Argentina Silus Research Articles

Greater silver smelt, Argentina silus in Icelandic waters

This paper presents results obtained from data on the greater silver smelt Argentina silus in Icelandic waters collected by the Marine Research Institute, Iceland, mainly since 1981. The greater silver smelt is most abundant in the waters off the south‐east coast of Iceland clockwise to those off the west coast, but the species has also been observed off the north coast. Differences in the size composition in relation to area and depth are described. The preferred depth range of the greater silver smelt was found to be 300‐600 m and the preferred temperature was about 6°C. Ageing is described showing a relatively fast growth up to the age of 8‐9 years. The age/length and length/weight relations are given. Females grow faster than males. The 50% maturity point is reached by males at a length of 36‐37 cm and at an age of approximately 8 years, and by females at a length of 37‐38 cm and approximately 9 years. Spawning takes place to some extent year round but with one or two periods of greater intensity. Results from experimental fishing are described and problems in connection with a Commercial fishery are discussed.

Morphometry of Atlantic argentine Argentina silus (Ascanius, 1775) (fam. Argentinidae, Salmoniformes) from the northeast Atlantic

Morphometry of Atlantic argentine Argentina silus (Ascanius, 1775) (fam. Argentinidae, Salmoniformes) from the northeast Atlantic

Deep-water ichthyoplankton of the Skagerrak with special reference toCoryphaenoides rupestrisGunnerus, 1765 (Pisces, Macrouridae) andArgentina silus(Ascanius, 1775) (Pisces, Argentinidae)

Abstract Two species, Coryphaenoides rupestris and Argentina silus, were abundant in the ichthyoplankton of the 150–550 m depth zone of the Skagerrak in 1992. Eggs of C. rupestris occurred only in October and December and a single yolk sac larva was caught in December. Postlarvae and juveniles occurred in all months (Feb, Apr, Jun, Oct, Dec) and showed a continuous increase in length through the year. This confirms earlier indications of a single late autumn spawning period. By October the juveniles had attained a demersal mode of life. Argentina silus eggs and larvae occurred year-round, but eggs were most abundant in the spring. Most of the other fish eggs and larvae were probably caught incidentally in surface layers. Exceptions may be four postlarval Atlantic halibut Hippoglossus hippoglossus L.

Distribution, population structure, growth, and reproduction of the greater silver smelt, Argentina silus (Pisces, Argentinidae), of the Skagerrak and the north-eastern North Sea

Distribution, population structure, growth, and reproduction of the greater silver smelt, Argentina silus (Pisces, Argentinidae), of the Skagerrak and the north-eastern North Sea

Ecology of the fishes of the Norwegian Deep: Distribution and species assemblages

An account based on hydroacoustic data and trawl surveys of the distributional patterns and species assemblages of the fishes inhabiting the Norwegian Deep and adjacent slopes is presented. The Norwegian Deep is the moderately deep (275 to 700 m) shelf channel extending from the Norwegian Sea into the North Sea and Skagerrak. The Norwegian Deep has a pelagic and demersal fish fauna which is rather different from the fauna in adjacent shallow areas. Blue whiting ( Micromesistius poutassou) and Maurolicu muelleri form a widely distributed and normally two-layered pelagic association. There appears to exist a rather sharp boundary at about the 200 m isobath between species assemblages of the Norwegian Deep and those of the shallow plateaus of the North Sea and Skagerrak. The fish fauna of deeper zones of the Skagerrak differs from the areas off western and southwestern Norway. The more conspicuous feature in the Skagerrak is the rather high abundance of greater argentine ( Argentina silus) and roundnose grenadier ( Coryphaenoides rupestris) at depths greater than 300 m. The species assemblages of the Norwegian Deep resemble those found in the areas along the outer shelf of the Northeast Atlantic and the deep fjords of Norway. The western and southern slopes appear to be feeding and overwintering areas for some fish species from adjacent shallow areas, particularly populations of saithe ( Pollachius virens) and Norway pout ( Trisopterus esmarki). It is suggested that the Norwegian Deep, due to its characteristic bathymetry and the strong influence of Atlantic inflow, is colonized by mesopelagic and benthic species from the other shelf areas of the Northeast Atlantic. The shelf channel appears to be deep enough to allow outer shelf species temporary or permanent access to the inner shelf environment.

