Thyroid hormones and halogenated organic compounds in black-legged kittiwake (Rissa tridactyla) and northern fulmar (Fulmarus glacialis)

Thyroid hormones are essential for normal growth and development and disruption of thyroid homeostasis can be critical to young developing individuals. The aim of the present study was to assess plasma concentrations of halogenated organic contaminants (HOCs) in chicks of two seabird species and to investigate possible correlations of HOCs with circulating thyroid hormone (TH) concentrations. Plasma from black-legged kittiwake (Rissa tridactyla) and northern fulmar (Fulmarus glacialis) chicks were sampled in Kongsfjorden, Svalbard in 2006. The samples were analyzed for thyroid hormones and a wide range of HOCs (polychlorinated biphenyls (PCBs), hydroxylated (OH-) and methylsulphoned (MeSO-) PCB metabolites, organochlorine pesticides (OCPs), brominated flame retardants (BFRs), and perfluorinated compounds (PFCs)). Concentrations of HOCs were generally low in kittiwake and fulmar chicks compared to previous reports. HOC concentrations were five times higher in fulmar chicks compared to in kittiwake chicks. PFCs dominated the summed HOCs concentrations in both species (77% in kittiwakes and 69% in fulmars). Positive associations between total thyroxin (TT4) and PFCs (PFHpS, PFOS, PFNA) were found in both species. Although correlations do not implicate causal relationships per se, the correlations are of concern as disruption of TH homeostasis may cause developmental effects in young birds.

A comparison of seabird abundance in three inlets in Nootka Sound, British Columbia: Muchalat, Zeballos, & Tahsis

Senior thesis written for Oceanography 445

Estimating Baselines and Identifying Anomalies in Beached Bird Patterns on the Outer Coasts of Washington and Oregon, USA

Thesis (Master's)--University of Washington, 2016-06

Nitrogen ecophysiology of Heron Island, a subtropical coral cay of the Great Barrier Reef, Australia

Coral cays form part of the Australian Great Barrier Reef. Coral cays with high densities of seabirds are areas of extreme nitrogen (N) enrichment with deposition rates of up to 1000 kg N ha(-1) y(-1). The ways in which N sources are utilised by coral cay plants, N is distributed within the cay, and whether or not seabird-derived N moves from cay to surrounding marine environments were investigated. We used N metabolite analysis, N-15 labelling and N-15 natural abundance (delta(15)N) techniques. Deposited guano-derived uric acid is hydrolysed to ammonium (NH4+) and gaseous ammonia (NH3). Ammonium undergoes nitrification, and nitrate (NO3-) and NH4+ were the main forms of soluble N in the soil. Plants from seabird rookeries have a high capacity to take up and assimilate NH4+, are able to metabolise uric acid, but have low rates of NO3- uptake and assimilation. We concluded that NH4+ is the principal source of N for plants growing at seabird rookeries, and that the presence of NH4+ in soil and gaseous NH3 in the atmosphere inhibits assimilation of NO3-, although NO3- is taken up and stored. Seabird guano, Pisonia forest soil and vegetation were similarly enriched in N-15 suggesting that the isotopic enrichment of guano (delta(15)N 9.9parts per thousand) carries through the forest ecosystem. Soil and plants from woodland and beach environments had lower delta(15)N (average 6.5parts per thousand) indicating a lower contribution of bird-derived N to the N nutrition of plants at these sites. The aquifer under the cay receives seabird-derived N leached from the cay and has high concentrations of N-15-enriched NO3- (delta(15)N 7.9parts per thousand). Macroalgae from reefs with and without seabirds had similar delta(15)N values of 2.0-3.9parts per thousand suggesting that reef macroalgae do not utilise N-15-enriched seabird-derived N as a main source of N. At a site beyond the Heron Reef Crest, macroalgae had elevated delta(15)N of 5.2parts per thousand, possibly indicating that there are locations where macroalgae access isotopically enriched aquifer-derived N. Nitrogen relations of Heron Island vegetation are compared with other reef islands and a conceptual model is presented.

