scholarly journals Analysis of habitat characteristics of small pelagic fish based on generalized additive models in Kepulauan Seribu Waters

2018 ◽  
Vol 139 ◽  
pp. 012014 ◽  
Author(s):  
A A Rivai ◽  
V P Siregar ◽  
S B Agus ◽  
H Yasuma
Keyword(s):  
Generalized Additive Models ◽  
Pelagic Fish ◽  
Additive Models ◽  
Habitat Characteristics ◽  
Small Pelagic Fish

Oceanographic Conditions on Small Pelagic Fishery in the Gulf of Bone Waters

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Safruddin Safruddin ◽  
Rachmat Hidayat ◽  
Mukti Zainuddin
Keyword(s):  
Chlorophyll A ◽  
Generalized Additive Models ◽  
Pelagic Fish ◽  
Additive Models ◽  
Fish Distribution ◽  
Fishing Ground ◽  
Small Pelagic Fish ◽  
The Relationship ◽  
Pelagic Fishery ◽  
Oceanographic Conditions

This study aimed to investigate the relationship between the dinamic oceanographic condition and fluctuation in the catch of small pelagic fish. Study on the dinamic oceanographic conditions were focused on the sea surface temperature (SST), chlorophyll-a concentration (SSC) and water depth. The study took place in the area of Gulf of Bone located, data collection was started from April to September 2017. The data were collected using experimental fishing metode (large liftnet) and applications of remote sensing in satellite oceanography, which then analysed using Geographic Information System (GIS) dan Generalized Additive Models (GAMs). The result showed that the distribution of small pelagic fish tends to be within the area of temperature ranging from 29.5 to 30.0oC, the chlorophyll-a from 0.7 to 0.9 mg.m-3 and concentrated within the coastal area with in waters depth maximum of 100 m.Keywords: Oceanography, small pelagic fish, distribution, fishing ground, Gulf of Bone

scholarly journals Changes in Life History Traits of Small Pelagic Fish in the Western Mediterranean Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Marta Albo-Puigserver ◽  
Maria Grazia Pennino ◽  
Jose María Bellido ◽  
Ana Isabel Colmenero ◽  
Ana Giráldez ◽  
...  
Keyword(s):  
Life History ◽  
Mediterranean Sea ◽  
Body Condition ◽  
Life History Traits ◽  
Seawater Temperature ◽  
Western Mediterranean ◽  
Pelagic Fish ◽  
Additive Models ◽  
Small Pelagic Fish ◽  
Western Mediterranean Sea

Small pelagic fish (SPF) in the western Mediterranean Sea are key elements of the marine food web and are important in terms of biomass and fisheries catches. Significant declines in biomass, landings, and changes in the age/size structure of sardine Sardina pilchardus and anchovy Engraulis encrasicolus have been observed in recent decades, particularly in the northern area of the western Mediterranean Sea. To understand the different patterns observed in SPF populations, we analyzed key life history traits [total length at age, length at maturity, gonadosomatic index (GSI), and body condition (Kn)] of sardine and anchovy collected between 2003 and 2017, from different fishing harbors distributed along a latitudinal gradient from northern to southern Spain. We used Generalized Linear Models (GLM) to estimate the length at maturity and Generalized Additive Models (GAMs) to test the relationship with environmental variables (seawater temperature, water currents, and net primary productivity). The life history traits of both species presented seasonal, interannual and latitudinal differences with a clear decline in length at age, length at first maturity, and body condition, for both species in the northern part of the study area. In the southern part, on the contrary, life history traits did not present a clear temporal trend. The environmental conditions partially explained the long-term changes in life history traits, but the selected variables differed between areas, highlighting the importance of regional oceanographic conditions to understand the dynamics of small pelagic fish. The truncated length-at-age pattern for both species with the disappearance of the larger individuals of the population could have contributed to the poor condition of small pelagic fish populations in the northern part of the western Mediterranean Sea in recent years. In the south area, recent declines in body condition for sardine and anchovy were observed and could be a possible first sign for future population declines. This study highlights the importance of understanding the trade-off between the energy invested in reproduction, maintenance and growth at seasonal and interannual level to advance our knowledge on how environmental and human pressures influence population dynamics of small pelagic fish at local and regional scales.

scholarly journals Krill space: a comparative assessment of mesoscale structuring in polar and temperate marine ecosystems

