Intraspecific variation of isozymes in Arenicola marina (Polychaeta: Annelida)

Six enzyme systems, namely acid phosphatase, leucine aminopeptidase, phosphoglucose isomerase, tetrazolium oxidase, esterases and malate dehydrogenase were studied electrophoretically in Arenicola marina from various localities in United Kingdom. Out of 13 presumed loci, ten were found monomorphic. The three loci which appeared to be polymorphic are LAP-1, EST-2 and TO-1. Due to small sample size allele frequencies and genetic identity were not calculated. However, results indicate genetic difference among the population of A. marina.

Diversity, abundance distribution and secondary production of intertidal and subtidal benthic macrofauna of Bushehr Province with emphasis on annelida groups

The present investigation was undertaken to establish a reference situation for future use, to identify temporal and spatial composition of macrofauna and estimate some ecological indices in the sub tidal waters along the Bushehr coastal waters in Persian Gulf. Six transects were selected including Genaveh, Farakeh, Shif, Bandargah, Rostami and Asalouyeh, at each transect 3 station were sampled in depths of zero, 5 and 10 metres. Sampling was seasonally carried out by a VAN VEEN grab 0.0225 m2, during summer 2008 until spring 2009. Samples were wet sieved immediately using 0.5 mm mesh size sieves and sediment retained in the sieve was preserved in 4% buffered formalin solution. Macrofauna specimen were separated from the sediments using decantation and elutriation methods, enumerated and identified up to the Genus level. Environmental factors such as temperature. pH, and salinity were recorded in field using sensitive probs and refractometer (for salinity) and also sediment samples were taken for TOM and grain size analysis in all the stations. 5611 specimens belonging to 66 genera were collected during the present study. Polychaetes were dominant both in terms of genus number (31) and relative abundance (74 % of total macrofaunal abundance). The other dominant groups were Artheropoda, (16.1%), Molusca (2.8%), Echinodermata (1.29%) and others including Nematoda, Nemertina, Echiura and Turbellaria (5.8%). Thirty one Genera belong of 27 families of polychaeta, one genus and family of Subphylum Chlicerata,19 genera belong to 14 families of Crustacea, 8 genera belong to 6 families of Molusca, were indentified in the studied region. 1 family (Polygordidae) and 3 genera (Flabeligera, Pilargis and Polygordius) of Polychaeta, 1 family (Nymphonidae) and genus (Nymphon) of Chelicerata, 1 Family (Nematoplanidae) and genus (Nematoplana) of Turbellaria, were identified for the first time in Persian Gulf area. The result indicated that macrofauna organism have strong relationship with the grain size characteristics of the sediments they inhabit. The most surface deposit feeder specimens such as Prionospio and Cossura were found in zero meters depth of Genaveh, Farakeh, Bandargah, Rostami and Asalouyeh stations with sandy substratum, however the most burrowing deposit feeder and scavenger specimens such as Capitella and Petaloproctus were collected in 5 and 10 meter depths of stations with silty–clay substratum. The annual mean abundance, Shanon- weiner diversity and evenness of macrofauna were estimated1152.73 N/ m² , 2.72 and 0.792 respectively .The annual average biomass and secondary production were computed 1.797 gDW m² and 3.594 gDW m² y-1 .The average of water temperature, salinity, pH and oxygen concentration were recorded between 16.37-36.05 °C, 38-42 g/l, 7.89-8.76 and 4.23-8.23 mg/l, respectively during this study in 6 studied region. Among of investigated stations Asalouyeh adjacent of effluent canal of Gas and petrochemical industry sewage and Farakeh regions adjacent the Helleh estuary had the lowets and the highest community indices. The average of diversity and density in 5 meters depth stations with moderate of sand, silt and clay were slightly more than 2 other depths stations, it seems that 5 meters stations are made a transition habitats between 2 sandy and clay habitats, that can be used by 2 groups of surface and borrowing deposit feeders. Based on the data provided in this survey, the temperature variation, sediment texture, TOM, type habitat and manmade factors of Gas and petrochemical industries have had the most effect on the macrofauna community structure in the studied region during sampling periods.

Quantitative composition and distribution of the macrobenthic invertebrate fauna of the Continental Shelf ecosystems of the Northeastern United States

From the mid-1950's to the mid-1960's a series of quantitative surveys of the macrobenthic invertebrate fauna were conducted in the offshore New England region (Maine to Long Island, New York). The surveys were designed to 1) obtain measures of macrobenthic standing crop expressed in terms of density and biomass; 2) determine the taxonomic composition of the fauna (ca. 567 species); 3) map the general features of macrobenthic distribution; and 4) evaluate the fauna's relationships to water depth, bottom type, temperature range, and sediment organic carbon content. A total of 1,076 samples, ranging from 3 to 3,974 m in depth, were obtained and analyzed. The aggregate macrobenthic fauna consists of 44 major taxonomic groups (phyla, classes, orders). A striking fact is that only five of those groups (belonging to four phyla) account for over 80% of both total biomass and number of individuals of the macrobenthos. The five dominant groups are Bivalvia, Annelida, Amphipoda, Echninoidea, and Holothuroidea. Other salient features pertaining to the macrobenthos of the region are the following: substantial differences in quantity exist among different geographic subareas within the region, but with a general trend that both density and biomass increase from northeast to southwest; both density and biomass decrease with increasing depth; the composition of the bottom sediments significantly influences both the kind and quantity of macrobenthic invertebrates, the largest quantities of both measures of abundance occurring in the coarser grained sediments and diminishing with decreasing particle size; areas with marked seasonal changes in water temperature support an abundant and diverse fauna, whereas a uniform temperature regime is associated with a sparse, less diverse fauna; and no detectable trends are evident in the quantitative composition of the macrobenthos in relation to sediment organic carbon content. (PDF file contains 246 pages.)

