Haematological changes in an Antarctic teleost,Trematomus bernacchii,following stress

The effect of an acute increase in temperature, exhaustive exercise and hypoxia on the haematology of the benthic Antarctic teleost, Trematomus bernacchii was investigated. High temperature and hypoxia caused the biggest changes to the blood, with increases in haematocrit, haemoglobin concentrations and plasma chloride levels. The spleen decreased in mass. Exercise produced the smallest changes. Changes were substantially less than reported for the more active cryopelagic species Pagothenia borchgrevinki. The magnitude of the haematocrit increase is discussed in relation to life-style of fish living in the Antarctic.     

Changes in the blood parameters of an air-breathing fish during different respiratory conditions.

Some of the blood parameters recorded in an air-breathing eel, Amphipnous cuchia under normal respiratory condition during non-breeding period (September-April) are haemoglobin (Hb) concentration 19.26%, haematocrit value 56.16%, RBC number 1.71 million/mm3, RBC size 18.86 X 9.70 mum, mean corpuscular haemoglobin (MCH) 113.4 ng, mean corpuscular haemoglobin concentration (MCHC) 34.2%, blood sugar 77 mg% and ascorbic acid 0.435 mg%. The higher concentration of haemoglobin (19.26%) appears to be related to its obligatory air breathing habit and habitat in a water of low oxygen content. Though a definite trend of increase in the haemoglobin and haematocrit concentration with an increase in the body weight of the fish was lacking, variations were clearly marked related to intrinsic activity of the fish connected with different respiratory conditions. Asphyxiation in a submerged but continuous flow of water (liter/h) for 5 1/2 h resulted in an increase in the above-mentioned parameters to an appreciable extent. These increases were 0.23 million/mm3 in the number of erythrocytes, 6.16% in haemoglobin concentration, 10% in haematocrit value, 20% in blood sugar and 35% in ascorbic acid content. The mean corpuscular haemoglobin showed a decline of 6.2%. Exclusive aerial breathing for 5 1/2 h also caused 7.4% increase in haemoglobin concentration, 9.4% in haematocrit value, 0.14 million/mm3 in RBC number, 20% in blood sugar level, 9% in ascorbic acid content but almost no change in mean corpuscular haemoglobin. The average surface area for diffusion of gases appeared to have reduced by 6.8 mum2 per RBC.     

Feeding ecology of larval and juvenile American shad (Alosa sapidissima) in a small pond

Release ponds are used as part of a multifacet effort to restore American shad ( Alosa sapidissima ) in the upper Susquehanna River basin. Little information exists, however, on the feeding ecology of young shad in small ponds. Consequently, we examined feeding ecology and prey selection of 299 larval and 299 juvenile American shad in a small pond during spring and summer. Larval shad mainly consumed copepods (37.7%) and cladocerans (37.4%) whereas juvenile shad ate chironomids (43.1%) and ostracods (28.4%). Larval and juvenile shad exhibited diel variation in diet composition and feeding periodicity. Food consumption by shad was minimal at night; feeding activity was highest during the day, peaking at 2000 h for both larvae and juveniles. Electivity values of shad larvae for prey taxa were highest for cladocerans (+0.27) and lowest for ostracods (−0.07). Electivity values of juvenile shad were highest for chironomids (+ 0.21) and ostracods (+ 0.09), and lowest for copepods (− 0.08) and baetids (− 0.14). Our data indicate differences in diet composition, prey preference and, to a lesser extent, feeding patterns between larval and juvenile American shad in small pond environments.     

White sturgeon (Acipenser transmontanus) passage at the Dalles Dam, Columbia River, USA

White sturgeon (Acipenser transmontanus) ≥95 cm TL were monitored using acoustic and radio telemetry at a large hydroelectric dam (the Dalles Dam) on the Columbia River, during March 2004 through November 2005 to determine timing and routes of passage and to characterize general movements. Transmitters were surgically implanted into 148 fish during the study; 90 were released into the tailrace and 58 into the forebay. We documented 26 passage events by 19 tagged fish: eight upstream via fish ladders and 18 downstream, mostly through open spill gates. During the study 17 fish entered the two ladders one or more times; 11 entered only the east ladder, three entered only the north ladder, and three entered both ladders at sometime. Residence time within the ladders by individual fish was variable, ranging from about 1 min to nearly 6 months (median = 7.7 h). Only six fish successfully ascended the east ladder, one fish twice. We could not unequivocally determine which fish ladder one fish used to pass upstream. Differences in construction between the north and east fish ladders may account for the greater success of the east fish ladder in passing sturgeon upstream. Changes to operations at hydroelectric dams to benefit migrating anadromous salmonids may influence upstream or downstream passage by white sturgeon. Altering patterns and timing of spill discharge, altering fish ladder entrance attraction flows, and the use of lights, sound, and partial barriers to direct other species of fish to preferred passage routes have unknown effects on sturgeon passage. A better understanding of the consequences to the metapopulation of increasing or precluding upstream or downstream passage is needed.     

