The Reproductive Biology and Spawning of Zebrafish in Laboratory Settings - Zebrafish: Methods for Assessing Drug Safety and Toxicity - page 6

Figure 1.2 Representative examples of zebrafish spawning technology. (a) In-tank breeding
container. (b) MEPS. (c) Typical static tank mating tank with insert.

has a number of drawbacks, including the fact that all fish in the housing tanks where
breeding is taking place must be either in the crossing cage or transferred to other
tanks so that eggs are not cannibalized. This requires extensive handling of animals,
offsetting one inherent advantage of the in-tank breeding methodology. Second, in
most cases, flow of clean water into tanks must be either shut off or reduced to prevent
spawned eggs from being flushed out of the tanks. There may be means by which to
collect these eggs when flow remains on, but if not, another strength of the in-tank
system is taken away when using this method. Finally, although various cages of this
type are commercially available, they are often system vendor specific, which limits
their applicability to the users of the associated system.
The most recent development in in-tank breeding technology is theMass Embryo
Production System (MEPS

), designed by Aquatic Habitats, an aquatic animal
housing systemmanufacturer. TheMEPS is a large spawning vessel, with a holding

capacity of 80 or 250 L, which can be plumbed directly into any existing recirculating
or flow-through system. The MEPS , which can house large populations (up to 1000

or more) of breeding fish, contains one or more spawning platforms, which are
specially fabricated funnels capped with plastic mesh screens that can be located at
various depths inside the vessel (Fig. 1.2b). When the spawning platforms are placed
inside the vessel, fish breed over and on the platforms, and spawned eggs fall through
the mesh into the associated funnels. The eggs are then pumped through an attached