A density-gradient column for determining the specific gravity of fish eggs, with particular reference to eggs of the mackerel Scomber scombrus

Coombs, S. H.

doi:10.1007/bf00394667

Cited by 94 publications

(81 citation statements)

References 9 publications

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“…What distinguishes our findings is that, while previous studies have noted increases in the density and sinking rates of moribund eggs and larvae (e.g. Blaxter & Ehrlich 1974, Ellertsen et al 1980, Coombs 1981, Yin & Blaxter 1987a, ours is the first study to document the nature of the relationship between density and the probability of mortality over a broad range of densities.…”

Section: Age (Days Post-hatch)contrasting

confidence: 60%

“…While considerable emphasis has been placed on the effects of nutrition on buoyancy changes in larval fish (e.g. Blaxter & Ehrlich 1974, Ellertsen et al 1980, Ncilson et al 1986, Yin & Blaster 1987a, Brousseau 1997, selPeral other phvsiological and abiotic factors are known to influence buoyancy (Shelbourne 1957, Coombs 1981, Nissling el al. 1994, Ponwith R Yeill 1995, Sclafani et al 1997).…”

Section: Introductionmentioning

confidence: 99%

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Osmotic condition, buoyancy change and mortality in larval cod Gadus morhua. A bioassay for assessing near-term mortality

Sclafani¹,

Stirling²,

Leggett³

2000

Mar. Ecol. Prog. Ser.

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In larvae ot marine fish, density differences are known to be associated with nutritional state and osmotic failure We hypothesized that these density measures can be used to predict the nearterm mortal~ty of larvae. Specifically, we predicted increased larval mortality to be positively and continuously associated with increased larval density. Under controlled conditions, we measured (1) the average density (g cm'3) and daily percent mortality of fed and starved larval cod Cadus morhua L, in culture tanks and (2) the relationship between larval density and percent mortality of both fed and starved larvae whose survival was monitored for a 24 h period following density determination. We observed a strong, positive linear relationship between average larval density and average percent mortality in both experiments (r2 = 0.79 and r2 = 0.78 respect~vely). The regression slopes did not differ significantly between expenments. A linear regression on the pooled data yielded a highly significant relationship (rZ = 0.77, p < 0.0001). A second-order polynomial regression was also signlf~cant and improved the fit (R2 = 0.80, p < 0.0001). While the second-order polynomial regression better described the functional relationship between average density and average mortality, the simpler first-order model was judged preferable for predicting near-term mortality. The consistency and strength of the Linear regressions suggests that larval density can be a reliable predictor of larval mortahty. We determined the density of larvae associ.ated with 50% mortality (potential 'critical' density value) using linear, polynomial and logistic regressions. All 3 produced similar 'critical' denslties and we used the linear model to estimate this value. Larval cod having densities >1.0338 g cm-3 have a 50% probability of dying within 24 h. The potential for using larval density to predict the probability of near-term mortality in laboratory and field studies is discussed.

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Section: Age (Days Post-hatch)contrasting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Osmotic condition, buoyancy change and mortality in larval cod Gadus morhua. A bioassay for assessing near-term mortality

Sclafani¹,

Stirling²,

Leggett³

2000

Mar. Ecol. Prog. Ser.

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“…Specific gravity of H. amarus eggs was measured using a density gradient column (Coombs, 1981). The density gradient column used in our experiments (Techne Inc.) included a filling device so that two solutions of different density could be introduced, filling the column from the bottom with progressively denser solution.…”

Section: Specific Gravity Measurementsmentioning

confidence: 99%

“…Platania and Altenbach, 1998), it was initially thought that the fish eggs could be placed on the top of the linear density gradient and that they would sink to a position of neutral buoyancy (Coombs, 1981). However, the eggs introduced in this manner fell continuously in the linear density gradient, reaching the bottom of the cylinder after approximately 1 h, giving no clear indication of the specific gravity of the egg.…”

Section: Specific Gravity Measurementsmentioning

confidence: 99%

Effects of salinity on specific gravity and viability of eggs of a North American minnow (Cyprinidae)

Cowley¹,

Alleman²,

Sallenave³

et al. 2009

Sci. Mar.

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SUMMARY: The influence of salinity on survival, specific gravity, and size of eggs of the endangered Hybognathus amarus (Rio Grande silvery minnow) was studied to provide insight into factors affecting their potential dispersal and fate. Under low salinity conditions egg specific gravity declined significantly in the first hour after spawning as the perivitelline space of the egg filled with water. Egg specific gravity achieved a minimum value approximately 1 h post-spawning and remained approximately constant until hatching, which occurred near 48 h post-spawning at 20ºC. Specific gravity of the egg depended on the salinity of the water surrounding the egg: hardened eggs changed rapidly in diameter and specific gravity when exposed to water of higher salinity. Size and specific gravity of H. amarus eggs also differed when the eggs were incubated in different groundwater sources. Experiments indicated that calcium chloride saline solution had a greater effect on egg specific gravity and size than did solutions of sodium or potassium chlorides. Survival of H. amarus eggs declined sharply at salinity greater than 3 (practical salinity units, PSU) and was only 5% at a salinity of 8. Habitat restoration to benefit H. amarus should consider the salinity of habitats in which eggs incubate.Keywords: fish egg drift, buoyancy, osmosis, survival, Hybognathus amarus. RESUMEN: EFECTOS DE LA SALINIDAD SOBRE LA GRAVEDAD ESPECÍFICA Y LA VIABILIDAD DE HUEVOS DE UNA CARPA NORTEAMERICANA (CIPRINIDAE). -El efecto de la salinidad sobre la supervivencia, gravedad específica y talla de los huevos del ciprínido puesto en peligro de extinción, Hybognathus amarus, fue estudiado para proporcionar información sobre los factores que afectan la dispersión y el destino de los huevos. Bajo condiciones de salinidad baja la gravedad específica del huevo disminuyó de forma significativa durante la primera hora después de la puesta, a medida que el espacio del perivitelino del huevo se fue llenando de agua. La gravedad específica del huevo alcanzó un valor mínimo 1 hora después de la puesta y quedó aproximadamente constante hasta eclosión, que ocurrió alrededor de 48 horas tras la puesta a 20˚C. La gravedad específica del huevo dependió de la salinidad del agua que le rodeaba. Los huevos con corion endurecido cambiaron rápidamente en diámetro y gravedad específica cuando fueron expuestos a agua de salinidad más alta. El tamaño y la gravedad específica de los huevos de H. amarus también se diferenciaron cuando los huevos fueron incubados en diferentes fuentes de agua subterránea. Los experimentos indicaron que la solución salina del cloruro de calcio tuvo un mayor efecto sobre la gravedad específica del huevo que las soluciones de los cloruros del sodio o del potasio. Expuestos a soluciones de salinidad de más de 3 (PSU), la supervivencia de los huevos de H. amarus disminuyó claramente, bajando a sólo el 5% en la solución de 8. La restauración del hábitat con el objetivo de beneficiar a H. amarus debe considerar la salinidad de los hábitats en los...

