Breeding and larval rearing of the milkfish Chanos chanos (Pisces: Chanidae)

Contribution No. 11 of the Aquaculture Department, Southeast Asian Fisheries Development Center, P.O. Box 256, Iloilo City 5901, Philippines.Two sexually maturing female milkfish were captured in April 1977 and induced to spawn by means of acetone-dried Pacific salmon pituitary powder. The eggs were fertilized and incubated and the resultant young reared to 74-day old, 11 cm long fingerlings. Newly fertilized eggs averaged 1.16 mm in diameter and each had a narrow perivitelline space containing several cortical granules which disappeared within a few minutes. The yolk was slightly yellowish, devoid of oil globules and very finely granulated. Embryonic development was very similar to that of other pelagic fish eggs and hatching occurred between 35 to 36 hr at a salinity of 32 ppt and a temperature range of 28.4-29.2°C.This study was partially supported through a grant to the SEAFDEC Aquaculture Department by the International Development Research Centre of Canada, under Project No. 3-P-74-0146

Capture, transport and domestication of adult milkfish, Chanos chanos

Methods used in the capture, transport and domestication of adult milkfish are described and illustrated

Spawning of milkfish, Chanos chanos, in captivity

Newly captured milkfish released 0.8 mm in diameter non-hydrated eggs spontaneously in captivity. After injection with partially purified salmon gonadotropin (SG-G100), 1.2 mm in diameter hydrated eggs were released. These eggs, however, were not fertilized

Morphological measurements, gonadal development and estimated age of adult milkfish, Chanos chanos captured in Pandan Bay from 10 May - 16 June, 1975

From 10 May to 16 June, 1975, 106 adult milkfish were captured in an otoshi-ami 500 meters offshore. Of the 106 specimens, 37 were females in various stages of gonadal development or spent and 69 were males of which 41 were sexually mature. The age of these fishes were estimated to be between 3 and 5 years

Qualitative analysis of the contents of the anterior portion of the oesophagus from adult milkfish, Chanos chanos, captured in Pandan Bay from 10 May-June 1975

Qualitative analysis of food items in the anterior spiral portion of the oesophagus suggests that adult milkfish feed on both benthic and planktonic materials

The occurrence of milkfish Chanos chanos fry in Pandan Bay, Antique, from 21 May to 25 June, 1975

Milkfish fry were collected at the Pandan shoreline and 500 meters offshore. While shore-caught fry were uniform in size those captured offshore varied in size and stage of development

Collection, storage, transport, and acclimation of milkfish fry and fingerlings

The present methods of collecting fry and fingerlings involve filtration by mobile or stationary devices. The bottom topography of the fry ground, wind direction, and tidal fluctuations are the most important considerations in the design and construction of fry and fingerling catching gear. The behavior of young milkfish (Chanos chanos ) in the different environments where they are exploited determines the catching methods to be employed. Collection, handling, storage, and transport activities expose the fish to undue stress, which contributes to poor survival. The simple method of lowering the salinity of the water medium considerably reduces mortality. Prior acclimation history has significant effects on subsequent survival and adaptation. Although it appears that milkfish fry are more hardy than the fingerlings, both have the same capability for resisting subsequent environmental stress provided sufficient time is given for the fish to recover from previous stress

Milkfish fry and fingerling industry of the Philippines: methods and practices

2nd Edition.Milkfish fry catch from Philippine waters can still be increased. Intensified collections in traditional fry grounds and exploitation of new areas may lead to a reduction of adult stock and the possible collapse of the milkfish fry fishery. The implementation of rational conservation and management measures are of immediate concern not only to increase the productivity and number of fry grounds but also to conserve this important aquatic resource. The present methods of catching milkfish fry involve fry filtration by mobile or stationary devices. The design, construction, area and time of operation of the gears are primarily dictated by the bottom topography of the fry grounds, wind direction, local current patterns and tidal fluctuations. Catching, handling, storage and transport activities expose the fish to undue stress which contribute to poor survival. The simple method of lowering the salinity of the water medium considerably reduces mortality. High mortality in nursery ponds has aggravated the seed shortage problem of the milkfish industry. The development of an efficient mass-production technology in rearing milkfish fry to fingerlings and in stunting fingerlings for longer periods could offer the solution not only in meeting the requirements for milkfish seed but also provide part of the fry requirements of other countries in the region.This study was partially supported by the Canadian International Development Research Centre

How to transport and acclimate prawn fry

The manual describes the procedures and techniques to follow for short and long duration transport of prawn fry. Regulations for acceptance and handling of wet shipment and the acclimation of the fry are also covered