Variability in growth rates of larval haddock in the northern North Sea

Gallego,; Heath,; Basford,

doi:10.1046/j.1365-2419.1999.00101.x

Cited by 18 publications

(18 citation statements)

References 29 publications

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“…2002. Looking to otolith growth as a proxy for somatic growth, recent otolith growth is only significantly correlated with previous growth history over the last 4 to 8 increments, which is in accordance with observations of other marine fish larvae (Gallego et al 1996(Gallego et al , 1999. Thus, during development considerable variation in the otolith growth trajectory may occur independently among individuals, causing alterations in the population growth-rate hierarchy.…”

Section: Otolith Characteristicssupporting

confidence: 83%

Growth and mortality patterns evaluated from otolith microstructure in Atlantic cod Gadus morhua larvae reared on different feeding regimes in mesocosms

Meeren

Moksness²

2003

Mar. Ecol. Prog. Ser.

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The objective of this work was to test the hypothesis that in a situation where predators are excluded growth and mortality rates of cod larvae should be independent. This was evaluated from distributions of otolith increments in larvae sampled at different times of development. The mesocosm experiment was carried out in four 5.2 m 3 plastic-bag enclosures placed along a raft system in a 20 000 m 3 seawater pond used for zooplankton production. Two different feed regimes (low and high ration, each in 2 enclosures) were set up on the basis of a fixed specific growth rate (SGR) applied in a bioenergetic model. Cod larvae showed a very dynamic relationship to food availability and larval growth. An increase in prey size after Day 20 had profound effects on otolith growth, which responded rapidly to availability of suitable prey. Thus, a short-term change in feeding conditions seems to be easily tracked in otoliths of cod larvae. The overall relationship between otolith radius and larval length was not linear, indicating a certain degree of decoupling between otolith and somatic growth. In a situation with adequate feeding conditions and exclusion of predators, mortality was not clearly dependent on otolith growth or size. This indicates that no strong inherent mechanisms in the larvae are responsible for growth-or size-dependent mortality.

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Section: Otolith Characteristicssupporting

confidence: 83%

Growth and mortality patterns evaluated from otolith microstructure in Atlantic cod Gadus morhua larvae reared on different feeding regimes in mesocosms

Meeren

Moksness²

2003

Mar. Ecol. Prog. Ser.

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“…Descriptions of the hydrographic conditions during the cruise are presented in MacKenzie et al (1998) and Gallego et al (1999). The main feature of relevance for the present study was the weakly strati®ed and nearly isothermal water column present during the cruise.…”

Section: Hydrographymentioning

confidence: 90%

“…A full description of the larval and hydrographic sampling is presented by Gallego et al (1999). Samples of Melanogrammus aegli®nus larvae were collected in time series fashion at 6-h intervals for a period of 10 d (8 to 19 May 1996); larvae were also collected 29 April to 6 May 1996 in the same area, and a small number of these larvae were included in size-based analyses of enzyme activity.…”

Section: Methodsmentioning

confidence: 99%

Diel variability of feeding activity in haddock ( Melanogrammus aeglifinus ) larvae in the East Shetland area, North Sea

et al. 1999

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Investigations of factors aecting feeding success in ®sh larvae require knowledge of the scales of variability of the feeding process itself and the indices used to assess this variability. In this study, we measured short-term (diel) variability in feeding rates of wild haddock (Melanogrammus aegli®nus) larvae four times per day during a 10-d cruise in the northern North Sea. Feeding activity was evaluated using indices of gut fullness, prey digestive state and biochemical measurements (tryptic enzyme activity). The gut fullness and the enzyme activity indices indicated moderate to high rates of food consumption throughout the cruise. Time series analysis of the three indices showed signi®cant diel variability in all indices and enabled identi®cation of signi®cant lags between food uptake and peak digestive enzyme activity. The typical pattern of food consumption and digestion was characterized by maximal ingestion of prey early in the evening (19:00 hrs) and peak digestive enzyme activity at 01:00 hrs. The time scale over which enzyme activities reacted to prey ingestion was ca. 6 h, and is consistent with expectations from controlled laboratory experiments with other larval ®sh species. Signi®cant diel variability in tryptic enzyme activity suggests that attempts to relate this measure of feeding success to other variables (e.g. food concentrations) should take care to accommodate natural cycles in feeding activity before making statistical comparisons.

