Respiratory and osmoregulatory responses of the hermit crab, Clibanarius vittatus (Bosc), to salinity changes

Intertidal hermit crabs were stepwise acclimated to 10, 20, and 30‰ salinity (S) and 21 ± 1 °C. Hemolymph osmolality, sodium, chloride, and magnesium were isosmotic (isoionic) to ambient sea water at 30‰ and hyperosmotic (hyperionic) at 20 and 10‰ S, while hemolymph potassium was significantly hyperionic in all acclimation salinities. Total body water did not differ significantly at any acclimation salinity. Oxygen uptake rates were higher in summer-than winter-adapted crabs. No salinity effect on oxygen consumption occurred in winter-adapted individuals. Summer-adapted, 30‰ acclimated crabs had a significantly lower oxygen consumption rate than those acclimated 10 and 20‰ S. Crabs exposed to 30 10 30‰ and 10 30 10‰ semidiurnal (12 h) and diurnal (24.8 h) fluctuating salinity regimes showed variable osmoregulatory and respiratory responses. Hemolymph osmolality followed the osmolality of the fluctuating ambient sea water in all cases, but was regulated hyperosmotically. Hemolymph sodium, chloride, and magnesium concentrations were similar to hemolymph osmolality changes. Sodium levels fluctuated the least. Hemolymph potassium was regulated hyperionically during all fluctuation patters, but corresponded to sea water potassium only under diurnal conditions. The osmoregulatory ability of Clibanarius vittatus (Bosc) resembles that reported for several euryhaline brachyuran species. The time course of normalized oxygen consumption rate changed inversely with salinity under semidiurnal and diurnal 10 30 10‰ S fluctuations. Patterns of 30 10 30‰ S cycles had no effect on oxygen consumption rate time course changes. The average hourly oxygen consumption rates during both semidiurnal fluctuations were significantly lower than respective control rates, but no statistical difference was observed under diurnal conditions.     

Influence of salinity and cadmium on the survival and osmoregulation of Callianassa kraussi and Chiromantes eulimene (Crustacea: Decapoda)

This study investigated the influence of salinity and cadmium on the survival and osmoregulatory capability of two decapod crustaceans, Callianassa kraussi and Chiromantes eulimene. Callianassa kraussi was able to survive in salinities of 5–55 over 96 h, whilst C. eulimene survived in 0–55 over the same time period. The 96-hour cadmium LC₅₀ for both species decreased progressively at salinities above and below their respective isosmotic conditions, with the decrease being slightly more pronounced below compared to above isosmotic salinity. A hypo-iso-osmoregulatory strategy was followed by C. kraussi as it hyper-osmoregulated at salinities between 5 and 25 and osmoconformed at salinities greater than 25. Chiromantes eulimene followed a hyper-hypo-osmoregulatory strategy; it hyper-regulated in salinities from 0 up to isosmotic conditions at about 28 (c. 780 mOsm kg^?1), followed by hypo-regulation up to 55. The effect of cadmium exposure on the osmoregulatory capacity of C. kraussi was more pronounced at hyper-regulating salinities (5–25) whilst on C. eulimene the influence was more pronounced at salinities above the isosmotic point (28). The influence of salinity and cadmium on both survival and osmoregulation of the two crustaceans are discussed by outlining the chemical and physiological mechanisms involved.     

