Dawn counts of spotted shags (Phalacrocorax punctatus) at Tata Beach, Golden Bay, 2009–2018

Unlike resident bird species, the population sizes of migratory species can be influenced by conditions in more than one part of the world. Changes in the numbers of migrant birds, either long‐term or year‐to‐year, may be caused by changes in conditions in the breeding or wintering areas or both. The strongest driver of numerical change is provided in whichever area the per capita effects of adverse factors on survival or fecundity are greatest. Examples are given of some species whose numbers have changed in association with conditions in breeding areas, and of others whose numbers have changed in association with conditions in wintering areas. In a few such species, the effects of potential limiting factors have been confirmed locally by experiment. In theory, population sizes might also be limited by severe competition at restricted stopover sites, where bird densities are often high and food supplies heavily depleted, but (with one striking exception) the evidence is as yet no more than suggestive. In some species, habitats occupied in wintering and migration areas, and their associated food supplies, can influence the body condition, migration dates and subsequent breeding success of migrants. Body reserves accumulated in spring by large waterfowl serve for migration and for subsequent breeding, and females with the largest reserves are most likely to produce young. Hence, the conditions experienced by individuals in winter in one region can affect their subsequent breeding success in another region. Such effects are apparent at the level of the individual and at the level of the population. Similarly, the numbers of young produced in one region could, through density‐dependent processes, affect subsequent overall mortality in another region. Events in breeding, migration and wintering areas are thus interlinked in their effects on bird numbers. Although in the last 30–40 years the numbers of some tropical wintering birds have declined in western Europe and others in eastern North America, the causes seem to differ. In Europe, declines have mainly involved species that winter in the arid savannas of tropical Africa, which have suffered from the effects of drought and increasing desertification. In several species, annual fluctuations in numbers and adult survival rates were correlated with annual fluctuations in rainfall, and by implication in winter food supplies. In North America, by contrast, numerical declines have affected many species that breed and winter in forest, especially those eastern species favouring the forest interior. Declines have been attributed ultimately to human‐induced changes in the breeding range, particularly forest fragmentation, which have led to increases in the densities of nest predators and parasitic cowbirds. These in turn are thought to have caused declines in the breeding success of some neotropical migrants, which is now too low to offset the usual adult mortality, but as yet convincing evidence is available for only a minority of species. The breeding rates and population changes of some migratory species have been influenced by natural changes in the availability of defoliating caterpillars. In other species, tropical deforestation is likely to have played the major role in population decline, and if recent rates of tropical deforestation continue, it is likely to affect an increasing range of migratory species in the future. Not all such species are likely to be affected adversely by deforestation, however, and some may benefit from the resulting habitat changes.

The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (Cl. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely applicable to all countries in the warm and humid region of the world.

