DDE residues and eggshell changes in Alaskan falcons and hawks

Eggshell thickness after exposure to DDT was reduced by 21.7 percent in Alaskan tundra peregrines, by 16.8 percent in taiga peregrines, by 7.5 percent in Aleutian peregrines, by 3.3 percent in rough-legged hawks, and not at all in gyrfalcons. Tundra peregrine eggs contain an average of 889 parts of DDE per million (lipid basis); taiga peregrine eggs contain 673 parts per million; Aleutian peregrine eggs contain 167 parts per million; rough-legged hawk eggs contain 22.5 parts per million; and gyrfalcon eggs contain 3.88 parts per million. These changes in eggshell thickness and the pesticide residues reflect different degrees of exposure to contamination. There is a highly significant negative correlation between shell thickness and DDE content in peregrine eggs. Tundra and taiga peregrines have fledged progressively fewer young each year since 1966.     

Underwater video analysis as a non‐destructive alternative to electrofishing for sampling imperilled headwater stream fishes

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China's distant‐water fisheries in the 21st century

We conservatively estimate the distant‐water fleet catch of the People's Republic of China for 2000–2011, using a newly assembled database of reported occurrence of Chinese fishing vessels in various parts of the world and information on the annual catch by vessel type. Given the unreliability of official statistics, uncertainty of results was estimated through a regionally stratified Monte Carlo approach, which documents the presence and number of Chinese vessels in Exclusive Economic Zones and then multiplies these by the expected annual catch per vessel. We find that China, which over‐reports its domestic catch, substantially under‐reports the catch of its distant‐water fleets. This catch, estimated at 4.6 million t year^?1 (95% central distribution, 3.4–6.1 million t year^?1) from 2000 to 2011 (compared with an average of 368 000 t·year^?1 reported by China to FAO), corresponds to an ex‐vessel landed value of 8.93 billion € year^?1 (95% central distribution, 6.3–12.3 billion). Chinese distant‐water fleets extract the largest catch in African waters (3.1 million t year^?1, 95% central distribution, 2.0–4.4 million t), followed by Asia (1.0 million t year^?1, 0.56–1.5 million t), Oceania (198 000 t year^?1, 144 000–262 000 t), Central and South America (182 000 t year^?1, 94 000–299 000 t) and Antarctica (48 000 t year^?1, 8 000–129 000 t). The uncertainty of these estimates is relatively high, but several sources of inaccuracy could not be fully resolved given the constraints inherent in the underlying data and method, which also prevented us from distinguishing between legal and illegal catch.     

Chromosomal evaluation of a ewe lamb with atresia ani vaginalis

Chromosomes of a ewe lamb born with atresia ani vaginalis were examined after a 72-hour culture of peripheral whole blood. The 2n number of chromosomes was 54,XX, with no apparent deviation from normality. Pedigree analysis of the ewe lamb indicated that her sire and dam were only slightly related (Rsd = 0.59%); therefore, the amount of inbreeding of the lamb was small (Fx = 0.30%).     

Ploidy reduction in blackberry

Polyploidy in blackberries and ploidy differences between Rubus species are obstacles to the efficient introduction of valuable germplasm, both intra- and interspecific, into blackberry breeding programs. Expansion of the germplasm base would be facilitated by reducing the ploidy level of blackberry cultivars to the diploid level. In this report selection of twin seed, interspecific hybridization, and pollen irradiation were compared as methods in the recovery of dihaploids from tetraploid blackberry cultivars. One dihaploid was obtained through selection of twin seed and several were obtained following interspecific hybridization. The infrequency of twinning and difficulty in detecting twin seed in Rubus reduced the efficiency of this method. The efficiency with which dihaploids could be obtained following interspecific hybridization varied with the pollen parent. Reduced seed set and seed quality following pollinations with respectively R. parvifolius and R. hirsutus could be used to advantage in the recovery of dihaploids from blackberries. Ploidy reduction in several tetraploid blackberry cultivars was obtained following pollinations with 100 and 150 kR gamma irradiated pollen. Most of the seedlings obtained at the 50 kR dosage were aneuploid. Pollen irradiation at 150 kR was the most efficient method of obtaining dihaploids from tetraploid blackberries. Twenty percent of the seedlings obtained following this treatment were dihaploid.