Marine biological invasions in waters of the port of Novorossiysk in the Black Sea

The results of the monitoring of ballast waters of commercial vessels and research on the ecosystem biodiversity of the Novorossiysk Port are reported. Data on structure of immigrant fauna, its abundance, survival and origin of species were obtained. It has been established that the risk of introduction of Mediterranean species into the Novorossiysk Bay is the most probable. The basic “risk groups” are copepods and polychaetes. It has been hypothesized, that ship ballast water can become a primary factor of the “mediterranization” of the copepod fauna (Copepoda) in the northeast of the Black Sea. During the period of research in the Novorossiysk Bay, 36 species of Mediterranean copepods were recorded. A massive number of the cyclopoid copepod Oithona brevicornis Giesbr., 1891, a new species for the Black Sea, was recorded in samples collected in the autumn of 2005 and 2006. The status of the invader was attributed to the polychaete of the Streblospio genus. The necessity of ship ballast water control in Russia and the development of methodology, methods, and regulations for the prevention of the intrusion of pathogenic and potentially dangerous organisms by marine traffic were corroborated.     

Short communication. Food availability and diel feeding rhythms in the marine copepods Acartia grani and Centropages typicus

The effects of food availability on the daily feeding pattern of planktonic copepods was studied for two species: Acartia grani (cultured and wild specimens) and Centropages typicus (wild specimens). Both species showed clear diel feeding rhythms at high food concentrations, with significantly higher clearance rates during night hours. However, at limiting food conditions, while C.typicus maintained its daily feeding pattern, A.grani fed continuously, with similar day and night clearance rates. These results could be explained in relation to differences in predation risks and probability of experiencing starvation episodes in their respective habitats, as well as their capacity for dampening food fluctuations. On the other hand, the maintenance (although with less intensity) of the diel feeding rhythm in A.grani, when cultured in the laboratory for long periods of time (>10 generations) and in the absence of predators, suggests the importance of the endogenous control of copepod feeding patterns.      

Competitive advantage of the invasive copepod Oithona davisae over the indigenous copepod Oithona nana in the Marmara Sea and Golden Horn Estuary

Around 2010, the alien copepod Oithona davisae was introduced to the Marmara Sea and Golden Horn Estuary to live alongside the native species, Oithona nana. By October 2015, the population number, including nauplii, of the introduced species (213,600 ind m^?3) was higher than that of the native species (54,900 ind m^?3) and close to that of O. davisae in Sevastopol Bay of the Black Sea (342,000 ind m^?3) where it appeared 14 years ago. A high percentage of O. davisae females with ovisacs (up to 30% of total female number) carrying up to 15.1 ± 2.1 eggs in the sac and the predominance of nauplii in the population (up to 95% of the total population number) indicate that this alien copepod has become a permanent component of the Marmara Sea and Golden Horn Estuary ecosystem. Our experiments showed that in comparison with widely euryhaline O. davisae, O. nana is a stenohaline species. It has a salinity tolerance in the range of 13–27 psu and, in spite of having a larger body, a lower body density (1.037 ± 0.007 g cm^?3) and sinking speed. Carbon-specific respiration rates of both species were close (0.32–0.38 μL O₂ μgC^?1 day^?1) and similar to that of O. davisae from the Black Sea during this period but the frequency and speed of routine jumps, and the maximum escape reaction speed (up to 23.3 ± 1.7 cm s^?1) in O. davisae from the Marmara Sea were significantly higher. This indicates the higher adaptive potential of O. davisae in this situation compared to that of O. nana.     

Influence of steady-state and fluctuating salinities on the oxygen consumption and activity of some brackish water shrimps and fishes