Phytoplankton growth in many coastal and pelagic marine waters is chronically limited by nitrogen availability. Such conditions potentially favor the establishment of N2‐fixing microorganisms (eubacteria and cyanobacteria). However, planktonic and benthic N2 fixation is often either absent or present at ecologically insignificant rates. It has been proposed that deficiencies in inorganic nutrient (specifically molybdenum) availability could help explain this paradox. We examined both inorganic and organic nutrient limitations of marine N2 fixation in nitrogen‐deficient coastal North Carolina waters. Inorganic nutrient (phosphorus, iron, and molybdenum) availability consistently exceeded demands by N, fixers. In contrast, enrichment with the sugars fructose, glucose, sucrose, and maltose and the sugar alcohol mannitol either elicited N2 fixation or enhanced existing rates of N2 fixation. Supplementation with particles (organic detritus) also enhanced N2 fixation potentials; the combined addition of particles and organic compounds yielded maximum rates of N2 fixation. This combination promotes the development of O2‐reduced microenvironments (microzones) in which N2 fixers can reside. A functional explanation for the observed stimulation of N2 fixation is that it is an anaerobic process which, in aerobic marine waters, can only proceed in O2‐poor microzones. Hence, deficiencies in organic matter rather than inorganic nutrient availability may play key roles in limiting and regulating marine N2 fixation.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 496:109-124 (2014) - DOI: https://doi.org/10.3354/meps10551 Theme Section: Tracking fitness in marine vertebrates Variable thermal experience and diel thermal patterns of homing sockeye salmon in coastal marine waters S. M. Drenner1,*, S. G. Hinch1, E. G. Martins2, D. Robichaud3, T. D. Clark4, L. A. Thompson5, D. A. Patterson5, S. J. Cooke2, R. E. Thomson6,** 1Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada 2Fish Ecology and Conservation Physiology Laboratory, Institute of Environmental Science and Department of Biology, Carleton University, Ottawa, Ontario K1S 5B6, Canada3LGL Limited, 9768 Second Street, Sidney, British Columbia V8L 3Y8, Canada4Australian Institute of Marine Science, PMB 3, Townsville MC, Queensland 4810, Australia5Fisheries and Oceans Canada, Cooperative Resource Management Institute, School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada6Fisheries and Oceans Canada, Canada Institute of Ocean Science, PO Box 6000, Sidney, British Columbia V8L 4B2, Canada *Corresponding author: smdrenner@gmail.com ABSTRACT: Temperature is recognized as a key factor influencing physiology, behaviour and survival of anadromous salmonids, yet little is known about their thermal experience, nor factors affecting it, during marine homeward migrations. In 2006 and 2010, approximately 1000 Fraser River sockeye salmon Oncorhynchus nerka were captured and tagged in coastal marine waters, ~215 km from the river mouth, during their spawning migration. Individual salmon were blood sampled, gastrically implanted with temperature loggers fixed to radio or acoustic tags, and released. We recovered 50 loggers from freshwater locales containing 14690 hourly temperature readings. Mixed-effects models were used to characterize marine thermal experience, and examine the association of thermal experience with initial physiological status as well as oceanographic and meteorological conditions. Sockeye salmon thermal experience was highly variable (8.4°C to 20.5°C), and we detected opposite diel patterns between study years that could be associated with moon phase, behavioural thermoregulation, olfactory/celestial navigation or predator avoidance. We were unable to find any relationships between thermal experience and environmental conditions or fish physiological state. Nonetheless, we found that the greatest variability in thermal experience was attributed to within-individual variation, suggesting that environmental and physiological variables need to be examined at different temporal and spatial scales, and/or additional environmental and physiological variables need to be assessed. Overall, the factors associated with the thermal experience of homing sockeye salmon in coastal marine environments are more complex than previously thought, and multiple year studies are needed before generalizing behavioural patterns observed from single year studies. KEY WORDS: Temperature · Sockeye salmon · Migration · Behaviour · Physiology · Oceanography · Thermal logger · Telemetry Full text in pdf format Supplementary material **Amended author list. See Corrigendum PreviousNextCite this article as: Drenner SM, Hinch SG, Martins EG, Robichaud D and others (2014) Variable thermal experience and diel thermal patterns of homing sockeye salmon in coastal marine waters. Mar Ecol Prog Ser 496:109-124. https://doi.org/10.3354/meps10551 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 496. Online publication date: January 27, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

We discuss the problems with and the real possibilities of determining oil pollution in situ in coastal marine waters with fluorescence spectroscopy and of using artificial neural networks for data interpretation. In general, the fluorescence bands of oil and aquatic humic substance overlap. At oil concentrations in water from a few to tens of micrograms per liter, the intensity of oil fluorescence is considerably lower than that of humic substances at concentrations that typically are present in coastal waters. Therefore it is necessary to solve the problem of separating the small amount of oil fluorescence from the humic substance background in the spectrum. The problem is complicated because of possible interactions between the components and variations in the parameters of the fluorescence bands of humic substances and oil in water. Fluorescence spectra of seawater samples taken from coastal areas of the Black Sea, samples prepared in the laboratory, and numerically simulated spectra were processed with an artificial neural network. The results demonstrate the possibility of estimating oil concentrations with an accuracy of a few micrograms per liter in coastal waters also in cases in which the contribution from other organic compounds, primarily humic substances, to the fluorescence spectrum exceeds that of oil by 2 orders of magnitude and more.

