scholarly journals Patterns of courtship acoustics and geophysical features at spawning sites of black grouper (Mycteroperca bonaci)

2017 ◽  
Vol 115 (2) ◽  
pp. 186-195 ◽  
Author(s):  
Phillip J. Sanchez ◽  
Richard S. Appeldoorn ◽  
Michelle T. Schärer-Umpierre ◽  
James V. Locascio
Keyword(s):  
Mycteroperca Bonaci ◽  
Spawning Sites ◽  
Geophysical Features

scholarly journals Balanced harvesting in fisheries: a preliminary analysis of management implications‡

2015 ◽  
Vol 73 (6) ◽  
pp. 1668-1678 ◽  
Author(s):  
S. M. Garcia ◽  
J. Rice ◽  
A. Charles
Keyword(s):  
Fisheries Management ◽  
Preliminary Analysis ◽  
Fishery Management ◽  
Sustainable Use ◽  
Relative Size ◽  
Implementation Challenges ◽  
Multispecies Fisheries ◽  
Natural Productivity ◽  
Partial Implementation ◽  
Spawning Sites

Abstract Balanced harvest (BH) proposes to distribute a moderate mortality from fishing across the widest possible range of species, stocks, and sizes in an ecosystem, in proportion to their natural productivity so that the relative size and species composition are maintained, in line with the CBD requirement for sustainable use. This proposal has many and not always intuitive implications for fisheries management, e.g. in relation to selectivity, protection of juveniles and spawning sites, models of harvesting strategies, a focus on size and species, the impacts of discarding, aspects of emblematic species and ecosystem services, operational complexity, partial implementation, ecosystem rebuilding, and relations with broader management frameworks. The paper closes with a discussion of BH implementation, concluding that a logical step would be to integrate several separate initiatives to move fisheries into a more ecosystem-conscious context. Implementation challenges will be encountered, but there are lessons to be drawn from fishery ecosystems already close to BH, as in some tropical multispecies fisheries, and further, the implementation challenges are already being taken on in many well-managed fisheries and areas as management begins to address the realities of what ecosystem-based fishery management actually entails.

Backscattering and geophysical features of volcanic ridges offshore Santa Rosalia, Baja California Sur, Gulf of California, Mexico

1999 ◽  
Vol 93 (1-2) ◽  
pp. 75-92 ◽  
Author(s):  
Hubert Fabriol ◽  
Luis A Delgado-Argote ◽  
Juan José Dañobeitia ◽  
Diego Córdoba ◽  
Antonio González ◽  
...  
Keyword(s):  
Gulf Of California ◽  
Baja California ◽  
Baja California Sur ◽  
Santa Rosalia ◽  
Geophysical Features

Is it possible to predict habitat use by spawning salmonids? A test using California golden trout (Oncorhynchus mykiss aguabonita)

1999 ◽  
Vol 56 (9) ◽  
pp. 1576-1584 ◽  
Author(s):  
Roland A Knapp ◽  
Haiganoush K Preisler
Keyword(s):  
Oncorhynchus Mykiss ◽  
Water Depth ◽  
Parametric Model ◽  
Water Velocity ◽  
Habitat Characteristics ◽  
Nonparametric Model ◽  
Habitat Features ◽  
Substrate Size ◽  
Depth Water ◽  
Spawning Sites

It is widely believed that stream salmonids select spawning sites based on water depth, water velocity, and substrate size. Attempts to predict spawning locations using these habitat features have met with little success, however. In this study, we used nonparametric logistic regression to determine what habitat features were associated with the locations chosen by spawning California golden trout (Oncorhynchus mykiss aguabonita). From this nonparametric model, we developed a parametric model that incorporated the habitat features most strongly associated with spawning sites and used this model to calculate the probability of use by spawning golden trout for specific stream locations. The overall nonparametric model was highly significant and explained 62% of the variation in spawning location. Four of the eight habitat variables, substrate size, water depth, water velocity, and stream width, had highly significant effects and alone explained 59% of the variation in spawning location. The results of a cross-validation procedure indicated that the parametric model generally provided a good fit to the data. These results indicate that location-specific probabilities of use were predictable based on easily measured habitat characteristics and that nonparametric regression, an approach still rarely used in ecological studies, may have considerable utility in the development of fish-habitat models. Given the escalating pace at which fish habitats are being altered, such models are increasingly important in predicting the effects of these alterations on populations.

