Albacore | European Tracking Network

Albacore

Thunnus alalunga

Image: planettuna.com ©

 

Species description and status: Albacore (Thunnus alalunga) is a mid-sized tuna that can weigh up to 20-30 kg as an adult. Thunnus alalunga lives in the Mediterranean, the North and South Atlantic and the Cantabrian Sea. There are also populations that inhabit temperate and tropical waters all around the world (Fig. 1). The Internatio- nal Union for Conservation of Nature (IUCN) Red list of Threatened Species classify albacore as Near Threatened (IUCN downloaded on 29 November 2019 \www.iucnredlist.org). The International Commission for the Conservation of Atlantic Tuna (ICCAT), in charge of the management of albacore in the Atlantic Ocean and adjacent seas, identifies three different stocks for albacore, North Atlantic, South Atlantic and Mediterranean, which according to the la- test evaluations are in good condition (ICCAT 2019) although in the Western Mediterranean abundance indices suggest a decline in the abundance for this species (Ingram et al. 2017).

Figure 1. Distribution of albacore with blue representing adult habitat and green representing spawning areas (planettuna.com).

 

Knowledge gaps: Knowledge gaps in their migration patterns still exist. Albacore is a migratory species although knowledge on their migration routes is still poor (Nikolic et al. 2017). Their migration patterns vary during the life history. Apparently, most alba- core in the Mediterranean never leave the area, traveling from east to west within the Mediterranean between feeding and spawning grounds but this has never been tested. The breeding season lasts about three months, from June or July through late August, although we don’t yet know the limits of all the areas where it takes place. There is no knowledge on the juveniles. In the North Atlantic Ocean, reproductive migrations are little known since there is little evidence to support the location of spawning grounds. Juvenile and immature albacore seem to be mainly distributed in the Northeast Atlantic during the summer and central and the southwest Atlantic in winter whereas when matu- re albacore seems to migrate from the North Atlantic to the tropical waters of the southeast sector. Migrations are also conducted by South Atlantic albacore. Migration between hemispheres has not been observed through tagging and is considered to be negligible (Arrizabalaga et al. 2007).

Telemetry tools: There are still many challenges regarding tagging for this species. Pop-up satellite archival tags (PSAT) are not suitable for small fish sizes. Although some satellite tagging has been conducted, the number of recovered tags is still quite limited and tracking are usually of short duration (Nikolic et al. 2017). Acoustic telemetry offers possibilities to characterize movement patterns for this species.

Benefits within the ETN: This species is a large migratory species that performs migrations across boun- daries. Collaborations across countries including joint research effort and international collaboration and sharing infrastructures is key to understand migration patterns, stock mixing, environmental thresholds, ontogenetic changes in species distributions as well as to estimate life-history traits at long-term scale.

Contacts: Patricia Reglero (patricia.reglero@ieo.es), Miguel Cabanellas Reboredo (miguel.cabanellas@ieo.es) and Francisco Abascal (francisco.abascal@ieo.es).

References:

  • Arrizabalaga H., Lopez-Rodas V., Costas E., González-Garcas A. (2007) Use of genetic data to assess the uncertainty in stock assessments due to the assumed stock structure: the case of albacore (Thunnus alalunga) from the Atlantic Ocean. Fish Bull 105(1):140–146
  • Ingram Jr G.W., Alvarez-Berastegui D., Reglero P., Balbín R., García A., Ale- many F. (2017). Incorporation of habitat information in the development of in- dices of larval bluefin tuna (Thunnus thynnus) in the Western Mediterranean Sea (2001–2005 and 2012–2013). Deep Sea Research Part II: Topical Studies in Oceanography, 140, 203-211.
  • Nikolic N., Morandeau G., Hoarau L., West W., Arrizabalaga H., Hoyle S., ... Williams A. J. (2017). Review of albacore tuna, Thunnus alalunga, biology, fisheries and management. Reviews in fish biology and fisheries, 27(4), 775-810.
  • Reglero P., Tittensor D. P., Álvarez-Berastegui D., Aparicio-González A., & Worm B. (2014). Worldwide distributions of tuna larvae: revisiting hypotheses on environmental requirements for spawning habitats. Marine Ecology Progress Series, 501, 207-224.