‘Strongly bound’ uranium in marine waters: occurrence and analytical implications

The green turtle, Chelonia mydas, is a large, long-lived, herbivorous marine reptile that grazes on the marine macrophytes (seagrass, algae, mangrove fruit). Although green turtles are resident in shallow coastal waters for feeding, they migrate up to 2,600km to breed at traditional nesting beaches. Female green turtles do not breed annually. It takes in excess of a year for a female green turtle to lay down her fat reserves and deposit the yolk stores in her ovaries in preparation for the breeding migration. The annual number of breeding green turtles has been recorded in a monitoring program encompassing 23 years at nesting beaches within two genetically independent stocks in eastern Australia (Heron Island within the southern Great Barrier Reef breeding stock; Raine Island within the northern Great Barrier Reef breeding stock). The number of females recorded annually at the nesting beaches varies widely across years — sometimes varying up to 3 orders of magnitude in successive years. Approximately synchronous fluctuations in annual breeding numbers occur at the eastern Australian nesting beaches.An examination of the green turtles in their home feeding grounds prior to the commencement of the breeding migration shows that the inter-annual fluctuations in breeding numbers are not due to fluctuations in the number of adult turtles in the feeding areas. Rather, the annual fluctuations in breeding numbers are the result of fluctuations in the proportion of adult females that prepare to breed in a particular year.There is a significant correlation between the SOI index two years before the breeding season and the number of females recorded at the nesting beach. In the extremes, massed nesting occurs two years following major El Niño events and extremely low nesting numbers occur two years after major anti El Niño events. It is now possible to predict within reasonable confidence limits the size of the annual nesting population at key eastern Australian green turtle rookeries based on the SOI two years before the commencement of the breeding season. No comparable relationship has been identified between ENSO and any of the other species of marine turtles.Additional research suggests that there is a nutritional basis to this annual fluctuation in green turtle population parameters. Regional breadth of the phenomenon is demonstrated by the synchrony of function of green turtles that feed almost exclusively on algae on the coral reefs of the outer Great Barrier Reef with those that feed primarily on seagrass in inshore bays. However, there is no suitable database available to determine whether the fluctuations are driven by changes in quantity or quality of the food resource. Changes in water temperature alone do not appear to be sufficiently large to account for the effects.Without the linkage to ENSO regulation of breeding numbers, it has not been possible to use short term nesting census data to determine green turtle population stability. If the changes in green turtle population dynamics as a result of ENSO events are nutritionally based, then green turtle populations have the potential to provide parameters that can be monitored and compared with the performance of seagrass and algal pastures in response to environmental change. This would improve our understanding of the functioning of marine grazing ecosystems. This could apply to both changes from natural events such as climate fluctuation as well as from anthropogenic induced changes.KeywordsBreeding SeasonGreat Barrier ReefGreen TurtleMarine TurtleFeeding AreaThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Algal bioassays were used to demonstrate the high efficiency of a comnbined tertiary wastewater treatment and marine aquaculture system in removing inorganic nitrogen, and to show that the coastal waters off Woods Hole, Massachusetts, are limited in nitrogen for marine phytoplankton growth. When nutrients were removed from secondarily treated domestic wastewater through assimilation by phytoplankton in an outdoor growth pond, the pond effluent, in varying dilutions with seawater, could not support more phytoplankton growth than the seawater alone. However, when nitrogen was added back to the mixtures of pond effluent and seawater, the phytoplankton growth response was similar to that with a mixture of wastewater and seawater. This is similar to the findings of other researchers, and suggests that nitrogen may be the key growth-limiting nutrient in many coastal marine waters. The combined tertiary treatment-marine aquaculture system appears to be an effective means of removing nitrogen from secondarily treated wastewater and controlling eutrophication of coastal marine waters.

Nutrient enrichment of coastal marine waters caused by losses of nitrate (NO(3)(-)) from agriculture is an increasing global problem. In the European Union, the Nitrates Directive (ND) of 1991 was meant to be a cornerstone in reducing eutrophication effects in coastal waters downstream from intensively farmed catchments. Although reductions in losses of nitrate have been attained, very few Member States have yet been able to reduce eutrophication effects caused by inputs of NO(3)(-) from agriculture. We report trends in concentrations of NO(3)(-) and chlorophyll-a (Chl-a) in Danish coastal and open marine waters during the period from 1996 to 2011 together with an assessment of eutrophication status based on multiple indicators (e.g. nutrient concentrations, Chl-a, submerged aquatic vegetation and benthic macroinvertebrates). Despite decreasing concentrations of both NO(3)(-)and Chl-a, Danish coastal waters are not yet to be classified as 'unaffected by eutrophication'. In order to improve future pan-European evaluations of the effectiveness of the ND, we argue for the added value of including indicators and assessment principles from other European Directives, i.e. the Water Framework Directive and the Marine Strategy Framework Directive.

