The Ecology of Patella From the Cape Peninsula South Africa

Forty-six species were recorded in association with Patella spp., but most of these are casual associates, seeking temporary shelter. The shell surface offers an important substrate for algae.

The amphipod Hyale grandicornis is often associated with Patella, particularly in the juvenile stages. It is a facultative inquiline which vacates its hosts at high tide. The isopods Dynamenella australis and D. scabricula are predominantly associated with limpets and complete their life cycles under limpets. Choice chamber experiments demonstrate their preference for sheltering under limpets. The copepod Scutellidium patellarum is similar, but the association is more marked.

Calliopiella michaelseni (Amphipoda) is commensal and show a preference for certain limpet species. Its colour changes in relation to the host species. Feeding occurs on limpet faeces and algal fragments. The life cycle is completed under the limpet, two reproductive peaks occurring each year. Adults usually occur in pairs and there is a positive correlation between host and amphipod size. Juveniles remain with their parents initially, and then disperse to other limpets. Adult pairs may defend their host, excluding other amphipods. Calliopiella is strongly photonegative and thigmotactic.

The turbellarian Notoplanapatellarum is preferentially commensal with Patella oculus. This can be experimentally demonstrated. It feeds on small Crustacea, including Scutellidium.     

Feeding ecology of major carnivorous fish from four eastern Cape estuaries

Stomach content analyses were performed on eight carnivorous fish from four eastern Cape estuaries. Dietary importance was assessed by using three unrelated methods and by combining them to determine the index of relative importance of each food item. It was attempted to relate the percentage of fish with food in the stomach and the feeding intensity to the abundance of the fish in a particular estuary. In general fish consumed more food in estuaries where they were more abundant. The few exceptions that occurred could indicate that a particular estuary was selected for purposes other than food availability eg. Tachysurus feliceps in the Krom estuary for spawning grounds or because of inter- or intraspecific competition for food eg. T. feliceps and Monodactylus falciform is in the Krom and Argyrosomus hololepidotus in the Gamtoos and Sundays estuaries. Similarity analyses showed resource partitioning. Predators such as A. hololepidotus, Elops machnata, Lichia amia and Platycephalus indicus preferred teleost fishes such as mullets and Gilchristella aestuarius, whereas the stomach content of Pomadasys commersonnl, T. feliceps and M. falciform is were dominated by Crustacea, particularly Upogebia africana. Most estuarine predators showed a diverse prey selection, but the food web was characterized by a high energy flow per pathway.     

The effect of diets supplemented with fish broth and fish oil on the health of weaners

The aim of this study was to determine the effect of fish-based feed materials, as a source of readily available protein contained in fish broth and essential polyunsaturated fatty acids (PUFAs) found in fish oil, on the health of piglets and rearing results. The experiment was conducted on a commercial pig fattening farm. The study involved a total of 80 weaners with an approximate body weight of 15 kg. The experiment was carried out over a period of 40 days. Feed samples were subjected to laboratory analyses. Blood samples were collected from experimental group animals to determine serum biochemical and immunological parameters. The body weight gains of weaners, mortality rates and average feed intake per animal were calculated for the entire experimental period. The addition of fish broth and fish oil significantly improved the n3:n6 fatty acid ratio in diets. The presence of EPA and DHA in the experimental diet could have had a positive health effect on piglets, comparable with that exerted by therapeutic doses of zinc often administered to pigs of this age group. During the experiment, feed conversion ratio (FCR) gain was considerably reduced in the experimental group, with similar daily gains in the control and experimental group.     

Aspects of Population Structure of Parechinus Angulosus Leske,Around the Cape Peninsula

Aspects of the community structure of Parechinus angulosus, a locally dominant echinoid, were studied in two inshore temperature environments on the Cape Peninsula for a year. Stratified, random transects of 10 stations were run seasonally across the aireas of maximum density at each locality and urchins were counted, measured and sexed. Percentage substrate cover was calculated, and variation in urchin size with distance from shore was investigated. Individual and combined effects of locality, season, distance (and depth) and sex were tested. Results indicate that urchins found at the cold- water locality, were on the average smaller, more numerous and included more size classes than the other. Urchin density did not vary with distance from shore at either locality, but was dependent on kelp, the occurrence of which is controlled by the nature of the substrate and by light penetration. A test of sex ratios was significant, males being more numerous. No seasonal effect on urchin distribution could be shown. There was no interaction of factors, except a small one between locality and season.     

