Troubled waters ahead for marine life

Research from Victoria University of Wellington is investigating how coastal marine species may struggle with increasingly intense storms.

The common triplefin
The common triplefin.

The Intergovernmental Panel on Climate Change has forecasted that rising global temperatures will mean increased intensity of storms, including tropical cyclones with higher wind speeds, a wetter Asian monsoon and possibly more intense mid-latitude storms.

Victoria PhD student Becky Focht is looking to understand how species will cope with this kind of environmental disturbance by studying the common triplefin, a small marine fish found along shallow reefs and tidal pools throughout New Zealand. The triplefin experience some of the hardest impacts of big waves.

Her study has found that the triplefin eat a higher proportion of their prey in calmer conditions.

“Fish that live in more wave-exposed areas are bigger, but when there are more waves they eat significantly less prey,” says Ms Focht.

“I'm not yet sure why—but it does suggest that predators are more adversely affected by environmental stress than prey. This could have larger implications—a decline in predation rate or boost to populations of prey.”

Ms Focht says marine species have mechanisms to survive these events but human activity is pushing the limit.

“Humans rely on the oceans for food, transport, energy and recreation, but this takes a toll on the millions of marine species that live in them.

“It’s important that we understand what their coping strategies are to determine the long-term impacts of humans.”

The study was conducted at the Victoria University Coastal Ecology Laboratory (VUCEL) in Wellington’s Island Bay using a dump bucket system to simulate waves. The triplefin were fed food in buckets that were either experiencing wave events, had no waves, or had been in waves and then were moved to calm water.

Ms Focht’s research is supervised by VUCEL’s Professor Jeff Shima and supported by the Marsden Fund Council from Government funding, managed by the Royal Society of New Zealand.

Ms Focht presented her study this week at the joint 2016 New Zealand Marine Sciences Society and Australian Marine Sciences Association conference held at Victoria University’s Kelburn campus.

The four-day event included more than 350 international marine scientists discussing the latest advances in marine science, the competing demand for fisheries and other marine resources and the scientific work needed to help manage that demand, as well as how climate change is affecting the marine environment.