Distribution by Scientific Domains

Kinds of Catch

  • allowable catch
  • commercial catch
  • fish catch
  • incidental catch
  • light trap catch
  • moth catch
  • total allowable catch
  • total catch
  • trap catch

  • Terms modified by Catch

  • catch data
  • catch rate

  • Selected Abstracts


    ABSTRACT Histamine formation in Sardina pilchardus and Engraulis encrasicolus as a function of storage temperature was studied. Fish were caught off the Adriatic Coast and were carried immediately to the laboratory. A portion of dorsal muscle from each fish was soon analyzed, while two other portions were examined after storage at two different temperatures (25 and 4C) for 24 and 72 h, respectively. The analyses were carried out by high-performance liquid chromatography (HPLC)-UV and confirmed by HPLC-diode array detector. Histamine concentrations were always higher than the European Community admissible levels in samples stored at 25C. In fish stored at 4C, histamine was detected only in E. encrasicolus. PRACTICAL APPLICATIONS Time experiments were conducted to quantify the histamine formation in scombroid species at two different temperatures. The first assay (24 h, 25C) could reproduce the modality of sale adopted by fishermen or retailers in summer on the one hand, and the maintenance at ambient temperature of semipreserved sardines or anchovies during salting and ripening on the other hand. The second experiment (72 h, 4C) was based on the domestic cold preservation of fish before the consumption, which sometimes occurs some days after purchasing. Even if ice storage is recommended, time/temperature abuse conditions often occur in the fish merchandising chain. The results of this research showed that high histamine concentrations could be found in the analyzed species not only at an abused temperature, but also at a common storage temperature of fish at home. [source]

    Craniofacial cephalometric morphology in children with CATCH 22 syndrome

    A Heliövaara
    Structured abstract Authors ,, Heliövaara A, Hurmerinta K Objectives ,, To evaluate cephalometrically the craniofacial, pharyngeal and cervical morphology in children with CATCH 22, and to compare and quantify the findings with age- and sex-matched controls. Design ,, A retrospective case,control study. Setting and Sample Population , Forty-one children (20 girls) with CATCH 22 were compared with age- and sex-matched controls from lateral cephalograms taken at the mean age of 8.5 years (range 5.8,12.9). The deletion of 22q11 was verified by fluorescence in situ hybridization techniques. Thirteen of the children with CATCH 22 had palatal clefts. Outcome measure ,, Linear and angular measurements were obtained from lateral cephalograms. A Student's t -test and a paired Student's t -test were used in the statistical analysis. Standard deviation scores (SDS) were calculated to quantify the variation. Results ,, Children with CATCH 22 had obtuse cranial base angles and long anterior cranial bases. Their faces were long with increased facial convexity. The maxillae were long but both jaws were retrognathic and the lower jaws posteriorly diverged. The pharynges were wide in the nasopharyngeal area and narrow in the hypopharyngeal area. The development of the hyoid bones was delayed, and hyoid bone and atlas lengths were reduced. The morphology of the children with CATCH 22 with and without a palatal cleft was similar. Despite several statistically significant differences between the children with CATCH 22 and the controls, the SDS did not exceed ±2 for any of the measurements. Conclusion ,, Children with CATCH 22 have several minor distinctive morphological features in the craniofacial, pharyngeal, and cervical areas. [source]

    Habitat use of age 0 Alabama shad in the Pascagoula River drainage, USA

    P. F. Mickle
    Mickle PF, Schaefer JF, Adams SB, Kreiser BR. Habitat use of age 0 Alabama shad in the Pascagoula River drainage, USA. Ecology of Freshwater Fish 2010: 19: 107,115. © 2009 John Wiley & Sons A/S Abstract,, Alabama shad (Alosa alabamae) is an anadromous species that spawns in Gulf of Mexico drainages and is a NOAA Fisheries Species of Concern. Habitat degradation and barriers to migration are considered contributing factors to range contraction that has left just the Pascagoula River drainage population in Mississippi. We studied juvenile life history and autecology in three rivers within the drainage. We collected fish, habitat and physicochemical data in three habitat types (sandbar, open channel and bank) from June to October 2004,2006. Sandbar habitat was favoured by smaller individuals early in the year. Catch per unit effort (CPUE) decreased through the summer as larger fish began occupying bank and open channel habitat. The most parsimonious model of abundance included year and river variables, while patterns of presence and absence were best explained by river, habitat type and physiochemical variables. While all three rivers in the drainage contained Alabama shad, fish were less abundant and had lower condition values in the Chickasawhay River. Earlier work suggested the Alabama shad may gradually move downstream towards the Gulf of Mexico in their first year. However, we found no evidence of this and captured large fish high in the drainage late in the year. [source]

    Characteristics and economic contribution of a developing recreational fishery in southern Angola

    W. M. POTTS
    Abstract, The characteristics and contribution of a developing recreational fishery to the local, regional and national economy of Angola were evaluated in 2006. Annual angling effort was 13 435 h, while the estimated total catch of the three target species [leerfish, Lichia amia (L.), west coast dusky kob, Argyrosomus coronus (Griffiths & Heemstra) and shad, Pomatomus saltatrix (L.)], was 5913 fish with a mass of 27 975 kg. Catch per unit effort (CPUE) for all teleost species combined was 0.44 fish per angler h,1 and 2.08 kg per angler h,1. Total harvest of the three species was 576 fish with a total mass of 2221.6 kg. The total contribution of this recreational fishery (mostly anglers from South Africa) to the local economy was US$ 1007 per harvested fish and US$ 243 per harvested kg. This equated to a contribution to the local, regional and national economies of US$ 151 685, US$ 44 767 and US$ 344 364 respectively. Although the regional contribution was less than half of the national contribution, it was regionally significant when the low population density and the general absence of other formal sector employment opportunities are considered. As a result of the largely undisturbed nature of the southern Angolan coastline, the catch, effort and CPUE information was considered suitable as a baseline for a cost-effective method of future fisheries monitoring in the region. [source]

