Reseeding of Haliotis iris in a customary fisheries context

Reseeding;paua;Marine reserve;Fisheries;Taiapure;mataitai;customary fisheries;abalone

Gillies, Tasman Turoa ; Hepburn, Christopher ; Lokman, Mark

University of Otago

关键词: Reseeding;    paua;    Marine reserve;    Fisheries;    Taiapure;    mataitai;    customary fisheries;    abalone;   

Others  :  https://ourarchive.otago.ac.nz/bitstream/10523/5351/1/GilliesTasmanT2014MSc.pdf

美国|英语

来源: Otago University Research Archive

【 摘 要 】

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 correctly assigned individuals ranging from 67.1 – 98.6%. The results from the use of the microsatellite markers to identify the origin of individuals indicate that it is not 100% reliable and this should be considered before applying its use in future reseeding efforts.The results suggest that the use of reseeding in customary management areas requires further investigation. This will help to improve the survival of the released individuals. The implementation of genetic monitoring at the hatchery level is key to minimising genetic risks. The use of microsatellite markers, as used in this study, to identify released animals will produce unreliable results when attempting to identify animals in the future. Overall, the use of reseeding in the East Otago Taiāpure and the Punawai O Tōriki Mātaitai indicated that reseeding methods need to be refined and reviewed to assess the success of reseeding in customary areas. It was seen that genetic monitoring is useful tool to identify and minimise genetic risks when reseeding. It is recommended that it should be used in all stock enhancement programs in general.