Microspectrophotometry of visual pigments and oil droplets in a marine bird, the wedge-tailed shearwater Puffinus pacificus: Topographic variations in photoreceptor spectral characteristics

Microspectrophotometric examination of the retina of a procellariiform marine bird, the wedge-tailed shearwater Puffinus pacificus, revealed the presence of five different types of vitamin A(1)-based visual pigment in seven different types of photoreceptor. A single class of rod contained a medium-wavelength sensitive visual pigment with a wavelength of maximum absorbance (lambda(max)) at 502 nm. Four different types of single cone contained visual pigments maximally sensitive in either the violet (VS, lambda(max) 406 nm), short (SWS, lambda(max) 450 nm), medium (MWS, lambda(max) 503 nm) or long (LWS, lambda(max) 566 nm) spectral ranges. In the peripheral retina, the SWS, MWS and LWS single cones contained pigmented oil droplets in their inner segments with cut-off wavelengths (lambda(cut)) at 445 (C-type), 506 (Y-type) and 562 nm (R-type), respectively. The VS visual pigment was paired with a transparent (T-type) oil droplet that displayed no significant absorption above at least 370 run. Both the principal and accessory members of the double cone pair contained the same 566 nm lambda(max) visual pigment as the LWS single cones but only the principal member contained an oil droplet, which had a lambda(cut) at 413 nm. The retina had a horizontal band or 'visual streak' of increased photoreceptor density running across the retina approximately 1.5 mm dorsal to the top of the pecten. Cones in the centre of the horizontal streak were smaller and had oil droplets that were either transparent/colourless or much less pigmented than at the periphery. It is proposed that the reduction in cone oil droplet pigmentation in retinal areas associated with high visual acuity is an adaptation to compensate for the reduced photon capture ability of the narrower photoreceptors found there. Measurements of the spectral transmittance of the ocular media reveal that wavelengths down to at least 300 nm would be transmitted to the retina.

The importance of marine subsidies for terrestrial consumers in coastal Peru

The Peruvian coast is one the best examples of cross-ecosystem food web exchanges, in which resources from one of the richest marine ecosystems subsidize consumers in one of the driest deserts on Earth. Marine subsidies are resources that originate in the marine ecosystem, and that contribute to increase the density of consumers in the recipient ecosystem. I examined the effects of marine subsidies on animal populations in the Peruvian coastal desert. ^ I combined several approaches to study the linkages between marine resources and terrestrial consumers, such as surveying the spatial distribution and estimating the relative abundance of terrestrial consumers, studying the diet of geckos and lizards through stomach content analyses, and examining the desert food web with carbon and nitrogen stable isotope analyses. ^ I found that the distribution and diet of desert consumers were tightly coupled to the availability of marine subsidies. I revealed linkages along two pathways of nutrient fluxes: tidal action that washes ashore macroalgae and cadavers of marine organisms, and animal transport in places where pinnipeds and seabirds congregate for reproduction. In the first pathway, intertidal algivivores made marine resources available to terrestrial consumers by moving between the intertidal and supratidal zone. The relative contribution of terrestrial and algal carbon sources varied among terrestrial consumers, because scorpions assimilated a lower proportion of energy from macroalgae than did geckos and solifuges. In the second pathway, I found that pinniped colonies influenced the diet of desert consumers, and contributed to support large populations of lizards and geckos. By combining field observations, and stomach and stable isotope analyses, I constructed a simplified food web for a large sea lion colony, showing the number of trophic levels that originate from pinniped-derived nutrients. ^ My study demonstrates the enormous importance of marine resources for the diet of desert consumers. The near absence of rainfall along the Peruvian coast promotes an extreme dependence of terrestrial consumers on marine resources, and causes permanent food web effects that are affected by temporal variability in marine productivity, rather then temporal patterns of desert plant growth. ^

Ecosystem Structure and Function Still Altered Two Decades After Short-Term Fertilization of a Seagrass Meadow

