Chemical and Sensory Analysis of Ungutted Offshore (Nonspawning) Capelin (Mallotus villosus) Stored in Ice

1978 ◽  
Vol 35 (7) ◽  
pp. 976-980 ◽  
Author(s):  
J. R. Botta ◽  
P. B. Noonan ◽  
J. T. Lauder

Based on changes in chemical and sensory variables, the keeping time of ungutted offshore capelin (Mallotus villosus) stored in ice was ~ 12 d, which was superior to other pelagic fish such as inshore (spawning) male capelin, Atlantic herring (Clupea harengus harengus) and Atlantic mackerel (Scomber scombrus). Free fatty acid, hypoxanthine, trimethylamine, and moisture content as well as iodine number and muscle pH significantly (P ≤ 0.05) changed during 16 d of iced storage. Although changes in lipid content and peroxide value were statistically significant (P ≤ 0.05), it is questionable whether these changes were chemically significant. Hypoxanthine and trimethylamine appeared to have the most potential for use as indices of sensory quality deterioration during iced storage. Key words: capelin, flavor, free fatty acids (FFA), hypoxanthine, iced storage, odor, overall acceptability, peroxide value, texture, trimethylamine (TMA)

1982 ◽  
Vol 39 (8) ◽  
pp. 1164-1174 ◽  
Author(s):  
R. Courtois ◽  
M. Simoneau ◽  
J. J. Dodson

The study of the spatial and temporal organization of the planktonic community of the middle estuary of the Saint Lawrence River revealed that fish larvae were distributed in such a way as to minimize interactions between species. Smelt (Osmerus mordax) larvae were distributed upstream whereas capelin (Mallotus villosus) and Atlantic herring (Clupea harengus harengus) larvae were found downstream in June 1979. Capelin larvae were more abundant at the surface (0–20 m) whereas herring larvae were concentrated in deeper waters (20–60 m). The ecological separation observed was maintained by multiple physical factors and appeared to be the consequence of species-specific reproductive strategies. The abundance of chaetognaths, euphausiids, and amphipods in deeper waters suggests that these forms could be important predators of fish larvae. Herring larvae may be particularly vulnerable because of their distribution in deep water. Capelin larvae which are very abundant in June could also be vulnerable to predation during the diurnal migrations of the macroplankton. Smelt larvae appear to be little affected by predation from these forms as a result of their distribution in fresher waters.


1978 ◽  
Vol 35 (4) ◽  
pp. 452-456 ◽  
Author(s):  
J. R. Botta ◽  
D. H. Shaw

Whole inshore male capelin (Mallotus villosus) were stored at −23 °C for 2 mo (C2), or 6 mo (C6) prior to thawing, beheading and eviscerating, and refreezing. Though the quality of the twice-frozen product was in both cases inferior to a once-frozen sample, it was still quite acceptable after 2 yr of refrozen storage. As expected, quality was superior in the C2 samples, but in both sets of samples taste deteriorated to a greater extent than texture. Chemical measurement of peroxide value indicated a possible development of rancidity that could not be detected by sensory analysis. Considerable lipid hydrolysis occurred, with the free fatty acids (FFA) at least doubling during storage; increases were greater in C6. In both experiments FFA production correlated with texture, taste, and with extractable protein nitrogen (EPN). Dimethylamine (DMA), trimethylamine (TMA), hypoxanthine, and EPN appeared to be good indicators of storage time and sensory quality. Key words: capelin, dimethylamine (DMA), extractable protein nitrogen (EPN), free fatty acids (FFA), hypoxanthine, peroxide value, refrozen storage, taste, texture, trimethylamine


2009 ◽  
Vol 66 (10) ◽  
pp. 1693-1706 ◽  
Author(s):  
Elvar H. Hallfredsson ◽  
Torstein Pedersen

Predation has been suggested as a cause of substantial mortality of fish larvae to the degree that it might influence recruitment. This field-based study concludes that juvenile herring ( Clupea harengus ) as small pelagic predator can significantly affect mortality rates of the planktonic larvae of capelin ( Mallotus villosus ) in the Barents Sea. Surveys were carried out in the summers of 2001 and 2003. In 2001, juvenile herring were widely distributed and overlapped with capelin larvae over a wide area, whereas in 2003, the herring were more aggregated. The study focused on predation in the areas of predator–prey overlap. Capelin larvae were observed in the herring stomachs at 11 of 24 stations and at 8 of 16 stations where herring were caught in 2001 and 2003, respectively. At those stations, an estimated 7.3% and 9.9% of the capelin larvae were eaten by herring per day in 2001 and 2003, respectively. Statistical models revealed that density of capelin larvae and copepods and occurrence of euphausiids in the stomachs affected the number of capelin larvae per predator stomach. A simplified model with only capelin larvae density as predictor was converted to a functional response relationship using an experimentally derived digestion rate estimate for capelin larvae in herring stomachs.