Effect of salinity on the osmotic,chloride, total protein and calcium concentrations in the hemolymph of the prawn Peneaus monodon (fabricius)

• 1.1. Osmolality and chloride concentrations in the hemolymph of Penaeus monodon became stable 1 day after molting in 32 ppt, while total protein and calcium concentrations remained stable throughout the molting cycle. When intermolt (≥ 36 hr postmolt) animals were transferred from control (32 ppt) to experimental (8–40 ppt) salinities, osmolality, chloride and total protein, but not calcium, concentrations in the hemolymph achieved steady state values 24–48 hr after transfer.
• 2.2. The hemolymph osmolality was a linear function (slope = 0.28) of medium osmolality at salinities between 8 and 40 ppt. It was isosmotic to seawater at 698 mOsm (10 g prawns) and 752 mOsm (30 g), and was hyperosmotic to the medium below isosmotic concentrations, and hypoosmotic to those above.
• 3.3. Hemolymph chloride concentration was isoionic to seawater at 334 mM, and was hyperregulated below isoionic concentrations, and hyporegulated to those above.
• 4.4. P. monodon maintained its hemolymph calcium concentration between 6.4 and 10 mM when medium salinities increased from 8 to 40 ppt.
• 5.5. Total protein concentration in the hemolymph was independent of medium salinity (8–40 ppt) and hemolymph osmolality (540–850 mOsm).

     

Effects of salinity and temperature on oxygen consumption in a freshwater population of Palaemonetes antennarius (Crustacea,decapoda)

• 1.1. After step-like increases in salinity the shrimps exhibit the smallest increase in oxygen consumption in the lower salinity range. At higher salinities the shrimps show longer recovery times and greater increases in the metabolic rate after salinity shock.
• 2.2. In steady-state experiments, the shrimps display the lowest oxygen consumption rates near the isosmotic point. The lowest metabolic rates occur at salinities of 3‰ and 10‰ At salinities of 20‰ and above the rate of metabolism increases by 20–30%.
• 3.3. The calculated osmoregulatory work for animals in fresh water amounts to only 2.7% of routine metabolism and drops to 1.1% for shrimps in 3‰ and 0.7% in 5‰ salinity.
• 4.4. Locomotory activity in the form of position change was not responsible for the increased oxygen consumption of the animals after salinity shocks. A “tentative swimming activity” by fast and frequent beating of the pleopods without position change may be an important factor in the increase of metabolic rates.
• 5.5. In its temperature response, the brackish water population has a higher metabolic rate than the freshwater one. Between 5 and 35°C Q ₁₀-values range from 4.01 to 1.37.

     

Osmotic and ionic regulation in Callianassa kraussi Stebbing (Crustacea: Decapoda: Thalassinidea)

Callianassa kraussi Stebbing in southern Africa has been recorded in salinities down to 1‰ Experiments suggest that because of the burrowing activities of the prawns, the substratum is unlikely to provide insulation against transient low surface salinities. Investigation of osmotic and ionic regulation in this species has shown that hyper-osmoregulation occurs in salinities below $\text{\$}\text{?}$20 ‰: hyper-osmoregulatory ability decreases in salinities below $\text{\$}\text{?}$3.5 ‰ Previous work on the genus Callianassa suggested that there was no osmo-regulatory ability in this group and a possible reason for the development of this faculty in the southern African species is discussed.     

Salinity tolerance of adult and juvenile red king crabs Paralithodes camtschatica

• 1.1. Juvenile king crabs were more tolerant of reduced salinities than adult crab; juvenile crab were better volume regulators at reduced salinities than adult crab.
• 2.2. Adult female king crab hemolymph was hyperosmotic to full seawater (30 ppt) and isosmotic to dilute seawater. Juvenile king crab (2 years old) were hypoosmotic at the same concentrations.
• 3.3. Lower osmotic concentration of juvenile hemolymph is at least partially due to lower sodium concentration.
• 4.4. Juvenile king crab can tolerate some dilution and survive for short periods in the reduced salinity of the lower intertidal zone.

