Length–weight relationships of 55 mesopelagic fishes from the eastern tropical <scp>North Atlantic</scp>: Across‐ and within‐species variation (body shape, growth stanza, condition factor)

Czudaj, Stephanie; Möllmann, Christian; Fock, Heino O.

doi:10.1111/jfb.15068

Cited by 16 publications

(7 citation statements)

References 43 publications

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“…Although differences were not significant, net catches showed a tendency for higher biomass, and a higher relative contribution of larger sizes in the more productive Lisboa zone. Taking into account the positive allometric growth of mesopelagic fish (Eduardo et al, 2019;Loṕez-Peŕez et al, 2020;Czudaj et al, 2022) and that our trawl system is biased towards small fish, our results suggest that the differences would be even higher if larger size classes had been collected, and therefore the most productive zone would have a higher overall biomass.…”

Section: Vertical Patternsmentioning

confidence: 59%

Variation in mesopelagic fish community composition and structure between Mediterranean and Atlantic waters around the Iberian Peninsula

Olivar

Castellón²,

Sabatés³

et al. 2022

Front. Mar. Sci.

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Mesopelagic fish populations are characterised by high species richness and abundance, and have been identified as important contributors to the active carbon fluxes in the open ocean. We report variability in communities of mesopelagic fish between five zones around the Iberian Peninsula, i.e. Balears and Alboran in the Mediterranean, and Cadiz, Lisboa and Galicia in the Atlantic. Day and night samples were collected from 7 layers of the water column with a midwater trawl fitted with a multisampler. Temperature and salinity regimes were very different on the Mediterranean and Atlantic sides of the peninsula, with much higher values through the entire water column in the Mediterranean, characterized by a strong pycnocline. The highest productivity was observed off Lisboa, where Chlorophyll a concentrations were two orders of magnitude higher than in any other zone. Samples from the western Mediterranean held 22 fish species, while 67 were found in the Atlantic. The lowest diversity and the highest dominance were observed in Balears, and the highest diversity in Cadiz zone. In all zones, but particularly in those in the Mediterranean, mesopelagic populations were dominated by a high number of small fish with low individual biomasses. The species Benthosema glaciale, Cyclothone pygmaea and Ceratoscopelus maderensis were common in the Mediterranean populations, whereas in the Atlantic, Cyclothone microdon/livida, Valenciennellus tripunctulatus, Ceratoscopelus warmingii and Benthosema suborbitale were the most common species. Temperature and salinity (both at surface and in the mesopelagic zone) were the main environmental factors explaining variability in assemblage composition. A persistent (day-night) deep scattering layer was observed using the vessel-based echosounder in all zones, and was comprised primarily of the gonostomatid Cyclothone spp. Night-time echosounder observations of scattering layers near the surface were observed in Balears, Alboran, Cadiz and Lisboa, where night surface net collections indicated that Myctophidae, Stomiidae and Phosichthyidae migration extended to the upper 100 m. Sternoptychids and the gonostomatid Sigmops elongatus seldom reached the upper 100 m in their night vertical migrations. Night stratified hauls of 30 m resolution carried out in the epipelagic zone showed that abundances maxima of migratory fish coincided with the location of the Chlorophyll a maxima.

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Section: Vertical Patternsmentioning

confidence: 59%

Variation in mesopelagic fish community composition and structure between Mediterranean and Atlantic waters around the Iberian Peninsula

Olivar

Castellón²,

Sabatés³

et al. 2022

Front. Mar. Sci.

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“…With regard to the timing of sampling, this cruise covered the months March and April, and reproductive processes during other seasons have not been investigated. Still, although there appear to be some sampling gaps particularly for larger M. polylepis, the individuals from this cruise range from small and immature to actively spawning and reach or exceed the maximum lengths so far reported (Czudaj et al, 2022;Hulley, 1990) in each species. The three species were selected for analysis because a sufficiently large number of individuals had been caught, and damaged specimens with gonads visible indicated that a range of ovarian developmental phases were present.…”

Section: Methodological Constraintsmentioning

confidence: 62%

“…E. risso undertakes vertical migrations of a limited amplitude (Czudaj et al, 2021). It reaches a maximum length of 84 mm (Czudaj et al, 2022), and its diet consists of planktonic copepods as well as small mesopelagic fish (Battaglia et al, 2016). The family Melamphaidae is an abundant but understudied family of meso-to bathypelagic fishes.…”

Section: Introductionmentioning

confidence: 99%

Reproductive biology of the electric lanternfish Electrona risso (Myctophidae) and the bigscale fishes Melamphaes polylepis and Scopelogadus mizolepis (Melamphaidae)

Knorrn,

Wieben,

Fock

et al. 2023

Journal of Fish Biology

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Key reproductive traits of the Electric lantern fish Electrona risso (Myctophidae, n = 918) and the Bigscale fishes (Melamphaidae) Melamphaes polylepis (n=260) and Scopelogadus mizolepis (n = 649) were investigated for the first time. Specimens of these mesopelagic species were collected in March and April 2015 in the Eastern Central Atlantic (0 – 24° N, 20 – 26° W). Sex ratio was not significantly different from 1:1 in E. risso and M. polylepis, but significantly skewed towards female dominance in S. mizolepis. Reproductive phases were determined macroscopically, and by histological analyses on selected individuals. Female length at 50% maturity (L50) was 55.1 mm standard length (SL) in E. risso, with an observed female maximum length (Lmax) of 81.2 mm SL. M. polylepis females had an L50 of 40.2 mm SL and Lmax of 86.7 mm SL. S. mizolepis had an L50 of 46 mm SL and Lmax of 97.9 mm SL. The three species show histological features of iteroparity, but the E. risso population appears to occur in two year‐classes and experience only one spawning season per lifetime in the study region. All three species are batch spawners. A batch fecundity of 2668 eggs was estimated from one E. risso individual, with a relative batch fecundity of 369 eggs g‐1 gonad‐free body mass. M. polylepis had a batch fecundity of 1027 eggs and a relative batch fecundity of 149 eggs g‐1 (n = 3). S. polylepis had a batch fecundity of 1545 eggs and a relative batch fecundity of 215 eggs g‐1 (n = 21). The median Gonadosomatic Index during the actively spawning phase of E. risso was 4.5, significantly lower than that of M. polylepis (7.5) and S. mizolepis (7.1). No regressing or regenerating phases were observed in this study. Batch spawning in all three species is suggested to be advantageous to cope with intra‐annual variability in food supply and other risks for offspring survival. With what appears to be in effect a (facultative) semelparous strategy in combination with a short lifespan in E. risso, inter‐annual differences would have a great influence on population dynamics of this species. Knowledge is still lacking on temporal aspects of reproduction such as the duration of the spawning season and the frequency of spawning, as well as age and growth.This article is protected by copyright. All rights reserved.

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“…However, the Diaphus-slender morphotype has a more streamlined shape that improves their prolonged swimming ability [ 62 ]. In addition, according to the body shape [ 63 ] two additional morphotypes were described for Diaphus spp. (fusiform: D. dumerilii , D. vanhoeffeni, and L. dofleini ; elongatum: D. fragilis ).…”

Section: Discussionmentioning

confidence: 99%

Stranding of Mesopelagic Fishes in the Canary Islands

Sarmiento‐Lezcano

Couret

Lombarte

et al. 2022

Animals

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Most mesopelagic fishes perform large diel vertical migrations from the deep-sea zone to the surface. Although there is a trade-off between a higher food availability at the upper layers and an energy cost and predation risk, incursion towards the surface also implies a transport by currents, where the fish are exposed to a stranding risk on the coast. Here, we reported the first documented stranding of mesopelagic fishes along the southeast shore of Gran Canaria Island. Our study hypothesized that (1) the influence of the Canary Current, (2) the dominant incidence of the Trade Winds during summer, and (3) the presence of an upwelling filament coupled with an anticyclonic eddy south of Gran Canaria Island were the causative mechanisms of the strandings. Diaphus dumerilii (Myctophidae family) was the main species found as observed from an external morphological analysis using traditional taxonomy. The otolith contour analysis suggested the presence of other Diaphus spp. and Lobianchia dofleini. Nevertheless, the otolith morphological features described in the literature suggested that all the specimens were actually D. dumerelii. Errors in the identification were mainly due to the high intraspecific variability found in the otolith morphology. Even so, two patterns of oval and elliptic shapes were described with significant differences in its morphometry.

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Length–weight relationships of 55 mesopelagic fishes from the eastern tropical North Atlantic: Across‐ and within‐species variation (body shape, growth stanza, condition factor)

Cited by 16 publications

References 43 publications

Variation in mesopelagic fish community composition and structure between Mediterranean and Atlantic waters around the Iberian Peninsula

Variation in mesopelagic fish community composition and structure between Mediterranean and Atlantic waters around the Iberian Peninsula

Reproductive biology of the electric lanternfish Electrona risso (Myctophidae) and the bigscale fishes Melamphaes polylepis and Scopelogadus mizolepis (Melamphaidae)

Stranding of Mesopelagic Fishes in the Canary Islands

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