Is resource partitioning the key? The role of intra‐interspecific variation in coexistence among five small endemic fish species (Characidae) in subtropical rivers

2018 ◽  
Vol 93 (2) ◽  
pp. 238-249 ◽  
Author(s):  
Mayara P. Neves ◽  
Jislaine C. Da Silva ◽  
Dirceu Baumgartner ◽  
Gilmar Baumgartner ◽  
Rosilene L. Delariva
Keyword(s):  
Fish Species ◽  
Resource Partitioning ◽  
Interspecific Variation ◽  
Endemic Fish

scholarly journals Iridescent structural colour production in male blue-black grassquit feather barbules: the role of keratin and melanin

2009 ◽  
Vol 6 (suppl_2) ◽  
Author(s):  
Rafael Maia ◽  
João Victor O Caetano ◽  
Sônia N Báo ◽  
Regina H Macedo
Keyword(s):  
Thin Film ◽  
Natural Variation ◽  
Single Layer ◽  
Coherent Scattering ◽  
Interspecific Variation ◽  
Stray Light ◽  
Main Role ◽  
Minimum Number ◽  
Keratin Layer

Iridescent coloration plays an important role in the visual communication system of many animal taxa. It is known that iridescent structural colours result from layers of materials with different refractive indexes, which in feathers usually are keratin, melanin and air. However, the role of these materials in the production of structural iridescent coloration is still poorly documented. Despite the great interspecific variation in the organization of such structures in bird plumage, melanin layers are usually considered too opaque, suggesting its main role is to delineate the outermost keratin layer and absorb incoherently scattered stray light. We combined spectrometry, electron microscopy and thin-film optical modelling to describe the UV-reflecting iridescent colour of feather barbules of male blue-black grassquits ( Volatinia jacarina ), characterized by a keratin layer overlying a single melanin layer. Our models indicate that both the keratin and the melanin layers are essential for production of the observed colour, influencing the coherent scattering of light. The melanin layer in some barbules may be thin enough to allow interaction with the underlying keratin; however, individuals usually have, on an average, the minimum number of granules that optimizes absorbance by this layer. Also, we show that altering optical properties of the materials resulted in better-fitting models relative to the empirically measured spectra. These results add to previous findings concerning the influence of melanin in single-layer iridescence, and stress the importance of considering natural variation when characterizing such photonic structures.

scholarly journals Length-weight Relations of 14 Endemic Fish Species from the Upper Yangtze River Basin, China

2013 ◽  
Vol 43 (2) ◽  
pp. 163-165 ◽  
Author(s):  
Jinming Wu ◽  
Lei Li ◽  
Hao Du ◽  
Hui Zhang ◽  
Chengyou Wang ◽  
...  
Keyword(s):  
River Basin ◽  
Fish Species ◽  
Yangtze River ◽  
Yangtze River Basin ◽  
Upper Yangtze River ◽  
Endemic Fish ◽  
The Upper Yangtze River

scholarly journals DINAMIKA POPULASI IKAN NILA (Oreochromis niloticus Linnaeus, 1758) DI DANAU PANIAI, PAPUA

2018 ◽  
Vol 23 (3) ◽  
pp. 193
Author(s):  
Samuel Samuel ◽  
Yoga Candra Ditya ◽  
Vipen Adiansyah
Keyword(s):  
Fish Species ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Lake Management ◽  
Nile Tilapia Oreochromis Niloticus ◽  
Average Maximum ◽  
Fish Samples ◽  
Information Research ◽  
Endemic Fish ◽  
Average Size

