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91.
The brain and eyes from a 1-day-old, male mixed-breed lamb with bilateral microphthalmia were examined. Bilateral ventral colobomata of choroid, sclera, retina and optic nerve were accompanied by agenesis of the optic nerve, and dilated lateral and third ventricular cavities that communicated with the subarachnoid space. Abundant neuroretinal tissue extending through the colobomatous defect to retro-orbital connective tissue, the meningeal surface and ventricular system were identified by histologic examination. Positive immunolabeling of these structures for recoverin (a photoreceptor marker) established the retinal origin of ectopic structures. The optic nerve was replaced by a short fibrous stalk containing glial nests. Sections of brainstem revealed extensive architectural disorganization. A developmental abnormality resulting from defective optic nerve and retina compartmentalization, accompanied by abnormalities of midline development consistent with the holoprosencephaly syndrome, was diagnosed. These lesions are consistent with signaling defects in the sonic hedgehog signaling pathway. Genetic and toxic causes of sonic hedgehog signaling defects are discussed. 相似文献
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Caroline Ritter Annabelle Beaver Marina A. G. von Keyserlingk 《Reproduction in domestic animals》2019,54(Z3):29-37
Using reproduction parameters as indicators for cattle welfare has limitations and, at best, these parameters should only be viewed as indirect indicators of welfare. On a farm level, measures such as fertility rates emphasize biological performance of the herd but fail to consider the welfare of individual animals. Even on an individual level, the relationship between reproductive effectiveness and animal welfare is complex. Good reproductive performance does not automatically signify good welfare, as domestication and targeted breeding programmes have led to prioritization of high productive and reproductive performance in most modern farm animal species. In this review, we synthesize literature regarding cattle husbandry, reproduction, welfare and their multidimensional relationships. We argue that practices such as artificial insemination or the use of sexed semen may provide potential welfare advantages as these practices reduce the risk of disease transmission and injury or enable selection of specific beneficial traits. Furthermore, they may offer a solution to current practices jeopardizing welfare, such as the management of surplus bull calves in the dairy industry. Conversely, the animals’ ability to perform natural behaviours such as oestrous expression, an aspect arguably contributing to welfare, is often limited on commercial farms; this limitation is particularly evident in housing systems such as tie stalls where movement is restricted. Moreover, common management practices such as oestrus manipulation may lead to negative attitudes in citizens who often regard naturalness as important element of animal welfare. 相似文献
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Small‐scale fisheries are recognised as making important contributions to nutrition and economic development despite a lack of accurate quantitative information on catches and consumption. While direct measurement remains the most appropriate way of collecting such data, it is impractical at large scales. Instead, household surveys based upon informant recall of fish caught and/or consumed are frequently used. However, the accuracy of weight recall by informants (even over short recall periods) has not been established. Using data from household surveys, the accuracy and precision of catch and consumption estimates derived from: (a) asking informants to recall weights of fish caught and (b) asking respondents to recall lengths of fish caught and converting to weight were tested. Length‐based methods, using visual aids to assist recall, were more accurate, precise and correctable. These methods could be useful for catch estimation, especially where fish are processed, sold or consumed shortly after capture. 相似文献
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Daniel Reed Stphane Plourde Adam Cook Pierre Pepin Benoit Casault Caroline Lehoux Catherine Johnson 《Fisheries Oceanography》2019,28(3):256-272
Commercially‐exploited fish populations are not only shaped by fishing pressure, but also by the dynamics of their environment. By quantifying the influence of environmental variability, fisheries management advice can be improved and uncertainties reduced. To this end, we developed statistical models of the response of Scotian Shelf silver hake stock metrics to variability in zooplankton community composition and phenology over the past 18 years and in the physical environment since 1985. Dominant modes of variability in these pelagic habitat indicators were characterized using principal component analysis, and the relationships of silver hake condition, abundance, and recruitment to pelagic habitat variability were assessed using generalized additive models. Condition was largely modulated by the onset and duration of the spring bloom, which controls food availability. In contrast, adult abundance was governed by composition of the zooplankton community and bottom‐water temperature, which dictates the distribution of silver hake. Finally, recruitment was affected by both thermal conditions and food availability. Our results presented here form the basis for qualitative assessment of ecosystem attributes and the influence on silver hake stock productivity. 相似文献
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Daniel C Dunn Caroline Jablonicky Guillermo O Crespo Douglas J McCauley David A Kroodsma Kristina Boerder Kristina M Gjerde Patrick N Halpin 《Fish and Fisheries》2018,19(4):729-739
Between 1950 and 1989, marine fisheries catch in the open‐ocean and deep‐sea beyond 200 nautical miles from shore increased by a factor of more than 10. While high seas catches have since plateaued, fishing effort continues to increase linearly. The combination of increasing effort and illegal, unreported and unregulated (IUU) fishing has led to overfishing of target stocks and declines in biodiversity. To improve management, there have been numerous calls to increase monitoring, control and surveillance (MCS). However, MCS has been unevenly implemented, undermining efforts to sustainably use high seas and straddling stocks and protect associated species and ecosystems. The United Nations General Assembly is currently negotiating a new international treaty for the conservation and sustainable use of biodiversity beyond national jurisdiction (BBNJ). The new treaty offers an excellent opportunity to address discrepancies in how MCS is applied across regional fisheries management organizations (RFMOs). This paper identifies ways that automatic identification system (AIS) data can inform MCS on the high seas and thereby enhance conservation and management of biodiversity beyond national jurisdictions. AIS data can be used to (i) identify gaps in governance to underpin the importance of a holistic scope for the new agreement; (ii) monitor area‐based management tools; and (iii) increase the capacity of countries and RFMOs to manage via the technology transfer. Any new BBNJ treaty should emphasize MCS and the role of electronic monitoring including the use of AIS data, as well as government–industry–civil society partnerships to ensure critically important technology transfer and capacity building. 相似文献