Relationship between somatic growth and otolith growth: a case study of the ornate jobfishPristipomoides argyrogrammicusfrom the coast of Réunion (SW Indian Ocean)

Abstract

The ornate jobfish Pristipomoides argyrogrammicus Valenciennes 1832 occurs in the Indo-West Pacific Ocean, where it is harvested by small-scale coastal fisheries. Management of this species is hindered by lack of adequate biological data. We sampled a total of 113 individuals from the landings of local artisanal fishers on the island of Réunion (southwestern Indian Ocean), from March 2014 to March 2015. The relationships between two types of body length (total and standard length, cm) and total weight (g) were shown to be significant (p < 0.05). The length-weight relationship was described by a power function, with the scaling factor estimated to be 0.008 and the exponent 3.146. Age was determined using whole otoliths. The von Bertalanffy growth equation was estimated to be TLt = 30.68(1 e-0.52(t)). Otolith morphometry variables (length, width and area) were significantly correlated with age estimates (p < 0.05). No significant difference in age estimates was observed between left and right otoliths used as predictors. Readings from observed age and the estimates from modelled age indicated relatively good agreement, suggesting the potential to use whole otoliths for age estimation.

Relationships between fish and otolith dimensions of Epinephelus summana (Forsskål, 1775) and Cephalopholis argus (Schneider, 1801) from the Egyptian Red Sea coast

“…There are no significant between the TL and some of otolith measurements while there is a significant difference for other otolith measurements such as otlith length, weight, perimeter and aspect ratio for both grouper species. The present study agreed with other studies, which reported the significant for the side effect on the select of the left and right otolith (Mahé et al, 2017;Osman et al, 2018). Considering the findings in this study, the fish length and otolith measurements parameters are useful for most verifying the role of otoliths in the identification, discrimination and taxonomic classification of fish.…”

Age precision and growth rate of Rhabdosargus haffara (Forsskål, 1775) from Hurghada fishing area, Red Sea, Egypt

“…The variation in the type of growth may be due to environmental changes, food availability, feeding rate, different localities and other ecological factors (Bagenal and Tesch, 1978). The temporal effect is related to the spawning season (Mahé et al, 2017), length composition of the sampled species and the period of sampling (Moutopoulos and Stergiou, 2002;Mehanna and AlMamry, 2012).…”

Age and growth, mortality and exploitation ratio of Epinephelus summana (Forsskål, 1775) and Cephalopholis argus (Schneider, 1801) from the Egyptian Red Sea coast, Hurghada fishing area

“…This relationship is also used to measure the variation from the expected weight for a length of individual fish as an indication of fatness or gonad development and estimate the total yield of fish caught when length and number of fish are known. The relationship between length and weight may be assigned to factors like food accessibility and feeding rates (Bagenal and Tesch, 1978), the spawning season (Mahé et al, 2017), the size composition of the individuals sampled and the time of collecting specimens (Petrakis & Stergiou, 1995;Moutopoulos & Stergiou 2002;Mehanna & Al-Mamry, 2012).…”