Expected Outcomes Mud Crabs

4. PROPOSED FUTURE ACTIVITIES FOR THE YEAR 2008

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PROGRAM DOCUMENT

Program Category: Departmental Program Program Title: Marine Fish Program

Responsible Department: Aquaculture Program Duration of Program: 2006-2009

1. INTRODUCTION

The Marine Fish Program was established to continually improve the technologies for broodstock management, seed production, nursery, and grow-out culture of commercially important marine fishes such as groupers (Epinephelus coioides and E. fuscoguttatus), the Asian sea bass (Lates calcarifer), mangrove red snapper (Lutjanus argentimaculatus), rabbitfish (Siganus guttatus) and milkfish (Chanos chanos). The development of breeding and seed production technologies for pompano (Trachinotus blochii) has been added to the program for this year.

2. PROGRAM 2.1. Objectives

The objectives are to: (a) improve the technologies for broodstock management, seed production, nursery, and grow-out culture of marine fishes such as groupers (Epinephelus coioides and E. fuscoguttatus), the Asian sea bass (Lates calcarifer), mangrove red snapper (Lutjanus argentimaculatus), rabbitfish (Siganus guttatus) and milkfish (Chanos chanos); and (b) develop breeding and seed production technologies for pompano (Trachinotus blochii).

2.2. Program Description

The program in 2007 comprises 20 studies that fall under Research and Development and Technology Verification and Dissemination. They span the various stages in culture involving, broodstock, seed production, nursery, and grow-out culture of marine fishes. Some projects involve the production of marine fishes in brackish water ponds and in floating net cages. The studies are done in laboratory, broodstock, and hatchery/nursery facilities at the Tigbauan Main Station, brackish water ponds in Dumangas Brackishwater Station, and in floating net cages at the Igang Marine Station.

3. PROGRESS OF ACTIVITIES IN THE YEAR 2007

Development of strategies to extend the spawning season of Asian sea bass (L. calcarifer) in captivity.

The study is ongoing with 5females/11males. The program needs more female broodstock.

Studies on the seed production techniques of milkfish and rabbit fish.

Heavy use of milkfish larval feed at the Integrated Broodstock and Hatchery facility. Use of larval feed starting on day 8 is now a standard protocol during larval rearing of milkfish and rabbit fish. Newly installed recirculating system has improved water quality and increased spawning frequency in milkfish.

Identification of molecular markers for egg quality in cultured marine species.

Primers for IGF-II and GH are being tested to be able to quantify the expression of IGF-II and GH mRNA by real time PCR.

Reproductive biology of pompano, Trachinotus blochii

Maturing gametes have been detected in adult fish but no spontaneous spawning has been observed. Induced spawning will be tried next.

Use of PUFA-rich thraustochytrids as enrichment diets for live foods (rotifers and Artemia ) in the larviculture of the sea bass, L. calcarifer.

Fatty acid analysis of Schyzochytrium strain of thraustochytrids from Leyte showed high levels of PUFA of which 34% was DHA, 7% was EPA, and 1% was ARA.

Assessment of the potential of mysid shrimps (Crustacea: Mysidacea) as live food in marine fish culture 2: Nutritional evaluation of mysid shrimps.

Proximate analysis showed high crude protein levels in wild mysids. Fatty acid analysis also showed high levels of EPA and DHA in wild mysids.

Improvement of the nutritional value of locally available feed resources for

practical aquatic feeds by submerged fermentation and solid substrate fermentation using milkfish gut bacteria and/or selected fungi.

Bacillus sp and Lactobacillus sp are among the non-pathogenic microorganisms present in milkfish anterior and mid intestine that could be used in fermentation of feed ingredients.

Positive identification is ongoing.

Evaluation of nutritional factors and microbial derivatives as immunostimulants in grouper, E. fuscoguttatus. Influence of environmental stress on innate immunity and resistance to bacteria in grouper fed various immunostimulants.

In trials involving unstressed or stressed (with hypoxic stress, i. e., aeration removed for 3-4 h for 3 consecutive days) fish and challenged with an intraperitoneal injection of a Vibrio isolate (10⁸ cfu/ml), mortality was nil in non-hypoxic fish while, in hypoxic fish, survival was greater in fish fed diets supplemented with immunostimulant (onion, ginger,  -glucan, or vitamin C) compared with fish fed unsupplemented diet (control). Data suggest that immunostimulants seem to protect stressed fish from Vibrio infection. Analysis of in vitro immune parameters is ongoing.

Verification studies on the seed production techniques of high value marine fish species such as grouper, red snapper, and sea bass.

New larval feed formulation for marine fish was easily accepted by larvae starting at day 15.

Grouper can be weaned to artificial diet at day 45 and sea bass at day 21.

Improvement of cage nursery rearing techniques for sea bass (L. calcarifer), grouper (Epinephelus spp) and mangrove red snapper (L. argentimaculatus) in earthen ponds.

Zooplankton was cultured in ponds for food of fry (grouper/ sea bass); dominant genera observed were Acartia, Calanus, Oithona, and Pseudodiaptomus. Studies of the population

70 Milkfish fingerling production in ponds.

Two trials were already done. In trial 1, low survival and high incidence of abnormalities in fry were observed probably due to fry coming from off-season spawning of milkfish. In trial 2, higher than 90% survival with low incidence of abnormalities of fry was observed from fry coming from early season spawning.

Effect of molluscicide and pesticide on snail population in milkfish grow-out production pond.

The molluscicide metaldehyde (75% META) was effective in treating moderate and heavy snail infestation in milkfish ponds. Initial trials showed that this formulation was better than other treatments including tobacco dust, ammonium sulfate/lime combination, and Terminator (containing saponin as active component), nicotinamiline sulfate, or handpicking (control) at recommended rates and application modes. However, if costs are considered Terminator, nicotinamiline sulfate, or ammonium sulfate/lime appears to be economically viable alternatives.

Verification of grouper and snapper diets in grow-out cages in pond.

Initial results showed growth and survival of fish fed SEAFDEC diet compared well or even better than those of fish fed commercial grouper/snapper diet. Lower survival of grouper compared with snapper was due to cannibalism.

Verification of sea bass grow-out diet in ponds.

Growth and survival of sea bass on SEAFDEC diet compared well with those fed commercial diet. Low survival (70%) of sea bass was due to cannibalism. In 2008, phased diets (starter/

grower/ finisher) will be tested.

Production of marine fishes in brackish water ponds. 1. Nursery cage fingerling production of sea bass, grouper, and mangrove red snapper in brackish water ponds.

Sea bass fry grew better when fed zooplankton than when fed trash fish. Grouper survival was low (3-8%) due to cannibalism.

Production of marine fishes in brackish water ponds. 2. Grow-out cage culture of sea bass, snapper, and siganid in pond.

Sea bass are now being cultured using SEAFDEC diet in the production ponds. Bigger fish (larger than 300 g) are being reserved for ABOT Negosyo’s sea bass festival. Smaller fish (less than 70 g) will be moved to floating net cages at IMS.

Production of marine fishes in brackish water ponds. 3. Grow-out culture of grouper, Epinephelus spp.

Groupers fed SEAFDEC diet are also being cultured in production ponds. Using bigger fish at initial stocking (20 g) market size fish can be obtained at DOC 260 with good survival rates.

About 1000 pc market size fish (>400 g) have already been sold.

Use of SEAFDEC formulated diet for milkfish cultured in marine cages (Verification study).

Trials for milkfish grow-out feed designed for milkfish culture in sea cages are ongoing. The diet is being compared with commercial milkfish feed.