Territorial attendance, chick growth rate and breeding success of Arctic Skuas Stercorarius parasiticus in Shetland were lowest in the late 1980s when recruitment of Sandeels Am‐modytes marinus in the surrounding waters was poor. The relationships between both fisheries‐based and avian indices of food availability and annual variation in Arctic Skua chick growth and breeding success between 1976 and 1994 were better described by a threshold effect rather than linear functions. Arctic Skuas conform to the model proposed by Cairns, which predicts the responses of seabirds to changes in prey availability. Skua clutch size, egg volume, hatching success and hatching date were not reliable indices of Sandeel availability. However, annual fluctuations in Arctic Skua breeding numbers may be a useful indicator of changes in prey abundance.

Mate choice and nest cavity selection are directly linked to reproductive performance in seabirds, and disruption of these can result in breeding failure. The Red-billed Tropicbird Phaethon aethereus mesonauta breeds on inaccessible and remote islands, nesting primarily in natural rock cavities. I examined the relationship between reproductive performance and mate and nest cavity fidelity on St. Eustatius from 2012 to 2016, corresponding to four successive breeding seasons. The majority of nest failures occurred during the incubation stage. Pairs that failed in their first breeding attempt and laid a replacement clutch were more likely to be faithful to their mate and nest cavity within and between seasons than pairs that bred successfully. Only two replacement clutches (3.8%) were laid after the loss of a chick in the first breeding attempt, whereas the remaining 50 replacement clutches (96.2%) were laid after the loss of an egg. The stage at which pairs split had no influence on mate or nest cavity retention the following season. There were no significant differences in the weight or morphological measurements of chicks from pairs that retained their nest mate and/or cavity and those that switched. The results of this study suggest that switching nest mate or nest cavity does not necessarily improve subsequent breeding success among Red-billed Tropicbirds on St. Eustatius.

Environmental contextMarine dissolved organic matter plays a key role in the global carbon cycle. Questions remain, however, as to the influence of anthropogenic activities on its composition and distribution in coastal waters. It was found that dissolved organic matter in the vicinity of a municipal sewage effluent (Marseilles City, France) contained a high proportion of protein-like material, thereby demonstrating the influence of human activities on coastal dissolved organic matter. AbstractFluorescent dissolved organic matter (FDOM) in coastal marine waters influenced by the municipal sewage effluent (SE) from Marseilles City (France, north-western Mediterranean Sea) has been characterised. Samples were collected eleven times from September 2008 to June 2010 in the Bay of Marseilles along a coast–open sea transect from the SE outlet in the South Bay and at the Mediterranean Institute Observation site in the central Bay. Fluorescence excitation–emission matrices combined with parallel factor analysis (PARAFAC) allowed the identification of two protein-like (tyrosine C1, with excitation maxima (λEx) and an emission maximum (λEm) of <230, 275/306 nm; tryptophan C2, λEx/λEm <230, 270/346 nm) and three humic-like components (marine humic C3, λEx/λEm 280/386 nm; C4, λEx/λEm 235, 340/410 nm; C5, λEx/λEm 255, 365/474 nm). From the SE outlet to the central Bay, a gradient appeared, with decreasing FDOM intensities, decreasing dissolved organic carbon, particulate carbon, nutrients and faecal bacteria concentrations and increasing salinity values. This gradient was associated with decreasing abundances in protein-like fluorophores and rising abundances in humic-like (C3 and C5) materials. This shift in FDOM composition illustrated the decrease in wastewater inputs and the increase in marine sources of DOM along the transect. FDOM data showed that the Marseilles SE spread up to 1500 m off the outlet, but it did not reach the central Bay. Tryptophan-like material was the dominant fluorophore in the SE and displayed the highest correlations with biogeochemical parameters (organic carbon, phosphates, faecal bacteria). Therefore, it is proposed to use its fluorescence intensity to detect and track SE inputs in the Marseilles coastal marine waters.