scholarly journals Distribuição e abundância de peixes bentônicos explotados pelos linheiros ao largo do sudeste do Brasil (1986-1995)

1998 ◽  
Vol 58 (4) ◽  
pp. 619-632 ◽  
Author(s):  
M. P. PAIVA ◽  
M. F. ANDRADE-TUBINO
Keyword(s):  
Mycteroperca Bonaci ◽  
Cabo Frio

Este trabalho trata da distribuição e abundância das principais espécies de peixes bentônicos explotados pelos linheiros ao largo do sudeste do Brasil (latitudes 18º-26ºS), no período 1986-1995, listadas a seguir, com as respectivas participações no total das capturas: batata = Lopholatilus vilariii Ribeiro = 33,4%, namorado = Pseudopercis numida Ribeiro = 18,4%, cherne = Epinephelus niveatus (Valenciennes) = 12,1%, garoupa = Epinephelus marginatus (Lowe) = 4,1% e badejo = Mycteroperca bonaci (Poey) = 3,1%. As pescarias ocorreram em águas tropicais (latitudes 18º- 23ºS) e subtropicais (latitudes 23º-26ºS), tendo como divisor zoogeográfico a ressurgência de Cabo Frio. Os dados foram agrupados por faixas de latitude e de profundidade, segundo espécies e estações do ano. As pescarias estiveram grandemente concentradas nas águas subtropicais, com tendência(s) de produtividade decrescente, à medida que aumenta(m) a latitude e/ou a profundidade dos pesqueiros explotados. Nas águas tropicais, as espécies dominantes foram a garoupa e o badejo, de forma indiscutível entre as latitudes 18º-20ºS, com maiores capturas em profundidades de até 80 metros. Nas águas subtropicais, as espécies dominantes sempre foram o batata, o namorado e o cherne, com maiores capturas em profundidades superiores a 100 metros, incluindo a parte superior do talude continental. A produção das cinco espécies principais apresentou tendências de variação estacional, mas apenas o cherne evidenciou deslocamento sazonal ao longo da costa. Foram comprovadas a menor diversidade e a maior biomassa de peixes bentônicos nas águas subtropicais.

scholarly journals Investigation of Geology and Hydro-geophysical Features Using Electromagnetic and Vertical Sounding Methods for Abu Zabad Area, Western Kordofan State, Sudan

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Ahmed Babeker Elhag
Keyword(s):  
Geophysical Methods ◽  
Structural Features ◽  
Groundwater Potential ◽  
Crystalline Basement ◽  
Metamorphic Rocks ◽  
Basement Rock ◽  
Basement Complex ◽  
Groundwater Aquifers ◽  
Electrical Sounding ◽  
Geophysical Features

The geology and hydro-geophysical features can aid in identifying borehole location. The study aims to investigate groundwater aquifers and best location of boreholes in the crystalline basement area of Abu Zabad near El Obeid Southwest, Sudan. The study area is underlain by two aquifers formations from Precambrian age. The oldest units of basement complex of area under investigation consist of metamorphic rocks including gneiss, schist, and quartzite.The geophysical methods electromagnetic (EM) and vertical electrical sounding (VES) surveys showed that best aquifers yield for construction of boreholes are in weathering and fractures formation. The EM results revealed that structural features are significant for groundwater potential and interpretation of the VES data also revealed four geo-electric layers, but generally two distinct lithologic layers, which include Superficial deposit and bedrock-basement respectively. The curves generated from the data revealed H curve and HK curve, and thickness of these layers varies from 15 m to 50 m in the area. The aquifer thickness range from 20 m to 30 m. The study concludes that these techniques are suitable for identifying borehole location in the basement rock in Abu Zabad Area Sudan.

scholarly journals Variation in Population Structures of Tropical Freshwater Eels, Anguilla Marmorata, A. Bicolor Bicolor and A. Bengalensis Bengalensis, in the Indo-Pacific

2021 ◽  
Author(s):  
Takaomi Arai ◽  
Hussein Taha
Keyword(s):  
Tropical Species ◽  
Pacific Region ◽  
Oceanic Current ◽  
Dispersion Patterns ◽  
Population Structures ◽  
Different Populations ◽  
And Migration ◽  
Current Systems ◽  
Freshwater Eels ◽  
Spawning Sites