Oxygen consumption, locomotory activity and, in some cases, osmoregulatory responses of different populations of Palaemon adspersus (Rathke) and Pomatoschistus microps (Krøyer) from the Isefjord ($\text{S 19‰}$) and Karrebaek Fjord ($\text{S 12‰}$) in Denmark and the Barther Bodden ($\text{S 6‰}$) in the G.D.R. to short-term salinity fluctuations, and after long-term adaptation, were tested. The same tests were performed on populations of Gasterosteus aculeatus (L.), Palaemonetes varions (Leach) (both from Barther Bodden, G.D.R.) and Palaemon elegans (Rathke) (Black Sea, Bulgaria, $\text{S 18‰}$). The steady-state experiments showed that the standard metabolic rates of P. adspersus and Pomatoschistus microps reach their lowest levels at mean biotope salinities at both 10 and 20°C. In contrast, the routine metabolic rates of both species are independent of salinity in the ecological salinity range.All Palaemon adspersus and Pomatoschistus microps populations responded to sudden changes in salinity with increased locomotory activity and respiration regardless of the direction of stressing. Metabolic adaptation in these euryhaline species, which is not synchronous with osmotic readjustment, takes from 5 to 12 h, depending on the salinity gradient.The polystenohaline Palaemon elegans from the Black Sea and the holeuryhaline Palaemonetes varians from the Barther Bodden exhibit similar short adaptation times (≈ 2 h) to identical salinity gradients but in different salinity zones.     

The use of sheepshead minnow (Cyprinodon variegatus) and a benthic copepod (Tisbe battagliai) in short-term tests for estimating the chronic toxicity of industrial effluents

Summary results of laboratory investigations into potential chronic effects of industrial effluent discharges are presented and discussed. The sheepshead minnow (Cyprinodon variegatus) and the benthic copepod (Tisbe battagliai) were selected as test species. Toxicity tests were conducted on newly hatched (approximately 24 hours old) sheepshead minnow larvae. Survival and growth (as dry weight) effects were measured over 7 days. Two different stages of the copepod life cycle were tested: effects on adult female survival and reproduction were measured over 9 days, and naupliar survival over 7 days. The results were incorporated into an existing monitoring programme of the effluent disposal area in the North Sea. Predicted effluent dilutions in the disposal area would exceed one million times within 8 hours. This dilution is 18 and 100 times greater than the 7 day lowest no observed effect concentration (NOEC) for copepod and sheepshead minnow respectively.     

Day-night behavior in river entry of kutum and its relation to melatonin

Reproduction in most fish species is a scheduled phenomenon and spawning occurs at a precise time ensuring maximum survival of offspring. During the spawning season, reproductive activities of fish species and their daily entry to rivers are influenced by environment. Number of Rutilus frisii kutum entered a river discharging to Caspian Sea was analyzed to investigate the association between timing of river entry and day–night changes in environmental variables. Four thousand five hundred and sixty seven ascending adult kutum were collected in Khoshkrood River between March and May 2012. Physicochemical parameters were recorded and Melatonin levels were measured in a hundred migratory kutum over day and night during the spawning period. A significant effect of daytime on river entry was observed, as more fish entered the river at night. Melatonin levels decreased to the minimum level during peak days of migration, suggesting variations in melatonin levels can help to harmonize the daily rhythm in kutum migration.     

The mortality of the planktonic copepod <Emphasis Type="Italic">Oithona similis</Emphasis> Claus, 1866 (Copepoda: Cyclopoida) in the Barents and White Seas

The mortality rates of the copepodite IV-copepodite V and copepodite V-adult individuals pairs in the populations of one of the most common species of planktonic copepod, Oithona similis, were estimated for the first time in the Barents and White seas. The average parameters were 0.060 and 0.082/day, respectively, in the Barents Sea and 0.166 and 0.120/day in the White Sea. In the Barents Sea, the mortality rates of O. similis significantly increased with an increase in water temperature and in the White Sea a significant decrease occurred with an increase in salinity. It was concluded that the mortality rate of this species is determined first by abiotic factors and that biotic factors are of secondary significance.     

