Seasonal variations in lipid content of eels (Anguilla australis)

1975 ◽  
Vol 26 (2) ◽  
pp. 271 ◽  
Author(s):  
G Hopkirk ◽  
RBH Wills ◽  
PR Townsend
Keyword(s):  
New Zealand ◽  
Lipid Content ◽  
Seasonal Variations ◽  
Anguilla Australis ◽  
Silver Eels ◽  
Winter Hibernation ◽  
Yellow Eels

Changes in the lipid content of short finned eels (Anguilla australis schimidtii Phillips) obtained from Lake Ellesmere, New Zealand, were determined. The lipid content of yellow eels increased once they resumed feeding after their winter 'hibernation' with the most rapid increase being in the first few weeks. The lipid content of silver eels was found to gradually decline with time.

Effect of body lipid content is linked to nutritional adaptation in the acclimation responses of mesic-adapted Paederus to seasonal variations in desiccation stress

2021 ◽  
Vol 131 ◽  
pp. 104226
Author(s):  
Lee-Jin Bong ◽  
Chia-Yu Wang ◽  
Satomi Shiodera ◽  
Takashi F. Haraguchi ◽  
Masayuki Itoh ◽  
...  
Keyword(s):  
Lipid Content ◽  
Seasonal Variations ◽  
Desiccation Stress ◽  
Body Lipid

Seasonal variations in the composition and thermal properties of New Zealand milk fat: I. Fatty-acid composition

1973 ◽  
Vol 40 (2) ◽  
pp. 207-214 ◽  
Author(s):  
I. K. Gray
Keyword(s):  
Fatty Acid Composition ◽  
Thermal Properties ◽  
Fatty Acid ◽  
New Zealand ◽  
Acid Composition ◽  
Negative Correlation ◽  
Seasonal Variations ◽  
Milk Fat ◽  
Significant Negative Correlation ◽  
Weight Percentage

SummaryThe fatty-acid composition of 17 samples of New Zealand milk fat obtained throughout one dairy season is reported.The weight percentage of butyric (C4:0) acid was significantly correlated with that of caproic (C6:0) acid and that of caprylic (C8:0) acid. Percentages of C6:0and C8:0showed a highly significant correlation with each other and with weight percentages of capric (C10:0) and lauric (C12:0) acids.There was a highly significant negative correlation between palmitic (C16:0) and stearic (C18:0) acids and between C4:0and C16:0acids. Oleic (C18:1) acid showed significant negative correlations with C8:0, C10:0, C12:0, myristic (C14:0) and C16:0acids.

Branchial expression of an aquaporin 3 (AQP-3) homologue is downregulated in the European eelAnguilla anguillafollowing seawater acclimation

2002 ◽  
Vol 205 (17) ◽  
pp. 2643-2651 ◽  
Author(s):  
Christopher P. Cutler ◽  
Gordon Cramb
Keyword(s):  
Northern Blot Analysis ◽  
Transcript Abundance ◽  
European Eel ◽  
Aquaporin 3 ◽  
Quantitative Studies ◽  
Silver Eels ◽  
Polymerase Chain ◽  
Seawater Acclimation ◽  
Yellow Eels ◽  
Specific Mrna

SUMMARYA cDNA encoding the homologue of mammalian aquaporin 3 (AQP-3) was isolated by reverse transcription—polymerase chain reaction from the gill of the European eel. The derived amino acid sequence shares 67-70% homology with other vertebrate AQP-3 homologues. Northern blot analysis revealed two AQP-3-specific mRNA species of 2.4 kb and 7 kb. AQP-3 mRNA is expressed predominantly in the eye, oesophagus, intestine (as found in mammals) and the gill; no expression could be demonstrated in the stomach and only low and sporadic levels in the kidney. Quantitative studies demonstrated that,following the 3-week acclimation of freshwater (FW)-adapted yellow and silver eels to seawater (SW), transcript abundance in the gill was reduced by 76% and 97%, respectively. The half time of branchial AQP-3 mRNA downregulation in yellow eels was approximately 10 h, with a maximal 94% decrease in expression after 2 days in SW (compared to time-matched FW controls). However, in fish acclimated to SW for more than 4 days, the fall in AQP-3 mRNA abundance recovered slightly, such that after 3 weeks, expression was 16% of that in time-matched FW controls. The potential roles for this aquaporin isoform in water or solute transport in the eel gill are discussed.

