Ein sehr persönlicher Bericht über das Forschungsschiff Poseidon, das Ende Januar 2020 von Sea-Watch gemeinsam mit dem Bündnis United4Rescue erstanden werden konnte, im Februar diesen Jahres auf den Namen Sea-Watch 4 getauft wurde und nun im Mittelmeer im...
Der Rote Thunfisch stirbt aus – Neue Studie des IUCN zeigt bedrohliche Bestands-Situation
Zum ersten Mal wurden die Fischarten einer ganzen Fischfamilie (Scombridae = Makrelen und Thunfische) von der Weltnaturschutz IUCN nach wissenschaftlicher Analyse als besonders gefährdet eingestuft. Nach Ansicht der Forscher steht es besondes schlecht um die großen Räuber wie dem Roten Thunfisch, da die Überfischung unvermindert anhält. Nur durch Schutzgebiete und strikteren Fangquoten hat diese Fischart eine Zukunft in den Meeren.
Increased protection urgently needed for tunas
For the first time, all species of scombrids (tunas, bonitos, mackerels and Spanish mackerels) and billfishes (swordfish and marlins) have been assessed for the IUCN Red List of Threatened Species. Of the 61 known species, seven are classified in a threatened category, being at serious risk of extinction. Four species are listed as Near Threatened and nearly two-thirds have been placed in the Least Concern category.
The results show that the situation is particularly serious for tunas. Five of the eight species of tuna are in the threatened or Near Threatened IUCN Red List Categories. These include: Southern Bluefin (Thunnus maccoyii), Critically Endangered; Atlantic Bluefin (T. thynnus), Endangered; Bigeye (T. obesus), Vulnerable; Yellowfin (T. albacares), Near Threatened; and Albacore (T. alalunga), Near Threatened.
This new information will be invaluable in helping governments make decisions which will safeguard the future of these species, many of which are of extremely high economic value, and is a timely input for the 3rd Joint Meeting of the Tuna RFMOs (Regional Fisheries Management Organizations) being held in La Jolla, California, July 11-15.
This is the first time that fishery scientists, ichthyologists and conservationists have come together to jointly produce an assessment of the threats facing a commercially important group of fishes, says Dr Bruce B. Collette, Chair of the IUCN Species Survival Commissions (SSC) Tuna and Billfish Specialist Group, Senior Scientist of the NOAA National Marine Fisheries Service, and lead author of the paper.
There is growing concern that in spite of the healthy status of several epipelagic fish stocks (those living near the surface), some scombrid and billfish species are being heavily overfished, and there is a lack of resolve to protect against overexploitation driven by high prices. Many populations are exploited by multinational fisheries whose regulation, from a political perspective, is exceedingly difficult.
All three bluefin tuna species are susceptible to collapse under continued excessive fishing pressure. The Southern Bluefin has already essentially crashed, with little hope of recovery, says Dr Kent Carpenter, Professor at Old Dominion University, manager of IUCNs Marine Biodiversity Unit and an author of the paper. If no changes are made to current fishing practices, the western Atlantic Bluefin stocks are at risk of collapse as they are showing little sign that the population is rebuilding following a significant reduction in the 1970s.
Three species of billfishes are in threatened or Near Threatened categories: Blue Marlin (Makaira nigricans), Vulnerable; White Marlin (Kajikia albida), Vulnerable; and Striped Marlin (Kajikia audax), Near Threatened.
Most of the long-lived economically valuable species are considered threatened. They mature later than short-lived species and their reproductive turnover is longer, and as such recovery from population declines takes more time. As these scombrids and billfishes are at the top of the pelagic food web, population reductions of these predators may cause significant negative effects on other species that are critical to the balance of the marine ecosystem and that are economically important as a source of food.
The future of threatened scombrids and billfishes rests on the ability of RFMOs and fishing nations to properly manage these species. Southern and Atlantic Bluefin populations have been so reduced that the most efficient way to avoid collapse is to shut down the fisheries until stocks are rebuilt to healthy levels. However, this would cause substantial economic hardship and hinder the ability of RFMOs to control fishing because of the increased incentive for illegal fishing that would be created under these circumstances.
