How Can I Help ? Three easy steps you can take every day to help the ocean

By Julie Vecchio, USF, Ph.D. candidate

If you love the ocean, you know it is in danger. There are many threats to the organisms and ecosystems within the ocean, but what can YOU, just one person, do about it? Here are a few suggestions that you can follow every day that can reduce your impact on the oceans.


Clothing, shoes, toys, and electronics are all good candidates for buying gently used. In the United States alone, 16.2 million tons of textile waste is generated every year. Less than a quarter of this waste is recycled. Buying used clothing and toys from a thrift store or consignment shop not only saves the materials, water, and electricity to produce the new product, it also saves a large amount of waste from going into landfills (1).

My take on it: I have a toddler who outgrows his clothes and toys about every 6 months! By buying his clothes and toys from a consignment shop, I am not only saving at least 50% on all the “stuff” I buy for him, but I’m also saving those items from being trashed by someone else.



According to USGS each person in the U.S. uses between 100 and 180 gallons of water per day (2). All of this water goes into the municipal sewage stream (if you live in a city). This water is usually funneled toward wastewater treatment plants located on the edge of the nearest body of water then cleaned using several steps. About 90% of the chemicals and nutrients in the water are removed by this process (3), but 10% remains and is released into the environment, eventually making its way to the ocean. These chemicals can have a variety of effects on ocean ecosystems from anoxic zones to hormone disruption (4, 5).

You can reduce your water consumption by a few simple measures. First, turn the tap off while brushing your teeth, or washing your face and hands. Second, follow the “if it’s yellow, let it mellow” rule. Third, take shorter showers or don’t shower as often. Wash your hair less often. If you have an automatic sprinkler system, install a rain gauge to shut down the sprinklers when it has rained. Cities will often do this for you for free. All of these steps will help reduce freshwater consumption, but also reduce the amount of excess nutrients and chemicals that make their way to the ocean.

My take on it: I have spent several years of my life living on sailing or motorized vessels at sea. While many modern ships have desalinization plants to create fresh water, many of the vessels I have lived on did not. Whatever water we brought from the dock was the water we had, for drinking, bathing, cooking, etc. This experience has trained me to think twice before turning on the tap or leaving it running. For instance, I only wash my hair about once a month but I rinse it every time I get in the shower. We only run our sprinkler system when the grass is looking really brown, and I cringe each time it goes on.



By now, the amount of trash (specifically plastics) that end up in the ocean is a problem that is well known to most people. Over 300 million tons of plastic waste was generated in 2015 globally (6). Most of this was single-use plastics or plastic packaging. Many restaurants are starting to ask patrons if they need a straw instead of dropping them off automatically. This is a great step. You can encourage restaurants to do this by asking for “no straw” or even talking to management about making this simple change in their procedures.  Some states and municipalities are even outlawing plastic bags all together (7).


Photo from Shutterstock

My take on it: There are a few quick things I do (or try to do) to reduce my reliance on single-use plastics. First, I (almost) always use my travel mug. I brew my coffee at home in a French press and compost the grounds. If I’m out and I didn’t bring my travel mug with me, I think really hard about whether I need that cup of coffee. Most of the time I decide it’s not worth the trash. Second, I (almost) always bring my reusable bags to the grocery story. This saves somewhere between 7 and 9 plastic bags every week. Third, I pack my lunch every day for work. My lunch bag has a spoon and fork that live inside, I always eat leftovers from dinner the night before that I put in a reusable container, and I have reusable snack packs for my carrots and chips that I throw in the laundry. One thing I want to start doing is bringing my own doggie bag to restaurants. I go to certain restaurants where I know I will want to take some of my meal home with me. I am trying to remember to bring my own container so that I don’t take home a container that I’m just going to put in the trash.

Our best bet for a healthy ocean in the future is for each person to be mindful about their consumption, doing what they can when they can (8). If we all do our part, we can slow the environmental degradation that is threatening not only the ocean, but our livelihoods as well.






Exploring Fisheries Aspects of Large-Scale Habitat Restoration in Tampa Bay

By Kailee Schulz, UF Master’s Student



Estuaries form a link between marine and freshwater environments, harboring a rich assemblage of fish and plant species (Attrill and Rundle 2002). Because human population growth is typically highest near the coast and coastal freshwater environments, the loss and degradation of estuarine habitat is a major threat to resident species (Fitzhugh and Richter 2004, Vitousek et al. 1997, Kennish 1991). This is especially true for Tampa Bay, where a growing population of over two million reside within the ~5,700 km2 watershed (Greening et al. 2014, Rayer and Wang 2015). Habitat loss and degradation has led to an interest in large-scale restoration (Yates et al. 2011, Russell and Greening 2015). While improving environmental conditions through reductions in nutrient inputs are well documented, the benefits of restored, reconnected, and created habitats are still poorly understood, despite large initial investments in restoration efforts (Russell and Greening 2015).

The overall goal of my research is to understand how fish communities are utilizing restored habitats. Specifically, are restored sites functioning as suitable juvenile sportfish nurseries? I have two aims within these objectives: (1) describe the relationship between fish communities and habitat at three site types and (2) compare juvenile common snook (Centropomus undecimalis) growth and condition among habitats and sites.


Figure 2. The three restored (Cockroach Bay- restored, Rock Ponds, Terra Ceia), three impacted (Dug Creek, Newman Branch, E.G. Simmons), and three natural sites (Little Manatee, Cockroach Bay-natural, and Frog Creek) located within the Tampa Bay watershed.

To accomplish this, I sampled three impacted, three restored, and three natural sites quarterly (Fig. 2). An impacted site is a historically dredged canal or ditch that received minimal subsequent modification. A restored site is an area that has been physically and biologically modified to restore or create landscape characteristics that support aquatic communities. A natural site is an area with minimal physical and biological alteration to aquatic habitat. Beginning in March 2018, fishes were sampled quarterly at all 9 sites. 9.1 m and 40 m nylon seines were used for up to 9 and 3 samples per site, respectively (Fig. 3 and 4).


Figure 3. The 9.1 meter net being pulled into the shoreline at Terra Ceia Restoration.


Figure 4. The 40-meter net fully deployed and being pulled into the shore at Cockroach Bay natural site.

Collected fishes were identified to the species level using methods developed by Kells and Carpenter (2011). All sportfish, fishes of economic importance, and non-native species were counted, measured, and released. A subsample of common snook were retained for later analysis, with a maximum of 45 common snook per site kept during each quarter. These common snook were weighed and measured (SL, FL, and TL). The sagittal otoliths were removed and processed following protocols developed by VanderKooy (2009) (Fig 5). Juvenile snook age was estimated by counting daily growth rings along the sulcus beginning at the core. Two independent readers estimated age for each otolith, with the mean value used for analysis if both estimates were within 10%. Further, total lipid analysis was completed on the retained snook using the standard Folch extraction methods (Folch et al 1956). The age and of these juvenile snook will provide information on the functionality of the three site types. I also collected a variety of habitat parameters based on previous research by FWC’s Fisheries Independent Monitoring program (Table 1) and water quality which, when paired with the juvenile common snook condition, offer insight on the specific environmental conditions that provide functional juvenile sportfish nurseries.


