March 2014

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Are sharks apex predators? Does it matter?

We commonly refer to sharks as apex predators. Are they really? If they are not, does it matter? A few Australian researchers have come up with some answers to both questions.

First, are sharks apex predators? According to their findings, the answer is yes …. and no.

Example of an apex predator!

Here is what they found. “While size can be important in terrestrial ecosys- tems, size is crucial in marine ecosystems — which tend to be dominated by indeterminate organisms that grow continuously throughout their lives (Trebilco et al. 2013). Individual function changes due to onto- genetic diet shifts as organisms grow in size (Karpouzi

& Stergiou 2003, Pinnegar et al. 2003). The conse- quence is that size-structuring within communities, rather than species identity, is an important factor in determining the strength of competitive and predatory interactions (Dickie et al. 1987, Kerr & Dickie 2001). For example, studies have shown high overlap in diet between similar-sized sharks regardless of maturity state and species identity (e.g. Bethea et al. 2004). Therefore, designation of marine species into apex and mesopredator categories should consider the life stage and size of individuals.”
I’m not a scientist, but what I’m getting is, size matters!
But so, why should we care? We are not scientists, (well, you may be, but I’m not) so what does a classification matter? 
Here is what they have to say to that. 

Example of a meso predator!

“Our size-based view of the classification of predatory roles raises important questions about what objectives to manage, and how these objectives can be best achieved. Protection of reef communities through marine protected areas (MPAs) or fisheries regulation (or indeed, naturally on those few locations far from human population centres) would ensure the mesopredator sharks on these reefs are sheltered from fishing pressure. However, the same may not be true for apex predators because their broad movement patterns and large home ranges (Meyer et al. 2009) would expose them to a greater diversity of fishing fleets and gears, and thus a greater overall mortality than the smaller-ranging, reef-dwelling mesopredators. Hence, the apex pred- ators of coral reefs may be silently eliminated by offshore pelagic longline fisheries, unbeknownst to those managing reef diversity and function (Cox et al. 2002). Therefore, reef-based MPAs are not adequate to protect these species”

So basically they are saying that we need to do more than establish MPAs to adequately protect apex predators.

Here is a graphic that may be a bit more clear on the subject.
 

This graphic shows, that without MPAs prey species would greatly increase, while both mesopredators and apex predators decrease. With reef scale (small, local) MPAs, the mesopredators thrive, keeping the prey species in balance, but the apex predators still decline.

 

In practical terms, this means that we have to protect apex predators on a much larger scale than the less migratory mesopredators. In order to do that, we need to know both where they are and when they are there. With that knowledge we can push for local and/or seasonal protection for these migratory apex predators. In order to get that data, we need data that shows the migratory behavior of the various species of apex predators. 
You can read the entire paper here.

Cheers,
Martin Graf
CEO

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com

12
Mar 2014
By Shark DiverShark travel, swimming with sharks, UncategorizedComments Off on Are sharks apex predators? Does it matter?

Is Australias government coming to it’s senses?

http://www.speakupforblue.com/wordpress/wp-content/uploads/2014/01/WA-Shark-Cull.jpgGreg Hunt, Australia’s federal minister for the environment, has released a statement to the press, “The Federal Government will require the West Australian Government to undertake a full environmental assessment of Western Australia’s Shark Mitigation Strategy.”

Even though they can continue the current program until the end of April, the release  further states “However, as I have previously informed the West Australian Government on making the original decision, there would be no further extension without a full assessment.

Western Australia will need to refer the program for assessment under national environment law.  We will work co-operatively with the West Australian Government through this process.”

You can read the entire press release here.

This is a good first step. Let’s hope that when they review the policy they actually listen to the scientific evidence and not just the fear mongers in the West Australian government.

Cheers,
Martin Graf
CEO
Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.

11
Mar 2014
By Shark Diverenvironmental policy, swimming with sharks, Uncategorized, West AustraliaComments Off on Is Australias government coming to it’s senses?

Is shark diving a threat to conservation efforts?

Our friend Mike Neumann from Beqa Adventure Divers is featured in this article on shark diving and it’s impact on conservation efforts.

Mike Neumann lives in the tropical paradise of Fiji and scuba dives with large bull sharks all the time. In addition to having a dream job as a co-owner of a scubdiving company called Beqa Adventure Divers, Neumann likes exposing people to sharks so he can help improve the image of these misunderstood and threatened animals. “It is always inspiring to observe the awe and exhilaration, especially of the newbies once they realize that the sharks are nothing like the negative stereotypes,” he says, “but instead simply awesome and beautiful!” 