    Factors influencing fish catch levels on Kenya's coral reefs

    S. C. Mangi
    Abstract, The factors influencing fish catches on Kenya's coral reefs were studied. Catch data were collected at the species level by counting the number of fish landed at each landing site of each fishing ground. Live coral cover, topographic complexity, fish and sea urchin density, and the number of fishers and gear units used in each fishing ground were compared with catch data. Fishing grounds included one location where only basket traps were allowed, six locations where all gear types were used except beach seines, and three locations where all types of gear, including beach seines, were used. Catch and effort variables were similar across the fishing grounds whereas live coral cover and sea urchin density differed (P < 0.01). The sites fished by all types of gear including beach seines had the lowest coral cover (8.4 ± 0.9%) and topographic complexity (1.12 ± 0.01). Catch levels were positively correlated with the number of fishers and fish density but not with the number of gear units deployed or sea urchin density. The number of fishers and live coral cover were the strongest factors determining total catch levels. The results suggest that high levels of fishing effort coupled with the use of destructive gear types, exacerbate the effects of overfishing on Kenya's reefs. [source]

    Sediment preferences and size-specific distribution of young-of-the-year Pacific halibut in an Alaska nursery

    A. W. Stoner
    A combination of laboratory experiments and field surveys was used to test the hypotheses that responses to sediments change with fish size and that sediment grain-size is the predominant environmental factor affecting small-scale distribution in young-of-the-year (yoy) Pacific halibut Hippoglossus stenolepis. Laboratory tests showed that the smallest fish (31,40 mm LT) chose fine sediments (muddy and fine sands), fish 51,70 mm had high selectivity (primarily medium sand), and the largest fish (80,150 mm) were not selective although they avoided the largest grain-sizes (pebbles and granules). Sediment preferences were correlated with size-dependent burial capabilities. Beam trawl collections were made over a 6 year period in Kachemak Bay, Alaska, to examine the distribution of yoy Pacific halibut (14,120 mm LT) using small size classes (e.g. 10 mm intervals). Canonical correlation analysis showed that the per cent of sand in the sediment was a highly significant variable for all but one size and date combination. Catch per unit of effort (CPUE) for newly settled fish (<30 mm LT) was highest on very fine sand, fish 41,80 mm were most abundant on fine sand, and the largest yoy fish (81,120 mm) were abundant over a range of sediments from fine sand to mud. Except for the smallest fish, Pacific halibut in the field were associated with sediments somewhat finer than predicted from the laboratory experiments; however, virtually all were captured where they could bury easily. The ability of flatfish to bury and shelter in sediment is related to fish size; consequently, habitat associations shift rapidly during the first year of life. Habitat models for yoy flatfishes should consider size-dependent shifts in capabilities and preferences. [source]

    Developing best practice in critical care nursing: knowledge, evidence and practice

    Paul Fulbrook
    Summary ,Because the current drive towards evidence-based critical care nursing practice is based firmly within the positivist paradigm, experimentally derived research tends to be regarded as ,high level' evidence, whereas other forms of evidence, for example qualitative research or personal knowing, carry less weight ,This poses something of a problem for nursing, as the type of knowledge nurses use most in their practice is often at the so-called ,soft' end of science. Thus, the ,Catch 22' situation is that the evidence base for nursing practice is considered to be weak ,Furthermore, it is argued in this paper that there are several forms of nursing knowledge, which critical care nurses employ, that are difficult to articulate ,The way forward requires a pragmatic approach to evidence, in which all forms of knowledge are considered equal in abstract but are assigned value according to the context of a particular situation ,It is proposed that this can be achieved by adopting an approach to nursing in which practice development is the driving force for change [source]

    Selective Catch and Release of a Synthetically Useful Phosphine Ligand.

    CHEMINFORM, Issue 1 2004
    Jennifer L. Marugg
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Present status, and social and economic significance of inland fisheries in Germany

    H. Wedekind
    The Federal Republic of Germany is situated in the central part of Europe and covers an area of 358 000 km2. The climate is maritime in the north and continental in the south with precipitation varying between 600 and 2000 mm year,1. Lakes and farm ponds are common in the north-eastern part of the country and in the alpine and pre-alpine regions to the south. A great number of small natural and artificial water bodies exist all over the country. There are about 800 000 ha of inland waters. The population of 82 million people are concentrated around a number of large conurbations. Over the last 150 years, intense use of the water resources by industry led to pollution and a severe decrease in river and lake fisheries. Only 587 inland fishing enterprises still existed in the early 1990s. Catches from commercial fisheries are decreasing with a total of 3469 t being caught in 1998. The Lake Constance fishery, which landed about 840 t in 1998, is an exception to the general trend. Strong competition for the aquatic resource is affecting commercial fisheries, whilst recreational fisheries have gained increasing importance over the last decades. Recent studies provided basic information on anglers' habits, social structure and economic significance as well as their effects on the waters. Aquaculture mainly produces rainbow trout, Oncoryhnchus mykiss (Walbaum) 20 000 t and carps (12 000 t) e.g. Cyprinus carpio L. Despite pressures from industry and conservation movements, regional support for fisheries and their development has intensified, leading to improved water quality. There are even attempts to re-establish abandoned fisheries. Co-operation with conservationists provides an opportunity for the future survival and development of fisheries. The fisheries and aquaculture sectors changed drastically after the reunification of Germany. The collapse of the infrastructure in the eastern part of Germany led to a decline in production and to a special investigation on recent developments of this sector. [source]

    Survey augmentation using commercial vessels in the Mid-Atlantic Bight: Sampling density and relative catchability