The role of copepods in the planktonic ecosystems of mixed and stratified waters of the European shelf seas

The European shelf seas can be divided into regions which have tidally mixed waters and thermally stratified waters. The tidally mixed near shore environments support zooplankton communities dominated by smaller copepods and having large meroplankton contributions. These small copepods (Centropages spp., Temora spp., Acartia spp., Paral Pseudo/Microcalanus spp.) together with the microzooplankton component form a different and more complex food web than the larger copepod/diatom link associated with thermally stratified waters. The copepods Calanus finmarchicus and C. helgolandicus account for over 90% of the copepod dry weight biomass in stratified waters. Although occurring in lower numbers in mixed waters they can still make significant contributions to the biomass. A 31 year time series from the European shelf shows the inter- and intea-annual variability of these species. The basic biology and food web that these two systems support, and the transfer of energy, can result in marked differences in quantity and quality of particulates available as food for fish larvae. Calanus dominated systems allow the primary production to be directed straight through the trophic food chain (diatoms/Calanus/fish larvae) while the near shore communities of smaller copepods limit the amount of energy being transferred to the higher trophic levels. Eighty-two Longhurst Hardy Plankton Recorder hauls were used as the data base for this study. In all cases the zooplankton was dominated by copepods both in numbers and biomass accounting for > 80% of total zooplankton dry weight in the Irish Sea, Celtic Sea, shelf edge of the Celtic Sea and the northern and southern North Sea in Spring.     

Species composition,distribution, and specific features of feeding of Fish Larvae,and fry in the Sea of Okhotsk from October to December 2007

Ichthyoplankton of the Sea of Okhotsk from October to December 2007 comprised larvae and fry of eight fish species belonging to five families. The larvae of lord Hemilepidotus gilberti, white-spotted greenling Hexagrammos stelleri, and Atka mackerel Pleurogrammus monopterygius were the most widespread and numerous in the study period. Fish larvae from October to December 2007 were seined over the vast water area of the Sea of Okhotsk, maximum catches were made in waters of western Kamchatka. The food spectrum of larvae of five fish species (H. gilberti, Hexagrammos octogrammus, H. stelleri, P. monopterygius, and Bathymaster signatus) included approximately 20 plankters. Irrespective of species belonging, copepods Pseudocalanus minutus and Oithona similis, eggs and nauplii of copepods, as well as juveniles of pteropods were common food items for all fish. Larvae of all considered fish species in the Sea of Okhotsk fed mainly during the light hours of the day.     

The problem of invaders in the Caspian Sea in the context of the findings of new zoo- and phytoplankton species from the Black Sea

In April 2004, an expedition to the Caspian Sea discovered the species in the Middle Caspian not previously described in this sea. These species preliminary identified as Oithona similis Claus 1963, Sagitta setosa Muller 1847, and Calanus euxinus (Hulsemann) are the main representatives of edible plankton of the Black Sea; most likely they were introduced into the Caspian Sea with ballast waters of ships passing through the Volga-Don Canal. At present, it is difficult to say if these species will be established in the Caspian Sea; if so, they will clearly become a valuable food resource for planktophagous fish in the Caspian Sea. In addition, we discovered two diatom species typical for the Black Sea phytoplankton, Pseudo-nitzschia seriata (Cleve) H. Peragallo and M. Peragallo and Cerataulina pelagica (Cleve) Hendey which invaded the Caspian Sea in recent years. Pseudo-nitzschia seriata synthesizes a toxin (domoic acid) and can become harmful for the basin in the case of mass bloom. We discuss the problem of spontaneous invasion of alien species from the Black Sea and their effect on the Caspian ecosystem in the context of these findings.Translated from Izvestiya Akademii Nauk, Seriya Biologicheskaya, No. 1, 2005, pp. 78–87.Original Russian Text Copyright © 2005 by Shiganova, Musaeva, Pautova, Bulgakova.     

Daily rhythm of plasma corticosterone binding activity in the white-throated sparrow,Zonotrichiaalbicollis

There is a bimodal daily rhythm of plasma corticosterone binding activity (CBA) in the white-throated sparrow, $\text{Zonotrichia}$$\text{albicollis}$, in the spring migratory condition. Low levels occurred at the beginning (0500) and at the end (2100) of a 16-hour daily photoperiod. Peak CBA occurred at 0900 and 0100, as did peak locomotor activity in this nocturnal migrant. Comparisons of CBA with total plasma corticosteroid concentrations from a previous study of the same group of birds indicate a positive correlation during most of the day but not during the early hours of darkness. The daily rhythm of locomotor activity may account for the rhythm of CBA which, in turn, may be partially responsible for the daily rhythm of plasma corticosteroid concentration.     

