Innsig av akkar, Todarodes sagittatus (Lamarck), til norskekysten høsten 1977 - våren 1978

After 1971 the squid T. sagittatus did not return to Norwegian coastal waters until the autumn of 1977. In August it was observed near Bergen and Cape Stad farther north, and in September in Vesterålen, North Norway. The fishery started in October in North Norway, lasting till November; near Cape Stad it lasted until the middle of March 1978. The fishery yielded about 200 tonnes. Single squid were still being caught in July. Material for investigation was collected from the fishery and during research cruises (Table 1). Results from earlier investigations (WIBORG 1972) were confirmed. The mean mantle length increased from 28 cm in October to 39 cm in March, the mean weight from 400 g to 1500 g in the same period. The liver weight was usually 10-1470 of the total weight, decreasing during winter. Near Cape Stad the squid had a higher weight percentage of liver, maximum 22, with averages of 14-15 in October, decreasing to 10-12 in January - March. The males constituted about 12-14% of the stock off North Norway in October, decreasing to 7-9% in November. Farther south, males were scarce, in some samples entirely absent. All squid were immature, but a female caught in May had nidamental glands 13 cm long, and eggs in the ovary were 1.2 - 1.5 mm in diameter, corresponding to developmental stage III (of four). The same food items were identified in the stomachs as earlier. Fish dominated, mostly herring and saithe, but squid were also usual. The shrimp (Crangon almanni) was very common in the stomachs during winter near Cape Stad. The degree of filling was as a rule low, but near Cape Stad nearly 30% of the stomachs were full or distended in October, making up to 17% of the total weight. Information on the occurrence of T. sagittatus in other areas is still scarce. None or very few are taken during the squid fisheries near Ireland and Spain. A few have been caught with pelagic trawls in the Bay of Biscay. Introduction of T. sagittatus as food and snacks on the Norwegian market has met with success. The consistency and taste is similar to that of other recognized species of squid. Experiments have shown that the meat may be deep-frozen, thawed and frozen again without reduction of the quality, and may also be used for a great variety of products and dishes. The fishery and fishing methods in Norway are still little developed. Use of sonar to locate the squid is suggested, and purse seining or use of a fish pump could supplement improved methods of jigging

Investigations on Zooplankton in Coastal and Offshore Waters of Western and Northwestern Norway - With Special Reference to the Copepods

