Other Conch Species
• Florida Crown
• Florida Fighting
• Florida Horse
• Hawking
• Milk
• West Indian Crown
• West Indian Fighting
Anatomy
• Shared with other gastropods (stomach-footed)• Reaches 30 cm in length• Mature conch has flared lip• Shell spines help reduce predation
– Larger shell
– Distributes crushing pressure over surface of shell
– Attachment device for epibionts to conceal shell
Habitat and Feeding Habits
• Seagrass beds
• Eats grasses, epiphytes and detritus
• Have you seen a conch on our dives?
• How big?
Juveniles
• Juveniles bury selves to escape predation, until ≈ 5 cm (Iverson et. al. 1989)
• Prime juvenile habitat:– Intermediate density of seagrass (30-80 g dry wt/m2 )
– 2-4 meters
– Strong tidal currents
– Most seagrass beds cannot support juveniles
Reproduction and Life Cycle
• Internal fertilization• Metamorphosis from larvae triggered by low
molecular weight compounds associated with red algae (Boettcher & Target 1997)
• Variations in shell development appear to be influenced more by local environment than genetic variability (Martin-Mora & James 1995)
Research
• Approximately 230 published papers by 1997
• Publication driven mainly by maricultural concerns
• Formal descriptions of larval stage of several Strombus species first appeared in 1993
Threats
• Over-”harvested” for…– Food
– Shell used for jewelry and decoration
• Productive areas become “sinks”
• Only 5,000-9,000 in Florida
• Fishing restrictions– Fishing moratorium in Florida since 1985 (little to no recovery,
relies on unpredictable current?)
– Bahamas restricted to free diving (unfortunately, juveniles and young adults are in the shallows)
Future
• Hatcheries producing millions of juveniles, but survival rate very poor compared to wild (Xanthid crabs a major predator of juveniles)– Thinner shells, shorter spines, low burial frequency
• Substrate enclosure? (Iverson et. al. 1989)
• May need higher density for males and females to detect one another (internal fertilization)
• Must begin to take a metapopulation perspective (Stoner 1997:21)
An Hypothesis Based on Info from Jyl
• Given that a colony of Conch will vacate an area once removed from that colony (Lapachin 1999), and…
• That under “natural” conditions there is much less predation of the adult vs. juvenile conch, then…
• Perhaps human predation has the double effect of not only removing a single conch, but also reducing survival of others due to energy-loss (= bears in the wild)
Early Images
• Teotihuacan 0-700 AD
• Central Valley of Mexico
• An empire’s symbol of control over distant ecological zones
Xochicalco
• Warring City States following the collapse of Teotihuacan
• Associated with the rain deity (Tlaloc?)
• Symbol of wealth
• Acquired by trade rather than conquest
The Mexica
• Ceremonial uses– cardinal directions– Tlaloque– maintain seasonal balance, duality
(Tlaloc/Huitzilopochtli)
• Trade and tribute
• Protein sources highly prized
Is there anything to learn from Mesoamerican civilizations?
• Not just balance in modern sense, but integration of humans & the rest of the “natural” world
• Vs. the natural/cultural approach, managed/wild• Sanctions for violating life (human sacrifice),
enculturation processes which produce a sense of awe and symbiotic pleasure (Nahua)
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