Introduksi ikan nila atau “serapia” (Oreochromis niloticus) di Danau Paniai bertujuan untuk meningkatkan diversitas hasil tangkapan dan mengurangi tekanan eksploitasi terhadap jenis ikan endemik. Pertumbuhan dan produksi ikan nila yang cepat tanpa diiringi upaya pengelolaan akan mengancam keberlanjutan ikan endemik di danau. Upaya pengelolaan sumberdaya ikan di suatu perairan membutuhkan informasi dinamika populasi. Penelitian dinamika dan pengelolaan populasi ikan nila dilakukan pada bulan Februari sampai Oktober 2016. Contoh ikan dikumpulkan dari hasil tangkapan nelayan dengan menggunakan jaring insang dengan berbagai ukuran mata jaring dan dari 4 (empat) enumerator pada tujuh stasiun pengamatan. Hasil penelitian menunjukkan populasi ikan nila di Danau Paniai didominasi ukuran panjang individu antara 15-25 cm sebanyak 67,24%. Pola pertumbuhan ikan jantan dan betina adalah isometrik, panjang maksimum rata-rata (L) adalah 37,28 cm dan koefisien pertumbuhan (K) adalah 0,50 per tahun. Mortalitas alami (M) dan mortalitas penangkapan (F) masing-masing sebesar 0,99 dan 0,54 per tahun. Tingkat eksploitasi (E) diperoleh nilai 0,35 lebih kecil dari nilai optimum (E=0,5). Ukuran rata-rata ikan nila tertangkap (Lc) adalah 20,55 cm lebih besar dari ukuran pertama matang gonad (Lm) sebesar 14,73 cm. Nilai Lc>Lm mengindikasikan sebagian besar populasi ikan nila di Danau Paniai sempat melakukan pemijahan sehingga pemanfaatan lebih atau sama dengan nilai optimum diharapkan dapat meningkatkan pemanfataan ikan nila di Danau Paniai. Introduction of nile tilapia (Oreochromis niloticus) in Lake Paniai known as “serapia” is aimed for improving the diversity of catches and reducing the exploitation pressure on the endemic fish species. The rapid growth, reproduction and production of nile tilapia without its management efforts is a new threat to the sustainability of the existence and utilization of endemic fish species in the lake. Management efforts of fish resources require population dynamics information. Research on the dynamics and management of nile tilapia populations was conducted from February to October 2016. Fish samples were collected from fishermen catches using nets with various mesh sizes and from four enumerators at seven observation stations. The results showed that the population of nile tilapia in Lake Paniai was dominated by individual length between 15-25 cm with frequency of 67,24%. The growth pattern of male and female fish were isometric, the average maximum length (L) was 37.28 cm and the growth coefficient (K) was 0.50 per year. Natural mortality (M) and fishing mortality (F) were 0.99 and 0.54 per year respectively. Exploitation rate (E) of 0.35 was smaller than the optimum value (E=0.5). The average size of nile tilapia captured (Lc) was 20.55 cm larger than the first size of gonad maturity (Lm) of 14.73 cm. The Lc value was higher than that the Lm value(Lc>Lm) indicating that most of nile tilapia population in Lake Paniai has spawned so that increasing the more or equal to the optimum value was expected to improve the of nile tilapia fish in Lake Paniai.

Niche Occupancy and the Relative Role of Micro-Habitat and Diet in Resource Partitioning Among Pond Dwelling Tadpoles

2009 ◽  
Vol 4 (3) ◽  
pp. 275-285 ◽  
Author(s):  
Vitor H. M. Do Prado ◽  
Mariluce G. Fonseca ◽  
Fernanda V. R. De Almeida ◽  
Orlando Necchi Junior ◽  
Denise De C. Rossa-Feres
Keyword(s):  
Resource Partitioning ◽  
Relative Role

scholarly journals Variability of functional traits and their syndromes in a freshwater fish species (Phoxinus phoxinus): The role of adaptive and nonadaptive processes

2019 ◽  
Vol 9 (5) ◽  
pp. 2833-2846 ◽  
Author(s):  
Allan Raffard ◽  
Julien Cucherousset ◽  
Jérôme G. Prunier ◽  
Géraldine Loot ◽  
Frédéric Santoul ◽  
...  
Keyword(s):  
Freshwater Fish ◽  
Functional Traits ◽  
Fish Species ◽  
Phoxinus Phoxinus ◽  
Freshwater Fish Species
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