Comparison of the size selectivity of diamond (PA) and square (PE) mesh codends for deepwater crustacean species in the Antalya Bay, eastern Mediterranean

The aim of this study was to compare selectivity results of currently used 44 mm nominal polyamide (PA) diamond mesh- and alternatively suggested 40 mm nominal polyethylene (PE) square mesh- codends in the deepwater crustacean trawl fishery in the Antalya Bay, eastern Mediterranean. Selectivity experiments were carried out during targeted trawling of four commonly harvested crustacean species: giant red shrimp Aristaeomorpha foliacea , 'blue and red' shrimp Aristeus antennatus , rose shrimp Parapenaeus longirostris , and pandalid shrimp Plesionika martia . A conventional bottom trawl of 600 meshes around the fishing circle was operated onboard a commercial stern trawler between 6 and 18 June 2007. Depth of the fishing area varied between 441 and 630 m. Data were collected using the covered codend technique, and analyzed using a logistic equation with maximum likelihood for individual and pooled hauls. The commercially used trawl codend was unable to release immature crustaceans. Selectivity parameters of the three species of crustaceans were distinctly lower when collected with the polyamide diamond mesh than with the polyethylene square mesh, except in the case of giant red shrimp for which values were similar. However, the present and previous results show that in square mesh codends, mesh sizes must be more than 40 mm in order to keep catches clear of specimens below minimum landing sizes or 50% sexual maturity sizes of crustaceans in the Mediterranean. This study suggests that regulating mesh size by requiring square mesh openings during deep water crustacean trawling of the eastern Mediterranean is essential for the release of immature individuals.     

Selectivity of diamond (PA) and square (PE) mesh codends for commercially important fish species in the Antalya Bay,eastern Mediterranean

Size selectivity of the 40 mm nominal polyethylene (PE) square mesh codend and the 44 mm nominal polyamide (PA) diamond mesh codend were determined under commercial conditions in the demersal trawl fishery. Data were collected using the covered codend technique and analyzed by logistic equation with a maximum likelihood method. Changing the mesh from a 44 mm PA diamond to a 40 mm PE square increased the mean retention lengths (L₅₀s) of red mullet (Mullus barbatus), picarel (Spicara maena) and bogue (Boops boops) and decreased the selection ranges (SR) for common pandora (Pagellus erythrinus). For large‐eye dentex (Dentex macrophthalmus) and axillary sea bream (Pagellus acarne) mean L₅₀ and SR values were 9.6 and 11.8, and 2.4 and 2.4 cm, respectively, only in the DM44PA codend. For golden banded goatfish (Upeneus moluccensis) values for SM40PE were only 15.0 and 2.7 cm, respectively. Results showed that the 40 mm PE square mesh codend provided higher selectivity for most of the Mediterranean fishes. The results also showed that regulating mesh size and requiring square mesh openings during trawling is essential for the release of immature individuals. This practice will result in a reduction in overfishing and permit recovery of overfished stocks.     

Influence of the cymothoid isopods Meinertia oestroides, Meinertia parallela, and Anilocra physodes (Crustacea; parasites of fish) on the growth of hosts, Boops boops and Pagellus erythrinus (Sparidae) (author's transl)]

Studies of weight-size (W = aLb) and growth (L = aT + b) in fish (Boops boops and Pagellus erythrinus), potential hosts of some Cymothoid isopods (Meinertia oestroides, Meinertia parallela, and Anilocra physodes) have been performed. Infested fishes show a slight decrease in weight compared to normal fish. Cymothoid do not exert a significant influence on the weight-size ratio; on the other hand, a delay in growth does occur.     

Size selectivity of three diamond mesh codends for the European hake (Merluccius merluccius) and the tub gurnard (Trigla lucerna) in the Sea of Marmara, Turkey

The effects of an increase in the codend mesh size from 44 to 56 and 80 mm on size selectivity of the two by‐catch species (the European hake Merluccius merlucius and the tub gurnard Trigla lucerna) commonly captured in the shrimp fishery in the Sea of Marmara, were evaluated. The parameters of the logistic selectivity model were estimated by maximum likelihood. Length at 50% retention, L₅₀, was found to increase with mesh size for both species. The L₅₀ values of 44, 56 and 80 mm were, respectively, 19.8, 21.5 and 33.4 cm for European hake, 17.9, 17.7 and 25.6 cm for tub gurnard. The main conclusions are that 44 mm and 56 mm diamond mesh codends retain a considerable amount of undersized hake and tub gurnard as by‐catch in the shrimp fishery. With 80 mm mesh size codend, most juvenile European hake are released. For the tub gurnard, however, even this mesh size does not provide a good enough selection. From the biological point of view, it is concluded that the legal 44 mm diamond mesh codend does not provide satisfactory selection for European hake and the tub‐gurnard in trawl fisheries of the Sea of Marmara.     

