Application of Rapid Appraisals of Fisheries Management System (RAFMS) to identify the seasonal variation of fishing ground locations and its corresponding fish species availability at Aceh waters, Indonesia

2018 ◽  
Vol 154 ◽  
pp. 46-54 ◽  
Author(s):  
Haekal A. Haridhi ◽  
Muhammad Nanda ◽  
Yudi Haditiar ◽  
Syamsul Rizal
Author(s):  
Mayara P. Neves ◽  
Pavel Kratina ◽  
Rosilene L. Delariva ◽  
J. Iwan Jones ◽  
Clarice B. Fialho

AbstractCoexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal variation in resource availability influences the consumption and assimilation of resources by two syntopic fish species, Psalidodon aff. gymnodontus and P. bifasciatus, in the Lower Iguaçu basin. We also tested the impact of seasonality on trophic niche breadth and diet overlap of these two dominant omnivores. Seasonal changes in resource availability strongly influenced the consumption and assimilation of resources by the two fish species. Both species exhibited high levels of omnivory, characterized by high diversity of allochthonous resources in the wet season. Terrestrial invertebrates were the main component of diet during this season. However, in the dry season, both species reduced their isotopic niches, indicating diet specialization. High diet overlap was observed in both seasons, but the isotopic niche overlap was smaller in the dry season. Substantial reduction in the isotopic niche of P. bifascistus and a shift toward aquatic invertebrates can facilitate coexistence during this season of resource shortage. Feeding plasticity allows omnivorous fish to adjust their trophic niches according to seasonality, promoting the exploitation of different resources during periods of greater resource diversity. This seasonal variation could be an important mechanism that contributes to the resource partitioning and coexistence of dominant omnivores in Neotropical streams.


2021 ◽  
Vol 324 ◽  
pp. 01007
Author(s):  
Yulius Yulius ◽  
Vaninda Aidina ◽  
Muhammad Ramdhan ◽  
August Daulat

The fishing ground is identical and closely related to chlorophyll-a abundance in the waters, associated with its fisheries potential. This research has been conducted to determine the concentration and distribution of chlorophyll-a in the seas, especially in the Fisheries Management Area (FMA) 712 encompassing the Java Sea. The analysis used monthly time-series data collected from the satellite imagery over the last 11 years, taken through the ERDDAP website. The mean concentration of chlorophyll-a in the study area was 1.13 mg/l in June 2013. Based on 11 years of data processing, it can be concluded that the highest concentration of chlorophyll-a occurred in the west monsoon season from November to April, where increased rainfall caused the nutrient wash from terrestrial to the open waters. The lowest chlorophyll-a concentration happened in the east monsoon season from April to November, where the dry season arrived. The existence of pelagic fishes in FMA 712, such as Sardinella Lemurs and Sardinella Fimbriata, in waters highly influenced by the chlorophyll-a concentration, while Thunnus Sp. and Exocoetidae Sp. not affected significantly to the existence of chlorophyll-a concentration and its distribution.


<em>Abstract.</em> —Radiometric aging of fishes is a recently developed technique using the disequilibria of <sup>210</sup> Pb:<sup>226</sup> Ra in calcified structures to determine age. It has been applied successfully to several fish species, but certain limitations have made improvements desirable. Because <sup>226</sup> Ra can be measured directly by counting atoms using isotope-dilution thermal ionization mass spectrometry (TIMS), a new ion-exchange separation technique was developed to isolate small quantities of radium from calcified structures for TIMS determination. The advantages of this new technique are reduced sample mass and processing time, and greater accuracy and precision of radium quantification. We applied this technique to calcified structures from three fish species: otolith cores of Pacific grenadier <em>Coryphaenoides acrolepis </em> and tarpon <em>Megalops atlanticus, </em> and pectoral fin ray cores of Atlantic sturgeon <em>Acipenser oxyrinchus. </em> Annulus-derived age estimates for <em>C. acrolepis </em> were accurate with a confirmed longevity of at least 48 years. Although annulus-derived ages for <em>M. atlanticus </em> were inconsistent with radiometric ages, radiometric aging confirmed that tarpon are longlived; females may exceed 82 years. Radiometric age could not be determined for <em>A. oxyrinchus </em> because <sup>210</sup> Pb activities were greater than could be supported by ingrowth from <sup>226</sup> Ra decay. In this paper we discuss the application and limitations of this technique and its relevance to fisheries management.