Abstract Freshwater eels, genus Anguilla, have a distinctive catadromous life history, which could be associated with certain oceanic current systems and offshore spawning sites. Thus, migration and dispersion patterns are believed to be important factors influencing the population structures of each species. Temperate eel species are well studied, while little research has been conducted on the tropical counterparts that comprise two-thirds of all eel species. The population structures of three tropical species, A. marmorata, A. bicolor bicolor and A. bengalensis bengalensis, which are distributed widely in the Indo-Pacific region, were explored by means of DNA sequence analysis of mitochondrial cytochrome c oxidase subunit I (COI). This study found that A. bicolor bicolor had two genetically distinct populations, and these different populations co-occur geographically in the Indo-Pacific region, while A. marmorata and A. bengalensis bengalensis showed a panmictic-population structure in this region. The populations of A. bicolor bicolor were also found to have lower genetic variability than the populations of A. marmorata and A. bengalensis bengalensis. This study is the first to explore the population genetic structure of A. bengalensis bengalensis. The present results also suggest plausible dispersion and migration of these tropical species into their continental habitats.

scholarly journals Inventaire spécifique et caractéristiques de quelques frayères du lac de Buyo dans le Parc National de Taï (Sud-Ouest Côte d’Ivoire)

2020 ◽  
Vol 145 ◽  
pp. 14902-14913
Author(s):  
N’DRI Olga Rosemonde ◽  
KONAN Yao Aristide ◽  
MONNEY Attoubé Ida ◽  
KONE Tidiani
Keyword(s):  
Cote D'ivoire ◽  
National Park ◽  
Sexual Maturity ◽  
Côte D’Ivoire ◽  
Cote D’Ivoire ◽  
Taï National Park ◽  
Côte D'ivoire ◽  
Spawning Areas ◽  
Tai National Park ◽  
Spawning Sites

Objectifs : Des investigations ont été menées dans 11 sites du lac de Buyo situés sur le cours du fleuve Sassandra dans le Parc National de Taï (Côte d’Ivoire) en vue de connaître les espèces de poisson qui utilisent ces zones comme sites de reproduction. Méthodologie et Résultats : Dans chaque site d’échantillonnage, les variables environnementales ont été mesurées et les poissons ont été capturés à l’aide de filets maillants. Les stades de maturité sexuelle avancés ont été considérés comme critères de reconnaissance des sites de fraie. La richesse spécifique a été de 32 espèces, répartie en 13 familles et dominée par les Cichlidae (7 espèces, soit 22%). Sur la base des stades sexuels de maturité, 14 espèces, en phase de reproduction, ont été capturées dans les 11 sites d’échantillonnage. Les résultats de l’analyse des sédiments ont indiqué une prédominance de sable (>60%) dans les sites de reproduction et des valeurs optimales de température (28,52°C), de pH (6,53), de conductivité (36,50 μS/cm) et d’oxygène dissous (5,37 mg/l). Conclusion et application des résultats : La présente étude a montré que les sites échantillonnés dans le lac de Buyo situé à l’intérieur du le Parc National de Taï sont caractérisés par des sédiments sableux et constituent des frayères pour plusieurs espèces de poisson. La localisation de ces zones de reproduction représente donc un outil important pour les gestionnaires dans la conservation de la diversité piscicole du parc national de Taï. Mots clés : sites de frai, stade de maturité sexuelle, ichtyofaune, lac de barrage de Buyo. Specific inventory and characteristics of some spawning grounds of Lake Buyo in the Taï National Park (South-West Côte d'Ivoire) Abstract Objectives: Investigations were carried out in 11 sites of Lake Buyo located in the midstream of Sassandra River in Taï National Park (Côte d'Ivoire) to get to know fish species that use these areas as spawning sites. Methodology and Results: Environmental variables were measured in each sampling sites and fish were caught using gillnets. Advanced stages of sexual maturity were considered as recognition criteria of spawning areas. Specific richness was of 32 species, belonging in 13 families and dominated by Cichlidae (7 species, 22%). Based on advanced sexual maturity stages, 14 species in spawning period, were captured at the 11 sampling sites. Results of sediment analysis indicated a predominance of sand (> 60%) in spawning sites and optimal values of temperature (28.52°C), pH (6,53), conductivity (36,50 μS/cm) and dissolved oxygen (5,37 mg/l). Conclusion and application of results: The present study showed that sites sampled in Lake Buyo located within the Tai National Park are characterized by sandy sediments and constitute spawning areas for several fish species. The location of these spawning areas therefore is an important tool for managers in conserving fish diversity of Taï National Park. Keywords: spawning sites, stage of sexual maturity, Ichtyofauna, Buyo Dam Lake.

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