An oligotrophic phosphorus (P) limited seagrass ecosystem in Florida Bay was experimentally fertilized in a unique way. Perches were installed to encourage seabirds to roost and deliver an external source of nutrients via defecation. Two treatments were examined: (1) a chronic 23-year fertilization and (2) an earlier 28-month fertilization that was discontinued when the chronic treatment was initiated. Because of the low mobility of P in carbonate sediments, we hypothesized long-term changes to ecosystem structure and function in both treatments. Structural changes in the chronic treatment included a shift in the dominant seagrass species from Thalassia testudinum to Halodule wrightii, large increases in epiphytic biomass and sediment chlorophyll-a, and a decline in species richness. Functional changes included increased benthic metabolism and quantum efficiency. Initial changes in the 28-month fertilization were similar, but after 23 years of nutrient depuration T. testudinum has reestablished itself as the dominant species. However, P remains elevated in the sediment and H. wrightii has maintained a presence. Functionally the discontinued treatment remains altered. Biomass exceeds that in the chronic treatment and indices of productivity, elevated relative to control, are not different from the chronic fertilization. Cessation of nutrient loading has resulted in a superficial return to the pre-disturbance character of the community, but due to the nature of P cycles functional changes persist.

Breeding success and traits of equal and unequal pairs of little penguins (Eudyptula minor) on Phillip Island during 2001-2008

According to life-history theory, individuals optimize their decisions in order to maximize their fitness. This raises a conflict between parents, which need to cooperate to ensure the propagation of their genes but at the same time need to minimize the associated costs. Trading-off between benefits and costs of a reproduction is one of the major forces driving demographic trends and has shaped several different parental care strategies. Using little penguins (Eudyptula minor) as a model, we investigated whether individuals of a pair provide equal parental effort when raising offspring and whether their behavior was consistent over 8 years of contrasting resource availability. Using an automated identification system, we found that 72% of little penguin pairs exhibited unforced (i.e., that did not result from desertion of 1 parent) unequal partnership through the postguard stage. This proportion was lower in favorable years. Although being an equal pair appeared to be a better strategy, it was nonetheless the least often observed. Individuals that contributed less than their partner were not less experienced (measured by age), and gender did not explain differences between partners. Furthermore, birds that contributed little or that contributed a lot tended to be consistent in their level of contribution across years. We suggest that unequal effort during breeding may reflect differences in individual quality, and we encourage future studies on parental care to consider this consistent low and high contributor behavior when investigating differences in pair investment into its offspring. Key words: attendance patterns, individual quality, meal size, parental care, reproductive costs, seabirds.

The Southern Ocean and South Pacific Region

The Region comprises three sub-regions (FAO Statistical Areas) with very different characteristics. The South Pacific includes the vast and virtually unpopulated Southern Ocean surrounding the Antarctic. It has the world’s largest fisheries off Peru and Chile and some of the world’s best managed fisheries in Australia and New Zealand. The Region has over 27% of the world’s ocean area and over 98% of the Region’s total area of 91 million km2 is ‘open ocean’. The Region contains less than 5% of the global continental shelf area and only a fraction of this area is covered by three large marine ecosystems (the New Zealand Shelf, the Humboldt Current and the Antarctic large marine ecosystems (LMEs). The Humboldt Current System (HCS) is the world’s largest upwelling which provides nutrients for the world’s largest fisheries. The Region also has a high number of seamounts. The marine capture fisheries of the Region produce over 13 million tons annually and an expanding aquaculture industry produces over 1.5 million tons. Peru’s anchoveta fishery provides about half the world’s supply of fish meal and oil, key ingredients of animal and fish feeds. El Niño Southern Oscillations (ENSOs), known more generally as El Niños, can substantially change the species composition of the key small pelagic catches (anchovy, sardine, horse mackerel and jack mackerel) causing production to fluctuate from about 4-8 million tons. Partly due to the lack of upwelling and shelf areas, fisheries production in the Southern Ocean and Area 81 is relatively small but supports economically important commercial and recreational fisheries and aquaculture in New Zealand and in New South Wales (Australia). Krill remains a major underexploited resource, but is also a keystone species in the Antarctic food web. The Region is home to numerous endangered species of whales, seals and seabirds and has a high number of seamounts, vulnerable ecosystems fished for high-value species such as orange roughy.