Figure 5. The ventral side of a juvenile common snook with its two otoliths exposed, the opaque, oval bones sitting within the brain cavity.


Table 1. Habitat characteristics that are recorded at each seine pull. Unit of measurements with two variables include a species and the amount of space it covered the seined area. Recorded levels refers to the maximum number of parameter types that can be examined.

Thus far, I have caught 49,108 fish, a majority of which were collected at restored sites (Fig. 6). I found a significant difference in the growth rate between the snook caught at the three site types; restored, impacted, and natural. (Fig 7.) These preliminary data show that juvenile common snook grow faster at restored sites and natural sites compared to those at impacted sites. The next step is to evaluate snook body condition at the three site types. I will use the habitat characteristics and growth and condition of the juvenile snook to understand which specific habitat parameters are key in promoting successful nursery environments. The community structure will be evaluated at each site to assess which features promote a functional nursery habitat.


Figure 6. The number of animals (fish, shrimp, and crab species) caught at three site types. This is standardized by the number of individuals caught per seined m2


Figure 7. A comparison of juvenile common snook growth between three site types. There was a significant difference in mean growth rate between the three sites (F2,45 = 4.22, p = 0.021). Error bars represent SEM. Letters denote differences among site type as identified as TukeyHSD.

Habitat restoration is often conducted to benefit sportfish with many restorations aimed at improving nursery habitat (Lewis III 1992; Peters et al. 1998). This research will provide information on the parameters necessary in promoting juvenile sportfish success. Another goal for Tampa Bay restoration is enhancement of local diversity by creating and managing for habitat mosaics. To this end, I will compare fish community structure at sites with varying levels of habitat diversity. This research will be useful in future restoration projects and increase understanding of qualities that are important when designing and creating restoration projects. Habitat restoration is increasingly implemented as the human population continues to grow within the Tampa Bay watershed. Ultimately, my work will improve the effectiveness and utility of habitat restoration as it relates to fisheries resources.



Attrill MJ, Rundle SD (2002) Ecotone or ecocline: ecological boundaries in estuaries. Estuarine, Coastal and Shelf Science 55:929–936

Fitzhugh TW, Richter BD (2004) Quenching urban thirst: growing cities and their impacts on freshwater ecosystems. Bioscience 54:741–754

Folch, J. M. Less, and G.H. Sloane Stanley. 1956. A simple method for the isolation and purification of total lipids from animal tissues. Boston: Harvard University Press

Greening H, Janicki A, Sherwood ET, Pribble R, Johansson J (2014) Ecosystem responses to long-term nutrient management in an urban estuary: Tampa Bay, Florida, USA. Estuarine, Coastal and Shelf Science151:A1–A16

Kells V, Carpenter K (2011) A field guide to coastal fishes: from Maine to Texas. JHU Press, Baltimore, MD

Kennish MJ (1991) Ecology of estuaries: anthropogenic effects. CRC Press, Boca Raton, FL

Lewis RR III (1992) Coastal habitat restoration as a fishery management tool. Pages 169–173. In: Stroud RH (ed) Stemming the tide of coastal fish habitat loss. National Coalition for Marine Conservation Inc., Savannah, GA

Peters KM, Matheson RE Jr, Taylor RG (1998) Reproduction and early life history of common snook, Centropomus undecimalis (Bloch), in Florida Bulletin of Marine Science 62:509–529

Rayer S, Wang Y (2015) Pages 1–8. Projections of Florida population by county, 2015-2040, with estimates for 2014. University of Florida Bureau of Economic and Business Research Bulletin 171, Gainesville, FL

Russell M, Greening H (2015) Estimating benefits in a recovering estuary: Tampa Bay, Florida. Estuaries and Coasts 38:9–18

VanderKooy, S. 2009. A practical handbook for determining the ages of Gulf of Mexico fishes. Gulf States Marine Fisheries Commission Publication 167

Vitousek PM, Mooney HA, Lubchenco J, Melillo JM (1997) Human domination of Earth’s ecosystems. Science 277:494–499

Yates KK, Greening H, Morrison G (2011) Integrating science and resource management in Tampa Bay, Florida. Circular No. 1348. U.S. Geological Survey, Reston, VA

Coastal shark community assemblages

by Clark Morgan, University of North Florida, Master’s student

As animals grow and mature, their needs change. Throughout their life cycle, many animals relocate into different habitats to enhance their own survival, a process known as ontogenetic habitat shifts. Many shark species aggregate by size and life stage.  Smaller, younger sharks are found in “nursery” areas that have a high abundance of food resources and offer protection from predators (e.g. larger sharks). When a shark reaches sexual maturity, it often moves to another location where other like-minded (and bodied) sharks of the same species aggregate. These movements often correspond with changes in resource requirements for larger individuals. Multiple species often share resources, geographic areas, and prefer many of the same environmental conditions that deem a habitat suitable for use and consequently, complex communities are formed. Researching how these communities change in time and space can be a daunting task, but through the use of multiple methodologies, dynamic ecological questions can be answered for many scientific applications. Thus, understanding the relationship between sharks and their environment is crucial for sustainable management and conservation of shark populations (Simpfendorfer and Heupel, 2012).

Many coastal shark species of the southeastern United States are Carcharhinids, a family of fish known as the “requiem sharks.” A characteristic feature of this group is placental viviparity, in which pregnant females provide nutrients to their pups in uterovia placental connections before live birth. As a result, newborn pups have openings in their ventral surface that are essentially equivalent to a belly button in humans. These open umbilical scars heal quickly, but the size of the remaining wound can provide birthday estimations for these animals. Once completely closed, the presence of a healed umbilical scar is still useful for identifying an animal as a young-of-year (YOY), an important life-stage distinction.


A partially healed umbilical opening on a neonatal sandbar shark (Carcharinus plumbeus)

A shark’s length is the most useful way to determine its life stage, a result of many lethal studies that measured the development of internal reproductive organs at different sizes. Male elasmobranchs possess external reproductive organs known as claspers that are used in the internal fertilization of a female. These structures harden via calcification as an individual matures, which allows for a quick and easy assessment of life stage by a researcher. Quantifying species-specific life stage abundances and the corresponding environmental parameters of their habitats provides the framework for understanding ecosystems. This is becoming increasingly important for coastal ecosystems as the negative results of anthropogenic disturbances such as pollution, increased human populations, and coastal development can result in habitat degradation (Pan et al. 2013).