The effects of river flooding on the fish populations of two eastern Cape Estuaries

The effect of river flooding during July and August 1979 on fish populations in two eastern Cape estuaries is compared. It is shown that floods of varying intensity occur regularly in these estuaries. Fish populations in the two estuaries, namely the Swartkops and the Sundays, were differently affected: members of the family Mugilidae increased in numbers in the Swartkops estuary after the floods but decreased to insignificant numbers in catches in the Sundays estuary for a number of months after the floods. It is postulated that mud and silt which are deposited in the Swartkops during the flood serve as a food source for the mullet whereas the rich surface benthos layer of a channel-like estuary like the Sundays is washed away by heavy floods.     

First record of freshwater fish on the Cape Verdean archipelago

The Cape Verdean islands form a distinct aquatic freshwater ecoregion characterized mainly by temporal water bodies with an adapted invertebrate community. Freshwater fish were not previously recorded from the archipelago. During a non-exhaustive survey of freshwater bodies on five islands of the archipelago, the first presence of a freshwater fish was recorded. Using barcoding sequences, the species was identified as the guppy (Poecilia reticulata), a highly invasive species alien to the Cape Verdean Islands.     

Faecal analysis suggests generalist diets in three species of Western Cape cordylids

Climate has been proposed as an explanation for the present-day distribution of closely-related melanistic and non-melanistic cordylid species in the southwestern Cape of South Africa. However, diet may also contribute towards shaping geographic distributions. We present preliminary data on diet composition based on analyses of faecal pellets of Cordylus cordylus (non-melanistic), C. niger (melanistic) and C. oelofseni (melanistic). Coleoptera were the most common prey ingested both in summer and early spring for all species, followed by Hymenoptera for all species in summer. The overlap in other arthropod taxa ingested was low across species and seasons, suggesting an opportunistic component to their foraging behaviour.We distinguished plant matter in faecal samples of all species in all seasons, reflecting either voluntary or accidental ingestion. The results of this study suggest that the generalist diets of these cordylid species should not constrain their distributions despite the common preference for coleopterans.     

A correction factor for,and its application to,visual censuses of littoral fish

Visual estimation techniques were used between October 1976 and May 1977 on the fish fauna of an enclosed mid-intertidal pool in the eastern Cape, South Africa, to test the usefulness and accuracy of this non-consumptive census method. In January, 1977, two pools were censused for fish, then poisoned using the ichthyocide ‘pronoxfish’ and all fish collected. Forty species in 21 families were obtained from the two stations. The accuracy of visual estimates varied with the species of fish. Secretive and cryptically coloured types, as well as species which Inhabit crevices, were underestimated, between 0 and 86% being counted. Other fish with protective colours but that occur more openly and do not react adversely to divers, as well as schooling species, were also underestimated, but up to 100% of the total were observed. Those which occur singly or in small groups in the water column were counted more accurately, with 57 to 100% of the actual number being seen. Correction factors were calculated from these data and applied to a census taken of one pool in May. Comparisons of corrected and actual numbers Indicate that these factors were relatively accurate for non-secretive species. The factors will, however, vary for each species, from observer to observer, depending on their personal experience, and from area to area.     

Effect of select menhaden fish meal in starter diets for pigs

Two trials were conducted to evaluate a select menhaden fish meal (SMFM) as a protein source in starter diets for 390, 3-wk-old weaned pigs. Initial weights averaged 4.8 and 5.5 kg in Trials 1 and 2, and trials were conducted for 5 and 4 wk, respectively. Diets in Trial 1 were formulated by substituting levels of 0, 4, 8, 12, 16 or 20% SMFM for soybean meal plus corn on a protein basis. The 20% fish meal diet contained no soybean meal; all diets contained between 19.8 and 20.2% CP, between 1.34 and 1.40% lysine and 25% dried whey. Replacement of soy protein with fish meal elicited a quadratic improvement (P = .01) in cumulative ADG and average daily feed intake (ADFI) by the end of wk 5. The diet containing 8% SMFM resulted in the maximum observed ADG; however, the maximum ADFI occurred in pigs fed the diet containing 12% SMFM. Breakpoint analysis indicated that 4.5 and 9.3% SMFM maximized ADG and ADFI, respectively. Addition of SMFM did not affect efficiency of feed utilization (F/G). In Trial 2, a 2 X 3 factorial with two levels of dried whey (10 or 20%) and three levels of SMFM (0, 4 or 8%), a SMFM X dried whey interaction (P less than .05) was observed for cumulative ADG and F/G by the of wk 4 with greater benefit from SMFM with 10% than with 20% dried whey.(ABSTRACT TRUNCATED AT 250 WORDS)     

