Larval Cohort Succession in Herring (Clupea harengus) and Capelin (Mallotus villosus)

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.

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.


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.


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.


1998 ◽  
Vol 76 (8) ◽  
pp. 1411-1417 ◽  
Author(s):  
Réjean Hays ◽  
Lena N Measures ◽  
Jean Huot

Capelin (Mallotus villosus) (N = 760) and herring (Clupea harengus) (N = 165) were collected in the St. Lawrence estuary during the summer of 1994 and 1995 to examine the importance of pelagic fish in transmission of Anisakis simplex to cetaceans. Larval A. simplex were removed from fish by means of a pepsin-digest solution or by dissection. Prevalence of A. simplex in dissected capelin was 5%, with a mean intensity of 1.2. Prevalences of A. simplex in herring were 95 and 99%, with mean intensities of 6.2 and 6.8 for pepsin digestion and dissection, respectively. Third-stage larval A. simplex found in capelin and herring were compared with third-stage larvae found in euphausiids and belugas (Delphinapterus leucas) from the St. Lawrence estuary and no differences in size or morphology of larvae from these four hosts were observed. Euphausiids, which harboured moulting second-stage and third-stage larvae, are intermediate hosts of A. simplex. As there was no apparent development of larvae in herring or capelin, these fish are considered to be paratenic hosts of A. simplex in the St. Lawrence estuary.


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