title: Evidence of size-selective evolution in the fighting conch from prehistoric subsistence harvesting.
abstract: Intensive size-selective harvesting can drive evolution of sexual maturity at smaller body size. Conversely, prehistoric, low-intensity subsistence harvesting is not considered an effective agent of size-selective evolution. Uniting archaeological, palaeontological and contemporary material, we show that size at sexual maturity in the edible conch Strombus pugilis declined significantly from pre-human (approx. 7 ka) to prehistoric times (approx. 1 ka) and again to the present day. Size at maturity also fell from early- to late-prehistoric periods, synchronous with an increase in harvesting intensity as other resources became depleted. A consequence of declining size at maturity is that early prehistoric harvesters would have received two-thirds more meat per conch than contemporary harvesters. After exploring the potential effects of selection biases, demographic shifts, environmental change and habitat alteration, these observations collectively implicate prehistoric subsistence harvesting as an agent of size-selective evolution with long-term detrimental consequences. We observe that contemporary populations that are protected from harvesting are slightly larger at maturity, suggesting that halting or even reversing thousands of years of size-selective evolution may be possible.
authors.affiliation: Smithsonian Tropical Research Institute, , PO Box 0843-03092, Balboa, Republic of Panama, Cofrin Center for Biodiversity, University of Wisconsin-Green Bay, , Green Bay, WI 54311, USA, Institute for Tropical Ecology and Conservation, , 2911 NW 40th Place, Gainesville, FL 32605, USA, Zooarchaeology Laboratory, The Cotsen Institute of Archaeology at UCLA, , Los Angeles, CA 90095-1510, USA.
authors.forename: Aaron
authors.initials: A
authors.lastname: O'Dea
authors.forename: Marian Lynne
authors.initials: ML
authors.lastname: Shaffer
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Doughty
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Wake
authors.forename: Felix A
authors.initials: FA
authors.lastname: Rodriguez
mesh_terms: D000818:Animals; D005075:Biological Evolution; D049628:Body Size / Q000502:physiology*; D005398:Fisheries; D049851:Gastropoda / Q000254:growth & development*; D010176:Panama; D012741:Sexual Maturation / Q000502:physiology*
keywords: Caribbean; Strombus pugilis; artisanal harvesting; fisheries-induced evolution; fossil; pre-Columbian