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Divers counting sharks.
Because every shark counts!


Answers for frequently asked questions about SharksCount

Photo Credit: Jim Abernethy

 Do I have to be an experienced diver?

No. SharksCount is easy and not restricted to SCUBA divers. You can count sharks while you dive, snorkel or fish (preferably catch and release) whether you are a local or a visitor.

How do I sign up?

Email us at sharks Tell us where you dive most often and we'll add you to our growing team list of counters worldwide. We'll contact you and the entire team with data sheets, ID sheets, and more information regularly. Thank you for joining the program.

Can my dive club get involved?

Absolutely! Ask your dive club or dive shop to include SharksCount in their activitives and we can provide all survey materials and training upon request.  Contact us at for more information.

Is the shark-sighting data secure?

This is an important question because of the sensitive nature of the data – the quick and profitable harvest of a local shark population (legally or illegally) can be tempting to some and online data should never be a source for such temptations.  Always ask this question before submitting data about sharks or other harvested marine animals to anyone, especially online.

We protect your shark sighting data, especially locations of sightings, in three important ways:

1. When the data is mapped and visually shared on our webpage, the species and numbers of sightings are displayed by region, never by specific location. This is to safeguard the shark populations themselves and to respect any proprietary dive sites.

2. The SharksCount program applies 256-bit encryption on all data collected and stored.

3. We require all participants to register with Shark Savers and log in with unique IDs and passwords when submitting their data online.

The safety of the shark populations you dive with and value is of the highest importance to us. Please share any concerns or questions with us at

What is a "shifting baseline" and why is it important?

The term “shifting baseline” refers to the situation where we observe the natural world as it is now, often forgetting the former state of populations or habitats, and measure change against a ‘baseline’ condition that has often already changed or declined. It was first defined by fisheries biologist Daniel Pauly of the University of British Columbia in 1995. 

This is particularly important with regard to sharks because some local populations have declined by 90% or more over the past few decades.  Yet as new divers we may perceive that the current frequency that we see sharks is the ‘norm’ for the habitats we frequent.

For more information on this topic, please see the list of articles and papers below.

Additional Resources


S.K. Papworth, Rist J., CoadL., and Milner-Gulland E.J. 2009. Ecology and Organismal Biology. 2:2: 93

  • Shifting baseline syndrome (SBS) is often referred to as a key issue for conservation, yet there is little evidence for its existence. The presence of SBS could influence the validity of participatory monitoring, local ecological knowledge, community based conservation, and conservation education. We outline two forms of SBS: (1) generational amnesia, where knowledge extinction occurs because younger generations are not aware of past biological con2009ditions and (2) personal amnesia, where knowledge extinction occurs as individuals forget their own experience. Two conditions are essential to the identification of SBS: (1) biological change must be present in the system and (2) any perceived changes must be consistent with the biological data. If age or experience-related differences in perception are then found, generational amnesia may be occurring. Alternately, if individuals believe current conditions also occurred in the past, personal amnesia may be occurring. Previous studies have not fully addressed these conditions, and hence cannot provide indisputable evidence for the existence of SBS. We present three case studies to examine these issues, which demonstrate both forms of SBS. Shifting baseline syndrome is no longer a cautionary tale, but instead is a real problem for those using human perceptions of change to inform conservation policy-making or management.

Jeremy B.C. Jackson and Nancy Knowlton. 2008. Shifting baselines, local impacts, and global change on coral reefs. PLoS Biology. 6.2: 215.

  • This paper gives a broad overview of shifting baselines on coral reefs. Areas adjacent to coral reefs with high human populations typically impose more human-induced stressors on reef communities. These stressors, like overfishing and pollution, make it harder for coral reefs and associated species to withstand negative physical or biological factors, like changes in temperature, salinity, predators, or invasive species. Apex predators are of the biggest concern, since they are being overfished in many reef habitats and surrounding areas.

  • Where have all our sharks gone? A historic shark fishery in Salerno, Florida gives insight into past abundance of sharks and the drastic declines that we are seeing today. To supply the growing demand for shark liver oil, sharks’ teeth, and “shark meal,” the Port Salerno Shark Factory “employed as many as 50 people and used 12 boats to haul in the 'tigers of the sea' some 25,000 or more per year.” Now these sharks are rare, suggesting that even local fishing by one small fishing village has the capacity to decimate an entire shark population in a matter of decades.

S. A. Sandin et al., Baselines and Degradation of Coral Reefs in the Northern Line Islands. PLoS ONE 3, e1548 (2008).

  • Establishing baselines of ocean health are important in determining effective management. Looking at adjacent reefs in the Northern Line Islands, Sandin and colleagues found that sharks were virtually absent on the more populated islands, while the majority of top predator biomass were sharks on the more pristine islands with no humans. The authors concluded that protected reefs with a higher biomass of top predators, like sharks, are more resilient to disturbances like coral bleaching that result from global warming.