    E. N. Powell
    Summary A series of side-by-side tows was conducted between a survey vessel and a commercial vessel in two seasons, spring and fall (autumn), to examine the use of commercial vessels to increase sampling density in trawl-based stock surveys. Both vessels caught more fish offshore in the spring. The commercial vessel caught more fish than the survey vessel in both seasons. Catches of nearly all species were contagiously distributed in the spring. Most were contagiously distributed in the fall; however, somewhat more species were characterized by random or even distributions. The variance-to-mean ratio was consistently higher for most species for commercial vessel catches, regardless of season. As both vessels sampled in the same region at the same time, the increased predilection for the survey vessel to assess the distribution pattern as less patchy than the commercial vessel must accrue from some difference in sampling dynamics rather than variation in species distribution. A simulated decrease in sampling effort from 59 to 30 or 15 hauls increased the variance-to-mean ratio. Reduced sampling effort increased the tendency for occasional large catches to vary the estimate of domain biomass. The sampling program included an onshore,offshore gradient in station density. Domain biomass was considerably underestimated with reduced station density for six species characterized by large catches offshore in that portion of the survey domain characterized by low station density. In this study, a factor of two variation in domain biomass became more likely in 40% of species when sampling effort was reduced to 15 hauls from 59. A factor of two in biomass may distinguish a sustainable fishery from one in which a species is overfished. As survey sampling effort in this area was 18 hauls, increasing sample number by inclusion of commercial vessel tows would be advantageous. A regression between paired tows failed to adequately predict catches of one vessel from catches of the other. Standardization of vessel catches by the ratio-of-mean catches provided a more realistic comparison because large catches accounted for a significant fraction of domain biomass; however, a single conversion coefficient between boats could not be used for both sampling periods. The underlying impediment in developing a general conversion factor between the two vessels seems to be rooted in the differential in variance-to-mean ratios of the catches; this differential exists despite sampling of the same distribution of fish. [source]

    Abundance and distribution of fish in the lower Mnembo River, Malawi-Mozambique

    Leanda M. Delaney
    Abstract Endorheic Lake Chilwa is one of the most productive lakes for fisheries in Africa. High human population densities and agricultural practices in the Chilwa catchment have been linked to observed declines of the annual fish catch in the lake. The Mnembo River is a major inflow into Lake Chilwa which has received little scientific study to date. In 2003/2004, fish diversity, abundance and distribution were monitored monthly at three sites in the Mnembo River. Twelve fish species were collected, a subset of the fourteen fish species present in Lake Chilwa. Although Barbus spp. were the most abundant species sampled in the Mnembo, total biomass was higher for Labeo cylindricus (6709 and 10,434 g, respectively). Total biomass of Pareutropius longifilis (1741 g) and Brycinus imberi (1174 g) were also high in the river. Catches of Barbus and Labeo were highly correlated (r = 0.763). Compared with other inflows into Lake Chilwa (Likangala and Domasi), the Mnembo River appears to be less adversely influenced by human populations, with high abundance of Barbus and strong presence of the riverine species Labeo, Pareutropius and Brycinus. Résumé Le lac Chilwa est endorhéique. C'est un des lacs les plus productifs d'Afrique. De fortes densités de population humaine et les pratiques agricoles du bassin de Chilwa sont liées au déclin des prises annuelles de poisson que l'on a observé. La rivière Mnembo est un des affluents majeurs du lac; elle a fait l'objet de peu d'études scientifiques jusqu'à présent. En 2003,2004, on a surveillé la diversité, l'abondance et la distribution du poisson de façon régulière, chaque mois, à trois endroits le long de la Mnembo. On a récolté douze espèces de poissons, une partie des quatorze espèces trouvées dans le lac Chilwa. Même si Barbus spp. était l'espèce la plus abondante récoltée dans la Mnembo, la biomasse totale était plus forte pour Labeo cylindricus (6.709 g et 10.434 g, respectivement). La biomasse totale de Pareutropius longifilis (1.741 g) et deBrycinus imberi (1.174 g) était aussi élevée dans la rivière. Les prises de Barbus et de Labeoétaient en forte corrélation (r = 0,763). Comparée aux autres affluents du lac Chilwa (Likangala et Domasi), la Mnembo semble moins souffrir de l'influence des populations humaines, avec la grande abondance de Barbus et une présence affirmée des espèces de rivage que sont Labeo, Pareutropius et Brycinus. [source]

    Towards a fuller understanding of mosquito behaviour: use of electrocuting grids to compare the odour-orientated responses of Anopheles arabiensis and An. quadriannulatus in the field

    S. J. TORR
    Abstract The epidemiological role of and control options for any mosquito species depend on its degree of ,anthropophily'. However, the behavioural basis of this term is poorly understood. Accordingly, studies in Zimbabwe quantified the effects of natural odours from cattle and humans, and synthetic components of these odours, on the attraction, entry and landing responses of Anopheles arabiensis Giles (Diptera: Culicidae) and Anopheles quadriannulatus Theobald. The numbers of mosquitoes attracted to human or cattle odour were compared using electrocuting nets (E-nets), and entry responses were gauged by the catch from an odour-baited entry trap (OBET) relative to that from an odour-baited E-net. Landing responses were estimated by comparing the catches from E-nets and cloth targets covered with an electrocuting grid. For An. arabiensis, E-nets baited with odour from a single ox or a single man caught similar numbers, and increasing the dose of human odour from one to three men increased the catch four-fold. For An. quadriannulatus, catches from E-nets increased up to six-fold in the progression: man, three men, ox, and man + ox, with catch being correlated with bait mass. Entry responses of An. arabiensis were stronger with human odour (entry response 62%) than with ox odour (6%) or a mixture of cattle and human odours (15%). For An. quadriannulatus, the entry response was low (< 2%) with both cattle and human odour. Anopheles arabiensis did not exhibit a strong entry response to carbon dioxide (CO2) (0.2,2 L/min). The trends observed using OBETs and E-nets also applied to mosquitoes approaching and entering a hut. Catches from an electrocuting target baited with either CO2 or a blend of acetone, 1-octen-3-ol, 4-methylphenol and 3-n-propylphenol , components of natural ox odour , showed that virtually all mosquitoes arriving there alighted on it. The propensity of An. arabiensis to enter human habitation seemed to be mediated by odours other than CO2 alone. Characterizing ,anthropophily' by comparing the numbers of mosquitoes caught by traps baited with different host odours can lead to spurious conclusions; OBETs baited with human odour caught around two to four times more An. arabiensis than cattle-baited OBETs, whereas a human-baited E-net caught less (, 0.7) An. arabiensis than a cattle-baited E-net. Similar caution is warranted for other species of mosquito vectors. A fuller understanding of how to exploit mosquito behaviour for control and surveys requires wider approaches and more use of appropriate tools. [source]

