Using scales to clarify the transition from blue-phase to brown-phase fingerling in Notothenia rossii from the South Shetland Islands

Scales and whole otoliths were read for age determination in early stages of Notothenia rossii caught in Potter Cove, South Shetland Islands, in summer seasons 2003–2006 and 2008. The sample comprised blue-phase pelagic fingerlings of 7.0–7.6 cm (TL) of age group 0 year and demersal brown-phase fingerlings/juveniles of 8.5–20.9 cm and predominant age groups 1–2 years. Counting of sclerites facilitated the interpretation of the rings, particularly in the central scale. To clarify two previous issues of controversy, we deduce that the duration of the offshore pelagic blue-phase fingerling stage is less than one year before migration to the nearshore demersal habitat. Furthermore, the first well-defined ring in scales corresponded to the first annulus, while a contiguous ring was a secondary ring sometimes deposited after the first winter during the second year of life, attributable to a shift of habitat from pelagic to demersal. A von Bertalanffy growth curve was computed by combining age/length data of the juvenile phase of N. rossii from this and a previous study at Potter Cove with literature data from the offshore adult population, resulting in the following equation: L_t = 8 6. 9  ( 1- \texte ^{- 0. 0 9 1 (t - 0. 6 6 8 )} ) L_{t} = 8 6. 9 \,\left( { 1- {\text{e}}^{{ - 0. 0 9 1 (t - 0. 6 6 8 )}} } \right) _.     

Seasonal variations in larval biomass and biochemical composition of brown shrimp, Crangon crangon (Decapoda, Caridea), at hatching

The “brown shrimp”, Crangon crangon (Linnaeus 1758), is a benthic key species in the North Sea ecosystem, supporting an intense commercial fishery. Its reproductive pattern is characterized by a continuous spawning season from mid-winter to early autumn. During this extended period, C. crangon shows significant seasonal variations in egg size and embryonic biomass, which may influence larval quality at hatching. In the present study, we quantified seasonal changes in dry weight (W) and chemical composition (CHN, protein and lipid) of newly hatched larvae of C. crangon. Our data revealed significant variations, with maximum biomass values at the beginning of the hatching season (February–March), a decrease throughout spring (April–May) and a minimum in summer (June–September). While all absolute values of biomass and biochemical constituents per larva showed highly significant differences between months (P < 0.001), CHN, protein and lipid concentrations (expressed as percentage values of dry weight) showed only marginally significant differences (P < 0.05). According to generalized additive models (GAM), key variables of embryonic development exerted significant effects on larval condition at hatching: The larval carbon content (C) was positively correlated with embryonic carbon content shortly after egg-laying (r ² = 0.60; P < 0.001) and negatively with the average incubation temperature during the period of embryonic development (r ² = 0.35; P < 0.001). Additionally, water temperature (r ² = 0.57; P < 0.001) and food availability (phytoplankton C; r ² = 0.39; P < 0.001) at the time of hatching were negatively correlated with larval C content at hatching. In conclusion, “winter larvae” hatching from larger “winter eggs” showed higher initial values of biomass compared to “summer larvae” originating from smaller “summer eggs”. This indicates carry-over effects persisting from the embryonic to the larval phase. Since “winter larvae” are more likely exposed to poor nutritional conditions, intraspecific variability in larval biomass at hatching is interpreted as part of an adaptive reproductive strategy compensating for strong seasonality in plankton production and transitory periods of larval food limitation.     

Beaching of the tunicate<Emphasis Type="Italic"> Salpa thompsoni</Emphasis> at high levels of suspended particulate matter in the Southern Ocean

A mass death event of the pelagic tunicate Salpa thompsoni, which occurred in April 2002 in Potter Cove near the Argentinean/German Antarctic station Jubany (62°14′S–58°40′W), King George Island, South Shetland Islands, is described. Salps appeared on the beach 2 days after very strong (>80 km.h⁻¹) winds were registered, which accumulated particulate material in the inner part of the cove and probably also re-suspended bottom sediments. The sharp increase in particulate-matter concentrations in Potter Cove caused clogging of salp mucous filtering nets, and probably a combination of clogging, winds and tides caused dying salps to be washed out onto the beach.     

