Length-Weight Relationship and Relative Condition Factor of Arapaima gigas Schinz, 1822 from Extractive Reserve of Juruá River, Amazonas, Brazil

Abstract

Arapaima gigas (pirarucu) is a large fish greatly appreciated in Amazon region. The present work determined the weight-length relationship and the relative condition factor (Kn) of eviscerated pirarucu specimens from the extractive reserve (RESEX) of Juruá river, Amazonas, Brazil. The relative frequency distributions by weight class indicated amplitude between 20,000 and 115,000g and the classes of greatest frequency were between 30,000 and 80,000g. The equation 3.0157 that describes this relationship is W = 0.0092L , showing an isometric growth. Kn presented values of 0.98 ± 0.01, ranging between 0.94-1.01. The results indicate that fish stock of A. gigas in the RESEX of Juruá river presents good management conditions since most of the fish caught presented commercial weight and high utilization of meat, and also the equations of weight-length relationship and Kn values can be considered as reference for A. gigas eviscerated of the studied region.

Length-weight relationship and condition factor of eight fish species from the upper Araguari River, State of Amapá, Brazil

“…The R2 values of the LWR relationship of all fish species were higher than 0.737, and b values are within expected range for fish (Froese, 2006). Acestrorhynchus falcirostris, A. inermis, M. asterias, M. ternetzi and T. trilobatus presented negative allometric growth, which is expected for fish species with an elongated and/or rounded body shape, which is the case of species of the present study (Araújo & Vicentini, 2001); However, this pattern indicates that the fish is growing in length as expected, but its biomass gain is not corresponding to its length, different from what happens when the growth is isometric that is ideal for fish (Tavares-Dias, Araújo, Gomes, & Andrade, 2010), as occurred for A. falcatus, H. unimaculatus and H. aimara of the present study. However, b values of LWR are strongly influenced by gonadal maturity, feeding, seasonality, habitat and fish life stage (Froese, 2006;Prestes, Soares, Silva, & Bittencourt, 2010;Oliveira et al, 2018).…”

Morphometric evaluations and yields of commecial cuts of pirarucu (Arapaima gigas) in different weight classes

“…The terms "pirarucu deboned" and "pirarucu fillet" refer to the same product and may also be with or without skin. Factors such as sex, size and age of the fish can influence the yields obtained from processing after slaughter (Fogaça et al, 2011), in addition to variables intrinsic to the raw material, such as the feed condition of the animals, the stage of development of the gonads and environmental variables in force in the growth phase (Cunha et al, 2014). On the other hand, the processing yield can also vary due to factors extrinsic to the fish, such as the efficiency of filleting machines or the manual skill of the operator of these machines (Batalha et al, 2017).…”

“…The knowledge of the proportion of the raw material that will be transformed into final products for sale, as well as the quantity that will be part of the processing residue, allows the logistical planning of the production and the necessary calculations for the assessment of the company's productive efficiency (Ferreira et al, 2020). Thus, the establishment of ideal categories of weight at slaughter and the yields of fish meat, under their different forms of presentation, are of great importance for fish processing units and fish farmers (Cunha et al, 2014;Rodrigues et al, 2019).…”

“…In this way, pirarucu is marketed by the weight of the whole fish with an average regional sales value of US$ 1.53 kg -1 , and the processing industries prioritize animals weighing at least 8 kg. According to Cunha et al (2014), depending on the size, peculiarities of the fish, as well as characteristics that the final product must exhibit, different cleaning and cutting techniques are practiced.…”

Bioprospection of biocompounds and dietary supplements of microalgae with immunostimulating activity: a comprehensive review

“…This new research may represent an increase, albeit generic, in the potential for biotechnological applications to tropical ecosystems. The use of native microalgae is at least a sustainable alternative for the maintenance of fish stocks, given the emerging and intensive crops that will be present in the future due to demands for food and other human needs (Cunha et al, 2014; Pinaya et al, 2016; Campos-Silva & Peres, 2016; Silva Júnior et al, 2017).…”