    Long-term changes of aphid vectors of Barley yellow dwarf viruses in north-eastern Italy (Friuli-Venezia Giulia)

    P.G. Coceano
    Abstract Migrations of aphid vectors of Barley yellow dwarf viruses (BYDV) were monitored using a Rothamsted Insect Survey suction trap in Friuli-Venezia Giulia (north-eastern Italy). Catches from 1983 to 2002 were studied for trends, correlations of total catches of each year with those of previous years, correlations between the autumn and the spring + summer catches of the same year and between spring + summer catches of one year with catches of the previous autumn. Infectivity of autumn alates was studied using biological tests, and infectivity indexes were calculated for all vector species and for Rhopalosiphum padi alone. Colonisation of barley and proportion of infected plants were checked in a field close to the suction trap from 1992 to 2002 and related to trap catches. Catches were also correlated to acreage dedicated to cereal and fodder crops in the region. During the 20 years, 15 BYDV vector species were caught in the trap, but only five species were found consistently colonising barley plants during autumn. R. padi was the most numerous species in catches, while Sitobion avenae was the predominant colonising species in the barley field. Relatively to R. padi, S. avenae colonies were about six times more numerous than expected from catches. The yearly abundance of catches of most species did not change significantly during the 20 years, with a few exceptions, significantly correlated to changes in the acreage dedicated to cereal and fodder crops. There was a significant decrease of the autumn catches of both R. padi and the total of BYDV vectors. [source]

    Response of Culicoides spp. (Diptera: Ceratopogonidae) to light-emitting diodes

    Alan L Bishop
    Abstract Light traps with incandescent globes are used in a national monitoring program to detect the presence of Culicoides spp. responsible for the transmission of viruses to livestock and native animals. Recent events have suggested that the efficiency of these traps should be reconsidered and possibly improved. Subsequently, the response of eight species of Culicoides to light-emitting diodes (LEDs) was determined at two locations in New South Wales. Culicoides austropalpalis Lee & Reye, C. bunrooiensis Lee & Reye and C. marksi Lee & Reye were attracted to blue light. Responses to blue and green light could not be separated for C. bundyensis Lee & Reye, C. dycei Lee & Reye, C. nattiensis Lee & Reye and C. victoriae Macfie. Culicoides brevitarsis Kieffer was significantly attracted to green light. This species is the major vector of Akabane and bluetongue viruses in Australia. These responses were all significantly greater than the responses to the incandescent lights currently used in the light traps. The response to red light was less than the response to incandescent light for all species. Catches of C. brevitarsis were also related to the intensity of the green LEDs. These were more effective than the currently used incandescent globes at intensities between 46% and 142% of the incandescent intensity. [source]

    Evaluating the Predicted Local Extinction of a Once-Common Mouse

    Chicago; declinación de especies comunes; extinción pronosticada; Peromyscus leucopus; Peromyscus maniculatus bairdii Abstract:,In an earlier paper (Pergams & Nyberg 2001) we found that the proportion of the prairie deer mouse (Peromyscus maniculatus bairdii), among all local Peromyscus museum specimens collected in the Chicago region, had significantly declined over time. This proportion changed from about 50% before 1900 to <10% in the last 25 years. Based on this proportion a regression model predicted the local extinction of the prairie deer mouse in 2009. To evaluate that prediction, we estimated current deer mouse abundance by live trapping small mammals at 15 preserves in Cook and Lake counties, Illinois (USA) at which prairie deer mice had previously been caught or that still contained their preferred open habitat. In 1900 trap nights, 477 mammals were caught, including 251 white-footed mice (P. leucopus), but only one prairie deer mouse. The observed proportion of Peromyscus that were prairie deer mice, 0.4%, was even lower than the 4.5% predicted for 2000. Here we also introduce a simple, new community proportions model, which for any given geographic region compares the proportions of species recently caught with the proportions of species in museums. We compared proportions of seven species collected in Cook and Lake counties and examined by Hoffmeister (1989) with proportions of these species that we caught. Ten percent of the museum community was prairie deer mice, but only 0.2% of our catch was. The current local scarcity of the prairie deer mouse is consistent with the regression-based prediction of its eminent local extinction. More conservation attention should be paid to changes in relative abundance of once-common species. Resumen:,En un artículo previo (Pergams & Nyberg 2001) encontramos que la proporción de Peromyscus maniculatus bairdii, entre todos los especimenes de museo de Peromyscus recolectados en la región de Chicago, había declinado significativamente. Esta proporción cambió de 50% antes de 1900 a <10% en los últimos 25 años. Con base en esta proporción, un modelo de regresión pronosticó la extinción local de P. m. bairdii en 2009. Para evaluar esa predicción, estimamos la abundancia actual de P. m. bairdii mediante el trampeo de mamíferos pequeños en 25 reservas en los condados Cook y Lake, Illinois (E.U.A.) en las que se había capturado a P. m. bairdii previamente o que aun contenían su hábitat abierto preferido. En 1900 noches-trampa, capturamos a 477 mamíferos, incluyendo a 251 P. leucopus pero solo a un P. m. bairdii. La proporción observada de P. m. bairdii, 0.4%, fue menor a 4.5% pronosticado para 2000. Aquí también introducimos un modelo, nuevo y sencillo, de proporciones de la comunidad que compara, para cualquier región geográfica, las proporciones de especies recientemente capturadas con la proporciones de especies en los museos. Comparamos las proporciones de siete especies recolectadas en los condados Cook y Lake y examinadas por Hoffmeister (1989) con las proporciones de especies que capturamos. Diez por ciento de la comunidad de museos era P. m. bairdii, pero solo 0.2% de nuestra muestra lo fue. La actual escasez local de P. m. bairdii es consistente con la predicción de su inminente extinción local con base en la regresión. La conservación debe prestar mayor atención a los cambios en la abundancia relativa de una especie anteriormente común. [source]