     

Acute Toxicity of Arsenic under Different Temperatures and Salinity Conditions on the White Shrimp Litopenaeus vannamei

The aim of this study was to determine acute toxicity in the post larvae of the white shrimp Litopenaeus vannamei after 96 h of exposure to dissolved arsenic under three different temperatures and salinity conditions. Recent reports have shown an increase in the presence of this metalloid in coastal waters, estuaries, and lagoons along the Mexican coast. The white shrimp stands out for its adaptability to temperature and salinity changes and for being the main product for many commercial fisheries; it has the highest volume of oceanic capture and production in Mexican shrimp farms. Lethal concentrations (LC₅₀–96 h) were obtained at nine different combinations (3?×?3 combinations in total) of temperature (20, 25, and 30 °C) and salinity (17, 25, and 33) showing mean LC₅₀–96 h values (±standard error) of 9.13?±?0.76, 9.17?±?0.56, and 6.23?±?0.57 mgAs?L^?1(at 20 °C and 17, 25, and 33 salinity); 12.29?±?2.09, 8.70?±?0.82, and 8.03?±?0.59 mgAs?L^?1 (at 25 °C and 17, 25, and 33 salinity); and 7.84?±?1.30, 8.49?±?1.40, and 7.54?±?0.51 mgAs?L^?1 (at 30 °C and 17, 25, and 33 salinity), respectively. No significant differences were observed for the optimal temperature and isosmotic point of maintenance (25 °C–S 25) for the species, with respect to the other experimental conditions tested, except for at 20 °C–S 33, which was the most toxic. Toxicity under 20 °C–S 33 conditions was also higher than 25 °C–S 17 and 20 °C (S 17 or 25). The least toxic condition was 25 °C–S 17. All this suggests that the toxic effect of arsenic is not affected by temperature changes; it depends on the osmoregulatory pattern developed by the shrimp, either hyperosmotic at low salinity or hiposmotic at high salinity, as observed at least on the extreme salinity conditions here tested (17 and 33). However, further studies testing salinities near the isosmotic point (between 20 and 30 salinities) are needed to clarify these mechanisms.     

Changes in plasma osmolality and Na+/K+ ATPase activity of juvenile obscure puffer Takifugu obscurus following salinity challenge

The osmoregulatory capabilities of 6-month-old juvenile obscure puffer Takifugu obscurus, transferred directly from fresh water to different salinities (0‰, freshwater control; 10‰; 20‰ and 30‰), were studied over an 8-day period. After transfer, plasma osmolality of the fish at 30‰ was significantly higher than those at all other salinities throughout the experiment. The Na⁺/K⁺ ATPase activity in the gills of the fish treated with various salinities increased significantly, peaking at 48 h, then decreased gradually to the control level at 192 h. Similar fluctuation trends of the Na⁺/K⁺ ATPase activity were observed in the kidneys. Modified Gaussian model provided accurate fits for the time-course changes in the Na⁺/K⁺ ATPase activities after abrupt salinity challenge. The results demonstrated that obscure puffer has strong capacity to tolerate abrupt salinity changes and can osmoregulate well over a wide range of salinities even in juvenile stage.     

Energetics of the muricid gastropod Thais (Nucella) lapillus (L.)

Multivariate analysis of the physiological energetics of Thais (Nucella) lapillus (L.) was used to predict combinations of salinity and temperature at which scope for growth and reproduction will be positive. The scope for growth correlated positively with change in energy content at 15 and 20°C. The results suggest that energetic constraints set limits to capacity adaptation at ≈ 22‰ salinity, in agreement with field observations of the species distribution limit within estuaries. The zone of resistance adaptation is limited to salinities 15‰, probably because of an inefficiency in volume regulation at lower salinities. Growth of these dogwhelks is suppressed at minimum winter (5°C) and maximum summer (20°C) temperature, largely due to suppression of feeding. Constraints imposed by physiological energetics are important for an understanding of the ecology of this species, and may explain some features of seasonal change in behaviour, e.g. aggregations for purposes of egg-laying in the winter.     

