Shark pups growing up to be vulnerable and weaker predators due to global climate change, finds study
Researchers say that the problem is grave but unfortunately, there is no straight forward solution
While the number of adult sharks is rapidly dwindling thanks to the ruthless fin trade and other human activities that operate without bounds, a recent study has found that its impact is slowly engulfing baby sharks too.
A new study has found that baby sharks lose physical strength and grow less.
The research studied a total of 546 young blacktip reef sharks, that were captured and measured during a four-year period between two locations: one in St Joseph Atoll in Seychelles and the other in Moorea, French Polynesia.
Their food habits and energy reserves were analyzed. The researchers first measured their body length and weight at birth and then a few weeks later measured their girth in order to get an idea on the sharks' body condition at birth and a few weeks later.
Then the frequency of the shark's stomachs that contained prey was analyzed.
The population of baby sharks occurring in Seychelles, an area that is small and uninhabited were found to be smaller and lighter in size but grew up to be more successful predators later in life than their Polynesian counterparts.
Juvenile blacktip reef sharks as a study species were chosen because this shark is known to use nearshore areas as nurseries for their young, said study author Ornella Weideli from the Save Our Seas Foundation D'Arros Research Centre and Ph.D. student at the Centre de Recherches Insulaires et Observatoire de l'Environnement (CRIOBE) in France.
"We found that sharks from Moorea, although larger and heavier at birth, started foraging for food later in life, which resulted in considerable declines in their body condition," she tells MEA WorldWide (MEAWW).
Moorea is inhabited and a popular tourist island. It is also bang-on in the center of the largest shark sanctuary in the world. The stressed environment was the cause, they believe.
For baby sharks, stressors can range from habitat development such as destroyed mangrove forests for new buildings and roads, etc, artisanal fisheries that catch sharks as bycatch as well as fisheries that deprive the sharks' prey resources, pollution and the mother of all environmental evil, scientifically proven — climate change.
"One of the big points to make with our studies in these locations is that even the most pristine locations, Seychelles and those centered in the largest shark sanctuary in the world are not immune to global climate change," says Dr. Jodie L. Rummer, co-author of the study from the ARC Centre of Excellence for Coral Reef Studies and a 2015 UNESCO-L’Oréal Women in Science Fellow.
"Climate change crosses all of those dotted lines that mark the boundaries of marine parks and sanctuaries," Dr. Rummer adds. Researchers say that the problem is grave but unfortunately, there is no straight forward solution.
However, several options do exist like creating temporal zones where no fishing is allowed during the pupping season so that they have access to preys as well, habitat development control in places where these populations exist, where the development is effectively sustainable or limited and fighting climate change to prevent the increase of water temperatures in shallow areas.
The hurdles when it comes to implementing these solutions are immense as well. With human settlements large in coastal areas, there is bound to be a clash with the local community with regard to restricted fishing zones and construction sites, says Weideli.
At the end of the day, the implementation lies in the hands of our Presidents and lawmakers. "To prevent our global temperatures from rising further, drastic changes and adaptations are needed to be undertaken by each one of us and by our politicians. However with an increasing human population, it is a very challenging hurdle," she said.
She also adds that education will play a central part, quoting Senegalese forestry engineer Baba Dioum, "In the end, we will conserve only what we love, we will love what we understand and we will understand only what we are taught"