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“…In addition, (for trials 1 and 3) densities of three eggs (at developmental stage III) per salinity treatment (one egg per replicate) were determined in a salinity gradient column (Coombs, 1981;Nissling et al, 2003). The positions of the eggs in the column were compared with the positions of 4 density floats of known specific gravity (correlation coefficient of the calibration floats >0.99) at 6°C in a temperature controlled laboratory.…”

Section: Egg Buoyancymentioning

confidence: 99%

The influence of different salinity conditions on egg buoyancy and development and yolk sac larval survival and morphometric traits of Baltic Sea sprat (<i>Sprattus sprattus balticus</i> Schneider)

Petereit¹,

Hinrichsen²,

Voss³

et al. 2009

Sci. Mar.

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SUMARY:The small pelagic sprat (Sprattus sprattus) is a key ecologic player in the Baltic Sea. However, there is longterm variability in recruitment which is thought to be influenced by fluctuations in abiotic and biotic conditions experienced during the early life stages. This study concentrates on the influence of different ambient salinities on sprat egg development, egg buoyancy and survival as well as early yolk sac larval morphometric traits. Egg buoyancy significantly decreased with increasing salinity experienced during fertilization and/or incubation experiments. Field egg buoyancy measurements in 2007 and 2008 exhibited annual and seasonal differences in specific gravity, potentially associated with changes in adult sprat vertical distribution. Neither egg development time nor the duration of the yolk sac phase differed among salinity treatments. At eye pigmentation, larval standard length exhibited high variance among individuals but did not differ among treatments. The largest ecological impact of salinity experienced during spawning was the modification the buoyancy of eggs and yolk sac larvae, which determines their vertical habitat in the Baltic Sea. There are strong thermo-and oxyclines in the Baltic Sea, and thus salinity can indirectly impact the survival of these early life stages by modifying the ambient temperatures and oxygen conditions experienced.Keywords: clupeids, vertical distribution, specific gravity, drift, recruitment, spawning stock, adult fish. RESUMEN: INFLUENCIA DE DIFERENTES CONDICIONES DE SALINIDAD EN LA FLOTABILIDAD DE LOS HUEVOS, DESARROLLO Y SUPERVIVENCIA DE LARVAS LECITOTRÓFICAS, Y RASGOS MORFOMÉTRICOS DEL ESPADÍN DEL MAR BÁLTICO (SPRATTUS SPRATTUS BALTICUS SCHNEIDER). -El espadín (Sprattus sprattus)es un pequeño pelágico que juega un papel ecológico clave en el mar Báltico. No obstante, se considera que la variabilidad a largo plazo en el reclutamiento está influenciada por condiciones bióticas y abióticas experimentadas durante los primeros estadios de desarrollo. Este estudio se concentra en la influencia de diferentes salinidades ambiente sobre el desarrollo de los huevos de espadín, su flotabilidad y supervivencia, así como sobre los rasgos morfométricos de las larvas lecitotróficas. La flotabilidad de los huevos disminuye significativamente con los incrementos de salinidad experimentados durante los experimentos de fertilización y/o incubación. Las medidas de flotabilidad en el medio mostraron diferencias en la gravedad específica de carácter anual y estacionales en 2007 y 2008, potencialmente asociadas a cambios en la distribución vertical de los adultos de espadín. Ni el tiempo de desarrollo de los huevos ni la duración de la fase lecitotrófica difirió entre los tratamientos de salinidad. En el estadio de pigmentación de los ojos la longitud estándar de las larvas mostró importante variabilidad entre individuos, pero no entre tratamientos. El mayor impacto ecológico debido a la salinidad experimentada durante la puesta fue la modificación de la flotabilidad de los...

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A density-gradient column for determining the specific gravity of fish eggs, with particular reference to eggs of the mackerel Scomber scombrus

Cited by 94 publications

References 9 publications

Osmotic condition, buoyancy change and mortality in larval cod Gadus morhua. A bioassay for assessing near-term mortality

Osmotic condition, buoyancy change and mortality in larval cod Gadus morhua. A bioassay for assessing near-term mortality

Effects of salinity on specific gravity and viability of eggs of a North American minnow (Cyprinidae)

The influence of different salinity conditions on egg buoyancy and development and yolk sac larval survival and morphometric traits of Baltic Sea sprat (<i>Sprattus sprattus balticus</i> Schneider)

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