A mature male blacknose shark (Carcharhinus acronotus), with visibly large and developed claspers

Another useful method for assessing community interactions is known as Stable Isotope Analysis (SIA), which measures the naturally occurring ratios of heavy and light chemical elements found in animal tissue. Carbon (δ13C) and nitrogen (δ15N)are the most common isotopes measured. δ13C values trace the original base source of dietary carbon of a consumer, while δ15N values are indicative of relative trophic position (Peterson and Fry 1987, Post 2002).These ratios allow researchers to infer trophic levels, niche widths, and temporal foraging patterns, which provide deeper insight into how these communities may be competing for resources.To insure successful application of SIA, one must also consider the varying turnover time of different tissue types. Tissues that are less active in metabolic processing, such as muscle tissue, take longer for a change in diet to be reflected in a consumer’s isotopic signature (~1 year) while blood plasma provides dietary insight on a much shorter time scale (~2-3 months) (MacNeil et al. 2006; Matich et al. 2011). Comparing δ15N values of different tissue types from the same animal reveals temporal dietary changes which are common with ontogeny, while δ13C values indicate spatial dietary changes indicative of movements into areas of different carbon sources.

A combination of ecological factors like environmental characteristics, resource abundance and distribution, and the presence of other competing species influences nearshore habitat use by sharks (Knip et al. 2010).  Considering the known ecological importance of sharks, identifying influential factors on coastal shark habitat use is imperative to understand how shark species will respond to future changes in the environment (Heithaus et al. 2008, Pan et al. 2013, Yates et al. 2015).


Matich, P., Heithaus, M.R. & Layman, C.A. 2011. Contrasting Patterns Of Individual Specialization And Trophic Coupling In Two Marine Apex Predators. Journal Of Animal Ecology, 80, 295–304.

Post, D. M. 2002. Using Stable Isotopes To Estimate Trophic Position: Models, Methods, And Assumptions. Ecology 83:703–718.

Peterson, B. J., And B. Fry. 1987. Stable Isotopes In Ecosystem Studies. Annual Reviews In Ecological Systems 18:293–320.

Macneil, M. A., G. B. Skomal, And A. T. Fisk. 2006. Stable Isotopes From Multiple Tissues Reveal Diet Switching In Sharks. Marine Ecology Progress Series 302:199–206.

Heithaus, M.R., Frid, A., Wirsing A.J., Worm, B. 2008. Predicting ecological consequences of marine top predator declines. Trends in Ecology and Evolution 23: 202-210.

Knip, D. M., Heupel, M. R., and Simpfendorfer, C. A. (2010). Sharks in nearshore environments: models, importance, and consequences. Marine Ecology Progress Series 402, 1–11.

Pan, J., Marcoval M.A., Bazzini, S.M, Vallina, M.V., De Marco, S.G. 2013. Coastal Marine Biodiversity Challenges and Threats. Marine Ecologist in a Changing World. 43-67.

Yates, P. M., Heupel, M. R., Tobin, A. J., and Simpfendorfer, C. A. 2015. Ecological drivers of shark distributions along a tropical coastline. PLoSOne 10(4), e0121346.

Simpfendorfer, Colin A., and Heupel, Michelle R. (2012) Assessing habitat use and movement. In: Carrier, Jeffrey C., Musick, John A., and Heithaus, Michael R., (eds.) Biology of Sharks and Their Relatives. CRC Marine Biology Series. CRC Press, London, UK, pp. 579-601.

An assessment of Largemouth Bass fin rays and spines for use in non-lethal aging in Florida

By Summer Lindelien, MS student, University of Florida

Largemouth Bass (LMB) are a highly sought-after sport fish in the state of Florida. Many anglers fish for them recreationally, whereas others study them extensively. I happen to be both a trophy bass angler and a researcher. My love for fishing brought me into this field of study. I have always believed in conserving our bass fisheries for future generations, and when I saw the opportunity to attempt a methodology that has not been applied as frequently to warm-water fishes, I was eager and intrigued. Non-lethal aging of LMB in Florida has not been fully assessed, and it would benefit fisheries scientists and the public to know more about bass population structure (growth, mortality, and recruitment; Strickland and Middaugh 2015), especially when it can be difficult to find and capture a large number of trophy bass during field sampling, and killing fish is not an ideal option.


Figure 1. A) Clipping a Largemouth Bass anal fin, B) dorsal fin rays thawing prior to being excised, and C) seven fin structures (pectoral rays 3-5, anal spine III, anal rays 3-5, pelvic spine I, pelvic rays 2-4, dorsal spines III-V, and dorsal rays 3-5) properly excised.

For my study, LMB (N= 686) were captured using daytime boat electrofishing on Rodman Reservoir. Sagitta otoliths as well as dorsal, pelvic, and anal fin spines, and pelvic, pectoral, anal, and dorsal fin rays were taken from individual fish (Figure 1). The bony structures were cleaned and stored for later processing. Otoliths were mounted to slides and sectioned with a low speed saw to 0.5 mm in width, and fin structures were mounted in two-part epoxy then differentially sectioned from 0.7 mm to 1.4 mm. These sections were permanently mounted to slides and aged under dissecting or compound microscopes (Figure 2).


Figure 2. A) Largemouth Bass dorsal rays 3-5 excised and cleaned, prepped for the drying box, B) dorsal spines III-V imbedded in two-part epoxy, C) sectioning a fin structure with the low speed saw, and D) cross-sections (~0.7-1.4 mm) of several fin structures permanently mounted to slides.

Aging the otolith sections (Figure 3) was relatively simple compared to learning how to age each fin structure since fins all grow differently. After aging over 1,000 sections (Figure 4), I was able to identify which fin structure provided the most accurate (between otolith-based ages and fin structure-based ages) and precise (within-reader and between-reader ages) aging estimates by calculating the average percent error (APE; Beamish and Fournier 1981), coefficient of variation (CV; Chang 1982), percent agreement (PA; Sikstrom 1983), and Lin’s concordance correlation coefficient (ρc; Lin 1989; Lin et al. 2002; Lin et al. 2007). I used age biplots (Campana 2001; Figure 5), residual plots, and radii measurements (Murie et al. 2009; Figure 6) to understand age differences and potential reader biases. The dorsal fin spine (n = 122) provided the most precise (PA = 79%; CV = 4.0; ρc= 0.97) and accurate (PA = 77%; CV = 6.5; ρc= 0.98) ages relative to the other fin structures, and therefore was identified as the best potentially non-lethal aging structure.


Figure 3. A) A 0.5 mm sagitta otolith section from a 10-yr old Largemouth Bass (LMB), B) a sagitta otolith section from an 11-yr old LMB, and C) an otolith section from a 12-yr old LMB.


Figure 4. A) Dorsal spine section from a 9-yr old Largemouth Bass (LMB), white dots represent enumerated translucent bands, B) anal fin ray section from an age 4 LMB, white arrow represents the end of the first annulus which is a double band, and C) dorsal fin ray section from an age 4 LMB.


Figure 5. Scatter plot comparison of age estimates obtained from Largemouth Bass sagitta otoliths versus dorsal fin spines for Reader 1. Diagonal line represents comparisons where otolith age = estimated dorsal spine age. Circle size represents sample size of a particular age combination relative to the largest subsample.


Figure 6.  First and second Largemouth Bass dorsal spine annular radii (n = 114) as a function of age. Horizontal lines = median measurement for annulus 1 and 2. Analysis indicates overlap in young fish (i.e., 1 and 2-year olds). Position of first annulus was not consistent during aging of these young fish, leading to an overestimation of their ages.