2012 ◽  
Vol 69 (7) ◽  
pp. 1317-1327 ◽  
Author(s):  
Jarrod A. Santora ◽  
William J. Sydeman ◽  
Isaac D. Schroeder ◽  
Christian S. Reiss ◽  
Brian K. Wells ◽  
...  
Keyword(s):  
Spatial Organization ◽  
Generalized Additive Models ◽  
Marine Ecosystems ◽  
Comparative Assessment ◽  
Habitat Associations ◽  
Shelf Break ◽  
Additive Models ◽  
Reference Points ◽  
Habitat Characteristics ◽  
Chl A

Abstract Santora, J. A., Sydeman, W. J., Schroeder, I. D., Reiss, C. S., Wells, B. K., Field, J. C, Cossio, A. M., and Loeb, V. J. 2012. Krill space: a comparative assessment of mesoscale structuring in polar and temperate marine ecosystems. – ICES Journal of Marine Science, 69: . The spatial organization, mesoscale variability, and habitat associations of krill within portions of the Antarctic Peninsula and California Current marine ecosystems are compared. Using a decade of acoustic observations and remotely sensed oceanography (2000–2009), the hypothesis that mesoscale spatial organization of krill in both systems closely relates to geospatial variability of the shelf break and is non-linearly related to geostrophic flow and positively related to chlorophyll a (Chl a) is tested. Directional-dependence analysis to measure spatial variability of krill is used along with spatially explicit generalized additive models to quantify and compare the spatial relationships among krill and habitat characteristics in both systems. The results suggest the following aspects of krill spatial organization: (i) areas of dense aggregation, i.e. hot spots, are present in both systems and are orientated in the direction of the shelf break, (ii) moderate levels of eddy kinetic energy seem to concentrate krill in favourable habitats and lessen the likelihood of advection away from the system, and (iii) variable responses to surface Chl a concentration suggest that real-time Chl a values may not be useful as a global predictor of important krill habitat. The results provide valuable reference points for marine spatial management of krill and for refining ecosystem and foodweb models.

scholarly journals Characterisation of season-wise spatial distribution of small pelagic fishery in Kerala, south-west coast of India

2019 ◽  
Vol 66 (4) ◽  
Author(s):  
P.H. Dhiju Das ◽  
C.G. Joshy ◽  
Leela Edwin
Keyword(s):  
Pelagic Fish ◽  
Additive Models ◽  
Fish Abundance ◽  
Fishing Ground ◽  
Small Pelagic Fish ◽  
Geostatistical Methods ◽  
South West Coast ◽  
Spatial Parameters ◽  
Pelagic Fishing ◽  
Pelagic Fishery

In this study, we attempted to identify and characterise the spatial variability of small pelagic fish abundance using geostatistical methods. The small pelagic fish abundance was estimated in terms of spatial parameters using generalised additive models (GAMs). The ring seine fishing grounds in the south-eastern Arabian Sea exhibited seasonal variability in distribution. Results of the study would help in prediction of the major pelagic fishing grounds for traditional fishers which would help in reducing fuel and time spent on searching for the fishing ground leading to sustainable exploitation. The prediction model can contribute to the management of pelagic fishery along the Kerala coast.

The box-balance model: a new tool to assess fish larval survival, applied to field data on two small pelagic fish

2020 ◽  
Vol 650 ◽  
pp. 289-308 ◽  
Author(s):  
V Raya ◽  
J Salat ◽  
A Sabatés
Keyword(s):  
Field Data ◽  
Fish Larvae ◽  
Larval Growth ◽  
Warming Trend ◽  
Mortality Rates ◽  
Larval Survival ◽  
Pelagic Fish ◽  
Balance Model ◽  
Small Pelagic Fish ◽  
Mesoscale Structures

This work develops a new method, the box-balance model (BBM), to assess the role of hydrodynamic structures in the survival of fish larvae. The BBM was applied in the northwest Mediterranean to field data, on 2 small pelagic fish species whose larvae coexist in summer: Engraulis encrasicolus, a dominant species, and Sardinella aurita, which is expanding northwards in relation to sea warming. The BBM allows one to quantify the contribution of circulation, with significant mesoscale activity, to the survival of fish larvae, clearly separating the effect of transport from biological factors. It is based on comparing the larval abundances at age found in local target areas, associated with the mesoscale structures (boxes), to those predicted by the overall mortality rate of the population in the region. The application of the BBM reveals that dispersion/retention by hydrodynamic structures favours the survival of E. encrasicolus larvae. In addition, since larval growth and mortality rates of the species are required parameters for application of the BBM, we present their estimates for S. aurita in the region for the first time. Although growth and mortality rates found for S. aurita are both higher than for E. encrasicolus, their combined effect confers a lower survival to S. aurita larvae. Thus, although the warming trend in the region would contribute to the expansion of the fast-growing species S. aurita, we can confirm that E. encrasicolus is well established, with a better adapted survival strategy.