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
New Zealand ◽  
Management System ◽  
Stock Assessment ◽  
Catch Per Unit Effort ◽  
Commercial Catch ◽  
The North ◽  
Anguilla Australis ◽  
Unit Effort ◽  
Access Rights ◽  
Quota Management

<em>Abstract.</em>—The New Zealand eel fishery comprises two species, the shortfin eel <em>Anguilla australis </em>and the New Zealand longfin eel <em>A. dieffenbachii</em>. A third species, the speckled longfin eel <em>A. reinhardtii</em>, is present in small numbers in some areas. Major fisheries in New Zealand are managed under the Quota Management System. Individual transferable quotas are set as a proportion of an annual total allowable commercial catch. The Quota Management System was introduced into the South Island eel fishery on 1 October 2000 and the North Island fishery on 1 October 2004. Freshwater eels have particular significance for customary Maori. Management policies allow for customary take and the granting of commercial access rights on introduction into the Quota Management System. Eel catches have remained relatively constant since the early 1970s. The average annual catch from 1989–1990 to 2001–2002 (fishing year) was 1,313 mt. Catch per unit effort remained constant from 1983 to 1989 and reduced from 1990 to 1999. Statistically significant declines in catch per unit effort for New Zealand longfin eel were found in some areas over the latter period. For management, an annual stock-assessment process provides an update on stock status.

Studies on the properties of New Zealand butterfat: VII. Effect of the stage of maturity of ryegrass fed to cows on the characteristics of butterfat and its carotene and vitamin A contents

1963 ◽  
Vol 30 (1) ◽  
pp. 59-66 ◽  
Author(s):  
F. H. McDowall ◽  
W. A. McGillivray
Keyword(s):  
New Zealand ◽  
Vitamin A ◽  
Seasonal Variations ◽  
Monozygotic Twin ◽  
Early Summer ◽  
Short Rotation ◽  
Feeding Trials

SummaryIn two outdoor feeding trials with monozygotic twin cows during the spring and early summer months the effects of mature and immature H1 short rotation ryegrass on the composition of the butterfat produced and on the carotene and vitamin A contents of the butterfat and the blood were compared. In both trials the characteristics investigated were markedly affected by the stage of maturity of the grass. The butterfat from cows receiving immature ryegrass was more unsaturated and had higher carotene and vitamin A contents than that from cows receiving mature ryegrass. The blood of cows fed immature ryegrass also contained more carotene than the blood of cows fed mature ryegrass.It is suggested that variation in the stage of maturity of New Zealand dairy pastures throughout the year is an important factor contributing to the seasonal variations in the characteristics and the carotene and vitamin A contents of commercial butterfat. The influence of stage of maturity is probably associated with the quantity and nature of the pasture lipids.

Seasonal Changes in General Condition and Lipid Content of Cod from Inshore Waters

1967 ◽  
Vol 24 (3) ◽  
pp. 607-612 ◽  
Author(s):  
P. M. Jangaard ◽  
H. Brockerhoff ◽  
R. D. Burgher ◽  
R. J. Hoyle
Keyword(s):  
Seasonal Variation ◽  
Nova Scotia ◽  
Lipid Content ◽  
General Condition ◽  
Seasonal Variations ◽  
Seasonal Changes ◽  
Oil Content ◽  
Gadus Morhua ◽  
Male Fish ◽  
Inshore Waters

The seasonal variations in lipid content and general "condition" of cod, Gadus morhua L., from an inshore population have been determined.Four female and four male fish were chosen from 20 live cod brought in monthly from Terence Bay, Halifax County, Nova Scotia, the fish were pooled and the lipid content determined on the flesh, livers, and gonads. The flesh lipids varied from 0.57% to 0.74% and the oil content of the livers from 15% to 75%.The general "condition" of the fish as expressed by [Formula: see text], the liver condition by [Formula: see text], and the fat content of the liver all showed seasonal variation with maxima in the fall and minima in the spring. KF varied from 0.79 to 1.05 and KL from 1.0 to 4.5. No seasonal variation in the amount of flesh lipids could be detected.

