Fish Breeding Program at Hofstra University
Systems were constructed and a protocol implemented for the captive culture of gobies and other small marine fish species. To date,14 species, including 6 gobiids have spawned and been reared at our facility. The relatively inexpensive procedure described here has become a valuable tool for gathering developmental data to be used in the reorganization of gobiid systematics.
Comprised of approximately 2000 species, the Gobiidae is the largest family of marine fishes (Robins et at.,1987) and probably one of he largest vertebrate families. Gobiids are an important component of the aquarium fish industry throughout the world (Burgess et al., 1988) and in some cultures, are used as food (Fishbase, 2000).
At the Hofstra University Marine Laboratory in Hempstead, New York we have constructed systems and initiated a protocol for the captive cultivation of gobiids and other small marine fish species. Presently two broodstock systems capable of holding a total of 36 spawning pairs of fishes are in place. Although a 300-gallon larval system of cylindrical polyethylene tanks is under construction, larvae are currently being raised in 10-gallon aquaria. The rotifer, Brachionus plicatilis , is used as a first food, followed by nauplii of Artemia salina , then commercially prepared dry foods. The marine alga, Isochrysis galbana is used as a water conditioner and as food for the zooplankton.
Two systems, system A and system b (Figures 1 and 2, respectively), were built to hold pairs of mature fishes. System A consists of 7 10-gallon aquaria and 6 29-gallon aquaria. System B contains 5 10-gallon aquaria and 12 5-gallon aquaria. The number of aquaria in each system was determined by available space on the support structures that were scavenged for the project. The filtration in each system is comprised of an open-cell foam prefiler, a 2100 cubic centimeter trickle filter with plastic Bio-balls and a 150cm x 10cm, cylindrical, acrylic protein skimmer (figure 3). All compenents in each system are powered by an 1800 gallon per hour (gph), Mag-drive submersible pump. All return lines and drain lines are constructed of standard PVC pipe and fittings (figure 4). Water flow to each tank is controlled by a 1/2 inch PCV ball valve. A lustar breeder box is placed in each 10-gallon tank allowing us to keep 2 spawing pairs in those tanks without danger of territorial aggression.
Broodstock specimens were collected by the authors in Puerto Rico, Panama, Honduras, Florida, and New York, or obtained from aquarium retail stores.
In preparation for hatching, a 10-gallon larval rearing tank is filled with synthetic seawater (Instant Ocean) at a salinity of 30 parts per thousand (ppt) and gently aerated through a ceramic airstone. Then 1 liter of concentrated Isochrysis and approximately 40,000 rotifers, or enoughto bring the concentrationto 10 rotifer/ml, are added. After hatching, the rotifer concentrations is estimated daily by removing 1 ml of water and counting individuals in a depression slide, using the 40x magnification of a dissecting microscope. 1 liter of Isochrysis is added to the tank daily, and rotifer concentrations are maintained at approximately 10/ml.
Most of the gobiids we have worked with reach metamorphosis around day 30 post-hatch, although some species such as Tigrigobius puncticulatum and Coryphopterus personatus can take 50-60 days. We define metamorphosis as a significant increase in pigmentation, usually coupled with setlement from a pelagic to a benthic mode of existence. Around the point of metamorphosis, dry feeds are introduced to the diet and become the exclusive food within 3 weeks. At this point, juveniles from various rearing tanks are consolidated into 29-gallon tanks in system A. During the larval period 2 larvae are removed from each rearing tank daily for observations of osteological development and photographing.
Results and Discussion
As of this writing, 14 marine fish species including 6 species of goby, have been spawned and reared in our systems (table 1). Our ability to adapt commercial aquaculture techniques to a laboratory setting has enabled us to look at early development as a source of character data that has not been previously used in the structuring of gobid systematics.
Burgess, Warren E, Herbert R. Axelrod and Raymond E. Hunziker, III. 1988. Atlas of marine aquarium fishes, second edition. TFH Publications.
Fishbase.org. 2000. Family information: Gobidae.
Hoff, Frank H. and Terry W.Snell. 1987. Plankton culture manual. Florida Aqua Farms. Dade City, Florida.
Moser, H.G. 1983. Ontogeny and systematics of fishes. Special publication Number 1 of the American Socity of Ichthyologists and Herpetologists.
Robins, C.R., G.C. Ray and J. Douglas. 1986. A field guide To Atlantic coast fishes. Houghfin Mifflin Company, Boston.
Van Tassell, James L. 1998. Phylogenetic relationships of the Gobiid genus Gobiosoma with commentson their relationships to other genera in the tribe Gobiosomini. PhD dissertation submitted to the City University of New York.
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