Endogenous rhythmic activity of photosynthesis, transpiration, dark respiration, and carbon dioxide compensation point of peanut leaves

At 14-hour day length, 25 C leaf temperature, 9 mm Hg vapor-pressure deficit, and 1.17 joules cm⁻² min⁻¹ irradiance, the diurnal change in daily photosynthesis of the cultivated peanut (Arachis hypogaea L.) is a result of an endogenously controlled circadian rhythm in net photosynthesis which peaks near noon and troughs near midnight. By resetting the day-night light regime, the rhythm rephased in continuous light. The free-running rhythm approximates 26 hours. Both transpiration and dark respiration show similar rhythmicity, with transpiration closely in phase with the rhythm in photosynthesis. The rhythm in carbon dioxide compensation point is approximately 12 hours out of phase, peaking at midnight and troughing at midday. Endogenous changes in stomatal aperture seemed to be the major control of the rhythm in photosynthesis. The activity of ribulose-1,5-diphosphate carboxylase increased during the normal photoperiod, leveling off after 12 hours; however, the activity was not correlated with the rhythmic change in photosynthesis.     

Effects of food deprivation and type of prey on predation by Notiophilus biguttatus F. (Carabidae) on springtails (Collembola)

Summary With diurnally active predators like Notiophilus biquttatus F. food deprivation is involved in predation in two ways: as a consequence of food shortage (i.e., low prey density), and as a consequence of the night period. The pattern of food intake after deprivation at night has been studied with respect to two prey species and differently deprived predators. They prey species represent a locomotory active one (Orchesella cincta) and a locomotory inactive one (Tomocerus minor). It appears that the rate of predation after deprivation shows a distinct pattern, initially high and then slowing to a more or less constant value. This pattern is influenced by food deprivation and type of prey. The beetles preying on O. cincta consumed more prey than those preying on T. minor. The more deprived predators compensated for deprivation by a higher daily predation when O. cincta was the prey, but not when T. minor was. Consequences of these findings are discussed with respect to diet composition and functional response.     

Photoperiodically regulated cycle of locomotory activity and fat reserves during migration seasons in the irruptive bird species,the long‐tailed tit Aegithalos c. caudatus

In northern Europe the long‐tailed tit Aegithalos c. caudatus shows irregular outbreaks of migrating individuals in autumn. Therefore, this species is generally believed to be irruptive, moving in response to external environmental stimuli such as food limitation or overpopulation in the breeding area. We studied the locomotory activity of 24 young captive long‐tailed tits from August up to early May of the following year. All hand raised birds from the local population of Lake Ladoga region (NW Russia) exhibited a distinct seasonal pattern in their locomotory activity similar to birds trapped on migration. They showed a rise in activity both in autumn and spring period. Fat reserves did not peak in autumn but increased along with spring activity. The timing of increase in the locomotory activity and fat reserves, as well as daily pattern and maximum level of activity in autumn depended on photoperiod. Long‐tailed tits kept on the photoperiod, simulating late hatching, started to migrate at an earlier age and showed a significantly higher level of activity in autumn compared to their siblings kept on the photoperiod simulating early hatching. The present findings suggested that in the studied species there is an annual cycle of migratory restlessness that is exhibited in captivity and is influenced by photoperiod.     

The ctenophore Mnemiopsis in native and exotic habitats: U.S. estuaries versus the Black Sea basin

