Search results
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Age–length composition of mackerel icefish (Champsocephalus gunnari, Perciformes, Notothenioidei, Channichthyidae) from different parts of the South Georgia shelf
Y Y a C T K O B . I l p e ~ n o n a r a e ~ c ~ , Y T O Y a c T b 3 a n a n ~ o E rpynnrrpoerw pb16bl M c t r p n p y e T K c K a n a M UIar Ha BTOPOM-TpeTheM rOny XM'3H11 ... - spent (end of spawning). The shelf area was divided into five regions, each containing approximately ... effort usually decreased for a short period (1-2 years) after which it again intensified, yielding ... as high-intensity fishing (1980s). Trawl surveys carried out several years after the ban on fishing ... , Notothenioidei, Channichthyidae) from different parts of the South Georgia shelf Abstract / Description ... determine the age-length composition of mackerel icefish (Champsocephalus gunnari) from different parts of ... the South Georgia area. An analysis of the spatial distribution of C. gunnari size and age groups over ... the eastern, northern, western and southern parts of the shelf, and near Shag Rocks, revealed a ...
Science Journal Paper : CCAMLR Science, Volume 8 (CCAMLR Science, Volume 8) : 133–146 : Author(s): Frolkina, G.A
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Calibration of an acoustic echo-integration system in a deep tank, with system gain comparisons over standard sphere material, water temperature and time
the signal digitally immediately following the receiver front end. Therefore, changes in gain are effected ... by 3 m in diameter. It was filled with ocean water pumped from the end of Scripp's pier. A pump and refrigeration ... . Therefore, if no data were collected exactly on axis, the nearest data to the axis were used after being ... the survey. The calibration should be repeated at least twice, before and after the survey. The results ... outlines the theory and procedures for calibrating an echo integration acoustic system with a standard ... sphere. It presents the results of an extensive calibration of a Simrad EK500 scientific echosounder with ... length (0.1, 0.3 and 1.0 ms), target depth (0.8 to 7.5 m), and time (149 days). The total range in TS ... gain, including the effects of temperature, standard sphere and time, is 2.9 dB. Gain values calibrated ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/9 (Selected Scientific Papers, SC-CAMLR-SSP/9) : 127–144 : Author(s): Demer, D.A. and R.P. Hewitt
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Sensitivity investigation of the SDWBA Antarctic krill target strength model to fatness, material contrast and orientation
approximation model is recognised as stateoftheart in predicting acoustic target strength (TS) from ... is re cognised as stateoftheart in predicting TS from fluidlike zooplankton (Stanton and Chu, 2000 ... ) lengthdependent relationships: g = 5.439 × 10–4 L + 1.002 and h = 4.981 × 10–4 L + 1.009. At the end ... Paper Title: Sensitivity investigation of the SDWBA Antarctic krill target strength model to ... fatness, material contrast and orientation Abstract / Description: The distorted-wave Born approximation ... model is recognised as state-of-the-art in predicting acoustic target strength (TS) from fluid-like ... marine organisms. A stochastic version, the so-called SDWBA model, is endorsed by CCAMLR to predict the ...
Science Journal Paper : CCAMLR Science, Volume 18 (CCAMLR Science, Volume 18) : 97–122 : Author(s): Calise, L. and G. Skaret
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A comparison between otoliths and scales for use in estimating the age of Dissostichus eleginoides from South Georgia
for several months after hatching, or annuli in older fish can be obsc~lred by compression of the circuli ... . Annual mortality was considered high after maturity even though active growth continued. By contrast ... after growth slowed or ceased. Yearly annuli on scales were difficult to identify after age ... , so that the outer annulus was counted as one year if the fish was taken after 1 July but not before ... Paper Title: A comparison between otoliths and scales for use in estimating the age of ... understanding the population dynamics and productivity of a fish stock. The use of scales to estimate age can ... whose age has been estimated using both scales and otoliths. We estimated the age of D. eleginoides ... ; for otoliths, we used transverse sections prepared by baking and grinding the posterior and anterior ...
Science Journal Paper : CCAMLR Science, Volume 8 (CCAMLR Science, Volume 8) : 75–92 : Author(s): Ashford, J.R., S. Wischniowski, C. Jones, S. Bobko and I. Everson
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Target strengths of krill at 136 and 20 kHz
the catch and placed in a container of sea-water. After sorting, groups of various numbers of live ... in the cage using a funnel. The length of krill in the cage were then measured at the end of each test ... to 15 m. TS values for the empty cage and the cage containing krill were recorded 40 minutes after ... the cage after the test in another container were actively swimming. 3.1.2 Target strength (TS ... . Ensonification of encaged live krill. For aggregations with mean lengths from 45 to 50 mm the mean single-krill ... the mean single-krill target strengths range from-71 to-77 dB at 20 kHz. Trawl hydroacoustic method ... . For aggregations with mean lengths from 47 to 50 mm the mean target strengths ranged from-71 to-75 dB ... . At the same frequency for aggregations with mean lengths in the range 41 to 47 mm the mean single ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/8 (Selected Scientific Papers, SC-CAMLR-SSP/8) : 141–157 : Author(s): Kasatkina, S.M.
