MOVEMENT ECOLOGY OF APEX PREDATORY SHARKS By: Dr. Neil Hammerschlag

Why Study Movement?  Ecological & Evolutionary Processes are linked to movement  Understanding movement  management & Conservation strategies  Restoring degraded habitats  Preventing spread of invasive species  Protecting wildlife

Shark satellite tagging  Recent advances in satellite tagging and tracking are allowing scientists to “spy” into the secret lives of marine animals  We are currently using satellite tags to track the movements of shark species in the subtropical Atlantic  The goal of this work is to understand the migratory routes and residency patterns of these sharks to identify “hot spots” in place and time that are critical for mating, giving birth and feeding as well as locations where these animals are vulnerable to destructive fishing  By characterizing and identifying these hot spots, we can help supply policy makers with the data they need to implement effective management strategies that will improve conservation for these species.

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Possible Questions  What is the distribution of the 3 sharks? How do they differ?  Are their movements correlated with any environmental conditions (sea-surface temperature, chlorophyll content)?  What types of habitats do they use (e.g. reef, seagrass, open-ocean)? How would you characterize their eco- type (e.g. coastal, semi-costal, pelagic)?  Could there movements be related to diet?

Possible Questions  What jurisdictions do they inhabit or move through (e.g. Florida waters, international waters, marine protected areas)?  To what extent is shark habitat use divided among different marine protected and political-economic zones?  What areas are sharks most vulnerable to fishing?

Real time data  Excel database for satellite tagged sharks  Bull shark, tiger, hammerhead shark  Excel worksheet for each individual of each species  Size – Sex - Date – Latitude - Longitude

Resources  Online curriculum - school-curriculumhttp://rjd.miami.edu/education/high- school-curriculum  FL Natural History Museum – Education – Biological Profiles  Google Earth  NOAA Spatial registry  MPA Atlas -  NOAA Data tools tools/index.htmlhttp://cmsp.noaa.gov/data- tools/index.html  Global shipping lane

Bahamas

Mercury Toxicity  As apex marine predators, sharks are susceptible to mercury contamination through bioavailability and bioaccumulation of mercury via natural food web cycles. Mercury exists in the environment in many forms from natural elemental mercury (Hg) to toxic methyl mercury (MeHg). Some of this mercury is naturally occurring while some is derived as waste from anthropogenic sources such as power plants, incinerators, and industrial plants. Bacteria can convert total mercury into the toxic form of MeHg, which is then available to the food chain.  By examining mercury concentration in sharks, a top-down approach, we may learn about mercury contamination through the entire food web. We will also learn about contamination in certain species of shark, and what that means to the individual animal. Not only are sharks at risk to mercury contamination but humans consuming shark meat are also at risk to contamination, exhibited by standardized human health advisories and thresholds.  This may be useful when considering human health advisories, such as the Federal Drug Administration’s 1.0 μ g/g (ww) action level for human health concerns.

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Possible Questions  Which species is at most risk to mercury contamination?  How do mercury levels relate to human health thresholds?  What does mercury contamination mean to sharks?  Does size of shark and its mercury level relate to size of prey item?  Can mercury affect overall shark populations?  Can total length be used as an estimator of muscle mercury (per species)?  What is the source of mercury in southern Florida?  Do species that eat the same prey items accumulate similar levels of mercury in their muscle tissue?

Real time data  Excel database for Mercury in Sharks  Excel worksheet for 500 samples  Size – Species - Sex - Date – Latitude – Longitude – Mercury Concentration Hg & MeHg  Project description & meta-data

Resources  Online curriculum - school/MODULE%205%20Management,%20Conservat ion,%20Research%20and%20Actions%20- %20SECTION%203%20Mercury%20Toxicity%20Data. pdf school/MODULE%205%20Management,%20Conservat ion,%20Research%20and%20Actions%20- %20SECTION%203%20Mercury%20Toxicity%20Data. pdf  NIH — Mercury NIH — Mercury  EPA — Pollutants EPA — Pollutants  WHO — Mercury WHO — Mercury  MercuryPoison.com — Seafood Consumption MercuryPoison.com — Seafood Consumption

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