The native habitats of the ctenophore, Mnemiopsis, are temperate to subtropical estuaries along the Atlantic coast of North and South America, where it is found in an extremely wide range of environmental conditions (winter low and summer high temperatures of 2 and 32 °C, respectively, and salinities of <2–38). In the early 1980s, it was accidentally introduced to the Black Sea, where it flourished and expanded into the Azov, Marmara, Mediterranean and Caspian Seas. We compile data showing that Mnemiopsis has high potentials of growth, reproduction and feeding that enable this species to be a predominant zooplanktivore in a wide variety of habitats; review the population distributions and dynamics of Mnemiopsis in U.S. waters and in the Black Sea region; and examine the effects of temperature and salinity, zooplankton availability and predator abundance on Mnemiopsis population size in both regions, and the effects of Mnemiopsis on zooplankton, ichthyoplankton and fish populations, focusing on Chesapeake Bay and the Black Sea. In both regions, Mnemiopsis populations are restricted by low winter temperatures (<2 °C). In native habitats, predators of Mnemiopsis often limit their populations, and zooplanktivorous fish are abundant and may compete with the ctenophores for food. By contrast, in the Black Sea region, no obvious predators of Mnemiopsis were present during the decade following introduction when the ctenophore populations flourished. Additionally, zooplanktivorous fish populations had been severely reduced by over fishing prior to the ctenophore outbreak. Thus, small populations of potential predators and competitors for food enabled Mnemiopsis populations to swell in the new habitats. In Chesapeake Bay, Mnemiopsis consumes substantial proportions of zooplankton daily, but may only noticeably reduce zooplankton populations when predators of Mnemiopsis are uncommon. Mnemiopsis also is an important predator of fish eggs in both locations. In the Black Sea, reductions in zooplankton, ichthyoplankton and zooplanktivorous fish populations have been attributed to Mnemiopsis. We conclude that the enormous impact of Mnemiopsis on the Black Sea ecosystem occurred because of the shortage of predators and competitors in the late 1980s and early 1990s. The appearance of the ctenophore, Beroe ovata, may promote the recovery of the Black Sea ecosystem from the effects of the Mnemiopsis invasion.     

Annual changes in the population size of the salmon louse Lepeophtheirus salmonis (Copepoda: Caligidae) on high-seas Pacific Salmon (Oncorhynchus spp.), and relationship to host abundance

The population size of the salmon louse, Lepeophtheirus salmonis, was monitored annually in the summers of 1991–1997 by examining six species of Pacific salmon (Oncorhynchus spp.) caught by surface long-lines in oceanic offshore waters of the North Pacific Ocean and Bering Sea. The annual copepod population size on all salmonids caught was estimated by combining the calculated number of copepods carrying on each salmonid species. The copepod population fluctuated markedly from year to year, which resulted largely from marked annual changes in abundance of pink salmon (O. gorbuscha). Since pink salmon were most frequently and heavily infected and since their abundance changed every year, the copepod population was high in the years when this salmonid species was abundant, but low when it was rare. On the contrary, chum salmon (O. keta) did not show high prevalence and intensity of infection, but the annual abundance of this host species was consistently high, i.e. chum salmon carried many copepods every year. Copepods on other salmonid species (sockeye salmon O. nerka, coho salmon O. kisutch, chinook salmon O. tshawytscha, and steelhead trout O. mykiss) constantly formed a small percentage of the total copepod population. Both chum and pink salmon are the most important hosts in terms of their substantial contribution to support the copepod population, but the importance as hosts of each species is definitely different between the species. Chum salmon is a stable important host supporting the copepod population at a relatively high level every year, while the number of copepods on pink salmon annually exhibits marked fluctuations, and this salmonid species is regarded as an unstable important host.     

Metabolic costs of the predation strategy of the spider Pardosa amentata (Clerck) (Lycosidae)

Summary Pardosa amentata adopts a sit-and-wait predation strategy with periodic changes of site. The metabolic costs of this strategy were evaluated using a Gilson respirometer. The respirometer was run at the mean temperatures prevailing month by month in the litter layer from which the experimental animals were collected and equations relating standard respiration rate to spider weight were established for each temperature. The mean value of b, the exponent relating weight to respiration rate, was 0.8011. Active respiration rate was determined at each temperature by using larger experimental flasks containing small glass beads which, in conjunction with the shaker mechanism on the respirometer, ensured that the spiders in the respirometer flasks maintained a fairly consistent level of locomotory activity. It was found that the measured active respiration rate was on average 3.17 times the standard rate. The two respiration rates were combined in the appropriate proportions to calculate the daily energy expenditure of an adult spider exhibiting its normal pattern of activity at different temperatures. It is shown that as locomotory activity is very limited in duration in P. amentata, the associated active respiration rate accounts for only a small proportion of daily respiratory energy losses, 0.36% at 5°C, 0.69% at 10°C, and 1.01% at 15°C.     

