New approach in creating pikeperch broodstock

NAIK HAKI investigated a lot of approaches to create a pikeperch broodstock. According to Uros Ljubobratovic one of the most promising approach is a combination of keeping the animals first outdoor followed by stocking in indoor recirculated aquaculture system (RAS).

This is a testimonial from Uroš Ljubobratović.

Background

The reproductive biology of pikeperch was the main aspect of my research interest in last years with the main goal to effectively control its reproductive cycle. Luckily, at NAIK HAKI we had a project working on exactly this issue! Since, I performed various reproductive trials on different sort of breeders – wild and feed-eating, feed-eaters kept fully in RAS, feed-eaters kept in outdoor conditions, both extensive and intensive, reproductively inexperienced and experienced fish. After all the obtained results, experiences and observations, I was able to create an image of how to produce the perfect breeder.

Photo: Trials on reproductive performance in pikeperch were often at NAIK HAKI recently (photo by Flórián Tóth)

A perfect breeder

It should be a fish which is under seasonal cycle as soon as possible after hatching. If so, in some 3-4 seasons, this fish should become the breeder! Doing it in uncontrolled outdoor conditions is rather simple task, however, after several trials in fully controlled conditions I concluded this might be a rather difficult, challenging, risky and finally costly task. So, what could be the solution?

Photo: Females pikeperch at the time of hormonal treatment, eleven months following the transport from outdoor to fully controlled climate room. (photo by Flórián Tóth)

Trial set

First what appeared to my mind is – produce the perfect broodstock outdoor and then shift their cycle. A stock of 3-month-old fingerlings was stocked in IPCS system in July 2016. Further on, they were kept in these outdoor intensive conditions fed with dry feed exclusively. In November 2019, in females’ stage of late vitellogenesis, breeders were transported to the quarantine system and after veterinarian inspection were further stocked in the fully controlled climate-control RAS room with aim to shift its reproductive cycle from natural where spawning usually occurs in spring, to artificial where the spawning should occur in autumn, thus in 12 months following the transport.

Photo: Experimental broodstock and NAIK HAKI climate control room. (photo by Flórián Tóth)


Final part

Total duration of the trial was 12 months and there are still many samples and data to process, however its finale, the artificial reproduction was performed in October 2020. The main outcome which can be already stated and is perhaps the most important for farmers is – it really works! The quality of eggs obtained in one treatment group is among the best and most stable ever obtained at our institute including all reproduction batches.

Photo: All females yielded the eggs of such quality in terms of deformation upon cortical reaction and possible implementation (photo by Flórián Tóth)

 

Our opinion is that this might be very useful for broodstock management in RAS farms. Instead of growing the future breeders in fully controlled conditions, young candidates could be raised in semi-controlled conditions under the natural photo-thermal schedule finally growing up to the broodstock producing gametes in regular season. Upon the evaluation of reproductive performance, the best performing breeders could be shifted out-of-season, thus reducing the number of breeders for climate control rooms, enabling them to be smaller and economically feasible yet maintaining the low risk of failure.

For more information, contact Uroš Ljubobratović via uros.ljubobratovic@haki.naik.hu

published 02 December 2020