Small pelagic fish responses to fine-scale oceanographic conditions: implications for the endangered African penguin

2017 ◽  
Vol 569 ◽  
pp. 187-203 ◽  
Author(s):  
AM McInnes ◽  
PG Ryan ◽  
M Lacerda ◽  
J Deshayes ◽  
WS Goschen ◽  
...  
Keyword(s):  
Pelagic Fish ◽  
Fine Scale ◽  
Small Pelagic Fish ◽  
African Penguin ◽  
Oceanographic Conditions

PEMETAAN RANTAI NILAI IKAN PELAGIS KECIL DI KOTA AMBON

2018 ◽  
Vol 2 (1) ◽  
pp. 15-21
Author(s):  
Yolanda MTN Apituley ◽  
Dionisius Bawole ◽  
Imelda KE Savitri ◽  
Friesland Tuapettel
Keyword(s):  
Value Chain ◽  
Secondary Data ◽  
Pelagic Fish ◽  
Value Chain Analysis ◽  
Small Pelagic Fish ◽  
Fresh Fish ◽  
Chain Analysis ◽  
The Government ◽  
Market Distance ◽  
Role Of The Government

This research was taken in Ambon (Latuhalat and Laha) and in Central Maluku Regency (Waai) in May – July 2018. It was aimed at mapping the value chain of small pelagic fish in Ambon through: 1) mapping of product, financial and information flows and 2). analysis of percentage distribution of small pelagic fish caught. The data used in this study was primary and secondary data, and analyzed by using value chain analysis. The results show that small pelagic fish marketing chain in Ambon consisted of six models with five actors. Each chain is formed due to the conditions and situation of market, resulted by the influencing of catches of fishermen and traders' capital. The broker plays an important role in marketing small pelagic fish in the market and obtaining 10% of the fishermen's catch that can be distributed, both to retailers and cold storage. Fish caught by the fishermen is still fresh in general when arrives in the consumers, because the fishing area is not too far, the market distance with the production centers is also quite close and in general fishermen and traders have understood the importance of maintaining product quality. Even so, the role of the Government in providing marketing facilities and infrastructure is needed so that modern market conditions can be applied in marketing fresh fish in Ambon.

scholarly journals Predicting Malaria Transmission Dynamics in Dangassa, Mali: A Novel Approach Using Functional Generalized Additive Models

2020 ◽  
Vol 17 (17) ◽  
pp. 6339
Author(s):  
François Freddy Ateba ◽  
Manuel Febrero-Bande ◽  
Issaka Sagara ◽  
Nafomon Sogoba ◽  
Mahamoudou Touré ◽  
...  
Keyword(s):  
Wind Speed ◽  
Malaria Incidence ◽  
Generalized Additive Models ◽  
Community Health Center ◽  
Additive Model ◽  
Additive Models ◽  
Functional Regression ◽  
Novel Approach ◽  
Malaria Incidence Rate ◽  
Mean Wind Speed

Mali aims to reach the pre-elimination stage of malaria by the next decade. This study used functional regression models to predict the incidence of malaria as a function of past meteorological patterns to better prevent and to act proactively against impending malaria outbreaks. All data were collected over a five-year period (2012–2017) from 1400 persons who sought treatment at Dangassa’s community health center. Rainfall, temperature, humidity, and wind speed variables were collected. Functional Generalized Spectral Additive Model (FGSAM), Functional Generalized Linear Model (FGLM), and Functional Generalized Kernel Additive Model (FGKAM) were used to predict malaria incidence as a function of the pattern of meteorological indicators over a continuum of the 18 weeks preceding the week of interest. Their respective outcomes were compared in terms of predictive abilities. The results showed that (1) the highest malaria incidence rate occurred in the village 10 to 12 weeks after we observed a pattern of air humidity levels >65%, combined with two or more consecutive rain episodes and a mean wind speed <1.8 m/s; (2) among the three models, the FGLM obtained the best results in terms of prediction; and (3) FGSAM was shown to be a good compromise between FGLM and FGKAM in terms of flexibility and simplicity. The models showed that some meteorological conditions may provide a basis for detection of future outbreaks of malaria. The models developed in this paper are useful for implementing preventive strategies using past meteorological and past malaria incidence.

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