Fat reserves and condition indices in greater snow geese

We evaluate several external condition indices as predictors of total fat reserves (TFR) in greater snow geese. In 1979 and 1980, we collected 373 adult geese during their spring staging halt along the St. Lawrence estuary, Québec, and determined their fat content by ether extraction. Body weight (BW) alone and BW divided by various morphometric measurements are relatively poor predictors of TFR (maximum r2 = 0.56). The thickness of subcutaneous fat (measured externally with an adiposimeter) combined with BW is the best predictor of TFR (R2 = 0.65). This condition index can be useful in predicting the average condition of living geese, provided a reasonable sample size is available. We also examined some internal condition indices. Of these, the dry weight of abdominal fat is the easiest to apply and one of the most reliable (r2 = 0.86).

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Mercury in Marine Mussels from the St. Lawrence Estuary and Gulf (Canada): A Mussel Watch Survey Revisited after 40 Years

Applied Sciences ◽

10.3390/app10217556 ◽

2020 ◽

Vol 10 (21) ◽

pp. 7556

Author(s):

Daniel Cossa ◽

Anne-Marie Tabard

Keyword(s):

Soft Tissue ◽

Shell Length ◽

Dry Weight ◽

Distribution Patterns ◽

Contamination Level ◽

Lawrence Estuary ◽

Tissue Weight ◽

Marine Mussels ◽

Biotic Effects ◽

St Lawrence Estuary

Various species of marine mussels have been used, in the last 50 years, as sentinel organisms for monitoring metal contamination along marine coasts. There are two main reasons for this: these mollusks concentrate metals in their soft tissue and they are geographically widespread. In practice, trace metal concentrations in mussel soft tissue reveal (after some correction for biotic effects) the contamination level of their surrounding environment. We present the results of a mercury (Hg) survey in Mytilus spp. collected in the summers of 2016, 2018, and 2019 at 51 stations distributed along the coasts of the Estuary and Gulf of St. Lawrence. Mercury concentrations ranged from 0.063 to 0.507 µg g−1 (dry weight, dw), with a grand mean of 0.173 ± 0.076 µg g−1 dw (±1 standard deviation), and a median of 0.156 µg g−1 dw for the 504 individuals analyzed. Mercury contents per individual mussel were significantly (p < 0.01) related to shell length and dry tissue weight, with the smaller individuals having the highest Hg concentrations. To take into account these biotic effects, we normalized Hg concentrations of the mussel soft tissue for constant shell length (L) and soft tissue weight (TW) based on the log-log relationships between Hg content and L or TW. The normalized Hg contents of mussels varied from 10.9 to 66.6 ng per virtual individual of 35 mm length and 0.17 g dry weight. A similar normalization procedure applied to 1977–1979 data, yielded a very similar range: 12 to 64 ng. This observation suggests that the Hg bioavailable to marine mussels in the study area did not change over a span of 40 years. Regional Hg distribution patterns indicate a gradual decrease of Hg content in mussels downstream from freshwater discharges to the St. Lawrence Estuary and the Baie des Chaleurs, suggesting that rivers constitute a significant Hg source in these estuarine systems. Atmospheric Hg deposition and concentration in marine waters of the Atlantic Ocean are known to have decreased in the last decades. However, in coastal environments, the response to these changes does not seem to be rapid, probably because of the long residence time of Hg in soils before being exported to coastal areas.

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Dynamics of fat and protein reserves during winter and spring migration in greater snow geese

Canadian Journal of Zoology ◽

10.1139/z92-280 ◽

1992 ◽

Vol 70 (11) ◽

pp. 2077-2087 ◽

Cited By ~ 48

Author(s):

Gilles Gauthier ◽

Jean-François Giroux ◽

Jean Bédard

Keyword(s):

Spring Migration ◽

The Arctic ◽

Late Winter ◽

Lawrence Estuary ◽

Chen Caerulescens ◽

Protein Storage ◽

Fat Reserves ◽

Snow Geese ◽

Chen Caerulescens Atlantica ◽

St Lawrence River

We studied the dynamics of fat and protein reserves in greater snow geese (Chen caerulescens atlantica) during winter and spring migration, and examined the influence of a recent expansion of their staging grounds and change in habitat use on fat and protein storage. We collected 63 geese during the winter of 1989–1990 at Bombay Hook National Wildlife Refuge in Delaware, 158 geese in spring 1989 and 1990 at Lake Saint-Pierre and Cap-Saint-Ignace along the St. Lawrence River in southern Quebec, and 17 geese at the end of the 1990 migration on By lot Island, N.W.T. In both sexes, protein reserves did not change in winter but fat declined from a peak in December to a low point in early March, just before spring migration. Geese collected 3 weeks later at Lake Saint-Pierre (800 km north) had considerably larger fat reserves (90% larger in females and 40% in males). Geese accumulated large fat reserves at both sites along the St. Lawrence River. Although geese staged for a shorter period at Lake Saint-Pierre (a recently used area), males stored as much fat as those staging at Cap-Saint-Ignace and females only slightly less. A small amount of protein was stored between late winter and the end of staging. Spring conditioning of geese along the St. Lawrence River seems to have improved over the past decade. We found weak evidence that larger females stored more fat. The cost of migrating from the St. Lawrence to Arctic nesting grounds (2900 km) is considerable, as half of the fat reserves accumulated in spring were used for the migration. There is no evidence of fat or protein storage between the St. Lawrence estuary and the Arctic nesting grounds.

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The challenges of a small population exposed to multiple anthropogenic stressors and a changing climate: the St. Lawrence Estuary beluga

Polar Research ◽

10.33265/polar.v40.5523 ◽

2021 ◽

Vol 40 ◽

Author(s):

Véronique Lesage

Keyword(s):

Harmful Algal Blooms ◽

Algal Blooms ◽

Extinction Risk ◽

Small Population ◽

Ecosystem Structure ◽

Toxic Substances ◽

Natal Philopatry ◽

Lawrence Estuary ◽

Fat Reserves ◽

St Lawrence Estuary

Until 2012, the St. Lawrence Estuary beluga population was considered stable with about 1100 individuals. An abnormally high number of calves reported dead that year triggered a population status reassessment. This review article summarizes the findings from this reassessment and various studies subsequent to it and provides an updated analysis of carcass recovery rates up to 2019. The 2013 review indicated a decreased incidence of cancer in adults, suggesting positive impacts from the regulation of toxic substances (e.g., PCBs and PAHs). However, the review also revealed that the population initiated a decline of ca. 1% per year in the early 2000s and had reached a size of ca. 900 individuals by 2012. This decline was accompanied by high inter-annual variability in calf survival and pregnancy rates and by more frequent peripartum complications among dead females. The change in population dynamics coincided with a shift in the St. Lawrence ecosystem structure and warmer environmental conditions, suggesting a link through effects on reproductive success and adult female body condition. This was supported by the continued high calf mortality after 2012 and a documented decline of fat reserves in beluga blubber from 1998 to 2016. Other factors, such as the exposure to chronic vessel noise, increasing whale-watching activities, high contaminant levels and episodic harmful algal blooms, may also be contributing to the long-term non-recovery and current decline of the population. The strong natal philopatry and complex social system of the beluga likely increase its vulnerability to extinction risk by limiting dispersal.

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Flock composition and foraging behavior of greater snow geese (Chen caerulescens atlantica)

Canadian Journal of Zoology ◽

10.1139/z92-323 ◽

1992 ◽

Vol 70 (12) ◽

pp. 2410-2415 ◽

Cited By ~ 8

Author(s):

Luc Bélanger ◽

Jean Bédard

Keyword(s):

Social Status ◽

Foraging Behavior ◽

Foraging Strategy ◽

Behavioral Differences ◽

Lawrence Estuary ◽

Chen Caerulescens ◽

Plant Parts ◽

Snow Geese ◽

Chen Caerulescens Atlantica ◽

St Lawrence Estuary

We studied the foraging behavior of greater snow geese (Chen caerulescens atlantica) staging in a Scirpus tidal marsh along the St. Lawrence Estuary in Quebec during fall 1985 and 1986 and spring 1986 and 1987. Among all foraging activities, grubbing (feeding on underground plant parts) ranked first (>50%), but important seasonal differences were observed. Geese spent less time grubbing and more time searching and grazing on newly emerging shoots in spring than in fall. Our study also revealed differences in the foraging behaviors of birds of differing social status. We found that juveniles spent more time searching for food than adults, particularly in fall. Males also spent more time alert than females, at least in fall. We also observed behavioral differences among adults of different social status (member of a family, paired bird, and unpaired bird). Solitary unpaired birds devoted less time grubbing and, consequently, more time searching for food, than paired birds in fall. Finally, paired and family-member adult birds adopted a similar foraging strategy, spending more time searching and grazing in spring than in fall.

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The Effects of Grazing by Greater Snow Geese on the Vegetation of Tidal Marshes in the St Lawrence Estuary

Journal of Applied Ecology ◽

10.2307/2403980 ◽

1987 ◽

Vol 24 (3) ◽

pp. 773 ◽

Cited By ~ 32

Author(s):

J.-F. Giroux ◽

J. Bedard

Keyword(s):

Tidal Marshes ◽

Lawrence Estuary ◽

Snow Geese ◽

St Lawrence Estuary

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Temporal variability of zooplankton biomass (ATP content and dry weight) in the St. Lawrence Estuary: Advective phenomena during neap tide

Marine Biology ◽

10.1007/bf00392250 ◽

1983 ◽

Vol 73 (3) ◽

pp. 247-255 ◽

Cited By ~ 6

Author(s):

Y. Maranda ◽

G. Lacroix

Keyword(s):

Temporal Variability ◽

Neap Tide ◽

Dry Weight ◽

Zooplankton Biomass ◽

Atp Content ◽

Lawrence Estuary ◽

St Lawrence Estuary

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Relationship of Condition Index and Reproductive Status of Black Snail, Fannus ater in Merchang Lagoon

Universiti Malaysia Terengganu Journal of Undergraduate Research ◽

10.46754/umtjur.v2i1.98 ◽

2020 ◽

Vol 2 (1) ◽

pp. 1-8

Author(s):

Nurul Husna Hassan ◽

Roslizawati Ab Lah

Keyword(s):

Biological Activities ◽

Gonadosomatic Index ◽

Dry Weight ◽

Condition Index ◽

Abundant Species ◽

Reproductive Status ◽

Future Research ◽

Weight Measurement ◽

Significant Difference ◽

Condition Indices

Black snail, Faunus ater is an abundant species in Malaysia yet not many research have focused on its physiological and biological activities. This research aimed to assess the condition index (CI) and reproductive status based on the gonadosomatic index (GSI) for short-term duration. Samples were collected monthly from Merchang Lagoon, from November 2018 to January 2019. Four different types of condition indices equation were applied in this study and the results revealed that there were significant differences between four equations for measuring the CI (P=0.000). However, the result for the GSI shows no significant difference between three month of sampling (P>0.05). CI based on fresh weight measurement (Fww/Tww x 100) and dry weight measurement (Fdw/Fww x 100) reached its peak when GSI decreased. The rest of the trend for CI fluctuated and CI was not affected by GSI. Overall, this study concluded that, there were trends observed in CI and GSI for the black snails. However, it is suggested that longer term observation in future research is needed have a better understanding on the black snails.

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Visceral fat obesity is the key risk factor for the development of reflux erosive esophagitis in 40–69-years subjects

Esophagus ◽

10.1007/s10388-021-00859-5 ◽

2021 ◽

Author(s):

Shinya Ohashi ◽

Takahisa Maruno ◽

Keita Fukuyama ◽

Osamu Kikuchi ◽

Tomohiko Sunami ◽

...

Keyword(s):