Why migrate during the day: a comparative analysis of North American birds

Migration can take place primarily during the day or at night, or during both depending on the species. Why the timing of migration varies among species has been the object of much research but the underlying ecological processes are still unclear. Proximally, migration timing may be influenced by the timing of other activities or may be more prevalent in species that migrate over long distances. Adaptive scenarios emphasize the reduction in flight costs at night especially in smaller species and the advantages of travelling in groups during the day to locate staging sites more efficiently. I used phylogenetic independent contrasts to examine these hypotheses in all North American nesting birds. I uncovered 24 evolutionary transitions in migration timing, most of which involved a switch from nocturnal to diurnal migration. Few of these transitions involved a concomitant change in the timing of foraging habits or migration distance. However, species in diurnal clades were larger, travelled in larger flocks and were generally more sociable than their nocturnal counterparts. The results support the hypotheses that a reduction in flight costs and the ability to pool information from companions are associated with migration timing in North American bird species.     

Some haematological responses of normal and splenectomized rainbow trout Salmo gairdneri to a 12% blood loss

Anaemia can be induced in Rainbow trout by removing 12 % of the blood volume by cardiac puncture. Recovery from such an anaemia has been monitored in both normal and splenectomized fish. After the bleeding there is a decrease in red cell numbers, haematocrit and blood haemoglobin concentration. Although recovery in normal trout was not complete within 27 days, which was the period of the observations, it was seen as a replenishing of red cell numbers, haematocrit and blood haemoglobin concentration. Mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC), both depressed by the bleeding, did not appear to recover during the experimental period.
Splenectomy reduced erythropoietic intensity. After bleeding all the parameters studied were more depressed than those found in normal trout, and recovery was not noted. Blood haemoglobin and red cell numbers did not have the same post-bleeding pattern as normal individuals; MCH and MCHC values remained markedly depressed.
Splenic involvement was further demonstrated by bleeding trout for a second time from both normal and splenectomized groups. In contrast to the response of normal animals, there was a further deterioration of red cell numbers and blood haemoglobin concentration in splenectomized individuals.     

Effect of polychlorinated biphenyls (Delor 103) on haematological and enzyme parameters of the rainbow trout Oncorhynchus mykiss

Rainbow trout at a weight of 223+/-12 g (mean+/-SD) were experimentally injected with a technical mixture of Delor 103 to evaluate the red blood cell indices (red blood cell count, haematocrit, haemoglobin, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration) and some biochemical and enzyme parameters of the blood plasma (total protein, glucose, inorganic phosphate, total calcium, sodium, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase). Delor 103, administered by the i.p. route at a concentration of 0.24 g kg(-1) 120 h(-1), caused an increase in the red blood cell counts, haematocrit values, haemoglobin concentrations, inorganic phosphate, alanine aminotransferase and lactate dehydrogenase. The sodium level fell. The fish injected with Delor 103 showed a relative decrease in the lymphocyte count and a relative increase in the count of neutrophile band forms.     

Regenerative capacity of the spleen in a splenectomized fish, Channa punctatus Bloch, with related investigations into changes in peripheral blood and haematopoiesis

The present investigation has provided evidence by a simultaneous study of the regenerating spleen, peripheral blood and the kidney of the haematopoietic tissue to establish the role of the spleen in the development of circulating blood cells in Channa ( Ophiocephalus ) punctatus Bloch. Regeneration of the spleen after eight to nine weeks of splenectomy was shown to be complete. Weekly observations a fortnight after splenectomy are recorded with reference to spleen morphology and weight, erythrocyte and differential leucocyte counts, haemoglobin content, haematocrit value and related red cell indices (MCV, MCH, MCHC). The results show that splenectomy leads to a macrocytic hypochromic anaemia and leucopenia, resulting in 25% reduction in haemoglobin content and a decrease in leucocyte numbers in five weeks following splenectomy. Thrombocytes and neutrophils show a relative ( P < 0·01) increase. The leucopenia is caused by large and small lymphocytes, eosinophils and basophils whose number was reduced from 50% to 67%.     