Floral and vegetative morphometrics of five Pleurothallis (Orchidaceae) species: correlation with taxonomy,phylogeny, genetic variability and pollination systems

Morphometric analyses of vegetative and floral characters were conducted in 21 populations of five Pleurothallis (Orchidaceae) species occurring in Brazilian 'campo rupestre' vegetation. A phylogenetic analysis of this species group was also carried out using nuclear ribosomal DNA internal transcribed spacers (ITS1 and ITS2). Results of the ordination and cluster analyses agree with species' delimitation revealed by taxonomic and allozyme studies. The groups formed in ordination analysis correspond to the pollinator groups determined in a previous pollination study. Relationships among the species in the cluster analysis using only vegetative characters are similar to those found in a previous allozyme study, but those indicated by cluster analysis using only floral characters differ. These results support the hypothesis that floral similarities are due to convergence driven by similar pollination mechanisms, and therefore floral traits may not be good indicators of phylogenetic relationships in this group. The results of the phylogenetic analysis support this conclusion to some extent. There is no correlation between genetic (allozyme) and morphological variability in the populations nor in the way this variability is distributed among conspecific populations. We describe a new subspecies of Pleurothallis ochreata based on differences in vegetative and chemical characters as well as geographic distribution. Absence of differentiation in floral characters, attraction of the same pollinator species, interfertility and genetic similarity support the argument for subspecific rather than specific status.     

Functional response of Macrolophus pygmaeus (Rambur) and Nesidiocoris tenuis (Reuter) feeding on two different prey species

Functional response type and predatory parameters of Macrolophus pygmaeus and Nesidiocoris tenuis (Hemiptera: Miridae), the two important predators widely used in IPM programmes at tomato greenhouses, were investigated. The predators fed on Tuta absoluta (Lepidoptera: Gelechiidae) or Ephestia kuehniella (Lepidoptera: Pyralidae) eggs. Different densities of prey eggs including 1, 2, 3, 4, 5, 8, 10, 15, 20, 30 and 40 (latest only for E. kuehniella) were used at laboratory conditions. The results showed that both predatory bugs had type II functional response. Also, predation indices were significantly different between the predators. Although N. tenuis was more efficient against T. absoluta eggs than M. pygmaeus, M. pygmaeus predatory indices showed that this predator was more efficient on E. kuehniella eggs. Thus, minimum and maximum attack rate were observed in N. tenuis fed on E. kuehniella (0.0871 h^?1) and T. absoluta (0.2514 h^?1) eggs, respectively. Whilst, the minimum and maximum handling time were observed in M. pygmaeus fed on E. kuehniella (1.8695 h) and T. absoluta (2.7415 h) eggs, respectively.     

An analysis of two Myosorex species (Soricidae) from the Early Pliocene site of Langebaanweg (West coast, South Africa) using geometric morphometrics, linear measurements, and non-metric characters

This represents the first study of the soricid community from the Early Pliocene site of Langebaanweg (LBW) which is represented by four species, two of which belong to the soricid genus Myosorex (Forest shrew). Using geometric morphometrics the two Myosorex fossil species are compared with each other, and the extant western and eastern Cape species: Myosorex varius, M. cafer and M. longicaudatus. In addition, the results from an analysis of a number of non-metric characters and linear measurements on the fossil species are presented. The mandibles of the fossil species are characterized by extremely broad teeth, ascending rami which are relatively gracile and differ in shape and size from modern species, and the existence of a number of primitive features of the mandibles and teeth. This evidence is interpreted as indicating that the two LBW Myosorex species represent an archaic lineage now extinct in southern Africa.     

Palaearctic species of the genus Confluaria Ablasov (Cestoda,Hymenolepididae): redescriptions of C. multistriata (Rudolphi, 1810) and C. japonica (Yamaguti, 1935), and a description of Confluaria sp.

Confluaria multistriata (Rudolphi, 1810) is redescribed on the basis of specimens from Tachybaptus ruficollis from the material of Rudolphi and Dollfus and new specimens from the same host species from Bulgaria. The types of C. japonica (Yamaguti, 1935) from T. ruficollis are also redescribed and figured. A single specimen from the collection of Krabbe, described as Taenia multistriata, is re-examined and recognised as belonging to a different species of Confluaria, the status of which remains to be established. Criteria for distinguishing the three species are proposed. In view of the present results, some of the previous records of C. multistriata and C. japonica are re-evaluated. The synonymy of the genera Colymbilepis Spasskaya, 1966 and Confluaria Ablasov in Spasskaya, 1966 is confirmed.     