1. Zooplankton samples, taken in vertical Nansen net hauls at permanent stations on the west coast of Norway between 61°-63° N and in the Lofoten area from October 1948 to the end of December 1951 have been used for a complete analysis of the variation in volume, plankton composition and biology of the species. A study has also been made of the variations in plankton volume of selected samples collected in the same area during 1927-39 and 1946-48 with the same gear, and during 1949-51 with Clarke- Bumpus plankton samplers. Plankton material from station "M" in the Norwegian Sea, taken in vertical Nansen net hauls in steps from 2 000 m to the surface during 1950-52 has been used for studies of variations in plankton volume and of variations in length of the copepods. 2. Volume measurements were made by draining or displacement, subdivisions of the samples by the improved Lea's plankton divider. All plankton has been preserved in formalin. 3. The hydrographical conditions of the investigated areas are discussed on the basis of previous investigations, and of observations taken simultaneously with the sampling of plankton. At the coastal localities more or less continuous changes take place in the body of water due to the influence of the Baltic current and the North-Atlantic current. At Skrova in the Vestfjord the conditions seem to be more stable. A survey of the more important changes during 1949-51 is given in table 1, pp. 20-21. 4. a. On the west coast of Norway between 61°-63° N the maxima in the volume of plankton usually occur in April and June-July, in the Lofoten area in May-June and July-August. The main quantity of plankton is found in the upper 50 m from April to July, with maximum in June. Generally, the plankton was most abundant in the Lofoten area, and in all localities there was also an increase in the yearly mean volumes from 1919 to 1951. b. Plankton samples taken in earlier years show volume variations siislilar to those recorded in the present investigation. c. The quantitative distribution of plankton in the Lofoten and Vesterålen area in April-June of the years 1949-51 based on samples taken with Clarke-Bumpus plankton samplers is shown. Surface currents seem to be of great importance for the distribution, while diurnal vertical migrations of the plankton organisms have no influence, the plankton in spring being concentrated in the upper 75 m. There is, on the average, quite good agreement between the quantities of plankton calculated per m² of sea surface from the hauls with the C. B. sampler and with the Nansen net. d. At station "M" in the Norwegian Sea there was a maximum of plankton volume in the upper 100 m in June, minimum in the period September-March. The plankton was more abundant in 1950 than in 1951, the temperature of the surface layers being on an average somewhat lower in 1951. - The volumes mere generally larger than in the upper 50 m on the west coast of Norway between 61°-63° N, but smaller than in the same layer in the Lofoten area. e. A comparison is made between the quantities of plankton in various European and American waters. During spring and summer the bank water off Eggum is comparable in richness to the waters of Georges Bank off the east coast of U.S.A., and to those in the Barents Sea. The greatest concentrations of plankton hitherto recorded in Northern waters, are found in summer ancl autumn in the Barents Sea. 5. There are two periods of abundance in the total number of organisms, at Sognesjøen and Ona in March-July and August-September, in the Lofoten area in April-May and August-October. Numbers are generally higher in the Lofoten area, and were on the whole greater in 1950 than in 1949. The copepods always dominate, but cladocera, eggs and larvae of euphausiids, bottom invertebrate larvae, copelata, and some other groups may at times be of some importance. 6. The variations in the relative composition of the copepod stock are shown both as to number and volume. More than 38 species have been identified, of which only 4 are of any importance in number all the year, viz. Calanus finmarchicus, Pseudocalanus elongatus, Microcalanus pusillus and Oithona similis. Sometimes, especially in the autunm, Metridia lucens, Paracalanus parvus, Temora longicornis and Acartia clausi may also play a certain part. - In volume C. finmarchicus is always dominant but at Skrova C. hyperboreus and Pareuchaeta norvegica may also be of some importance. 7. The plankton organisms have been divided into different groups according to their origin and appearance in the plankton, and the renewal of the stocks is discussed. Organisms indicating influx of Atlantic water are listed. 8. Length distributions of copepods are shown to be useful for the determination of the origin of the populations and also for the determination of the origin and degree of mixing of different water masses. 9. The production of zooplankton in Norwegian coast waters is discussed in relation to the production of phytoplankton, likewise the greater abundance of zooplankton in spring near the edge of the continental shelf and the possible origin of the plankton populations there. The importance of the statement by MARSHALL and ORR (1952), that individual females of Calanus finmarchicus may survive and produce eggs for more than two months, is stressed. 10. The biology of the different species. a. Calanus finmarchicus. At Sognesjøen and Ona maxima in stock occur in March, June-July and September, at Eggum and Skrova in April-May and August. Spawning periods at Sognesjøen and Ona in February-March, Nay-June, July-August, and September- October, in the Lofoten area in April-May, June, and July-September. Copepodite stage V had a minimum length in February-March, maximum length in April-July, and was again smaller during the autumn. The females showed a similar variation. At Skrova there was a very striking decrease in mean length of stage V from January to March each year. - At station "M" the length variations of stage V in the upper 100 m during the late summer and autumn of 1940 was very similar to that found at Eggum, and the possible relationship is discussed. b. Calanus hyperboreus was scarce at all stations except Skrova, where a moderate stock occurs in the deeper layers all the year. Spawning takes place in February. Stage V and the females vary very little in length distribution during the year. c. Pseudocalanus elongatus had maxima in stock in May-June and August-September, at Eggum also in October-November. Maxima in spawning at Sognesjøen and Ona occurred in March, May-June, August and October, at Eggum in March-April, May-June and September. The females showed a minimum mean length in January- March, maximum length in April, and decreased again in length from the end of April. d. Pseudocalanus minutus (P. gracilis G.O. Sars) was shown to be distinct from P. elongatus. Scarce at all stations, being confined mainly to the deeper layers. Spawning probably occurs in March-April. Stage V and the females were larger than P. elongatus from the same samples. The dominance of P. minutus at station "M" is confirmed and discussed. e. Microcalanus pusillus occurred in moderate numbers with 3 or more maxima in stock and 4-5 spawning periods a year. The females had maximum size at Ona in May and October, minimum size in February -March and August. At Eggum and Skrova there was maximum length in May only. The length variations at station "M" were similar to those at Ona. The relation length-temperature is discussed. f. Microcalanus pygmaeus is shown to differ from M. pusillus both in size and in appearance. It is scarce at Skrova, but present all the year, with one spawning period a year, in February. The individuals found in deep water at station "M" are larger than those at Skrova. g. Pareuchaeta norvegica. Found in moderate numbers in deep water at Skrova. Spawning takes place all the year, with maximum in December-January and June-August. Females are more than twice as numerous as the males, but in the copepodite stage IV-V the proportion was 1:1. The mean length of stage V decreased slightly from the spring to the autumn. 11. Metridia lucens is an important component of the summer plankton, with maxima in stock in June-October. Four to five spawning periods occur. Nauplii are most common in the upper 50 m, but as development proceeds, the copepodites seek deeper water, and of the adults only 5-9 % are found in the upper 50 m. The mean length of the females showed minimum in January-February, maximum in May, and decreased again gradually during the autumn. i. Clausocalanus arcuicornis is new to the Norwegian fauna, occurring sparsely from October to January. k. Oithona similis was sometimes very abundant, with main maxima in August-September. The other copepod species are of less importance numerically. 11. Other organisms. a. Cladocera were present from March to October, most abundant in June-September. b. Adult euphausiids were seldom taken. Eggs and larvae of euphausiids were numerous from March to June with maxima at Sognesjøen and Ona at the end of March (both Meganyctiphanes norvegica and Thysanoessa inermis), in Lofoten in April and May (mainly T. inermis). c. Chaetognaths were most common on the cleeper stations, especially at Skrova. Sagitta elegans and Eukrohnia hamata were the most commonly found species, but single S. setosa occurred at Sognesjøen and Ona. d. Copelata. Oikopleura dioica was most abundant at Sognesjøen and Ona, O. labradoriensis in the Lofoten area. O. vanhøffeni occurred in moderate numbers at Eggum, singly at Ona and Skrova. Fritillaria borealis acuta was moderately numerous, but scarce at Ona. e. Thaliacea. Salpa fusiformis was recorded in the autumn of 1950 at Ona, Eggum and station "M" in 1951 at, Sognesjøen and Ona. f. Limacina retroversa was numerous at all stations except Skrova from June-July to October. g. Herring larvae were numerous at Sognesjøen and Ona in March, cod eggs and larvae plentiful in the Lofoten area in April-May, especially in 1949. The other groups of organisms, amphipods and isopods, ostracods, gasteropod larvae, larvae of bottom invertebrates, coelenterates and others, were usually of minor importance numerically