Cardiac remodelling of Atlantic halibut Hippoglossus hippoglossus induced by experimental anaemia with phenylhydrazine

Phenylhydrazine injections (0.3 mg kg(-1) , followed by a second injection of 0.1 mg kg(-1) 7 days later) induced a reproducible and stable anaemia in Atlantic halibut Hippoglossus hippoglossus, reducing the haematocrit and haemoglobin by 70.0 and 75.5%, respectively, over 3 weeks. There were no changes in blood electrolyte or lactate concentrations, although anaemic fish showed a 37.5 and 33.0% increase in cardiac somatic index and ventricular somatic index, respectively, compared with dimethyl sulphur oxide (DMSO) and saline vehicle controls. Changes in cardiac somatic indices did not correlate with the ratio of ventricular length:height and length:width did correlate with haematocrit and haemoglobin indicating that changes in cardiac shape may occur as a function of anaemic hypoxemia.     

Optimal swimming speed in head currents and effects on distance movement of winter-migrating fish

Migration is a commonly described phenomenon in nature that is often caused by spatial and temporal differences in habitat quality. However, as migration requires energy, the timing of migration may depend not only on differences in habitat quality, but also on temporal variation in migration costs. Such variation can, for instance, arise from changes in wind or current velocity for migrating birds and fish, respectively. Whereas behavioural responses of birds to such changing environmental conditions have been relatively well described, this is not the case for fish, although fish migrations are both ecologically and economically important. We here use passive and active telemetry to study how winter migrating roach regulate swimming speed and distance travelled per day in response to variations in head current velocity. Furthermore, we provide theoretical predictions on optimal swimming speeds in head currents and relate these to our empirical results. We show that fish migrate farther on days with low current velocity, but travel at a greater ground speed on days with high current velocity. The latter result agrees with our predictions on optimal swimming speed in head currents, but disagrees with previously reported predictions suggesting that fish ground speed should not change with head current velocity. We suggest that this difference is due to different assumptions on fish swimming energetics. We conclude that fish are able to adjust both swimming speed and timing of swimming activity during migration to changes in head current velocity in order to minimize energy use.     

Haematological disturbances and osmotic shifts in rainbow trout,Oncorhynchus mykiss (Walbaum) under acid and aluminium exposure

Summary Elevated values of haematocrit were observed in rainbow trout (Oncorhynchus mykiss) during combined acid and aluminium exposure. Possible causes of this, i.e., decreased plasma volume, swelling of erythrocytes, and/or mobilization of erythrocytes into the blood were investigated. Slight haematocrit increases (10–20%) during mild acid stress (pH 5.0, 25 mol Ca²⁺·1^-1) were mostly caused by osmotic shifts. Both swelling of erythrocytes rocytes and a significant decrease of the plasma volume were demonstrated in fish at pH 5.0. These osmotic disturbined were greater during acid exposure (pH 5.0) combined with Al (60 g·1^-1; 200 g·1^-1). In addition, numbers of erythrocytes increased by 40% compared to acid exposure, which contributed to the severe haematocrit rise (35%) during Al exposure. A contraction of the spleen releasing erythrocytes into the blood is suggested to occur as an adrenergic response to hypoxia, which is observed in fish acutely exposed to Al.Abbreviations BV blood volume - ECFV extracellular fluid volume - ICFV intracellular fluid volume - ISFV interstitial fluid volume - MCHC mean cell haemoglobin concentration - MCV mean cell volume - PV plasma volume     

Comparative study of some haematological and biochemical blood parameters in fishes from the Skagerrak

Marine fishes caught in the Skagerrak, 27 different species representing various groups of fishes (Cyclostomi, Holocephali, Elasmobranchii and Teleostei), were examined for the following haematological and biochemical blood parameters: haematocrit, haemoglobin, mean corpuscle haemoglobin concentration, total plasma protein, blood glucose and blood lactate. Interspecies variations as well as variations within some species were observed. The haemoglobin values for all species showed a positive correlation to the corresponding haematocrit values. Relatively low values for haematocrit and haemoglobin were found in cyclostomes, holocephaleans and elasmobranchii compared to the majority of teleosts. Within the teleost group, the haematocrit and haemoglobin levels were positively correlated with the activity of the fish species. The cyclostome Myxine glutimsa L. had a total plasma protein content in the same range as most teleosts, whereas holocephaleans, elasmobranchii and the deep-water teleost Coryphaenoides rupestris Gunnerus showed comparatively low values. Among teleosts some relationship seemed to exist between the total plasma protein level and the activity of the fish species. In addition, a correlation between plasma protein content and levels of blood lipids were noted. Values for blood glucose and blood lactate were found to be lower in cyclostomes, holocephaleans and elasmobranchii than in most teleosts. Higher blood glucose levels were observed in the more active teleost species.     