Risk Factor ◽

Visceral Fat ◽

Subcutaneous Fat ◽

Erosive Esophagitis ◽

Smoking History ◽

Related Factors ◽

Visceral Fat Area ◽

Daily Alcohol Intake ◽

Gastrointestinal Reflux ◽

Total Fat

Abstract Background Visceral fat obesity can be defined quantitatively by abdominal computed tomography, however, the usefulness of measuring visceral fat area to assess the etiology of gastrointestinal reflux disease has not been fully elucidated. Methods A total of 433 healthy subjects aged 40–69 years (234 men, 199 women) were included in the study. The relationship between obesity-related factors (total fat area, visceral fat area, subcutaneous fat area, waist circumference, and body mass index) and the incidence of reflux erosive esophagitis was investigated. Lifestyle factors and stomach conditions relevant to the onset of erosive esophagitis were also analyzed. Results The prevalence of reflux erosive esophagitis was 27.2% (118/433; 106 men, 12 women). Visceral fat area was higher in subjects with erosive esophagitis than in those without (116.6 cm2 vs. 64.9 cm2, respectively). The incidence of erosive esophagitis was higher in subjects with visceral fat obesity (visceral fat area ≥ 100 cm2) than in those without (61.2% vs. 12.8%, respectively). Visceral fat obesity had the highest odds ratio (OR) among obesity-related factors. Multivariate analysis showed that visceral fat area was associated with the incidence of erosive esophagitis (OR = 2.18), indicating that it is an independent risk factor for erosive esophagitis. In addition, daily alcohol intake (OR = 1.54), gastric atrophy open type (OR = 0.29), and never-smoking history (OR = 0.49) were also independently associated with the development of erosive esophagitis. Conclusions Visceral fat obesity is the key risk factor for the development of reflux erosive esophagitis in subjects aged 40–69 years.

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Benthic fluxes of dissolved organic nitrogen in the lower St. Lawrence estuary and implications for selective organic matter degradation

Biogeosciences ◽

10.5194/bg-10-7609-2013 ◽

2013 ◽

Vol 10 (11) ◽

pp. 7609-7622 ◽

Cited By ~ 13

Author(s):

M. Alkhatib ◽

P. A. del Giorgio ◽

Y. Gelinas ◽

M. F. Lehmann

Keyword(s):

Organic Matter ◽

Dissolved Organic Nitrogen ◽

Organic Nitrogen ◽

Bottom Water ◽

Estuarine Sediments ◽

Internal Source ◽

Lawrence Estuary ◽

Element Partitioning ◽

Sediment Porewaters ◽

St Lawrence Estuary

Abstract. The distribution of dissolved organic nitrogen (DON) and carbon (DOC) in sediment porewaters was determined at nine locations along the St. Lawrence estuary and in the gulf of St. Lawrence. In a previous manuscript (Alkhatib et al., 2012a), we have shown that this study area is characterized by gradients in the sedimentary particulate organic matter (POM) reactivity, bottom water oxygen concentrations, and benthic respiration rates. Based on the porewater profiles, we estimated the benthic diffusive fluxes of DON and DOC in the same area. Our results show that DON fluxed out of the sediments at significant rates (110 to 430 μmol m−2 d−1). DON fluxes were positively correlated with sedimentary POM reactivity and varied inversely with sediment oxygen exposure time (OET), suggesting direct links between POM quality, aerobic remineralization and the release of DON to the water column. DON fluxes were on the order of 30 to 64% of the total benthic inorganic fixed N loss due to denitrification, and often exceeded the diffusive nitrate fluxes into the sediments. Hence they represented a large fraction of the total benthic N exchange, a result that is particularly important in light of the fact that DON fluxes are usually not accounted for in estuarine and coastal zone nutrient budgets. In contrast to DON, DOC fluxes out of the sediments did not show any significant spatial variation along the Laurentian Channel (LC) between the estuary and the gulf (2100 ± 100 μmol m−2 d−1). The molar C / N ratio of dissolved organic matter (DOM) in porewater and the overlying bottom water varied significantly along the transect, with lowest C / N in the lower estuary (5–6) and highest C / N (> 10) in the gulf. Large differences between the C / N ratios of porewater DOM and POM are mainly attributed to a combination of selective POM hydrolysis and elemental fractionation during subsequent DOM mineralization, but selective adsorption of DOM to mineral phases could not be excluded as a potential C / N fractionating process. The extent of this C- versus N- element partitioning seems to be linked to POM reactivity and redox conditions in the sediment porewaters. Our results thus highlight the variable effects selective organic matter (OM) preservation can have on bulk sedimentary C / N ratios, decoupling the primary source C / N signatures from those in sedimentary paleoenvironmental archives. Our study further underscores that the role of estuarine sediments as efficient sinks of bioavailable nitrogen is strongly influenced by the release of DON during early diagenetic reactions, and that DON fluxes from continental margin sediments represent an important internal source of N to the ocean.

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