M.R. Heithaus, Burkholder, D., Hueter, R.E., Heithaus, L.I., Pratt, Jr., H.L., and Carrier, J.C. 2007.  Spatial and temporal variation in shark communities of the lower Florida Keys and evidence for historical population declines. Canadian Journal of Fisheries and Aquatic Sciences, 64: 1302-1313.

  • Historic accounts of a shark fishery in the Florida Keys suggest the depletion of shark populations at Heithaus and colleagues’ study site. This lead them to conclude “ecosystem impacts of changes in the large shark community may be dramatic and likely occurred before adequate baselines were established.”

Baum, J.K. & Myers, R.A. (2004). Shifting baselines and the decline of pelagic sharks in the Gulf of Mexico. Ecol. Lett., 7, 135–145.

  • Baum and Myers compare historic and recent catch rate data to estimate regional shark declines in the Gulf of Mexico. Due to their vulnerable life history characteristics, sharks are extremely vulnerable to any exploitation. Baum and Myers state their “analysis provides the missing baseline for pelagic sharks in the Gulf of Mexico that is needed for the rational management and restoration of these species.”

Ecological extinction and evolution in the brave new ocean. Jeremy B. C. Jackson

  • Jackson provides an overview of the global patterns of marine species exploitation. He illustrates the problems facing each major ocean realm and lists the percent decline for plant and animal species from various marine ecosystems. Jackson and colleagues have shown that many coastal and pelagic shark species have shown dramatic declines, some reduced up to 99% in particular regions.

Cascading Effects of the Loss of Apex Predatory Sharks from a Coastal Ocean. Ransom A. Myers, Julia K. Baum, Travis D. Shepherd, Sean P. Powers, Charles H. Peterson. 2007. VOL 315. SCIENCE.

  • Drastic declines in top predatory sharks have had cascading effects, leading to the decline of a 100-year-old scallop fishery in the northwest Atlantic.

How severe are shark population decreases, and how do we know? By WhySharksMatter, on April 19th, 2012

  • It is impossible to know exactly how many sharks there are in the ocean; however, there are several ways to estimate population trends of sharks. This is a review of those methods and supporting literature

An open letter concerning the unsustainability of shark finning. White Shark Conservation Trust. 29. May 2012

  • The shark fin trade is not sustainable. There is an abundance of scientific evidence that many shark populations are in decline, and a lack of adequate management and protection for these species. International shark experts call for urgent attention and action, in order to curb these declines and strengthen marine ecosystem integrity.

Shifting Baselines - How Can We Protect The Future Of The Oceans If We Don’t Know The Past? Randy Olson, 2006

  • ‘Shifting baselines’ is a term coined in 1995 that refers to the fact that “we assume that the way we see the world is the way it’s always been.” Unfortunately, we do not know historic state of our world and resources, so we do not know what we are missing. However, scientific studies that compare nearby atolls with varying levels of human disturbance give insight into the way the world used to be.

What is “zero-data” and why is it important?

 “Zero-data” is documenting the absence of something – in this case, sharks. And this data is vital for the SharksCount program to have maximum applications to conservation.  If you go on a dive and see no sharks, please record that dive on your datasheet and report it to us. All your diving information is valuable.

This is important to remember because when divers record the species they encounter on a dive, this only documents the presence of the species of interest. However it is equally important to record the absence of certain species, like sharks. Today, sharks are largely absent in areas where they were once abundant. Providing data that illustrates where sharks are present and absent helps scientists establish baselines of shark populations.

Scientists use presence/absence data to understand the roles that human disturbance plays in the distribution/abundance of coastal shark populations. Overall, larger shark species are often depleted or absent in areas with high levels of fishing and human disturbance.

The information you submit to the SharksCount Program can help scientists and managers prevent further loss of sharks by designating priority conservation areas, measuring the success of management strategies for protecting sharks, informing communities about the overall presence/seasonality of sharks in their area and dive sites, and understanding population changes through time.

For more information, please review the resources below.

Additional Resources

Stallings C (2009) Fishery-independent data reveal negative effect of human population density on Caribbean predatory fish communities. Plos One 4: e5333.|utmccn=%28organic%29|utmcmd=organic|utmctr=%28not%20provided%29&__utmv=-&__utmk=237423427


C. A. M. Ward-Paige, C.; Lotze, H. K.; Pattengill-Semmens, C.;, L. A.-C. McClenachan, E.; Myers, R. A. , Large-Scale Absence of Sharks on Reefs in the Greater- Caribbean: A Footprint of Human Pressures. PLoS ONE 5,  (2010).


C. A. a. L. Ward-Paige, Heike K. , Assessing the Value of Recreational Divers for Censusing Elasmobranchs. PLoS ONE 6,  (2011).