Remarks on the rearing of gobies(Pomatoschistus minutus andP. lozanoi) for experimental purposes
- M. Fonds1
© Biologischen Anstalt Helgoland 1970
1. During an investigation on the numerical variations in vertebral counts ofPomatoschistus minutus (33 vertebrae) undP. lozanoi (32 vertebrae), larvae of these closely related gobies were reared from eggs to young fish.
2. From 1963 to 1965, rearing was not very successful; it yielded 34 to 220 young fish with estimated survival rates of the larvae between 2 and 10 %. Rearing methods were improved and yielded 66 % survival in 1966; 1,585 young fish were reared from 2,400 larvae; in some experimental groups survival was approximately 90 %.
3. The seawater of the closed rearing system used in 1966 was treated with ozone; antibiotics were added in concentrations of 20 I.U. penicillin G + 10µg streptomycin per ml seawater.
4. The larvae were fed natural zooplankton, washed and sieved through plankton gauze of different mesh sizes.
5. A description is given of the rearing method used in 1966 and the development ofPomatoschistus lozanoi larvae.
6. Growth rates of the larvae were in the order of 21 to 39 mm increase in length per 100 days at 14° to 16° C. The larvae changed to bottom life 31 days after hatching at a total length of approximately 12 mm.
7. Eggs ofPomatoschistus lozanoi (32 vertebrae), incubated at temperatures of 10° to 20° C until attainment of the “eyed egg” stage, yielded offspring (hatched and raised at 16° C) with a mean vertebral number of 31.90 (n=1,585) and a variation in mean vertebral number for the various experimental groups from 31.73 (n=206) to 32.13 (n=122 vertebrae). Crossings of fishes with 32 vertebrae and 33 vertebrae yielded offspring with a mean vertebrae number of 32.44 (n=34), 32.55 (n=107) and 32.65 (n=118), respectively.