Circadian locomotor rhythm masked by the female reproduction cycle in cockroaches

Blattella bisignata (Brunner) and B. germanica (L.) are oviparous cockroaches with cyclic reproductive behaviour, but in B. germanica only males show circadian rhythmicity of locomotion at 28°C and DD (constant darkness). In B. bisignata, males and virgin females cockroaches entrained by light–dark cycles show free‐running rhythmicity in DD, and most activities occur during the subjective night. Daily locomotor activities of virgin females show cyclic changes that coincided with ovarian development. Virgin females also exhibit calling behaviour during the subjective night, and this shows a free‐running rhythm. Male mate‐finding locomotion and female calling behaviour are under circadian control, so the timing for both behaviours is synchronized. However, most mated females do not show a locomotor free‐running rhythm under DD conditions. Our results indicate that only mated females could not express a circadian locomotor rhythm. Pregnancy reduces a female’s locomotory intensity and masks the expression of a circadian locomotor rhythm. We attribute the differences in circadian locomotory rhythms between these two species to their living environments and mate‐finding strategies.     

Populations of the red tide forming dinoflagellate Noctiluca scintillans (Macartney): A comparison between the Black Sea and the northern Adriatic Sea

Populations of Noctiluca scintillans (hereafter Noctiluca) were compared from two regions: the northeastern-central Black Sea and the northern Adriatic Sea. In both seas samples were collected in near-shore waters 2–3 times per month during 2004–2012. For analysis of feeding activities and seasonal dynamics additional cruise data on the open waters of the Black Sea were used. Comparison between the two populations shows similarity in size structure with two classes 401–500 μm and 501–600 μm being the most numerous. Seasonal changes in cell abundance in both seas demonstrated a regular annual maximum with the peak period of high abundances in May–June with additional sporadic peaks in other seasons. In spring the average number of food vacuoles in the cell (1.78) and the proportion of feeding cells in populations (79%) in the Adriatic Sea were similar to those in the Black Sea (1.58 and 76%). In September–October, these parameters were lower both in the Adriatic Sea (0.69 and 49%) and in the Black Sea (1.46 and 65%) demonstrating that Noctiluca was better provided with food in spring. Among biotic parameters (wet phytoplankton biomass, chlorophyll biomass and zooplankton species) only the concentration of the eggs of Calanus euxinus was significantly positively correlated with abundance of Noctiluca. The possible effect of a high concentration of copepod eggs on the growth of Noctiluca in the peak period is discussed. An obvious negative relationship was observed between Noctiluca cell numbers in the peak period and wind velocity in both seas. The most significant negative correlation was observed between the number of windy hours per month (velocity more than 5–6 m s⁻¹) and cell concentrations in the Black Sea (r = −0.92) and in the northern Adriatic Sea (r = −0.67). On this basis, a new hypothesis has been proposed and discussed: in connection with features of the food behavior of Noctiluca, its outbursts during the peak period are controlled by the wind. An evident positive relationship was observed between the number of Noctiluca in the peak period and its quantity in the preceding months in both seas. Thus, we suggest that abundance data during early spring and weather forecasts (winds) may be used for medium-term prediction of Noctiluca outbursts and red tides.     

Influence of food density on respiration rate of two crustacean plankters,Daphnia galeata and Bosmina longirostris

Summary The influence of food density on respiration rate was measured for two cladoceran plankton species, Daphnia galeata and Bosmina longirostris, over the range 0 to 2.5 mg C 1^-1, using the modified Winkler technique in order to examine how this affects the respiration rate and whether the functional response is the same in the two species. The respiration rate for animals of equivalent body size did not differ significantly between the two species in the absence of food, but was significantly lower in Bosmina longirostris than Daphnia galeata at high food density. Within a species, the response of respiration rate to changing food density did not differ among individuals of different body size. The respiration rate of D. galeata increased with increasing food density and reached a plateau at a high food density. A similar response curve was also found with the respiration rate of B. longirostris, although the response was less conspicuous. This response curve cannot be explained by the energy cost of known feeding behavior in cladocerans. Since the respiration rate related linearly with the assimilation rate, increase in food density seemed to increase the respiration rate by increasing the energetic cost required to process food biochemically, known as specific dynamic action.