AbstractsBiology & Animal Science

Reseeding of Haliotis iris in a customary fisheries context

by Tasman Turoa Gillies

Institution: University of Otago
Year: 0
Keywords: Reseeding; paua; Marine reserve; Fisheries; Taiapure; mataitai; customary fisheries; abalone
Record ID: 1299550
Full text PDF: http://hdl.handle.net/10523/5351


Globally, there is an increasing demand for fish which is accompanied by global trends of declining wild fish stocks. Fisheries managers are looking for alternative techniques to increase production and to more effectively manage stocks. Reseeding is a technique aimed at increasing wild abalone populations via the addition of juveniles that have been raised in aquaculture, often on a large scale. Large scale releases of hatchery reared animals into the wild have the potential to cause adverse genetic effects on the recipient wild population. These adverse effects can often result from events that occur at the hatchery where the animals were bred and reared. If appropriate numbers of brood stock and gamete mixing protocols are not employed at the hatchery, then the hatchery reared animals may exhibit inbreeding depression. In addition to this, a mass release of such individuals can result in outbreeding depression in the wild recipient population. In order to minimise the genetic risk and identify hatchery reared animals post-release procedures for genetic monitoring and genetic identification should be in place. There is interest from commercial, recreational and iwi groups in New Zealand in the application of abalone reseeding. The interest comes is due to the potential for use in replenishing and sustaining stocks of the blackfoot abalone, Halioti iris. In April 2013, reseeding of juvenile H. iris was undertaken in the East Otago Taiāpure and the Punawai O Tōriki Mātaitai, two customary management areas in Otago, New Zealand. This reseeding event has been used as a case study to assess the use of reseeding into customary areas. The survival of the reseeded animals was tracked. The released animals were compared in length and number to the resident wild juvenile H. iris. The DNA microsatellite markers were used to determine the suitability of individuals for reseeding by analysing the genetic diversity and genetic population structure of the hatchery reared and wild juvenile H. iris. The use of DNA microsatellite markers was also examined for use in distinguishing between wild and hatchery animals post-reseeding. An estimated 125543 ± 17405 (1 SE) juvenile H. iris were released in the East Otago Taiāpure and the Punawai O Tōriki Mātaitai. The survival of the released animals was very low (<0.05%). There was no difference between the number of wild and reseeded juvenile H. iris seen at the reseeding sights after the release. The pre-reseeding and post-reseeding animals were not significantly different in length, but both differed significantly from the wild juveniles present. The genetic monitoring concluded that there was reduced genetic diversity in the hatchery populations compared to the wild H. iris. There was genetic population differentiation between two of the hatchery populations and the wild populations. The use of microsatellite markers to identify the hatchery populations worked best when the hatchery populations were compared to a combined wild population. However, there was still variable success with…