Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management

Managing fisheries resources to maintain healthy ecosystems is one of the main goals of the ecosystem approach to fisheries (EAF). While a number of international treaties call for the implementation of EAF, there are still gaps in the underlying methodology. One aspect that has received substantial scientific attention recently is fisheries‐induced evolution (FIE). Increasing evidence indicates that intensive fishing has the potential to exert strong directional selection on life‐history traits, behaviour, physiology, and morphology of exploited fish. Of particular concern is that reversing evolutionary responses to fishing can be much more difficult than reversing demographic or phenotypically plastic responses. Furthermore, like climate change, multiple agents cause FIE, with effects accumulating over time. Consequently, FIE may alter the utility derived from fish stocks, which in turn can modify the monetary value living aquatic resources provide to society. Quantifying and predicting the evolutionary effects of fishing is therefore important for both ecological and economic reasons. An important reason this is not happening is the lack of an appropriate assessment framework. We therefore describe the evolutionary impact assessment (EvoIA) as a structured approach for assessing the evolutionary consequences of fishing and evaluating the predicted evolutionary outcomes of alternative management options. EvoIA can contribute to EAF by clarifying how evolution may alter stock properties and ecological relations, support the precautionary approach to fisheries management by addressing a previously overlooked source of uncertainty and risk, and thus contribute to sustainable fisheries.     

The content of Hb and the hematocrit value in blood and the total proteins, urea, glucose, free fatty acids, Na, K, Ca, Mg, Pa, Fe, Fe-binding capacity, Cu and Zn in the blood plasma of Warmblood horses during feeding with oat-hay or barley-hay rations over a period of 9 months

4 horses (Group A) received an oat-hay ration, through 9 months running, while 3 horses (Group B) were fed a barley-hay ration over the same period of time. Blood samples were collected and examined in 4-week intervals. All values considered, no differences were found to exist between the 2 groups with regard to Hb and haematocrit in blood as well as to protein, glucose, sodium, potassium, magnesium, iron fixation capacity, copper, and zinc in blood plasma. The urea level in plasma of Group A was higher than that in Group B, values being 5.76 +/- 0.64 mmol/l and 5.14 +/- 0.72 mmol/l. The same applied to free fatty acids, values being 150 +/- 83 mumols/l in Group A and 95 +/- 42 mumols/l in Group B. Calcium was 3.10 +/- 0.27 mmol/l in Group A and 2.92 +/- 0.26 mmol/l in Group B, while the A-B difference in inorganic phosphorus amounted to 1.62 +/- 0.65 against 1.99 +/- 0.77 mmol/l. Group A was inferior to Group B also with regard to iron in plasma, values being 28.6 +/- 2.42 mumols/l against 32.8 +/- 4.62 mumol/l. Causes underlying these differences are discussed in some detail.     

Subatmospheric pressure storage of mango fruits

Ripening of mango fruit is markedly delayed when the pressure in the storage chamber is reduced below 100 mm Hg, and fruit storage life is thus prolonged. The prolongation of storage life is inversely related to the pressure; control fruit stored at 760 mm Hg started to ripen after 16 days in storage at 13°C, while fruit stored at 100 and 75 mm Hg after 25 and 35 days, respectively. Fruit stored at 50 mm Hg remained unripe for 35 days. No effect on ripening was recorded at pressures above 250 mm Hg, while at pressures below 50 mm Hg the fruit desiccated. All fruits stored at subatmospheric pressure ripened 3–4 days after transfer to shelf life at 25°C. However, green mango fruits of the colored cultivars like ‘Haden’ and ‘Maya’, stored at subatmospheric pressure for a prolonged period, did not develop the proper red or orange color during shelf-life, but turned pale yellow instead. Treatment with ethylene upon removal from storage slightly improved color development in these fruits.     

Eating and ruminating behavior of sheep. 2. Experiments in pregnant and lactating ewes fed with a straw-concentrate mixture

Fertility oriented ewes in the late stage of gestation and during the lactation period received 19 feeding regimes on the basis of straw-concentrate mixtures, which essentially differed in the feedstuff structure. The ewes fed ad libitum on average used between 5 and 6 hours per day feed intake in the 86 measuring periods. The average daily ruminating time ranged from 398 to 502 minutes. An increasing straw content resulted in significantly longer ruminating periods and a higher number of masticatory movements, additional quotas of long straw had non effect. But even the most unfavourable feeding variants (straw-concentrate mixtures with 40% straw meal treated with NaOH) elicited 21 100 ruminating masticatory movements in 5 hours of ruminating. There were no significant differences between the absolute consumption and ruminating activities in the late stage of gestation and the lactation period; with reference to feed and crude fibre intake the ruminating expenditure in the late stage of gestation was always significantly higher. Rations with a low structural effect resulted in a more unbalanced distribution of consumption and ruminating activities in the course of the day than well structured rations.     

Changes in amylase activity,starch and sugars contents in mango fruit pulp

Amylase activity in developing mango fruits increased parallel to the increase in fruit weight. During ripening there was a decrease in starch content and an increase in the reducing and non-reducing sugars. The enzyme preparation which was extracted from acetone powders of mango fruit was inhibited by inhibitors of both α- and β-amylases, and mercapto-ethanol reversed the inhibition by p-hydroxymercuribenzoate. Polyacrylamide gel electrophoresis of the solubilized enzyme has shown only one main band of amylase activity and has indicated the presence of a proteinaceous amylase inhibitor in the fruit pulp. Changes taking place during development and ripening, as well as the nature of the amylolytic activity in mango fruits, are discussed.     

A comparison of florfenicol and tulathromycine for the treatment of undifferentiated fever in feedlot calves

The purpose of this study was to compare the relative cost-effectiveness of florfenicol with that of tulathromycin for treatment of undifferentiated fever (UF) in feedlot calves at ultra-high risk of developing UF that receive metaphylactic tulathromycin on arrival at the feedlot. Calves that received therapeutic florfenicol had lower overall mortality (P=.045) and bovine respiratory disease mortality (P=.050) compared with calves that received therapeutic tulathromycin, but no significant differences were detected in feedlot performance, carcass characteristics, or other animal health variables. There was a net advantage of Can$41.19/treated animal in the florfenicol group versus the tulathromycin group. This study demonstrates that it is more cost-effective to use florfenicol than tulathromycin for the initial treatment of UF in feedlot calves at ultra-high risk of developing UF that receive on-arrival metaphylactic tulathromycin.