It’s not all fun and games though. Eco tourism goes beyond the operators trying to make a living.

Neumann’s opinion about the benefits of ecotourism for shark conservation is shared by many scuba-diving business owners in the growing shark ecotourism industry, with more than 375 unique shark diving businesses as of 2011 (pdf). Recent research (pdf) suggests that these scuba business owners might be right: public perception of sharks is important to their conservation. For instance, Christopher Neff, a PhD student at the University of Sydney who studies the policy implications of shark bites, says, “Laws often save or protect what the public cares about and can punish what it doesn’t. Perception matters a lot in terms of both laws and local responses to sharing beach ecosystems.” 

Unfortunately there has been a trend in the industry to do crazier and more extreme things. Some operators don’t care about the possible consequences their actions have, not only for themselves and their clients, but the rest of the industry and most important, the sharks.

Image link

A new trend in “shark riding” has shark conservationists anticipating an accident, which would likely result in negative media coverage of sharks and potential consequences to the industry. This risky behavior includes riding, prodding, grabbing, excessively handling and otherwise harassing sharks. Sharks are large, wild animals, and their behavior can be unpredictable. So, riding or harassing activity greatly increases the chance that someone will be injured. Such an injury could undo the progress made by ecotourism to public perception of sharks. “These close interactions with large predators are always dangerous,” Neumann says. “Highly experienced people may possibly limit those risks through adequate behavior and safety protocols, but the increasing number of inexperienced copycats makes me fear that somebody will end up having a bad accident.”  

Now, if someone does get hurt or worse, we all know what will happen in the media. The article of course states it a lot more eloquently.

Based on his analysis of how the media covers shark bites and a “if it bleeds, it leads” mentality, Neff thinks that if such an accident occurred, the incident would make headlines around the world. Nearly 20 percent of media-reported shark bites in Australia since 1979 resulted in no injury whatsoever to the human, yet the language used in news coverage often perpetuated the misconception of sharks as mindless killers. “The high degree of attention toward shark bites makes them seem more frequent than they are,” Neff says. “Someone in Poland is seeing coverage of a shark bite in Mexico and someone in Montana is hearing stories out of Florida, so even though these events are really rare they appear to be happening everywhere all the time—so our sense of probability is off. The result is often more negative responses.” Neff expressed concerns that media coverage of an accident resulting from risky diver behavior would likely be inflammatory. Such coverage could be damaging to the scuba industry by scaring potential customers away, and harmful to public perception of sharks by perpetuating false stereotypes of them as seeking out humans to eat.
 
So not only would the bad publicity from an accident hurt the sharks public image, but the actual act of handling the sharks could have an impact on them.

In addition to the possibility of an accident that would affect much more than the scuba diver who was bitten, there are other concerns about excessively touching, grabbing and riding sharks. The physiological stress associated with this behavior is unknown, and could be significant. Mike Neumann adds, “I hope that everybody agrees that riding harmless species like turtles, manatees, nurse sharks, manta rays or whale sharks is totally disrespectful and moronic, so why would riding those predatory sharks be anything else?”

So what should we do?

Safe and responsible shark ecotourism helps correct misconceptions of sharks for countless scuba divers. And a “look but don’t touch” policy can help further shark conservation by combatting the broader public’s misconceptions fueled by media coverage of shark bites and the 1975 blockbuster movie, Jaws. The growth of responsible shark-diving ecotourism (pdf) has led to a new talking point for conservation activists: that sharks can be more valuable to a local economy alive than dead. After research showed that a live shark can be worth 94 times as much via ecotourism than a dead shark can be worth through fishing (pdf), the Maldives banned shark fishing throughout their exclusive economic zone in the Indian Ocean.

The increase in dangerous and unnecessary thrill-seeking behavior with sharks makes SCUBA divers, conservationists and researchers worried that it’s only a matter of time before there’s a serious accident that could undo all of this progress.

We at Shark Diver couldn’t agree more with Mike’s concerns. Our motto is “Safe and Sane” shark diving. We have been operating our shark dives for 14 years, without handling, or riding sharks. Our goal is not to portray the sharks as harmless pets, but rather as the awesome predators they are. We teach our divers to respect, but not fear our toothy friends.
 
Cheers,
Martin Graf
CEO
Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.

04
Mar 2014
By Shark Diversafe and sane shark diving, shark handling, swimming with sharks, UncategorizedComments Off on Is shark diving a threat to conservation efforts?