    Genetic Identification of Pelagic Shark Body Parts for Conservation and Trade Monitoring

    Mahmood Shivji
    Difficulties with the identification of many commonly fished sharks and their body parts has resulted in a global dearth of catch and trade information, making reliable assessment of exploitation effects and conservation needs for individual species nearly impossible. We developed and tested a highly streamlined molecular genetic approach based on species-specific, polymerase-chain-reaction primers in an eight-primer multiplex format to discriminate simultaneously between body parts from six shark species common in worldwide pelagic fisheries. The species-specific primers are based on DNA sequence differences among species in the nuclear ribosomal internal transcribed spacer 2 locus. The primers and multiplex format accurately and sensitively distinguished samples from each of three lamnid ( Isurus oxyrinchus, Isurus paucus, and Lamna nasus) and three carcharhinid ( Prionace glauca, Carcharhinus obscurus, and Carcharhinus falciformis) species from all but one other shark species encountered in the North Atlantic fishery. Furthermore, the three lamnid primers were robust enough in their discriminatory power to be useful for species diagnosis on a global scale. Preliminary testing of dried fins from Asian and Mediterranean commercial markets suggests that our genetic approach will be useful for determining the species of origin of detached fins, thus allowing the monitoring of trade in shark fins for conservation assessment. Our approach will also facilitate detection of products from protected and other at-risk shark species and may prove useful as a model for development of the high-throughput, genetic, species-diagnosis methods typically required in conservation and management contexts. Resumen: La conservación y manejo de tiburones fundamentado a nivel de especie es una necesidad imperativa debido a la creciente demanda de aletas de tiburón y el reconocimiento de que las especies individuales de tiburones responden de manera distinta a la explotación. Las dificultades para la identificación de muchos tiburones capturados comúnmente, así como de partes de su cuerpo, han resultado en una escasez global de información sobre capturas y comercialización, haciendo casi imposible el poder realizar evaluaciones de los efectos de la explotación y de las necesidades de conservación. Desarrollamos y evaluamos un método altamente estilizado de genética molecular basado en detonadores de la reacción en cadena de la polimerasa, especie-específicos, en un formato múltiple de ocho detonadores para discriminar simultáneamente entre las partes del cuerpo de seis especies de tiburones provenientes de pesquerías pelágicas mundiales comunes. Los detonadores especie-específicos están basados en diferencias en las secuencias de ADN entre especies del locus espaciador 2 nuclear, ribosomal, transcrito. Los detonadores y el formato múltiple distinguen muestras con precisión y sensitividad de cada uno de los tres lámnidos ( Isurus oxyrinchus, Isurus paucus y Lamna nasus) y tres especies de carcarínidos ( Prionace glauca, Carcharhinus obscurus y Carcharhinus falciformis) especies todas encontradas en las pesquerías de Norteamérica, excepto una. Mas aún, los detonadores de los tres lamnidos fueron lo suficientemente robustos en su poder discriminante como para ser usados para el diagnóstico de especies a escala mundial. Las pruebas preliminares de aletas secas de los mercados comerciales de Asia y el Mediterráneo sugieren que nuestro método genético puede ser útil para determinar la especie de origen de las aletas separadas, permitiendo así usar el monitoreo de las aletas de tiburón para evaluaciones de conservación. Nuestro método también podría facilitar la detección de productos provenientes de especies protegidas o en riesgo y podría resultar útil como un modelo para el desarrollo de métodos genéticos de alto rendimiento para el diagnóstico de especies, métodos típicamente requeridos en los contextos de conservación y manejo. [source]

    Partitioned Nature, Privileged Knowledge: Community-based Conservation in Tanzania

    Mara Goldman
    Community Based Conservation (CBC) has become the catch,all solution to the social and ecological problems plaguing traditional top,down, protectionist conservation approaches. CBC has been particularly popular throughout Africa as a way to gain local support for wildlife conservation measures that have previously excluded local people and their development needs. This article shows that, despite the rhetoric of devolution and participation associated with new CBC models, conservation planning in Tanzania remains a top,down endeavour, with communities and their specialized socio,ecological knowledge delegated to the margins. In addition to the difficulties associated with the transfer of power from state to community hands, CBC also poses complex challenges to the culture or institution of conservation. Using the example of the Tarangire,Manyara ecosystem, the author shows how local knowledge and the complexities of ecological processes challenge the conventional zone,based conservation models, and argues that the insights of local Maasai knowledge claims could better reflect the ecological and social goals of the new CBC rhetoric. [source]

    Smaller and more numerous harvesting gaps emulate natural forest disturbances: a biodiversity test case using rove beetles (Coleoptera, Staphylinidae)

    Jan Klimaszewski
    ABSTRACT Aim To evaluate changes in the abundance, species richness and community composition of rove beetles (Coleoptera, Staphylinidae) in response to three configurations of experimental gap cuts and to the effects of ground scarification in early succession yellow birch-dominated boreal forest. In each experimental treatment, total forest removed was held constant (35% removal by partial cutting with a concomitant decrease in gap size) but the total number of gaps was increased (two, four and eight gaps, respectively), resulting in an experimental increase in the total amount of ,edge' within each stand. Location Early succession yellow birch-dominated forests, Quebec, Canada. Methods Pitfall traps, ANOVA, MIXED procedure in sas®, post hoc Tukey's adjustment, rarefaction estimates, sum-of-squares and distance-based multivariate regression trees (ssMRT, dbMRT). Results Estimates of species richness using rarefaction were highest in clearcut and two-gap treatments, decreased in smaller and more numerous gaps and were significantly higher in scarified areas than in unscarified areas. ANOVA indicated a significant impact of harvesting on the overall standardized catch. Post hoc Tukey's tests indicated that the total catch of all rove beetles was significantly higher in uncut forests than in the treated areas. Both sum-of-squares and distance-based multivariate regression trees indicated that community structure of rove beetles differed among treatments. Assemblages were grouped into (a) control plots, (b) four- and eight-gap treatments and (c) two-gap and clearcut treatments. Main conclusions Rove beetle composition responded significantly to increasing gap size. Composition among intermediate and small-sized gap treatments (four- and eight-gap treatments) was more similar to uncut control forests than were larger gap treatments (two-gap) and clearcuts. Effects of scarification were nested within the harvested treatments. When the total area of forest removed is held constant, smaller, more numerous gaps are more similar to uncut control stands than to larger gaps and falls more closely within the natural forest heterogeneity. [source]