Age validation of juvenile Notothenia rossii at Potter Cove, South Shetland Islands, using mark-recapture data

Among all validation methods of age determination in fish, release of known age and marked specimens gives the most reliable information. We carried out a tag-recapture experiment on Notothenia rossii at Potter Cove, to validate, for first time for this species using this method, the principle of annual deposition of an annulus in scales and otoliths. Of 132 juvenile specimens (TL = 22.1–38.1 cm) tagged and released in successive years from 2004 to 2010, 7 were recaptured at the same site after periods of 1–13 months. In scales of five specimens recovered after 10–13 months, one extra annulus was laid down, exhibiting an additional winter zone of closely spaced sclerites. Consistently, the same analysis in two individuals marked and recaptured during the same summer, after 1–3 months at liberty, did not show the deposition of an additional annulus. All the fish tagged or recaptured during the experiment period (December to March) showed in their scales an edge zone of widely spaced sclerites, in agreement with the known pattern of growth in summer. Likewise, an analysis in selected specimens showed good consistency between the numbers of sclerites deposited in scales and the time of fish release. The comparative analysis between scales taken at recapture and otoliths of the same individual allowed a simultaneous counting of the annuli with complete correspondence. The growth in length of fish ranged from 0.5 to 6.1 cm, depending on the time of release.     

Early ontogeny of the mackerel icefish, Champsocephalus gunnari, in the southern Scotia Arc

During the early ontogeny of fishes, the timing and duration of key events such as larval hatching and the switch from endogenous to exogenous feeding largely determine the offspring viability and survival. The aim of the present study was to investigate the life history traits of the early larvae of the mackerel icefish, Champsocephalus gunnari, collected in summer south of the South Shetland Islands in the Bransfield Strait and north of Elephant Island. Through the analysis of sagittal otolith microstructure, we assessed the timing and duration of egg incubation, larval hatching, first exogenous feeding, rate of yolk resorption and body growth rate. Compared to populations living further north (i.e. around South Georgia and Kerguelen Islands), mackerel icefish in the southern Scotia Arc exhibits longer egg incubation (lasting 90–120 days from winter to summer) and delayed hatching time spread over a relatively short period lasting 26 days between January and February. The first exogenous feeding takes place between 13 and 24 days after hatching still in the presence of the yolk-sac, indicating a prolonged mixed feeding afterward. The specific growth rate or daily percentage change in size (G) was 1.9 % SL day^?1, corresponding to a daily growth rate at mean size of 0.31 mm day^?1. While showing significant differences in early life history traits across their geographical distribution, C. gunnari populations share a common strategy, spawning a small number of large eggs that hatch in relatively large-sized larvae, at a time which may be independent of the timing of pack-ice retreat and onset of the production cycle.     

Summer macroalgal biomass in Potter Cove,South Shetland Islands,Antarctica: its production and flux to the ecosystem

Summer macroalgal biomass and production were analyzed at Potter Cove, King George Island, Antarctica and the potential carbon transfer of macroalgal production to the coastal ecosystem of the cove was estimated. A total of 38 algal species were found, with Desmarestia anceps, D. menziesii and Himantothallus grandifolius accounting for almost 80% of the biomass. Biomass data and published growth rates were combined to calculate the production of the five most abundant species. The standing stock for each summer month was estimated as the product of the average biomass and the area of the macroalgal stands. The monthly biomass production was calculated for each species by difference between the expected biomass and the observed biomass at the previous month. The macroalgal production showed a decreasing trend during the summer months. The average standing stock in the whole cove was 792.84 MT and the production was 1,401.33 MT during the summer 1994–1995. The flux of biomass to the ecosystem during the summer period was 1,370.61 MT, which is almost as much as the total summer production. The study demonstrates that macroalgae are one of the main energy sources in Potter Cove, and probably support a large fraction of the secondary production of the benthos.     

Feeding ecology of benthic filter-feeders at Potter Cove,an Antarctic coastal ecosystem

A rich benthic filter-feeding community is present at Potter Cove, South Shetland, in spite of some usually unfavorable conditions affecting their feeding ecology, such as low phytoplankton production in summer and high sedimentation rates. However, organic material that could fuel the benthic system, such as macroalgal fragments, was detected in the water-bottom interface year-round. Mean assimilation efficiency of several sizes of macroalgal particles under different inorganic particulate percentages varied between 26–51% in a clam, and 26–72% in two ascidian species. Estimated particle flux (feces) produced by ascidians varied according to species and abundance. The C:N ratio of feces was relatively high. Plasticity and profit from the available food sources contribute to the success of the filter-feeding community in Potter Cove.     

