The waters off southeastern Australia are experiencing rapid warming, causing a proliferation of long-spined sea urchins. Although it was initially thought that lobsters played a key role in managing these sea urchins, a recent study has overturned that assumption and called into question management strategies for marine ecosystems.
South-eastern Australia’s waters are warming almost four times faster than the global average. Among the remarkable results of this warming, scientists have noted the proliferation of sea urchins, native to the temperate waters of New Zealand.WellsWells Why is this a problem in the South? Well, because this long-spined sea urchin (Centrostephanus rodgersii)) Kelp forests graze on giant brown algae, leaving devastated habitats in their wake.
Faced with this challenge, scientists have tried to reduce their spread by focusing on lobsters, the main predators of these sea urchins. “Hypothesized,” because a recent study revealed that sharks play a previously underestimated role in this marine ecosystem.
Observations of Heterodontus galetes sharks feeding on sea urchins. © University of Newcastle, Australia
A hidden camera reveals an overlooked truth at night…
By filming interactions between lobsters and sea urchins using night cameras, researchers discovered that it is sharks, not lobsters, that eat the majority of sea urchins: the crested sleeper shark (Heterodontus galeatus) and Port Jackson (Heterodontus portus jacksoni) approximately 45% of sea urchins were eaten during observation nights, compared to only 4% for lobsters.
According to these findings, lobsters are no match in the war against sea urchin attacks when faced with the abundance and strength of sharks. However, it remains to be determined whether this will be sufficient to prevent their spread in an uncontrolled natural context! In fact, it is not surprising to find the intended predator is deliberately lured to one. baitbait. Would such results have been obtained in an artificial environment? The environment in which the factors AbioticAbiotic As changes in winds and salinity also affect sea urchin populations…
