Physiological Determinants of Invasive Success Linking Distribution Patterns to Metabolic Physiology in Native and Invasive Blue Mussels (genus Mytilus)

In the early 20th century, a blue mussel species from the Mediterranean invaded the California coast and subsequently out-competed the native species south of Monterey Bay. Like other invasive species, Mytilus galloprovincialis has physiological traits that make it successful in habitats formerly occupied by the native M. trossulus, namely its adaptation to warm sea surface temperatures. This study looks at the current genotype distributions and enzymatic activities of field-acclimatized mussels within the hybrid zone where the species co-occur as well as mussels that have been acclimated for four weeks to different temperature and salinity conditions. In the field-acclimatized and laboratory-acclimated mussels, the native species exhibited significantly higher enzyme rates, which may reflect an evolutionary adaptation to compensate to low habitat temperatures. Indeed, the results of the laboratory acclimation indicate that these differences are genetically based. Whether an acclimation capacity exists may require even longer-term acclimation to different temperatures. Current findings suggest that the further spread of the invasive species is likely to be governed in large measure by the potentially counteracting effects of rising temperatures, which would favor the northerly spread of M. galloprovincialis, and increased winter precipitation, which would favor the persistence of M. trossulus. However, the success of M. galloprovincialis during acclimation to ‘dilute’ salinity (25 ppt) suggests that the invasive species can tolerate a greater salinity range than previously thought. Thus, further investigation is needed to build a comprehensive predictive model of the movement of M. galloprovincialis and the hybrid zone along the California coast.

Distribution, movements, and habitat use of small striped bass (Morone saxatilis) across multiple spatial scales

Distribution, movements, and habitat use of small (<46 cm, juveniles and individuals of unknown maturity) striped bass (Morone saxatilis) were investigated with multiple techniques and at multiple spatial scales (surveys and tag-recapture in the estuary and ocean, and telemetry in the estuary) over multiple years to determine the frequency and duration of use of non-natal estuaries. These unique comparisons suggest, at least in New Jersey, that smaller individuals (<20 cm) may disperse from natal estuaries and arrive in non-natal estuaries early in life and take up residence for several years. During this period of estuarine residence, individuals spend all seasons primarily in the low salinity portions of the estuary. At larger sizes, they then leave these non-natal estuaries to begin coastal migrations with those individuals from nurseries in natal estuaries. These composite observations of frequency and duration of habitat use indicate that non-natal estuaries may provide important habitat for a portion of the striped bass population.

Spatial and temporal distribution of grouper larvae (Serranidae: Epinephelinae: Epinephelini) in the Gulf of Mexico and Straits of Florida

Little is known about the seasonality and distribution of grouper larvae (Serranidae: Epinephelini) in the Gulf of Mexico and Atlantic Ocean off the coast of the southeast United States. Grouper larvae were collected from a transect across the Straits of Florida in 2003 and 2004 and during the Southeast Area Monitoring and Assessment Program spring and fall surveys from 1982 through 2005. Analysis of these larval data provided information on location and timing of spawning, larval distribution patterns, and interannual occurrence for a group of species not easily studied as adults. Our analyses indicated that shelf-edge habitat is important for spawning of many species of grouper—some species for which data were not previously available. Spawning for some species may occur year-round, but two peak seasons are evident: late winter and late summer through early fall. Interannual variability in the use of three important subregions by species or groups of species was partially explained by environmental factors (surface temperature, surface salinity, and water depth). A shift in species dominance over the last three decades from spring-spawned species (most of the commercial species) to fall-spawned species also was documented. The results of these analyses expand our understanding of the basic distribution and spawning patterns of northwest Atlantic grouper species and indicate a need for further examination of the changing population structure of individual species and species dominance in the region.

Distribution patterns of tidepool fishes on a tropical flat reef

Rockpools on a tropical f lat reef off the southeastern coast of Brazil were sampled to determine the influence of pool morphometry and water characteristics on fish community structure. The pool closest to the inner fringe of the reef had lower salinity and higher temperature due to inflow of groundwater. The other pools varied only with respect to their morphometric characteristics, algal cover, and bottom composition. Species with a strong affinity for estuarine- like waters characterized the pool closest to the beach and distinguished its fish community from that of the other pools. Instead of being strongly structured by the physicochemical setting and position in the reef, fish communities of the other pools were determined by behavioral preferences and intra- and interspecific interactions. Differences in community structure were related to pool size (the larger sizes permitting the permanency of schooling species), to algal cover (which allowed camouflage for large predatory species), to bottom composition (which provided substrate for turf flora available to territorial herbivores), and to ecological effects (e.g., competition, territoriality, and predation). Although distribution patterns of tidepool fishes have previously been related to the availability of niches, independent of pool position in the reef, our results show synergistic interactions between water properties, presence or absence of niches, and ecological relationships in structuring tidepool fish communities.