Size and age at sexual maturity of Atlantic argentine,Argentina silus: a critique

A recent analysis of size and age at sexual maturity ofArgentina silus on the Scotian Shelf is invalid because field maturity stage data collected during the non-spawning, quiescent stage of the reproductive cycle were unreliable for distinguishing between immature and resting mature stages. Thus two-thirds of the data used must be discounted. Utilization of different length measurement criteria for different years, for which no correction is made, could introduce substantial error in length at maturity estimates based on the remaining data. Age data collections were restricted to one 12 month period and thus were inadequate to characterize age at maturity by 5 yr time periods as attempted in this analysis. No attempt is made in the analysis to determine whether available samples adequately represent the population with regard to maturity i.e. whether immature and mature fish of the same length had an equal probability of being sampled. It is demonstrated here that maturity ogives can differ greatly depending on assumptions made concerning the representativeness of samples. Many of the criticisms made are likely valid for a series of papers on maturity of Atlantic coast fishes by the same author.

Variation in length and age at sexual maturity of Atlantic groundfish: a reply

The assertion has been made by Halliday (1987) that trends in size and age at maturity of Atlantic groundfish published by Beacham (1983a, b, c, d, e, f) are artifacts induced by errors in determining the sex of an individual, distinguishing between immature and mature fish, sampling fish outside of the regular spawning season, and by nonrandom sampling of the population. In particular, Halliday asserts that for the Atlantic argentine,Argentina silus analysis, the conclusions of Beacham (1983a) that: (1) median length at sexual maturity declined over time; and (2) males matured at older ages than did females are invalid owing to biases in both sampling and analysis. In fact, if some of the biases indicated by Halliday were significant, then the decline in median length at sexual maturity is enhanced and the conclusions of Beacham (1983a) reinforced. Size and age at sexual maturity are dynamic characters in many vertebrate populations, and the fact that they should change for Atlantic groundfish should not be surprising given variable exploitation patterns in the fisheries since 1960.

Squid as feed for salmonids

The populations of squid and cuttlefish in the oceans are an enormous source of protein. Only 500 000 metric tons, which may be only 0.5% of the potential catch, is harvested annually. Not only offal from processing of squid but also species and catches not destined for human consumption are potential sources of protein in aquaculture. Flying squid ( Todarodes sagittatus Lamarck), stored frozen, was tested in moist diets for rainbow trout ( Salmo gairdneri Richardson) and salmon ( Salmo salar L.). In the test diets, the three squid parts — mantles, whole bodies, and tentacles, heads and guts — each replaced argentine ( Argentina silus Ascanius) which was used in the control diet. On a wet weight basis the diets contained about 46% squid. The diets were approximately isoenergetic and had the same protein: fat ratio. The presence of squid in the diet resulted in greater increases in weight and length, a higher condition factor, no change in carcass percentage and higher dry matter and fat contents in both rainbow trout and salmon than with the control diet. There were no significant differences in these production traits between the fish that received the three different squid parts.

Dogfish offal, ensiled or frozen, as feed for salmonids

An underutilized feed source, offal from filleting of picked dogfish ( Squalus acanthias, L.), was tested as a source of protein in moist diets for salmon ( Salmo salar, L.) and rainbow trout ( Salmo gairdneri, Richardson). The offal was divided into two lots; one was preserved by freezing and the other by the addition of formic acid, 2.5% (w/w). Two experimental diets were tested in which either frozen or ensiled dogfish replaced an industrial fishery catch, consisting mainly of argentine ( Argentina silus, Ascanius), which was the wet component in the control diet. In both experimental diets, 47% of the wet weight, or 30% of the total N, was supplied by dogfish. No negative effects were observed in feed consistency or in the fish's weight increase, health, chemical composition or organoleptic properties in any of the groups. The apparent digestibility of the dogfish protein was as high as that of the protein from argentine and of the binder meal, and it was highest for dogfish preserved by formic acid. Of the total N, 20–30% is urea N and must be subtracted when comparing the protein value of the dogfish offal with other filleting offals.

