Ecosystem changes and the effects on capelin (Mallotus villosus), a major forage species

2001 ◽  
Vol 58 (1) ◽  
pp. 73-85 ◽  
Author(s):  
J E Carscadden ◽  
K T Frank ◽  
W C Leggett
Keyword(s):  
Physical Environment ◽  
Population Biology ◽  
Single Species ◽  
Zooplankton Abundance ◽  
Mallotus Villosus ◽  
Northwest Atlantic ◽  
Commercial Fish ◽  
Commercial Exploitation ◽  
Capelin Mallotus Villosus ◽  
The Impact

Capelin (Mallotus villosus), an important forage and commercial fish in the Northwest Atlantic, has exhibited dramatic changes in its biology during the 1990s, coincident with extreme oceanographic conditions and the collapse of major groundfish stocks. Commercial exploitation has not been a serious factor influencing the population biology of capelin in the area. The overall consumption of capelin has declined as predator stock abundances have changed. Data on plankton are sparse, but there appears to have been a decline in zooplankton abundance during the 1990s, and at the same time, a phytoplankton index increased. The impact of the changes in the physical environment has been the subject of previous studies and these are reviewed. The relative impacts of four factors, commercial exploitation, predation, food availability, and the physical environment, on the changes in capelin biology are discussed in the context of capelin as a single species and in the context of the ecosystem. The overall patterns suggest the existence of a "trophic cascade" within the distributional range of capelin in the Northwest Atlantic during the 1990s primarily driven by declines in major finfish predators.

Delayed capelin (Mallotus villosus) availability influences predatory behaviour of large gulls on black-legged kittiwakes (Rissa tridactyla), causing a reduction in kittiwake breeding success

2000 ◽  
Vol 78 (9) ◽  
pp. 1588-1596 ◽  
Author(s):  
Melanie Massaro ◽  
John W Chardine ◽  
Ian L Jones ◽  
Gregory J Robertson
Keyword(s):  
Breeding Success ◽  
Larus Argentatus ◽  
Hatching Date ◽  
Mallotus Villosus ◽  
Predatory Behaviour ◽  
Rissa Tridactyla ◽  
Herring Gulls ◽  
Capelin Mallotus Villosus ◽  
The Mean ◽  
The Impact

During 1998 and 1999, the impact of predation by herring gulls (Larus argentatus) and great black-backed gulls (Larus marinus) on breeding success of black-legged kittiwakes (Rissa tridactyla) at Gull Island, Witless Bay, southeastern Newfoundland, was quantified in relation to the timing of the annual arrival of capelin (Mallotus villosus) to spawn. The frequency of predation attempts by large gulls on kittiwakes was compared among three periods: before the mean hatching date for herring gulls, between the mean hatching date for herring gulls and the arrival of the capelin, and following capelin arrival. The frequency varied significantly among the three periods, being highest after gull chicks hatched but before the capelin arrived. The frequency of gull predation was significantly correlated with the percentage of kittiwake eggs and chicks that disappeared each week. We estimated that 43 and 30% of kittiwake eggs and chicks at Gull Island were taken by gulls in 1998 and 1999, respectively. Kittiwakes have been indirectly (through increased predation by gulls) affected by the delayed arrival and lower abundance of capelin in recent years, which underlines the need to understand multispecies interactions when interpreting the effects of human alteration of the marine environment.

Direct assessment of post-spawning survival of female capelin, Mallotus villosus

2001 ◽  
Vol 81 (2) ◽  
pp. 307-312 ◽  
Author(s):  
S.R. Flynn ◽  
B.S. Nakashima ◽  
M.P.M. Burton
Keyword(s):  
Visual Assessment ◽  
Mallotus Villosus ◽  
Northwest Atlantic ◽  
Histological Technique ◽  
Direct Assessment ◽  
Physiological Evidence ◽  
Capelin Mallotus Villosus ◽  
Potential Impact ◽  
Post Spawning ◽  
Made In

Assessment of spawning survival for female capelin Mallotus villosus (Pisces: Osmeriformes) greater than 12 cm in length was made in the autumn of 1995–1997 comparing a histological technique with existing methods. An intensive macroscopic visual assessment of selected samples from 1995, 1996 and 1997 revealed that 10, 20 and 40% of the females were recovering from spawning respectively each year. Histological assessments of the same fish revealed that 20% in 1995, and nearly 60% of the fish in 1996 and 1997 showed physiological evidence of previous spawning. The proportion of recovering spawners increased with both length and age of the fish. One sample from the Northwest Atlantic Fisheries Organization area of 2J during October 1997 contained nearly 90% recovering fish. The potential impact of the fishery in light of the variability in post-spawning survival of the iteroparous female capelin is discussed.