Multiscale analysis of factors that affect the distribution of sharks throughout the northern Gulf of Mexico

Identification of the spatial scale at which marine communities are organized is critical to proper management, yet this is particularly difficult to determine for highly migratory species like sharks. We used shark catch data collected during 2006–09 from fishery-independent bottom-longline surveys, as well as biotic and abiotic explanatory data to identify the factors that affect the distribution of coastal sharks at 2 spatial scales in the northern Gulf of Mexico. Centered principal component analyses (PCAs) were used to visualize the patterns that characterize shark distributions at small (Alabama and Mississippi coast) and large (northern Gulf of Mexico) spatial scales. Environmental data on temperature, salinity, dissolved oxygen (DO), depth, fish and crustacean biomass, and chlorophyll-a (chl-a) concentration were analyzed with normed PCAs at both spatial scales. The relationships between values of shark catch per unit of effort (CPUE) and environmental factors were then analyzed at each scale with co-inertia analysis (COIA). Results from COIA indicated that the degree of agreement between the structure of the environmental and shark data sets was relatively higher at the small spatial scale than at the large one. CPUE of Blacktip Shark (Carcharhinus limbatus) was related positively with crustacean biomass at both spatial scales. Similarly, CPUE of Atlantic Sharpnose Shark (Rhizoprionodon terraenovae) was related positively with chl-a concentration and negatively with DO at both spatial scales. Conversely, distribution of Blacknose Shark (C. acronotus) displayed a contrasting relationship with depth at the 2 scales considered. Our results indicate that the factors influencing the distribution of sharks in the northern Gulf of Mexico are species specific but generally transcend the spatial boundaries used in our analyses.

Predicting the distribution of Vibrio vulnificus in Chesapeake Bay

Vibrio vulnificus is a gram-negative pathogenic bacterium endemic to coastal waters worldwide, and a leading cause of seafood related mortality. Because of human health concerns, understanding the ecology of the species and potentially predicting its distribution is of great importance. We evaluated and applied a previously published qPCR assay to water samples (n = 235) collected from the main-stem of the Chesapeake Bay (2007 – 2008) by Maryland and Virginia State water quality monitoring programs. Results confirmed strong relationships between the likelihood of Vibrio vulnificus presence and both temperature and salinity that were used to develop a logistic regression model. The habitat model demonstrated a high degree of concordance (93%), and robustness as subsequent bootstrapping (n=1000) did not change model output (P > 0.05). We forced this empirical habitat model with temperature and salinity predictions generated by a regional hydrodynamic modeling system to demonstrate its utility in future pathogen forecasting efforts in the Chesapeake Bay.

Environmental inventory and the distribution of inorganic nutrients in a tropical estuary of the south-west coast of India

Dissolved nutrients (PO sub(4)-P, NO sub(3)-N, NO sub(2)-N and SiO sub(4)-Si) estimated in the surface and bottom waters of five selected stations of the Paravur Lake, Kerala, India, during February 1987 to January 1988 revealed distinct seasonal variations. Rainfall and land drainage play significant roles in the nutrient economy, particularly NO sub(3)-N and SiO sub(4)-Si, of this water body. Abnormally high values of PO sub(4)-P indicated extremely polluted condition at the wetting zone of the lake during the premonsoon season. SiO sub(4)-Si showed significant negative relationship with salinity.

Seasonal fluctuation in the distribution of eggs and larvae of flat fishes (Pleuronectiformes - Pisces) in the Cochin backwater

Attempts have been made to correlate the abundance of eggs and larvae of flat fishes belonging to families Cynoglossidae and Soleidae with the hydrographical parameters of the environment, particularly the salinity. The eggs and larvae were found to occur in the Cochin backwater during the pre-monsoon period but not during the south west monsoon period. During the south west monsoon period larvae belonging to very early stages were found at the marine end (Fairway Buoy). The continued or prolonged existence of very low salinity appears to restrict the distribution of flat fish larvae. In the post-monsoon period also the eggs and larvae were not found in regions of very low salinity. Larvae of Cynoglossus puncticeps (Richardson), C. brevis Gunther, C. cynoglossus (Ham. Buch), C. lida (Bleeker) and Solea heinii Steindachner were obtained in the collection taken from the estuary. From the data it is seen that each species has specific spawning period.