Temporarily shutting down tuna fisheries would only be a part of a much needed recovery programme. In order to prevent illegal fishing, strong deterrents need to be implemented, says Jean-Christophe Vié, Deputy Director, IUCNs Global Species Programme. This new study shows that there is an urgent need for effective management. Scientific findings should not be discarded in order to maintain short-term profit. Marine life and jobs for future generations are both at stake.
The recovery of fish stocks is possible through reducing fishing-induced mortality rates to well below the maximum sustainable yield (MSY), as shown in the case of the highly valued eastern population of the Atlantic Bluefin. Recently exploited at three times the MSY, a decrease in the total allowable catch and stricter monitoring and compliance measures have led to recent catch reductions of almost 75% over the past few years. This will enable the species to recover to sustainable levels as long as the current fishing controls are maintained.
Science paper High Value and Long-Lived: Double Jeopardy for Tuna and Billfishes
The tuna and billfish assessments
The tuna and billfish assessments are a part of the Global Marine Species Assessments mission to complete more than 20,000 marine species assessments for inclusion on the IUCN Red List of Threatened Species. The Global Marine Species Assessment Unit (GMSA), or Marine Biodiversity Unit, is a joint initiative of IUCN and Conservation International. The GMSA is headquartered in the Department of Biology at Old Dominion University in Norfolk, Virginia, and is largely enabled by the generous support of the New Hampshire Charitable Foundation and Tom Haas.
To complete the tuna and billfish IUCN Red List assessments, the GMSA collaborated with a wide diversity of international scientists who represent Fisheries Management Organizations, international conservation organizations; government agencies, universities, and independent fisheries research institutions. IUCN Red List Workshops and finalization of results for tunas and billfishes were made possible by the generous support of Tom Haas and the New Hampshire Charitable Foundation, Conservation International, Lenfest Ocean Program, International Seafood Sustainability Foundation, International Game Fish Association, Instituto Chico Mendes de Conservação da Biodiversidade, Academia Sinica, Taiwan Marine National Park Headquarters, Instituto del Mar del Perú, and CIMAR- University of Costa Rica.
Complete results of the tuna and billfish species assessments will be published on the IUCN Red List of Threatened Species in November 2011. As of July 7, 2011, draft assessments can be found at: http://sci.odu.edu/gmsa/about/tunas_billfishes.shtml
The IUCN Red List threat categories
The IUCN Red List threat categories are as follows, in descending order of threat:
Extinct or Extinct in the Wild
Critically Endangered, Endangered and Vulnerable: species threatened with global extinction
Near Threatened: species close to the threatened thresholds or that would be threatened without ongoing specific conservation measures
Least Concern: species evaluated with a lower risk of extinction
Data Deficient: no assessment because of insufficient data
Critically Endangered (Possibly Extinct): this is not a new IUCN Red List Category, but is a flag developed to identify those Critically Endangered species that are in all probability already Extinct but for which confirmation is required, for example, through more extensive surveys being carried out and failing to find any individuals.
The IUCN Red List of Threatened Species
The IUCN Red List of Threatened Species (or the IUCN Red List) is the worlds most comprehensive information source on the global conservation status of plant, fungi and animal species. It is based on an objective system for assessing the risk of extinction of a species should no conservation action be taken.
Species are assigned to one of eight categories of threat based on whether they meet criteria linked to population trend, population size and structure and geographic range. Species listed as Critically Endangered, Endangered or Vulnerable are collectively described as Threatened.
The IUCN Red List is not just a register of names and associated threat categories. It is a rich compendium of information on the threats to the species, their ecological requirements, where they live, and information on conservation actions that can be used to reduce or prevent extinctions.
The IUCN Red List is a joint effort between IUCN and its Species Survival Commission, working with its Red List partners BirdLife International; Botanic Gardens Conservation International; Conservation International; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; Wildscreen; and Zoological Society of London.
IUCN, the International Union for Conservation of Nature, helps the world find pragmatic solutions to our most pressing environment and development challenges by supporting scientific research; managing field projects all over the world; and bringing governments, NGOs, the UN, international conventions and companies together to develop policy, laws and best practice.
The world’s oldest and largest global environmental network, IUCN is a democratic membership union with more than 1,000 government and NGO member organizations, and almost 11,000 volunteer scientists and experts in some 160 countries. IUCN’s work is supported by over 1,000 professional staff in 60 offices and hundreds of partners in public, NGO and private sectors around the world. IUCN’s headquarters are located in Gland, near Geneva, in Switzerland.