Notes on Metaphire multitheca (Chen, 1938) (Oligochaeta,Megascolecidae) recorded from Vietnam,with descriptions of two new species

The paper deals with Pheretima multitheca multitheca Chen, 1938 recorded from Vietnam (non Pheretima multitheca Chen, 1938 now in Metaphire from Hainan Island). As a result, a new species, Amynthas erroneous sp. n., is revealed from materials which were previously misidentified as Pheretima multitheca multitheca. The new species is obviously distinguished from other Amynthas species by multiple spermathecal pores lateroventral in intersegments 5/6/7/8/9, and presence of two pairs of crescentic genital markings in xviii. In addition, another new species, Amynthas nhonmontis sp. n., is described and easily recognized by multiple spermathecal pores ventral in intersegments 5/6/7/8 and three pairs of genital markings in xvii, xix and xx.     

Further studies on water mites from Korea,with description of two new species (Acari,Hydrachnidia)

New records of water mites (Acari: Hydrachnidia) from streams in South Korea are presented. Two species are described as new to science: Torrenticola neodentifera sp. n. (Torrenticolidae) and Atractides ermilovi sp. n. (Hygrobatidae). Five species are reported as first records for Korea: Wandesia (Wandesia) reducta Tuzovskij, 1987, Wandesia (Wandesia) cf. rara Tuzovskij, 1990, Sperchon (Sperchon) orientalis Tuzovskij, 1990, Feltria (Feltria) kuluensis Tuzovskij, 1988 and Atractides (Atractides) constrictus (Sokolow, 1934). The latter species is redescribed and elevated to species rank based on new material from the Russian Far East.     

Three species of Heilipodus (Coleoptera,Curculionidae) with different karyotypes and sex chromosome systems

This work includes the cytological studies of three species of Heilipodus (Coleoptera, Curculionidae, Molytinae, Hylobiini) that live on plants of the genus Eryngium (Umbelliferae). The three have the same chromosome number (2n=30), but differ in the morphology of their autosomes and in their sex chromosomes.All specimens of Heilipodus erythropus (Klug) showed a typical parachute-like sex bivalent, some individuals of Heilipodus sp. possessed either a simple Xy_p or a sex multivalent involving a telocentric autosomal pair and the parachute bivalent. Finally, Heilipodus scabripennis (Klug) has multiple sex chromosomes neoX_pneoX-neoYy_p.     

Microsatellite loci for two East African tree species, Leptonychia usambarensis (Sterculiaceae) and Sorindeia madagascariensis (Anacardiaceae)

We isolated 20 trinucleotide microsatellites from two African tree species: Sorindeia madagascariensis (nine microsatellites) and Leptonychia usambarensis (11 microsatellites). Number of alleles ranged from three to seven in Sorindeia and two to 10 in Leptonychia. Observed heterozygosity ranged from 0.025 to 0.829 for Sorindeia and from 0.226 to 0.933 for Leptonychia. Two loci from each species departed from Hardy-Weinberg equilibrium. These microsatellite markers will be used to study how forest fragmentation affects pollination and seed dispersal processes of these tree species.     

Melatonin effects on food intake and activity rhythms in two fish species with different activity patterns: Diurnal (goldfish) and nocturnal (tench)

Melatonin has several known physiological functions, the main one being synchronization of daily and seasonal rhythms. In addition, melatonin has been reported to influence food intake and behavioral rhythms with varying results depending on the species. The aim of this research was to evaluate the effects of intraperitoneal melatonin injection on food intake and locomotor activity in two different fish species: goldfish (diurnal) and tench (nocturnal), under different light regimes: constant light (LL) conditions or LD 12:12, with melatonin administration at mid-light (ML), mid-dark (MD), and after a 1-h light pulse at MD. In addition to these acute tests, in the case of goldfish we also investigated the effects of daily melatonin administration for 1 week. Our results indicated that acute melatonin administration significantly decreased goldfish food intake (16-52% inhibition, depending on the light regime) and locomotor activity (55-100%), with the chronic treatment inducing a similar total food intake inhibition that persisted for 7 days. In tench, a nocturnal fish species, acute melatonin administration at MD and ML reduced food intake (37% and 29%, respectively), while locomotor activity was not affected at MD and slightly increased at ML. Taken together, these results indicated that melatonin reduced food intake in both species, while its effects on locomotor activity depended on the time of administration (light or dark phase) and the activity patterns of the species.     

Observations on two closely related species, Chaetoceros tetrastichon and C. dadayi (Bacillariophyceae)

Two tropical-subtropical species of the diatom genus Chaetoceros, C. tetrastichon and C. dadayi were studied in light, scanning and transmission electron microscopy, from plankton samples collected in the Gulf of California, off the coasts of Baja California and the Mediterranean Sea. Both species are usually found to be attached to a tintinnid. The basic structure of both species agrees with previous studies of species belonging to the subgenus Phaeoceros , including the finely perforated cell wall of the valves and the presence of one rimoportula in every valve of the cells in the chain, which is located in the centre of the annulus. A clear costae pattern was found in C. tetrastichon , but it is less apparent in C. dadayi. Other differences between the two species are the direction and morphology of the setae, especially the anterior terminal ones, and the number of girdle bands. Questions on the function of the setae in Chaetoceros continue offering matter for speculation.