I hope to further investigate these potentially non-lethal methods for aging LMB in additional waterbodies around the state of Florida to better understand dorsal spine growth. I also will be testing the survival of LMB after clipping their dorsal spines. I appreciate everything Florida Fish and Wildlife Conservation Commission (FWC) has done for me both as a student and as a biologist. I am grateful to AFS for providing this opportunity for me to share my research. Thank you for taking the time to read about my project, I hope you have plenty of questions. I am open to answering them! Feel free to contact me at summer.lindelien@ufl.edufor more information.


Beamish, R. J., and D. A. Fournier. 1981. A method for comparing the precision of a set of age determinations. Canadian Journal of Fisheries and Aquatic Sciences 38:982-983.

Campana, S. E. 2001. Accuracy, precision, and quality control in age determination, including a review of the use and abuse of age validation methods. Journal of Fish Biology 59:197-242.

Chang, W. Y. 1982. A statistical method for evaluating the reproducibility of age determination. Canadian Journal of Fisheries and Aquatic Sciences39:1208-1210.

Debicella, J. M. 2005. Accuracy and precision of fin-ray aging for gag (Mycteroperca microlepis) Master’s thesis, University of Florida, Gainesville, Florida.

Klein, Z. B., T. F Bonvechio, B. R. Bowen, and M. C. Quist. 2017. Precision and accuracy of age estimates obtained from anal fin spines, dorsal fin spines, and sagittal otoliths for known-age Largemouth Bass. Southeastern Naturalist 16:225-234.

Lin, L., A. S. Hedayat, B. Sinha, and M. Yang. 2002. Statistical methods in assessing agreement: models, issues and tools. Journal of the American Statistical Association 97:257-270.

Lin, L., A. S. Hedayat, and W. Wu. 2007. A unified approach for assessing agreement for continuous and categorical data. Journal of Biopharmaceutical Statistics 17:629-652.

Lin, L. I. 1989. A concordance correlation coefficient to evaluate reproducibility. Biometrics 45: 255-268.

Murie, D. J., D. C. Parkyn, C. C. Koenig, F. C. Coleman, J. Schull, and S. Frias-Torres. 2009. Evaluation of finrays as a non-lethal ageing method for protected Goliath Grouper Epinephelus itajara. Endangered Species Research 7:213-220.

Sikstrom, C. B. 1983. Otolith, pectoral fin ray, and scale age determinations for Arctic Grayling. Progressive Fish-Culturist 45:220-223.

Strickland, P. A., and C. R. Middaugh. 2015. Validation of annulus formation in Spotted Sucker otoliths. Journal of Fish and Wildlife Management 6:208-212.



My Summer Spent in Centipede Bay

by Cher Nicholson, University of Florida

My summer spent as an intern at Nature Coast Biological Station opened my eyes to the direct benefits that field work can bring to the environment. I learned that enhancement projects can be unique with respect to community involvement. The beginning stages of theenhancement project required permitting for the oyster reef location that involved both the Department of Environmental Protection (DEP) and the Army Corps of Engineers. In accordance with regulations, the chosenlocation for the artificial reef needed to be a specific distance from surrounding sea grasses, and it had to demonstrate adequate oyster recruitment capabilities. The site was chosen because it was within DEP’s standards, and experiments with tiles in Centipede Bay showed successful recruitment of oysters (Figure 1).  On deployment day, it was remarkable to see how many Hernando County volunteers contributed their time for prepping and deploying an artificial oyster reef (Figure 2).  After aiding in the construction of the artificial reef in April 2018, I was given the responsibility of monthly monitoring. I chose to measure salinity, temperature, pH, dissolved oxygen, reef area, and oyster recruitment, based on two oyster restoration manuals (Baggett et al. 2015), (Baggett et al. 2014). In addition to monitoring the reef, I was given the opportunity to go outside of my job description as an intern by conducting my own study!



Figure 1. Location for the deployment of the oyster reef in Hernando County, FL


Figure 2. Aerial view of reef deployment day with volunteer unloading bagged oyster shell from volunteer boats in Centipede Bay, FL

The main question for my study was based on the unique shape of the reef and if there was a difference in flow intensity in each subsection. I wanted to understand if a difference in flow intensity at seven unique sites on the reef had a correlation with oyster recruitment density. With a limited budget, clod cards and cubes made of hardened Plaster of Paris were used to calculate the relative flow intensity of the water based on the amount of dissolution of each cube placed in a standardized location. Clod cards were constructed using an ice tray, Plaster of Paris dry mix, and deionized water (Boizard and DeWreede 2006; Thompson & Glenn 1994). The standardized locations of the seven sites were constructed prior to the deployment of the cubes at 0.2 meters from the bottom. PVC pipe was used to construct the attachment site for the clod card and recruitment monitoring bag (Figure 3). Relative flow intensity of the seven sites were taken over the course of three months during summer 2018, with a deployment of three sets of clod cards. Photos were taken, and the mass was recorded for each clod card before deployment and after being submerged in the water for 72 hours (Figure 3). Clod cards lack the ability to calculate an accurate value for the velocity of the water on the oyster reef, but they offer a good estimate of relative flow intensity (Thompson and Glenn 1994). The relative flow intensity of each site can be calculated according to Thompson and Glenn (1994).


Sf= [ 1 – (Wf/ Wi)1/3]/θ

Sn= [ 1 – (Wf/ Wi)1/3]/θ

 Within their equation Wiis the initial mass, Wfis the final mass, Aiis the initial area, θ is time in days, Sf is weight loss data from cards deployed at the site, Snis weight loss data from cards exposed to water from the site.  The relative flow intensity can be calculated for each site using both the values for the clod card calibration (Sn), which accounts for dissolution of the cubes due to being submerged in water alone, and the change in mass of the cubes once submerged at the site and exposed to moving water for three days (Sf) (Thompson and Glenn 1994). This method provided a cost-effective way to demonstrate the relative flow of water within channels and on the reef.


Figure 3. Recruitment monitoring bag for Site 2 constructed with polyethylene cage material and filled with ten oysters shells that fit dimension requirement. Clod card is pictured in the upper left-hand corner of the bag


Figure 4. Clod card from Site 1 before (A,B) and after (C,D) deployment in May 2018

Initially, I hoped to compare the relative flow intensity at the seven sites with recruitment data from settling oyster spat, but with the vast amount of sediment that accumulated on the shells, there was no recruitment recorded for the summer spawning season. Instead of looking at recruitment, I shifted my study to analyzing the problem of sedimentation and if there was a correlation between relative flow intensity of the water and sedimentation. The cause of sedimentation on the reef was in question, so we devised a sedimentation experiment where four bags from each site would be cleaned using a water pump while four bags would be left untouched at each site. After, four cleaned bags and four untouched bags were placed interchangeably in a row of eight at each site. Photos were taken of each bag, totaling 56, after the cleaning and a month later.