Analysis of dietary overlap in Antarctic fish (Notothenioidei) from the South Shetland Islands: no evidence of food competition

A dietary overlap analysis between notothenioid species was carried out among three fish assemblages in the South Shetland Island area. Using Tyler's (1972) method, the re-occurrence of main and secondary prey among fish predators was 33% in summer and 37% over the year at Potter Cove, 25% in summer and 7% in winter at Admiralty Bay, and 20% in autumn/winter around Elephant Island. Likewise, using the "S" index of Linton et al. (1981), the diet similarity between most species pairs is <50%. This relatively low dietary overlap may be explained by the about equally divided occurrence of generalised feeders and specialised feeders, with no evidence of competition among them. The fishes' trophic niches seem to be separated by depth and prey taxa. These findings are compared with other Antarctic fish communities and those in similar non-Antarctic cold marine ecosystems.     

Population dynamics, growth and reproduction of Corophium insidiosum (Crustacea: Amphipoda) at low salinities in Monolimni lagoon (Evros Delta, North Aegean Sea)

Distribution, population dynamics, growth and aspects of reproductive biology of Corophium insidiosum were investigated in Monolimni lagoon. Samples were collected in July 1997 (at 30 psu S) and during February 1998–May 1999 (at 0.1–5.7 psu S). Corophium insidiosumwas almost exclusively found in the outer part of the lagoon, which showed a higher water renewal rate. Population density gradually decreased during winter and spring, when salinity was lower than 1 psu and the amphipod finally vanished from the lagoon. Salinity increase during summer (1.2–5.7 psu) was followed by the re-occurrence of C. insidiosum with a time lag of 2–3 months. Population density increased in autumn and peaked in early winter at salinities 1.6–4.2 psu. Three cohorts appeared in the population during September 1998–March 1999. Breeding activity peaked in early autumn (14–21?°C, 4 psu S) and ceased after December (2–6.5?°C, ¡1.5 psu S). The preponderance of females in the large size classes resulted in a female- biased sex ratio in the whole population. The population showed a growth rate of 7.5–11.2 μm d^?1 being faster in autumn (9–21?°C, 3–4 psu S) than in winter (2–12?°C, 0.2–3 psu). An exponential relation existed between body length and cephalic length or dry body weight, while brood size was directly related to body length. Mean brood size was small (4.96 early embryos) and egg loss during development high (53%), possibly as a consequence of low salinities.     

An assessment of karstic submarine groundwater and associated nutrient discharge to a Mediterranean coastal area (Balearic Islands, Spain) using radium isotopes

Short and long-lived radium isotopes (²²³Ra, ²²⁴Ra, ²²⁶Ra, ²²⁸Ra) were used to quantify submarine groundwater discharge (SGD) and its associated input of inorganic nitrogen (NO₃ ^?), phosphorus (PO₄ ^3?) and silica (SiO₄ ^4?) into the karstic Alcalfar Cove, a coastal region of Minorca Island (Western Mediterranean Sea). Cove water, seawater and groundwater (wells and karstic springs) samples were collected in May 2005 and February 2006 for radium isotopes and in November 2007 for dissolved inorganic nutrients. Salinity profiles in cove waters suggested that SGD is derived from shallow brackish springs that formed a buoyant surface fresh layer of only 0.3 m depth. A binary mixing model that considers the distribution of radium activities was used to determine the cove water composition. Results showed that cove waters contained 20% brackish groundwater; of which 6% was recirculated seawater and 14% corresponded to freshwater discharge. Using a radium-derived residence time of 2.4 days, a total SGD flux of 150,000 m³ year^?1 was calculated, consisting of 45,000 m³ year^?1 recirculated seawater and 105,000 m³ year^?1 fresh groundwater. Fresh SGD fluxes of NO₃ ^?, SiO₄ ^4? and PO₄ ^3? were estimated to be on the order of 18,000, 1,140 and 4 μmol m^?2 day^?1, respectively, and presumably sustain the high phytoplankton biomass observed in the cove during summer. The total amount of NO₃ ^? and SiO₄ ^4? supplied by SGD was higher than the measured inventories in the cove, while the reverse was true for PO₄ ^3?. These discrepancies are likely due to non-conservative biogeochemical processes that occur within the subterranean estuary and Alcalfar Cove waters.     