Marine and Aquatic Communities, Stress from Eutrophication

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 148:155-168 (1997) - doi:10.3354/meps148155 Monitoring and modeling primary production in coastal waters: studies in Massachusetts Bay 1992-1994 Kelly JR, Doering PH During 1992-1994, we made shipboard incubations suitable for determining rates of primary production in water from Boston Harbor, Massachusetts Bay, and Cape Cod Bay (Massachusetts, USA). These measurements were part of an extensive baseline monitoring program to characterize water quality prior to diversion of effluent from Boston Harbor directly into Massachusetts Bay via a submarine outfall diffuser. Production (P) was measured using whole-water samples exposed to irradiance (I) levels from ~5 to 2000 µE m-2 s-1. P-I incubations were performed on 6 surveys a year, spaced to capture principal features of the annual production cycle. The number of stations and depths examined varied between years. There were 10 stations and 2 depths sampled in 1992-1993. In 1994, we performed in-depth studies at 2 stations (Boston Harbor's edge and western Massachusetts Bay) by sampling 4 depths. Using depth-intensive 1994 data a simple empirical regression model, using information on chlorophyll biomass, incident daily light, and the depth of the photic zone, predicted integrated primary production rates derived from P-I incubations. The regression model was virtually the same as described for other coastal waters, giving confidence in general use of the model as an extrapolation tool. Using the 1994-based empirical model, we obtained favorable comparisons with production rates modeled from 1992-1993 P-I incubations. Combining the regression model with data on chlorophyll, light, and the photic zone collected on frequent hydrographic surveys (up to 16 yr-1), annual primary production was estimated for 1992-1994. Primary production in an intensively studied region of western Massachusetts Bay (21 hydrographic profile stations in an area ~100 km2) ranged from 386 to 468 g C m-2 yr-1. For a station at the edge of Boston Harbor near Deer Island extrapolations suggested production rates of 263 to 546 g C m-2 yr-1. Based on 2 stations in central Cape Cod Bay (1992-1993 only), model extrapolations suggested an annual production of 527 to 613 g C m-2 yr-1. Analyses using incubation and modeling results suggested that production variability was strongly related to fluctuations in incident irradiance, especially at daily to seasonal time scales. Chlorophyll variability secondarily influenced production, especially at seasonal to annual time scales. Finally, we provide a case where equivalent production was achieved in environments with contrasting water quality (nutrient and chlorophyll concentrations) because of variations in the depth of the photic zone (controlled by both chlorophyll and non-chlorophyll turbidity). Comparative analyses showed that our study estimates of primary production were consistent with the literature on nutrient-rich shelf environments. In conclusion, our study validated an empirical modeling approach to determining primary production in coastal marine waters. Primary production · Monitoring · Modeling · Massachusetts Bay · Boston Harbor Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 148. Publication date: February 27, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research.

Estuaries are the main gateway of nutrients into marine coastal waters. Human activities and biodegradation processes in coastal freshwater and mangrove swamps are the major sources of nutrients. This study examines the sources, sinks and flux rates of nitrogen (N), phosphorus (P) and silicon (Si) through the interfaces: river estuary, mangrove estuary and ocean estuary. Measurements of the concentrations of nutrients and water velocity were made near the surface on an hourly basis, and then integrated over the flood and ebb flows over the cross-sectional area and a budget estimated over the tidal cycle, at the three interfaces. The results indicated that freshwater swamps, along the river basin, and mangrove swamps were the major source of nitrate in the estuary; the urban sewage effluent was the major source of phosphate; major sources of silicate were the freshwater swamps and coastal ocean waters. Mangrove swamp showed a tendency to retain phosphate, confirming the hypothesis that mangroves are effective sewage filters and pollutant retainers. The river exported nitrate into the estuary at a rate of 59 tons per tidal cycle, and then the estuary as a whole exported nitrate into the coastal waters at a rate of 68 tons per tidal cycle. The present study contributes to the explanation of the observed high coastal productivity of the Sofala Bank and to the development of prognostic and predictive models to quantify and predict the nutrient export to – and productivity of – coastal waters.