-700 m. The bonus catch of righteye flounders was also quite high here. The roughhead grenadier was encountered everywhere at great depths, but commercial accumulations of this species were not observed during this period.

Fig. 2. Alepocephalus boirdi

Fig. 3. Hoplostethus islandicus

On the northern Grand Banks, the northeastern slope and the Flemish Cap bank, the most productive depths from May to July were in the 500-700 m range where the highest concentrations of deepwater redfish were observed. Fishing success diminished at depths greater than 700 m. The catches from one and a half hours of trawling at depths of 500-700 m with a side-trawler frequently yielded 5 tons of redfish. Deep-sea fishing on the northern Grand Banks and the Flemish Cap bank was particularly productive. For instance, on the first of these banks, the daily average catch of redfish by the "Pobeda" side-trawler at depths of 630-700 m from June 16-20th amounted to 16.5 tons, and on some days as much as 27 tons. Similar 5 results were obtained by the "Zapad" side-trawler on the Flemish Cap bank where the catch of redfish at depths of 550-650 m at times reached 20 tons. In the vicinity of S Labrador, the deepwater redfish was distributed uniformly at depths of 450-650 m, without forming dense concentrations. On the southwestern slope of the Grand Banks, the 400-450 m interval proved to be the most abundant in fish. The redfish here is smaller than in the northern areas, and perhaps this„species forms especially dense concentrations in shallower areas. PINRO's detailed analysis and study of the biological indices of the deepwater redfish caught at depths greater than 500 m have shown that this species, which is similar in appearance to the redfish caught at smaller depths, differs greatly from the latter in a number of biological characters. With a few exceptions, the redfish was immature (1st stage), the males and females did not differ in size as in mature redfish, and there was hardly any difference in the growth rate of the males and females (Sidorenko, Savvatimsky, 1965)- On the basis of all of these factors, the authors have concluded that the deep- water redfish represents a group that is different from the redfish found at smaller depths (200-500 m). Our results indicate that the opening up of resources and the organization of fishing operations at deeper levels of the ocean is one of the major ways of increasing the landings of fish..Each vessels should already be equipped with deepwater gear (floats, bobbins, weighted boards) for fishing at greater depths.