Gametogenesis in capelin, Mallotus villosus (Müller), in the northwest Atlantic Ocean

2003 ◽  
Vol 81 (9) ◽  
pp. 1511-1523 ◽  
Author(s):  
S R Flynn ◽  
M P.M Burton
Keyword(s):  
Atlantic Ocean ◽  
Reproductive Biology ◽  
Mallotus Villosus ◽  
Northwest Atlantic ◽  
Important Prey ◽  
Resource Managers ◽  
Capelin Mallotus Villosus ◽  
Ovarian Wall ◽  
History Of ◽  
Post Spawning

Capelin (Mallotus villosus) can be regarded as the most important prey item in the northwest Atlantic Ocean. The health and availability of this species are of fundamental importance for the successful growth and reproduction of many other fishes, whales, and birds. In spite of the clear need to understand this species, the life history of the capelin, especially its reproductive biology, is not well understood. This study substantially improves our knowledge of the reproductive biology of capelin and should be of particular interest to resource managers and administrators. Capelin gonads were analysed over three successive seasons using fish collected during beach spawning (June and July 1993, July 1994, July 1995) or trawled between spawnings, with 11 separate samples (fall, winter, and spring from October 1993 to June 1995). Few immature fish were collected in the trawls; 13/130 (10%) males and 3/150 (2%) females. No recovering (postspawning) males were found in the trawls, but 8/150 (5.3%) recovering females were identified on the basis of large residual oocytes (ovulated or unovulated) and (or) (in the fall) a thicker ovarian wall. Recovering females were identified as late as 10 months post spawning on the basis of residual oocytes. The essential semelparity of males was supported by a lack of apparent spermatogonia during advanced spermatogenesis, whereas the females' capacity to spawn in a subsequent year (iteroparity) was confirmed by the presence of small nonvitellogenic oocytes when other cells were in late oogenesis, in addition to the identification of recovering fish. Oocytes were separable into four stages (potential year classes) and changes occurred in all oocyte stages throughout the cycle of oogenesis. Gametogenesis was more advanced in longer fish, indicating that larger fish spawn earlier than smaller fish.

scholarly journals Genetic Structure of Capelin (Mallotus villosus) in the Northwest Atlantic Ocean

PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0122315 ◽  
Author(s):  
Ellen L. Kenchington ◽  
Brian S. Nakashima ◽  
Christopher T. Taggart ◽  
Lorraine C. Hamilton
Keyword(s):  
Genetic Structure ◽  
Atlantic Ocean ◽  
Mallotus Villosus ◽  
Northwest Atlantic ◽  
Capelin Mallotus Villosus

Multivariate Analysis of Meristic Characters of Capelin (Mallotus villosus) in the Northwest Atlantic

1980 ◽  
Vol 37 (4) ◽  
pp. 725-729 ◽  
Author(s):  
J. E. Carscadden ◽  
R. K. Misra
Keyword(s):  
Multivariate Analysis ◽  
Discriminant Function ◽  
Multivariate Analyses ◽  
Mature Male ◽  
Mallotus Villosus ◽  
Meristic Characters ◽  
Northwest Atlantic ◽  
Statistical Procedures ◽  
Stock Discrimination ◽  
Capelin Mallotus Villosus

Counts were made on 11 meristic characters of mature male capelin. The Bonferroni method identified three characters that exhibited significant annual differences. Interpopulation differences were compared using the remaining eight characters, and three capelin stocks were identified. Other studies have tentatively identified at least four stocks, and based on this analysis, meristic characters show only limited promise in separating capelin stocks in the Northwest Atlantic. However, the sequence of statistical procedures used in this study offers potential in other stock discrimination studies.Key words: capelin, Mallotus villosus; meristics, multivariate analyses, Bonferroni method, discriminant function

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