Seasonal variations in length of copepods in South Pacific New Zealand waters

1966 ◽  
Vol 17 (2) ◽  
pp. 155 ◽  
Author(s):  
GB Deevey
Keyword(s):  
New Zealand ◽  
Seasonal Variations ◽  
Spring Bloom ◽  
Narrow Temperature Range ◽  
Temperature Range ◽  
Maximal Size ◽  
Cephalothorax Length ◽  
Autumn And Winter ◽  
Cycle Temperature ◽  
Paracalanus Parvus

Measurements of cephalothorax length were made on females and males of Centropages aucklandicus, Acartia clausi, Paracalanus parvus, and Clausocalanus arcuicornis, and on female Calanus australis for the period from April 1964 to May 1965. Centropages aucklandicus and A. clausi increased gradually in length during autumn and winter to maximal size in the spring and were smaller again in summer. Paracalanus parvus was larger in spring and smaller the rest of the year. Calanus australis and C. arcuicornis were large in spring, but during summer they were also large on occasion, possibly because offshore populations had been brought into the area. Length-temperature-phytoplankton correlations showed that in temperate New Zealand waters with a relatively narrow temperature range the seasonal variations in length of all the copepods studied were significantly related to the annual phytoplankton cycle; temperature was an important factor for only two of the species. Some of the species measured are primarily herbivorous whereas others, such as Centropages and Acartia, are probably omnivores. Data are lacking for carnivorous copepods. However, since the spring bloom acts as a stimulus to zooplankton reproduction, it is suggested that all copepods that feed on living food might attain maximal size at around the time of the spring bloom in temperate waters with a relatively narrow temperature range.

Diel feeding and prey selection of three size classes of shortfinned eel (Anguilla australis) in New Zealand

1998 ◽  
Vol 49 (5) ◽  
pp. 421 ◽  
Author(s):  
P. M. Sagar ◽  
G. J. Glova
Keyword(s):  
New Zealand ◽  
Prey Selection ◽  
Microhabitat Use ◽  
Night Time ◽  
Fish Prey ◽  
Size Classes ◽  
Anguilla Australis ◽  
Selection Indices ◽  
Feeding Periodicity ◽  
Selection Of

Benthic macroinvertebrates and three size classes of shortfinned eel (Anguilla australis, Anguillidae) were sampled in a lowland New Zealand stream over a 24-h period in summer to investigate diel feeding periodicity and prey selection. Fish of all three size classes fed mostly from post-dusk to dawn, with larger fish tending to consume a greater proportion of their prey during night-time. The number of prey taxa consumed increased with increasing size of fish. Prey selection indices indicated that: (1) the smallest eels (80–100 mm total length, TL) preferentially consumed ostracods (Crustacea) and larvae of Chironomidae (Diptera) and Psilochorema sp. (free-living Trichoptera); (2) medium-sized eels (101–199 mm TL) preferred larvae of Chironomidae, and Costachorema sp., Hydrobiosis sp. and Psilochorema sp.; and (3) large eels (200–300 mm TL) preferred ostracods, Psilochorema sp. and Hudsonema amabilis (cased Trichoptera). Eels of all size classes showed selection for soft-bodied or easily broken prey over those with hard cases which would have been more difficult to digest. There was considerable overlap in the diets of medium and large eels. Differences in the timing of feeding between the three size classes of eel are explained in terms of microhabitat use; differences in diet are explained in terms of prey size, and are also related to eel size.

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