“Cod population changed in response to intensified fishing”

“New research by scientists at the University of Iceland’s Research Centre of the Westfjords and their colleagues has revealed that the trophic niche of the Atlantic cod in Icelandic coastal regions remained stable for centuries, but changed in the 19th century alongside intensified fishing. It is likely that this reflects changes to both the age and size of the cod stocks, but also changes to marine food webs as populations fall due to extensive fishing and food chains shorten. The research was reported in Scientific Reports, a respected journal from the publishers of Nature. According to the authors of the study, the results underline the importance of conserving different migratory cod in Icelandic coastal regions, for example to boost the population’s resilience to environmental changes.

The research team included Guðbjörg Ásta Ólafsdóttir, biologist and director of the UI Research Centre of the Westfjords, and Ragnar Edvardsson, archaeologist at the Research Centre, along with their colleagues in Canada and Norway. 

Guðbjörg Ásta and Ragnar have worked together for many years on interdisciplinary research into fish bones, particularly cod, that they have excavated from ancient fishing stations in the Westfjords. The oldest bones are 1000 years old.  “The main aim of the research is to understand how changes in fishing and the marine environment have affected fish populations over the centuries. Using a data series spanning several centuries, we can establish a kind of baseline and try to estimate how extensive human exploitation could have affected marine ecosystems,” explains Guðbjörg Ásta. “

Read the full article here and the scientific article here.

Scientists Use Underwater Sounds to Rejuvenate Coral Reef Populations

Writing by Michelle Estevez

” The same way we might hear a specific song and experience a range of emotions, underwater speakers surprise researchers as unhealthy corals positively respond to their study. They placed underwater speakers to emit sound frequencies resembling what a healthy coral reef would sound like. Not only did this influence the unhealthy coral reefs to regenerate, but it also attracted a variety of fish to help reestablish degradation.

“We use loudspeakers to broadcast healthy soundscapes on experimental coral-rubble patch reefs for 40 days during a natural recruitment season (November–December 2017) on Australia’s northern Great Barrier Reef. We compare the developing fish communities on these acoustically enriched reefs with those on two categories of acoustically unmanipulated control reefs (with and without dummy loudspeaker rigs). We find that acoustic enrichment enhances fish community development within an important reef fish family, across a range of specific trophic guilds and at the level of the whole community,“ researcher Timothy A. C. Gordon mentions. ”

Article by Michelle Estevez for Educate Inspire Change, Read the full article here