Assessment of Anthropogenically Stressed Ecosystem of Port Waters Using Macrobenthic Community-Biotic Indices

Macrobenthic community being used as marine health indictor vis-à-vis to anthropogenic disturbance since their characteristic of life cycle (reproductive mode, sedentary, energy transfer, sensitive-resistance species, indicator organism etc.). Therefore, the present study was chosen in Vizag port waters have been subject to a variety of anthropogenic pressure in the last two decades. The purpose of this study was to assess the ecological status of the port environment through biotic indices like AZTI 's Marine Biotic Index (AMBI) and Multivariate-AMBI Index (M-AMBI) which have been successfully validated geographically and anthropogenically stressed habitats. The result revealed that the inner harbor (IHC, Iron ore Q1 & Iron ore Q7) stations are heavily disturbed while the outer harbor fall between undisturbed and moderately disturbed status. It was observed that the reduced tidal action inside the harbor determines the health status indicating that the Iron ore transporting areas are at high risk with respect to benthic population.

DIVERSITY AND POPULATION STRUCTURE OF MACROINVERTEBRATES IN THE GLACIER FED STREAM BALKHILA AT TILFARA FROM GARHWAL HIMALAYA

This paper deals with the study of macrozoobenthic community in the glacier fed stream Balkhila which is an important tributary of Alaknanda River. In this study it was found that the maximum macrozoobenthos were recorded in the month of February (387.5±106.5 units/m2 ) followed by January (382.2±144.7 units/m2 ) whereas, minimum in July (21.6±15.3 units/m2 ) and August (21.6±0.0 units/m2 ). The stream is represented by 15 genera belonging to 6 orders viz. Ephemeroptera (Baetis, Cinygmula, Caenis, and Heptagenia), Trichoptera (Glossosoma, Rhyachophila, Agapetus, Hydropsyche, Chimarra and Stenopsyche), Diptera (Antocha and Chironomus), Coleoptera (Psephenus), Odonata (Euphaea) and Plecoptera (Perla). The regression analysis and the correlation coefficient were used to show the relationship between macrozoobenthos and various physico-chemical parameters. The Shannon-Wiener diversity index was calculated to study the benthic diversity of the stream. In order to depict the homogeneity among different benthic orders, the multivariate cluster analysis was used. The Canonical correspondence analysis (CCA) was used to investigate the seasonal effect of detrimental ecological factors on benthic population.

Cretaceous cultch: substrate availability for oyster Exogyra in the Maastrichtian of the eastern Mississippi Embayment

The gryphaeid oyster Exogyra Say, 1820, is ubiquitous in Upper Cretaceous sediments in the southeastern United States. Like many oysters (Order Ostreida), Exogyra attached its shell to hard surfaces on the seafloor by means of cementation. Throughout its lifetime, Exogyra may preserve through bioimmuration the characteristics and even skeletal remains of substrate organisms, including mollusk shells, echinoids, and bryozoans. Exogyra costata of all sizes were collected from three different localities within upper Maastrichtian deposits in northeast Mississippi and their bioimmurations analyzed. Substrates were identified and classified to compare the three localities’ substrate taxa in order to probe differences in benthic population structure. The results of this pilot study provide an overview of available surfaces on the Late Cretaceous seafloor on the eastern side of the Mississippi Embayment. The data suggest that taxonomic diversity among utilized substrates may increase from north to south, which corresponds to increasing depth from shallow marine to deeper sediments on the shelf.

Biotypology of stream macroinvertebrates from North African and semi arid catchment: Oued Za (Morocco)

The aim of this study is to investigate the longitudinal zonation of macroinvertebrates assemblages in the Za River basin, the main tributary of Moulouya River (Morocco). This work carried out in three campaigns between March and August 2014 on 12 stations selected. This study allowed the identification of 137 species classified in 109 genera and 65 families. In addition to the physicochemical parameters measured three times in each station, a description of the aquatic environment was made to characterize each of the stations surveyed; in particular with regard to altitude, slope, Emberger quotient, thermal amplitude, kilometers at the source, current velocity and bioclimatic zones. The treatment of this benthic population as well as the stations environmental descriptors, using Foucart' factorial correspondence analysis (FCA) and partial triadic analysis (PTA) respectively, allowed for the development of a typology of this watercourse, where altitude and current speed seem to play a major role in the distribution of benthic invertebrates. The biocenotic study revealed the presence of three stationary groupings corresponding to four faunal groups.

Phenotypic plasticity of the threespine stickleback Gasterosteus aculeatus telencephalon in response to experience in captivity

Threespine stickleback were used to examine phenotypic plasticity of telencephala in relation to inferred ecology. Fish from derived, allopatric, freshwater populations were sampled from three shallow, structurally complex lakes with ben-thic-foraging stickleback (benthics) and from three deep, structurally simple lakes with planktivores (limnetics). The telencepha-lon of specimens preserved immediately after capture (field-preserved), field-caught fish held in aquaria for 90 days (lab-held), and lab-bred fish from crosses and raised in aquaria were compared. Field-preserved sea-run (ancestral) stickleback were collected from two separate sites, and parents of lab-bred sea-run stickleback were collected from one of these sites. In field-preserved and lab-held fish, the telencephala of limnetics exhibited triangular dorsal shape, while those of benthics and sea-run fish had rounder shapes. No such pattern was detected in lab-bred fish. Within each treatment type, benthics had larger relative telencephalon sizes, using overall brain size as the covariate, than limnetics. Among field-preserved samples, sea-run fish had smaller telencephalon sizes than lake fish. Intra-population analyses of lake samples showed that field-preserved fish consistently had larger relative telencephalon sizes than lab-bred fish. The opposite was true of the sea-run population. In a separate study using one benthic population and one limnetic population, samples were preserved in the field immediately or held in the lab for 30, 60, and 90 days before they were sacrificed. In both populations, the telencephalon shapes of lab-held fish were similar to those of field-preserved fish but became progressively more like lab-bred ones over 90 days. In contrast, relative telencephalon size decreased dramatically by 30 days after which there was little change. In freshwater threespine stickleback, the telencephalon exhibits considerable phenotypic plasticity, which was probably present in the ancestor.

Neustonic postlarval American lobsters, Homarus americanus, in the western Gulf of Maine: spatial and interannual variations

We examined the seasonal abundance of postlarval (PL) (stage IV) American lobsters, Homarus americanus, from neuston samples from 1989 to 1995 at Johns Bay, Maine, and Seabrook, New Hampshire, located 150 km apart in the western Gulf of Maine. The postlarval season at these sites began between approximately days of the year 180 and 210 and ranged from about 35 to 70 days in duration. Within years, start and end dates were similar for the two sites. Maximum concentrations from single tows exceeded 100 PL·1000 m-2, but 85% or more of the positive tows had concentrations <15 PL·1000 m-2 and more than half had <5 PL·1000 m-2. These concentrations occurred at high levels of the stock, were the source for continued high recruitment in the 1990s, and thereby form a benchmark for future measurements. Only one of the seven years showed a major decline in seasonal abundance, and it occurred at both sites. Of the remaining years, three had nearly identical integrated abundances at both sites (approximately 200 PL· 1000 m-2·year-1). A survey in the western Gulf of Maine caught postlarvae out to 56 km offshore at concentrations similar to the coastal samples, indicating a broadly distributed source of potential recruits to the benthic population.