But it needs nutrient-rich cool waters where they go on a feeding frenzy to grow from one-millimeter paralarvae specks to enormous predators of over 1.2 meters long. The squid seeks warm waters near the equator to spawn its clusters of neutrally buoyant eggs. Catching these squids without knowing that their genetic contribution is different, is also very risky."īoth warm tropical waters and the cooler Humboldt current, which runs from Tierra del Fuego at the southernmost tip of the South American mainland upwards to the northern coast of Peru, play a role in the Humboldt squid's life cycle. "From our study, it is also clear that the squids caught by different countries also belong at least two different populations, with likely different genetic contribution for the next generation. In such a situation, there is a risk of having a genetic erosion with a smaller number of squids which are also less likely to adapt rapidly to the changing environment," he remarked. By doing so, the genetic contribution of the offspring every year will also clearly fluctuate. "Countries fishing this squid have established catch quotas with no consideration that the total amount varies from year to year, and that the amount of squid caught influences the number of squids next year. But the study found this approach to be ineffective, especially as catch restrictions are absent in international waters on the squid's migration path. To ensure sustainable fishing, countries in South America where the squid is traditionally found have established yearly catch quotas. Our results suggest that rather than independent marine policies from each country, the sustainability of this squid requires an international marine policy," Sanchez said. "In our study, we identify at least two genetic stocks co-distributed in the north and southern hemisphere of the Eastern Pacific Ocean. The equator doesn't serve as a natural barrier to separate the different genetic stocks of these fast swimmers risking capture by different fishery fleets along their migration route. But in Humboldt squids, DNA markers showed no north-south divide. The team found that Humboldt squids could trace back their population to three historical matrilineage that spread out during the late Pleistocene and that the species has at least two contemporary genetic stocks homogeneously co-distributed in the northern and southern hemispheres.ĭifferent genetic stocks within a species are usually defined by where they feed and breed. Memoirs of Museum Victoria 81: 1–23.Hiroshima University marine biologist Gustavo Sanchez led a team of researchers to find out the genetic structure of the Humboldt squid population in the Eastern Pacific Ocean using two types of DNA markers - the mitochondrial ND2 gene and nuclear microsatellite loci. Two new genera and species of sepioline squids (Cephalopoda: Sepiolidae) from Australia. The discovery of these two new taxa indicates that the present definition of Sepiolinae needs to be broadened to accommodate these two new genera. The bursa copulatrix is in the left side of the female body, as in other known sepioline squids. Amutatiola macroventosa is characterised by the absence of a hectcotylised arm in mature males instead, it possesses many enormously enlarged suckers on some of the arms of the males. All other known sepiolinids have copulatory organs in the left side of the body. the hectocotylised arm in the males and the bursa copulatrix in the females) in the right side of the body. Dextrasepiola taenia is characterised by having copulatory organs (i.e. Two new genera and species of sepioline squid (Cephalopoda: Sepiolidae) are described from Australian waters.
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