Growth,diet, movement,and abundance of adult banded kokopu (Galaxias fasciatus) in five Coromandel,New Zealand streams

Banded kokopu populations were surveyed seasonally over 1 year in five Coromandel streams to determine the influence of food supply on diet, growth, abundance, and movement. Streams with high benthic invertebrate abundance and drift of aquatic origin had high fish abundance. However, terrestrial drift was the dominant food for adult banded kokopu over all seasons and streams, on average comprising 75% of their diet by number and 89% by weight. Annual growth rates of tagged individuals ranged from 3 mm to 16.5 mm, with smaller fish growing faster than large fish. Low growth rates of large fish were consistent with the recapture of a fish that had only grown from 195 mm to 215 mm in 7 years. Our observations confirmed the strong association between banded kokopu, pool habitat, and cover, and also indicated that high fish abundance restricted growth rates and movement and increased interaction.     

Ecology of rocky reef fish of northeastern New Zealand: 50 years on

Abstract

This review examines the history and current understanding of the ecology of rocky reef fishes in northeastern New Zealand, marking the fiftieth anniversary of the Leigh Marine Laboratory. The cumulative number of publications increased steadily to c. 180 by 2012. Most attention has been on the snapper (Pagrus auratus, f. Sparidae), the largest in size and economically most important species, and on triplefins (Tripterygiidae), the smallest in size and most diverse family. A strong quantitative school emerged in the 1980s, a period when there was little research on temperate reef fishes elsewhere. A ‘bottom-up’ view of the effects of habitat structure on fish emerged, identifying the key roles of depth, topography and macroalgae. By 2000, attention shifted to using marine reserves as laboratories for ecological research. A ‘top-down’ view of fish as predators emerged, documenting cascading effects on prey communities and habitats. The two different viewpoints have not yet been integrated. Research gaps, including population connectivity and climate change, represent major challenges for the next 50 years.     

Does thermal history influence the tolerance of temperate gorgonians to future warming?

To date, several studies have provided evidence that thermal stress affects the growth, survival and physiology of tropical and temperate macroinvertebrate species. However, few studies have focused on subtidal temperate species and the potential differential thermal tolerances of populations dwelling under contrasting temperature conditions. To assess the role that environmental history has on the response of the temperate gorgonian Eunicella singularis to thermal stress, we compared populations dwelling in the coldest and warmest areas of the NW Mediterranean Sea. Our results show that E. singularis populations from both areas exhibited a high resistance to thermal stress; however, populations from warmer areas had an increased tolerance to thermal stress. Specifically, the upper thermal limits found for cold and warm populations were 28 and 29 °C, respectively. The higher resistance of E. singularis colonies to thermal stress found in this study compared to the field temperature conditions during recent mass mortality events highlights that performing further thermotolerance experiments under contrasting levels of feeding is necessary to fully assess the tolerance thresholds displayed by both study populations. To our knowledge, this study provides the first evidence for the role of thermal history in shaping the thermotolerance responses of Mediterranean marine invertebrates dwelling under contrasting temperature environments.     

Behavioral responses of a harbor porpoise (Phocoena phocoena) to playbacks of broadband pile driving sounds

The high under-water sound pressure levels (SPLs) produced during pile driving to build offshore wind turbines may affect harbor porpoises. To estimate the discomfort threshold of pile driving sounds, a porpoise in a quiet pool was exposed to playbacks (46 strikes/min) at five SPLs (6 dB steps: 130–154 dB re 1 μPa). The spectrum of the impulsive sound resembled the spectrum of pile driving sound at tens of kilometers from the pile driving location in shallow water such as that found in the North Sea. The animal's behavior during test and baseline periods was compared. At and above a received broadband SPL of 136 dB re 1 μPa [zero-peak sound pressure level: 151 dB re 1 μPa; t₉₀: 126 ms; sound exposure level of a single strike (SEL_ss): 127 dB re 1 μPa² s] the porpoise's respiration rate increased in response to the pile driving sounds. At higher levels, he also jumped out of the water more often. Wild porpoises are expected to move tens of kilometers away from offshore pile driving locations; response distances will vary with context, the sounds' source level, parameters influencing sound propagation, and background noise levels.     