Depth selection behaviour during activity cycles of juvenile plaice on a simulated beach slope

Juvenile plaice Pleuronectes platessa on a sand slope in a laboratory tank showed depthselection behaviour consistent with offshore migration by day and onshore by night, as seen in natural conditions. Plaice stayed deep (0·5 m) and avoided the shallowest water (<10 cm depth) during light periods, but ventured up the slope and into the shallows in darkness. The freshly caught fish showed circatidal cycles of activity, but showed no change in depth selection between periods of high (time of expected high water) and low activity (expected low water). This suggests that changing direction of movements in tidal migration is controlled by responses to changing environmental conditions. Further analysis showed movements of fish up the slope to be slower, covering less distance and with shorter pauses in between than moves down the slope. Frequency, distance travelled and speed of moves up and down the slope did not change with tidal or light-dark cycles, and so such modulation could be ruled out as a mechanism for migration.     

细菌性败血症引起鲫凝血障碍的研究

以嗜水气单胞菌感染体重７０ｇ左右的鲫并检测了感染鱼和对照鱼的血液学及播散性血管内凝血判定指标等参数。结果表明细菌性败血症病鱼严重贫血,存在明显的凝血障碍,在疾病发展过程中存在播散性血管内凝血现象。这一些象导致了病鱼全身性出血,并在疾病的病理生理过程中起了重要作用。     

Effect of endurance flight on haematocrit in migrating birds

The effects of an endurance flight on the haematocrit, the percentage of packed red blood cells per blood volume, were examined within the framework of six possible factors explaining possible changes in the haematocrit. Two approaches were adopted: (1) the haematocrit was studied in four species of passerine birds which landed on an Italian island after having crossed the Mediterranean Sea on their spring migration in a non-stop flight; (2) the haematocrit was evaluated in six individual red knots after a flight of 1, 2, 4 and 10 h in a wind tunnel and the data thus obtained compared with data on resting birds with or without food. In the four passerine species, the haematocrit decreased from 51% in fat birds to 48% in lean birds. In lean birds, the haematocrit dropped from 48% in birds with well-developed breast muscles to 36% in birds with emaciated breast muscles. In the red knots, the haematocrit was dependent on body mass in flying and resting birds. The haematocrit decreased from about 51% pre-flight to about 49% within 1 h of flight and remained at this level for up to 10 h of flight. Taking the results from the passerines and the red knots together, it seems that the haematocrit drops by a few percentage points within 1 h after the onset of flight, decreases very slowly with decreasing body mass and decreases more steeply in very lean birds having entered stage III of fasting. This indicates that dehydration is not an underlying factor in decreased haematocrit because if this were the case we would expect an increase with endurance flight. We found no effect of the presence of blood parasites on haematocrit. With the onset of flight, haemodilution may be adaptive, because it reduces blood viscosity and, thereby, energy expenditure by the heart, or it may be a sign of water conservation as an insurance against the risk of dehydration during long non-stop flights. During endurance flight, a reduction in the haematocrit may be adaptive, in that oxygen delivery capacity is adjusted to the decreased oxygen needs as body mass decreases. A decreasing haematocrit would also allow birds to reduce heart beat frequency and/or heart size, because blood viscosity decreases disproportionally with decreasing haematocrit. However, when energy stores are about to come to an end and birds increase protein breakdown, the haematocrit decreases even further, and birds probably become anaemic due to a reduced erythropoiesis.     