2018 ◽  
Vol 16 (2) ◽  
Author(s):  
César A. Bonilla-Castillo ◽  
Edwin Agudelo Córdoba ◽  
Guber Gómez ◽  
Fabrice Duponchelle

ABSTRACT The black prochilodus (Prochilodus nigricans) is one of the most landed scaled fish species of the middle and upper parts of the Putumayo River, in the tri-national area between Colombia, Ecuador and Peru. Despite its importance, biological information about this species is too scant to guide fisheries management in this portion of the Colombian Amazon. In this study, 10884 individuals were sampled in the fish markets of Puerto Leguízamo between 2009 and 2017. This sampling was used to document reproductive patterns, but also growth and mortality parameters from length frequency distributions. The size at which all fish were mature was 22 cm Ls, which should be the established as the minimum size of capture to ensure that all fish have had a chance to reproduce before being caught. Growth and mortality parameters indicated a slower growth in the Putumayo than in other Amazonian rivers and a relatively high exploitation rate.


Author(s):  
Vu Ngoc Ut ◽  
Au Van Hoa ◽  
Huynh Phuoc Vinh

Fish biodiversity on Hau (Bassac) river was investigated to assess the status of species composition and fishing by fishing gears during a year. Sampling was implemented monthly at the upper part (An Giang province), middle part (Can Tho City) and lower part (Soc Trang province) of Hau River using trawl net as main sampling gear. Additionally, fish composition was also recorded from four other most popular fishing gears including cast net, gill net, fixed net and hook operated in the study sites. Fish species composition was determined by fishing gears and their abundance (CPUE) was calculated only from the main sampling gear (trawl net). The results showed that a total of 176 fish species belonging to 16 orders and 49 families was recorded. Perciformes was the most abundant group with 51 species followed by Cypriniformes with 46 species. The number of fish species was decreasing from upper part to lower part. Trawl net was considered the most destructive gear as up to 145 fish species caught by this device, followed by gill net with 98 species, fixed net 75, cast net 57, and hooks 16 species. CPUE was very low ranging from  0.53 kg.ha−1 h−1 to 26.30 kg.ha−1 h−1. Higher CPUE was recorded at lower part in compared to upper part and middle part, and at dry season in compared to rainy season. Regulation on fishing gears, fishing ground and season should be taken into consideration to protect and conserve the resources.


2015 ◽  
Vol 27 (4) ◽  
pp. 333-340 ◽  
Author(s):  
Stuart Hanchet ◽  
Keith Sainsbury ◽  
Doug Butterworth ◽  
Chris Darby ◽  
Viacheslav Bizikov ◽  
...  

AbstractSeveral recent papers have criticized the scientific robustness of the fisheries management system used by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), including that for Ross Sea toothfish. Here we present a response from the wider CCAMLR community to address concerns and to correct some apparent misconceptions about how CCAMLR acts to promote conservation whilst allowing safe exploitation in all of its fisheries. A key aspect of CCAMLR’s approach is its adaptive feedback nature; regular monitoring and analysis allows for adjustments to be made, as necessary, to provide a robust management system despite the statistical uncertainties inherent in any single assessment. Within the Ross Sea, application of CCAMLR’s precautionary approach has allowed the toothfish fishery to develop in a steady fashion with an associated accumulation of data and greater scientific understanding. Regular stock assessments of the fishery have been carried out since 2005, and the 2013 stock assessment estimated current spawning stock biomass to be at 75% of the pre-exploitation level. There will always be additional uncertainties which need to be addressed, but where information is lacking the CCAMLR approach to management ensures exploitation rates are at a level commensurate with a precautionary approach.


2014 ◽  
Vol 86 (1) ◽  
pp. 383-406 ◽  
Author(s):  
JÚLIO C. SÁ-OLIVEIRA ◽  
RONALDO ANGELINI ◽  
VICTORIA J. ISAAC-NAHUM

We investigated the niche breadth and overlap of the fish species occurring in four environments affected by the Coaracy Nunes reservoir, in the Amapá Brazilian State. Seasonal samples of fishes were taken using a standard configuration of gillnets, as well as dragnets, lines, and castnets. Five hundred and forty stomach contents, representing 47 fish species were analyzed and quantified. Niche breadth and overlap were estimated using indexes of Levins and Pianka, respectively, while interspecific competition was evaluated using a null model (RA3). ANOVA and the KruskalWallis test were used, respectively, to evaluate differences in niche breadth and overlap between areas. The data indicate that the majority of the fish species belong to the piscivore, omnivore, and detritivore guilds. These species have likely colonized the environments due to the availability of suitable feeding resources, and the favorable physical conditions created by the river damming. Overall, few species have ample niches, but most of them are highly specialized. Resources seasonal variation had little effect on the feeding behavior of most species in the study areas. The null models indicated that competition was not a factor determining on community structure.


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