The increase in percent sediment cover on the cleaned bags (over the course of a month) was not significantly different at each site (Figure 5). Once the clod card calibration value is calculated using water collected from the site, the numerical value for the relative intensity of water flow at each of the sites can be calculated. If there is a difference of relative flow intensity of each site on the reef, then a linear regression can be used to compare the relative flow value with the increase in percent cover of sediment at each site. This study will provide more information on how relative flow relates to sediment buildup on the reef and choosing the most effective sites for an artificial reef.


Figure 5. Average difference of percent sediment coverage in the experimental and control groups at each of the seven sites. Experimental bags were cleaned, and the control groups were untouched. The experimental bags did not show a significant difference in the percentage of reaccumulated sediments in a one-month period

I am very grateful for the opportunity to be involved with research as an undergraduate at the University of Florida. In addition to the opportunity to conduct my own study this summer, I gained valuable experience in field work, constructing my own materials for the study, and monitoring marsh grasses planted at Linda Pedersen Park as well as those at the nursery in Gulf Coast Academy in Hernando County, FL. I am eager to continue working on projects that both aim to enhance or restore the environment and involve the community.


Baggett, L.P., S.P. Powers, R.D. Brumbaugh, L.D. Coen, B.M. DeAngelis, J.K. Greene, B.T. Hancock, S.M. Morlock, B.L. Allen, D.L. Breitburg, and D. Bushek. 2015. Guidelines for evaluating performance of oyster habitat restoration. Restoration Ecology23:737-745.

Baggett, L.P., S.P. Powers, R. Brumbaugh, L.D. Coen, B.M. DeAngelis, J.K. Greene, B.T. Hancock, and S.M. Morlock. 2014. Oyster habitat restoration monitoring and assessment handbook. The Nature Conservancy, Arlington, VA, USA., 96pp.

Boizard, S.D., and R.E. DeWreede. 2006. Inexpensive water motion measurement devices and techniques and their utility in macroalgal ecology: a review. Science Asia 32: 43-49.

Thompson, T. L., and E. P. Glenn.1994. Plaster standards to measure water motion. Limnology and Oceanography39: 1768-1779.


Misperceptions of a giant: impact of the recovering Goliath Grouper on Florida reefs

by Christopher Malinowski, Florida State University

On April, 26, 2018 a public meeting was held by the Florida Fish and Wildlife Conservation Commission (FWC) to vote on a proposal to re-establish an extractive fishery for the Atlantic Goliath Grouper (Epinephelus itajara)—a species that has been recovering since it was afforded full protection in 1990, but that remains critically endangered throughout its range as declared by the International Union for the Conservation of Nature (IUCN). The meeting was rife with emotion. Public comment from those in favor of the re-opening and those against it was consistent with the series of public forums held around the state by FWC in summer months leading up to the April meeting in Fort Lauderdale, and of the many articles that surround this controversy.


Example article highlighting the controversial points of view on the presence of Atlantic Goliath Grouper on Florida reefs

Those in favor of re-establishing an extractive fishery claim that Goliath Grouper are a nuisance species, eating everything on the reef, and that removing some would improve the fisheries for spiny lobster and economically targeted reef fishes. Those opposed to a re-opened fishery, primarily dive operators and charter guides who already operate an active and non-extractive catch-and-release fishery, claim that Goliath Grouper have become a boon to ecotourism. They argue that killing Goliath Grouper would have a negative impact on their current business. With fear that their livelihoods are at stake due to policy decisions being made on this issue, those on either side may rely more on information and opinions that fuel their own confirmation biases rather than listening to the science, which holds the actual answers to these quarrels.

So what does the science show?

Unlike the misperception that Goliath Grouper are eating everything on the reefs and have a voracious appetite, they actually do not eat a lot relative to their size, which is due in part to their slow metabolic rate. Although they are capable of powerful bursts of speed, these cannot be sustained and therefore fast moving prey cannot be regularly captured. What they do primarily prey on are small fish and bottom-associated crabs that are much easier for a slow-moving Goliath Grouper to obtain. This is not to say that Goliath Grouper are not opportunistic predators, as are most large predators. They will occasionally take a free lunch if it is dangling at the end of a line or a spear. This is where the “nuisance” title comes from. Of the millions of people each year that target the very sites Goliath Grouper call home or aggregate to during the spawning season (peaks July-Sep), it is inevitable that there will be such encounters. However, these encounters often fare much worse for the Goliath Grouper than for the fisher as is evidenced by the high occurrence of fishing gear found in Goliath Grouper stomachs and mouths that sometimes prevent individuals from catching and digesting prey.

It is also untrue that Goliath Grouper negatively impact the lobster fishery. Lobster comprise less than 5% of Goliath Grouper diet, and fisheries data do not indicate a negative impact of increased Goliath Grouper abundance on spiny lobster abundance. There is, however, mounting scientific evidence for a positive relationship between the recovery of Goliath Grouper and the ecotourism industry. Goliath Grouper have become an iconic fish in Florida for people to dive with and fish for, using non-extractive catch-and-release methods—there is nowhere else in the world that offers the opportunity to dive with such large aggregations of giant fish. This has boosted business not only for the dive and charter fishing industries, but also local businesses, airlines, and numerous other tourism-related businesses that benefit from statewide, nationwide, and international travelers who visit Florida in order to interact with these giants.


Adult Goliath Grouper stomach content data, shown by % weight and % occurrence (data source: Malinowski et al. (unpublished data)). Images are of actual retrieved stomach contents

There is scientific evidence that Goliath Grouper have a positive impact on reef communities because they play a role as ecosystem engineers whereby their excavating behavior maintains and creates new habitat. The result of this is greater species richness and abundance of economically important species, like snapper.

My ongoing research objectives, and that of my colleagues, is to continue working with Goliath Grouper to answer many of these important ecological questions, and to better inform managers, policy decision makers, and the public with the hope of moving away from emotionally-driven policy decisions and toward more science-based decisions.

Much of my current work is also focused on measuring mercury levels in various tissues of Goliath Grouper and developing a better understanding of spatial patterns and the negative effects of the high levels we are finding —levels that are much higher than is safe for human consumption. Colleagues and I currently have multiple manuscripts in review related to mercury in this species, and on the misperceptions and current political process surrounding Goliath Grouper, so stay tuned to find out more.


How to identify the ploidy of an oyster using a flow cytometer

By Yanqing Zeng, UF PhD student

I just transferred to University of Florida from Auburn University last semester. My research field changed from catfish to oysters and hard clams. There are many differences between the two labs. The biggest one to me is that when I focus on catfish, I was more like a “fisherman” and now doing shellfish research I’m more like a “scientist.”

The main reason I feel this way is that I’m now using some “modern” laboratory equipment. My interests lie in flow cytometry. Flow cytometry is a technique to measure the volume of cells in a rapidly flowing fluid stream as they pass in front of a viewing aperture. A flow cytometer is similar to a microscope, but unlike a microscope producing an image of the cell, flow cytometry offers high-throughput, large-scale, automated quantification of specified optical parameters on a cell-by-cell basis.

flow cytometer

Flow cytometer

One main program I’m working on is tetraploid oyster breeding. Scientists used to identify ploidy by counting the number of chromosomes. With a flow cytometer, we can identify the ploidy quickly and accurately. Let me walk you through the process.

