A recently published study on global shark catch and mortality rates by researchers at Dalhousie University in Halifax, Canada has been popping up in the mainstream news media. Many news agencies are reporting that the gist of the study is that “100 million sharks are killed every year.”

However, the report goes on to say that number of sharks killed annually could fall into the range of 63 million to 273 million. The study also estimates that between 6.4% and 7.9% of the global shark population are killed each year. This range exceeds an estimated rebound rate of 4.9% for many species of sharks, based on life history data of 62 different species of sharks. If these estimates are correct and the mortality rate exceeds the rebound rate for a particular species, a population decline in that particular species would be inevitable.

For more information, check out the full journal article, “Global catches, exploitation rates, and rebuilding options for sharks” by Worm et al.

According to the OCEARCH Facebook page, the OCEARCH team has successfully tagged a 14.5′ female white shark (Carcharodon carcharias) off the coast of Jacksonville, FL. The shark, nicknamed “Lydia,” is the first white shark ever to be SPOT tagged off the Florida coast.

Tracking data from tagged great white sharks has been surprising some researchers.

The travels of great white sharks (Carcharodon carcharias) equipped with the SPOT tags in both the Atlantic and Pacific Ocean have surprised researchers over the past month or so.

According to OCEARCH’s Global Shark Tracker, an adult female white shark (nicknamed “Mary Lee”) left Cape Cod waters last September and headed south, as researchers had expected. By the beginning January, Mary Lee had made her way to the waters off northern Florida, which was inline with the theory that Atlantic white sharks spend their time in waters off the southern states of the east coast of the United States during the winter months and then head north during the summer months when water temperatures rise.
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The Humane Society of the United States is reporting that Texas lawmakers have introduced legislation that would make it illegal to sell, purchase or transport shark fins in the state. The bill (HB 852/SB 572) was introduced by Representative Eddie Lucio III, and Senator Larry Taylor. If passed, the law would take effect on July 1, 2014. Similar legislation has been passed in California, Hawaii, Illinois, Oregon, and Washington.

You can read the full text of the proposed House and Senate bills by following the links below.

83(R) House Bill 852
83(R) Senate Bill 572

Should beachgoers be worried about year-to-year changes in shark attack numbers?

The University of Florida’s International Shark Attack File released its 2012 findings this past Monday, and some major media outlets were quick to report that the 53 “unprovoked” shark attacks in the U.S. last year ties the “record number” of annual attacks reported in the U.S. (the same number of attacks was reported in 2000). While the data seems pretty straight-forward, what does a record number of shark attacks actually mean from a scientific and statistical standpoint?

As the ISAF 2012 summary is quick to point out, short-term trends should be viewed with caution as they are not necessarily indicative of any kind of statistical significance. When viewing annual counts of attacks, each annual number of attacks is a single data point making the possibility of any one year’s count being an outlier, and the ISAF summary notes that year-to-year variability is high.

The report goes on to state that the number of “unprovoked attacks” worldwide has consistently increased each decade since 1900, and while no statistical analysis of this data is discussed in the summary, it seems that a significant positive trend in the number of reported attacks exists. But, does an increase in the number of reported attacks translate to an increased risk of being attacked by a shark? Are individual beachgoers across the U.S. (and the world) less safe from shark attacks now than they were in the past? To answer these kinds of questions, one must consider more data than simply the number of reported attacks.

The 2012 summary discusses other factors which can affect the number of reported attacks. The report states that the number of shark-human interactions is directly correlated with the number of hours humans spend in waters where sharks are found. The report goes on to say that an increase in attacks should be expected over time as an “upsurge” in aquatic recreational activities continues. In addition to more people being in the water, the ISAF also has improved its efficiency in recording attacks over the past few decades, which logically would result in an increase in reported attacks, even if the number of actual attacks remained consistent during this time period, given the assumption that not all attacks were recorded.

The gist of this past year’s ISAF summary seems to be that while the data might indicate a “record number” of attacks in the U.S. and a slight increase in worldwide attacks from 2011 to 2012, the relative risk of an individual human being involved in a shark attack has not necessarily increased over the past year.

California white sharks have endangered species protection during a one-year review period.

KABC-TV reports that the California Fish and Game Commission has voted unanimously to advance the candidacy of the great white shark (Carcharodon carcharias) as a potential endangered species. The status review will last for one year and will grant the species the same protections as a listed endangered species during the review period.

It is already illegal to target and harvest white sharks in California. The candidacy status will also make incidental catch of the species illegal in state waters.

The commission vote followed a petition from Oceana to protect the subspecies of white sharks along the California coast. According to the KABC-TV report, state researchers hope to get a more accurate estimate of population numbers during the review and will assess threats to the species. The commission will use the information gathered from the review to make an “informed decision” on whether to list the species as endangered under California law.

The great white shark is currently listed as “vulnerable” globally on the IUCN Red List.