Studies on terns with particular reference to feeding ecology

Four species of sea terns in the genus Sterna were studied primarily to determine how they differed in strategies used to exploit available food, and to identify factors that influenced their success in obtaining it. Where the four species coexisted during the breeding season, interspecific differences were found in feeding dispersion, dive height, immersion time, use of 'contact-dipping' and size of prey taken. These variations should alleviate competition for food, and therefore facilitate coexistence. The food-robbing behaviour exhibited by Roseate Terns on Coquet Island was examined. The intensity and success of attacks were correlated with the density of "host" terns. Fish size affected the likelihood of attack, and of robbing success. Several variables were found to influence rates of fish capture at sea. Feeding rates contained both diurnal and tidal patterns, the latter corresponding with tidal variations in the rate of fish capture in the littoral zone. In Africa, first-winter Sandwich Terns were less successful than older birds at catching fish, suggesting that foraging skill is acquired gradually. An assessment of weather factors influencing fishing success, and growth rates of chicks indicated that windspeed and/or sea surface disturbance increase to levels that optimise fishing ability of inshore-feeding terns, after which their effects become detrimental. The inimical effects of paralytic shellfish poisoning on the breeding success of terns in 1968 are described. Analysis of the composition of tern eggs demonstrated significant differences between the terminal egg and the prior egg(s) of any laying sequence. The adaptedness of terns to a variable food supply is discussed with reference to other predator-prey systems. Hypotheses for the causation and function of deferred maturity in birds and other animals are assessed in relation to the slow acquisition of foraging skills by Sandwich Terns and some other seabirds

Ecological roles and importance of sharks in the Anthropocene Ocean

In ecosystems, sharks can be predators, competitors, facilitators, nutrient transporters, and food. However, overfishing and other threats have greatly reduced shark populations, altering their roles and effects on ecosystems. We review these changes and implications for ecosystem function and management. Macropredatory sharks are often disproportionately affected by humans but can influence prey and coastal ecosystems, including facilitating carbon sequestration. Like terrestrial predators, sharks may be crucial to ecosystem functioning under climate change. However, large ecosystem effects of sharks are not ubiquitous. Increasing human uses of oceans are changing shark roles, necessitating management consideration. Rebuilding key populations and incorporating shark ecological roles, including less obvious ones, into management efforts are critical for retaining sharks’ functional value. Coupled social-ecological frameworks can facilitate these efforts

Kittiwake breeding success in the southern North Sea correlates with prior sandeel fishing mortality

In the North Sea, sandeels provide a vital food source for breeding seabirds, but are also the target of an industrial fishery. GPS tracking suggests that the most productive fishing grounds overlap with foraging areas of black-legged kittiwakes from eastern England, raising the prospect that the fishery could affect the birds. Rising sea temperatures also threaten sandeels, so kittiwake food supplies could be affected by local and larger-scale processes. Drivers of kittiwake breeding success at Flamborough Head and Bempton Cliffs Special Protection Area, the UK's largest colony, and one of the closest to the sandeel fishing grounds, were examined. Relationships between sandeel stocks, sea surface temperature and kittiwake breeding success were analysed with generalized linear mixed models and generalized linear models, with model performance assessed using the Akaike Information Criterion and R2. Higher kittiwake breeding success was associated with higher sandeel spawning stock biomass (SSB; biomass of sexually mature fish) the preceding winter (R2 = 21.5%) and lower sandeel fishing mortality two years previously (R2 = 22.3%). After temporal trends were removed, only the fishing mortality effect remained. Models with multiple predictors supported the importance of fishing mortality. Higher sandeel SSB was associated with lower temperatures (R2 = 15.2–38.6%) and lower sandeel fishing mortality (R2 = 24.2–26.1%). Hence, lower temperatures and fishing mortality were positively associated with sandeel biomass, and higher sandeel biomass and lower fishing mortality were positively associated with kittiwake productivity. In light of worsening environmental conditions and declining sandeel and kittiwake populations, careful consideration should be given to the requirements of sandeel-dependent predators when making fishery management decisions

The relationship between tumor inflammatory cell infiltrate and outcome in patients with pancreatic ductal adenocarcinoma

<p>Background: The tumor-associated inflammatory cell infiltrate is recognized to have prognostic value in various common solid tumors. However, the prognostic value of the tumor inflammatory cell infiltrate has not been established in pancreatic ductal adenocarcinoma (PDAC) nor has its relationship with the systemic inflammatory response.</p> <p>Methods: Retrospective study was made of 173 patients who underwent surgery between 1997 and 2009. Routine pathology specimens were scored according to density of the tumor inflammatory cell infiltrate, and biochemical data were collected preoperatively.</p> <p>Results: Low-grade tumor inflammatory cell infiltrate was associated with earlier tumor recurrence (P < 0.001) and particularly in the liver (P = 0.027). It was also associated with T3 tumors (P < 0.05), lymph node involvement (P < 0.05), and resection margin involvement (P < 0.05). On univariate survival analysis, age <65 years (P < 0.05), mGPS (P < 0.001), increased tumor stage (P < 0.01), nodal involvement (P < 0.01), size (P < 0.05), grade (P < 0.05), perineural invasion (P < 0.05), venous invasion (P < 0.01), resection margin involvement (P ≤ 0.001), vascular reconstruction (P < 0.05), and no adjuvant chemotherapy (P < 0.05) were associated with poor survival. In contrast, high-grade tumor inflammatory cell infiltrate was associated with better survival (P < 0.001). On multivariate survival analysis, mGPS [hazard ratio (HR): 1.77, 95 % confidence interval (95 % CI): 1.19–2.62, P = 0.005], tumor stage (HR: 2.21, 95 % CI: 1.16–4.23, P = 0.016), resection margin involvement (HR: 2.19, 95 % CI: 1.41–3.44, P = 0.001), venous invasion (HR: 1.79, 95 % CI: 1.22–2.63, P = 0.003), tumor inflammatory cell infiltrate (HR: 0.37, 95 % CI: 0.25–0.55, P = 0.0001), and adjuvant chemotherapy (P = 0.04) were independently prognostic.</p> <p>Conclusions: The results of the study show, for the first time, that the presence of a high-grade tumor inflammatory cell infiltrate is an independent predictor of prolonged overall survival following resection for PDAC. Furthermore, measures of the local and the systemic inflammatory response were inversely associated.</p&gt

Ecological roles and importance of sharks in the Anthropocene Ocean

In ecosystems, sharks can be predators, competitors, facilitators, nutrient transporters, and food. However, overfishing and other threats have greatly reduced shark populations, altering their roles and effects on ecosystems. We review these changes and implications for ecosystem function and management. Macropredatory sharks are often disproportionately affected by humans but can influence prey and coastal ecosystems, including facilitating carbon sequestration. Like terrestrial predators, sharks may be crucial to ecosystem functioning under climate change. However, large ecosystem effects of sharks are not ubiquitous. Increasing human uses of oceans are changing shark roles, necessitating management consideration. Rebuilding key populations and incorporating shark ecological roles, including less obvious ones, into management efforts are critical for retaining sharks' functional value. Coupled social-ecological frameworks can facilitate these efforts.</p