The Southern Ocean and South Pacific Region

The Region comprises three sub-regions (FAO Statistical Areas) with very different characteristics. The South Pacific includes the vast and virtually unpopulated Southern Ocean surrounding the Antarctic. It has the world’s largest fisheries off Peru and Chile and some of the world’s best managed fisheries in Australia and New Zealand. The Region has over 27% of the world’s ocean area and over 98% of the Region’s total area of 91 million km2 is ‘open ocean’. The Region contains less than 5% of the global continental shelf area and only a fraction of this area is covered by three large marine ecosystems (the New Zealand Shelf, the Humboldt Current and the Antarctic large marine ecosystems (LMEs). The Humboldt Current System (HCS) is the world’s largest upwelling which provides nutrients for the world’s largest fisheries. The Region also has a high number of seamounts. The marine capture fisheries of the Region produce over 13 million tons annually and an expanding aquaculture industry produces over 1.5 million tons. Peru’s anchoveta fishery provides about half the world’s supply of fish meal and oil, key ingredients of animal and fish feeds. El Niño Southern Oscillations (ENSOs), known more generally as El Niños, can substantially change the species composition of the key small pelagic catches (anchovy, sardine, horse mackerel and jack mackerel) causing production to fluctuate from about 4-8 million tons. Partly due to the lack of upwelling and shelf areas, fisheries production in the Southern Ocean and Area 81 is relatively small but supports economically important commercial and recreational fisheries and aquaculture in New Zealand and in New South Wales (Australia). Krill remains a major underexploited resource, but is also a keystone species in the Antarctic food web. The Region is home to numerous endangered species of whales, seals and seabirds and has a high number of seamounts, vulnerable ecosystems fished for high-value species such as orange roughy.

Navigating uncertain waters: a critical review of inferring foraging behaviour from location and dive data in pinnipeds

In the last thirty years, the emergence and progression of biologging technology has led to great advances in marine predator ecology. Large databases of location and dive observations from biologging devices have been compiled for an increasing number of diving predator species (such as pinnipeds, sea turtles, seabirds and cetaceans), enabling complex questions about animal activity budgets and habitat use to be addressed. Central to answering these questions is our ability to correctly identify and quantify the frequency of essential behaviours, such as foraging. Despite technological advances that have increased the quality and resolution of location and dive data, accurately interpreting behaviour from such data remains a challenge, and analytical methods are only beginning to unlock the full potential of existing datasets. This review evaluates both traditional and emerging methods and presents a starting platform of options for future studies of marine predator foraging ecology, particularly from location and two-dimensional (time-depth) dive data. We outline the different devices and data types available, discuss the limitations and advantages of commonly-used analytical techniques, and highlight key areas for future research. We focus our review on pinnipeds - one of the most studied taxa of marine predators - but offer insights that will be applicable to other air-breathing marine predator tracking studies. We highlight that traditionally-used methods for inferring foraging from location and dive data, such as first-passage time and dive shape analysis, have important caveats and limitations depending on the nature of the data and the research question. We suggest that more holistic statistical techniques, such as state-space models, which can synthesise multiple track, dive and environmental metrics whilst simultaneously accounting for measurement error, offer more robust alternatives. Finally, we identify a need for more research to elucidate the role of physical oceanography, device effects, study animal selection, and developmental stages in predator behaviour and data interpretation.

When males are more inclined to stay at home :Insights into the partial migration of a pelagic seabird provided by geolocators and isotopes

Partial migration has never been studied in pelagic seabirds, but investigating old unresolved questions in new contexts can provide useful fresh insights. We used geolocators and stable isotopes to investigate this phenomenon in a migratory pelagic seabird, the Cory’s shearwater (Calonectris diomedea). Although most birds migrated to the southern hemisphere, 8.1% of studied birds (N = 172) remained close to the breeding colony (Selvagem Grande, Madeira, Portugal), foraging within the Canary current. Almost all resident birds were males, while age or body size did not predict migratory status. Despite displaying a high repeatability (R = 0.72) in the choice of wintering area, residency was not a fixed strategy and individuals could switch between migrating and staying in the Canary current in different years. The predictions resulting from the “body size” and the “social dominance” hypotheses, in which larger individuals or dominant individuals, respectively, remain closer to the breeding areas, were not supported by our data. Resident males were able to occupy the nesting burrows much earlier than migratory males and arrival time in this species is known to affect the probability of engaging in a reproductive attempt. The selective pressure to arrive early at the colony is therefore the most likely explanation for the maintenance of this partial migration system.

Distribution and at-sea activity of a nocturnal seabird, the Bulwer's petrel Bulweria bulwerii, during the incubation period

Bulwer'spetrelsarenocturnalseabirdsthatmostlypreyonmesopelagicfauna.Asaerialforagersand shallowdivers,theirfeedingopportunitiesarelimitedbynear-surfaceavailabilityoftheirprey,whichis highlyvariablebothtemporally(reflectingdiurnalandlunarcycles)andspatially.Herewestudiedhow Bulwer'spetrelscopewiththeseconstraintsbyanalysingtheirat-seadistributionandactivityduringthe incubationperiod.Wetrackedthemovementsof20birdsfromSelvagemGrande(NEAtlantic)duringa completelunarcycle,andrecorded30foragingtripsthatlasted11daysonaverage.Birdswereboth distributedaroundthecolonyandinwatersclosetotheAzoreanarchipelago(mid-Atlantic)located 1700kmaway,andweresignificantlymoreactiveatnight(especiallyjustaftersunsetandbeforesunrise), whenmesopelagicfaunaisalsoclosertotheseasurfaceduetotheirdielverticalmigrations.Bulwer's petrelsspentsignificantlymoretime flyingduringmoonlight,althoughtheeffectofthemoonwasrela- tivelyweak(ca.10–15%differencebetweenmoonlitanddarkperiodsofthenight),andnotobviouswhen birdswereforaginginmid-Atlanticwaters,whichwerealsotargetedmoreoftenduringfull-moon.These resultsrevealkeyadaptationsoftheBulwer'spetreltothehighlydynamicecologyofitsmesopelagicprey.

Migration, prospecting, dispersal? What host movement matters for infectious agent circulation?

Spatial disease ecology is emerging as a new field that requires the integration of complementary approaches to address how the distribution and movements of hosts and parasites may condition the dynamics of their interactions. In this context, migration, the seasonal movement of animals to different zones of their distribution, is assumed to play a key role in the broad scale circulation of parasites and pathogens. Nevertheless, migration is not the only type of host movement that can influence the spatial ecology, evolution, and epidemiology of infectious diseases. Dispersal, the movement of individuals between the location where they were born or bred to a location where they breed, has attracted attention as another important type of movement for the spatial dynamics of infectious diseases. Host dispersal has notably been identified as a key factor for the evolution of host-parasite interactions as it implies gene flow among local host populations and thus can alter patterns of coevolution with infectious agents across spatial scales. However, not all movements between host populations lead to dispersal per se. One type of host movement that has been neglected, but that may also play a role in parasite spread is prospecting, i.e., movements targeted at selecting and securing new habitat for future breeding. Prospecting movements, which have been studied in detail in certain social species, could result in the dispersal of infectious agents among different host populations without necessarily involving host dispersal. In this article, we outline how these various types of host movements might influence the circulation of infectious disease agents and discuss methodological approaches that could be used to assess their importance. We specifically focus on examples from work on colonial seabirds, ticks, and tick-borne infectious agents. These are convenient biological models because they are strongly spatially structured and involve relatively simple communities of interacting species. Overall, this review emphasizes that explicit consideration of the behavioral and population ecology of hosts and parasites is required to disentangle the relative roles of different types of movement for the spread of infectious diseases.