Complex larval connectivity patterns among marine invertebrate populations.

Area of Science:

• Marine Ecology
• Population Genetics
• Conservation Biology

Background:

• Coastal populations with planktonic larvae are often assumed to be highly connected due to ocean current dispersal.
• This assumption influences marine resource management and ecological understanding but is rarely tested directly.
• Challenges in tracking small, high-mortality marine larvae have hindered empirical validation of connectivity.

Purpose of the Study:

• To test the assumption of widespread larval dispersal in coastal invertebrate populations.
• To apply elemental fingerprinting to track the source of settled marine invertebrates.
• To compare larval connectivity patterns between two closely related mussel species.

Main Methods:

• Utilized elemental fingerprinting to trace the geographic origin of settled invertebrate larvae.
• Developed an in situ larval culturing technique to enable microchemical analysis of planktonic larvae.
• Compared connectivity patterns of Mytilus californianus and Mytilus galloprovincialis.

Main Results:

• Demonstrated that coastal mussel larvae are retained within 20-30 km of their natal origin, challenging dispersal assumptions.
• Elemental fingerprinting successfully identified larval sources for settled invertebrates.
• Mytilus californianus and Mytilus galloprovincialis exhibited significantly different larval connectivity patterns.

Conclusions:

• Larval retention, rather than widespread dispersal, appears to characterize these coastal mussel populations.
• Elemental fingerprinting is a viable tool for studying marine larval connectivity, even for species with planktonic development.
• Understanding species-specific connectivity is crucial for effective marine resource management, evolution, and ecological studies.