Regulation of splenic contraction persists as a vestigial trait in white-blooded Antarctic fishes

In fishes, the spleen can function as an important reservoir for red blood cells (RBCs), which, following splenic contraction, may be released into the circulation to increase haematocrit during energy-demanding activities. This trait is particularly pronounced in red-blooded Antarctic fishes in which the spleen can sequester a large proportion of RBCs during rest, thereby reducing blood viscosity, which may serve as an adaptation to life in cold environments. In one species, Pagothenia borchgrevinki, it has previously been shown that splenic contraction primarily depends on cholinergic stimulation. The aim of the present study was to investigate the regulation of splenic contraction in five other Antarctic fish species, three red-blooded notothenioids (Dissostichus mawsoni Norman, 1937, Gobionotothen gibberifrons Lönnberg, 1905, Notothenia coriiceps Richardson 1844) and two white-blooded “icefish” (Chaenocephalus aceratus Lönnberg, 1906 and Champsocephalus gunnari Lönnberg, 1905), which lack haemoglobin and RBCs, but nevertheless possess a large spleen. In all species, splenic strips constricted in response to both cholinergic (carbachol) and adrenergic (adrenaline) agonists. Surprisingly, in the two species of icefish, the spleen responded with similar sensitivity to red-blooded species, despite contraction being of little obvious benefit for releasing RBCs into the circulation. Although the icefish lineage lost functional haemoglobin before diversifying over the past 7.8–4.8 millions of years, they retain the capacity to contract the spleen, likely as a vestige inherited from their red-blooded ancestors.     

Macrotidal estuaries: a region of collision between migratory marine animals and tidal power development

Macrotidal estuaries of the inner Bay of Fundy are utilized by large numbers of migratory fishes, particularly dogfish, sturgeon, herring, shad, Atlantic salmon and striped bass as well as by other migratory marine animals, many of which have large body sizes (squid, Lamnid sharks, seals and whales). Tagging experiments indicate the fishes originate from stocks derived over the entire North American Atlantic coast from Florida to Labrador. Population estimates suggest up to 2.0 times 10⁶adult American shad (Alosa sapidissima) migrate through an individual embayment each year. These migrations are an integral part of the life history of the respective species and appear to be controlled in part by the near shore movements of ocean currents. In other regions of the world similar macrotidal estuaries exist (Cook Inlet, Alaska; Severn Estuary, U.K.) and they, like the Bay of Fundy, are linked in continuum to the local ocean currents. We propose that marine animals utilize all these regions in a manner similar to the Bay of Fundy estuaries and properly designed surveys will reveal their presence. Fish passage studies utilizing the Annapolis estuary low-head, tidal turbine on the Bay of Fundy have shown that turbine related mortality of 20–80% per passage occurs depending on fish species, fish size and the efficiency of turbine operation. We suggest that introduction of tidal turbines into open ocean current systems will cause widespread impact on marine populations resulting in significant declines in abundance.     

Treatment of anemia in patients with renal failure using erythropoietin obtained by genetic recombination

In 5 haemodialyzed patients with end-stage renal failure an effect of human recombinant erythropoietin (r-huEpo) on haemoglobin, haematocrit and iron metabolism was studied. After 12 weeks of the treatment, a significant increase in haemoglobin and haematocrit but significant decrease in plasma ferritin were noted. During r-huEpo treatment, one patients presented clinical symptoms of increased blood coagulation whereas another patients an increase in blood pressure. r-huEpo did not influence leukocytes and platelets count as well as liver function tests. Our results suggest, that r-huEpo is highly effective and safe in the treatment of anaemia in patients with chronic uraemia. Iron metabolism, blood pressure and blood coagulation must be monitored during therapy with r-huEpo.     

Temporal variations in haematological and biochemical indices of the Caspian kutum, <Emphasis Type="Italic">Rutilus frisii kutum</Emphasis>

The pattern of haematology and blood biochemistry variations of healthy adult female kutum Rutilus frisii kutum (Cyprinidae) was investigated in the three reproductive states: maturing (autumn), pre-spawning (winter), and spawning (spring). Red blood cells, haemoglobin, and haematocrit were highest in autumn, whereas the highest values for white blood cells, mean corpuscular volume (MCV), and mean corpuscular haemoglobin (MCH) were observed in winter. With the exception of MCV and mean corpuscular haemoglobin concentration (MCHC), fish size had no effect on haematological and biochemical parameters. MCV was higher in larger fish, whereas the reverse trend was found for MCHC. Decreased levels of plasma glucose, cholesterol, and triglyceride in the pre-spawning period, when female ovaries were developing, may have been due to the combination of reproductive effects and food shortage in winter. Total protein levels were lower during the maturing period than during the pre-spawning period. The results of this study suggest that temporal variations in haematological and biochemical parameters of blood are significant and should be considered when these parameters are used to assess fish health status.