    Ground beetle responses to patch retention harvesting in high elevation forests of British Columbia

    ECOGRAPHY, Issue 5 2004
    Jeffrey P. Lemieux
    The effect of a forest harvesting system whereby small (typically 0.1,2.0 ha) patches of standing timber are retained inside of harvests, was compared to conventional clearcutting for its effect on ground beetle assemblages. Two seasons of pitfall trapping entailed 46,451 trap days, and yielded 15,799 individuals of 28 species; abundance was dominated by four species comprising 92.4% of the catch. Most species were known to have wide geographic distributions in Canada and Alaska but many species seemed to respond to disturbance on a site-specific basis. Contrary to findings of similar studies, no species could be characterized as "mature-forest specialists", or "forest generalists". Forest patches and edge habitats immediately inside the forest canopy contained assemblages more closely related to mature forest than to cleared areas. Harvested areas with patches yielded catches distinct from typical clearcuts, based primarily on changes in abundance of one common species. Climatic regimes and landscape disturbance levels were the two important factors distinguishing our study from others, and we have suggested that these may influence the degree to which patches are an effective conservation tool. [source]

    Is optimal foraging a realistic expectation in orb-web spiders?

    Abstract 1.,Explanations for web relocation invoking optimal foraging require reliable differentiation between individual sites and overall habitat quality. We characterised natural conditions of resource variability over 20 days in artificial webs of the orb-web spider Gasteracantha fornicata to examine this requirement. 2.,Variability in catch success was high. Day-to-day catch success in 90% (18/20) catch sites fitted negative binomial distributions, whereas 10% fitted Poisson distributions. Considered across trap sites (overall habitat), variance in catch success increased proportionally faster than the mean (i.e. Taylor's Power Law, variance = 0.54mean1.764). 3.,We compared the confidence intervals for the expected cumulative catch in randomly drawn sequential samples from a frequency distribution representing the overall habitat (based on the parameters for Taylor's power law) and the frequency distribution of expected cumulative catch within each individual catch site [via randomisation based on the mean and negative binomial exponent (k)]. 4.,In all cases and across all sample sizes, median values for the power to differentiate habitat and catch sites never exceeded 0.2, suggesting that principles involved in optimal foraging, if operating, must be accompanied by a very high degree of uncertainty. 5.,Under conditions of high resource variability, many days must be spent in a single catch site if movement decisions are based on an ability to differentiate current catch site from overall habitat. Empirical evidence suggests this is never met. This may explain why proximal mechanisms that illicit quickly resolved behavioural responses have been more successful in describing web relocation patterns than those associated with optimal foraging. [source]

    Tributaries influence recruitment of fish in large rivers

    B. M. Pracheil
    Abstract,,, Recent work demonstrates that tributary inputs are important community reorganisation points for river biota; however, no studies have examined the long-term effects of tributary inputs on fish population dynamics. This study examines nearly 40 years of young-of-year (yoy) paddlefish recruitment data to investigate the hypothesis that tributaries influence mainstem fish population dynamics. We generated hydrological variables from daily mean flow data (1965,2007) from an impounded reach of the mainstem Missouri River and from the Niobrara River, a relatively unaltered tributary, using Indicators of Hydrologic Alteration software. Three multiple regression models using natural-log transformed catch per unit effort (log cpue) as the response variable were created using (1) Missouri River-only flow variables, (2) Niobrara River-only flow variables and (3) Missouri River and Niobrara River flow variables. Flow variables from the Niobrara River explain a greater proportion of yoy paddlefish log cpue variability demonstrating that tributaries can positively impact fish population dynamics in altered rivers. [source]

    Fish distribution and diet in relation to the invasive macrophyte Lagarosiphon major in the littoral zone of Lake Dunstan, New Zealand

    T. O. Bickel
    Abstract,,, Invasive macrophytes are usually associated with negative impacts on habitat quality and a threat to native biodiversity. However, they might provide the same beneficial functions of native macrophytes, i.e., the provision of food and shelter for fish, in the absence of native macrophytes. To assess the value of the invasive macrophyte Lagarosiphon major as a fish habitat, we investigated the spatio,temporal variation in the distribution of a small littoral fish species (common bully) in the littoral of Lake Dunstan, a New Zealand hydro lake. Large- and fine-scale common bully distribution could partly be explained by the occurrence of dense L. major stands. Additionally, variability in catch per unit effort was partly explained by season and recruitment. Diet analysis indicated that common bullies in the Lagarosiphon-dominated littoral fed on invertebrates (Mollusca, Trichoptera, Chironomidae) found on exotic L. major, therefore suggesting its role as a food provider in the system. These results indicated that invasive macrophytes can provide important ecosystem functions in disturbed habitats that are otherwise devoid of native macrophytes. Any macrophyte management strategy should therefore carefully consider the costs and benefits associated with macrophyte control. [source]

    Different longitudinal distribution patterns of native white-spotted charr and non-native brown trout in Monbetsu stream, Hokkaido, northern Japan

    K. Hasegawa
    Abstract, This study focused on longitudinal distribution patterns of native white-spotted charr and non-native brown trout in a mountainous stream in Hokkaido, Japan. Brown trout ratio, which is the proportion of brown trout in the catch of salmonids, was decreasing from downstream to upstream. Brown trout ratio correlated negatively with water temperature. Thus, our results suggested that temperature may influence the possible competition between native white-spotted charr and non-native brown trout. [source]

