ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02901.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The pineal organ in the roach,Rutilus rutilus(L.), is covered by a semi‐transparent area, the pineal window. Beneath this the pineal is attached to a long robust stalk, lying just under the parietal bone. The pineal is attached to the brain through the dorsal sac. Three cell types have been identified histologically. These are the sensory cells, supporting cells and the ganglia cells. The inner segment of the sensory cells respond to PAS and AF staining, while the remaining cells respond to Orange G, LG, or Acid Fuchsin. The evidence suggests that the roach pineal may have a dual photosensory and glandular functio

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02902.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Measurements taken from a series of photographs of otoliths of 37 eels caught in a stretch of river of 150m length were used to prepare a growth curve based on back‐calculated measurements. Values ofL∞= 1045 andK =0.046 were determined. Mean incremental growth calculated as 33 mm per year agreed closely with increments determined from growth observed up to 4 years after tagging eels from the same location. Inconsistencies in results of age determinations based on burned otoliths are described but it is concluded that the technique yields results of sufficient reliability to be used in practical management situati

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02903.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Hatchery‐reared brown trout,Salmo trutta, (f.l., 16–27 cm) were stocked into the Afon Clettwr, Afon Western Cleddau and Afon Dysynni, Wales. The effects of (a) retaining fish caged in the river for 24 h before release, and (b) a period of acclimation to flowing water (up to 0.24 m s−1) in tanks prior to stocking were investigated. Data on percentage recapture and post‐stocking movements were obtained from trapping, electrofishing and tag returns. In‐stream acclimation resulted in a higher percentage recapture and a more limited dispersion of the fish stocked under low river flow conditions, but had no effect on trout stocked into a river where higher water velocities were experienced. Acclimation, in tanks, to a flow of 0.1 ms−1for 14 days led to higher percentage recaptures, whereas acclimation for only 2 days resulted in fewer returns than for unacclimated fish. No differences in fish distribution within the rivers could be attributed to these acclimation

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02904.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The insulin activity of the pancreatic tissues of free‐swimming and aestivated African lungfish,P. annectens(Owen), was bioassayed against standard insulin in rabbits. The hepatic glycogen content and plasma glucose concentration in free‐swimming and aestivated lungfish were also estimated. The liver glycogen content was 64·47 ± 6·32 and 7·19 ± 2·68 mgg−1net wt and the plasma glucose concentration was 37·62 ± 4·22 and 6·39 ± 1·29% in free‐swimming and aestivated lungfish, respectively.Extracts of pancreatic tissue of the lungfish produced a dose‐dependent decrease in the plasma glucose concentration in rabbits. The magnitude of the decrease in plasma glucose concentration produced by extracts from aestivated specimens was significantly smaller (about 26%) compared to that produced by pancreatic extracts from free‐swimming active lungfish (about 37%). The insulin activity of the pancreatic tissue was 0·82 ± 0·02 and 1·27 ± 0·25 iu mg−1dry pancreatic tissue weight in aestivated and free

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02905.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Nine species of fishes are recorded from the inshore waters of Heard and McDonald Islands. These records confirm the affinities of the fish fauna of these islands to that found at the nearest neighbouring islands, the Iles Kerguelen, 380 km to the north‐west on the same submarine plateau. Data on the stomach contents and gonad states ofNotothenia coriiceps coriiceps, N. rossii rossiiandChannichthys rhinoceratusshow some differences from the same or related subspecies at other localities.Notothenia c. coriicepsshows more affinities in feeding and reproduction toN. c. neglectafrom Terre Adelie, Antarctica, than to those from the Scotia Sea, in having a significant proportion of active benthic and benthoplank‐tonic invertebrates in its diet, in spawning in mid‐summer and in having a low relative gonad size.Channichthys rhinoceratushas a slightly more diverse diet and its spawning season is later than in the same species at Iles Kerg

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02906.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The euryhaline status of steelhead trout,Salmo gairdneri, smolts was challenged in sea water for 2 weeks after which half of the total fish population was returned to fresh water. Acclimation continued and created two test populations in 29%osea water and fresh water. Subsequently these fish were exposed in fresh water or sea water to approximately equal hyperbaric dissolved total gas pressures (ΔP) of 190 mm Hg or about 125% of barometric pressure. Sea water was easier to supersaturate with air and required only about 10% of the entrained air which was required in fresh water at the same temperature and pressure. Mean time to first mortality was sooner in sea water. Mean times to mortality (10–50%) were not significantly different between fresh water and sea water, but there was a noticeable trend for longer survival in fresh wat

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02907.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Vitamin D3(1000 iu 100 g−1body wt) was administered to the freshwater mud eel,Amphipnous cuchia, which was maintained either in tap water or a calcium‐rich environment. Elevation of serum calcium levels was observed after the Vitamin D3administration. This response was faster in the fishes which were maintained in a calcium rich environment after the vitamin D3administrat

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02908.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

An analysis of the stomach contents of 0+ and 1 + Atlantic salmon parr,Salmo salar, introduced into a Scottish hill loch showed that benthos, plankton, and surface organisms were all taken. Molluscs comprised a relatively small proportion of the food material, probably because they are less active than other animal groups. The most abundant plankter wasDaphnia hyalina. Cyclopsspp. were scarce and noDiaptomusspp. were present in the stomachs despite their abundance in the loch plankton. Laboratory experiments indicated that copepods were difficult to capture and thatD. hyalinawas the organism most frequently selected, even when larger individuals of this species were removed from the environment. Differences between the results from the Scottish loch and similar work in Wales, Sweden and Canada are discussed.

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02909.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Juvenile red drum,Sciaenops ocellatus, measuring 40–49 mm s.l. tolerated abrupt transfer from 28%osalinity sea water to fresh water (

ISSN:0022-1112    

DOI:10.1111/j.1095-8649.1983.tb02910.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY