15 OCTOBER 1999
FISH FEEDING OF DOUBLE-ENDED PIPEFISH, SYGNATHOIDES BIACULEATUS, LARVAE
Adult male double-ended pipefish carrying eggs were collected from Ambon Bay in Indonesia and were placed in 25-liter glass aquarium where the eggs were allowed to hatch. To determine the time of first feeding, approximately 25 newly hatched larvae were placed in a separate aquarium equipped with continuous aeration. The remainder of the spawn were stocked in a 25-l glass aquarium and presented copepods from the day of hatching at approximately 0.5-1.0 individuals/ml. At 24-h intervals, samples from each group were weighed and the change in body weight was recorded during the first seven days posthatching. There was no growth exhibited by the larvae not given any food and this differed significantly from those that were fed copepods. Most important was that the difference in growth between fed and unfed larvae was already apparent by the second day posthatching which indicates that the pipefish larvae feed from the time they hatch.
One brood of 129 hatched larvae was stocked into a 25-l aquarium and a 30-day rearing trial was completed using wild copepods as the sole source of food. A statistical model (LnBW=(0.116*Days)-4.048, where BW is body weight in grams and Days equal the number of days posthatched, was found to provide the best fit of the data. Survival at 30 days posthatching was 80%.
The surprising results indicate that the larval-rearing activity for the artificial propagation of this species does not present as difficult an obstacle as expected. In contrast to most marine fish, pipefish larvae hatch at an advanced stage of development and their mouth size allows them to utilize wild zooplankton (>500 um) as an initial food. However, the one contstraint that may impede the mass culture of the double-ended pipefish appears now to be providing the enormous amount of copepods (zooplankton) necessary for growth. During the rearing trial, an average food density of 1 individual/ml/day (e.g., 25,000 copepods/day/tank) was provided for the 30-day trial and just to support a little over one hundred pipefish larvae. Additional research should be conducted on the use of commercial feeds for growout of double-ended pipefish.
(excerpts of article by C.S. Tamaru, University of Hawaii, Sea Grant Extension Service; C. Carlstrom-Trick, Hawaii C's Aquaculture Consultant Services; Bob Mosse and H. Lolunlun, Fakultas Perikanan, Universitas Pattimura, Poka-Ambon, Indonesia; in Makai, University of Hawai'i Sea Grant College Program, Vol. 21, No 7, July 1999)