Reproductive biology of Philodryas patagoniensis (Snakes: Dipsadidae) in south Brazil: male reproductive cycle

The male reproductive cycle of Philodryas patagoniensis in south Brazil was described through morpho‐anatomical and histological analysis of individuals deposited in zoological collections. Spermatogenesis occurred during late autumn–winter (June–September) and spermiogenesis occurred in spring–summer (October–March). The volume of the testes was smaller (quiescent) in winter, while the tubular diameter and the epithelial height of the seminiferous tubule were larger in summer (January–March). The ductus deferens presented spermatozoa all over the year and had no seasonal variation in diameter. The length of the kidney was larger in winter–spring (July–December), although the tubular diameter and epithelium height of the sexual segment of the kidney (SSK) were larger only in winter (July–September). Total testicular regression was observed in late autumn (May), simultaneously with the peak in SSK. Therefore, at the individual level, males exhibit a discontinuous cyclical reproduction. Considering the population level, the reproductive cycle is seasonal semisynchronous, with most of the individuals showing a reproductive peak in spring–summer (October–March). Here, we present evidence to support the importance of the microscopic approach to reproductive cycle studies. Finally, we discuss the intrinsic and extrinsic factors influencing P. patagoniensis reproductive patterns.     

Pollen in aeolian dust with relation to allergy and asthma in Kuwait

The studying of spatial and temporal distribution of pollen is essential, but rarely tackled in the region including Kuwait. Pollen grains and aeolian dust in the state of Kuwait were seasonally monitored from August 2009 to August 2011 to identify and correlate spatially and temporally pollen data with human health asthma and allergy data. The year 2010–2011 yielded a high in deposited dust and pollen compared to 2009–2010 by 33.2 and 9.9%, respectively. The spring (April–May) and the autumn (October–November) seasons marked the most top pollen distribution for Chenopodiaceae, Gramineae (Poaceae), Cyperaceae, Fabaceae, and Plantaginaceae. The pollen graphs for summer (July–August) and winter (January–February) seasons showed low pollen distribution due to the severe drought, dust storms, winter wind and rainfall. There are no correlations found between pollen deposition and the number of asthma patients. The annual dust deposited rate in Kuwait during 2010/2011 was 373 t km^?2 which represented a 33.2% increase compared with 2009/2010. The study has concluded that pollen of Malvaceae, Compositae and Chenopodiaceae is the most common triggers of allergy in Kuwait. Additionally, a positive correlation between the number of allergy patients and deposited dust was observed during March 2010 and 2011.     

Comparative assessment of native,crossbred and exotic pigs during different seasons (winter,spring and summer) based on rhythmic changes in the levels of serum cortisol,lactate dehydrogenase levels and PBMC HSP70 mRNA expression pattern

The present study was conducted to ascertain the adaptive capability of pigs to different seasons based on changes in serum cortisol and lactate dehydrogenase (LDH) levels, and peripheral blood mononuclear cell (PBMC) heat shock protein 70 (HSP70) mRNA expression. Based on average THI, the seasons were classified as winter (November–February), spring (March–June), and summer (July–October). Hormone cortisol was found to be influenced by season (p < 0.01), age (p < 0.05), and genetics of the animal (p < 0.05). However, level of LDH was not influenced by either of these factors. HSP70 mRNA expression was higher in almost all age groups in crossbred and exotic pigs during summer in comparison to other seasons. Lower HSP70 gene expression was observed in almost all age groups of native pigs in comparison to crossbred and exotic during summer. In conclusion, native pigs were acclimatized for thermal stress in comparison to crossbred and exotic breeds of pigs. Also, the expression pattern of HSP70 gene is breed-specific, most likely due to variations in thermal tolerance and adaptation to different environmental conditions. Both serum cortisol and HSP70 gene may act as reliable biological markers for assessing the adaptive capabilities of pigs to different seasons.     

Reproductive biology of Rioraja agassizi from the coastal southwestern Atlantic ecosystem between northern Uruguay (34°S) and northern Argentina (42°S)

A total of 552 individuals of Rioraja agassizi (257 females and 295 males) were collected by bottom-trawl during research cruises. Sexual dimorphism was observed with females are heavier than males for a given total length (TL). Using logistic regression, it was determined that TL at 50% maturity of males was 475 mm TL and of females 520 mm TL. This estimation agrees with the morphological parameters measured. Although not statistically significant, a peak in reproductive activity was observed in males during late spring and summer. The monthly variation in the gonadosomatic index and oviducal gland width, together with the largest diameter of ovarian follicles, suggests that R. agassizi females have a partially defined annual reproductive cycle with two peaks, one from November (spring) to February (summer) and another in July (winter).     

