scholarly journals Species identification in seamount fish aggregations using moored underwater video

2012 ◽  
Vol 69 (4) ◽  
pp. 648-659 ◽  
Author(s):  
Richard L. O'Driscoll ◽  
Peter de Joux ◽  
Richard Nelson ◽  
Gavin J. Macaulay ◽  
Adam J. Dunford ◽  
...  
Keyword(s):  
Species Identification ◽  
Deep Water ◽  
Underwater Video ◽  
Orange Roughy ◽  
Video Cameras ◽  
Order Of Magnitude ◽  
Acoustic Surveys ◽  
To Come ◽  
Along Track ◽  
Fish Response

Abstract O'Driscoll, R. L., de Joux, P., Nelson, R., Macaulay, G. J., Dunford, A. J., Marriott, P. M., Stewart, C., and Miller, B. S. 2012. Species identification in seamount fish aggregations using moored underwater video. – ICES Journal of Marine Science, 69: 648–659. Acoustic surveys of New Zealand deep-water seamounts often show fish aggregations up to 150 m high on the summit. Although bottom trawls on the seamount slopes catch predominantly orange roughy (Hoplostethus atlanticus), species composition in the midwater plumes is extremely uncertain. In June 2010, moored underwater video cameras were deployed on the summit of the Morgue seamount (summit depth 890 m), a feature that has been closed to fishing since 2001. Cameras and lights were timed to come on for 2 min every 2 h. Fish response to the mooring was monitored using vessel-mounted echosounders. Moored cameras confirmed that orange roughy were present up to 70 m above the seamount summit. Orange roughy made up 97% of the fish identified from the video. Other species observed included smooth oreo (Pseudocyttus maculatus), spiky oreo (Neocyttus rhomboidalis), deep-water dogfish, cardinalfish (Epigonus spp.), and squid. Total along-track backscatter from the plume varied by a factor of 25 over a period of hours. Peak acoustic densities in the plume (equivalent to 20 orange roughy m−3) were an order of magnitude higher than peak visual estimates (0.64 orange roughy m−3), but relative densities between paired video and acoustic observations were generally consistent.

Species identification in deep water using multiple acoustic frequencies

2002 ◽  
Vol 59 (6) ◽  
pp. 1065-1077 ◽  
Author(s):  
R J Kloser ◽  
T Ryan ◽  
P Sakov ◽  
A Williams ◽  
J A Koslow
Keyword(s):  
Simple Model ◽  
Species Identification ◽  
Deep Water ◽  
Standard Length ◽  
Positive Bias ◽  
Orange Roughy ◽  
Uncertainty Factor ◽  
Spawning Site ◽  
Dominant Fish ◽  
Hoplostethus Atlanticus

Multifrequency 12, 38, and 120 kHz acoustics were used to identify the dominant fish groups around a deepwater (>600 m) seamount (a known spawning site for orange roughy, Hoplostethus atlanticus) by amplitude mixing of the frequencies. This method showed three distinct acoustic groupings that corresponded to three groups of fishes based on size and swimbladder type: myctophids of total length less than 10 cm, morids and macrourids with lengths >30 cm, and orange roughy with a mean standard length of 36 cm. These three groups were the dominant groups caught in the demersal and pelagic trawls in the study area. A simple model of swimbladder resonance at depth of large and small gas-filled bladder fish groups is in agreement with our experimental observations. Traditionally, demersal and pelagic trawling is used to identify fish species in acoustic records. However, orange roughy are rarely caught in mid-water owing to net avoidance. Using three frequencies, these groups could be distinguished directly over their entire vertical extent from the acoustic records. This reduces a major source of positive bias uncertainty (factor range of 2.0–6.4) in the orange roughy biomass estimates.

scholarly journals Current extinction rate in European freshwater gastropods greatly exceeds that of the late Cretaceous mass extinction

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Thomas A. Neubauer ◽  
Torsten Hauffe ◽  
Daniele Silvestro ◽  
Jens Schauer ◽  
Dietrich Kadolsky ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Recovery Period ◽  
Freshwater Ecosystems ◽  
Extinction Rate ◽  
Freshwater Gastropods ◽  
Extinction Rates ◽  
Freshwater Biota ◽  
Order Of Magnitude ◽  
To Come ◽  
Mass Extinction Event

AbstractThe Cretaceous–Paleogene mass extinction event 66 million years ago eradicated three quarters of marine and terrestrial species globally. However, previous studies based on vertebrates suggest that freshwater biota were much less affected. Here we assemble a time series of European freshwater gastropod species occurrences and inferred extinction rates covering the past 200 million years. We find that extinction rates increased by more than one order of magnitude during the Cretaceous–Paleogene mass extinction, which resulted in the extinction of 92.5% of all species. The extinction phase lasted 5.4 million years and was followed by a recovery period of 6.9 million years. However, present extinction rates in European freshwater gastropods are three orders of magnitude higher than even these revised estimates for the Cretaceous–Paleogene mass extinction. Our results indicate that, unless substantial conservation effort is directed to freshwater ecosystems, the present extinction crisis will have a severe impact to freshwater biota for millions of years to come.

