Bivariate Normal Swimbladder Size Allometry Models and Allometric Exponents for 38 Mesopelagic Swimbladdered Fish Species Commonly Found in the North Sargasso Sea

Saenger, R. Alfred

doi:10.1139/f89-249

Cited by 19 publications

(11 citation statements)

References 8 publications

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“…Other researchers have found that the swimbladders of fish from the myctophid geni that are represented in this study are often uninflated, wax invested, or apparently nonfunctional ͑Brooks, 1977; Neighbors, 1992;Neighbors and Nafpaktitis, 1982;Saenger, 1989͒. The fish of the species investigated here also were rarely filled with only gas.…”

Section: Discussionmentioning

confidence: 51%

Target strength measurements of Hawaiian mesopelagic boundary community animals

Benoit‐Bird

2001

The Journal of the Acoustical Society of America

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A 200-kHz echosounder modified to digitize the envelope of the received echoes directly into a computer was used to measure the ex situ target strength ͑TS͒ of live animals from the Hawaiian mesopelagic boundary community as a function of animal size, tilt and roll angle, and biological classification. Dorsal aspect TS ͑in dB//1 m͒ at 200 kHz was related to the animal's length: myctophid fish TSϭ20 log ͑standard length in cm͒Ϫ58.8, r 2 ϭ0.91, squid TSϭ18.8 log ͑mantle length in cm͒Ϫ61.7, r 2 ϭ0.81, shrimp TSϭ19.4 log ͑length in cm͒Ϫ74.1, r 2 ϭ0.83. Tilting the fish 5°and 10°changed the measured TS by up to 3.0 dB, decreasing TS as the fish was tilted forward and increasing TS as the fish was tilted backwards. In shrimp, forward tilt increased TS while backward tilt decreased TS by up to 3.3 dB. No consistent trend in squid TS change was observed with tilt angle. Roll angles of 5°and 10°increased the TS of all groups by up to 3.0 dB. Myctophid lateral aspect TS was consistently about 6 dB higher than the dorsal TS. Physiological analysis of the fishes' swimbladders revealed that the swimbladder is not the dominant scattering mechanism in the myctophid fishes studied.

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Section: Discussionmentioning

confidence: 51%

Target strength measurements of Hawaiian mesopelagic boundary community animals

Benoit‐Bird

2001

The Journal of the Acoustical Society of America

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“…There could be a biological explanation as well: as the fish increase to maximum size, the swim-bladder also approaches its upper size limit. In this case, it has been observed that the usual positive allometric relationship is replaced by isometric or small negative allometric relationships (Saenger 1989). The negative sign may also be due to the large size of the fish in the samples, especially in winter (the sample contained fish close to L ∞ ).…”

Section: Discussionmentioning

confidence: 99%

Anatomical and physiological factors affecting the swim-bladder cross-section of the sardine Sardina pilchardus

Machias¹,

Τσιμενίδης²

1996

Can. J. Fish. Aquat. Sci.

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Variations in the geometric cross-section of the swim-bladder of the sardine Sardina pilchardus, at different reproductive stages, were examined in relation to fish length, the relative volume of gonads and stomach, and lipid content. Fifty specimens were frozen in liquid nitrogen and sectioned with a cryomicrotome, and the volume and surface measurements of their organs were obtained by computer reconstruction. Equations that calculate the swim-bladder cross-section from the aforementioned variables are given. The contribution of each variable to the variations in the cross-section size and shape was estimated by means of multiple regression analysis. We concluded that during the nonreproductive period, the main variable affecting cross-section is length, whereas during the reproductive period, the effect of gonads is more important than length in the calculation of the swim-bladder cross-section. Consequently, variables other than length should be taken into account when estimating target strength, as the latter is affected by the size of the swim-bladder cross-section.Résumé : On a étudié les variations géométriques de la section transversale de la vessie natatoire de la sardine Sardina pilchardus en rapport avec la longueur du poisson, les volumes relatifs des gonades et de l'estomac et la teneur en lipides, à différentes étapes du processus reproductif. Cinquante spécimens ont été congelés dans l'azote liquide et découpés au microtome, et on a obtenu des mesures du volume et de la surface de leurs organes par reconstruction informatisée. On présente les équations permettant de calculer la section transversale de la vessie natatoire à partir de ces variables. La contribution de chacune des variables aux variations de l'aire et de la forme de la section transversale a été estimée à l'aide d'une analyse de régression multiple. Nous avons conclu que, au cours de la période non reproductive, la principale variable influant sur la section transversale est la longueur, alors que, pendant la période de la reproduction, l'effet des gonades est plus important que celui de la longueur pour le calcul de la section transversale de la vessie natatoire. Par conséquent, il faut prendre en considération d'autres variables que la longueur pour l'estimation de l'effectif de l'espèce étudiée, étant donné que l'aire de la section transversale de la vessie natatoire influe sur cette dernière. [Traduit par la Rédaction]

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“…Factors underlying this difference include differences in bodily composition (i.e. increased water content and decreased bone density and musculature) and concomitantly smaller buoyancy requirements; increased use of lipid to achieve buoyancy (Butler & Pearcy 1972); and maintenance of slight negative buoyancy (Saenger 1989), due to the energetic cost of maintaining the swimbladder volume required for neutral buoyancy. The lower specific swimbladder volume would lead to a reduced target strength in relation to fish length or weight.…”

Section: Relationships Of Fish Size and Tsmentioning

confidence: 99%

Pelagic biomass and community structure over the mid-continental slope off southeastern Australia based upon acoustic and midwater trawl sampling

Ja¹,

Rj²,

Williams³

1997

Mar. Ecol. Prog. Ser.

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We compare estimates of biomass and communlty structure based upon depth-stratified sampling from 0 to 900 m at a site on the continental slope south of Tasmania. Australia, using an EK500 acoustic system with vessel-mounted and deeply towed 38 kHz split-beam transducers and a midwater trawl with opening-closing codend system. Multivariate analyses of the target strength (TS) distributions and of dominant species in the tows provided consistent views of community structure: an epipelagic communlty that was differentiated and mid-depth and deep communities not differentiated on a die1 basis. Peaks in the TS distributions and the estimated TS of key biological groups were congruent, although the in situ TS data indicated that fishes with swimbladders in the size range of myctophids have lower TS (up to 5 dB) than previously predicted for physoclists, possibly due to the smaller volume of gas-filled swimbladders among mesopelagic fishes. There was a progressive increase in modal TS distributions with depth, consistent with the larger mean s~z e of both squids and fishes in the deeper strata. Bionlass was lowest in the dayt~me near-surface stratum, but there were no other trends of biomass with depth. The acoustic estimate of biomass based upon the trawl-derived assessment of community composition was 7-fold higher than the trawl-based volume-swept biomass estimate. This acoustic biomass estimate was 3-fold less than one based upon an assessment of community composition derived from TS distributions. The higher acoustic biomass estimates are consistent with regional estimates of primary production and simple trophodynamic calculations.

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Bivariate Normal Swimbladder Size Allometry Models and Allometric Exponents for 38 Mesopelagic Swimbladdered Fish Species Commonly Found in the North Sargasso Sea

Cited by 19 publications

References 8 publications

Target strength measurements of Hawaiian mesopelagic boundary community animals

Target strength measurements of Hawaiian mesopelagic boundary community animals

Anatomical and physiological factors affecting the swim-bladder cross-section of the sardine Sardina pilchardus

Pelagic biomass and community structure over the mid-continental slope off southeastern Australia based upon acoustic and midwater trawl sampling

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