Hermosilla, C. A., Rocha, F., Fiorito, G., González, Á. F., and Guerra, Á. 2010. Age validation in common octopus Octopus vulgaris using stylet increment analysis. – ICES Journal of Marine Science, 67: 1458–1463. Daily periodicity of growth increments in stylets was validated in wild-caught Octopus vulgaris maintained under controlled conditions. It was corroborated by staining the stylets either with oxytetracycline (OTC) or tetracycline (TC), and comparing the number of rings produced with the number of days elapsed. In all, 19 animals (10 males and 9 females; 680–1470 g body weight, BW) were injected with OTC in Vigo (mean 124 mg kg−1), and another six animals (1 male and 5 females; 248–570 g BW) with TC at Naples (mean 120 mg kg−1). The animals were successfully maintained in captivity until sacrificed for up to 6 (one animal), 9 (one animal), 18 (the six animals from Naples), and 21 (17 animals) days. The number of increments counted in transverse stylet sections was 18.9 ± 1.4 and 20.5 ± 1.5 for octopuses maintained for 18 and 21 d, respectively. The mean rate of increment formation was 1.02 increments per day, suggesting a periodicity of 1 increment per day in the stylet. Consequently, the results successfully validate daily increment deposition in O. vulgaris stylets in the size range analysed.
The distribution of the common octopus (Octopus vulgaris) in the Mediterranean and Eastern Atlantic waters is evaluated using two presence-only analyses: The maximum entropy model (Maxent) and the ecological niche factor analysis (ENFA). Maxent predicts those geographical areas that satisfy the environmental or abiotic requirements of a species while ENFA explores the niche and habitat preferences of O. vulgaris. The analyses were implemented recovering the spatial information from 213 octopus presence data collected from surveys and bibliographical records. Together, these analyses provided reasonable estimates of the species distribution and the octopus habitat. Among the gathered set of explanatory environmental variables, sea bottom temperature, sea bottom salinity, surface dissolved oxygen and sea surface chlorophyll-a appear as the main variables involved in O. vulgaris distribution.These results were confronted with the available literature.
A comprehensive literature review was conducted to determine the species richness of all the possible taxa of free-living benthic marine invertebrates in Chile. In addition, the extent of endemism to the Pacific Islands and deep-sea, the number of non-indigenous species, and the contribution that the Chilean benthic marine invertebrate fauna makes to the world benthic marine invertebrate fauna was examined. A total of 4,553 species were found. The most speciose taxa were the Crustacea, Mollusca and Polychaeta. Species richness data was not available for a number of taxa, despite evidence that these taxa are present in the Chilean benthos. The Chilean marine invertebrate benthic fauna constitutes 2.47 % of the world marine invertebrate benthic fauna. There are 599 species endemic to the Pacific Islands and 205 in the deep-sea. There are 25 invasive or non-indigenous species so far identified in Chile. Though the Chilean fauna is speciose there is still a considerable amount of diversity yet to be described, particularly amongst the small bodied invertebrates and from the less well explored habitats, such as the deep-sea.
Information regarding melatonin production in molluscs is very limited. In this study the presence and daily fluctuations of melatonin levels were investigated in hemolymph, retina and nervous system-related structures in the cephalopod Octopus vulgaris. Adult animals were maintained in captivity under natural photoperiod and killed at different times in a regular daily cycle. Levels of melatonin, serotonin (5-HT) and its acid metabolite (5-hydroxyindole acetic acid, 5-HIAA) in the hemolymph, retina, optic lobe, and cerebral ganglion were assayed by HPLC. Melatonin content fluctuated rhythmically in the retina and hemolymph, peaking at night. In the retina, but not in the other neural tissues, the rhythm was opposite to that of 5-HT, which displayed basal levels at night. Also, 5-HIAA levels in the retina were higher during the night, supporting that rhythmic melatonin production could be linked to diurnal changes in 5-HT degradation. The high levels of melatonin found in the retina point to it as the major source of melatonin in octopus; in addition, a large variation of melatonin content was found in the optic lobe with maximal values at night. All these data suggest that melatonin might play a role in the transduction of the light-dark cycle information for adjustment of rhythmic physiological events in cephalopods.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.