scholarly journals Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3391
Author(s):  
Arne N. Linløkken
Keyword(s):  
Body Size ◽  
Fish Species ◽  
Pelagic Fish ◽  
Fish Density ◽  
Present Species ◽  
Fish Stock ◽  
Small Fish ◽  
Large Species ◽  
Lake Productivity ◽  
Oligotrophic Lakes

Density estimation of pelagic fish was performed by means of single beam echosounding in 17 lakes within a period of 34 years, from 1985 to 2018. Surveys were performed repeatedly (two to fourteen times) in five lakes. The density estimates ranged from 34 to 4720 fish/ha and were significantly correlated with total phosphorus concentration. The high density in relatively phosphorus rich lakes (TP > 10 µg/L) was comprised of small fish (<20 cm) and was partly due to the higher number of pelagic fish species. The number of pelagic species varied from one, Arctic charr, in the most elevated and oligotrophic lakes, and whitefish dominated in less elevated oligotrophic lakes. In lowland lakes characterized as mesotrophic or tending to mesotrophy, smelt, vendace, and two to three cyprinids comprised the pelagic fish stock. These fish species predate zooplankton effectively, and species composition and body size of planktonic cladocerans was affected by fish density. Large species of Daphnia were lacking in lakes with high fish density, and body size of present species, D. galeata, D. cristata, and Bosmina spp. were negatively correlated with pelagic fish density.

scholarly journals Assessing the Fish Stock Status in Lake Trichonis: A Hydroacoustic Approach

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1823
Author(s):  
Triantafyllia-Maria Perivolioti ◽  
Jaroslava Frouzova ◽  
Michal Tušer ◽  
Dimitra Bobori
Keyword(s):  
Sustainable Management ◽  
Pelagic Fish ◽  
Fish Density ◽  
Current Status ◽  
Fish Stock ◽  
Fish Length ◽  
Eastern Region ◽  
Inland Water ◽  
Intermediate Layers ◽  
Water Ecosystems

Fish stock monitoring is an important element for the sustainable management of inland water resources. A scarcity of data and the lack of systematic monitoring for Lake Trichonis precludes an up-to-date assessment. To assess the current status of pelagic fish stock, a hydroacousting survey was conducted for the first time in Lake Trichonis, Greece. In October 2019, the lake was acoustically surveyed with two, horizontally and vertically mounted, 120 kHz transducers during day and night. A decreasing gradient in pelagic fish density from the western to the eastern shores of the lake was observed. Fish density was significantly higher in the intermediate layers of the water column, in the eastern region, compared to the western region. The lake appears to host primarily communities of small-sized fish (TL: 0–5 cm), whereas larger fish (TL: 5–50 cm) are a small minority of the total fish stock. The overall average estimated fish length was approximately 2.4 cm. The adoption of routine inland fish stock monitoring through hydroacoustic methods could be a promising step in the effort to improve the understanding of unique inland water ecosystems with minimum impact on endemic species, as well as to mitigate human impact and achieve long-term sustainable management.

scholarly journals Short Communication: The species and body size composition of pelagic fishes that caught by troll line in the fish landing of Sendang Biru, East Java, Indonesia

2019 ◽  
Vol 20 (6) ◽  
Author(s):  
DEWI HIDAYATI ◽  
BUGGIE OCLANDHI ◽  
NOVA MAULIDINIA ◽  
NOOR NAILIS SA’ADAH ◽  
AWIK PUJI DYAH NURHAYATI
Keyword(s):  
Body Size ◽  
Fish Species ◽  
Short Communication ◽  
Size Composition ◽  
Pelagic Fish ◽  
Yellowfin Tuna ◽  
The Body ◽  
Skipjack Tuna ◽  
Pelagic Fishes ◽  
Fish Samples

Abstract. Hidayati D, Oclandhi B, Maulidinia N, Sa’adah NN, Nurhayati APD. 2019. Short Communication: The species and body size composition of pelagic fishes that caught by troll line in the fish landing of Sendang Biru, East Java, Indonesia. Biodiversitas 20: 1764-1769. Troll line is the most used pelagic fishing gear for fishermen in Sendang Biru, the part of Indian ocean at East Java, which have an impact on the catch composition. The study was aimed to obtain data on species composition and size of pelagic fish caught in troll line in Sendang Biru, East Java, Indonesia. Fish samples were collected from nine different vessels landed in Sendang Biru for three days in April 2018. The composition of fish species was measured based on relative abundance. The fish size composition was obtained by measuring fork length which is also used to determine the stage of development of juvenile (Jv) or adult (Ad) fish. The results of the research showed there were four pelagic fish species which dominated by Katsuwonus pelamis or skipjack tuna (50.05%) and Thunnus albacares or yellowfin tuna (47.95%) and a small amount of Coryphaena hippurus and Makaira mazara. According to the body size, the fish caught by troll line in Sendang Biru is dominated by adult skipjack tuna (41-60 cm) and juvenile yellowfin tuna (21-78 cm).

scholarly journals Density-dependent effects as key drivers of intraspecific size structure of six abundant fish species in lakes across Europe

2016 ◽  
Vol 73 (4) ◽  
pp. 519-534 ◽  
Author(s):  
Ignasi Arranz ◽  
Thomas Mehner ◽  
Lluís Benejam ◽  
Christine Argillier ◽  
Kerstin Holmgren ◽  
...  
Keyword(s):  
Body Size ◽  
Density Dependence ◽  
Fish Species ◽  
Size Structure ◽  
Catch Per Unit Effort ◽  
Lake Productivity ◽  
Size Spectra ◽  
Fish Size ◽  
Density Dependent ◽  
Size Diversity

We studied fish size structure by using mean size, size diversity, and the slope of linear size spectra of six common European fish species along large-scale environmental gradients. We further analyzed the response of these three size metrics to environmental variables and to density-dependent effects, i.e., relative estimates of abundance (catch per unit effort, CPUE). We found differences in the strength of main predictors of size structure between the six species, but the direction of the response was relatively similar and consistent for most of the size metrics. Mean body size was negatively related to temperature for perch (Perca fluviatilis), roach (Rutilus rutilus), and ruffe (Gymnocephalus cernuus). Lake productivity (expressed as total phosphorus concentration) and lake depth were also predictors of size structure for four of six species. Moreover, we found a strong density dependence of size structure for all species, resulting in lower mean body size and size diversity and steeper size spectra slopes when density dependence increases. This suggests that density dependence is a key driver of fish size structure.

scholarly journals Fish Diversity as a Function of Depth and Body Size

2017 ◽  
Author(s):  
Klaus M. Stiefel ◽  
Timothy Joseph R. Quimpo
Keyword(s):  
Body Size ◽  
Fish Species ◽  
Scaling Laws ◽  
Large Body ◽  
Neutral Theory ◽  
Fish Diversity ◽  
Large Species ◽  
Species Numbers ◽  
Body Sizes ◽  
Reduced Rate

AbstractWe analyze the number of marine fish species as a function of fish body size and occurrence depth. For this purpose, we analyze the FishBase database. We compare these data to predictions of fish species numbers derived from the neutral theory of biodiversity combined with well-established ecological scaling laws, and measured oceanic biomass data. We consider several variants of these scaling laws, and we find that more large fish species exist compared to the prediction, which is especially true for elasmobranchs, possibly due to their overwhelmingly predatory niches. We find species numbers decreasing with occurrence depth somewhat quicker than our predictions based on the decrease of the number of individuals with depth indicates. This is especially true for the elasmobranchs. This is unsurprising, since the individuals versus depth data did not specifically determine elasmobranch biomass, and since sharks are known to be limited to depths < 3,000 m.Finally, we discuss how a reduced rate of speciation in larger animals could explain why large species are rare, in spite of the advantages of large body sizes outlined in Cope’s rule.

scholarly journals POTENTIAL PRODUCTION OF THE FIVE PREDOMINANT SMALL PELAGIC FISH SPECIES GROUPS IN THE JAVA SEA

2014 ◽  
Vol 20 (2) ◽  
pp. 59 ◽  
Author(s):  
Purwanto Purwanto ◽  
Duto Nugroho ◽  
Suwarso Suwarso
Keyword(s):  
Fish Species ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Pelagic Fish ◽  
Fish Stock ◽  
Potential Production ◽  
Small Pelagic Fish ◽  
Java Sea ◽  
Species Groups ◽  
Pelagic Fishery

The Java Sea is one of the important fishing areas for small pelagic fishery in Indonesia. The production of the fishery was dominated by five fish species groups. To support the management of  that  fishery,  an  assessment  of  the  stock  of  the  five  predominant  small  pelagic  fish  species groups was conducted. Based on the result of analysis, the maximum sustainable yield (MSY) of the stock of five predominant small pelagic fish species was about 244.6 thousand tons. Meanwhile, the MSY of the stock of the whole exploitable small pelagic fish species was about 315.5 thousand tons. The optimum fishing effort (EMSY) was 1032 units. The total fishing effort was higher than EMSY and the fish stock was likely over-exploited since 2000. To ensure the optimal fish production of the small pelagic fish stock in the Java Sea, it is necessary to recover fish stock by controlling fishing effort to EMSY. The time which it takes for the fish stock to recover was about two years when fishing effort was reduced from its level in 2009 to EMSY.

SHALLOW WATER HABITAT MAPPING AND REEF FISH STOCK ESTIMATION USING HIGH RESOLUTION SATELLITE DATA

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Vincentius P. Siregar ◽  
Sam Wouthuyzen ◽  
Andriani Sunuddin ◽  
Ari Anggoro ◽  
Ade Ayu Mustika
Keyword(s):  
High Resolution ◽  
Reef Fish ◽  
Satellite Imagery ◽  
Field Survey ◽  
Coral Cover ◽  
Fish Density ◽  
Fish Stock ◽  
Benthic Habitat ◽  
Live Coral ◽  
Stock Estimation

Shallow marine waters comprise diverse benthic types forming habitats for reef fish community, which important for the livelihood of coastal and small island inhabitants. Satellite imagery provide synoptic map of benthic habitat and further utilized to estimate reef fish stock. The objective of this research was to estimate reef fish stock in complex coral reef of Pulau Pari, by utilizing high resolution satellite imagery of the WorldView-2 in combination with field data such as visual census of reef fish. Field survey was conducted between May-August 2013 with 160 sampling points representing four sites (north, south, west, and east). The image was analy-zed and grouped into five classes of benthic habitats i.e., live coral (LC), dead coral (DC), sand (Sa), seagrass (Sg), and mix (Mx) (combination seagrass+coral and seagrass+sand). The overall accuracy of benthic habitat map was 78%. Field survey revealed that the highest live coral cover (58%) was found at the north site with fish density 3.69 and 1.50 ind/m2at 3 and 10 m depth, respectively. Meanwhile, the lowest live coral cover (18%) was found at the south site with fish density 2.79 and 2.18  ind/m2 at 3 and 10 m depth, respectively. Interpolation on fish density data in each habitat class resulted in standing stock reef fish estimation:  LC (5,340,698 ind), DC (56,254,356 ind), Sa (13,370,154 ind), Sg (1,776,195 ind) and Mx (14,557,680 ind). Keywords: mapping, satellite imagery, benthic habitat, reef fish, stock estimation

A new look on the morphometric characteristics of Congridae leptocephali from the southern Adriatic Sea

2021 ◽  
pp. 1-5
Author(s):  
M. Mandić ◽  
I. Leonori ◽  
A. De Felice ◽  
S. Gvozdenović ◽  
A. Pešić
Keyword(s):  
Fish Species ◽  
Adriatic Sea ◽  
Pelagic Fish ◽  
Morphometric Parameters ◽  
Morphological Features ◽  
Morphometric Characteristics ◽  
Small Pelagic Fish ◽  
Acoustic Surveys ◽  
Western Side ◽  
Conger Conger

Abstract Anguillid leptocephali of three Congridae species (Conger conger, Ariosoma balearicum and Gnathophis mistax) were caught as bycatch of pelagic trawls during acoustic surveys targeting small pelagic fish species in the southern Adriatic Sea, carried out under the framework of the Italian MEDIAS project (western side) and its extension in the ambit of the FAO AdriaMed project (eastern side). Results refer to the findings of Congridae leptocephali during surveys conducted in 2011, 2014, 2015 and 2016. A total of 25 specimens were caught and analysed (morphological features and pigmentation patterns). Leptocephali of Conger conger were found in the range of 8.4–13.1 cm total length (TL) (between 50 and 132 m depth), Ariosoma balearicum from 9.7–12.2 cm TL (between 50 and 128 m depth) and for Gnathophis mystax in the range from 6.4–11.7 cm TL (between 40 and 79 m depth). The results indicate that the southern Adriatic Pit could be the spawning area of these species in the Adriatic Sea. Present data represent a contribution to existing knowledge about the ecology of leptocephali from the Congridae family in the southern Adriatic Sea, and also indicate the existence of differences in morphometric parameters between different areas, that is, the possibility of the existence of new geographic lines within the genus Ariosoma in the Adriatic Sea.

Morphometrics and molecular analysis ofOzolaimus linstowin. sp. (Oxyuroidea: Pharyngodonidae) from the green lizardIguana iguana

2015 ◽  
Vol 90 (2) ◽  
pp. 186-198 ◽  
Author(s):  
S.V. Malysheva
Keyword(s):  
Body Size ◽  
Large Subunit ◽  
Buccal Capsule ◽  
Small Subunit ◽  
Present Species ◽  
Lsu Rdna ◽  
Adult Males ◽  
Spicule Length ◽  
Males And Females ◽  
Characteristic Features

AbstractOzolaimus linstowin. sp. is described from the large intestine ofIguana iguanaLinnaeus, 1758 from Mexico. The present species can be easily distinguished fromO. megatyphlonandO. cirratusby the presence of a long and slender pharynx not divided into sections, more similar to the remaining two species,O. monhysteraandO. ctenosauri. Ozolaimus linstowin. sp. can be differentiated fromO. monhysteraby the shorter spicule length and smaller body size of both males and females. Males ofO. linstowin. sp. are morphologically close to those ofO. ctenosauri, but females possess a markedly smaller body size and differ in the organization of the oral cuticular armature. Adult males ofO. linstowin. sp. bear some characteristic features of the J3 juvenile morphology in terms of the cuticular organization of the oral and buccal capsule. Phylogenetic analysis ofO.linstowin. sp. using partial small subunit (SSU) and D2–D3 large subunit (LSU) rDNA shows relationships with several Oxyuridae genera.

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