David E. Gaskin

Mercury Levels in Bonaparte's Gulls (Larus philadelphia) During Autumn Molt in the Quoddy Region, New Brunswick, Canada

No significant between sex differences were detected in Hg concentrations in primary feathers, pectoral muscle, brain, liver, and kidney tissues of fall migrating juvenile and second-year Bonapartes gulls (Larus Philadelphia) collected in the Quoddy region. Adults showed sexual differences only in the first 5 primary feathers, and in muscle, kidney and brain. Differences in Hg concentrations among age groups were reflected in the primary feathers and body tissues, but as the molt progressed, Hg concentrations decreased as they converged toward a minimum asymptotic Hg level for each tissue. This suggests that the body burden of Hg was reduced through its redistribution from the body tissues into the growing feathers. Mercury concentrations in premolt head feathers (pre-egg-laying) did not vary significantly between adult females and males, whereas Hg concentrations in postmolt feathers (post-egg-laying) were significantly lower in females, suggesting that egg-laying was also a route for Hg elimination. After the completion of the molt, the new feathers contained most of the body burden of Hg (93.0% in adults).

A mercury budget for the Bonaparte's gull during autumn moult

A bioenergetics-based budget which predicts net total Hg loss during the period of autumn moult was calculated for adult Bonapartes Gulls in the southwestern Bay of Fundy, Canada. Daily food consumption and, hence, ingestion of Hg measured in prey samples, was calculated from estimated energy requirements during the period of moult. The amount of Hg eliminated was estimated from analyses of Hg content in excreta and feathers. Elimination of Hg via the feathers accounted for 68% of the total loss from the body in females and 59% in males during the period of autumn moult. Actual loss from the body over time was estimated as the difference between measured maximum (premoult) and minimum (postmoult) body burden of total Hg. The measured net Hg loss from the body during the period of autumn moult was 23% lower than the predicted value for females and 49% higher than the predicted value for males. The negative and positive deviations of measured Hg losses from the predicted values for the separate sexes averaged out to within 6% of the predicted value when the sexes were pooled.

Changes in mercury levels in harbor porpoises from the Bay of Fundy, Canada, and adjacent waters during 1969–1977

Mercury levels were studied in a sample of 146 harbor porpoises taken in the Bay of Fundy, Canada, and adjacent waters during 1969–77. Mean concentrations of total mercury recorded in 5-year old males (exemplifying sexually mature adults) were 1.12 ppm in axial muscle, 0.38 in cerebrum, 0.31 in cerebellum, 2.00 in kidney, and 15.7 in liver. Respective means in tissues of 5-year old females were 1.46, 0.42, 0.21 2.77 and 16.2 ppm. There was a clear correlation of increase in total Hg with age in the tissues examined. Except in the liver, mercury levels were less well correlated with weight and body length than with age. Hg levels were not significantly correlated (p > 0.05) with weight and lengthwithin age classes, except marginally in the case of liver (P ⩾0.10). Hg in muscle was virtually all in the methylated form, but in liver only about 17% was methylated. The proportions in other tissues were intermediate (kidney about 41%, mam-mary gland about 46%, brain about 8 to 52%). Levels in liver were thought to be those giving the best indication of changes in background levels of mercury in the food chain. Significant changes in Hg tissue levels appear to have occurred during the 9-year study period. Liver Hg levels in both sexes decreased from 1970 to 1971, remained low for 3 years, increased again in 1974, and continued to do so in the years following. Data are presented suggesting that this also occurred in other tissues. Since there is no evidence of a change in diet in this period, we speculate that the decline in Hg levels could be correlated with a dominance of relatively mercury-poor Gulf Stream water in the Bay of Fundy approaches in 1971–73, as opposed to the usual dominance by waters of the Nova Scotia current.

Polychlorinated biphenyls in harbor porpoisesPhocoena phocoena (L.) from the Bay of Fundy, Canada and adjacent waters, with some information on chlordane and hexachlorobenzene levels

Polychlorinated biphenyl (PCBs) levels were measured in tissues from harbor porpoises collected during 1971–77 from the Bay of Fundy (Canada) and adjacent waters. Levels of chlordanes and hexachlorobenzene (HCB) were measured in smaller numbers of the same series of specimens from 1975–77. PCB levels were relatively high in all tissues of sexually immature specimens of both sexes as well as adult males, and relatively low in adult females. The maximum level in blubber was 310 ppm; in other tissues, commensurate with their lower fat content, maxima were rarely more than 2 ppm. PCB levels in blubber, liver, and kidney were correlated with one another. No discernible changes in mean levels between 1971–77 were detected, nor were significant regional differences recognized within the Bay of Fundy, or among specimens obtained between Newfoundland and Rhode Island. Levels increased significantly with age in all tissues from males, and decreased significantly in most tissues from females; individual variation was large. Particularly high levels in four-year old males and three-year old females were related to a growth spurt at puberty with correspondingly elevated food (and hence PCB) intake per unit of time. Chlordanes were present in most tissues, with a maximum of 14 ppm in blubber. Only small quantities (0.12 to 0.43 ppm) of HCB were recorded; the maximum was only 0.43 ppm in blubber, but levels of HCB were strongly correlated with respective PCB levels in the same tissues.