scholarly journals An Estimation of Fish Biomass and Attached Organisms beneath Oyster Rafts in Hiroshima Bay, Japan

2021 ◽  
Vol 324 ◽  
pp. 03013
Author(s):  
Wahyudin Wahyudin ◽  
Tamiji Yamamoto
Keyword(s):  
Large Scale ◽  
Fish Habitat ◽  
Food Chains ◽  
Ecosystem Structure ◽  
Fish Production ◽  
Underwater Video ◽  
Oyster Culture ◽  
Video Cameras ◽  
Black Seabream ◽  
Material Cycles

Hiroshima Bays is top production approximately 60% of oyster production in Japan. For cultivate of oyster, fishermen use hanging rafts. A thousand of raft is hanging during 2-3 years in the bay. Large-scale oyster culture may change the ecosystem structure and material cycles in the bay through the filtration of particulate matter by oysters and other associated animals. This study described the community structure of marine organisme in terms of fishes surrounding and animal attached on oyster rafts. Field observation was carried out from 2016 to 2019 at oyster farming in Hiroshima Bay. Oyster production and provisioning for the fish habitat were also evaluated by placing underwater video cameras beneath oyster culture rafts. The result showed that black seabream was high biomass and oyster it shelf was bigger bioyster for animal attached on oyster raft. The number of individual, mussel is most abundance of animal attach on oyster raft with ratio 9:1 than number of oyster. Maintaining oyster culture is important not only for maintaining oyster production, but also for maintaining fish production by enhancing material cycles through the paths in the food chains of Hiroshima Bay under oligotrophic conditions.

Target strength of an oily deep-water fish, orange roughy (Hoplostethus atlanticus) I. Experiments

1999 ◽  
Vol 106 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Sam McClatchie ◽  
Gavin Macaulay ◽  
Roger F. Coombs ◽  
Paul Grimes ◽  
Alan Hart
Keyword(s):  
Deep Water ◽  
Target Strength ◽  
Orange Roughy ◽  
Water Fish ◽  
Hoplostethus Atlanticus

scholarly journals Wave resistance : some cases of unsymmetrical forms

1926 ◽  
Vol 110 (754) ◽  
pp. 233-241 ◽  
Keyword(s):  
Mathematical Problem ◽  
Dynamical Theory ◽  
Wave Resistance ◽  
Experimental Results ◽  
General Effect ◽  
Surrounding Water ◽  
Order Of Magnitude ◽  
To Come ◽  
The Waves ◽  
Two Bodies

1. One of the chief features of interest in curves showing the variation of wave resistance with velocity is the occurrence of oscillations about a mean curve, which may be regarded as due to interference between the waves produced by the front and rear portions of the model. In various comparisons made between theoretical curves and such suitable experimental results as are available, the greatest divergence is perhaps in the magnitude of these oscillations, the theore­tical curves showing effects many times greater than similar experimental results. There are, no doubt, many approximations in the hydro-dynamical theory which preclude too close a comparison between theoretical and experimental results in any particular case, but it seems fairly certain that the divergence in question must be largely due to neglecting the effects of fluid friction. For several reasons it is useless to attempt at present a direct introduction of vis­cosity into the mathematical problem, but a consideration of its general effect suggests one or two calculations which may be of interest The direct effect of viscosity upon waves already formed may be assumed to be relatively small; the important influence is one which makes the rear portion of the model less effective in generating waves than the front portion. We may imagine this as due to the skin friction decreasing the general relative velocity of model and surrounding water as we pass from the fore end to the aft end ; or we may picture the so-called friction belt surrounding the model, and may consider the general effect as equivalent to a smoothing out of the curve of the rear portion of the model. Without pursuing these speculations further, they suggest calculations which can be made for models in frictionless liquid when the form of the model is unsymmetrical in this manner ; and the particular point to be examined is the effect of such modification upon the magnitude of the inter­ference phenomena. The first sections compare, in this respect, two bodies entirely submerged in the liquid. The form in each case is a surface of revolution ; one is symmetrical fore and aft and has sharp pointed ends, while in the other the rear portion is cut away so as to come to a fine point. By inspection of the expressions for the wave resistance it is seen that the oscillating terms are of a lower order of magnitude in the latter than in the former case.