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Management and assessment options for the crab fishery around South Georgia
). Quotas are set after predicting abundances by annual trawl surveys. Catches, catch-per- unit-effort ... the nominal end-of-season, either when the quota is reached or for other biological reasons. Exclusive area ... and 700 m, at the lower end of the depth range of P. spinosissima. In 1979, a single fishing vessel ... of the size and heterogeneous nature of the terrain. Only after investigation of data at the finest scale ... Paper Title: Management and assessment options for the crab fishery around South Georgia Abstract ... / Description: A new fishery for the lithodid crab, Paralomis spinosissima, started in Subarea 48.3 in 1992 ... . The fishery is also new to CCAMLR, both in terms of the species and fishing gear. We provide an ... overview of the management options for crab fisheries in general and then consider these options in the ...
Science Journal Paper : CCAMLR Science, Volume 1 (CCAMLR Science, Volume 1) : 193–202 : Author(s): Basson, M. and D.D. Hoggarth
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Estimation of effective sample size for catch-at-age and catch-at-length data using simulated data from the Dirichlet-multinomial distribution
(glm) examined is that of estimating yn′ in the above way after fitting this sim- ple linear ... , after removing SLOF, is given by ˆˆ ˆ /y yn n′′ ′= Φ. This adjustment is based on Finney’s ... , M, was varied also as a lognormal variable about a mean of 0.13 with CV (cM) of 0.2 from the beginning ... , but after this period M was varied linearly starting at 0.1055 for year 1 and increasing to 0.1544 by year ... simulated data from the Dirichlet-multinomial distribution Abstract / Description: The incorporation of ... ‘effective sample size’ (ESS) in integrated assessments is an approximate but simple way of modelling the ... heterogeneity within fishing year was simulated using samples from the Dirichlet-multinomial (D-M) distribution ... its variants. One of the methods is based on the lack-of-fit of predictions of class probabilities ...
Science Journal Paper : CCAMLR Science, Volume 15 (CCAMLR Science, Volume 15) : 115–138 : Author(s): Candy, S.G
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Killer whale (Orcinus orca) and sperm whale (Physeter macrocephalus) interactions with longline vessels in the Patagonian toothfish fishery at South Georgia, South Atlantic
the mid- positions of all sets, defi ned as the mid-point between the start and end positions, were ... , temporal patterns and the effect on catch rates. After the 2000 season, in order to standardise marine ... . Interactions with killer whales were most often observed in the afternoon after midday (46% of interactions ... % of sightings. Killer whale interactions with fi shing operations still occurred after sunset, being present ... with longline vessels in the Patagonian toothfish fishery at South Georgia, South Atlantic Abstract ... 169 to 2 150 m. Most effort was concentrated along the 1 000 m depth contour. Sperm whales were the ... most abundant marine mammal observed in the vicinity of vessels when lines were being hauled, being ... present during 24% of hauling observations. Killer whales, the second most frequently sighted cetacean ...
Science Journal Paper : CCAMLR Science, Volume 11 (CCAMLR Science, Volume 11) : 111–126 : Author(s): Purves, M.G., D.J. Agnew, E. Balguerías, C.A. Moreno and B. Watkins
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The use of analysis of penguin stomach contents in simultaneous study of prey and predator parameters
Days frorn beginning of sampling Jan 19 1988 ~ Means (krill) Figure 1: Krill size as a function ... Paper Title: The use of analysis of penguin stomach contents in simultaneous study of prey and ... sensitive to the statistical assumptions made during the analysis of data. The nested ANOVA method is ... proposed as being the correct approach for analysis because lack of independence between krill specimens ... found in the stomach of a given penguin prevents the pooling of krill lengths from different samples ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/6 (Selected Scientific Papers, SC-CAMLR-SSP/6) : 367–375 : Author(s): Marschoff, E. and B. González
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Archival and satellite-linked data recorders
by 35mm after allowing for a pressure housing. Obviously this is too large for small penguins ... on a stalk extending from one end of the unit. Temperature is measured at the end of the stalk and also ... behaviour. The records can be recovered in one of two ways: the data recorder must either be recovered ... intact, or the data recorder must be capable of disseminating its data via a radio link, such as the ... . Raw-data recorders keep a complete record of the diving parameters of interest and thus produce ... . Due to the limited data-handling capacity of the ARGOS satellite system, most satellite-linked ...
Science Journal Paper : Selected Scientific Papers, SC-CAMLR-SSP/4 (Selected Scientific Papers, SC-CAMLR-SSP/4) : 475-493 : Author(s): Hill, R.D.