45 research outputs found
Emerging patterns of species richness, diversity, population density, and distribution in the skates (Rajidae) of Alaska
Six years of bottom-trawl survey data, including over 6000 trawls covering over 200 km2 of bottom area throughout Alaska’s subarctic marine waters, were analyzed for patterns in species richness, diversity, density, and distribution of skates. The Bering Sea continental shelf and slope, Aleutian Islands, and Gulf of Alaska regions were stratified by geographic subregion and depth. Species richness and relative density of skates increased with depth to the shelf break in all regions. The Bering Sea shelf was dominated by the Alaska skate (Bathyraja parmifera), but species richness and diversity were low. On the Bering Sea slope, richness and diversity were higher in the shallow stratum, and relative density appeared higher in subregions dominated by canyons. In the Aleutian Islands and Gulf of Alaska, species richness and relative density were generally highest in the deepest depth strata. The data and distribution maps presented here are based on species-level data collected throughout the marine waters of Alaska, and this article represents the most comprehensive summary of the skate fauna of the region published to date
Estrous expression of sows after altered suckling and boar exposure
In two different experiments, we studied the influence of: 1) separating litters from their dams (altered suckling) during the last 8 days of lactation, which included a change in housing and social interaction with other sows; 2) providing boar exposure (1 hr/d); and 3) parity on the ability of sows to come into heat during lactation and after weaning. Our studies indicated that: 1) 6 hr of altered suckling and 1 hr of boar exposure may shorten the interval to heat for sows that express estrus during lactation, but 3 hr of altered suckling and 1 h of boar exposure are sufficient to induce estrus in 65 to 79% of the sows; 2) boar exposure (1 hr /day) of sows is not sufficient to induce estrus during lactation; 3) pre weaning boar exposure (1 hr/day) reduced intervals to heat after weaning; and 4) breed composition and season may alter the responsiveness of sows to treatments that induce estrus during lactation and after weaning.; Swine Day, Manhattan, KS, November 19, 198
Estrous synchronization and scheduled artificial insemination for gilts
Gilts were artificially inseminated on the fifth, sixth and seventh days after estrous synchronization with altrenogest (scheduled AI). Contemporary controls also were synchronized but were checked for estrus twice daily. Scheduled AI gilts had farrowing rates and litter sizes similar to controls. Altrenogest is not presently available to pork producers but these results suggest that it could be used in combination with artificial insemination to schedule breeding according to a predetermined schedule.; Swine Day, Manhattan, KS, November 10, 198
Fertility with artificial insemination: gilts that lock on the insemination spirette vs. those that don\u27t
KSU breeding records show a higher farrowing rate for gilts that lock on the insemination spirette at both inseminations as opposed to gilts that lock at one insemination or at neither insemination. Continued research is focusing on factors affecting female response to insemination and fertility.; Swine Day, Manhattan, KS, November 11, 198
Observer-reported skate bycatch in the commercial groundfish fisheries of Alaska
We analyzed skate catch data collected by observers in the
North Pacific Groundfish Observer Program (NPGOP) from 1998 through 2008 to document recent changes in the identification of skates by observers and to examine the species composition of observed skate catch in Alaska’s groundfish fisheries as well as recent trends in skate retention by commercial fishermen. Historically, almost all skate bycatch has been reported by NPGOP observers as
“skate unidentified.” However, since 2004 observers have been trained to identify skates to the genus and species
level. In 2008 over 95% of all skates were identified at least to the genus level, and over 50% were identified
to species. The most common species of skates identified by observers in groundfish fisheries are Bathyraja parmifera (Alaska skate), Raja binoculata (big skate), and Bathyraja
aleutica (Aleutian skate). Species composition of reported skate catch generally reflects recent survey-derived
biomass estimates, with B. parmifera dominating the catches in the Bering Sea and, to a lesser extent, in the Aleutian Islands region, and species of the genus Raja dominating catches in the Gulf of Alaska. A relatively high percentage of the skate catch on longline vessels is still reported
at the family or genus level because of difficulties in the identification of skates not brought onboard the vessel. For the larger skate species, the proportion retained for processing has increased in recent years as the market price for skate product has increased. Although observed skate catch does not give a complete account of skate bycatch in the fisheries of the region, observer data provide critical information for the appropriate management of skate populations in
Alaska
Bathyraja panthera, a new species of skate (Rajidae: Arhynchobatinae) from the western Aleutian Islands, and resurrection of the subgenus Arctoraja Ishiyama
We provide morphological and molecular evidence to recognize a new species of skate from the North Pacific, Bathyraja panthera. We also resurrect the skate subgenus Arctoraja Ishiyama, confirming its monophyly and the validity of the subgenus. Arctoraja was previously
recognized as a distinct subgenus of Breviraja and later synonymized with Bathyraja (family Rajidae). Although the nominal species of Arctoraja have all been considered synonyms of Bathyraja parmifera by various authors, on the basis of morphometric, meristic, chondrological, and molecular data we recognize four species, including the new species. Species of Arctoraja are distributed across the North Pacific Ocean and adjacent seas from southern Japan to British Columbia. Bathyraja parmifera is abundant in the eastern Bering Sea, Aleutian Islands, and northern Gulf of Alaska; B. smirnovi is a western Pacific species found in the Sea of Okhotsk and Sea of Japan; B. simoterus is restricted to waters around the northern and eastern coasts of Hokkaido, Japan; and the new species B. panthera is
restricted to the western Aleutian Islands. Bathyraja panthera is diagnosed by its color pattern of light yellow blotches with black spotting on a greenish brown background, high thorn and vertebral counts, chondrological characters of the neurocranium and clasper, and a unique nucleotide sequence within the mitochondrial cytochrome oxidase gene. Furthermore, the species presently recognized as Bathyraja parmifera exhibits two haplotypes among specimens from Alaska, suggesting the possibility of a second, cryptic species
The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study
AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease