scholarly journals Feeding selectivity of early-stage fish larvae on the nauplii and eggs of different copepod species

2017 ◽  
Vol 12 (2) ◽  
pp. 115-122 ◽  
Author(s):  
Aiko Mitsuzawa ◽  
Hiroyuki Miyamoto ◽  
Hiroshi Ueda
Keyword(s):  
Fish Larvae ◽  
Early Stage ◽  
Copepod Species ◽  
Feeding Selectivity

Temporal patterns in distributions of tropical fish larvae on the North West Shelf of Australia

2004 ◽  
Vol 55 (5) ◽  
pp. 473 ◽  
Author(s):  
A. Sampey ◽  
M. G. Meekan ◽  
J. H. Carleton ◽  
A. D. McKinnon ◽  
M. I. McCormick
Keyword(s):  
Southern Oscillation ◽  
Fish Larvae ◽  
Early Stage ◽  
Larval Survival ◽  
Zooplankton Biomass ◽  
Tropical Fish ◽  
North West ◽  
Larval Fishes ◽  
The North ◽  
Abundance And Diversity

Information on the temporal distributions of tropical fish larvae is scarce. Early stage larval fishes were sampled using towed bongo plankton nets at sites on the southern North West Shelf of Australia (21°49′S, 114°14′E), between October and February of 1997/98 and 1998/99. The first summer was characterised by El Niño–Southern Oscillation-driven upwelling and high primary productivity, whereas in the second summer water temperatures were warmer and primary production was lower. Benthic percoid shorefishes dominated surface assemblages in both summers and this pattern may be typical of tropical shelf environments.The abundance and diversity of larval fishes were lowest in October and increased from November through to February. Assemblages displayed weak cross-shelf patterns, with a few taxa being more abundant at inshore sites (e.g. monacanthids), whereas others were more abundant offshore (e.g. scombrids). Although the composition of assemblages remained relatively consistent, many taxa (e.g. pomacentrids and carangids) showed differences in abundance between summers. Multivariate analyses found no relationships between abundance patterns of larval fishes and biophysical variables, such as temperature, salinity, and zooplankton biomass. Thus, seasonal changes in abundance may reflect differences in the spawning activities of adult fishes and/or larval survival.

Distribution of fish larvae within a weakly tidal mangrove lagoon

2017 ◽  
Vol 68 (2) ◽  
pp. 396
Author(s):  
J. Jaxion-Harm ◽  
M. R. Speight
Keyword(s):  
Dna Analysis ◽  
Full Moon ◽  
Hydrodynamic Force ◽  
Fish Larvae ◽  
Early Stage ◽  
Shallow Waters ◽  
Light Traps ◽  
Larval Distribution ◽  
New Moon ◽  
Distribution Of Fish

Mangroves have been shown to provide valuable nursery grounds to juvenile fishes, yet little is known regarding larval distribution and settlement processes in this habitat. To investigate fish larvae in mangrove habitat in a semi-isolated lagoon (surface area 750m2), we employed multiple catch methods: plankton tows, minnow traps, and light traps during June–August 2008 and 2009. Overall, nine families of fish larvae were caught in the light traps. Light traps caught significantly more fish larvae during the new moon compared with the full moon. Plankton tow nets caught early-stage, unidentifiable (without DNA analysis) larvae. Minnow traps only caught a total of three fish larvae. Overall, scarids (parrotfish) and lutjanids (snappers) were the most common larvae from coral-reef fish families and were found at sites over 1km upstream of the mouth of the mangrove lagoon. Without the aid of tidal influence (and nets requiring hydrodynamic force), sampling is difficult in these turbid, shallow waters.

Relationship between gape size and feeding selectivity of fish larvae from a Neotropical reservoir

2008 ◽  
Vol 72 (7) ◽  
pp. 1690-1707 ◽  
Author(s):  
M. C. Makrakis ◽  
K. Nakatani ◽  
A. Bialetzki ◽  
L. C. Gomes ◽  
P. V. Sanches ◽  
...  
Keyword(s):  
Fish Larvae ◽  
Feeding Selectivity ◽  
Gape Size

Changes in Behaviour of Atlantic Halibut (Hippoglossus hippoglossus) and Turbot (Scophthalmus maximus) Yolk-Sac Larvae Induced by Bacterial Infections

1993 ◽  
Vol 50 (12) ◽  
pp. 2552-2557 ◽  
Author(s):  
Anne Berit Skiftesvik ◽  
Øivind Bergh
Keyword(s):  
Bacterial Infections ◽  
Fish Larvae ◽  
Early Stage ◽  
Scophthalmus Maximus ◽  
Yolk Sac ◽  
Atlantic Halibut ◽  
Hippoglossus Hippoglossus ◽  
Pathogenic Vibrio ◽  
Turbot Scophthalmus Maximus ◽  
Reduced Activity

Eggs of Atlantic halibut (Hippoglossus hippoglossus) and turbot (Scophthalmus maximus) were exposed to Flexibacter ovolyticus and pathogenic Vibrio sp. strains prior to, and during hatching. Activity, buoyancy and mortality of the yolk sac larvae were monitored from hatching until time of first feeding. The halibut larvae showed reduced activity and increased mortality in response to the challenge of bacteria, compared to uninfected control groups. In addition, the infected halibut larvae showed increased specific density compared to the uninfected larvae. These responses were not found for turbot. However, turbot larvae infected with Vibrio anguillarum had lower activity than larvae infected with F. ovolyticus. The reduced activity of halibut larvae occurred 1–2 weeks prior to the increased mortality, allowing infections to be detected at an early stage. The results suggest that the behaviour of fish larvae is influenced by bacterial infection.

scholarly journals eDNA metabarcoding of small plankton samples to detect fish larvae and their preys from Atlantic and Pacific waters

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Eva Garcia-Vazquez ◽  
Oriane Georges ◽  
Sara Fernandez ◽  
Alba Ardura
Keyword(s):  
High Throughput Sequencing ◽  
Fish Larvae ◽  
Early Stage ◽  
Zooplankton Community ◽  
Coi Gene ◽  
Fish Diet ◽  
Commercial Fish ◽  
Tropical Waters ◽  
Small Water ◽  
Sampling Protocols

AbstractZooplankton community inventories are the basis of fisheries management for containing fish larvae and their preys; however, the visual identification of early-stage larvae (the “missing biomass”) is difficult and laborious. Here, eDNA metabarcoding was employed to detect zooplankton species of interest for fisheries from open and coastal waters. High-Throughput sequencing (HTS) from environmental samples using small water volumes has been proposed to detect species of interest whose DNA is the most abundant. We analyzed 6-L water samples taken from subtropical and tropical waters using Cytochrome oxidase I (COI) gene as metabarcode. In the open ocean, several commercial fish larvae and invertebrate species important in fish diet were found from metabarcodes and confirmed from individual barcoding. Comparing Atlantic, Mediterranean, Red Sea, and Pacific samples we found a lower taxonomic depth of OTU assignments in samples from tropical waters than in those from temperate ones, suggesting large gaps in reference databases for those areas; thus a higher effort of zooplankton barcoding in tropical oceans is highly recommended. This and similar simplified sampling protocols could be applied in early detection of species important for fisheries.

scholarly journals Report on five species of harpacticoid copepods from vegetative area of Sungai Pulai, Johor

2018 ◽  
Vol 14 (2) ◽  
pp. 284-288
Author(s):  
Zaleha Kassim ◽  
Hazwani Hanim Hasnan ◽  
Syazleen Zainal ◽  
Nurul Huda Ahmad Ishak
Keyword(s):  
Fish Larvae ◽  
Marine Ecosystem ◽  
Harpacticoid Copepod ◽  
Copepod Species ◽  
Taxonomic Study ◽  
Body Parts ◽  
Seagrass Bed ◽  
Preferred Habitat ◽  
Sea Bottom ◽  
Harpacticoid Copepods

Bottom vegetation is known as preferred habitat for many types of meiofauna such as copepods. The conditions of sea bottom that include vegetation could contribute to the copepod’s assemblage. Being an important diet for fish larvae, information on copepod species promotes effort for conservation of both fish species and marine ecosystem. Nonetheless, identification and taxonomic report on copepods from such areas are still scanty. Samples of copepods were collected by scrapping the uppermost 10cm of sediment of bottom area at Sungai Pulai’s seagrass-bed during low tide. Sediment was decanted to extract the copepods which later be preserved in 5% buffered formalin.  Body parts were dissected under microscope and prepared for taxonomic study. All drawings made with the help of Lucida tube were used for comparison with established key of identification. Five families were noted in this study; Ameridae Monard, Lang, Parastenhelia Thompson & A. Scott, Dactylopusiidae Lang, Tisbidae Sars and Diosaccidae Sars. Harpacticoid copepod species described from this study were Ameira sp. (Ameridae Monard, Lang), Parastenhelia sp. (Parastenhelia Thompson & A. Scott), Paradactylopodia sp. (Dactylopusiidae, Lang), Idyanthepusilla (Tisbidae, Sars) and Stenhelia sp. (Diosaccidae Sars).  Further study on functional morphology would explain their adaptability to both conditions of sea bottom.

scholarly journals Development of Digestive Enzyme of Patin Pangasius hypohthalmus Larvae

2007 ◽  
Vol 5 (1) ◽  
pp. 41
Author(s):  
I. Effendi ◽  
D. Augustine ◽  
. Widanarni
Keyword(s):  
Survival Rate ◽  
Digestive Enzymes ◽  
Fish Larvae ◽  
Early Stage ◽  
Digestive Enzyme ◽  
Natural Food ◽  
Larval Rearing ◽  
Feeding Period ◽  
Feeding Regime ◽  
Enzymes Activity

<p>Culture of patin <em>Pangasius hypophthalmus </em>especially larval rearing  very depends on the supply of natural food as energy source.  <em>Artemia</em> is the main natural food for fish larvae as a starter food, but its price is high.  To reduce production cost, farmers tend to reduce the feeding frequency and shorten  the <em>Artemia </em>feeding period.  Altering feeding regime however may reduce fry quality. This relate to the availability of digestive enzymes.  The objective of this study was  to examine digestive enzymes activity in patin larvae fed with  different feeding regime.  By shorten feeding period with <em>Artemia</em> to 2-4 days and <em>Tubifex</em>,substitution, the enzymes activity of protease, lipase and amylase were revealed similar pattern   The enzymes activity tends to increase and reach the peak at day 7 , and decrease later on until day 15 after hatching.  Survival rate of fish were varied for each treatment, and the highest survival rate was obtained when larvae were fed by <em>Artemia </em>for 8 days.  Blood worm were not fully digested by patin larvae at early stage.</p> <p>Keywords: enzyme, digestion, patin, <em>Pangasius hypophthalmus</em></p> <p> </p> <p>ABSTRAK</p> <p>Proses budidaya ikan patin, <em>Pangasius hypophthalmus</em> terutama pembenihan sangat tergantung oleh ketersediaan pakan alami sebagai sumber energinya. <em>Artemia</em> merupakan pakan alami yang banyak diberikan pada saat larva ikan mulai makan, namun harganya relatif tinggi. Untuk menekan biaya produksi, petani ikan patin cenderung mengurangi frekuensi pemberian <em>Artemia </em>dan mempersingkat waktu pemberiannya. Penggeseran jadwal ini diduga mengakibatkan penurunan kualitas benih ikan patin yang dihasilkan yang berhubungan dengan kesiapan enzim pencernaannya. Penelitian ini dilakukan untuk mengetahui aktivitas enzim pada larva ikan patin dengan jadwal pemberian pakan yang berbeda. Dengan memotong waktu pemberian <em>Artemia</em> 2 - 4 hari dan disubstitusi dengan <em>Tubifex</em>, aktifitas enzim protease, lipase dan amilase pada larva ikan patin, memiliki pola yang sama. Aktifitas enzim cenderung meningkat dan mencapai puncak pada umur 7 hari, selanjutnya terus menurun sampai larva berumur 15 hari. Kelangsungan hidup ikan selama penelitian berbeda-beda untuk setiap perlakuan dengan nilai tertinggi dicapai oleh larva yang diberi pakan <em>Artemia</em> sampai berumur 8 hari. Larva ikan patin belum siap sepenuhnya untuk menerima pakan berupa cacing sutera sejak stadia awalnya.</p> <p>Kata kunci: Enzim, Pencernaan, Patin, <em>Pangasius hypophthalmus</em></p>

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