    Habitat use and population structure of four native minnows (family Cyprinidae) in the upper Missouri and lower Yellowstone rivers, North Dakota (USA)

    T. L. Welker
    Abstract,,, In 1997 and 1998, sampling was conducted on the Missouri and Yellowstone rivers, North Dakota, to obtain information on the distribution, abundance, and habitat use of the flathead chub (Platygobio gracilis Richardson), sicklefin chub (Macrhybopsis meeki Jordan & Evermann), sturgeon chub (Macrhybopsis gelida Girard), and western silvery minnow (Hybognathus argyritis Girard), four declining fish species (family Cyprinidae) native to the Missouri River basin, USA. The study area consisted of four distinct river segments near the confluence of the Missouri and Yellowstone rivers , three moderately altered segments that were influenced by a main-stem dam and one quasi-natural segment. One moderately altered segment was located at the confluence of the two rivers (mixing-zone segment (MZS)). The other two moderately altered segments were in the Missouri River adjacent to the MZS and extended up-river (above-confluence segment (ACS)) and down-river (below-confluence segment (BCS)) from this segment. The quasi-natural segment (Yellowstone River segment (YRS)) extended up-river from the MZS in the Yellowstone River. Catch rates with the trawl for sicklefin chub and sturgeon chub and catch rates with the bag seine for flathead chub and western silvery minnow were highest in the BCS and YRS. Most sicklefin and sturgeon chubs were captured in the deep, high-velocity main channel habitat with the trawl (sicklefin chub, 97%; sturgeon chub, 85%), whereas most flathead chub and western silvery minnow were captured in the shallow, low-velocity channel border habitat with the bag seine (flathead chub, 99%; western silvery minnow, 98%). Best-fit regression models correctly predicted the presence or absence of sicklefin chub, flathead chub, and western silvery minnow more than 80% of the time. Sturgeon chub presence and absence were predicted correctly 55% of the time. Best-fit regression models fit to fish number data for flathead chub, sicklefin chub, and sturgeon chub and fish catch-per-unit-effort (CPUE) data for flathead chub also provided good fits, with R2 values ranging from 0.32 to 0.55 (P < 0.0001). The higher density and catch of the four native minnows in the YRS and BCS suggest that these two segments are better habitat than the ACS and MZS. [source]

    Growth and mortality of prairie stream fishes: relations with fish community and instream habitat characteristics

    M. C. Quist
    Abstract , Few studies have been conducted to describe the age structure, growth rates and mortality of fishes in small stream ecosystems. The purpose of this study was therefore to determine age structure, growth rates and mortality (i.e., total annual mortality and, age-specific mortality) of central stonerollers Campostoma anomalum, creek chubs Semotilus atromaculatus, red shiners Cyprinella lutrensis and green sunfish Lepomis cyanellus from 13 streams on Fort Riley Military Reservation, Kansas, using incremental growth analysis. Further, we were interested in determining the influence of fish community and instream habitat characteristics on growth rates. The age structure of central stonerollers, creek chubs, and red shiners was dominated by young individuals (i.e., less than age 2); however, over 60% of the green sunfish were age 2 to age 4. Mean total annual mortality was >60% for cyprinids and averaged approximately 44% for green sunfish. The age-specific mortality of central stonerollers and red shiners was generally less than 45% between age 0 and 1 and increased to over 85% for fishes greater than age 1. Fish community characteristics (e.g., catch per unit effort of trophic guilds) and chemical habitat (e.g., total phosphorous) were not related to growth rates (P>0.05). Growth of central stonerollers was not significantly correlated with physical habitat (P>0.05). However, the growth increments of creek chubs, red shiners, and green sunfish were related to the amount of woody debris (e.g., total woody debris, log complex habitat; r>0.60; P,0.05). The results of this study provide important information on the population dynamic rate functions of cyprinid and green sunfish populations in small prairie streams. Furthermore, these data suggest that woody debris is important habitat influencing growth of stream fishes., [source]

    Geographic variation in the field response of male European pine sawflies, Neodiprion sertifer, to different pheromone stereoisomers and esters

    O. Anderbrant
    Abstract The European pine sawfly, Neodiprion sertifer (Geoffroy) (Hymenoptera: Diprionidae), is a widespread and economically important forest insect. The sex pheromone communication system of this species has been previously investigated in North America, Japan and Europe, with the acetate or propionate of the alcohol (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol) shown to be the main pheromone component. In some locations, male attraction either increased or decreased by the addition of the (2S,3R,7R)-diprionyl acetate isomer. However, these studies were made with different batches of synthetic pheromones, with different types of traps and according to different procedures, so the observed differences might not reflect true geographic variation. Here we investigate the geographic pattern of male sawfly response by using identical chemicals, traps and experimental procedures at eight field sites ranging from Japan in the east to Canada in the west. We found an increased inhibitory effect of the (2S,3R,7R)-isomer from Japan and Siberia to Europe. At the eastern sites, increasing amounts of the (2S,3R,7R)-isomer up to and equal to the amount of the (2S,3S,7S )-isomer, did not influence the trap catch, whereas at sites in Europe, as little as 1% of the (2S,3R,7R)-isomer almost completely inhibited the attraction. The response of the North American population was intermediate. The only site in which the (2S,3R,7R)-isomer was essential for the attraction of males was in Siberia. A similar pattern was found for the (2S,3R,7S)-isomer. Both the acetate and the propionate form of the (2S,3S,7S)-isomer were attractive by themselves in Japan, Europe and North America, and neither the (2S,3R,7S)-isomer nor the (2S,3R,7R)-isomer alone were attractive, in the acetate or propionate form. We discuss the significance of our findings for the development of more efficient monitoring schemes and for the causes of population divergence and speciation in the European pine sawfly. [source]

    Population persistence of the parasitoid fly Zaira cinerea (Fallén) (Diptera: Tachinidae) utilizing multiple host carabid beetles with different seasonality and quality