Extraction: If we only want to identify ploidy, we just open the shell carefully and cut a small piece of adductor muscle. To extract a sample in vivo (keeping the oyster alive after extraction), we dig a small hole on the hinge ligament then use a 21-G needle with syringe to withdraw the sample from the adductor muscle.

Stain: Cut the samples into small pieces to dissociate cells and then pour them in a tube with Propidium iodide (PI). Stain for 5 minutes. PI cannot cross a living cell’s membrane, making it useful to distinguish necrotic, apoptotic, and healthy cells.

Washing: After staining, we pour the solution through a 50μm nylon mesh and transfer into a microtube. We make sure we only get the suspension. Efficient and effective flow cytometry analysis needs a sample to be a single-cell suspension. Even a tiny muscle piece could block the fluidics system.

Testing: This is the easy part. Open the flow cytometer software (BD Accuri C6) and set the parameters: Run with limits of 10,000 events through slow flow rate. Then we get the result in seconds!

cytometry software

Analysis: Diploid organisms carry two complete sets of chromosomes and triploid organisms carry three complete sets of chromosomes. So the DNA content is different between diploids and triploids. Fluorescence intensity is proportional to the amount of DNA content. A triploid oyster’s DNA content is 1.5 times more than a diploid one.

Compared with chromosome counting techniques, flow cytometry is much faster and more convenient. So if you want to identify an organism’s ploidy, use a flow cytometer!

The African Clawed Frog: New invasive species in Florida

By Allison Durland Donahou, Doctoral Student at the University of Florida


Xenopus laevis (Source: University of Rochester)

African Clawed Frogs Xenopus laevisare a recent invader to Florida and were discovered by Drs. Hill, Tuckett, and Lawson at the University of Florida (Hill et al. 2017). While X. laevishas invaded all over the world, a reproducing population was not discovered in Florida until 2016. African Clawed Frogs are unique in that they have a fully aquatic life cycle. They are native to South Africa, but have been shipped around the world since the 1930s for use as a model organism for vertebrate structure and developmental biology (Van Sittert and Measey 2016). Additionally, X. laeviswas used for pregnancy testing before the modern tests we have today were developed (Gurdon and Hopwood 2000). When female frogs are introduced to water with a dilute amount of urine from a pregnant woman, the frogs will lay eggs within hours. This was used to determine if a woman was pregnant. Since modern pregnancy tests were developed, these frogs were no longer needed and were disposed of. Most introductions of these frogs are from laboratories, but some come from the pet trade, as well. The source population for almost all the frogsused as a model organism are from a region in South Africa called Jonkershoek. Van Sittert and Measey (2016)analyzed export records to determine where these frogs were shipped to and from (Figure 1).


Figure 1. Distribution of Xenopus laevisper decade. Records are from publications (circles), shipments from South Africa (squares), and reported invasive populations (triangles).

A variety of experiments are being conducted on the African Clawed Frog at the Tropical Aquaculture Laboratory, including predation on X. laevis tadpoles by a variety of fish species and life history tradeoffs between domestic and wild populations of frogs.


Experimental tank set up of Xenopus laevispredation study.

Additionally, researchers are evaluating the population dynamics and movement of X. laevisin the Riverview area (area of first introduction/reproduction). Through these projects, we hope to learn more about the potential effects of this new invasive population in Florida.

For more information about this project, feel free to contact Allison at



Gurdon, J. B., and N. Hopwood. 2000. The introduction of Xenopus laevis into developmental biology: of empire, pregnancy testing and ribosomal genes. International Journal of Developmental Biology 44:43–50.

Hill, J. E., K. M. Lawson, and Q. M. Tuckett. 2017. First record of a reproducing population of the African clawed frog Xenopus laevis Daudin, 1802 in Florida (USA). BioInvasions Records 6(1):87–94.

Van Sittert, L., and G. J. Measey. 2016. Historical perspectives on global exports and research of African clawed frogs (Xenopus laevis). Transactions of the Royal Society of South Africa 71(2):157–166.

Unlocking the mysteries of shark reproduction

By Kat Mowle, UNF MS Student

If you grew up watching Jaws, there’s a good chance you fear sharks when you go swimming in the ocean. In reality, the vast majority of sharks are completely harmless, and you are more likely to be struck by lightning than die from a fatal shark attack. If you think about it, sharks actually have more of a reason to fear us than we have to fear them, because many shark populations are in decline due to factors like overfishing, pollution, and loss of habitat. Shark and ray species are more vulnerable to overexploitation than bony fish are because sharks tend to mature at a later age, produce fewer offspring, and grow slower. Additionally, mating events for some shark and ray species may occur only every two to three years. All of these factors combined mean that sharks and rays are particularly vulnerable to overexploitation, and it is absolutely critical that we work to understand the biology and life history of these organisms so we can better manage their populations (Hoenig and Gruber, 1990; Stevens et al., 2000).

Traditionally, understanding the reproductive cycles of sharks has required lethal sampling in order to examine changes in their reproductive tracts throughout the year. This approach is unsustainable for threatened species, and cannot be used for endangered species (Hammerschlag and Sulikowski, 2011). In more recent years, scientists have moved to developing non-lethal methods for assessing reproduction of sharks and rays, which is what my advisor, Dr. Jim Gelsleichter, works on at the University of North Florida. Ultrasonography can be used to determine pregnancy, just like with humans. Scientists are also able to measure the concentrations of reproductive hormones in the blood of sharks to determine when various reproductive events occur. For male sharks, high plasma concentrations of testosterone occur during the peak time of sperm production, indicating when a male is capable of mating. For females, high concentrations of estrogen (E2) correlate with the development of eggs in their ova, indicating when a female is ready for fertilization and pregnancy (Awruch et al., 2008; Awruch, 2013; Sulikowski et al., 2007).

While these methods have proven to be useful for many species, analyzing only E2 does not always provide researchers with the full picture of a species’ reproduction. As mentioned earlier, some shark species only reproduce every two or three years. How often an individual reproduces is referred to as reproductive periodicity, with females that reproduce every year termed annual, every two years biennial, and every three years triennial. For females of species with more unusual patterns of reproductive periodicity, examining levels of E2 in their plasma doesn’t always give the full picture of their reproductive cycle. This is where my research comes in. My master’s research focuses on measuring vitellogenin (Vtg) in the plasma of elasmobranchs, specifically focusing on the bonnethead shark, Sphyrna tiburo (Figure 1).

figure 1.jpg

Figure 1. Bonnethead shark (Sphyrna tiburo) specimen

Vtg is a protein that is produced by the liver during the time of follicular development, when female sharks have new ova developing in their ovaries. Thus, determining when Vtg is produced is a good indicator of when follicular development occurs. If researchers are able to couple measurements of plasma Vtg with a nonlethal determination of pregnancy (such as ultrasonography), then a new nonlethal method for determining reproductive periodicity can be developed. For example, if a female has Vtg present in her plasma during pregnancy, that indicates the female will have eggs ready to be fertilized after she gives birth, and thus she will likely give birth again the next year. So this female would be an annual reproducer. On the other hand, if a female does not have Vtg present during pregnancy, she will likely need to take time off to grow eggs before she is ready to mate again; such a female would likely be a biennial or triennial reproducer. These measurements do depend on the length of a female’s gestation period, as the bonnethead shark is an annual reproducer, but does not produce Vtg during pregnancy. However, this species has a fairly short gestation period of only 4 to 5 months, giving females time to develop new eggs and still be able to mate and give birth every year.

