A fishery-independent assessment of an overfished rockfish stock, cowcod (Sebastes levis), using direct observations from an occupied submersible

2007 ◽  
Vol 64 (12) ◽  
pp. 1795-1804 ◽  
Author(s):  
Mary M Yoklavich ◽  
Milton S Love ◽  
Karin A Forney
Keyword(s):  
Fishery Management ◽  
Line Transect ◽  
Fish Length ◽  
Conservation Areas ◽  
Direct Observations ◽  
Length Relationship ◽  
The Pacific ◽  
Mean Size ◽  
Precipitous Decline ◽  
Independent Assessment

A meaningful assessment of cowcod (Sebastes levis) has been conducted using visual, nonextractive, habitat-specific methods. Following the precipitous decline of rockfish (Sebastes spp.) stocks along the Pacific coast, it was evident that more effective methods were needed to assess several species in untrawlable habitats. Cowcod were surveyed within large Cowcod Conservation Areas (CCAs) off southern California using direct observations from the research submersible Delta over eight major offshore rocky banks in depths of 74 to 322 m. Maps of seafloor substratum and bathymetry were used to identify and quantify these areas. A line-transect analysis of fish counts, perpendicular distances of fish from the track line, lengths of survey tracks, and area of each rocky bank was used to estimate abundance. Biomass, calculated from abundance, fish length, and a weight–length relationship, varied with mean size of cowcod on these banks. These fishery-independent results have contributed to the recent assessment of cowcod by the Pacific Fishery Management Council. A time series of results from visual surveys is now necessary to evaluate a trend in cowcod biomass with respect to increased time of protection within the CCAs.

Fecundity of the American Plaice, Hippoglossoides platessoides (Fabr.) from Grand Bank and Newfoundland Areas

1964 ◽  
Vol 21 (3) ◽  
pp. 597-612 ◽  
Author(s):  
T. K. Pitt
Keyword(s):  
Egg Production ◽  
Fish Length ◽  
Northern Slope ◽  
Southern Slope ◽  
Ovary Weight ◽  
Length Relationship ◽  
Relationship Of ◽  
Hippoglossoides Platessoides

Fecundity estimates were made on a total of 140 mature American plaice from the southern and northern slopes of the Grand Bank and from St. Mary's Bay. Log–log relationships were established between fecundity and fish length, gutted and gilled weight, age, and ovary weight. No differences were found to exist between the fecundity–length relationship of plaice from the three areas, but there is a suggestion that within areas there may be annual differences in egg production. At comparable ages plaice from the southern slope of the Grand Bank are larger in size and produce more eggs than those from the northern slope and St. Mary's Bay.

Prior Determination of Flash Floods: Artificial Intelligence Based Predictive Analysis Using Modified Cuckoo Search

2020 ◽  
Vol 17 (2) ◽  
pp. 990-995
Author(s):  
Talha Ahmed Khan ◽  
Muhammad Alam ◽  
Kushsairy Kadir ◽  
Zeeshan Shahid ◽  
M. S. Mazliham
Keyword(s):  
Artificial Intelligence ◽  
Water Pressure ◽  
Cuckoo Search ◽  
Flash Floods ◽  
Rapid Identification ◽  
Predictive Analysis ◽  
Direct Observations ◽  
The Pacific ◽  
The Pacific Ocean

Flash floods are considered as the most intense hazard therefore rapid identification is needed. Tsunami also causes flash floods as it is commonly generated around the Pacific Ocean. Flash floods are also caused by the severely blocked streams in heavy rainfall. Floods have ended up so many lives more than the other natural hazards and also devastated precious belongings and infrastructures. Cattles have also been affected by the floods event. Floods devastate the construction and infrastructure like roads, bridges and buildings that comes in the vicinity of effected area by flood. Breakdown and overflow of dams may produce the deadly flash floods to the populated area and environs. Many strategies and methods have been followed to determine the flash floods on early basis so that evacuation announcements may be propagated. Numerous researches have been studied and carried out to accomplish this task. Development of dams and reservoirs have been given more significance. Artificial Intelligence based competent decision-making algorithms like Bayesian classifier, PSO, ANN, NNARX, SVM and GA have been applied to achieve more accuracy in predictive analysis. Direct observations from the sensors and data from the meteorological department have also been used for the predictive analysis of flash floods. Many yardstick parameters have been proposed in past researches to identify the flash floods vigorously like environmental CO2 levels, precipitation velocity, wind speed, upstream level, height of the water, pressure, temperature and cloud to ground flashes. In this research papers a novel Artificial Intelligence based approach Modified Cuckoo Search (MCS) has been adopted to forecast the flash floods more rapidly and accurately. Obtained results in the MATLAB have proved that Modified cuckoo search with the combination of Artificial Neural Network worked better than the recent available methods. Results have also been validated by comparing the MLP-PSO.

