Larval Retention and Homing Behaviour Shape the Genetic Structure of the Bullet Tuna (Auxis rochei) in the Mediterranean Sea

Abstract

Background: The bullet tuna (Auxis rochei) is an epipelagic fish with a worldwide distribution that is highly targeted by fisheries. Genetic diversity and population genetics are good indicators of population structure and thus, essential tools for fisheries management. Knowing which factors (biotic and abiotic) might be shaping such structure is crucial for management plans. In the present study, we assessed the population structure of the bullet tuna in the western and central Mediterranean Sea. Methods: We used two types of genetic data: the mitochondrial DNA control region and seven microsatellite loci. The analysis of 431 sequences with a length of 386 bp from the mtDNA CR and the results from 276 individuals were genotyped by seven microsatellite loci. Results: Both types of markers coincided in showing significant genetic differences between an Iberian Peninsula–Strait of Gibraltar stock in comparison with a North African stock. Conclusions: We argue that this differentiation pattern is likely caused by reproductive strategies such as coastal spawning, larval retention, and natal homing behavior. These results should endorse the implementation of management plans for a resource that currently is not being managed. Thus, to ensure sustainability, these new policies should consider the presence of at least two genetically identified stocks.

Microplastic Contamination in Different Marine Species of Bintaro Fish Market, Indonesia

“…All three fish species usually feed on zooplanktons. However, A. rochei fish also feed on smaller fish, particularly anchovies and also crustaceans [92].…”

Length-weight relationship and condition factor of bullet tuna (Auxis rochei Risso, 1810) in the waters of Mamuju District, West Sulawesi Province, Indonesia

“…Bullet tuna, classified in the Scombridae family, is an epipelagic fish discovered in worldwide distribution, particularly in tropical waters (Sandoval-Ramírez et al 2020;Mardlijah et al 2021). Furthermore, it is a major target during fishing activities (Ollé-Vilanova et al 2022) and holds high economic value due to its nutritional content. This fish is considered a commodity for export to various countries such as the United States, Japan, Thailand, Italy and Saudi Arabia (Baliwati and Putri 2012) because it possesses high protein content, essential amino acids, unsaturated fats crucial for nutritional needs, growth enhancement, cognitive benefits, cholesterol reduction, and various health advantages (Nepomuceno et al 2020;Rampazzo et al 2020;Wibowo et al 2020;Artetxe-Arrate et al 2021;Husain et al 2021;Bintoro et al 2023).…”

Genetics and Biotechnology—The Section Editor-in-Chief’s View

“…Campbell et al [1] showed very high levels of genetic differentiation among populations of Shoshone sculpin Cottus greenei in the Hagerman Valley of Idaho in the western United States; hence, preserving the genetic diversity of this species will require the protection and preservation of multiple isolated populations. Ollé-Vilanova et al [2] showed significant genetic differentiation between an Iberian Peninsula-Strait of Gibraltar stock and North African stocks of bullet tuna Auxis rochei, and suggested that distinct management regimes should be implemented for these two genetic stocks. Nguyen et al [3] found that populations of giant mottled eels A. marmorata in central Vietnam were genetically similar to eels found in North Pacific populations, while those from farther south resembled South Pacific populations, highlighting a combination of differentiated stocks and thus informing fishery management.…”