Fishing nets. Stock media provided by Frank Gartner / Pond5

Commercial fishing boats have negatively impacted wild fisheries with nets that don’t discriminate between size class and the reproductive maturity of fish species. Most boats are equipped with technology that target a school of fish, with one catch potentially wiping out the next generation, leaving some populations depleted or completely destroyed. Recovery takes a while, and the disappearance of key stone species over time affects the collective ecology and abundance of marine animals and plants. Each year approximately 640,000 tonnes of fishing gear and nets are discarded by the fishing industry. Is it game, set and match in the world’s oceans?

Tangled fishing gear is encrusted with a red sponge, and used by tropical fish as habitat. Stock media provided by Ethan D / Pond5

Conservation of the Great Barrier Reef along the east coast of Australia with the GBR Marine Park has made a huge difference to the abundance of tropical reef fish and other marine life. ‘No take’ and ‘take’ zones guide recreational and commercial fishers to places where fish and crabs etc., can be legally caught.

The ‘no take’ zones allow animals to breed without fishing pressures, which in turn increases the numbers of wild fish available in ‘take zones’. Marine Parks around Australia’s coastline and worldwide, continue to positively affect marine life abundance and diversity, supported by community awareness campaigns.

More people are investing their expertise and knowledge into aquaculture as a sustainable alternative to the wild caught fisheries. There are a range of methods used to breed fish, crustaceans, shellfish and algae for restaurants and the markets, in fresh water or saltwater aquaria/ponds. Similar to any competition, aquaculture has encountered its fair share of criticism; but improved technologies have made it more commercially viable.

A stingray swims injured and tangled by fishing gear in the Mediterranean Sea. Stock media provided by dam@seaphotoart.com / Pond5

Nets abandoned by fishing crews, continue to make a big haul at sea though, fatally trapping whales, dugongs, fish, crocodiles, sea birds, sharks, seals and dolphins, as they drift along the oceans currents. Recently, a spate of shark attacks along beaches prompted the introduction of drum lines in New South Wales to curb the risk to surfers and swimmers. Drones equipped with cameras are currently being trialled to alert authorities if shark activity is observed along beaches. This method combined with drum lines is considerably less threatening to marine species, compared to the use of nets.

Turtles and seabirds recurrently swallow or are entangled by fishing line, tackle, plastic debris and nets, despite efforts led by community groups like Clean Up Australia to remove marine debris and rubbish in general. One of the hotspots for discarded fishing nets is the Gulf of Carpentaria in Australia’s north. Seven species of marine turtle are listed as threatened, including the Hawksbill, Green, Olive Ridley, and Flatback turtles. Ghost nets are the common cause of death.

Dead turtle entangled in fishing nets on the ocean. Stock media provided by http://www.mclubber.ru / Pond5

Ghost nets are a serious environmental hazard, not just to animals, but also to anyone going out on a boat. A net can jam an engine. If you spot an injured animal, please contact a wildlife rescue group or a veterinary clinic for assistance; and safely throw discarded nets or tackle into a bin. It’s just one thing to do, but if we all do it, this deadly game out at sea might be over for good.

Written by Gabrielle Ahern


Salty Wave Blue – Into all things ecology.

Follow @SaltyWaveBlue on @Instagram and @Twitter

If you would like to see images of animals like turtles, rays, whales and seals in their marine environment, please take a look at my Pinterest site: https://www.pinterest.com/saltywave


References

Great Barrier Reef Marine Park Authority www.gbrmpa.com.au

CSIRO www.csiro.au/~/media/OnA/Files/MarineDebris4ppFactsheet-PDF.pdf

CSIRO www.csiro.au/~/media/OnA/Files/MarineDebris4ppFactsheet-DOC.docx

Department of the Environment and Energy http://www.environment.gov.au/marine

The Conversation https://theconversation.com/marine-debris-biodiversity-impacts-and-potential-solutions-2131

The Conversation https://theconversation.com/ghostnets-fish-on-marine-rubbish-threatens-northern-australian-turtles-11585

Engadget http://www.engadget.com/2015/11/25/australia-shark-drones/

Discover Magazine http://blogs.discovermagazine.com/drone360/2015/06/16/video-drones-sharks/#.Vlv683jNCS0