(Gonatus fabricii (Lichtenstein)). Investigations in the Norwegian Sea and the western Barents Sea, February-September 1980 and July-September 1981

Investigations on Gonatus fabricii (gonatus) continued during 1980 and 1981. Material was collected with pelagic and bottom trawls during postlarval and 0-group fish surveys. The geographical and quantitative distribution of juveniles was very similar to that found in 1978-1979, but gonatus was more scarce off northwestern Norway in July 1981 than in June-July 1980. In July 1980 gonatus was very numerous west of Jan Mayen, maximum 8000 specimens per half hour's hau1 with Harstad trawl, 18 m x 18 m opening. In April 1980 small gonatus, mostly with 10-24 mm dorsal mantle length, (DML) were taken off western Norway. Small specimens were also found in the central Norwegian Sea in August 1980. During June- July 1980 DML were 5-60 mm, a few up to 84 mm. West of Jan Mayen gonatus in July 1980 ranged from 30 mm to 80 mm, mostly 35-64 mm. In the Norwegian Sea there were peaks at 15-24 mm and 50-60 mm whereas only small gonatus, 10-34 mm, were taken in the upper 50 m in July 1981. Larger gonatus, DML 126-250 mm, were only taken in deeper layers (400-550 m) or in bottom trawl hauls near Jan Mayen. Stomach contents of juvenile gonatus were dominated by amphipods, mainly Parathemisto sp. Copepods, chaetognaths, krill and Sebastes larvae were also identified. Larger gonatus had eaten Maurolicus muelleri and small gonatus. The study of growth rings in the statoliths has been continued using a microscope with 1000 x enlargement. Earlier countings have been revised. Near Jan Mayen, gonatus with DML 35-77 mm had 204-380 growth rings, but no correlation was observed between lengths and number of rings. In the Norwegian Sea, gonatus with DML 14-24 mm had 100-116 rings, DML 30-72 mm 172-229 rings, and 159-250 mm 287-330 rings. If the rings represent days, the largest specimens are less than one year old. As gonatus grow larger, they leave the upper water layers, and those with the highest growth potential may leave first. They probably also change their feeding habits to larger and more nutritious organisms such as fish and squid. More data on age and growth, especially from larger gonatus, are needed to get reliable information