    Atsushi OHWAKI
    Abstract Zaira cinerea (Fallén) is a parasitoid fly (Diptera: Tachinidae) that attacks adult carabid beetles. To better understand mechanisms of population persistence in this species, we examined seasonality of host beetle abundance, the frequency of parasitism, and the timing of fly eclosion. In addition, we evaluated host quality using numbers of larvae or puparia per individual beetle as a measure of quality. The fly parasitized only large carabids (,15 mm body length); the lengths of fly puparia reached 7.4,10.8 mm during development in beetle abdomens, and larger hosts are likely essential. Of the 18 large carabid species collected in this study, we chose two, Carabus maiyasanus Bates and Leptocarabus procerulus (Bates), because they were large and abundant (87% of total catch). The two carabids had different phonologies; C. maiyasanus was abundant from spring to summer, and its abundance dropped sharply in autumn, while L. procerulus was abundant in autumn and rare from spring to summer except July. Parasitism was observed in all the months from May to November except June, and adult flies eclosed more than once a year (in early summer, late summer, and mid-autumn), indicating that the species is multivoltine. Host quality of L. procerulus was higher than that of C. maiyasanus. Carabus maiyasanus was mainly used as a host from spring to summer, and L. procerulus was used in autumn. Thus, adult beetles of one or both species are available over most of spring, summer, and autumn, allowing population persistence of this fly species over time. [source]

    Can circle hook use benefit billfishes?

    FISH AND FISHERIES, Issue 2 2009
    Joseph E Serafy
    Abstract We performed a quantitative review to evaluate circle hook use in recreational and commercial hook-and-line fisheries that interact with billfishes (Family: Istiophoridae). Specifically, we scrutinized the findings of 11 recent empirical studies that reported, on a species-specific basis, side-by-side measures of circle vs. J-hook fishing performance: catch, mortality, deep-hooking and bleeding rates. Of the 30 total comparisons extracted from the literature that satisfied our inclusion criteria, 13 indicated significant differences between hook types for the specific metric compared. No study reported significant billfish catch rate differences between hook types. However, when significant differences between hook types were found, higher mortality rates and higher rates of deep-hooking and bleeding were associated with J-hooks relative to circle hooks. We conclude that empirical evidence is sufficient to promote circle hook use in almost all hook-and-line fishery sectors that typically interact with istiophorids. However, billfish conservation benefits will only be realized if fishers use unmodified circle hooks, commit to releasing live fish and take other appropriate measures which maximize post-release survival. While there may be fishing modes where circle hook effects are negative, for billfish conservation, we recommend managers grant exceptions to circle hook use only when experimental results support such a practice. [source]

    How do individual transferable quotas affect marine ecosystems?

    FISH AND FISHERIES, Issue 1 2009
    Trevor A Branch
    Abstract Published papers were reviewed to assess ecosystem impacts of individual transferable quotas (ITQs) and other dedicated access systems. Under ITQs, quota shares increase with higher abundance levels, thus fishers may request lower total allowable catches (TACs) and pay for monitoring and research that improves fishery sustainability. Mortality on target species generally declines because catches are closer to TACs and because ghost fishing through lost and abandoned gear decreases. High-grading and discarding often decline, but may increase if landings (and not catches) count against ITQs and when there is little at-sea enforcement. Overall, ITQs positively impact target species, although collapses can occur if TACs are set too high or if catches are routinely allowed to exceed TACs. Fishing pressure may increase on non-ITQ species because of spillover from ITQ fisheries, and in cases where fishers anticipate that future ITQ allocations will be based on catch history and therefore increase their current catches. Ecosystem and habitat impacts of ITQs were only sparsely covered in the literature and were difficult to assess: ITQs often lead to changes in total fishing effort (both positive and negative), spatial shifts in effort, and fishing gear modifications. Stock assessments may be complicated by changes in the relationship between catch per unit effort, and abundance, but ITQ participants will often assist in improving data collection and stock assessments. Overall, ITQs have largely positive effects on target species, but mixed or unknown effects on non-target fisheries and the overall ecosystem. Favourable outcomes were linked to sustainable TACs and effective enforcement. [source]

    The enhancement of abalone stocks: lessons from Japanese case studies

    FISH AND FISHERIES, Issue 3 2008
    Katsuyuki Hamasaki
    Abstract The dramatic declines in abalone Haliotis spp. fishery production have been documented all over the world. Release of hatchery-reared juveniles into natural habitats has been considered as one measure to sustain and/or augment the current fishery production of abalone, as well as to restore collapsed abalone stocks. However, attempts at abalone release programmes have only been undertaken at experimental scales, except for Japan, where large-scale stock enhancement programmes for abalone have been undertaken since late 1960s. To evaluate the potential of stock enhancement for abalone, we analysed the release surveys of 13 case studies in Japan in terms of the overall recapture rate (number of recaptures through a lifetime/number of juveniles released), yield per release (YPR, yields from released individuals), the economic efficiency of releases (ratio of income from recaptured abalone to release cost) for each release year, and the contribution of hatchery releases to total catches for each fishing year. The average estimates for overall recapture rates (0.014,0.238) and YPR (3.1,60.3 g/individual) varied between locations and release years. The economic efficiency was estimated at 0.4,6.2. The released abalone contributed 6.9,83.5% to total catches. Hatchery releases could augment total production at some locations, but the success of release programmes would be limited by the carrying capacity at release areas, because density-dependent mortality occurred following releases in some cases. Throughout Japan, the annual catch of abalone has continuously declined from ,6500 t in 1970 to ,2000 t in the mid-1990s, despite the increase in the number of hatchery releases. Based on the estimates for YPR, the magnitude of the abalone releases on a national scale has not been sufficiently large to sustain the total production of Japanese abalone, which has primarily fluctuated according to the abundances of wild populations. Our results suggest that releases should be targeted at local populations in regions where stock enhancement is predicted to have the greatest chance of success, and the magnitude of releases should be considered carefully and determined for each region by taking the local carrying capacity into account. We also address the future prospects of abalone stock enhancement. [source]