Distribution ofVibrio cholerae in two Florida estuaries

The distribution ofVibrio cholerae was examined in 2 Florida estuaries, Apalachicola and Tampa Bay.Vibrio cholerae serotype non-01 was the most abundant serotype, being isolated from 45% of the oyster samples, 30% of the sediments, 50% of the waters, and 75% of the blue crabs.Vibrio cholerae serotype 01 was isolated from only one oyster sample. Strong linear correlations betweenV. cholerae and temperature, salinity, or the other physical/chemical parameters measured,Escherichia coli, or fecal coliforms were not observed, but a range of temperatures and salinities appeared relevant to the distribution of the organism. The organism was present in the highest concentrations when salinities were 10‰–25‰ and temperatures were 20?C–35?C.In vitro growth curves of 95V. cholerae environmental isolates further supported that 10‰–25‰ was an ideal salinity range for the organisms. The results suggest thatV. cholerae is a widely distributed organism in the nutrient-rich warm waters of the Gulf Coast estuaries.     

Passive immunization of the tiger prawn, Penaeus monodon, using rabbit antisera to Vibrio harveyi

Passive immunization, toxicity neutralization and the persistence of passive protection in the tiger prawn ( Penaeus monodon ) were investigated using rabbit antisera to the formalinized extracellular products (ECP) (RαECP) and/or formalinized bacterial cells (RαBC) of luminescent Vibrio harveyi strain 820514 originally isolated from diseased tiger prawns. Rabbit antiserum to bovine serum albumin (RαBSA) or phosphate-buffered saline (PBS, pH 7·2) both served as controls. The toxicity of ECP to prawns was neutralized by pre-incubation with RαECP. Passive immunization by pre-injection of RαBC or RαECP into prawns 3 d in advance protected against a lethal dose challenge of bacteria. To determine the persistence of passive protection by rabbit antiserum in tiger prawns, the RαBC, RαECP, RαBSA or PBS were injected into prawns. At 10, 17 or 24 d post-immunization, groups of prawns were given a lethal dose challenge of bacteria. The prawns in the two control groups were all killed within the first 2 d following challenge at all three challenge dates, Pre-injection with RαBC and RαECP provided total protection for 10 and 17 d, respectively, with all treated prawns surviving for at least 2 weeks post-challenge. This is the first study using mammalian antisera to investigate toxicity neutralization, passive immunization and persistence of passive protection by rabbit antisera in prawns. The results could be useful in future studies on virulence mechanisms and disease control of vibriosis in cultured prawns.     

Salinity tolerance and osmoregulatory ability of Galaxias maculatus (Jenyns) (Pisces, Salmoniformes, Galaxiidae)

The salinity tolerance and osmoregulatory ability of Galaxias maculatus were investigated. In the field this species has been recorded from salinities of less than 1‰ to 49‰. In the laboratory, upper L.D.⁵⁰ salinity values of 62‰ after gradual acclimation and 45‰ after direct transfer were established. Within the salinity range of its field occurrence the species is a powerful osmoregulator, being able both to hypo- and hyper-osmoregulate.     

Interaction of salinity and temperature as a mechanism for spatial separation of three co-existing species of Ambassidae (Cuvier) (Teleostei) in estuaries on the south-east coast of Africa

Ambassidae are represented in South African estuaries by three species which are very similar in external morphology, feeding ecology, alimentary system and distribution. The co-existence and spatial separation of these species of Ambassis in the estuaries of southern Africa can be explained by the tolerance of each to salinity and temperature. Investigations of the temperature tolerance ranges of the three species suggest that the osmoregulatory capability of Ambassis productus in reduced salinities (<10%) increases while that of A. gymnocephalus decreases sharply in salinities below 20%. A. natalensis , which is endemic to the south-east coast of Africa, is adapted to a wide range of estuarine conditions. Interaction between salinity and temperature tolerances on the limits within which Ambassis spp. survive is significant with regard to the distribution of the three species in estuaries. Catch data showed that A. productus is restricted to areas of low salinity and seasonal low temperature (upper reaches of estuaries), A. gynmocephalus to high salinities >25% (estuary mouths) and A. natalensis to intermediate salinities associated with the middle reaches of estuaries.     

