Measurements of density contrast and sound-speed contrast for target strength estimation of Neocalanus copepods (Neocalanus cristatus and Neocalanus plumchrus) in the North Pacific Ocean

Matsukura, Ryuichi; Yasuma, Hiroki; Murase, Hiroto; Yonezaki, Shiroh; Funamoto, Tetsuichiro; Honda, Satoshi; Miyashita, Kazushi

doi:10.1007/s12562-009-0172-3

Cited by 17 publications

(7 citation statements)

References 27 publications

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“…The overall magnitudes of the measured density values for C. finmarchicus and the slightly increasing trend in g from fall to spring are also in agreement with previous studies on the same species conducted at the higher latitudes of the Northeast Atlantic (Køgeler et al 1987;Knutsen et al 2001). Other studies from the North Pacific on large Neocalanus copepods also found g values in a similar range (Matsukura et al 2009;Smith et al 2010). The low g values for calanoid copepods relative to other zooplankton, reaching close to neutral buoyancy before overwintering, are generally explained by the hypothesis that the lipid content and composition are part of a buoyancy regulation strategy (Visser and Jónasdóttir 1999;Campbell and Dower 2003;Pond 2012).…”

Section: Finmarchicussupporting

confidence: 90%

Accounting for seasonal and composition‐related variability in acoustic material properties in estimating copepod and krill target strength

Sakınan

Lawson

Wiebe

et al. 2019

Limnology & Ocean Methods

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Estimation of abundance or biomass, using acoustic techniques requires knowledge of the frequency dependent acoustic backscatter characteristics, or target strength, of organisms. Target strength of zooplankton is typically estimated from physics‐based models that involve multiple parameters, notably including the acoustic material properties (i.e., the contrasts in density and sound speed between the animal and surrounding seawater). In this work, variability in the acoustic material properties of two zooplankton species in the Gulf of Maine, the copepod (Calanus finmarchicus) and krill (Meganyctiphanes norvegica), was investigated relative to changing season as well as, for the copepod, temperature and depth. Increases in the density and sound speed contrasts of these species from fall to spring were observed. Target strength predictions based on these measurements varied between fall and spring by 2‐3 dB in krill. Measurements were also conducted on C. finmarchicus lipid extract at changing temperature and pressure. The density contrast of the extract varied negatively with temperature, while the sound speed contrast changed by more than 10 % over the temperature and pressure ranges that the organism expected to occupy. C. finmarchicus target strength predictions showed that the combined effect of temperature and pressure can be significant (more than 10 dB) due to the varying response of lipids. The large vertical migration ranges and lipid accumulation characteristics of these species (e.g., the diapause behaviour of Calanus copepods) suggest that it is necessary for seasonal and environmental variability in material properties to be taken into account to achieve reliable measurements.

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Section: Finmarchicussupporting

confidence: 90%

Accounting for seasonal and composition‐related variability in acoustic material properties in estimating copepod and krill target strength

Sakınan

Lawson

Wiebe

et al. 2019

Limnology & Ocean Methods

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“…For the measurement of copepod body mass density, McAllen et al (1998) used a solution of sea salts and deionized water. The density bottle method introducing adult copepods to different mixtures of seawater and glycerol was also used by Greenlaw (1977) and Matsukura et al (2009). Køgeler et al (1987) and Visser & Jonasdottir (1999) used the density gradient column method with solutions of diluted seawater and sugar.…”

Section: Effect Of Salinity On Adult Respiration Ratementioning

confidence: 99%

Calanipeda aquaedulcis and Arctodiaptomus salinus are exceptionally euryhaline osmoconformers: evidence from mortality, oxygen consumption, and mass density patterns

Svetlichny¹,

Hubareva²,

Khanaychenko³

2012

Mar. Ecol. Prog. Ser.

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Mortality, respiration rate, and body mass density of the estuarine copepods Calanipeda aquaedulcis and Arctodiaptomus salinus and their eggs were studied over a wide range of salinities. Empirical hydrodynamic modeling was applied to calculate body mass density using the sinking speed of the copepods. According to the index of median lethal salinity (LS 50 ), the salinity tolerance ranges of C. aquaedulcis and A. salinus reared at 18 psu were 0.1 to 50 and 0.1 to 35 psu, respectively. No significant effect of salinity on the specific oxygen consumption rate was found in the range from 0.1 to 40 psu in both species, while mean body mass density increased iso-osmotically with water salinity from (mean ± SD) 1.053 ± 0.007 to 1.077 ± 0.005 g cm −3 in C. aquaedulcis and from 1.039 ± 0.004 to 1.062 ± 0.007 g cm −3 in A. salinus. However, body density contrast and sinking speed were stable in both species, allowing them to avoid buoyancy problems with changing salinity. The mean mass density of resting eggs in A. salinus gradually increased isoosmotically following gradual changes in salinity. In contrast to resting eggs, the mass density of subitaneous eggs was not altered by changes in the surrounding salinity, suggesting a hysteresis response in these eggs.

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“…Their results showed that the maximum TS values for E. pacifica, calculated from a theoretical scattering model, changed by about 5 dB from spring to autumn. Furthermore, Matsukura et al [23] suggested that g and h are affected by seasonal changes in lipid profiles. In this study, the larval anchovy g and h values were fixed at 1.068 and 1.037, respectively.…”

Section: Discussionmentioning

confidence: 99%

Swimming angle and target strength of larval Japanese anchovy (Engraulis japonicus)

et al. 2011

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Measurements of density contrast and sound-speed contrast for target strength estimation of Neocalanus copepods (Neocalanus cristatus and Neocalanus plumchrus) in the North Pacific Ocean

Abstract: Abstract:The mass density and sound-speed contrasts against surrounding seawater (g and h, respectively) of

Cited by 17 publications

References 27 publications

Accounting for seasonal and composition‐related variability in acoustic material properties in estimating copepod and krill target strength

Accounting for seasonal and composition‐related variability in acoustic material properties in estimating copepod and krill target strength

Calanipeda aquaedulcis and Arctodiaptomus salinus are exceptionally euryhaline osmoconformers: evidence from mortality, oxygen consumption, and mass density patterns

Swimming angle and target strength of larval Japanese anchovy (Engraulis japonicus)

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