First record of Rocinela aff. australis (Isopoda, Aegidae) in the Patagonian toothfish Dissostichus eleginoides (Pisces, Nothotenidae) from southern Chile

An isopod of the family Aegidae, provisionally referred to as Rocinela aff. australis Schiœdte & Meinert, 1879, is reported from the Patagonian tootfish Dissostichus eleginoides Smitt, 1898, from off the Biobio region, Chile. One specimen was collected, its body suboval, symmetrical, the dorsum weakly vaulted, stout, and with a few pits on the body. The specimen collected clearly belongs to the genus Rocinela and within that genus would most closely resemble Rocinela australis, but its actual specific status, whether an established species of the genus (and if so, which one) or possibly proving to be an as yet undescribed species, will have to await close examination by a specialist in marine isopod taxonomy. For the time being, we refer to the specimen as “Rocinela aff. australis”, since, compared with existing Rocinela spp., it matches best with that species both in general morphology and in geographical occurrence. This species, then, was reported until now only for the Strait of Magellan, Magellan region, and the southern Argentinean Atlantic coast. Thus, if the specimen would prove to really belong to Rocinela australis, then this report would constitute the most northern record of that species.

Gross morphology of the cephalic sensory canal pores in Patagonian toothfish Dissostichus eleginoides Smitt, 1898 from southern Chile (Perciformes: Nototheniidae)

This study describes the cephalic sensory canal pores of the Patagonian toothfish's juvenile and adult specimens (Dissostichus eleginoides) from southern Chile. Specimens exhibited four supraorbital, eight infraorbital, and five mandibular pores, followed by six preoperculars, one coronal pore, one supratemporal pore, and four temporal pores. Juveniles exhibited circular pores in the mandibular, infraorbital, and preopercular region. The first two supraorbital pores are circular, the third is rectangular, and the fourth triangular. The coronal pore is circular with a bifurcation; the supratemporal pore is rectangular. In adults, the first mandibular canal pore is circular, and the last four are elongated. The preopercular canal pores are elongated. The two first supraorbital canal pores are circular, unlike the third and fourth, which are rectangular. The coronal pore is rectangular without bifurcation, and the supratemporal pore has a T-shape. The jaw of juveniles does not present all mandibular canal pores; in the infraorbital region, the first five pores extend as a thin canaliculus, while the adjacent pores appear as longer canaliculi in adults. The differences could be related to changes in spatial distribution during larval, juvenile, and adult stages. Adult cephalic sensory canal pores may have an important role in detecting vibratory waves allowing them to capture their prey and perceive potential predators. Our results provide information regarding the cephalic sensory canal pores of the Patagonian toothfish that may stimulate future studies of this species' mechanosensory system.

Straddling the line: high potential impact on vulnerable marine ecosystems by bottom-set longline fishing in unregulated areas beyond national jurisdiction

Impacts of Patagonian toothfish bottom-set longline fishing on vulnerable marine ecosystems (VMEs) are examined in a licenced fishery and adjacent areas beyond national jurisdiction (ABNJ) lacking fishery management. VME taxa distributions were predicted using MaxEnt and compared to fishing footprints of ABNJ and licenced fleets. The ABNJ fishery footprint was almost twice as large as in licenced waters. Whilst the footprint of low fishing effort (0.0–3.4 h km−2) was similar between areas, footprints of medium (3.4–10.2 h km−2) and high (10.2–45.3 h km−2) fishing effort were 4 and 13 times greater, respectively, in ABNJ. Percent overlap of licenced fishing distribution on VME indicator taxa groups was low (6.45–9.82%) compared to the considerably higher (32.62–61.99%) percentage fishing overlap on VME indicator distribution in ABNJ. Our results show that, despite the main area of VME indicator taxa being found within jurisdictional waters, there are important VME habitats on the adjacent high-seas that are potentially highly impacted by unregulated fishing. This raises concerns regarding the potential for ABNJ fisheries to undermine domestic VME management where VMEs straddle managed areas and areas that are inconsistently managed or unmanaged. Management of VMEs would benefit from strengthening regional high-seas fishing governance and monitoring procedures.

Developing Single Nucleotide Polymorphisms for Identification of Cod Products by RAD-Seq

The increase in the rate of seafood fraud, particularly in the expensive fishes, forces us to verify the identity of marine products. Meanwhile, the definition of cod lacks consistency at the international level, as few standards and effective application methods are capable of accurately detecting cod species. Genetic fingerprinting is important for both certifying authenticity and traceability of fish species. In this study, we developed a method that combines DNA barcoding and the restriction-site associated DNA sequencing (RAD-Seq) approach for the identification of cod products. We first obtained 6941 high-quality single nucleotide polymorphism (SNP)s from 65.6 gigabases (Gb) of RAD-Seq raw data, and two sequences that contain SNPs were finally used to successfully identify three different cod product species, which are Atlantic cod (Gadus morhua), Greenland turbot (Reinhardtius hippoglossoides), and Patagonian toothfish (Dissostichus eleginoides). This SNP-based method will help us to identify the products, which are sold under the name of “Xue Yu” (Cod) in China, and works in parallel with existing fish identification techniques to establish an efficient framework to detect and prevent fraud at all points of the seafood supply chain.