يعرض 1 - 10 نتائج من 171 نتيجة بحث عن '"cockle"', وقت الاستعلام: 0.73s تنقيح النتائج
  1. 1
    دورية أكاديمية

    المصدر: Journal of Marine Science and Engineering, Vol 12, Iss 1, p 48 (2023)

    الوصف: The clam fishery in northwestern Mexico encompasses the mangrove cockle Anadara tuberculosa. It is extracted manually, at low tides and between the roots of mangroves. Biological samplings were carried out in Estero Las Lajitas, Sinaloa, from May 2021 to April 2022. A total of 661 A. tuberculosa organisms were analyzed, of which 126 were males, were 363 females and 172 were undifferentiated, yielding a statistically different overall sex ratio between females and males (1♀:0.3♂) (X2 = 113.19; p < 0.05). The length–weight relationship showed a potential type (W = 0.0002L3.125) (95% CI 3.027–3.222 for b). To determine the growth of the species, five models were employed: von Bertalanffy, Gompertz, Logistic, Richards, and Gompertz using an oscillatory component (GO). The Akaike Corrected Information Index for Small Samples (AICC) was used. The GO model yielded the lowest AICC (L∞ = 80.98 mm 95% CI 77.59–84.36, k = 1.02 year−1 95% CI 0.89–1.16), a low growth oscillation intensity (C = 0.03), and slower growth in August (WP = 1.67). The Logistic and Gompertz models were used to calculate the size-at-maturity (L50%). Gompertz obtained the lowest AICC with L50% = 32.53 mm (95% CI 30.67–34.31). Considering the lack of biological information and the parameters generated in the present investigation, as regards A. tuberculosa on the coast of Sinaloa, Mexico, its dissemination is essential for the adequate management of the fishery.

    وصف الملف: electronic resource

  2. 2
    دورية أكاديمية

    المصدر: Jurnal Kelautan Tropis, Vol 20, Iss 2, Pp 84-89 (2017)

    الوصف: The present study was conducted to inventory the cockles (bivalve) in coastal waters between Semarang to Demak. The samples were collected by bottom trawl modification (dragger) around those areas. The results were found ten various cockles there were Anadara granosa, A. pilula, A. gubernaculum, A. inaequivalvis, Pharella javanica, Paphia undulate, Marcia hiantina, Harvella plicataria, Mactra violacea, and Placuna placenta. Meanwhile the waters quality in the in this areas still support to organisms to survive based on the standard water quality from Indonesian Ministry of Environmental. Tujuan penelitian ini adalah untuk menginventarisasi jenis jenis kerang yang ada di perairan antara Semarang dan Demak. Sampel diambil dengan trawl dasar modivikasi (dragger) sekitar perairan tersebut. Hasil penelitian menunjukakan beberapa jenis kerang didapat seperti: Anadara granosa, A. pilula, A. gubernaculum, A. inaequivalvis, Pharella javanica, Paphia undulate, Marcia hiantina, Harvella plicataria, Mactra violacea, and Placuna placenta. Berdasar Kepmen Lingkungan Hidup kualitas perairan yang ada di daerah tersebut dapat dikatakan masih mendukung untuk kehidupan organisme.

    وصف الملف: electronic resource

  3. 3
    دورية أكاديمية

    المصدر: Jurnal Kelautan Tropis, Vol 20, Iss 1, Pp 65-71 (2017)

    الوصف: This study aims to determine to determine the species composition, abundance and community structure of phytoplankton in shellfish aquaculture ponds blood (Anadara granosa) in Menco, District Wedung, District Demak.Metode used in this study is Diskriptif method, determination of the location of the study is purposive sampling Methods, namely the determination of the sampling locations should be based on consideration, the station I to III of the sampling stations representing keseluruan research area. Marine research station is Blood Shellfish Farming in Hamlet Menco. Station is divided into three stations, with making four periods. Environmental parameters taken include: salinity, temperature, pH, DO, nitrate, phosphate, dissolved oxygen, organic materials. The results of the study, found 19 genera of phytoplankton. Phytoplankton abundance 2596-18844 cells / L. Diversity index (H ') based on the total period ranged from 1.098 to 1.837. On January 18-March 3, 2014, categorized into the diversity index medium. Uniformity index (e) the entire period ranged from 0.616 to 0.999. Fitoplankton atau mikroalga merupakan makanan utama kerang di tambak. Penelitian ini bertujuan untuk mengetahui komposisi jenis, kelimpahan, dan struktur komunitas fitoplankton pada tambak budidaya kerang darah (Anadara granosa) di Menco, Kecamatan Wedung, Kabupaten Demak. M etode yang digunakan dalam penelitian ini adalah metode Deskriptif. Sampel fitoplankton diambil dari Tambak Kerang Darah selama empat periode. Parameter lingkungan sebagai data penunjang adalah salinitas, suhu, pH, DO, nitrat, fosfat, oksigen terlarut, bahan organik. Hasil penelitian menjunjukkan terdapat 19 genus fitoplankton, dengan kelimpahan 2.5-18.8x103sel.L-1. Indeks keanekaragaman (H’) berdasarkan total keseluruhan periode berkisar antara 1,098-1,837. Pada tanggal 18 Januari-3 Maret 2014, dikategorikan masuk dalam indeks keanekaragaman sedang. Indeks keseragaman (e) keseluruhan periode berkisar antara 0,616–0,999.