My research focuses specifically on measuring Vtg in the plasma of female bonnethead sharks and characterizing the process in this species. In order to do this, I collect blood samples from female bonnethead sharks out in the field (Figure 2). I then centrifuge the blood to separate the plasma and analyze the plasma for the presence of vitellogenin using a process called Western blotting or immunoblotting. This process doesn’t give us quantitative results, but is a good method for determining whether or not Vtg is present in the plasma of a female bonnethead shark.

figure 2

Figure 2. Obtaining a blood sample from a mature female bonnethead shark.

We ultimately were able to detect both Vtg itself and a likely component protein (lipovitellin, or Lv) in the plasma of female S. tiburo. Since it is known that Vtg breaks down fairly quickly if plasma is not stored immediately or not stored with a protease inhibitor, we chose to classify females with only the Lv component protein in their plasma as also likely producing Vtg (Figure 3). It was determined that the proteins being detected were likely Vtg (~200 kD) and Lv (~70 kD) based on what had been observed for another elasmobranch species (Perez and Callard, 1992).

Figure 3

Figure 3. Immunoblots showing the detection of Vtg and Lv within the plasma of female S. tiburo. a) Detection of Vtg within plasma of females sampled in March (Lanes 2-8) and early May (lane 12). b) Detection of Lv within the plasma of mature female S. tiburo. The Lv protein is outlined in the boxes.

Looking at both the detection of Vtg and Lv as evidence of Vtg production occurring, it was determined that the highest numbers of females were producing Vtg in March and April, which matches previous studies on this species (Parsons, 1993). The protein was also produced in May for one individual. What was interesting was we found evidence of the protein’s production beginning as early as August for some individuals, with the protein continuing to be found in the plasma from August to December (Figure 4).

Figure 4

Figure 4. Proportion of mature S.tiburo females that were determined to have either vitellogenin or the putative lipovitellin protein present within their plasma during each month.

This finding suggests that female bonnethead sharks begin developing new eggs within their ovaries immediately after they give birth; production is not limited to the spring time period, which was suggested by previous studies that focused on when the highest number of large yolky eggs were observable in the ovaries. The variations we observed in when Vtg was produced are likely due to variations between populations. It has been observed, for example, that females in populations in South Florida give birth earlier than those in North Florida, which would explain why Vtg production is observed in August for females in South Florida but not until October for females captured in South Carolina (Lombardi-Carlson et al., 2003).

As I have been conducting my master’s thesis research, we have also been testing whether we can measure Vtg in the plasma of other elasmobranch species. We focused on the bonnethead because our antibody against Vtg was developed specifically for this species. But, as noted, measurement of Vtg would be particularly useful for clarifying the reproductive periodicity of other species, such as the blacknose shark (Carcharhinus acronotus), which seems to be capable of both annual and biennial reproduction in the Atlantic (Driggers et al., 2004). Measuring the concentrations of E2 in the plasma of this species does not effectively answer questions about the reproductive status of females of this species; researchers are unable to determine if a female is resting or reproductively active.

So far we have confirmed that we are able to measure Vtg (or at least component proteins of the larger Vtg protein) in the plasma of eight other elasmobranch species. These results indicate that the methods I have developed in my study will be useful for studying reproduction of other species. Particularly, these methods will be a good nonlethal method for characterizing reproductive periodicity. Having a good understanding of exactly how often a species reproduces is critical to management of a population, as the population growth depends on how many females are actually contributing to the next generation in a given year. Thus, the methods developed specifically throughout my master’s thesis will hopefully continue to be used and will act as an ideal new nonlethal method for determining reproductive periodicity, providing crucial information about a species’ reproduction to managers.

UNF Shark Biology Facebook Page



Awruch CA, SD Frusher, NW Pankhurst, and JD Stevens. 2008. Non-lethal assessment of                reproductive characteristics for management and conservation of sharks. Marine              Ecology Progress Series 355: 277-285.

Awruch CA. 2013. Reproductive endocrinology in chondrichthyans: the present and the                future. General and Comparative Endocrinology 192: 60-70.

Driggers WB, DA Oakley, G Ulrich, JK Carlson, BJ Cullum, and JM Dean. 2004.                                    Reproductive biology of Carcharhinus acronotus in the coastal waters of South                    Carolina. Journal of Fish Biology 64(6): 1540-1551.

Hammerschlag N and J Sulikowski. 2011. Killing for conservation: the need for                                alternatives to lethal sampling of apex predatory sharks. Endangered Species                      Research 14: 135-140.

Hoenig JM and SH Gruber. 1990. Life-history patterns in the elasmobranchs:                                    implications  for fisheries management. In Elasmobranchs as Living Resources:                 Advances in the Biology, Ecology, Systematics, and the Status of the Fisheries.                       Proceedings of the Second United States–Japan Workshop East–West Center,                         Honolulu, Hawaii, 9–14 December 1987, pp. 1–16. Ed. by H. L. Pratt, S. H. Gruber,                 and T. Taniuchi. NOAA Technical Report NMFS 90. 518 pp.

Lombardi-Carlson LA, E Cortés, GR Parsons, and CA Manire. 2003. Latitudinal variation              in life-history traits of bonnethead sharks, Sphyrna tiburo, (Carcharhiniformes:                   Sphyrnidae) from the eastern Gulf of Mexico. Marine and Freshwater Research,                 54(7): 875-883.

Perez LE and IP Callard. 1992. Identification of vitellogenin in the little skate (Raja                       erinacea). Comparative Biochemistry and Physiology 103B(3): 699-705.

Parsons, GR. 1993. Geographic variation in reproduction between two populations of the           bonnethead shark, Sphyrna tiburo. In The reproduction and development of sharks,             skates, rays and ratfishes (p. 25-35). Dordrecht, Springer.

Stevens JD, R Bonfil, NK Dulvy, and PA Walker. 2000. The effects of fishing on sharks,                   rays, and chimaeras (chondrichthyans), and the implications for marine                               ecosystems.  ICES Journal of Marine Science 57(3): 476-494.

Sulikowski JA, WB Driggers III, GW Ingram Jr, J Kneebone, DE Ferguson, and PC Tsang.               2007. Profiling plasma steroid hormones: a non-lethal approach for the study of                 skate reproductive biology and its potential use in conservation management.                     Environmental Biology of Fishes 80(2-3): 285-292.