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“…This 24% increase in photoperiod could also have contributed to the higher growth and development rates observed in late-hatched fish. In another example, Gallego et al (1999) concluded, 'Daily larval haddock growth variability, estimated from otolith microstructure analysis, was independent of the measured variability of the physical and biological environment of the larvae. '…”

Section: Role Of Photoperiod and Temperature In Determining Larval Grmentioning

confidence: 99%

“…At other times there appears to be more than sufficient prey available to saturate larval feeding (e.g. MacKenzie et al 1990, Gallego et al 1999, Baumann et al 2003, Lough et al 2005. …”

mentioning

confidence: 99%

Ontogenetic and seasonal trends in recent growth rates of Atlantic cod and haddock larvae on Georges Bank: effects of photoperiod and temperature

Buckley¹,

Caldarone²,

Lough³

et al. 2006

Mar. Ecol. Prog. Ser.

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Growth rate is a key demographic factor affecting survival and recruitment of marine fishes. Yet in the field, the patterns of change in growth rate with development and the effects of environmental variability on growth are poorly understood. We examined several factors that may contribute to the observed variability in recent (i.e. 2 to 4 d before sampling) growth and survival of Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus larvae on the southern flank of Georges Bank for the years 1995 through 1999. For both species, strong ontogenetic and seasonal trends in larval growth rates were apparent. A rapid initial increase in specific growth rate with larval size was observed in both species, followed by a stanza with little change in specific growth rate and finally a gradual increase with size to a maximum specific growth rate. For larva of any given size, growth rate increased as the season progressed. A variety of models were used to explore and describe the relations among growth rate, larval size, photoperiod, temperature and other variables. Generalized additive models (GAMs) with both larval size (protein content) and photoperiod terms explained 48% and 61% of the variability observed in recent growth of cod and haddock, respectively. Residuals from these models were used to examine the effects of other factors on estimated growth rates. Salinity, water density (sigma-t, σ t ), distance along the Bank, bottom depth, temperature (T) and residual T (observed T minus the long-term mean for a given day of the year) explained small but significant portions of the residual variability in larval growth rates. These data and other considerations suggest that, while both increasing photoperiod and temperature contribute to the increase in larval growth rates observed each spring, photoperiod rather than temperature was the better proxy for the seasonal trend in larval growth rates between March and May on Georges Bank. Feeding conditions and growth of larval Atlantic cod and haddock were poor during the late winter and spring of 1995 compared with those from 1997 to 1999.KEY WORDS: Atlantic cod · Haddock · Larvae · Growth · Photoperiod · Temperature · Diel trends Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 325: 2006 agreement, however, that knowledge of the factors affecting growth and survival during the first year of life is key to understanding the linkages between the physical and biotic environment and fish production (Leggett & Deblois 1994).Rapid growth and high mortality characterize the larval stage of most marine fishes. The rare survivor increases in mass by 1 to 2 orders of magnitude from hatching through metamorphosis to the juvenile stage. The rates of growth and mortality together determine the rate of change in the biomass of a cohort. Interannual variability in these rates coupled with fluctuations in egg production can lead to large fluctuations in recruitment and year-class size (Houde 1989). While larval mortality...

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Variability in growth rates of larval haddock in the northern North Sea

Cited by 18 publications

References 29 publications

Growth and mortality patterns evaluated from otolith microstructure in Atlantic cod Gadus morhua larvae reared on different feeding regimes in mesocosms

Growth and mortality patterns evaluated from otolith microstructure in Atlantic cod Gadus morhua larvae reared on different feeding regimes in mesocosms

Diel variability of feeding activity in haddock ( Melanogrammus aeglifinus ) larvae in the East Shetland area, North Sea

Ontogenetic and seasonal trends in recent growth rates of Atlantic cod and haddock larvae on Georges Bank: effects of photoperiod and temperature

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