Seasonal variation in the occurrence of some zooplankton in a fish pond

Observations were made on the seasonal variation in the occurrence of some zooplankton in a fish pond. A total of 31 genera were recorded, out of these, 8 belongs to Rotifera, 5 to Copepoda, 112 to Cladocera, 3 to Protozoa, 2 to Nematoda and 1 to Oligochaeta. The role of temperature, dissolved oxygen, free Co2, pH, turbidity and alkalinity in the occurrence of different genera is discussed.

A Guide to the freshwater fauna of Ceylon. Supplement 2

This is the second supplement to "A guide to the freshwater fauna of Ceylon" by A. S. Mendis and C. H. Fernando, Bull. Fish. Res. Stn., Ceylon, No. 12, 160 pp. (1962). In the present supplement additions and corrections are made in the sections on Protozoa, Annelida and Arthropoda. The sections on Platyhelrainthes and Nematoda have been expanded and the Acanthocephala added. A list of species recorded and the hosts of the parasitic forms are included. In the "Guide", the insects with only larval stages in aquatic habitats were mentioned only briefly and no species lists were included. In this supplement this gap is largely filled by added notes and inclusion of species lists of all these groups except the Neuroptera, Lepidoptera, Tabanidae, Syrphidae and Stratiomyidae. The orders Neuroptera and Lepidoptera have relatively few members in freshwater habitats and the families Tabanidae, Syrphidae and Stratiomyidae have forms with larvae in aquatic habitats and also in moist places which are not true freshwater habitats. At this time, it is not possible to separate those forms living in freshwater habitats. Short diagnoses of six additional families are given, namely, the ixidae, Psychodidae, Tabanidae Stratiomyidae, Rhagionidae and Sciomyzidae. Keys are provided for the Odonata and Ephermeroptera larvae down to the family level. An attempt has been made to make the references more comprehensive. Works dealing specifically with the Ceylonese fauna are of course included, but in addition those which are of use in diagnosis of local genera and species have been cited.

Benthic community survey of Gwadar (east bay) Balochistan, Pakistan

Benthic communities of the Gwadar east bay (Balochistan) was surveyed during the onset of S.W. monsoon. A total 1030 specimens were collected which represented Phyla of Arthropoda, Mollusca, Annelida, Echinodermata. The most abundant class observed was that of Bivalvia. Seawater parameters such as dissolved oxygen, temperature, pH, salinity together with sediment characteristics were measured. Analysis of variance between observed stations and fauna do not show any significant difference (P<0.05). The present observation forms a baseline study in the area.

Survey of parasitic infection of Sander lucioperca (Linnaeus, 1758) and Silurus glanis (Linnaeus, 1758) in Aras reservoir with emphasizes of monogenean parasites

The parasites fauna of 491 specimens of Sander lucioperca, Linnaeus 1758 (246 specimens) and catfish, Silurus glanis, Linnaeus 1758 (245 specimens) in different size from Aras Reservoir situated in North —west of the Iran was investigated. During 2006-2007 Totally 16 parasite species were recorded. The most various parasites was found in catfish (10 species) while the lowest number was recorded in Sander lucioperca (6 species). Among them, however three genera of protozoa (Trichodina, Vorticella, Ichthyophthirius), two genera of Monogenea (Gyrodactylus, Silurodiscoides), Digenea, Cestoda, Nematoda, Acanthocephala and Annelida one species each (Diplostomum, Protocephalus, Eustrongylides, Neoechinorhynchus, Pisicola) and two crustacean genera (Argulus and Lernea) recorded and we can come to conclusion in comparison with the earlier data the actual parasite fauna of two hosts has been greatly improved. According to the present study the prevalence, mean abundance and mean intensity of parasites species of both hosts were highly influenced by seasons of the year. Some species found, however show a tendency to be more abundant ides Trichodina sp., Ichthyophthirius multifiliis, Silurodiscoides vistolensis, Protocephalus osculatus respectively. Most parasites species live in gills and skin, where is highly sensitive to some pathogens parasites species (Trichodina, Vorticella, Ichthyophthirius, Pisicola geometra, Argulus foliaceus; Lernea) and While some are specialist (Silurodiscoides vistolensis and Silurodiscoides siluri) other more or less generalist (ichthyophthirius).