BIOCHEMICAL STUDIES ON THE IODINE ORGANIFICATION DEFECT OF PENDRED'S SYNDROME

1978 ◽  
Vol 89 (1) ◽  
pp. 70-79 ◽  
Author(s):  
Hugo Niepomniszcze ◽  
Aldo H. Coleoni ◽  
Osvaldo J. Degrossi ◽  
Luis M. Scavini ◽  
H. Pablo Curutchet
Keyword(s):  
Kinetic Studies ◽  
Iodine Content ◽  
Thyroid Peroxidase ◽  
Enzyme Preparations ◽  
Biochemical Studies ◽  
Order Of Magnitude ◽  
Km Value ◽  
Pendred’S Syndrome ◽  
To Come ◽  
Organification Defect

ABSTRACT Biochemical studies were performed on the thyroid of a typical case of Pendred's syndrome who underwent total thyroidectomy. The patient, a euthyroid 14 year old female, presented congenital nerve deafness, goitre and impairment of thyroidal iodine organification. Thyroid peroxidase (TPO) activity was quantitatively normal. Using crude preparations, enzyme activity ranged from 176–366 nmoles of I−-incorporated (inc.) to tyrosine/g of tissue. Normal values are 220–410 nmoles I− inc./g. Digitonin pseudosolubilized TPO, assayed by the tyrosine-iodinase method, showed 44.9 nmoles I− inc./mg of protein for the Pendred's tissue, and 44.5 nmoles I− inc./mg for the control glands. Soluble TPO was utilized for enzyme-kinetic studies. The Km for H2O2, obtained in the triiodide assay with iodide as hydrogen donor, was in the same order of magnitude for both Pendred's and control thyroids, being 3 × 10−4 m and 3.5 × 10−4 m, respectively. In the guaiacol assay, the Pendred's Km value of 4 × 10−4 m was also normal for H2O2. Pre-incubation of enzyme preparations with 5 × 10−5 m haematin did not stimulate TPO activity. Thyroidal NADPH-cytochrome c reductase and monoamine oxidase activities were normal. A low concentration, 37 mg/g, of a qualitatively normal thyroglobulin was found in Pendred's goitre. The iodine content of thyroglobulin was 0.19 %. It is concluded that the four major components of the iodination process: 1) thyroid peroxidase, 2) iodide, 3) thyroglobulin and 4) H2O2 would be normally present in Pendred's glands. It is postulated that a failure of these major components to come together at the iodination site might be the explanation of the organification defect of Pendred's syndrome.

scholarly journals Measurement and visual verification of fish target strength using an acoustic-optical system attached to a trawlnet

2009 ◽  
Vol 66 (6) ◽  
pp. 1238-1244 ◽  
Author(s):  
Tim E. Ryan ◽  
Rudy J. Kloser ◽  
Gavin J. Macaulay
Keyword(s):  
Optical System ◽  
Deep Water ◽  
Video Camera ◽  
Target Strength ◽  
Dual Frequency ◽  
Low Light ◽  
Orange Roughy ◽  
Video Images ◽  
Acoustic Target ◽  
Frequency Split

Abstract Ryan, T. E., Kloser, R. J., and Macaulay, G. J. 2009. Measurement and visual verification of fish target strength using an acoustic-optical system attached to a trawlnet. – ICES Journal of Marine Science, 66: 1238–1244. It is difficult to make acoustic target-strength (TS) measurements of fish behaving naturally in deep-water habitats. The fish may avoid the acoustic instrumentation, and, if measured, there is uncertainty about their species and their orientation relative to the incident sound. To address these issues, a novel acoustic-optical system (AOS) has been developed, which combines a battery-powered, dual-frequency, split-beam acoustic system with a low-light video camera. The AOS attaches to the headline of a commercial deep-water demersal trawlnet that herds fish past the AOS and to the codend. This paper describes initial trials of the AOS to measure calibrated TS of New Zealand orange roughy, validated with video images. The fish species were visually identified, and their behaviour and orientation were approximated. The trawl catch provided associated samples for species identification and measurements of their length and other biological metrics. The combination of acoustics and optics in a net-mountable system constitutes a powerful sampling tool with broader applications in fishery research and ecosystem investigations.

ARE WE AT THE END OF CMOS SCALING?

2006 ◽  
Vol 16 (01) ◽  
pp. 3-8 ◽  
Author(s):  
GHAVAM G. SHAHIDI
Keyword(s):  
Power Density ◽  
Cmos Technology ◽  
Active Power ◽  
Information Revolution ◽  
Performance Gain ◽  
Technology Node ◽  
Cmos Scaling ◽  
Order Of Magnitude ◽  
To Come

CMOS scaling enabled by advances in lithography has been behind the information revolution. Over the last 15 years, there has been a new CMOS technology node approximately every two years. The key feature of every node has been 2X density shrink and ~35% performance gain per technology node. At 90 nm node a number usual knobs that have enabled the scaling have approached their limits. Furthermore chip power (both active and stand-by) has been increasing rapidly, approaching air cool limit. Chip stand-by power, which was negligible a few years ago, is now about the same order of magnitude as the active power in high end microprocessors. In this talk it will be argued that because of power density limitation of 90 nm, 65 nm, and beyond nodes, performance and ability to shrink are more than ever linked, and in fact if the performance gain would significantly slow down (for the designs that operate at the existing cooling limit). It is more than ever critical to come up with technology features that will enhance the performance, at a given device leakage.

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