Commercial turtle harvest is unregulated in Iowa for several species. The Iowa DNR is considering beginning to regulate the turtle harvest. Specifically, the DNR proposes closing the turtle harvest season through mid-July, which would reduce the harvest of adult females. The DNR's white paper outlines the issue and proposed regulations, and can be downloaded with the link. Some commercial harvesters oppose these regulations, but I am in strong support of them. Below is the letter I wrote to the DNR supporting increased turtle regulations.
I'm writing as a "non-consumptive" stakeholder in regards to the proposed commercial turtle harvest regulations. I consider myself a stakeholder in this issue because I study turtles both within the state of Iowa, and on the Mississippi river on the Iowa/Illinois border. I earned my PhD from Iowa State in the Ecology and Evolutionary Biology program and currently am a postdoctoral researcher at Iowa State. All of the research related to my dissertation and current job is on turtles. I am also a taxpayer and purchase hunting/fishing licenses in the state of Iowa each year, and as such I am concerned that our state resources are managed properly, and not exploited for financial gain by a few.
I support the proposed regulations (closing the season each year until mid-July) for multiple reasons. First, I have read and agree with the primary findings of the IA DNR's paper "Iowa's Commercial Turtle Harvest". As stated in the paper, harvesters tend to target larger individuals, and often females. Multiple lines of scientific evidence strongly indicate these mature adults are the most valuable individuals in the population. Thus, from a managment perspective these are also the most important to conserve. Secondly, the turtle harvest is alarmingly high, and has been steadily increasing. This is mirrored by a reduction in catch per license. Thus, there is already evidence of the negative impact of harvesting on Iowa's turtle populations, and if unchecked, could be catastrophic for turtle populations.
Additionally, the analyses in the paper likely underestimates the impact of harvesters on turtle populations. I understand that harvesting efforts were concentrated in only a few parts of the state in the late 80s, and have since expanded across much of the state. This pattern suggests harvesters are targeting "virgin" waters, and this spatial pattern is not specifically accounted for in the white paper's analyses. As an analogy, if timber harvesters were clear-cutting across a fully forested state unchecked, diminishing returns wouldn't be documented until most of the state resource has actually been removed, and it was too late to implement sustainable strategies. As turtle populations are notoriously difficult to monitor, the exploitation of the resource would not be nearly as apparent as in the forestry analogy. The DNR should be commended for their initiation of the turtle monitoring program.
I do not support any commercial turtle harvest in the state of Iowa. Neighboring states have appropriately reduced or eliminated commercial harvest. However, if Iowa envisions commercial turtle harvest as an important part of its economy, it ought to manage the resource sustainably. The story of overexploitation and collapse of natural resources has repeated itself countless times in recent history, and we know long-lived, slow to mature organisms are most vulnerable to overexploitation. Thus, in the interest of keeping a sustainable turtle harvest industry in the long-term future, Iowa must drastically reduce turtle harvest now. Otherwise, future and even current generations of turtle harvesters will be unable to viably utilize the resource.
Finally, it seems to me that the commercial turtle harvester's may be making substantial profit on a public resource. The DNR will sell a single non-resident deer license for $426, yet a resident harvester can have unabated access to the turtle population for $100. I do not know the profit trappers are making off this public resource, but it seems that is a fairly low fee considering the profit they may make, and the harm they induce on everyone's resource. If commercial turtle harvesting continues, the DNR should consider increasing license fees, or taking a percentage of sales (harvesters who take more, pay more).
Again, thanks for facilitating the meeting yesterday, and I would like my voice to be heard in the law-making process. Please let me know if there are other things I can do, or other people I should contact in this regard. I am writing this in the hopes it will help pass the proposed regulations, so please use this letter as you see fit to support the regulations.
Turtle Ponds at the Hort Farm
It’s fairly straightforward to do research on many critters in the lab: insects, small fish, mice, and many lizards will readily reproduce in a small aquarium or cage in your laboratory. That’s not always the case though. The Janzen Lab studies painted turtles and we want to be able to manipulate some aspects of their environment that are impossible to manipulate in the wild, yet we can’t do it in the lab either. That is why we have created our turtle ponds at the Iowa State Horticulture Research Farm. We now have 4 turtle ponds, each with associated nesting habitats. These ponds are turtle proof (turtles can’t get in or out) and raccoon/skunk proof. They will be excellent for a variety of experiments that no one else has been able to do before because of the large logistical obstacles we have overcome.
Designing and constructing these ponds took a lot of creativity, trial and error and sweat! We have used other ponds before (For Jeanine’s research: http://www.public.iastate.edu/~fjanzen/pdf/12BiolConserv2.pdf), and I used earlier versions of these ponds for a recent experiment (manuscript being written, preliminary results here: (http://fpr.extension.iastate.edu/pdf/2012/EffectsOverwintering.pdf ). Learning from some of the issues we had with these earlier experiments, we have (hopefully) perfected our design. Fence durability was a concern before; the current ponds have a sturdy, hog-fence perimeter, which supports PVC paneling that turtles cannot get under nor climb over. And these fences are resilient to our lovely Iowa weather that includes high winds, heavy rains, and snow drifting during winter. Outside the hog fence is electric fencing, which keeps the mammalian predators at bay. The ponds are divided by removable PVC fence panels, which will allow us to easily change the pond set up for future experiments. The ponds themselves are ~1.5 meters deep and large enough to keep a lot of turtles happy, and there is ample terrestrial nesting habitat nearby. We can drain these ponds to easily retrieve turtles in the fall (we hibernate them in the lab).
These ponds were only possible through a tremendous amount of help from a lot of people. Nick Howell, Jeff Braland and others at the Hort Farm were extremely helpful in helping us plan and implement our design. Members of the Janzen lab and other volunteers provided plenty of elbow grease to get the job done. The facilities are funded by the NSF and ISU Research Farms, directed by Dr. Mark Honeyman.
What is the general focus of our research?
Painted turtles have temperature-dependent sex determination. The temperature an egg experiences during incubation will determine if the embryo will develop as a male or female. Nests experiencing warm temperatures will produce all females, where nests experiencing relatively cool temperatures will produce all males. Intermediate nest temperatures produce both sexes. We know from prior research that the mother (who abandons eggs after nesting) can partially influence her nest temperature by choosing where to nest. Generally, we are very interested in how turtles will respond to climate change. Will warming climates produce highly female biased populations? Will turtles be able to keep a healthy, balanced sex ratio as climates change? If so, how? Is it through long-term evolutionary changes in the populations, or through shorter term plasticity?
What is our current project at the ponds?
We are very interested in whether environmental factors experienced by female turtles will influence her reproductive decisions (i.e. where/when to nest, what resources will she allocate to eggs, etc.). We have already tested whether overwintering conditions influence the timing or placement of nests (see link above for preliminary findings). We are currently testing whether the adult sex ratio experienced by the female influences her nesting decisions. To do this, we have 10 female turtles in each of the 4 ponds, but we have different numbers of male turtles, such that the adult sex ratio varies. The most male biased pond is 3:1 (M:F) and the most female biased pond is 1:4. We will also see if these treatments influence female stress levels, and if it influences resource allocation to eggs (i.e. will mothers in a male biased population deposit different levels sex hormones in her eggs?). Next summer during nesting season, we expect that turtles in male biased ponds will select sunny nest sites, which will be more likely to produce females. We expect the opposite pattern in the female biased ponds (females will nest in shady areas to produce males). The turtles are in the ponds now, but we are excited for nesting season next year when this experiment will really be underway!