Your Marine Sanitation Experts Share Important Reminders About How to Avoid Overfishing
Raritan Engineering your marine sanitation specialists would like to share with you these topics we thought would be of interest to you this month regarding the dangers of overfishing the shortfin mako shark.
Your marine sanitation distributors give ideas regarding a new study reports that the mortality rate of shortfin mako sharks due to fishing in the western North Atlantic is higher than previously estimated from catch reports.
The report, published online at phys.org and done using satellite tracking by researchers from Nova Southeastern University’s Guy Harvey Research Institute (GHRI), the University of Rhode Island and more, suggests the species is experiencing overfishing.
The study shows 30 percent of the 40 satellite-tagged sharks were captured. After modelling the probability that a mako shark would survive a year without being captured — a 72 percent chance — and calculating the fishing mortality rates, researchers determined that the rate at which shortfin makos were being killed in fisheries was actually 10 times higher than previously believed.
The tracks of the tagged mako sharks, including the ones captured, can be viewed online on NSU’s GHRI shark tracking website.
The study used near-real-time tracking of mako sharks from satellite tags. Directly seeing how they were captured bypasses the dependency on anglers self-reporting the catches and details.
In the past, fishing was more sustainable because fishermen could not access every location and because they had a limited capacity for fish aboard their vessels. Today, however, small trawlers and fishing boats have been replaced by giant factory ships that can capture and process extremely large amounts of prey at a given time (2). These ships use sonar instruments and global positioning systems (GPS) to rapidly locate large schools of fish (1).
Your Marine Sanitation Professionals Talk About Safe Fishing Options That Don’t Risk Endangering a Species
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Fishing gear is often non-selective in the fish it targets. For example, any fish that are too big to get through the mesh of a net are captured. Therefore, overfishing does not only threaten the species of fish that is targeted for food, but also many non-target species. As a result, these other species, including marine mammals and seabirds, are accidentally caught in the fishing gear and killed (6). For example, for every ton of prawn caught, three tons of other fish are killed and thrown away.
Today, the number of fish caught worldwide is actually shrinking as the fishing industry is in decline from many years of overfishing (2). The year 1988 was the first time in human history that global wild fish catches dropped and they have continued to fall ever since.
As previously mentioned, shark populations have also been greatly affected by overfishing. There are already more than 135 species of shark on the IUCN’s list of endangered animals and more are being added each year. For example, the number of scalloped hammerhead shark has decreased by 99% over the past 30 years.
A recent study found that overfishing is also decreasing the genetic diversity of fish worldwide. Diversity is projected to be reduced further if overfishing continues at the same rate (13). This has serious effects on nutrient recycling in marine ecosystems because fish species vary widely in their rates of nitrogen and phosphorus excretion.
Given that fishing is a food source for millions of people, attempting to solve the problem of overfishing not easy, especially for developing countries.
Australia to Expand Commercial Fishing in Marine Sanctuaries
Draft guidelines released on Friday propose increasing the total proportion of Australia’s marine reserves permitting commercial fishing from 64 to 80 per cent. If environment minister Josh Frydenberg’s proposal is approved, Australia will become the first country to wind back its ocean protection measures.
At the moment, 36 percent of Australian waters are classified as marine parks. These areas are closed to oil and gas exploration and restrict commercial fishing to defined zones where the environmental threat is considered low.
Under the proposed changes, one of the hardest-hit regions will be the Coral Sea marine park adjoining the Great Barrier Reef near Queensland.
Industry vs the environment
Frydenberg is proposing cutting the no-fishing areas of the reserve by 53 per cent to “enable a continued Australian tuna fishing industry based out of northern Queensland”.
The type of tuna fishing that will be allowed – known as pelagic longline fishing – could harm other marine species, says Darren Kindleysides at the Australian Marine Conservation Society.
The draft plan to expand commercial fishing is now open to public consultation and could be implemented as early as 2018. The government has also flagged that it is considering additional future cuts to marine park protections, including introducing “blue zones” to permit underwater oil and gas mining.
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