Multimethod approach to advance provenance determination of fish in stocked systems

Fish stocking occurs in aquatic systems for conservation purposes, to create or enhance recreational fisheries and to enhance wild-catch commercial fisheries. Identifying and quantifying the contribution of stocking efforts to wild populations is crucial to informing these management objectives. Provenance determination methods trade off accuracy, replicability, and costeffectiveness at fishery-relevant scales. We present and assess multiple methods for provenance determination using a case study of barramundi (Lates calcarifer) in the Dry Tropics region of northern Australia. A novel application of near-infrared spectroscopy (NIRS) is compared to two established methods for fish provenance, otolith microchemistry and genetic parentage analysis using microsatellites. The otolith microchemistry method was able to provide extremely high provenance resolution (>99% accuracy). The microsatellite parentage analysis method had a slightly lower overall accuracy (95%), likely as a result of genetic introgression in this region. Provenance determination using otolith NIRS had the lowest overall accuracy (76%). Once limitations regarding spectral noise, image resolution, and sample size are addressed, NIRS may have potential for costeffectively determining provenance in fish.

Automated summary

Fish stocking is important for conservation, recreational fishing, and commercial fisheries. This study compared three methods, otolith microchemistry, genetic parentage analysis, and near-infrared spectroscopy (NIRS), for determining the provenance of barramundi in northern Australia. Otolith microchemistry had the highest accuracy (>99%), while genetic parentage analysis had a slightly lower accuracy (95%) due to genetic introgression. NIRS had the lowest overall accuracy (76%), but shows potential for cost-effective provenance determination with improvements.