Distribution of Macrobrachium rosenbergii (de Man) in three rivers of Paikgacha, Bangladesh

Distribution of post larvae, juveniles and adults of Macrobrachium rosenbergii was studied in three rivers of Paikgachha, Khulna during November '91 to Apri1 '94. The adults were found to ascend upstream and the matured ones again return to the estuary to breed. Post larvae of M. rosenbergii prefer a salinity range in between 0.5 to 19.0 ppt and juveniles require a salinity range in between 0.0 to 2.0 ppt.

Observations on the ingression and distribution of larval prawns in the Nethravati-Gurupur estuary, Mangalore

The spatial and temporal distributions of larval prawns of penaeids and non-penaeids in the estuarine waters of Mangalore were studied. Larvae appear to be passively brought in by the incoming flood tides to the estuary, enjoy a wider distribution throughout the estuarine complex with abundance towards the mouth. The distribution of larval prawns was more in Nethravati than in the Gurupur stretch. The influence of temperature, hydrogen-ion-concentration, salinity and dissolved oxygen on the distribution of larvae in the estuaries is discussed. Inference on spawning seasons of commercially important prawns in the neighbouring waters has been arrived at based on their larval abundance.

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.

Distribution of plankton population in shrimp ghers of Bagherhat, Bangladesh

Analysis of plankton sample recorded a total of 5 classes’ phytoplankton viz Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, and Polyhymenophorea. Total 50 phytoplankton species were identified. Among the phytoplankton 18 species belonged to Bacillariophyceae, 12 to Chlorophyceae, 8 to Cyanophyceae, 7 to Dinophyceae, and 5 to Polyhymenophorea. Bacillariophyceae was the dominant group of phytoplankton throughout the study period. Toxin producing dinoflagelates were recorded from the shrimp ghers. A total of 11 kinds of different zooplankton genera were recorded, 4 of which were belonged to Copepoda, 3 to Cladocera, 3 to Rotifera and 1 to Decapoda. Copepoda was the dominant group among the zooplankton which was followed by Rotifera and Decapoda. Temperature varied from 27°C to 32°C, transparency 24.5-29.6 cm and pH 6.7 to 9. Salinity fluctuated from 12 to 32.5‰ in both ghers. PO sub(4)-P and NO sub(3)-N ranged from 0.9 to 4.2 ppm.

Impacts of environmental conditions on macrobenthic distribution along the Suez Gulf, Egypt

Increases in coastal development and human activities leading to sedimentation degrade the quality of water; disturb the natural structure and functions of aquatic communities. The Suez Gulf is a large semi-closed area (~625 km long coastline).The assemblages of bottom fauna were studied qualitatively and quantitatively in the shallow intertidal waters along the western coast of the Suez Gulf. The quality of seawater and sediment structures were analyzed. The distribution of macro-benthos included a total of 38 species of Gastropoda and 9 Bivalvia; and 25 species from the other invertebrates included 7 groups namely, Rhizostoma, Polychaeta, Cirripedia, Amphipoda, Isopoda, Decapoda and Echinodermata. The most dominant group among invertebrate groups was the Polychaeta which included 4 species: Hydroides elegans, Perinereis cultilifera, Perinereis nuntia and Ophelina acuminata. The Cirripedia were represented by 3 species namely, Balanus amphitrite, Chithamalus challengeri and Tetraclita squamosa. The variations in the numerical abundance and biomass of bottom fauna studied between the observation periods and at sampling sites. There was a marked increase in benthos biomass at St. IV (Ras Gharib) yielding an average of 318.8 g/m² in which the gastropod community represented the dominant species in collected samples reaching 270.28 g/m² (84.4% of the total biomass) and numerically numbered 116 ind./m². Veliger larvae of bivalves and gastropods appeared to be present in the plankton for long periods and their production seems to be continuous throughout the year. In the intertidal zone of the Suez Gulf, the values of pH varied within narrow limits. Water temperature and salinity seemed to be important in the distribution and abundance of the macro-benthos communities in the study areas. The organic content in shallow intertidal waters and sediments indicated high values in the central part of the Gulf of Suez.