Variability in size and age at sexual maturity of argentine, Argentina silus, on the Scotian Shelf in the Northwest Atlantic Ocean

The variability in the length and age at which 50% of individuals were mature was investigated for argentine (Argentina silus) in the Northwest Atlantic. Median length at maturity generally declined with time, the trend more pronounced in females than in males. Males and females matured at similar lengths, but males tended to mature at older ages. From 1965–1969, median length at maturity for males ranged from 35.4 cm in NAFO Subdiv. 4Vs to 26.4 cm in Div. 4W, while that for females ranged from 28.0 cm in Subdiv. 4Vs to 24.9 in Subdiv. 5Ze. From 1965–1969, median age at maturity was about 5.3 yr for males and 4.6 yr for females.

Stability of the Minced Flesh of Argentine (Argentina silus) and Roundnose Grenadier (Coryphœnoides rupestris) During Storage at —10°C

Stability of the Minced Flesh of Argentine (Argentina silus) and Roundnose Grenadier (Coryphœnoides rupestris) During Storage at —10°C

Nutrient Composition of Experimentally Produced Meals from Whole Argentine, Capelin, Sand Lance, and from Flounder and Redfish Filleting Scrap

Nutrient composition studies have been carried out on single samples of meals produced from whole Atlantic argentines (Argentina silus), capelin (Mallotus villosus), American sand lance (Ammodytes americanus) and from filleting scrap from flounders (Pleuronectidae sp.) and redfish (Sebastes marinus).Analyses included protein, fat, ash, moisture, minerals, vitamins, available lysine, amino acids, and protein digestibility. The whole fish meals appeared nutritionally equal to good herring meal. The filleting scrap meals were lower in protein content but the nutritional values of the proteins were equivalent to that of herring.

The gas bladder of Argentina silus L., with special reference to the ultrastructure of the gas gland cells and the countercurrent vascular bundles.

The orifice between the two chambers of the gas bladder in Argentina silus is surrounded by a sphincter muscle. Gas analyses of the gas bladder contents of fish from 400 meters depth give 0–1% carbon dioxide and 9–72% oxygen. Micro-retia mirabilia form a countercurrent vascular system, and the arterial component has peripherally a sphincter mechanism. The function of the “glandular layer” of the anterior chamber remains uncertain, but the structure indicates secretion into blood capillaries. The lining epithelium of the anterior chamber may secrete some substance into blood or directly into the lumen, which may be involved in a secretory mechanism. This conclusion is not supported by our histochemical tests. The posterior chamber has no micro-retia and the blood vessels have a different origin from those of the anterior chamber. The blood vessels form a plexus of capillaries or sinuses in contact with the flat lining epithelium, thus allowing gases to pass freely by diffusion. — The muscular layers of both chambers are innervated by catecholamine-containing nerve fibres.

Trematode Populations in the Atlantic Argentine, Argentina silus, and Their Use as Biological Indicators

The trematode parasites Lecithophyllum botryophorum, Derogenes various, Hemiurus levinseni, and Lampritrema nipponicum were found in Argentina silus off Nova Scotia and Newfoundland. Changes in the length-frequency distribution in the population of L. botryophorum at different times of the year reflected changes in parasite recruitment and were used tentatively to estimate the life span of the parasite.Hemiurus levinseni had a high intensity and incidence in very young fish, decreasing to a low level in mature fish; L. botryophorum had the reciprocal relationship; and D. varicus was intermediate in incidence and had a low level of intensity in fish of all sizes. These results were related to the occurrence of the intermediate hosts of the parasites and to the movement of A. silus to deeper water as it increases in size. The intensity of infestation with L. botryophorum increased from south to north. Seasonal variation in recruitment, with a peak immediately after spawning, was reflected in the intensity of infestation, mean size, and percentage of immature specimens of L. botryophorum.The young A. silus are midwater plankton feeders and the mature fish change to a diet that incorporates a high proportion of the crustacean intermediate host of L. botryophorum, probably an amphipod. There is no parasitological evidence of separate populations of A. silus in the west Atlantic.

Morphology and morphometric variation in Lecithophyllum botryophorum (Trematoda: Hemiuridae) in Argentina silus.

New trematode material from the argentine, Argentina silus, of the east and west Atlantic is identified as Lecithophyllum botryophorum. The parasite is redescribed and compared to the original description of the species and to L. anteroporum. Change in size of different anatomical structures is correlated with growth of the trematode. The sequence of development of the parts of the reproductive system is outlined.