翘嘴鳜苗当年养成商品鱼试验

翘嘴鳜是鳜鱼中生长速度最快的品种,为了缩短养殖周期,降低生产成本,提高经济效益,笔者于2005年在沅江市黄茅洲镇金南渔场主持了翘嘴鳜苗池塘当年养成商品鱼的试验,现将试验情况综述如下。1材料与方法1.1池塘条件翘嘴鳜养殖试验池1口,面积3335m2,水深2m,池底平坦,淤泥少;饵料鱼     

水果蔬菜和鱼类的副产物作为猪饲料的可行性分析

我们对水果蔬菜和鱼类的副产物作为育肥猪的饲料进行了可行性分析。这些副产物主要是指水果蔬菜的皮、核以及鱼内脏等，主要来自于西班牙的Salamanca的商店，并且对它们的营养成分、矿物质含量以及可消化性进行了评估。在本次实验中，这些副产品的干物质含量偏低（在果菜和鱼类副产物分别为12％和26％），但这些干物质却包含了所有猪饮食中所需的营养成分。鱼类的副产物含有58％的粗蛋白、22％的灰份、19％的醚提取物和1％的粗纤维，而果菜副产物中含有65％自由氦提取物、13％粗纤维、12％粗蛋白、8％的灰份以及2％醚提取物。这些副产物随着温度的升高，它们的可消化性会逐渐降低，所以温度高于65℃的果菜副产物和高于105℃的鱼类副产物，我们都予以废弃，这也是出于控制微生物含量的考虑。     

从日粮中获得更多的能量

猪的内源性酶可以帮助其从传统的玉米-豆粕型生长-育肥期日粮中获取大部分能量。然而,研究表明,日粮中添加新型复合酶制剂能使日粮能量被更多地用于生长,因而可提高饲料的利用效率。     

利用鱼糜加工废弃物制备饲用鱼油的研究

为有效利用鱼糜加工废弃物,试验以过氧化值为指标,研究了以鱼糜加工废弃物制备鱼油的工艺条件,探讨了鱼油的提取(时间、温度、pH等)及精制工段对鱼油品质的影响,并对异维生素C钠、植酸钠、2,6-二叔丁基对甲酚(BHT)、特丁基对苯二酚(TBHQ)等抗氧化剂对鱼油的抗氧化效果进行分析。结果表明,鱼油适宜提取条件为温度85℃、pH为9.0、时间40 min,抗氧化剂以TBHQ效果最佳。     

Paratuberculosis in European wild rabbits from the Iberian Peninsula

Of the non-ruminant wildlife species known to harbor Mycobacterium avium paratuberculosis (MAP), the rabbit (Oryctolagus cuniculus) is thought to pose the greatest risk of transmission to cattle. We analyzed 80 hunter-harvested wild rabbits from a core study area in southern Spain, and sera from 157 wild rabbits sampled opportunistically on seven additional sites. Gross lesions compatible with paratuberculosis were observed in two of 80 necropsied rabbits. Histopathology revealed focal to diffuse multibacillary MAP-compatible lesions in 8 of 10 rabbits examined. Presence of MAP was confirmed in one rabbit with gross lesions by positive amplification curves for both IS900 and ISMAP02. However, no isolate was obtained from 47 samples by culture. We adapted an indirect ELISA for the detection of MAP antibodies. At the established cut-off of 0.5, 6 of 237 wild rabbit sera (2.5%) yielded a positive ELISA result. Antibodies were detected in rabbits from 3 of 8 sampling sites. Considering the increasing relevance of MAP infection for animal health, these results open a challenging field for future research.     