Winter hatching in New England populations of invasive pheretimoid earthworms <Emphasis Type="Italic">Amynthas agrestis</Emphasis> and <Emphasis Type="Italic">Amynthas tokioensis</Emphasis>: a limit on population growth,or aid in peripheral expansion?

Some Asian megascolecid earthworms, e.g. Amynthas agrestis and Amynthas tokioensis, are highly invasive and have only recently been reported from natural ecosystems in the northeastern USA. There, they are annual earthworms that survive the winter as cocoons (an egg in a tough covering). Hatching occurs in mid-April when temperatures rise consistently above 10 °C. In some years, winter temperatures also reach 10 °C during short warming episodes, but hatchlings then are likely to die when temperatures drop again. To test this hypothesis, soil was collected on 7 sampling dates during January–May 2016 at one site in the Champlain Valley, Vermont and extracted for the cocoons. Both hatched and unhatched cocoons were enumerated and identified to species by both size and sequencing of the mitochondrial cytochrome c oxidase I gene (COI). A regression model on the number of unhatched cocoons over time predicted that ~ a quarter (A. agrestis) and ~ a third (A. tokioensis) would hatch before mid-May; no hatchlings were observed. Thus, hatching during warming periods in winter seemingly resulted in high mortality. Such winter hatching, and loss, may increase with climate warming in the region because winter warming periods should become more common. Climate warming could therefore reduce ability of the invasive earthworms to persist in northern habitats. Conversely, rapid hatching when the soil warms in spring could have an ecological benefit by allowing opportunities to expand at the thermal edge of the range as the climate continues to warm.     

Acclimation to UV radiation and antioxidative defence in the endemic Antarctic brown macroalga Desmarestia anceps along a depth gradient

The endemic Antarctic brown macroalga Desmarestia anceps colonizes the subtidal between 5 and 30 m in Potter Cove on King George Island (South Shetland Islands, Antarctica). Experiments were conducted to study photosynthetic activities, antioxidative enzymes and UV tolerance of field-grown individuals with respect to the light histories along different subtidal positions. Individuals collected from the upper (5.5 m) and mid-subtidal (9.0 m) are characterized by high maximum electron transport rates (ETRmax) measured by PAM-fluorometry and high activities of superoxide dismutase (SOD) supported by considerable activities of glutathione reductase. Individuals of this species from the upper subtidal are able to tolerate high irradiances of UV-B radiation because its photosynthetic apparatus is putatively well protected by phlorotannins. In contrast, individuals from lower subtidal positions (13.5 and 15.5 m) showed an opposite trend: lower ETRmax and SOD activities as well as a lower UV tolerance of photosynthesis. Moreover, a non-denaturing polyacrylamide gel electrophoresis (native PAGE) of a partially purified crude extract reveals that D. anceps has probably six isoforms of SOD. These intra-specific patterns imply a high phenotypical plasticity of D. anceps with respect to its photosynthesis and photoprotective mechanisms. Overall, photosynthesis, UV tolerance and antioxidative potential are highly regulated in D. anceps corresponding to the respective light regimes along its natural growth sites.     

Survival and growth of brown trout Salmo trutta L. embryos and the timing of hatching and emergence in two boreal lake outlet streams

Survival, growth and hatching of brown trout Salmo trutta embryos were studied using in situ incubation experiments in two lake outlet streams in Finland. The experimental design in both streams included an outlet site and a reference site far downstream. The date of hatching was recorded and the Elliott–Hurley model was then used to predict the time of emergence based on water temperature. For data analyses, the incubation period was divided into 'winter' (from fertilization to mid March) and 'spring' (from mid March until the end of the experiment). Temperature of the large-lake outlet remained at 1° C through the winter, while in other sites temperature was close to 0° C. In spring, temperature increased more slowly in the large-lake outlet. The survival of embryos was overall very high, from 83 to 98%, and they were larger in the outlets than in the downstream sites. Embryos hatched at the large-lake outlet in March, and 3–5 weeks later in the other sites. Although there were considerable between-site differences in hatching intervals, difference in expected 50% emergence dates of the earliest and latest site was only 4 days. Thus, any growth advantage that the outlet embryos had in winter disappeared by the end of the alevin period. Lake outlets, however, may be important for age 0 year brown trout later during the summer when other stream habitats do not provide adequate food resources.     