Field Surgery as a Five Foot “Tall” Woman

By Beth Bowers, FAU PhD Student


Often we enter into graduate school with a broad idea of what we might be doing. If you’re anything like me, you received a swift slap to the face when you realized that YOU were solely responsible for figuring out the logistics of your project. Logistics are always the enemy. The only certainty that grad school affords you is that Plan A will be a miserable failure time after time. Then, there are the logistics of being a small woman in the field of fisheries. Whether we like it or not, we live in a man’s world where all of the equipment was designed for those with upper body strength, so you’d better get buff if you want to run with the boys or… you could get clever.

After being accepted at Florida Atlantic University, I soon found out that my doctoral dissertation, which consists of studying the migratory pattern of the blacktip shark, also includes recruiting volunteers, managing training records, completing IACUC amendments, changing the power steering on the boat, performing a surgery while leaning off the side of a boat while Sunday Palm Beach boaters and paddle boarders take pictures…but, I’m getting off topic. Here, I will offer a solution to those eager, useful yet underestimated, a little shorter than average, women in the field of fisheries/shark research.

Many job postings will state that you must be able to lift 70 lbs. or some other amount of weight that would require ant-like strength from your tiny body. When trying to appear as equally useful as your male counterpart, it helps to utilize the pully system whenever possible. For instance, when drum lining, utilize the gunwale as leverage, as long as there are no dents or scuffs in the fiberglass that can cause the rope to fray. Don’t be too proud to let the 6’6” man beside you help you. Be useful in other ways. Find something else to do and let him use his natural-born leverage to pull in the line. When long lining, let the boat do most of the work. Don’t try to pull the boat toward the line, pull in the slack of the line as it comes to you. This advice applies to the men on the boat as well but, we’re not addressing them at the moment. Build up your grip strength! There is no better way to show your worth on a research vessel than to unclip 60 tuna clips without faltering.


Mike McCallister, the not so hypothetical 6’6″ man beside you

Now, you’ve caught a shark that’s longer than you are tall, what do you do? Do you stand back and let the men secure it? Absolutely not. You find clever ways of navigating around your “shortcomings.” Always have someone else holding the tuna clip in case the shark gets away from you. Prepare a tail rope by making a loop out of one of the deck lines that can be quickly tightened. Understand physics. A shark has evolved to remain horizontal in the water column. In the water, pectoral and dorsal fins behave as lifting surfaces. Out of the water, these lifting surfaces are useless so keep the shark in the water. To reach the tail, the head of the shark must be lower than the caudal fin, like a see-saw. Walk the shark like a dog on a leash alongside the vessel. Ask a colleague to use a little force and to persuade the shark to swim in a circle. This will help to keep the shark swimming rather than becoming a vertical dead weight. When the shark gets close to the boat, have them shorten the length of the gangion but do NOT pull the head above the water’s surface. As your colleague shortens the length of the gangion, the shark will swim or glide alongside the vessel.

At this time, you should have your looped deck line in hand and the loop should be big enough to fit around the entire height of the heterocercal caudal fin. As the shark’s tail end approaches, reach into the water from the stern of the boat, grab the caudal fin, and slip the deck line over the tail. Your colleague should keep the gangion taut to prevent the shark from turning around and biting you. Once the line is tight around the caudal peduncle, tie off the tail rope to the stern cleat of the boat, leaving enough slack for the shark to remain halfway under the water’s surface. This not only frees your hands from having to hold the shark, it keeps your crew at the stern of the boat, the only place where you can reach the water. You should be able to release the tail rope quickly in case the hook rips out of the mouth or a crimp on the gangion fails. This CAN and WILL happen. If you have ever had a timid undergraduate help you with repairing broken gangions, you already know this. Use an additional deck line as a mid-body rope. Most people can lean off the side and reach around the body of the shark to feed the tightening end of the deck line into the loop; I cannot…unless I feel like going for a dip in the ocean. Instead, I make a large loop in the deck line and feed it over the free end of the gangion. I then slip the loop over the head and pectoral fins of the shark, position the line anterior to the dorsal fin, and posterior to the pectoral fins.


Securing a tail rope on a blacktip shark

Once you have the shark secured, prepare your surgery equipment. Thread the monofilament suture into the end of a reverse cutting suture needle. In my experience, a tapered edge suture needle will dull halfway through the procedure. Fill a syringe with lidocaine and inject it into the musculature on the anterior and posterior sides of the planned incision site. This is a good time to let the crew take measurements, a DNA fin clip, tissue samples, and insert an external dart tag. Don’t be a hero. Let them do it. Your back will take enough of a beating during the surgery. When you are ready for surgery, assign someone to play nurse and someone to help hold up the shark. You should also ask someone to be on watch for wakes. You’ll understand why I say that when you almost flip into the shark’s mouth the first time a wake passes. The nurse should be ready with the hemostats and suture needle. The shark holder should spare his/her back as much as possible by adjusting the mid rope and standing on the slack of the rope that is in the boat. You are again employing the pully system; good for you. This allows the holder to stand upright for most of the procedure and prevents him/her from grunting and whining in your face while you hang off the side of the boat and play doctor. Let your “nurse” pass you the next instrument and take the used one out of your hand. It helps if you teach your crew to pass you the instruments in the orientation in which you will use them, just as a nurse does to a non-shark surgeon.


Boatside inversion

Lean over the side of the boat…hope you’re not feeling nauseous because you are basically inverted. Get ready for a hamstring workout. Make an incision midway between the pelvic fins and pectoral fins along the ventral midline. If you make the incision just large enough to fit the transmitter, then you only need one suture to close the incision. Your hamstrings will thank you. Use the blunt end of the scalpel handle to ensure that you have penetrated the abdominal cavity; through the skin, muscle, and peritoneum. Double check that the transmitter ID number has been recorded. You WILL forget to do this. If anyone who works with acoustic tags tells you they have never forgotten to record the ID code, he/she is a filthy liar and is never to be trusted again. You can forget once per day and figure out the code by process of elimination back at the lab, but not twice. Insert the transmitter into the incision.


Hemostats holding a suture needle

Use the hemostats to insert the suture needle into the incision and back out through the side closest to you. Do so by moving your wrist in a scooping motion towards your body. Don’t poke yourself in the finger with the dirty suture needle as it exits the incision margin. When pulling the suture needle through, be careful not to allow the suture thread to slip out of the incision – starting over at this phase is not ideal. You can ensure that it will not slip out by clipping a pair of hemostats onto the free end of the suture monofilament before pulling the suture needle through. Close the incision with a surgeon’s knot. View a helpful video here: At this point, your hamstrings feel like they’re going to rip through your skin. Flip the shark into the upright position, dorsal side up. Remove the hook from the mouth. Synchronize the loosening of the mid rope and the tail rope. Hold the dorsal fin until the shark awakes. Release the shark by allowing it to swim through the large loops you have created in the deck lines. Make sure the loops stay large until the caudal fin is free from entanglement with each deck line. God help you if you have the shark by the tail only; I have no advice for that situation.

Congratulations, you have just tagged a shark that is bigger than you are. Now stretch it out and suck it up because it’s peak fishing season and you’ll have nine more to do today!

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