Effect of cadmium on survival,osmoregulation and gill structure of the Sunda prawn,Macrobrachium sintangense (de Man), at different salinities

The prawn Macrobrachium sintangense is likely to be subjected to occasional exposure to combined metal and saline stressors in its natural environment. This research evaluated the acute toxicity (96?h LC₅₀) of cadmium (Cd) on the prawn M. sintangense, with respect to the osmoregulatory capacity (OC) of prawns and to document histological changes in the gills after exposure to sublethal Cd concentrations at different salinities. The 96?h LC₅₀ of Cd to M. sintangense decreased with increasing salinity. The 96?h LC₅₀ values were 89.12 (72.53–109.50), 681.26 (554.20–837.46) and 825.37 (676.99–1006.27) μg CdL^?1 at 0, 10 and 20 ppt, respectively. The OC of prawns exposed to 30?μg?CdL^?1 at 0 ppt and to 300?μg?CdL^?1 at10 ppt decreased significantly compared with that of control prawns exposed to 0 and 10 ppt respectively. Swelling, hyperplasia and necrosis of gill lamellae resulting in the loss of marginal canals were observed in the gills of prawns exposed to 30?μg?CdL^?1 at 0 ppt and to 300?μg?CdL^?1 at 10 ppt for 7?days.     

The rise in inosine monophosphate and l-lactate concentrations in muscle of live penaeid prawns (Penaeus japonicus,Penaeus monodon) stressed by storage out of water

• 1.1. This work aimed to establish why some species of prawns survived longer than others during simulated commercial shipment.
• 2.2. Metabolism of kuruma prawns, Penaeus japonicus, and black tiger prawns, P. monodon, stored for up to 24 hr in dry sawdust was studied by measuring concentrations of l-lactate, adenylate nucleotides and inosine monophosphate (IMP) in abdominal muscle.
• 3.3. When P. japonicus was stored in sawdust at 12°C the adenylate energy charge (AEC) did not fall and no lactate or IMP accumulated after 24 hr. However, the AEC fell in P. monodon stored at a temperature of 12°C and in P. japonicus stored at higher temperatures. When AEC fell below 0.5–0.6 there was an increase in muscle lactate and IMP concentration.
• 4.4. The results show that high concentrations of lactate and IMP in muscle tissue, at a given temperature, can be used to demonstrate that a prawn has been out of water for too long.

     

Southern oscillation and the northern australian prawn catch

Associations are established between the southern oscillation index (SOI) and penaeid prawn catches within the northern Australian prawn fishery. Analysis involved calculation of correlations between Gulf of Carpentaria banana prawn andtiger prawn catches and Troup’s SOI. Significant positive correlations are observed between catch size and SOI for specific months from pre-wet to post-wet seasons. For banana prawns, the results indirectly confirm some earlier observations of increased catches in conjunction with high rainfall during the onset of monsoon periods, but also indicate an association with late rains. However, the relationship with tiger prawns appears to be in the opposite direction, showing negative correlations with SOI for particular months. Some hypotheses are suggested to explain these results in terms of environmental effects on spawning populations, and comment is made on the potential for forecasting catch sizes. Received: 17 August 1998 / Accepted: 23 June 1999     

O2 consumption and acute salinity exposure in the freshwater shrimp Macrobrachium olfersii (Wiegmann) (Crustacea:Decapoda): whole animal and tissue respiration