2010 ◽  
Vol 67 (9) ◽  
pp. 1363-1375 ◽  
Author(s):  
Dag Øystein Hjermann ◽  
Bjarte Bogstad ◽  
Gjert Endre Dingsør ◽  
Harald Gjøsæter ◽  
Geir Ottersen ◽  
...  

The Barents Sea stock of capelin ( Mallotus villosus ) has suffered three major collapses (>90% reduction) since 1985 due to recruitment failures. As capelin is a key species in the area, these population collapses have had major ecosystem consequences. By analysing data on spawner biomass and three recruitment stages (larvae, 0-group, and 1-year-olds), we suggest that much of the recruitment failures are caused by predation from herring ( Clupea harengus ) and 0-group and adult Northeast Arctic cod ( Gadus morhua ). Recruitment is furthermore positively correlated with sea temperatures in winter and spring. Harvesting of maturing capelin on their way to the spawning grounds reduced the abundance of larvae significantly, but this reduction to a large extent is compensated for later in life, as mortality is strongly density-dependent between the larval stage and age 1. Altogether, our study indicates a very high importance of trophic interactions, consistent with similar findings in other high-latitude marine ecosystems.


1981 ◽  
Vol 38 (7) ◽  
pp. 856-859 ◽  
Author(s):  
Charles J. Musial ◽  
John F. Uthe ◽  
Gary R. Sirota ◽  
B. Garth Burns ◽  
Michael W. Gilgan ◽  
...  

We describe the isolation and identification of di-n-hexyl phthalate, a new marine pollutant found in Atlantic herring (Clupea harengus harengus) and Atlantic mackerel (Scomber scombrus). This compound was isolated from extracted lipids by a combination of gel permeation, high performance liquid and column chromatography, and selective precipitation of impurities. Conclusive proof of its structure was obtained from gas chromatographic–mass spectrometric analysis and proton nuclear magnetic resonance spectroscopy. The concentrations of di-n-hexyl phthalate (17–27 μg/g wet weight), which is not a major industrial phthalic acid ester, far exceeded those of dibutyl and di-2-ethylhexyl phthalates, the major industrial phthalic acid esters. Thus the possibility of selective bioaccumulation of DHP in herring and mackerel was indicated. This finding is important in view of the paucity of toxicological information concerning this compound.Key words: phthalic acid ester, di-n-hexyl phthalate (DHP), analysis, mackerel, herring, marine fish, pollution


1994 ◽  
Vol 51 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Pierre-Michel Fontaine ◽  
Mike O. Hammill ◽  
Cyrille Barrette ◽  
Michael C. Kingsley

Stomach contents (n = 138) were examined in harbour porpoise (Phocoena phocoena) caught incidently by commercial fishermen in the estuary and the Gulf of St. Lawrence; 111 stomachs contained food. A total of 4423 otoliths and 11 upper beaks were collected belonging to nine species of fishes and one species of squid. Capelin (Mallotus villosus), Atlantic herring (Clupea harengus), and redfish (Sebastes marinus) were the three most important species in the diet by frequency of occurrence (83, 8, and 4.5%, respectively) and percent occurrence in the stomachs (52, 49, and 8.5%). Capelin and herring also made the greatest mass and caloric contribution to the diet of porpoise (>80%). The estimated mean mass and caloric value of the stomach contents of a nonlactating adults were 958 g and 7007 kJ, respectively.


1984 ◽  
Vol 41 (11) ◽  
pp. 1552-1564 ◽  
Author(s):  
Timothy C. Lambert

Complexities of herring (Clupea harengus) stocks previously alluded to are here explored in detail. Analysis of polymodal larval populations of both herring and capelin (Mallotus villosus) from a number of localities reveals the presence of a succession of larval cohorts over time. Separation of these cohorts in time and space is quantified and similarities and differences between species are indicated. The concept of "feeding range" can be applied in explanation of this cohort phenomenon. I suggest that this reproductive strategy serves to limit intraspecific competition and divides a limited food supply more equitably among the total larval population.


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