    وصف الملف: electronic resource

  4. 4

    المصدر: Acta Oceanologica Sinica. 40:89-97

    الوصف: The population parameters of blood cockles, Tegillarca granosa in the intertidal zone of Marudu Bay, Sabah, Malaysia were investigated based on monthly length-weight frequency data (July 2017 to June 2018). A total of 279 cockle individuals with shell length and weight ranging from 27.7 mm to 82.2 mm and 13.11 g to 192.7 g were subjected to analysis. T. granosa in Marudu Bay showed a consistent moderately high condition index 4.98±0.86 throughout the year. The exponent b of the length-weight relationship was 2.6 demonstrating negative allometric growth. The estimated asymptotic length (L∞), growth coefficient (K) and growth performance (ϕ) of the T. granosa population in Marudu Bay were estimated at 86.68 mm, 0.98 a−1 and 3.87, respectively. The observed maximum shell length was 82.55 mm and the predicted maximum shell length was 84.44 mm with estimated maximum life span (tmax) of 3.06 years. The estimated mean lengths at the end of 2, 4, 6, 8, 10 and 12 months of age were 21.31 mm, 31.16 mm, 39.53 mm, 46.63 mm, 52.67 mm and 57.79 mm. Total, natural, and fishing mortalities were estimated at 2.39 a−1, 1.32 a−1 and 1.07 a−1. The exploitation level (E) was 0.45. Results of the current study also demonstrated that T. granosa in the Marudu Bay has two major recruitment peaks; one in March and another in October. The exploitation level revealed that natural stock of T. granosa in the Marudu Bay was approaching the maximum exploitation level. If such trend continues or demand for T. granosa is increasing, coupled with no effective fisheries management in place, possibility of the T. granosa population in the Marudu Bay to collapse is likely to elevate.

  5. 5

    المصدر: Ocean Science Journal. 56:156-166

    الوصف: This study on the growth pattern of the blood cockle Tegillarca granosa focused on the aspects of biometric prints on the shell, which aimed to predict the growth of the T. granosa population in the northern region of Malacca Strait. The local sample populations of the cockle were collected in three different intertidal areas called Lhokseumawe and Banda Aceh in Indonesia and Pulau Pinang in Malaysia. The biometric analysis showed that the length–weight relationship model of T. granosa populations in this region indicated that the cockle population generally had a negative allometric growth pattern (b

  6. 6

    المصدر: Repositório Científico de Acesso Aberto de Portugal
    Repositório Científico de Acesso Aberto de Portugal (RCAAP)
    instacron:RCAAP

    الوصف: This study reports the reproductive cycle, condition index, size at first maturity, growth and the morphometric relationships of the common cockle Cerastoderma edule in Ria de Aveiro (NW Portugal), fundamental knowledge in fisheries management planning and ecosystem conservation. The reproductive cycle was monitored for a period of two years, from January 2013 to December 2014. Spawning extended from June to October, with a peak in the summer months (July to September). The condition index showed a seasonal pattern which appear related to food availability and gametogenic cycle. Sexual maturity was attained at a shell length of 18.6 mm during the first year of life, which stands below the minimum landing size currently in force (25 mm). The von Bertalanffy growth equation was based on size-at-age data obtained from the microscopic analysis of growth rings in sectioned shells: Lt = 40.7[1-e −0.74(t-0.30)]. The morphometric relationships between shell dimensions (length, height and width) were studied in order to understand the effects of ontogenetic changes in cockles` shell morphology, an information that is useful to improve the selectivity of the fishing gears and the size-sorting devices. Some management strategies for the Ria de Aveiro cockle fishery were proposed.

  7. 7

    المصدر: Journal Of Sea Research (1385-1101) (Elsevier BV), 2022-01, Vol. 179, P. 102148 (9p.)