scholarly journals Decoupling of otolith and somatic growth during anadromous migration in a northern salmonid

2019 ◽  
Vol 76 (11) ◽  
pp. 1940-1953 ◽  
Author(s):  
Christie M. Morrison ◽  
Mélodie Kunegel-Lion ◽  
Colin P. Gallagher ◽  
Rick J. Wastle ◽  
Ellen V. Lea ◽  
...  
Keyword(s):  
Life History ◽  
Critical Time ◽  
Somatic Growth ◽  
Fish Growth ◽  
Calcium Deposition ◽  
Fish Length ◽  
Length Relationship ◽  
Anadromous Migration ◽  
Back Calculation ◽  
Size At Age

We assessed the fish length – otolith length relationship (FL–OL) in Dolly Varden (Salvelinus malma malma) to verify proportional growth. A decoupling was detected during first ocean migration where fish growth was occurring at a greater rate than otolith growth. Because of this decoupling, the application of traditional back-calculation models overestimated the size-at-age in premigratory char. We developed modified back-calculation equations from existing traditional models to account for this decoupling based on discontinuous piecewise regressions. The new biological intercept breakpoint method (BI–BP) provided the most accurate representation of fish size-at-age throughout all life history stages when compared with known size-at-capture values in fish. The decoupling indicates that factors other than somatic growth are important for otolith accretion. Physiological changes during smoltification likely alter calcium uptake and thereby affect calcium deposition rates on otoliths during this short but biologically critical time period of life history. It is probable that species exhibiting similar complex ontogenetic shifts in life history will likely exhibit decoupling to some extent in the FL–OL relationship.

The Organization of Traditional Inshore Fishery Management Systems in the Pacific

1989 ◽  
pp. 73-93 ◽  
Author(s):  
Kenneth Ruddle ◽  
Theodore Panayotou
Keyword(s):  
Fishery Management ◽  
Management Systems ◽  
The Pacific

scholarly journals A comparison of two surveys of invertebrates at Pacific Ocean islands: the giant clam at Raivavae Island, Australes Archipelago, French Polynesia

2009 ◽  
Vol 66 (9) ◽  
pp. 1825-1836 ◽  
Author(s):  
Serge Andréfouët ◽  
Kim Friedman ◽  
Antoine Gilbert ◽  
Georges Remoissenet
Keyword(s):  
Pacific Ocean ◽  
Fishery Management ◽  
Satellite Image ◽  
Standing Stock ◽  
French Polynesia ◽  
Giant Clam ◽  
Coverage Density ◽  
The Pacific ◽  
The Status ◽  
Ocean Islands

Abstract Andréfouët, S., Friedman, K., Gilbert, A., and Remoissenet, G. 2009. A comparison of two surveys of invertebrates at Pacific Ocean islands: the giant clam at Raivavae Island, Australes Archipelago, French Polynesia. – ICES Journal of Marine Science, 66: 1825–1836. An assessment of invertebrate fisheries is currently taking place at several Pacific Ocean islands. The objectives are to obtain either detailed information on certain stocks at limited sites or to assess more broadly a variety of benthic resources across different islands. In French Polynesia, giant clam (Tridacna maxima) populations were surveyed by Service de la Pêche and Institut de Recherche pour le Développement (SPE/IRD). Sampling was optimized to determine stock abundance as a tool to enhance management of the clam fishery. Currently, the Secretariat of the Pacific Community (SPC) is investigating throughout the Pacific the status of invertebrate resources; a large-scale study not necessarily establishing a precise stock estimate for resources such as clams, but comparing resource status for several target species using coverage, density, and size measures. Raivavae Island (French Polynesia) was investigated by both programmes and offered an opportunity to verify whether the different sampling schedules provided consistent perspectives of the status of the T. maxima resource. The different strategies that SPE/IRD and SPC adopted resulted in no direct spatial overlap between the locations investigated: nevertheless, the ranges of densities and clam sizes recorded were generally consistent between surveys, and both programmes described similar spatial variation in clam presence at an island scale. SPE/IRD provided a detailed map of clam densities per habitat using a high-resolution satellite image, which yielded an estimated standing stock of 8.16 ± 0.91 million clams, representing a flesh biomass of 354 ± 41 t. SPC's study delivered coverage, density, and clam length, but no stock estimate. Unavailable from SPE/IRD, SPC also described the status of a variety of important invertebrate species targeted by fishers in the Pacific. Both programmes independently made similar fishery management recommendations. The relative merits and complementarities of the two approaches in the context of Pacific Ocean Island resource management are discussed.

