Protecting Species Through Legislation: The Case of Sea Turtles

Agustín Pérez-Barahona, Eric Strobl, “Protecting Species Through Legislation: The Case of Sea Turtles”, Sustainable Future Policy Lab: Analyses, 2020-002.


While species protection in the US is arguably the most extensive in the world, there is mixed empirical evidence as to whether it has actually been effective. We use the case study of loggerhead sea turtles in Florida to show that legislation can indeed be an effective tool for species preservation. We also show that legislation, at least in the case of loggerheads, may be much less costly than alternatives.

Estimates suggest that up to 539 species have become extinct in the US over the past 200 years.  Yet, while there had been a growing awareness of the extinction threat to a number of prominent species since the turn of the 19th century, prior to the Endangered Species Act in 1973 (ESA) no general protective legislation had been put in place.  The ESA potentially provides extensive protection for species listed, including protection of critical habitat, implementation of a recovery plan, restrictions on take and trade, authorization to make land purchase or exchanges for important habitat, and federal aid to State and Commonwealth conservation departments.  As matter of fact, as of date over 2,400 species have made it on the ESA’s endangered species list, and current annual expenditure on their conservation are over US$ 1.5 billion. This begs the question as to how effective the ESA has been in terms of facilitating species recovery.

One has to recognize of course that in practise implementation of an effective species recovery plan is not necessarily straightforward since habitats are not always easily defined, threats are often multi-faceted, monitoring can be difficult, and implementation can be costly, both more generally and in terms of opportunity cost. A representative case in point of these challenges is the loggerhead sea turtle. More specifically, sea turtles are threatened by a number of factors, including entanglement in fishing gear, poaching and illegal trade of eggs, meat, and shells, ocean pollution, and coastal development, their population is widely believed to be decreasing at an alarming rate worldwide. A crucial part of the threat of coastal development to loggerheads is the presence of artificial lighting on their nesting beaches, where there has been considerable evidence that shows that artificial nighttime light deters sea turtle adults from nesting and disorients them. Moreover, artificial lighting also increases the mortality rate of sea turtle hatchlings because it interferes with hatchlings’ ability to find their way from their nests on the beach to the sea

While loggerheads have been ESA listed and hence protected since 1978, with current annual expenditures of nearly 9.5 million USD, it is not clear how effectively they are protected.  In Florida, which hosts 90 per cent of nesting activity in the US, they enjoy additional protection under the 1995 Florida Marine Turtle Protection Act (MTPA), which specifically prohibits, amongst other things, the “take” of loggerhead turtles, where “take” includes their harassment and harm.  As confirmed by a ruling of a federal appellate court in 1998, artificial light on beaches during their nesting period falls under this definition of “take” and hence can be viewed as prohibited by both the ESA and the MTPA. Additionally, the Florida Department of Environmental Protection (DEP) has enacted rule 62B-55 F.A.C., setting forth a set of guidelines for local government regulations that control beachfront lighting to protect nesting females and hatching sea turtles.  However, importantly, the DEP sea turtle lighting rule does not require local governments to legally adopt the proposed guidelines. While presently most Florida coastal counties and municipalities have meanwhile adopted some form of beach lighting ordinances, their ordinances differ widely not only in terms of their legislative details but also in their effectiveness of implementation.

In this study we explicitly set out to study how effective the sea turtle friendly lighting legislation (STFL) has been and what the monetary benefits are.  To this end we build a time-varying county level STFL ordinances index that takes the intricacies of the legislative pieces and their implications for sea turtle nesting into account.  We combine this with information on local nesting activity over 26 years and 200+ beaches, which we use to econometrically quantify the effectiveness of the ordinances. We find that the legislation has indeed been effect in encouraging nesting activity of loggerheads.  With this estimate in hand, we employ a calibrated population model for loggerheads to assess the effect of STFL ordinances on the evolution of their population over the long term. Our findings are shown in Figure 1 show that compared to having no ordinances the current situation reduces the years to extinction by 10 per cent, but that increasing ordinances to their maximum potential effectiveness (currently Florida counties are on average only 42 per cent effective) would add a further 19 years to their overall survival as a species (in Florida). 

Figure 1: Population Dynamics of Loggerhead Turtle Population under Current and Counter-Factual Scenarios

Finally we use our results to put a monetary value on the STFL legislation. To this end we compare the number of turtles saved to how much it would cost to raise them in captivity to then be released into the wild.  We find that the costs of such an alternative strategy would range between $US 17 and 39 billion per year, i.e., between 1.8 and 4.2 per cent of Florida’s GDP. Taking a range of willingness to pay estimates derived from the existing literature we show that the Florida public is, however, likely to be ready to only finance at most 4.5 per cent of such a program.


Brei M., A. Pérez-Barahona and E. Strobl (2019), “The Effectiveness of Protecting Species Through Legislation: The Case of Sea Turtle Lighting Ordinances”, American Journal of Agricultural Economics.

Brei M., A. Pérez-Barahona and E. Strobl (2016), “Environmental Pollution and Biodiversity: Light Pollution and Sea Turtles in the Caribbean”, Journal of Environmental Economics and Management, 77, 96-116.

Cite as
Agustín Pérez-Barahona, Eric Strobl, “Protecting Species Through Legislation: The Case of Sea Turtles”, Sustainable Future Policy Lab: Analyses, 2020-002.

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