    الوصف: A better understanding of growth drivers in shellfish populations including the common cockle Cerastoderma edule is essential, as their future is challenged by unsustainable fishing practices and climate change. In this study the spatial and temporal variabilities in common cockle growth across latitudes were assessed and compared with historical data. Six locations were examined at bimonthly intervals over 19 months; three Irish, two Welsh and one French, spanning the latitudes 54°N to 44°N. The results demonstrated that local abiotic and biotic factors have a larger impact on cockle growth than latitude. Cockles at similar latitudes grew at different rates and sizes, possibly due to factors such as density, fishing activity and interspecific competition. Cockles (0–3 years) impacted by low salinity and parasites (trematodes), exhibited reduced growth in later years. At the warmest, southernmost site growth was lowest in cockles >2 years. Previously, cockles at that site have been shown to spawn almost year-round, possibly diverting energy to gonad development rather than growth. The results opposed previously literature which demonstrated significantly greater growth at lower latitudes. These findings affirm that cockle growth and size is variable due to local abiotic (reduced salinity) and biotic (potentially trematode infection) drivers. Additionally, the synergistic relationship between these factors, i.e. warmer temperatures driving prolonged spawning, and the potential association between lower salinities and trematode prevalence, is concerning due to predicted climate related increases in temperature, precipitation and trematode prevalence/transmission, which may result in northern cockles reaching smaller maximum sizes.

    وصف الملف: application/pdf

  8. 8

    المساهمون: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Bioscience [Aarhus], University of Exeter, Institute of Geosciences [Mainz], Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Institute of Oceanography and Fisheries, European Project: 604802,EC:FP7:PEOPLE,FP7-PEOPLE-2013-ITN,ARAMACC(2013), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Johannes Gutenberg - Universität Mainz (JGU)

    المصدر: Featherstone, A M, Butler, P G, Schöne, B R, Peharda, M & Thébault, J 2020, ' A 45-year sub-annual reconstruction of seawater temperature in the Bay of Brest, France, using the shell oxygen isotope composition of the bivalve Glycymeris glycymeris ', Holocene, vol. 30, no. 1, pp. 3-12 . https://doi.org/10.1177/0959683619865592Test
    Holocene
    Holocene, 2020, 30 (1), pp.3--12. ⟨10.1177/0959683619865592⟩
    Holocene (0959-6836) (SAGE Publications), 2020-01, Vol. 30, N. 1, P. 3-12

    الوصف: A reconstruction of sea surface temperature (SST) spanning 45 years (1966–2011) was developed from δ18O obtained from the aragonitic shells of Glycymeris glycymeris, collected from the Bay of Brest, France. Bivalve sampling was undertaken monthly between 2014 and 2015 using a dredge. In total, 401 live specimens and 243 articulated paired valves from dead specimens were collected, of which 24 individuals were used to reconstruct SST. Temperatures determined using the palaeotemperature equation of Royer et al. compared well with observed SST during the growing season between 1998 and 2010 (Pearson’s correlation: p = 0.002, r = 0.760). Furthermore, a significant negative correlation was found between the reconstructed SST and the North Atlantic Subpolar Gyre (SPG) index ( p = 0.001, r = −0.50), and a significant positive correlation was found with the East Atlantic Pattern (EAP) index when the reconstructed SST was lagged by 1 year ( p = 0.002, r = 0.46). This led to the conclusion that EAP and SPG are major influences on SSTs in the Bay of Brest. As the SPG controls air temperature in Northern Europe and the EAP controls water temperature in Southern Europe, this suggests that the Bay of Brest is an interaction area between these two climate systems. As such, this locality is interesting as the δ18O of the shells can be used as a proxy for both the SPG and EAP, and temperature reconstructions can provide a unique insight into how these climate systems interacted prior to the instrumental era.

    وصف الملف: application/pdf

  9. 9
  10. 10

    المصدر: Ilmu Kelautan, Vol 24, Iss 4, Pp 171-178 (2019)

    الوصف: Blood cockle Anadara granosa is a popular sea food in Indonesia and potential for aquaculture. Currently, blood cockle aquaculture is at early stage, done by taking the larva from wild and raised them in the pond. Wild animal naturally carries parasites without outward clinical signs but can cause disease problem under aquaculture condition. This study aimed to identify parasites and histopathology changes in wild A. granosa. Blood cockles (n=90) were randomly collected during 3 months at three stations in the coastal waters of Bedono (Station 1: the intertidal area of the edge near to the mangrove area, station 2: the center of intertidal area, station 3: the area near to the sea), a village located on North Java coast and supplied blood cockle larva to the area. Parasites examination was conducted in the laboratory by macroscopic (observation of clinical symptoms) for ectoparasites and microscopic (using a microscope) for endoparasites. Histopathology preparation was done by taking three cockles at each station and cutting tissue that includes gills, foot, gonads, digestive tract and mantle. Organs were fixed in a 10% NBF solution, processed, mounted in paraffin and stained with hematoxylin and eosin. Parasites found were identified and the level of intensity and prevalence were calculated. There were three species of parasites found: Pinnotheres sp. (Intensity 1 ind/cockle; Prevalence: 3.33%), Perkinsus sp. (Intensity: 9.3 cell/cockle; Prevalence: 37.03%), Nematopsis sp. (Intensity: 4.25 cell/cockle; Prevalence: 29.62%). There were no histopathology changes on infected tissues which may relate to low diversity, prevalence and intensity of parasites found in this study.