Annual variation in size-selective mortality of Atlantic salmon (Salmo salar) fry

2001 ◽  
Vol 58 (6) ◽  
pp. 1187-1195 ◽  
Author(s):  
S P Good ◽  
J J Dodson ◽  
M G Meekan ◽  
D AJ Ryan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Total Mortality ◽  
Weather Conditions ◽  
Fish Length ◽  
Selective Mortality ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Fry ◽  
Mean Size ◽  
The Mean

We investigated the size-selective mortality of Atlantic salmon (Salmo salar) fry during two consecutive summers that differed markedly in weather conditions. We sampled fry shortly after emergence in June and at the end of August to compare the distributions of back-calculated body size at hatching by examining otolith microstructure. Size-selective mortality was observed in both summers; however, the direction and strength of mortality differed. During the drought conditions of 1995, selective mortality was relatively weak and directed towards the smaller fry in the population. During the flood conditions of 1996, selective mortality was relatively strong and directed towards the larger fry of the same population. Interannual variability in size-selective mortality contributed to significant differences in the mean size of fry at the end of their first summer of life. Size-selective mortality rates estimated from the shifts in fish length at hatching observed during the first summer of life were comparable with published estimates of total mortality of Atlantic salmon fry, indicating that early mortality may be largely size selective. Mortality associated with hydroclimatic events can select against either small or large fish and is a key determinant of mean size attained by the end of the first summer of life.

Feeding Ecology of the Cockatiel, Nymphicus-Hollandicus, in a Grain-Growing Area

1987 ◽  
Vol 14 (1) ◽  
pp. 105 ◽  
Author(s):  
D Jones
Keyword(s):  
Feeding Ecology ◽  
Food Preferences ◽  
Direct Observations ◽  
South Wales ◽  
Nymphicus Hollandicus ◽  
Mean Size ◽  
Limited Food ◽  
Total Crop ◽  
The Mean ◽  
Important Food Item

The feeding ecology of the cockatiel Nymphicus hollandicus was studied in a grain-growing district near Moree, in northern New South Wales, between August 1980 and June 1982, by direct observations and monthly collections of birds in feeding flocks. Cockatiels fed from the ground, on fallen seed or by felling stems, and, when feeding on sorghum and sunflowers, while perched on the seed heads. The mean size of a feeding flock was 27; large flocks of more than 100 birds were formed only during periods of limited food supply. Cockatiels showed a clear preference for sorghum over sunflowers, and when on cereals they appeared to prefer softer, younger seed to harder, mature seed. Overall they fed on 29 seed types, including four grain-crops, 17 grasses and eight non-grass ground plants. Sorghum was by far the most important food item, making up almost 60% of total crop contents; sunflower made up only 6% of crop contents, and grasses 19.3%; 90% of this last was contributed by Phalarisparadoxa and Setar~a sp. Some management implications, based on apparent food preferences, are discussed.

Salmon Management and the Search for Values

1988 ◽  
Vol 45 (11) ◽  
pp. 2042-2050 ◽  
Author(s):  
Dennis L. Scarnecchia
Keyword(s):  
Pacific Northwest ◽  
Fishery Management ◽  
Management Plan ◽  
Human Values ◽  
Long Run ◽  
The Pacific ◽  
Salmon Management ◽  
Rational Management ◽  
Reliable Knowledge ◽  
Future Technologies

This perspective addresses the role of human values in North American salmon management. Salmon resources have been aided and harmed by technology, and managers must carefully assess how current and future technologies will be used to manage salmon. Effective managers must be knowledgeable of fishery science and human values. The science in fishery management is the objective, logical, and systematic method of obtaining reliable knowledge about fishery resources. The art in fishery management involves our values, that is, what we judge to be good, desirable, and important in the long run. A rational management plan is a selective embodiment of the values of the manager or of the organization or society that the manager represents. More surveys are needed to assess the values of the public toward salmon resources. Several potentially desirable directions are discussed for future salmon management in the Pacific Northwest.

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