scholarly journals Ⅰ-4. Basis and application of history estimation using vertebral centrum of teleost fishes

2021 ◽  
Vol 87 (5) ◽  
pp. 545-545
Author(s):  
YOSHIKAZU KATO ◽  
HIROYUKI TOGASHI
Keyword(s):  
2020 ◽  
Vol 33 ◽  
pp. 15
Author(s):  
Roi Martínez-Escauriaza ◽  
Claudio Vieira ◽  
Lídia Gouveia ◽  
Nuno Gouveia ◽  
Margarida Hermida

Data obtained from licenses of spearfishers and surveys conducted in 2004 and 2017 allowed for the analysis, for the first time, of the practice of spearfishing in the Madeira archipelago. Only a small percentage of the population practices spearfishing, mostly local young men. Most of them practice the activity with a partner throughout most of the year and along most of the island's coastal areas, although preferentially along the North and Southeast coast. Results show how, in recent years, despite the population of spearfishers decreasing, the abundance in the annual catch potentially increased, probably due to the higher investment of time in this activity. It has been observed that many fishers complement their catches with manual collecting of invertebrates. Overall, 40 teleost fishes and also 4 crustaceans and 8 molluscs were identified. The most frequently captured fish species were parrotfish and white seabream, while limpets were the most collected invertebrates in both selected periods.


2014 ◽  
Vol 10 (9) ◽  
pp. 20140538 ◽  
Author(s):  
Leon Green ◽  
Fredrik Jutfelt

Increased carbon emissions from fossil fuels are increasing the p CO 2 of the ocean surface waters in a process called ocean acidification. Elevated water p CO 2 can induce physiological and behavioural effects in teleost fishes, although there appear to be large differences in sensitivity between species. There is currently no information available on the possible responses to future ocean acidification in elasmobranch fishes. We exposed small-spotted catsharks ( Scyliorhinus canicula ) to either control conditions or a year 2100 scenario of 990 μatm p CO 2 for four weeks. We did not detect treatment effects on growth, resting metabolic rate, aerobic scope, skin denticle ultrastructure or skin denticle morphology. However, we found that the elevated p CO 2 group buffered internal acidosis via accumulation with an associated increase in Na + , indicating that the blood chemistry remained altered despite the long acclimation period. The elevated p CO 2 group also exhibited a shift in their nocturnal swimming pattern from a pattern of many starts and stops to more continuous swimming. Although CO 2 -exposed teleost fishes can display reduced behavioural asymmetry (lateralization), the CO 2 -exposed sharks showed increased lateralization. These behavioural effects may suggest that elasmobranch neurophysiology is affected by CO 2 , as in some teleosts, or that the sharks detect CO 2 as a constant stressor, which leads to altered behaviour. The potential direct effects of ocean acidification should henceforth be considered when assessing future anthropogenic effects on sharks.


1994 ◽  
Vol 4 (1) ◽  
pp. 126-128 ◽  
Author(s):  
G. W. Barlow
Keyword(s):  

Development ◽  
1968 ◽  
Vol 19 (2) ◽  
pp. 109-119
Author(s):  
Judith Shulman Weis

In teleost fishes, unlike many other vertebrates, the spinal cord originates as a solid structure, the neural keel, which subsequently hollows out. Unlike vertebrates in which the neural tube is formed from neural folds, and where the neural crest arises from wedge-shaped masses of tissue connecting the neural tube to the general ectoderm, teleosts do not possess a clear morphological neural crest. Initially, the dorsal surface of the keel is broadly attached to the ectoderm as described by Shepard (1961). As the neural primordia become larger and more discrete, the region of attachment narrows, and cells become loose (the ‘loose crest stage’). These cells represent the neural crest. Subsequently they begin to migrate and to differentiate into the various derivatives of neural crest. Both sensory and sympathetic neurons arise from neural crest. At the time of their migration the cells are not morphologically distinguishable.


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