Food selection of early grouper, Epinephelus coioides, larvae reared by the semi-intensive method

Conference paper

Feeding habits of hatchery-reared grouper, Epinephelus suillus larvae

MN Duray - In CL Marte, GF Quinitio & AC Emata (Eds.), Proceedings of the Seminar-Workshop on Breeding and Seed Production of Cultured Finfishes in the Philippines, Tigbauan, Iloilo, Philippines, 4-5 May 1993, 1996 - Aquaculture Department, Southeast Asian Fisheries Development Center

The feeding habits of hatchery-reared Epinephelus suillus larvae were determined by examining their gut contents. The larvae (2.6 mm TL) were initially fed rotifers on day 2 and newly-hatched Artemia nauplii on day 21 (9.1 mm TL). The amount of rotifers initially ingested averaged 1.3 individuals/larva. The ingestion rate increased as larvae grew. Larvae immediately showed strong preference for Artemia to rotifers on the first day of introduction. E. suillus larvae showed diurnal feeding pattern at day 7 (3.6 mm TL), day 14 (4.9 mm TL), day 21 (9.1 mm TL) and day 28 (11.1 mm TL). Feeding incidence decreased in the evening and was nil at 2100-2200 h. Active feeding started earlier in older larvae and satiation was between 0900-1000 h. The results of this study will be used as a basis in developing a good feeding scheme for E. suillus larvae.

Article

Larval and early juvenile development of silver therapon, Leiopotherapon plumbeus (Actinopterygii: Perciformes: Terapontidae), reared in mesocosms

FA Aya, MNC Corpuz, MA Laron & LMB Garcia - Acta Ichthyologica et Piscatoria, 2017 - Szczecińskie Towarzystwo Naukowe

The silver therapon, Leiopotherapon plumbeus (Kner, 1864), is an endemic and economically important freshwater food fish in the Philippines. The natural populations of this species have been declining during the past years, mainly due to intense fishing pressure, habitat degradation, and introduction of invasive alien species. At present, it is considered a target species for domestication and conservation efforts. Despite several attempts of artificial reproduction and larval rearing, little is known on larval and early juvenile development of silver therapon. The presently reported study was therefore intended to fill this gap in the knowledge by determining the growth and describing body proportions, pigmentation, and fin formation of this fish. Newly hatched larvae were reared in mesocosm tanks at a mean temperature of 29.5°C. Larvae up to 30 days after hatching were sampled at irregular intervals and preserved in 5% buffered formalin. Early development stages for 245 preserved specimens were described in detail with reference to changes in morphology, growth and body proportions, pigmentation, and fin formation. Five developmental stages of silver therapon were identified: yolk sac larva (1.88 mm TL), preflexion (2.51 mm TL), notochord flexion (4.50-8.27 mm TL), postflexion larva (6.90-12.21 mm TL), and early juvenile (>13.40 mm TL). Growth was isometric for eye diameter and gape size whereas positive allometry was observed for body depth, head length, and preanal length. Some body proportions showed abrupt changes from preflexion to postflexion larvae before it stabilized during the early juvenile stage. Pigmentation in the form of stellate and punctate melanophores increased with developmental stage, with larvae becoming heavily pigmented from postflexion to early juvenile stage. These morphological changes, together with the full complement of fin rays and squamation observed in specimens larger than 13.4 mm TL, suggest the attainment of the juvenile stage of this species. These morphological changes may explain the food and feeding habits during the early life stages of silver therapon which is critical to their survival and recruitment in the wild and in a mesocosm hatchery environment.

Article

Preliminary investigation of feeding performance of larvae of early red-spotted grouper, Epinephelus coioides, reared with mixed zooplankton

M Doi, JD Toledo, MSN Golez, M de los Santos & A Ohno - Hydrobiologia, 1997 - Springer Verlag

Larvae of red-spotted grouper, Epinephelus coioides, were reared in outdoor tanks with nauplii of copepods (mainly Pseudodiaptomus annandalei and Acartia tsuensis) and/or rotifers, Brachionus rotundiformis. Grouper larvae successfully started feeding on early stage nauplii even though their abundance was as low as approximately 100 individuals l^-1 and showed better survival and growth thereafter compared to those fed with rotifers only. Incidence of feeding reached 100% on day 4 when nauplii were available and only on day 9 when rotifers were given alone. Larvae seemed to be poor feeders at the onset of feeding, attempting to capture any food organisms in the tank water. Selective feeding ability of larvae started from day 4 and the larvae then preferred to feed on medium- and large-size nauplii rather than on rotifers as they grew. Larvae appeared to have a better chance at surviving in the presence of early stage nauplii, which were probably caught more easily than rotifers.