Biology of the Atlantic Argentine (Argentina silus Ascanius) on the Scotian Shelf

On the Scotian Shelf, Argentina silus Ascanius was found mainly along the continental slope but extended into the deep-water basins of the central shelf. It was not found in the Bay of Fundy, and only a few were found in the Gulf of St. Lawrence. It was found in largest numbers in depths between 100 and 150 fath (183–275 m) and at temperatures between 4 and 10 C.Although larger fish were usually found deeper, in general argentines from the slope region had a modal length of 21–28 cm and were from 2 to 7 years of age. Argentines taken from Emerald Basin had a modal length of 18–22 cm and were 1 or 2 years of age in autumn, but had a modal length of 30–36 cm and were 6–11 years of age in winter.Spawning occurred in the spring in Emerald Basin with males maturing around 25 cm and females around 30 cm.Since argentines grow slowly after the first few years and do not mature until several years after growth slows down, it is possible that heavy fishing might quickly reduce stocks and catches below current levels.

The Structure and Function of the Gas Bladder in Argentina situs

ABSTRACT Anatomical and histological observations were made on the gas bladder of the soft-rayed marine salmonoid fish Argentina silus, which usually lives at depths of about 200 m. The gas bladder is completely closed but rather unlike other known types of closed gas bladders. It is composed of three tissue layers, which may conveniently be called mucosa, submucosa, and tunica externa. The latter contains a large amount of guanine. The tunica externa is penetrated by numerous blood-vessels, which form a widely distributed rete mirabile of a peculiar ‘bi-dimensional’ type in the submucosa. All vessels reaching the mucosa seem to come from this rete system, and no special ‘resorbent mucosa’ such as occurs in euphysoclistae could be identified. The mucosa is folded, forming an alveolar-like structure of unknown function. The gas gland layer is separated from the lumen of the bladder by smooth muscles and an inner epithelium. The close anatomical association of the gas gland tissue with smooth muscles probably is of importance for gas secretion. Analyses of gases from specimens taken from a depth of about 80 m showed a mean oxygen value of almost 80%, which indicates a similar gas secretory mechanism to that in euphysoclistae. Certain aspects of the physiology of the gas bladder in relation to life in deep water are shortly discussed, and the need for a thorough histological examination of the gas bladder in deep-water salmonids is emphasized.

Abundance of the greater Siil-Smelt (Argentina silus, Ascan.) on the market of Boston, Lincolnshire

<i>Abundance of the greater Siil-Smelt</i> (Argentina silus, <i>Ascan.</i>) <i>on the market of Boston, Lincolnshire</i>

The Great Silver Smelt, Argentina silus, Nilss. An Addition to the List of British Fishes.

By the kindness of Mr. J. Jacobs, to whom the Laboratory is already indebted for many specimens of interest, I received on the 15th June a fine example of the species mentioned above, which had been trawled off the south coast of Ireland. The fish weighed 1 lb. 5 oz., and measured 42 cm., or 16½ inches. Though taken at least a day previously, it was in excellently fresh and firm condition. I have already recorded its capture in a letter to the Field and at a meeting of the Zoological Society, but the locality was inexactly given in each of these communications. I have since learned that the correct locality is 50° 20′ N., 8° 25′ W., or about seventy-five miles true S. of the Old Head of Kinsale, depth seventy-four fathoms. A number of the same species were trawled, and some were found to be excellent eating. I have no means of deciding whether the occurrence of A. silus on the ground indicated is normal or exceptional. If it can be taken in any quantity it should prove a valuable addition to our list of food-fishes.

On the Occurrence of the Norwegian Argentina silus* on the Shore of the Moray Firth, Banffshire.

On the Occurrence of the Norwegian Argentina silus* on the Shore of the Moray Firth, Banffshire. Get access Thomas Edward, A.L.S. Thomas Edward, A.L.S. Search for other works by this author on: Oxford Academic Google Scholar Zoological Journal of the Linnean Society, Volume 15, Issue 87, October 1881, Pages 334–336, https://doi.org/10.1111/j.1096-3642.1881.tb00369.x Published: 23 December 2008