(Gonatus fabricii (Lichtenstein))En mulig fiskeriressurs i norskehavet

Gonatus fabricii (hereafter gonatus) is a pelagic squid, widely distributed in boreal and subarctic waters. Material for the present investigation has been collected since 1970 mainly in the Norwegian Sea and adjacent areas during postlarval and 0-group fish surveys during late summer and autumn. Earlier material used included stomach contents from hooded seals caught in the Jan Mayen area, and from bottlenose whales taken east of Iceland and off Labrador. Gonatus larvae were also taken in plankton net hauls at Station M at 66°00'N 02°00'E. Gonatus with mantle lengths 6-20 mm were found in the Norwegian Sea between December and July, 25-45 mm in February - September, and 55- 100 mm in May - September and in December. Larger squid, mantle lengths 13-28 cm, were only taken from stomach contents of hooded seals and bottlenose whales. During 1978 gonatus with mantle lengths 15-45 mm were very abundant in the surface layers of the central and eastern Norwegian Sea during summer and autumn, up to 2000 specimens (5000 ml) were taken in half hour hauls with a Harstad trawl, 18 x 18 m opening. Juveniles also became stranded along the coast of eastern Finnmark in North Norway during the autumn. The correlation between rostral length (RL)of the beak and mantle length of gonatus has been roughly calculated. In stomach contents of bottlenose whales caught off Labrador during May - June 1967, the calculated mantle lengths of gonatus varied from 6 cm to 30 cm, mostly 13-28 cm. In the Norwegian Sea spawning and hatching of gonatus probably occur from December to July, with the peak in April - June. The main areas of spawning may coincide with localities where bottlenose whales are abundant as can be seen from catch statistics, e.q. off eastern Iceland, Møre, Vesterålen and West of Spitsbergen (Fig. 7). The life cycle of gonatus is probably closely connected to the current system of the Norwegian Sea and adjacent seas. A fishery for juvenile gonatus should be tried in these areas, chiefly during April - August, using trawls, lights and dip nets or pumps; for larger squid, jigging gear combined with lights should be used

Forekomst av egg og yngel i nordnorske kyst- og bankfarvann våren 1950 og 1951. Foreløpig beretning II.

Særtrykk av «Fiskets Gang» nr. 4 - 195

(Gonatus fabricii (Lichtenstein)). Investigations in the Norwegian Sea and the western Barents Sea, June-September 1979.

Investigations on Gonatus fabricii (gonatus) continued in 1979. Material was collected during postlarval and 0-group fish surveys. The distribution of gonatus was very similar to that found in 1978. During June-July, small gonatus were abundant in the northeastern Norwegian Sea, maximum 4000 specimens in half hours' hauls with a Harstad trawl, 18 x 18 m opening. Recordings with a Simrad EK-120 echo sounder and integrator showed highest intensity in the area of maximum catches. In June-July mantle lengths were mostly 5-50 mm, maximum at 15-19 mm with average length 28 mm, but a few larger individuals, up to 80-84 mm, were found. Preliminary countings of growth rings in the statoliths indicated an age of 30 days for gonatus with mantle length 15 mm, 45 days for lengths of 25-35 mm, 65-75 days for lengths of 40 mm and 80 days for 50 mm. The results are given with reservation. Stomach contents were dominated by amphipods, copepods and chaetognaths. Other organisms identified were euphausiids, pteropods, mussel larvae, fry of Sebastes and tentacles of gonatus