Discordant patterns of genetic connectivity between two sympatric species,Mullus barbatus (Linnaeus, 1758) and Mullus surmuletus (Linnaeus, 1758), in south-western Mediterranean Sea

Population connectivity scales are important tools to achieve a mechanistic understanding of the factors regulating the abundance and distribution of marine populations and therefore support conservation actions to manage fisheries and stocks. We used 10 microsatellites markers on mullets' samples across the Spanish coast to determine the spatial scale of gene flow as well as the origin of post-larvae caught inside two MPAs. Population structure varied from complete homogeneity for Mullus barbatus, to high spatial variability in Mullus surmuletus samples. Differential habitat utilization by species, geomorphological features and oceanographic patterns are discussed as potential causes of patterns observed. Although we were unable to verify the origin of most post-larvae caught inside MPAs we suggest that they may act as genetic reservoirs due to high heterozigosity levels found in adult specimens inside (M. surmuletus) and nearby (both) them. Our results indicate that early life history traits (i.e. larvae) may not be the only determinant on species dispersal capability, suggesting that other mechanisms such as fine scale adult or juvenile movement may have been underestimated as promoting population connectivity.     

The national geophysical data center bathymetric program

The National Geophysical Data Center's (NGDC's) mission is data management in the broadest sense, playing a role in the nation's research into the environment and providing data to a wide group of users. NGDC also operates components of the International Council of Scientific Unions (ICSU) World Data Center A. The Marine Geology and Geophysics Division of NGDC handles bathymetric data acquisition, manipulation, archival, and dissemination and operates the International Hydrographic Organization Data Center for Digital Bathymetry. Four major data bases have been developed to manage the large volume of data received: the Global Marine Geophysical Data Base (geophysical data acquired in a time series); the NOAA National Ocean Service Hydrographic Data Base; the International Hydrographic Data Base (contains bathymetric data, other than NOS surveys, with no time‐tagging); and the Multibeam Bathymetric Data Base. In addition, gridded data sets such as ETOPO5 are available from NGDC. Bathymetric data are acquired by NGDC through data exchange, funded and contract programs, processing of long‐term data holdings, data digitization from hardcopy sources, and national and international linkages. NGDC personnel participate nationally and internationally on numerous committees associated with studies of the seafloor including charting and bathymetric needs.     

Contributions expected from marine geodesy to the study of tsunamis in the Mediterranean Sea

Abstract

In the Mediterranean Sea, tsunamigenic sources may be found in several areas in the belt running from Gibraltar up to the Black Sea, but they are concentrated mainly around Italy and Greece. Most of the sources are located close to the coasts and excite tsunamis reaching the coasts soon after the generation time. Tsunami research and tsunami mitigation programs are only in a very initial stage in the Mediterranean area. The present activities are focused chiefly to tsunami potential evaluation and on tsunami propagation modeling. The establishment of efficient observational networks, centers for data management and services, and systems for issuing tsunami warnings are some of the most urgent needs. In this context, the envisaged contribution of marine geodesy is twofold. First, monitoring of submarine active faults and submarine volcanic areas by means of systems capable of detecting seafloor deformation may contribute in identifying periods in which the probability of tsunami generation increases beyond a threshold value, especially in those tsunamigenic zones where geodetic observations on land are insufficient (for example, eastern Sicily in Italy and the Hellenic Arc in southern Greece). Second, since most of the active sources are close to the coastline, computations of tsunami propagation and run‐up may be significantly enhanced by a better knowledge of the bathymetry of the seabelt facing the coasts.     

Sulphate Attack in Lime-Treated Marine Clay

ABSTRACT

The use of lime to improve the properties of soft clays is not new. Recently the deep lime mixing technique has been extended to coastal regions for improving the behavior of weak marine clays. But lime treatment technique should be approached carefully for clay containing a high percentage of sodium sulphate. The presence of sulphate in lime-treated clays may result in high swelling due to the formation of the expansive mineral, ettringite. A limited study of lime-treated marine clays has shown a need to further explore the formation of ettringite and its stability with time. In this article, a laboratory investigation was carried out to examine the influence of sodium and calcium sulphates on the behavior of lime column treated marine clay. Scanning electron microscopy (SEM) was used to identify the formation of various reaction products, including ettringite. Test results indicate that the formation of ettringite in the lime-sodium sulphate-clay system adversely affects the engineering behavior of the marine clay, whereas the addition of calcium sulphate significantly improves the engineering characteristics of the soil.