Monitoring the Ocean with Cephalopods

DWhatley

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#21
Metal accumulations in different tissues of cuttlefish (Sepia officinalis L., 1758) in the Eastern Mediterranean coasts of Turkey
Önder Duysak 2017 (Springer subscription)

Abstract
In this study, metal concentration levels (Cd, Co, Cr, Ni, and Pb) were investigated in the gill, hepatopancreas, ovary, testis, and mantle of the male and female cuttlefish Sepia officinalis in various stations (Iskenderun, Antalya, Kas, Gazipasa, and Anamur) in Mediterranean coasts of Turkey. Hepatopancreas tissue was a better indicator in terms of heavy metal concentration compared to the other tissues. In general, Cd, Co, Cr, Ni, and Pb accumulation for the male was found more than that of the female, whereas Cd and Ni accumulation was found higher in the female. There was a relationship among the metals in the form of Co > Pb > Ni > Cd > Cr in the mantle tissue. The Pb concentration over the recommended limits was found in cuttlefish of Anamur, Antalya, and Iskenderun stations.
 

DWhatley

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#22
On the way for detecting and quantifying elusive species in the sea: The Octopus vulgaris case study
Q. Mauvisseau, M. Parrondo, M.P. Fernández, L. García, J.L. Martínez, E. García-Vázquez, Y.J. Borrell 2017 (subscription Science Direct)
Abstract
Environmental DNA (eDNA) can be a powerful method for assessing the presence and the distribution of aquatic species. We used this tool in order to detect and quantify eDNA from the elusive species Octopus vulgaris, using qPCRs (SybrGreen protocol). We designed species-specific primers, and set up an experimental aquarium approach to validate the new molecular tool in different controlled conditions. Field validation was conducted from sea water samples taken from 8 locations within an octopus fishery area in the Cantabrian Sea during February–March 2016. A significant positive correlation between the total biomass (g of O. vulgaris within thanks) and the amount of O. vulgaris eDNA detected (p-value = 0.01261) was found in aquarium experiments. The species was also detected by PCR in 7 of the 8 water samples taken at sea, and successfully quantified by qPCR in 5 samples. This preliminary study and innovative method opens very promising perspectives for developing quick and cheap tools for the assessment of O. vulgaris distribution and abundance in the sea. The method could help in a close future for quantifying unseen and elusive marine species, thus contributing to establish sustainable fisheries.
 

DWhatley

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#23
Predatory strategies and behaviours in cephalopods are altered by elevated CO2
BL Spady (@DarkwingedDuck), PL Munday, SA Watson - Global Change Biology
Abstract
There is increasing evidence that projected near-future carbon dioxide (CO2) levels can alter predator avoidance behaviour in marine invertebrates, yet little is known about the possible effects on predatory behaviours. Here we tested the effects of elevated CO2 on the predatory behaviours of two ecologically distinct cephalopod species, the pygmy squid, Idiosepius pygmaeus, and the bigfin reef squid, Sepioteuthis lessoniana. Both species exhibited an increased latency to attack and altered body-pattern choice during the attack sequence at elevated CO2. I. pygmaeus also exhibited a 20% decrease in predation rate, an increased striking distance, and reduced preference for attacking the posterior end of prey at elevated CO2. Elevated CO2 increased activity levels of S. lessoniana comparable to those previously shown in I. pygmaeus, which could adversely affect their energy budget and increase their potential to be preyed upon. The effects of elevated CO2 on predatory behaviours, predation strategies and activity levels of cephalopods reported here could have far-reaching consequences in marine ecosystems due to the ecological importance of cephalopods in the marine food web.
 

DWhatley

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#24
Reproductive performance of Octopus maya males conditioned by thermal stress
Laura López-Galindo, Clara Galindo-Sánchez, Alberto Olivares, Omar Hernando Avila-Poveda, Fernando Díaz, Oscar E. Juárez, Fabiola Lafarga, Jordi Pantoja-Pérez, Claudia Caamal-Monsreal, Carlos Rosas 2018 (full article)

Abstract
Observations of wild male O. maya suggest that temperatures below 27 °C favour their reproductive performance. From these observations we hypothesize that, as in females, the temperature modulates the reproductive performance of adult O. maya males. The study aimed to evaluate the physiological condition, reproductive success, and histological damage in testis of male O. maya exposed to thermal stress, to determine the implications of ocean warming over their reproductive performance. High temperatures (28–30 °C) negatively affect the growth and health of male O. maya. In octopuses maintained at 30 °C, as a consequence of the thermal stress we observed an increment in the haemocytes number, a reduction in the oxygen consumption rate, and an inflammatory process in the testis. The number of spermatozoa per spermatophore was not affected by temperature, but higher spermatophores production was observed at 30 °C. The paternity analysis showed that the offspring had multiple paternity with an average of 10 males contributing in a single spawn. The paternal contribution was affected by temperature with high, medium, or no paternal contribution in animals maintained at 24 °C (control group), 28 °C and 30 °C, respectively. The temperatures from 28 °C to 30 °C deeply affected the reproductive performance of Octopus maya males, suggesting that, as embryos, reproductive performance of adult males of this octopus species can be used as a tool for monitoring thermal changes in Yucatán Peninsula, located at the entrance of Gulf of Mexico.
 

DWhatley

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#25
Editorial: The Digestive Tract of Cephalopods: At the Interface Between Physiology and Ecology
Giovanna Ponte, Eduardo Almansa, Paul L. R. Andrews 2018 (collection of paper topics with links)

The collection of papers included in this Research Topic represents the outcome of some of the activities of the COST Action FA1301, CephsInAction. It emerged from a series of presentations delivered during a workshop in Cascais (Portugal; November 24th, 2015), and from the research activities carried out during Short Term Scientific Missions supported through the COST Action FA1301. The overall aim is to fill some lacunae in knowledge of the digestive tract of cephalopod molluscs. In contrast to other areas of cephalopod biology such as the central nervous system and behavior (e.g., Marini et al., 2017; Nakajima et al.; O'Brien et al.; Shigeno et al.) and the visual system (see Hanke and Osorio), relatively little research has been done on this topic during the last 30 years.
 

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