Harpij 3 2007

 

 

 

 

 

Muskoxen EEP

 

Bas Martens

GaiaPark

 

The muskoxen EEP was established in 1985. This EEP, one of the earliest established, has always been coordinated by Bengt Holst of Copenhagen Zoo. Two subspecies of muskoxen  are recognized: Ovibos m. moschatus from Alaska, and O. m. wardi from Greenland. The two subspecies cannot be separated visually, and there is currently no DNA test available to distinguish subspecies. It is thus necessary to classify them based on place of origin. Initially only O.m. wardi was managed intensively in the EEP; hybrids and O.m. moschatus were lumped together in a loosely managed group. The managed O. m. wardi population was small and becoming inbred, thus four wild-caught males were added to the population in 1998. Breeding has not been successful enough to counter mortality, between 1990 and 2005 there were 211 muskoxen of  both subspecies born , of which 97 did not survive. During the same period 115 deaths in the population occurred, offsetting the gain of 114 reared young.

 

Because there were no O. m. wardi available, Gaiapark in the Netherlands decided to work with O. m. moschatus, and imported 0.3.0 from St. Felicien Zoo in Canada in 2004. A male was received from Tierpark Berlin in 2005. All three females became pregnant in 2006;  “Inuit” had a miscarriage early on, “Nanouk” had a still born young and “Namippunga”  produced a healthy female calf.  The mother refused to nurse the calf after two weeks, probably because of a medical problem, and the calf had to be hand-reared. As the calf had been mother-nursed for two weeks it initially took three people to get any milk into her using a bottle. After three weeks she came to the fence to receive her milk, and she grew well, gaining approximately 300 g per day, similar to what mother- nursed muskoxen gain.

 

 

The Tiger fish at Antwerp Zoo 

 

Wilfried Van der Elst

Zoo Antwerpen

 

While saltwater fish may be more colourful then freshwater fish, freshwater fish are more interesting behaviourally. Antwerp Zoo specializes in fresh water fish, and wanted to acquire tiger fish. There was little information to find on these animals, and even experts on African fish knew little. A group of  25 Hydrocinus vittatus  ordered from an importer arrived in November 2005 after three weeks in quarantine at the importer. The tiger fish were 10 to 12 cm in length and came from the area around Kinshasa. They were immediately released in a large basin and fed with small smelt. A few of the tiger fish grew faster than the rest, and sometimes mistakenly  bit into a smaller tiger fish during feeding frenzies. The solution was simple: to cut the smelt in small pieces so that all the tiger fish could eat at the same time. As the tiger fish increased in size the size of the food offered was increased. The tiger fish grew rapidly, from 10 cm to just under 40 cm in one year with normal feeding levels. The tiger fish also eat ink fish and shrimp, but fish remain their favourite food. They have to be fed daily to keep their aggression level low. As they have grown their aggression has decreased, but  bite have become more serious because the teeth have grown large. Their wounds heal amazingly  quickly however.

 

The tiger fish are very fast and manoeuvrable in their tank. Their hydrodynamic form and their speed make them perfect predators. These “ Benga”, as the local Africans call them, even have a reputation for attacking crocodiles. Because they can easily jump 2 m out of the water it was necessary to fashion an “aviary”around their tank at Antwerp Zoo. It is not clear which other fish they are most closely related to. They may be a primitive tetra (in the family Characidae) or a primitive member of the Alestidae. While tiger fish are extremely interesting, they are not suited for the hobbyist, and hopefully will not come into the commercial circuit.

 

 

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