Sex steroids, growth and condition of Arctic charr broodstock during an annual cycle

Changes in plasma concentrations of sex steroids, growth rate and condition of repeat spawning (3+) male and female Arctic charr were studied throughout an annual reproductive cycle. Individually marked fish (mean weight approx. 500 g) were held under conditions of liberal food supply, constant temperature (4° C) and simulated natural photoperiod (Tromsø, 70° N). Once each month fish were weighed, measured and blood samples taken for steroid analysis. Plasma concentrations of testosterone (T), 11-ketotestosterone (11-KT) and oestradiol-17β (E₂) were determined using radioimmunoassay (RIA). Both male and female fish displayed distinct seasonal changes in plasma concentrations of sex steroids, growth rate and condition. From February (minimal concentrations) to March all sex steroids increased slightly and these elevated concentrations were maintained until May. Thereafter, there was a second, and far more pronounced, increase in plasma steroid concentrations which culminated in peak steroid concentrations in September–October. There was then a rapid decline during the spawning period. In winter, growth rate and condition were generally low, then increased during the spring, reached a peak during the summer, and then declined with the onset of autumn. During spring (March–May), the frequency distributions of plasma testosterone concentrations in both male and female fish were bimodal. The fish of the upper modal group of the distribution had significantly higher growth rates and condition than those in the lower modal group. In summer and early autumn (June–September) the association between T and growth rate changed. Significant negative correlations between T and growth rates were observed in females. There was an increase in endocrine activity, indicated by elevated plasma sex steroid concentrations in March, 7–8 months prior to maturation. It is suggested that this may be one factor influencing the onset of spring growth and energy deposition among maturing charr.     

The alien false limpet (Siphonaria pectinata) in the Bizerte channel (northern Tunisia): spawning,development and growth under laboratory conditions

Spawning, development and growth of Siphonaria pectinata in the laboratory were studied and described in detail during a one-year study period. Egg ribbons were observed in February, March, April, June, July, August and September, with a peak in number of ribbons per individual in July. On average, individuals laid 9.0 ± 5.1 egg ribbons at a spawning frequency of one egg ribbon day^?1. The number of eggs per ribbon ranged from 752 to 50,400 depending on ribbon length. Embryonic development studied in February (13–15 °C), April (15–17 °C) and July (25–27 °C), reached hatching within 8–16 days with average larval lengths of 76.7 ± 5.9, 83.0 ± 11.3 and 78.3 ± 9.0 μm, respectively. Massive mortality was registered a few days after hatching, with larval longevity depending on the study period. Larval settlement occurred within 36–38 days after hatching, but only in the spawn deposited in February. Larval growth was slow during the first three weeks (18–26 μm week^?1) and then accelerated until the sixth week (40–67 μm week^?1). The present study contributes knowledge on the spawning, development and growth of S. pectinata, an alien species recently spreading throughout the Tunisian coast.     

Predation of released pheasants <Emphasis Type="Italic">Phasianus colchicus</Emphasis> on lowland farmland in the UK and the effect of predator control

We present data accumulated over the last 25 years on predation of radio-tracked released pheasants. In studies of birds during the autumn/winter at six pheasant shoots with high-density releases managed by full-time gamekeepers, predation of released pheasants by foxes before the shooting season began (July–September) averaged 19.2?±?4.0% per site, and during the shooting season (October 1st–February 1st), a further 15.9?±?1.9% were predated. The range in 3-year average predation rates between sites before shooting began was 8.6 to 42.4%. At seven different sites during the spring and summer, between 20 and 71% of released or wild hens that survived the shooting season were predated, mainly by foxes, between mid-March and mid-July. Predation was significantly higher at sites with low-level predator control (59?±?4.7%) compared to those with high-level control (30?±?5.3%). At three of the four sites with low predator control between 5 and 22% of nest failures were caused by incubating hens being predated by foxes. Our data quantify for the first time highly variable predation rates of released pheasants before and during the winter shooting season which we suggest was influenced by a range of site and management factors. During the spring and summer, our data provide evidence that predation of adult hen pheasants as well as nest predation can suppress breeding success and that predator control can reduce these losses.