The time course of O₂ consumption after acute salinity exposure (1, 3, 6, 12, and 24 h to 0, 7, 14, 21, 28, and 35 S) was examined in isolated supraesophageal ganglia, gills, and intact Macrobrachium olfersii (Wiegmann), a hyperosmoregulating freshwater palaemonid shrimp, to establish patterns of metabolic adjustment during salinity adaptation. In whole shrimps, O₂ uptake rates decline with salinity increase to 21 S, subsequently increasing with further salinity increase. The rates increase to maxima after 6–12-h exposure in low salinities, decreasing steadily with time in high salinities. In gill preparations, O₂ consumption rates increase to a maximum in 14 S, then decline; they are maximal after 3–6-h exposure to low salinities and diminish with time in high salinities. In the supraesophageal ganglion, rates of O₂ uptake, always measured in seawater of 18 S, are also maximal when shrimps are exposed to 14 S, subsequently declining or levelling off. Rates decrease with time in shrimps exposed to very low salinities, and are stable in 21 S, reaching maxima after 3–6-h exposure of shrimps to all other media. Both tissues thus exhibit characteristic response patterns of O₂ consumption rate which appear to depend on their functional significance within the context of the whole organism. Such data are interpreted to indicate an interrelationship between O₂ consumption and osmoregulatory capability.     

The physiological ecology of the supratidal amphipod Talorchestia longicornis

Physiology, behavior, habitat, and morphology are used to determine the degree of adaptation to life on land for amphipod species and systemization within the four functional groups of the family talitridae. Talorchestia longicornis is a semi-terrestrial amphipod found in the supratidal zone of estuaries. The present study investigates the physiological adaptations of this species to life on land through measurements of osmoregulation and respiration. Over the salinity range of 1-40‰, T. longicornis regulated its hemolymph hyperosmotically at low salinities and hypoosmotically at high salinities. The isosmotic point was about 27‰. Analogously, hemolymph chloride levels were well regulated being hyperionic at low salinities and hypoionic at high salinities. This species is capable of respiration in both air and water. Slopes (b values) of the relationship between weight and oxygen uptake rates ranged from 0.316 to 0.590. Oxygen uptake rates were higher in air than water and at night versus day. Q₁₀ values were slightly below 2.0 for respiration in air for amphipods, irrespective of weight. These physiological adaptations, along with its behaviors, habitat, and morphology, place T. longicornis within the Group III sandhoppers of the Talitridae.     

Effect of sudden change in potassium concentration on <Emphasis Type="Italic">Penaeus latisulcatus</Emphasis> Kishinouye survival,osmolality and health in inland saline water cultures

The aim of the project was to determine the effects of sudden change in potassium concentration in inland saline water on the survival, osmolality and condition indices of western Australian King Prawn—Penaeus latisulcatus Kishinouye. Australia has large volumes of inland saline water that could be used for aquaculture but is often deficient in K⁺. Western king prawn is a candidate species for culture in inland saline water. Such waters require K⁺ fortification for prawn survival and growth. Trials were conducted in tanks to determine the effect of sudden change in K⁺ concentration in inland saline water samples on the survival, osmolality and condition indices of western king prawns. Prawns in tanks were acclimated to inland saline water procured from Wannamal—an inland location in Western Australia. After 3 days of acclimation, prawns were subjected to sudden increase in medium K⁺ concentration over 1 h, ranging from 80% to 100% of the marine water K⁺ concentration by adding potassium chloride. Identical inland saline water was added to the control tanks over the same time period. Survival, ingestion rate and osmoregulatory capacity (OC) were then recorded over 19 days. At the conclusion of the trial, survival ranged from 71% to 78% in the potassium-enriched tanks whereas 100% mortality was observed in the control tanks by day 11. Ingestion rate of prawns was significantly higher in the experimental tanks than in the control. Osmoregulatory capacity of potassium-enriched prawns was significantly lower post- than pre-ionic change and significantly higher at the conclusion of the trial than both pre- and post-ionic change. There was no significant difference in OC between water types at any time period. These results indicate that prawns can tolerate sudden increase in K⁺ content in inland saline water and the higher K⁺ concentration increases survival and OC, but other measures indicate the prawns were experiencing stressful conditions. Guest Editors: J. John & B. Timms Salt Lake Research: Biodiversity and Conservation—Selected Papers from the 9th Conference of the International Society for Salt Lake Research