Spatio‐temporal management of fisheries to reduce by‐catch and increase fishing selectivity

Time/area closures have been widely used in fisheries management to prevent overfishing and the destruction of marine biodiversity. To a lesser degree, such spatio‐temporal management measures have been used to reduce by‐catch of finfish or protected species. However, as ecosystem‐based management approaches are employed and more fisheries are managed through multispecies, multiobjective models, the management of by‐catch will likely become increasingly important. The elimination of by‐catch has become a primary goal of the fishing policies of many countries. It is particularly relevant in the United States, as the deadline for setting annual catch limits (ACLs) in all fisheries passes in 2011. This will result in a dramatic expansion of the number of catch and by‐catch quotas. Such catch measures may result in the early closure of otherwise sustainable fisheries when by‐catch quotas are exceeded. To prevent such closures and the consequent economic hardship to fishers and the economy, it is imperative that managers be given the tools necessary to reduce by‐catch and improve fishing selectivity. Targeted spatio‐temporal fishery closures are one solution open to managers. Here, we examine how the spatio‐temporal and oceanographic characteristics of by‐catch may be used by managers to design fishery closures, and place these methods within a decision tree to assist managers to identify appropriate management measures. We argue that the current movement towards marine spatial planning (MSP) presents an important impetus to examine how we manage fisheries spatially, and we offer a first step towards the objective participation of fisheries in the MSP process.     

Simultaneous histochemical determination of three fiber types in single sections of ovine, bovine and porcine skeletal muscle

Classification of muscle fiber types involves tedious comparisons of serial muscle tissue sections. Procedures that would incorporate pertinent histochemical properties into one simplified assay for the successful differentiation and determination of fiber types were evaluated using muscle samples from three different species (ovine, bovine and porcine). For ovine and porcine muscle tissue, the best staining procedure involved initial preincubation of the tissue section at 4.35 (for ovine) and 4.30 (for porcine) followed by incubating for succinate dehydrogenase (SDH) activity, then staining for myofibrillar adenosine triphosphatase (ATPase) activity after an acid preincubation and, finally, counterstaining with hematoxylin. For bovine muscle tissue, the procedure involves first incubating for SDH activity, after which the section is incubated at pH 4.15 and then stained for myofibrillar ATPase activity after an acid preincubation, with a concluding counterstaining using hematoxylin. These procedures permit successful differentiation and identification of three fiber types (beta R, alpha R and alpha W) from a single section of muscle tissue with approximately a 65% saving in time and materials. The results of histochemically typing muscle fibers in a single tissue section stained with these techniques were similar to those obtained with the traditional methods comparing serial sections.     

Effects of nutrient deficiencies and excesses on reproductive efficiency of livestock.

Successful reproduction is dependent on a host of macro- and micronutrients and ceases well before an animal expires from deficiency of a particular nutrient. This review focuses on the functional roles phosphorus, vitamin A and beta-carotene, protein, and energy play in reproductive processes. Although it is not known whether deficiencies of these nutrients limit reproduction through common or discrete mechanisms, appropriate quantities of these nutrients are required for optimal reproduction. Mechanisms through which nutritional status is perceived by the hypothalamic-pituitary-gonadal axis remain unclear but seem to impinge on hypothalamic regions that selectively regulate production and release of pituitary trophic hormones. Body condition, or degree of fatness, seems to be the most reliable indicator of well-being of an animal, and, when coupled with changes in BW, provides a useful method to assess reproductive potential.     

Failure to detect luteinizing hormone-releasing hormone-like bioactivity in fluid of preovulatory ovine follicles

To determine if a luteinizing hormone-releasing hormone (LH-RH)-like substance accumulates in fluid of follicles destined to ovulate, we obtained the fluid component of preovulatory ovine follicles at various times before, during, and after the endogenous surge in pituitary secretion of LH. The fraction of follicular fluid suspected of containing LH-RH was isolated by reverse-phase column chromatography. Luteinizing hormone releasing activity of the preparation was ascertained using an anterior pituitary cell bioassay of high sensitivity. In no instance was activity of a peptide similar to LH-RH revealed in fluid obtained from preovulatory follicles of ewes.     

Disseminated Osteomyelitis Caused by Clostridium novyi in a Cat

The history, clinical signs, laboratory and radiological findings of a cat with polyostotic osteomyelitis are described. A disseminated periosteal reaction involving the femur, humerus and tibia bilaterally was evident on radiographs. The joints were not affected. Diagnosis of osteomyelitis was confirmed by bone marrow aspiration and bone biopsy. Clostridium novyi was cultured from the bone marrow.     

Diagnostic investigations in 101 dogs with pyrexia of unknown origin

Records from 101 dogs presented for investigation of unexplained pyrexia were reviewed. The most common diagnosis was immune-mediated disease (22 per cent of cases), with immune-mediated polyarthritis accounting for 20 per cent of all diagnoses. The frequency of positive results obtained in investigative tests was also assessed. Cytological and radiological examinations provided a high diagnostic success rate, although routine haematology and plasma biochemistry were also useful screening tests. On the basis of these results it is suggested that, in the investigation of unexplained pyrexia, a diagnosis of immune-mediated polyarthritis should be excluded before less common diagnoses are considered.