The black anglerfish Lophius budegassa, together with its conspecific, the white anglerfish Lophi... more The black anglerfish Lophius budegassa, together with its conspecific, the white anglerfish Lophius piscatorius, have an important role in the fisheries economy of the Mediterranean Sea, reaching catches of 4700 t in the last 8 years representing 33 millions of Euros. Despite that, studies on reproduction of these species are scarce in the Mediterranean and nothing is known about reproduction in L. budegassa. In the present study, the reproductive cycle of the black anglerfish was analysed from specimens caught by commercial trawls in the western Mediterranean (Catalan coast) from June 2007 to March 2009. Macroscopic analysis of the gonads revealed an unusual structure in this species. At all developmental stages males had tubular testes that showed a bean shape in transverse section. Females had ovaries consisting of a flattened band made up of a single layer of oocyte clusters which contained a group of oocytes usually in different stages of maturation. The ovaries were anchored t...
ABSTRACT Seasonal study of the diet and food consumption of juvenile hake has been carried out in... more ABSTRACT Seasonal study of the diet and food consumption of juvenile hake has been carried out in the Central Mediterranean Sea (Southern Tyrrhenian Sea). Fish were the most important food resource in terms of weight (ca. 70%). Among the fish, Myctophidae and Sternoptychidae, which are usually distributed deeper than juvenile hake, are most important. During summer, Ceratoscopelus maderensis constituted up to 21% of weight of all prey, and Maurolicus muelleri represented almost 10%. During autumn M. muelleri became the most important food resource. The way in which these more deeply distributed prey enter shallower food webs relates to the daily vertical migrations of lanternfish. In upper water column strata at night or near dawn they become prey of the juvenile hake. Considering that trophic energy flows primarily downward, in the direction of the productivity gradient, the observed flow of energy from deep strata into epipelagic layers could be considered an inverse energy transfer. Daily food consumption of juvenile hake ranged between 4.11 and 4.72% of the body wet-weight (BWW). The application of a square-root model allowed calculation of the fraction of this consumption derived by ingestion of the more deeply distributed mesopelagic fish. Between 11.6% and 17.8% of food consumption was sustained by this energy flow. Such information is useful for understanding the interaction between communities distributed indifferent depth ranges and to reinforce the idea that marine communities are open systems in which migratory movements can dramatically change the assumptions and results of mass-balance models.
The morphological characteristics of the eyes and the retinae of lanternfish larvae ofLampanyctus... more The morphological characteristics of the eyes and the retinae of lanternfish larvae ofLampanyctus crocodilus,Benthosema glaciale, andMyctophum punctatumwere analyzed in pre-flexion, flexion, and post-flexion stages. Pre-flexion larvae ofL. crocodilus, the species with the shallowest depth distribution, had spherical eyes located antero-laterally on a strongly laterally-compressed head, suggesting a forward binocular visual field.B. glacialeandM. punctatumlarvae live deeper in the water column and had eyes elongated in the dorsal-ventral plane. The eyes ofB. glacialewere prominent, projecting slightly outward from a laterally-compressed head, suggesting a strongly laterally-directed visual field.M. punctaumhad stalked elongated eyes projecting from a dorso-ventrally flattened head. The eyes can be freely rotated allowing lateral, anterior and dorsally-directed vision. A prominent choroidal gland was situated beneath the ventral portion of the eye inM. punctatumandB. glaciale, while a...
Journal of Experimental Marine Biology and Ecology, 2011
Egg masses of oceanic squid accidently collected in the wild have been observed only from a few s... more Egg masses of oceanic squid accidently collected in the wild have been observed only from a few spawning events in aquaria, and as a consequence, the study of their embryos and hatchlings is very limited. Here, we used in vitro fertilization techniques to understand the ...
The black anglerfish Lophius budegassa, together with its conspecific, the white anglerfish Lophi... more The black anglerfish Lophius budegassa, together with its conspecific, the white anglerfish Lophius piscatorius, have an important role in the fisheries economy of the Mediterranean Sea, reaching catches of 4700 t in the last 8 years representing 33 millions of Euros. Despite that, studies on reproduction of these species are scarce in the Mediterranean and nothing is known about reproduction in L. budegassa. In the present study, the reproductive cycle of the black anglerfish was analysed from specimens caught by commercial trawls in the western Mediterranean (Catalan coast) from June 2007 to March 2009. Macroscopic analysis of the gonads revealed an unusual structure in this species. At all developmental stages males had tubular testes that showed a bean shape in transverse section. Females had ovaries consisting of a flattened band made up of a single layer of oocyte clusters which contained a group of oocytes usually in different stages of maturation. The ovaries were anchored t...
ABSTRACT Seasonal study of the diet and food consumption of juvenile hake has been carried out in... more ABSTRACT Seasonal study of the diet and food consumption of juvenile hake has been carried out in the Central Mediterranean Sea (Southern Tyrrhenian Sea). Fish were the most important food resource in terms of weight (ca. 70%). Among the fish, Myctophidae and Sternoptychidae, which are usually distributed deeper than juvenile hake, are most important. During summer, Ceratoscopelus maderensis constituted up to 21% of weight of all prey, and Maurolicus muelleri represented almost 10%. During autumn M. muelleri became the most important food resource. The way in which these more deeply distributed prey enter shallower food webs relates to the daily vertical migrations of lanternfish. In upper water column strata at night or near dawn they become prey of the juvenile hake. Considering that trophic energy flows primarily downward, in the direction of the productivity gradient, the observed flow of energy from deep strata into epipelagic layers could be considered an inverse energy transfer. Daily food consumption of juvenile hake ranged between 4.11 and 4.72% of the body wet-weight (BWW). The application of a square-root model allowed calculation of the fraction of this consumption derived by ingestion of the more deeply distributed mesopelagic fish. Between 11.6% and 17.8% of food consumption was sustained by this energy flow. Such information is useful for understanding the interaction between communities distributed indifferent depth ranges and to reinforce the idea that marine communities are open systems in which migratory movements can dramatically change the assumptions and results of mass-balance models.
The morphological characteristics of the eyes and the retinae of lanternfish larvae ofLampanyctus... more The morphological characteristics of the eyes and the retinae of lanternfish larvae ofLampanyctus crocodilus,Benthosema glaciale, andMyctophum punctatumwere analyzed in pre-flexion, flexion, and post-flexion stages. Pre-flexion larvae ofL. crocodilus, the species with the shallowest depth distribution, had spherical eyes located antero-laterally on a strongly laterally-compressed head, suggesting a forward binocular visual field.B. glacialeandM. punctatumlarvae live deeper in the water column and had eyes elongated in the dorsal-ventral plane. The eyes ofB. glacialewere prominent, projecting slightly outward from a laterally-compressed head, suggesting a strongly laterally-directed visual field.M. punctaumhad stalked elongated eyes projecting from a dorso-ventrally flattened head. The eyes can be freely rotated allowing lateral, anterior and dorsally-directed vision. A prominent choroidal gland was situated beneath the ventral portion of the eye inM. punctatumandB. glaciale, while a...
Journal of Experimental Marine Biology and Ecology, 2011
Egg masses of oceanic squid accidently collected in the wild have been observed only from a few s... more Egg masses of oceanic squid accidently collected in the wild have been observed only from a few spawning events in aquaria, and as a consequence, the study of their embryos and hatchlings is very limited. Here, we used in vitro fertilization techniques to understand the ...
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