Improvement of seed production by SISP-B (Semi Intensive Seed Production with Balanidae)

Improvement of seed production by SISP-B (Semi Intensive Seed Production with Balanidae)

Abstract

Wild captured cabrilla común (Paralabrax humeralis) spawn 19 million eggs and 9 million larvae hatch-out from November 2018 to April 2019. The spawning occurred water temperature 18 to 20 °C mainly. Several SISP （Semi Intensive Seed Production）were operated and improved the method. SISP method is different from intensive method as SISP feed natural growing wild copepod instead of rotifer and Artemia that create intensively. Thus SISP not only require several tanks and equipment (pump, filter, UV etc.) but also high level technique and experience. SISP makes anybody produce premium juvenile easily without large investment. Remarkably we found that the larvae eat picoroco nauplius (Austromegabalanus psittacus) which nauplius grows bigger and longer than copepod and blue mussel. Also produce picoroco nauplius easier than copepod that collect in coast and just hang in the SISP tank. We modified SISP-C to SISP-B and producing some cabrilla juveniles.

Introduction

Wild captured cabrilla común (Paralabrax humeralis) spawn 19 million eggs and 9 million larvae hatch-out from November 2018 to April 2019. The spawning occurred water temperature 18 to 20 °C mainly. Several SISP （Semi Intensive Seed Production）were operated and improved the method. SISP method is different from intensive method as SISP feed natural growing wild copepod instead of rotifer and Artemia that create intensively. Thus SISP not only require several tanks and equipment (pump, filter, UV etc.) but also high level technique and experience. SISP makes anybody produce premium juvenile easily without large investment. Remarkably we found that the larvae eat picoroco nauplius (Austromegabalanus psittacus) which nauplius grows bigger and longer than copepod and blue mussel. Also produce picoroco nauplius easier than copepod that collect in coast and just hang in the SISP tank. We modified SISP-C to SISP-B and producing some cabrilla juveniles.

Material and Method

The SISP operated cuboid tank (3 x 3 x 2.4 m, 20 m³) and round tank (6.4Ø m x 1.2 m, 35 m³), large volume tank minimizes fluctuation of water temperature and improves phytoplankton propagation. At beginning, supplied sea water through 1 m/m bag-net, gave aeration and fertilizer, potassium nitrate 3 g/m³ and triple superphosphate 0.5 g/m³. Supplied water 10 % a day continually and control propagation of phytoplankton. We maintained pH 8.2 to 8.6 with water supply, fertilizer application and sheading surface. After a week phytoplankton (Chaetoceros spp.) grew and water color turned to brown (Figure).  Selected premium larvae, floating egg rate and hatch-out rate show over 90 %, high survival rate until DPH2 (Days Post Hatch-out), and stocked in the tank at density of 2 and 3 larvae/L.

We took one litter of water and filtered by 63 µm mesh (Figure).  Nauplius of copepod and picoroco, copepod adult and Polychaeta larva were counted daily. Fed grinded Choro gonad (Mytilus chilensis, 1 million eggs/g, Figure) during DPH3 to 13. Also we fed Balanidae nauplius that installed inside Nauplius Supplier (NAS) or keep in pail, 1 Kg/10 m³, and supply water continually (Figure).

Result

The culture SISP190310 started with round tank (SISP3, 35 m³, plastic swimming pool) on March 10 and stocked 70,000 of hatch-out larva on March 31. We fed choro eggs and installed NAS, and live feeds propagated over 200 per liter. We harvested 45 larvae, LT 22mm and BW 0.14g, on DPH 45, survival rate 0.06 %, on May 15. The reason of low survival is mas-mortality just after stocking possibly. Because this batch was not confirmed survival from DPH 0 to 2, sometime mortality occurs before start eating feeds due to larva handling and quality of eggs.

 

The culture SISP190402 operated with cuboid tank (SISP1, 20 m³, FRP) on April 2 and stocked 30,000 of hatch-out larva on April 14. However we couldn’t see the larvae after few days. Thus restock 60,000 hatch-out larvae additionally and hundreds of larvae are visible at DPH30. We fed choro eggs, installed 3 kg of picoroco and fed artificial feeds (Otohime C2). Live feeds grew over 100 per liter but microalgae not propagate well recently due to cloudy weather. Thus recommend prepare some microalgae pools additionally those feed to SISP tank when microalgae propagation is slow down.

 

Discussion

Based on several operations of SISP, we recommend following production model of SISP-B.

1.    Introduce initial water through 1 m/m mesh bag-net, covered by black Rachel (85 %), and apply fertilizer, potassium nitrate 3 g/m³ and triple superphosphate 0.5 g/m³, with gentle aeration. Water supply 5 % daily continually.

2.    Wait few days to propagate Chaetoceros spp. and water color turn to brown. Possibly some nauplius and adult of copepod are appear.

3.    Stocking hatch-out larva at density of 2 to 5 larvae/m³ of SISP tank volume to Monitoring tank (conical 500L) which floating inside SISP tank. Observe larva survival until DPH2 and release to SISP tank if survival rate show over 80 %.

4.    Feeding blue mussel gonad at quantity of 1 g/ m³ from DPH3 to 13 daily. Also install Nauplius Supplier (NAS) with barnacles 2 Kg/10 m³ from DPH5 to 60. If reduce microalgae in SISP tank, supply water from phytoplankton tank, swimming pool (6.5Øx1.2m), by diaphragm pump or gravity. Feed artificial feeds for larva to juvenile, e.g. Otohime C1 (650 µm) and C2 (1.1 mm) from DPH25 depend on size of juvenile and availability of live feeds.

5.    Harvest totally on DPH45 to 60 when juvenile reach to 3 cm and keep in nursery tank, 2 to 4 m³ round tank and rearing intensively, feed only artificial feeds and high water exchange with water current.