Identification of biodiversity and distribution pattern of benthic Foraminifera and Ostracoda in continental shelf sediments of the Oman Sea

Biodiversity and distribution of benthic Foraminifera and Ostracoda in the continental shelf sediments of the Omman Sea was studied in order to indicating of the composition of benthic foraminiferal and ostracodal communities and determining of their relationship with the environmental factors of the Omman Sea. Sediment samples were gathered in winter 2006 from twelve stations ranging in depth from 30 to 103 meters. Environmental factors including depth, temperature, salinity, dissolved Oxygen and pH were measured with a CTD system during sampling time and grain size and total organic matter were measured in laboratory. From the overall 57 benthic foram species, there were 52 identified species belong to 25 genera of 16 families. The cosmopolitan foraminifer, Ammonia beccarii, was common in all sampling stations. The composition of benthic foram communities had a highly positive correlation with depth, salinity and total organic matter. From the overall 30 ostracod species, there were 26 identified species belong to 22 genera of 13 families. Diversity and aboundance of ostracoda of the Oman Sea decreased from east to west and from south to north but increased slightly in the northwest (near the Strait of Hormoz). Ostracoda of the genus Propontocypris were common in all sampling stations but the genera Cyprideis, Paradoxostom and Hemicytheridea were rare in the Oman Sea. Diversity and aboundance of ostracoda in northern regions were less than southern and were less than foraminifera too. The composition of ostracodal communities had a highly positive correlation with dept, salinity and grain size. Biodiversity and distribution pattern of benthic foraminifera and ostracoda were being different in various sampling stations, especially between northern and southern regions. Water depth, salinity and structure of the sediments were the most important abiotic factors controlling the distribution pattern of benthic foraminifera and ostracoda in the Omman Sea. None existence or rare observation of structural abnormalities and oil polluted individuals in the vicinity of all sampling stations, resulted to the "clean" benthic environment of the Omman Sea.

Distribution and growth biology of rock oyster Saccostrea cucullata in the Oman Sea

Distribution and growth biology of rock oyster (Saccostrea cucullata) in the northern shores of Oman sea have been struied. During this one-year study, samples have been taken monthly from ten different stations. quantity of vertical distribution of this species was obseredl in the mid - intertidal zone. After determining the spread pattern, the following subjects were studied: - Growth parameters - Distionction of the "cohorts" - Determination of "spawning Season" - Condition of the "Gonado Somatic Index" - Sex ratio - Length of the species during the first year of maturation. - Identification and determination of percentage of "Biofouler Organisms." Results obtained from the above - mentioned studies show that considering a growth factor (k) of 0.52, the value of "Loo " for this species is equal to 114 (mm).Five to six different age groups were observed among the samples taken. In the areas where this study was conducted, this species grows 24 to 30 (mm) in the first year of its life this growth rate is lower in the higher - aged grpups relative to the lewer - aged groups, so that the longest size classes grow between 4 to 6 (mm) per year. • The maxinum Value of the "Condition Index" is in the pozm area and the minimum value of it belongs to Darak and Tang areas. Along with the increase in the growth of gonads the above mentioned condition index increases gradually simultaneous with the onset of spawning. Also, study of the influence of environmental factors on the maturation process suggests that the most important factors affecting maturation and spawing are temperature and salinity. The study of GSI shows that this species has a coordinated bimodal spawing trend, with its spring peak in june and its autumn peak, being still higher than the spring peak, in september. The recruitment curve confirms the above spawning peaks with its peaks occuring after a delay of one month or maximum two months in comparison to the spawning peaks. The results of calcuation of "Sex Ratio" of this species in each area show that sex ratio is 1:1. Among the first size classes that reach maturity, nearly 67% of the samples are male and the remaining 33% are female. with the increase in the shell size, the percentage of males decreases and the percentage of females increases. , The above facts prove the protandrous nature of this species the diagram showing the sizes of the first samples which reach maturity suggests that more than 50% of the samples mature after their length exceeds 36 (mm). The shortest mature sample was found to have a length of 22(mm). After studying "Biofouler Organism" nine different invertebrate groups were indentified. Barnacles and Tunicates have the highest and lowest percentages respectively. According to zonal observations, Barnacles and polychacta do the greatest damage to this species.