Thicklip (Chelon labrosus) and flathead (Mugil cephalus) grey mullets fry production in Tunisian aquaculture

Recombinant Fsh and Lh therapy for spawning induction of previtellogenic and early spermatogenic arrested teleost, the flathead grey mullet (Mugil cephalus)

“…Not only larvae survived longer without the application of external feeding, but also larvae reared using mesocosm conditions demonstrated the potential to develop until juveniles, indicating that eggs and larvae obtained after the induction of gametogenesis with rFsh and rLh could supply a hatchery. Indeed, larval development and growth in our study, using mesocosm rearing conditions, was very similar to other published studies either using intensive or extensive conditions (Abraham et al, 1999;Besbes et al, 2020;El-Gharabawy and Assem, 2006;Loi et al, 2020). Most of these studies, emphasized the effects of algal addition to the rearing tanks (green water technique) as the best way to optimize larval feeding on rotifers due to its effect not only in facilitating the contrast but also improving the nutritional state and / or health of the rotifers (Tamaru et al, 1994).…”

“…Growth was accelerated from 13 dph to 35 dph when they reached 5 mm TL and then until day 39 when they reached almost 7 mm TL. The exponential growth recorded in the present study (Fig 14) was similar to that described by Besbes et al (2020). Therefore, it was promising that the larvae reared in the mesocosms demonstrated similar grow and development as other studies on flathead grey mullet larvae indicating the potential for hatchery production of larvae from adults that had gametogenesis-induced with rGths.…”

“…Many other studies worked with fully mature females and applied different treatments to induce oocyte maturation and spawning. For example, Aizen et al (2005) applied GnRHa (10 µg kg -1 priming, 20 µg kg -1 resolving) combined with Metoclopramide (15 mg kg -1 priming and resolving), El-Gharabawy and Assem ( 2006) injected 20 to 70 mg kg -1 carp pituitary extract or 10,000 IU fish -1 hCG as priming and one or two resolving injections of 100 -200 µg kg -1 GnRHa, while Besbes et al (2020) treated with a priming dose of 10,000 IU kg -1 hCG and resolving of 10,000 IU kg -1 hCG and 200 µg kg -1 . Those treatments respectively resulted in: (i) 85% spawning success with low (< 40%) to high (< 90%) fertilization percentages and fecundities of 1,649,000 eggs kg -1 bw, (ii) 40 % spawning success with 75 to 80 % fertilization and fecundities of 1,395,000 eggs kg -1 bw, and (iii) 100 % success with 63 % fertilization but low fecundities of 418,945 eggs kg -1 bw.…”

“…Most of these studies, emphasized the effects of algal addition to the rearing tanks (green water technique) as the best way to optimize larval feeding on rotifers due to its effect not only in facilitating the contrast but also improving the nutritional state and / or health of the rotifers (Tamaru et al, 1994). Larval growth in size was similar to what Besbes et al (2020) described, with larvae measuring 2.1 mm TL at hatching, and 2.96 mm TL at 4 dph, followed by a stagnated growth between 4 dph and 11 dph when the larvae reached 3.5 mm TL. Growth was accelerated from 13 dph to 35 dph when they reached 5 mm TL and then until day 39 when they reached almost 7 mm TL.…”

Characterization of the different behaviours exhibited by juvenile grey mullet (Mugil cephalus) under rearing conditions

“…The economic importance of Mugil is based on its consumption and its cost varies from one region to another, relying on several factors; for example, female’s grey mullet gonads, also known as caviar or bottarga, could reach 65 € per kg in the European markets (Aldana, 2015; Rodríguez, 2018). Therefore, significant advances have been made on nutrition, growth, larval culture and reproduction of individuals reared in captivity (Martínez et al ., 2019; Talukdar et al ., 2020; Besbes et al ., 2020; Ramos-Júdez et al ., 2021). Furthermore, several studies have demonstrated that grey mullet can also be an adequate candidate species for mariculture which can contribute to food production and the reduction of fishing impact (Saleh, 2008; Robles & Mylonas, 2017).…”