The effect of supplementing organic diets with fish meal and premix on the performance of pigs and some meat and blood characteristics

The aim of this study was to determine the effect of fish meal and mineral-vitamin premix, supplementing organic diets, on the performance of pigs and some meat and blood characteristics. The experiment was conducted on an organic pig fattening farm. The study involved 120 pigs with an approximate 25 kg body weight. Animals were divided into 3 groups, kept in pens, 10 animals each. Group I (control) animals were fed with plant feedstuffs of organic origin. Diets for group II and III were enriched with fish meal or fish meal and vitamin-mineral premix, respectively. The experiment was carried out till pigs reached a weight of 115 kg. Feed samples were subjected to laboratory analyses. Body weight (3 times) and feed intake were recorded. Blood samples were collected (2 times) to determine hematological and biochemical indices. Some parameters in meat samples were also determined. The fish meal addition improved (P < or = 0.05) the average daily gains as well as feed conversion ratio during fattening period and mineral-vitamin premix significantly (P < or = 0.05) fortified fish meal influence. Fish meal supplement improved (P < or = 0.05) also some carcass characteristics. Supplementation of the diet with premix additionally decreased (P < or = 0.05) backfat thickness and increased share of meat in carcass. Fish meal improved (P < or = 0.05) some meat characteristics and elevated content of some polyunsaturated fatty acids. An increase in hemoglobin, red blood cell, white blood cell and cholesterol level in blood of animals from both experimental groups were also found. The results obtained proved the usefulness of fish meal and mineral-vitamin premix in the fatteners nutrition based on organic diets.     

金鲳鱼饲料中发酵豆粕替代鱼粉的研究

试验采用单因子试验设计,选用初始体重为(60±4)g的金鲳鱼(Trachinotus ovatus),随机分成5个处理,每个处理3个重复,每个重复20尾鱼,饲养在浮式海水网箱中,进行为期65 d的试验。在对照组配方中鱼粉用量为51%的基础上,分别用13%、24%、34%和44%的发酵豆粕代替配方中9%、16%、23%和31%的鱼粉用量,研究发酵豆粕代替鱼粉对金鲳鱼生长性能的影响。试验结果表明:在金鲳鱼饲料中用发酵豆粕代替23%的进口鱼粉,金鲳鱼的增重率、特定生长率、饲料系数与对照组无显著性差异(P>0.05)。在本试验条件下,发酵豆粕代替25%的鱼粉用量对金鲳鱼的生产性能不会产生不良影响。     

Studies on the littoral seaweed epifauna of St Croix Island I Physical and biological features of the littoral zone

The physical and biological features of the littoral zone of St. Croix Island are described as a prelude to studies on the seaweed epifauna. Wave action is the most important physical variable and shore community structure is markedly influenced by the differing degrees of wave action around the Island. Sheltered, moderately exposed, exposed and very exposed littoral communities are distinguished and at three transects the zonation of the macrofauna and the percentage cover of the littoral seaweeds is determined. Seasonal variation, particularly in the seaweed Porphyra capensis, is documented, seaweed cover is related to biomass and energy values for 14 littoral seaweeds are determined.     

Sow litter size is increased in the subsequent parity when lactating sows are fed diets containing n-3 fatty acids from fish oil

Supplementing diets with n-3 fatty acids from fish oil has been shown to improve reproductive performance in dairy cattle and sheep, but there is little published literature on its effects in sows. The aim of this study was to evaluate the reproductive performance of sows fed fish oil as a source of n-3 PUFA prefarrowing and during lactation. From d 107.7 ± 0.1 of pregnancy, 328 sows ranging in parity from 0 to 7 (parity 1.95 ± 0.09, mean ± SE) were fed either a diet containing tallow (control) or an isocaloric diet containing 3 g of fish oil/kg of diet (n-3). Diets were formulated to contain the same amount of DE (13.9 MJ/kg), crude fat (54 g/kg), and CP (174 g/kg). Sows were fed their treatment diet at 3 kg daily for 8 d before farrowing and continued on treatment diets ad libitum until weaning at 18.7 ± 0.1 d of lactation. After weaning, all sows were fed a gestation diet without fish oil until their subsequent farrowing. There was no effect (P > 0.310) of feeding n-3 diets prefarrowing on piglet birth weight, preweaning growth rate, piglet weaning weight, or sow feed intake. However, n-3 sows had a larger subsequent litter size (10.7 ± 0.3 vs. 9.7 ± 0.3 total born; 10.2 ± 0.3 vs. 9.3 ± 0.3 born live; P < 0.05). In conclusion, this is the first study to demonstrate that feeding sows a diet containing n-3 PUFA from fish oil fed before farrowing and during lactation increased litter size in the subsequent parity independent of energy intake.