Evidence for geographical isolation of the early life stages of the white anglerfish, Lophius piscatorius, based on otolith microchemistry

Author(s):  
S.C. Swan ◽  
P.J. Wright ◽  
D.A. Woodroffe ◽  
J.D.M. Gordon ◽  
T. Shimmield

Concentrations of elements in the sagittal otoliths of juvenile white anglerfish (Lophius piscatorius) from five locations in the north-east Atlantic were measured to test for evidence of segregation in the early life stages. The concentrations of some elements, notably copper, were different between locations. As such, the results suggest limited exchange between locations during some period of the early life history. The relevance of these results to our understanding of population structuring is discussed in relation to recent information on anglerfish movements and genetic structuring.

2007 ◽  
Vol 64 (9) ◽  
pp. 1650-1663 ◽  
Author(s):  
Michael R. Heath

Abstract Heath, M. R. 2007. The consumption of zooplankton by early life stages of fish in the North Sea. – ICES Journal of Marine Science, 64: 1650–1663. Previous work has shown that during the 1970s, fish and carnivorous macrozooplankton together consumed ∼22 gC m−2 year−1 of mesozooplankton, principally copepods. Consumption declined to ∼17 gC m−2 year−1 during the 1990s, mainly because of a reduction in fish production. The zooplankton production required to meet this demand seems to be approximately accounted for by estimates of new primary production, but there are additional sinks for zooplankton production attributable to predation by, for example, gelatinous species. Additionally, the consumption of zooplankton by early life stages of fish is difficult to assess and could be larger than implied by the earlier analysis. Here, the role of fish early life stages in zooplankton consumption is re-assessed, and found to be approximately double that previously estimated. Some 28% of the zooplankton consumption by fish is now estimated to be attributable to early life stages, resulting in an estimate of zooplankton consumption by the fish community as a whole 14% higher. Taken overall, the consumption of zooplankton production by fish and other planktivorous predators is now estimated to be 19–25 gC m−2 year−1.


2014 ◽  
Vol 71 (4) ◽  
pp. 907-908 ◽  
Author(s):  
Howard I. Browman ◽  
Anne Berit Skiftesvik

Abstract The themed set of articles that follows this introduction contains a selection of the papers that were presented at the 36th Annual Larval Fish Conference (ALFC), convened in Osøyro, Norway, 2–6 July 2012. The conference was organized around four theme sessions, three of which are represented with articles in this collection: “Assessing the relative contribution of different sources of mortality in the early life stages of fishes”; “The contribution of mechanistic,behavioural, and physiological studies on fish larvae to ecosystem models”; “Effects of oil and natural gas surveys, extraction activity and spills on fish early life stages”. Looking back at the main themes of earlier conferences about the early life history of fish reveals that they were not very different from those of ALFC2012. Clearly, we still have a lot of work to do on these and other topics related to the biology and ecology of fish early life stages.


2011 ◽  
Vol 68 (3) ◽  
pp. 426-443 ◽  
Author(s):  
Ute Daewel ◽  
Myron A. Peck ◽  
Corinna Schrum

We employed a suite of coupled models to estimate the influence of environmental variability in the North Sea on early life stages of sprat ( Sprattus sprattus ), a small pelagic clupeid, and Atlantic cod ( Gadus morhua ), a demersal gadoid. Environmentally driven changes in bottom-up processes were projected to impact the survival and growth of eggs and larvae of these marine fish species in markedly different ways. We utilized a spatially explicit, individual-based model (IBM) to estimate larval fish survival and a 3D ecosystem model (ECOSMO) to provide variable prey fields. The model was applied to each of 3 years (1990, 1992, 1996) specifically characterized by interannual differences in water temperature in late winter and spring. Our results indicated that an important mechanism connecting environmental factors to larval fish survival was the match–mismatch dynamics of first-feeding larvae and their prey, which was species-specific because of (i) differences in the timing and locations of spawning, (ii) the duration of endogenously feeding life stages, and (iii) prey thresholds required for larval survival. Differences in transport processes also played an important role for the potential survival of larvae of both species.


2014 ◽  
Vol 71 (2) ◽  
pp. 203-216 ◽  
Author(s):  
Cóilín Minto ◽  
Joanna Mills Flemming ◽  
Gregory Lee Britten ◽  
Boris Worm

Productivity is a central determinant of population dynamics with consequences for population viability, resilience to exploitation, and extinction. In fish, the strength of a cohort is typically established during early life stages. Traditional approaches to measuring productivity do not allow for interannual variation in the maximum reproductive rate, a parameter governing population productivity. Allowing such process variation provides the ability to track dynamic changes instead of assuming a static productivity regime. Here we develop and evaluate a multivariate stock–recruitment state-space model to simultaneously estimate time-varying stock productivity and synchronicity of dynamics across populations. We apply the method to North Atlantic cod (Gadus morhua) populations, showing that the productivity of early life stages has varied markedly over time, with many populations at historically low productivity. Trends in productivity were similar in some adjacent populations but less regionally coherent than previously thought, particularly in the Northwest Atlantic. Latitudinal variation in the Northeast Atlantic suggests a differential response to environmental change. We conclude that time-varying productivity provides a useful framework that integrates across many dimensions of environmental change affecting early life history dynamics.


Sign in / Sign up

Export Citation Format

Share Document