Search results for "Clupea"

Oogenesis and reproductive investment of Atlantic herring are functions of not only present but long-ago environmental influences as well

2017

Following general life history theory, immediate reproductive investment (egg mass × fecundity/body mass) in oviparous teleosts is a consequence of both present and past environmental influences. This clarification questions the frequent use of season-independent (general) fecundity formulas in marine fish recruitment studies based on body metrics only. Here we test the underlying assumption of no lag effect on gametogenesis in the planktivorous, determinate-fecundity Atlantic herring (Clupea harengus) displaying large plasticity in egg mass and fecundity, examining Norwegian summer–autumn spawning herring (NASH), North Sea autumn-spawning herring (NSAH), and Norwegian spring-spawning herri…

Throwing down a genomic gauntlet on fisheries-induced evolution

2021

Beginning with studies on crypsis and camouflage, the hypothesis that predators can generate evolutionary change in their prey has a long and rich history (1). Few predators, however, rival humans in their potential to generate selection responses and concomitant phenotypic change on contemporary timescales. In the 1930s, J. B. S. Haldane (2) mused that fishing would be an ideal candidate for such “observable evolution” within a human lifetime, proceeding “with extreme and abnormal speed.” However, it was not until the late 1970s that research on fisheries-induced evolution (FIE) gained a substantive scientific foothold, beginning with thought-provoking work on Canadian whitefish ( Coregonu…

Reconstruction of Atlantic herring ( Clupea harengus ) recruitment in the North Sea for the past 455 years based on the δ 13 C from annual shell incr…

2019

Understanding the recruitment variability of the Atlantic herring North Sea stock remains a key objective of stock assessment and management. Although many efforts have been undertaken linking climatic and stock dynamic factors to herring recruitment, no major attempt has been made to estimate recruitment levels before the 20th century. Here, we present a novel annually resolved, absolutely dated herring recruitment reconstruction, derived from stable carbon isotope geochemistry (δ¹³C), from ocean quahog shells from the Fladen Ground (northern North Sea). Our age model is based on a growth increment chronology obtained from fourteen shells. Ten of these were micromilled at annual resolution…

Detection of Allee effects in marine fishes: analytical biases generated by data availability and model selection

2017

The demographic Allee effect, or depensation, implies positive association between per capita population growth rate and population size at low abundances, thereby lowering growth ability of sparse populations. This can have far-reaching consequences on population recovery ability and colonization success. In the context of marine fishes, there is a widespread perception that Allee effects are rare or non-existent. However, studies that have failed to detect Allee effects in marine fishes have suffered from several fundamental methodological and data limitations. In the present study, we challenge the prevailing perception about the rarity of Allee effects by analysing nine populations of …

Changes in crustacean mesozooplankton and some environmental parameters in the Archipelago Sea (Northern Baltic) in 1976-1984

1990

Abstract The abundance of crustacean mesozooplankton was monitored by monthly sampling in the Archipelago Sea (Northern Baltic) during the years 1976-1984. Changes in the abundance of crustacean mesozooplankton species are compared with changes in water temperature, nutrient levels, chlorophyll-a, salinity and population densities of the Baltic herring (Clupea harengus membras L.). There was a rise of water temperature during the study period (about laC on average). The chlorophyll values were increasing, as were the nutrient levels in winter. Salinity was decreasing (on average 0.5‰ S). The biomass and abundance ofplanktivorous Baltic herring were increasing by about 30 and 50 per cent, re…

Small pelagic fish in the new millennium: A bottom-up view of global research effort

2021

The present review is an outcome of discussions at the ICES-PICES Symposium on Drivers of Dynamics of Small Pelagic Fish convened in Victoria, B.C., Canada in spring 2017.-- This review is a first contribution of a new international Working Group on Small Pelagic Fish started jointly by ICES (WGSPF) and PICES (WG43) to continue world-wide collaboration to advance knowledge on the drivers of populations of SPF.

Effect ofMicrocystis aeruginosa andNodularia spumigena on survival ofEurytemora affinis and the embryonic and larval development of the Baltic herrin…

2003

Laboratory experiments were carried out to investigate the effect of two strains of Microcystis aeruginosa and a strain of Nodularia spumigena on the survival of Eurytemora affinis (Copepoda) and on the embryonic and larval development of the Baltic spring-spawning herring Clupea harengus membras. The trials were made in water taken from Parnu Bay, at a salinity of 3.7–5.1 psu, a constant temperature (15°C ± 1°C in trials with Eurytemora and herring embryos; 18°C ± 2°C with herring larvae), and an oxygen concentration of 8.8–10.4 ppm. The strains tested had a negative impact on the survival of Eurytemora, as well as on the embryonic development and hatching regime of the Baltic herring. In …

Rannan halkoisjalkaisäyriäisten (Mysidacea) silakan (Clupea harengus v. membras L.) mätimuniin ja vastakuoriutuneisiin poikasiin kohdistama saalistus

2007

Caught in the middle: bottom-up and top-down processes impacting recruitment in a small pelagic fish

2022

AbstractUnderstanding the drivers behind fluctuations in fish populations remains a key objective in fishery science. Our predictive capacity to explain these fluctuations is still relatively low, due to the amalgam of interacting bottom-up and top-down factors, which vary across time and space among and within populations. Gaining a mechanistic understanding of these recruitment drivers requires a holistic approach, combining field, experimental and modelling efforts. Here, we use the Western Baltic Spring-Spawning (WBSS) herring (Clupea harengus) to exemplify the power of this holistic approach and the high complexity of the recruitment drivers (and their interactions). Since the early 20…

Potential predation pressure of littoral mysids on herring (Clupea harengus membras L.) eggs and yolk-sac larvae

2008

The predation potential of littoral mysid shrimps (Mysidacea) on Baltic herring (Clupea harengus membras L.) eggs and yolk-sac larvae was studied experimentally. The results showed that littoral mysids feed actively on both eggs and yolk-sac larvae. It was shown that Neomysis integer preys on eggs, which are not attached to the substrate. Alternative food (yolk-sac larvae or zooplankton) did not decrease feeding rate on eggs. Only gravel as a bottom material lowered the ingestion rate to nearly zero. The largest of the mysid species Praunus flexuosus ate yolk-sac larvae more than other mysids and most efficiently. Mysids switched to feed on eggs when larvae and eggs were offered simultaneou…