Morphometric and meristic comparisons of skulls of harbour porpoise Phocoena Phocoena (L.) from the North Atlantic and North Pacific

Abstract Highly significant (α = 0.01) differences in analysis of 473 skulls of harbour porpoises indicate separate eastern Pacific, western Atlantic, and eastern Atlantic populations. Including the isolated population in the Black Sea—Sea of Azov, four major populations in this species are presently definable. Small sample sizes and incomplete data prevented conclusive tests for significant differences in subpopulations within these, but there are trends which suggest some segregation of Dutch, Baltic, and eastern English (North Sea) animals might be demonstrated with large samples. Skulls of western Atlantic harbour porpoises are larger than those of eastern Atlantic animals; skulls of eastern Pacific porpoises are smaller yet. This size order is more strongly marked in males than females. Despite their smallest overall dimensions, Pacific harbour porpoise skulls are most attenuate, with significantly longer jaws and more teeth than Atlantic animals. Females exceed males in size in each population. The ...

Organochlorine levels in North Atlantic right whale (Eubalaena glacialis) blubber

Polychlorinated biphenyls (PCBs), total DDT (DDT+DDE+DDD), dieldrin, heptachlor epoxide, chlordanes, and hexachlorobenzene (HCB) were found in blubber biopsies from endangered North Atlantic right whales (Eubalaena glacialis) in the Bay of Fundy and on Browns-Baccaro Banks. Analyses included four sex and age class composite samples from 1988, and 21 individual samples from 1989. Generally, PCBs demonstrated the highest wet weight residue levels (up to 1.9 μg/g), followed by total DDT (DDT+DDE+DDD) (trace to 0.47 μg/g). Relatively low residue levels in adult females suggest that transmammary organochlorine (OC) residue transfer occurs during lactation. The actual blubber residue loads may have been under-estimated, because the samples were taken when the whales were depositing fat reserves and the samples may not have been representative of the remainder of the blubber.

An environmental index for habitat utilization by female harbour porpoises with calves near Deer Island, Bay of Fundy

Abstract The Bay of Fundy is a known area of concentration of Phocoena phocoena during the summer months. In this study, 698 females with calves and 5 473 porpoises of other social status were sighted during 1 858 hours of observation from July–September 1970–1977. It was noted that segregation of mother-calf pairs occurred in certain sectors of the study area. To evaluate habitat utilization by mother-calf pairs, a numerical index was developed which evaluated information on 12 physical and biological factors such as water temperature, current velocity, bottom depth and food availability as indicated by the level of secondary productivity. Statistical analysis revealed a significant (p < 0.001) relationship between uncorrected sightings per unit effort (S/UE) for mother-calf pairs and the habitat index. It is suggested that a complex interaction of physical and biological factors influences the distribution of mother-calf pairs. There were no strong correlations between S/UE values and individual index c...

Revision of the New Zealand Crambini (Lepidoptera: Pyralidae: Crambinae)

The New Zealand species of Crambini trib. redef. are treated; 55 species (1 adventive) are considered valid. Thirty‐five species previously in Chilo, Crambus, Hypochalcia, or Tauroscopa are transferred to Orocrambus Purdie, 1884: abditus, aethonellus, angustipennis, apicellus, callirrhous, clarkei eximia, corruptus, crenaeus, cyclopicus, dicrenellus, enchophorus, ephorus, flexuosellus, fugitivellus, haplotomus, harpophorus, heliotes, heteraulus, horistes, isochytus, lectus, melitastes, oppositus, ornatus, paraxenus, punctellus, ramosellus, scutatus, simplex, siriellus, sophronellus, tuhualis, vittellus, vulgaris, and xanthogrammus. Five new species are described under Orocmmbus: jansoni, lewisi, lindsayi, ordishi, and philpotti. Ten accepted species of Orocrambus are re‐examined: catacaustus, clarkei clarkei, cultus (of which no specimens now exist), machaeristes, melampetrus (type species), mylites, scoparioides, thymiastes, tritonellus, and ventosus. Sixteen new synonymies are made under Orocrambus: Cra...

Partitioning of cadmium and lead within seston of coastal marine waters of the Western Bay of Fundy, Canada

Seston samples were collected at 42 surface stations located in the Quoddy Region, New Brunswick, Canada. In an attempt to separate ecologically important components, the seston samples were divided into two size fractions: 20 to 64 μm and 0.7 to 20 μm. Particulate organic carbon, particulate aluminum, chlorophyll a, particulate cadmium, and particulate lead concentrations were determined for both size fractions. Cadmium was found to be associated almost entirely with the organic detrital component of the seston, for both size fractions. In contrast, lead was associated with several seston components. For the 20 to 64 μm size fraction, lead was partitioned between the organic detrital and suspended clay aggregate components of the seston. Within the 0.7 to 20 μm fraction, lead was partitioned, in descending order of importance, between the organic detrital, suspended clay aggregate, and phytoplankton components. These partitioning characteristics of the two metals were used to predict accumulation trends of cadmium and lead in the calanoid copepod species which form the primary consumer level of the marine food web of the Quoddy Region.

Information on the life cycles of some New Zealand Crambini (Lepidoptera: Pyralidae: Crambinae)

Data are presented on the life cycles and larval behaviour of 10 species of New Zealand Crambini of the genus Orocrambus Purdie: O. angustipennis (Zeller), O. apicellus (Zell.), O. corruptus (Butler), O. cyclopicus (Meyrick), O. enchophorus (Meyr.), O. flexuosellus (Doubleday), O. heliotes (Meyr.), O. ramosellus (Dbld.), O. simplex (Btlr), and O. vittellus (Dbld.). Tabular comparisons of egg size, shape, and colour, durations of larval and pupal instars, and adult flight periodicity are given.